Leaders of Modern Industry by G. Barnett Smith: The Rennies

Note: This is a sub-section of Leaders of Modern Industry by G. Barnett Smith

John Rennie (The Elder)

The science of engineering owed many of its finest and most enduring developments to the genius of the Rennie family. The works of John Rennie and his two sons not only testify to their fame to-day, but must continue to do so for many generations. Some of the greatest mechanical enterprises and achievements ever witnessed in Great Britain are associated with their names; and this volume of sketches of industrial leaders may well and fitly close with a record of their labours.

John Rennie, the father, was born at the farm of Phantassie, in East Lothian, on the 7th of June, 1761. His father, like many other members of the family before him, owned the small farm which he cultivated. Farming was not an enviable occupation in the Lothians in the middle of last century, for roads were bad and communication difficult, and blackmailing and cattle-lifting were prevalent. Phantassie was on the old post-road between London and Edinburgh, but that did not benefit it much.

In 1763, when Rennie was two years of age, the first stage-coach between London and Scotland began to run. It only went once a month, however, and the journey from Edinburgh to London occupied from twelve to eighteen days. As young Rennie grew up he had aspirations beyond the quiet monotonous life which was a characteristic feature of the Scottish Lowlands. For a time he worked for Andrew Meikle, a farmer and millwright in the Phantassie district. Meikle was of an ingenious turn of mind, and invented a threshing-mill, which was capable of being worked by watery wind, or horses. Meikle took out a patent for the machine, and it proved to be a valuable boon to the husbandman, effecting an immense saving of labour as well as of corn. In course of time the threshing-mill was generally adopted in Great Britain, and, indeed, throughout the civilised world. It was Meikle who first stirred in John Rennie his love for mechanics and the science of engineering.

Old Rennie died in 1766, leaving nine children — four sons and five daughters. George, the eldest, managed the farm and acted as head of the family, though he was but seventeen years of age. William, the second son, went to sea, and died in America; and James, the third son, studied medicine in Edinburgh, went out to India, and was killed whilst dressing the wounds of his commanding officer at Seringapatam. John, being only five years old at the time of his father's death, was brought up under the care of his excellent mother. He was educated at the parish school of Prestonkirk, and was put to work, as we have seen, at Andrew Meikle's, where he remained for two years. Next he was sent to the Dunbar High School, where he showed such proficiency in mathematics, etc., that a visitor of the school said 'One would have imagined him a second Newton.' Then he returned home and to the workshop of his friend Meikle, whom he assisted in his plans and inventions.

At the early age of nineteen he was employed in fitting up new mills at Invergowrie, near Dundee. Subsequently he executed repairs at Aitcheson's flour-mills at Bonnington, near Edinburgh, employing cast-iron pinions instead of the wooden trundles formerly used. Dr. Smiles, in his Lives of the Engineers, states that he made quite an original mark as a country millwright. But he was already aiming at something much higher than this. Determined to acquire a thorough scientific training, he matriculated at Edinburgh University in 1780, and entered the classes of Dr. Robison, Professor of Natural Philosophy, and Dr. Black, Professor of Chemistry. In addition to studying strictly scientific works, Rennie acquired knowledge of the French and German languages. Music also beguiled his hours of recreation.

Having closed his college training in 1783, Rennie set forth upon a tour through the English manufacturing districts. By easy stages he reached Birmingham, and sought out James Watt, to whom he had a letter of introduction from Dr. Robison. Watt took to him at once, and remained his firm friend through life. Returning after some months to Phantassie, Rennie threw himself into mill and machinery work, and likewise constructed his first bridge. It was built for the Trustees of the County of Midlothian, across the Water of Leith, about two miles west of Edinburgh. But though he was full of work, he accepted an invitation from Watt to return to Birmingham, and early in 1785 he entered the famous works of Boulton and Watt at Soho. Here his mechanical genius soon manifested itself; and Watt thought so highly of Rennie that he committed to him the sole direction of the construction and fitting up of the machinery of the Albion Mills, London.

This important undertaking was successfully completed; and the ingenious improvements effected in the connecting wheel-work were so striking that Rennie at once rose into general notice, and abundance of mill-work speedily flowed in upon him. Watt was delighted with his young assistant's success; and the great Smeaton, who visited the Albion Mills, pronounced them to be 'the most complete in their arrangement and execution which had yet been erected in any country.' Rennie's system of wrought- and cast-iron wheels was soon generally adopted in all large machinery. The Albion Mills were unfortunately destroyed by fire in 1791, but upon part of the ground Rennie obtained leave to erect a workshop, in which he continued all through life to carry on the business of a mechanical engineer.

In 1792 Rennie undertook and completed his first work of civil engineering in England — the Kennet and Avon Canal, which extends from Newbury to Bath. The total length of the canal is fifty-seven miles. Many difficulties were experienced in cutting it, but all were effectually surmounted, and the various bridges, aqueducts, culverts, etc., successfully built. Among the finest architectural structures forming part of the canal is the aqueduct over the river Avon, about a mile from Limpley Stoke and six miles from Bath, which is greatly admired for the beauty of its elevation; and, indeed, wherever there is an aqueduct or a bridge upon the line of this canal, it will be found excellent in workmanship and tasteful in design. As a whole, the navigation was pronounced to be of the best executed in the kingdom, and the works have stood admirably down to the present time. In a commercial and national point of view the undertaking was of great importance, connecting as it did the navigation of the metropolis with that of Bristol and St. George's Channel, as well as opening up an extensive intermediate district; and it eventually proved highly remunerative to the proprietors.'

Rennie's next important undertaking, the Rochdale Canal, was even more difficult than the first, cuttings having to be made through hard rocky regions. This canal opened a direct water communication between the manufacturing districts of West Yorkshire and South Lancashire. Locks, reservoirs, strong bridges, and embankments were all necessary, and it is stated that George Stephenson encountered no more formidable difficulties in constructing his railway through the same district than Rennie did in constructing his waterway. But Rennie persevered, the canal was duly opened, and the engineer's sterling workmanship endures to this day. He further constructed the Lancaster Canal, and superintended the execution of the Grand Western Canal in Somerset, the Polbrook Canal in Cornwall, and the canal between Arundel and Portsmouth. He made elaborate reports on various other canals, and was extensively consulted as a canal engineer.

Fen drainage was another work in which Rennie achieved great and beneficial results. He first turned his attention to South Lincolnshire, and reclaimed the whole of that extensive district which extends along the south verge of the Wolds, from near the City of Lincoln eastward to the sea. Included therein were Wildmore Fen, West Fen, and East Fen, which comprised about 75,000 acres of land that for the greater part of the lay under water, thus being rendered comparatively useless either for pasturage or tillage.

Rennie was next consulted as to the draining of the Cambridgeshire Fens, and he conceived a grand scheme for the drainage of the Great Level, by means of more effectual outfalls and a system of intercepting catch-water drains. Unfortunately, however, the only part of the scheme executed during his lifetime was the Eau Brink Cut, for the purpose of securing a more effectual outfall of the river into the Wash near King's Lynn. In 1807, Rennie reclaimed 23,000 acres of fertile land in the district of Holderness, near Hull; in 1812 he was engaged in embanking lands exposed to the sea, when he succeeded in effectually protecting the thirty miles of coast extending from Wainfleet to Boston, and thence to the mouths of the rivers Welland and Glen; and in 1814 he produced a plan, which was carried out, for protecting the Earl of Lonsdale's valuable marshland on the south shore of the Solway Firth. 'It has been said of Mr. Rennie,' remarks Dr. Smiles, 'that he was the greatest "slayer of dragons" that ever lived — this title being given in the Fens to persons who, by skill and industry, have perfected works of drainage, and thereby removed the causes of sickness and disease, typified in ancient times as dragons or destroyers. In this sense, certainly, Mr. Rennie is entitled, perhaps more than any other man, to this remarkable appellation.'

Rennie's most widely-accepted claim upon posterity, however, is as one of the greatest bridge-builders of the world. We have already seen that he began his noble series of structures with the bridge over the Water of Leith, near Edinburgh, and it now remains to consider his more important works in this category. The first of these was the bridge across the Tweed at Kelso, designed in 1799 and opened in 1803. It consists of five semi-elliptical arches of 72 feet span, each rising 28 feet, and 4 piers, each 12 feet thick, with a level roadway 23 feet 6 inches wide between the parapets, and 29 feet above the ordinary surface of the river. It was one of the first bridges constructed with a level roadway, and was succeeded by the engineer's new bridge over the Esk at Musselburgh.

Rennie's earliest English bridge, and the first of his cast-iron bridges, was that thrown over the Witham at Boston, Lincolnshire, in 1803. Like all Rennie's bridges, it is elegant in appearance, and consists of a single arch of iron ribs, forming the segment of a circle, the chord of which is 80 feet. During the next fifteen or twenty years Rennie was called upon to construct a great number of minor bridges, and while erecting one at Newton Stewart, across the Cree, he nearly lost his life during a heavy flood, which swept down the valley with great fury.

The finest and most celebrated of Rennie's bridges — to return to his greater works — is the Waterloo Bridge over the Thames. It was commenced in 1811, and finished in less than six years, at a cost of upwards of £1,050,000. Mr. D. K. Clark, in describing the bridge, says it 'has a level roadway, carried on nine equal semi-elliptical arches, of 120 feet span each, and 32 feet rise, leaving a clear height of 30 feet above high-water spring tides. It was built of granite, in a style of solidity and magnificence previously unknown. Inverted arches were built between the elliptical arches in order to counteract the lateral pressure. The elliptical arch was carried to a greater extent of flatness than in bridges previously built. Isolated coffer-dams upon a great scale, in a tidal river, with steam-engines for pumping out the water, were employed in the building of this bridge, for the first time, it is believed, in Britain. The length of the bridge between the abutments is 1,380 feet, and the width between the parapets is 42 feet 4 inches. The long inclined approach on the Surrey side is formed by a series of 39 semicircular arches of 16 feet span, besides an elliptical arch of 26 feet span, over the Narrowwall Road, and an embankment of 165 yards long, on an inclination of 1 foot rise in 34 feet of length. The total length of the bridge, with approaches, is 2,456 feet, or nearly half a mile.'

Waterloo Bridge was opened on the 18th June, 1817, by the Prince Regent. The Duke of Wellington and many other distinguished personages were present at the imposing ceremony. Originally called the Strand Bridge, its name was changed to that of Waterloo, in honour of the Iron Duke. The Prince Regent offered to confer the honour of knighthood upon Rennie, but the engineer declined it, being content to remain a simple citizen. He wrote afterwards to a friend, 'I had a hard business to escape knighthood at the opening.' As Dr. Smiles justly remarks, 'Waterloo Bridge is indeed a noble work, and probably has not its equal for magnitude, beauty, and solidity. Dupin characterized it as a colossal monument worthy of Sesostris or the Caesars and what struck Canova most during his visit to England was, that the trumpery Chinese bridge, in St. James's Park, should be the production of the Government, whilst Waterloo Bridge was the enterprise of a private company. Like all Rennie's works, it was built for posterity. That it should not have settled more than a few inches - not five in any part - after time centres were truck, is an illustration of solidity and strength probably without a parallel. We believe that to this day not a crack is visible in the whole work.'

Southwark Bridge was Rennie's next undertaking. It extends from Queen Street, Cannon Street, to Bridge Street, Southwark, and consists of three cast-iron arches, with two stone piers and abutments. The arches are flat segments of circles, the centre one being not less than 240 feet span, rising 24 feet, and springing 6 feet above high-water of spring tides. The two side arches are of 210 feet span, each rising 18 feet 10 inches, and springing from the same level. The two piers are 24 feet wide each at the sprinting, and 30 feet at the base. The first stone was laid by Admiral Lord Keith early in 1815, and the bridge was opened for traffic in March, 1819.

In constructing this bridge, great precautions had to be exercised in securing the foundations of the piers, as the Thames was here at its narrowest and deepest point. The coffer-dams were consequently made of unusual strength and depth, and were constructed in the form most capable of resisting external pressure. The stone and iron work were alike splendid; and Robert Stephenson, in describing the structure in his article on 'Iron Bridges' in the Encyclopedia Britannica, said that as an example of arch-construction, it stands confessedly unrivalled as regards its colossal proportions, its architectural effect, and the general simplicity and massive character of its details.'

Rennie's achievements in dock and harbour construction are almost equally famous. The London Docks, the East and West India Docks at Blackwall, the Hull Docks, the Prince's Dock at Liverpool, and those of Dublin, Greenock, and Leith were all designed by him, and wholly or partially executed under his own superintendence. When the London Docks were constructed, it was determined to limit the access in the first instance to the Middle River entrance at Bell Dock, 150 feet long and 40 feet wide. The entrance lock communicated with the Wapping Basin, which covered a space of 3 acres, and this again led to the great basin called the Western Dock, 1,263 feet long and 960 feet wide. The bottom of the dock was laid 20 feet below the level of high water of an 18 feet tide; and the quays next to the river were 5 feet above high water, increasing to 9 feet at the great dock.

Other docks were subsequently constructed, communicating with each other and with a larger and deeper entrance lower down the river at Shadwell. Rennie began the work of making the docks early in 1802, and they were completed in January, 1805. Some time after the docks were opened, Rennie suggested that the whole of the lifting cranes should be worked by the power of a steam-engine instead of by human or by horse labour. Yet although he estimated the saving at £1,500 a year, while greater regularity and despatch would also be secured, the innovation was regarded as too bold a one to be attempted. He further suggested the adoption of tramways all round the quays, provided with trucks, but this labour-saving process was likewise in advance of the time.

The East India Docks, constructed solely for vessels of the East India Company ranging from 1,000 to 1,800 tons burden, were opened in August, 1806. They had an entrance lock into the Thames 210 feet long and 47 feet wide. The Export Dock was 760 feet long and 463 feet wide, covering a surface of 8 and a third acres; and the Import Dock was 1,410 feet long and 463 feet wide, covering a surface of 18 and two-third acres. The depth of the basins was 22 feet below high-water mark of ordinary spring tides; and the total surface of dock room, including quays, sheds, and warehouses, was about 55 acres. The docks were eventually united to the West India Docks, under the joint directorate of the East and West India Dock Company.

Among improvements introduced by Rennie in these docks were iron roofings for the sheds and a new description of iron cranes. It is stated that his machinery for transporting immense blocks of mahogany by a system of railways and locomotive cranes effected in six months a saving in men's wages more than sufficient to defray their entire original cost. Another excellent work effected by Rennie was the improvement of the Clyde by a system of dredging and by the erection of numerous jetties, etc., which rendered this important waterway a splendid navigable river. He also greatly improved the Grimsby Dock walls, and invented the system of curved walls for resisting the pressure of water.

The original Holyhead Harbour works were the construction of Rennie. They were begun in 1810 and finished after his death. The works consisted of a pier 1,150 feet long, and terminating at a depth of about 14 feet at low-water of spring tides; at 80 feet distance from the extremity of the main Pier there was a jetty 60 feet long, carried out at right angles to its inner face, to check any swell which might come round the pier-head from entering the harbour, and to throw it upon the opposite shore. The roadway was 50 feet wide, and 8 feet above the level of high-water of spring tides, the parapet being 7 feet higher. The harbour was laid out with a view to further extensions, and the engineer made some valuable suggestions in this respect, but they were not adopted. An entirely new harbour was constructed by the Government in 1847-73, at an enormous expense. This was subsequently extended, and the quay lengthened to 4,000 feet.

Rennie constructed the Howth and Kingstown harbours, but the latter vas still incomplete when he died, and the original design was afterwards departed from. He further constructed the Hull Docks. The principal one, the Humber Dock, begun in 1803 and finished in 1809, was 900 feet long by 370 wide, covering a surface of 7 acres. It was while constructing these works that Rennie invented the dredging-machine, as now used, for the purpose of clearing the basins of mud and silt. A list is given of no fewer than fifty harbours and docks which this indefatigable engineer constructed wholly or in part, or greatly improved.

Rennie himself thus described the broad principles upon which harbours should be constructed: 'Every harbour should be so constructed as to have its mouth as much exposed as possible to the direction from whence vessels can most conveniently enter in stormy weather when they are least manageable; but the heads should be made of such a form as to admit of the least sea entering it, or so as to occasion as little swell within the haven as possible. This cannot by any practicable construction be entirely avoided; but means should be provided within the harbour so as to reduce the recoil of the waves to a minimum, — for it is the undertow or retiring sea, after the breaking of a wave, that renders vessels most unmanageable by making the helm lose its effect. At such a time the mariner is at a loss what to do, or how to manage his vessel; and for the want of due attention to these particulars many of the most artificial harbours in the kingdom are exceedingly difficult of access, and some of them are most unsafe even when entered.'

That useful accessory in harbour-building, the diving-bell, was vastly improved by Rennie while he was engaged upon extensive repairs in the Ramsgate Harbour works in 1813. His biographer states that he proceeded to design and construct a bell of cast-iron, about 6 feet in height, and 4.5 feet wide, and 6 feet long, having one end rather thicker and heavier than the other, that it might sink lower, and thus enable the exhausted or breathed air more readily to escape. At the top of the bell eight solid bull's-eyes of cast glass were fixed, well secured and made water-tight by means of leathern and copper collars covered with white lead, and firmly secured by copper screw bolts. To the top of the inside were attached two strong chains for the purpose of fastening to them any materials that might be required for the work, and flanges were cast along the sides of the bell, on which two seats were placed, with footboards, for the use of the men while working.

In the centre of the top was a circular hole, to which a brass-screwed lining was firmly fixed, and into this a brass nozzle was screwed, having a leathern watertight hose fastened to it, 2.5 inches in diameter. The hose was in lengths of about eight feet, with brass-screwed nozzles at each end, so that it could be lengthened or shortened at pleasure, according to the depth of water at which the men in the bell were working. For the purpose of duly supplying the machine with air, a double air-pump was provided, which was worked by a sufficient number of men. The air-pump was connected with the hose referred to, and was either placed on the platform above or in a boat which constantly attended the bell while under water. Two stout wrought iron rings were fixed on the top of the machine, to which ropes or chains were attached for the purpose of lowering or raising it. The whole weighed about five tons; and it was attached to a circular frame-work of timber, strengthened by iron, erected over where the intended new circular pier-head was to be built, and so fixed to a pivot near the centre of the work, that it was enabled easily to traverse its outer limits.

On the top of the framework was a truck, made to move backwards or forwards by means of a rack on the frame, and a corresponding wheel provided with teeth, worked by a handle and pinion. On the truck were placed two powerful double-purchase crabs or windlasses, one for working the diving-bell suspended from it, and the other for lowering stone blocks or other materials required for carrying on the operations at the bottom of the sea. By these ingenious expedients the building apparatus was so contrived as to move all around the new work, backwards and forwards, upwards and downwards, so that every part of the wall could be approached and handled by the workmen, no matter at what depth, whilst the engineer stationed on the pier-head above could at any time ascertain, without descending, whether the builders were proceeding in the right direction, as well as the precise place at which they were at work.

The Ramsgate Harbour improvements were so expeditiously and successfully completed, that the trustees caused a memorial stone to be fixed in the centre of the new pier-head, bearing a bronze plate on which were recorded the details of Rennie's ingenious labours, as well as their own obligations to the engineer; and they also presented him with a handsome piece of plate.

The Bell Rock, or Inchcape, Lighthouse, was a fine work executed by Rennie and Robert Stevenson, the Scotch engineer. It was begun in 1807 and finished in 1810, at a cost of £61,000. The site is a reef of Old Red Sandstone rocks in the German Ocean, twelve miles south-east of Arbroath, and nearly opposite the mouth of the Tay. The reef is 2,000 feet long; at high-water of spring tides it is covered to a depth of 16 feet; at low-water it is partly uncovered to a height of 4 feet; and for a hundred yards around, the sea is only three fathoms deep. This dangerous reef was formerly a fruitful cause of ship-wreck, and according to tradition, the Abbot of Aberbrothock, or Arbroath, placed a bell on it, 'fixed upon a tree or timber, which rang continually, being moved by the sea, giving notice to the saylers of their danger.' Southey has enshrined the legend in one of his best ballads.

Many plans were suggested far a lighthouse on the Bell Rock before Rennie examined the spot and made a report to the Commissioners of Northern Lights, recommending a substantial stone lighthouse, similar to that on the Eddystone, as being the only kind of structure calculated to meet the necessities of the case. The report was adopted, and the works authorised, and carried out as stated. The lighthouse was 127 feet high, and the plan of construction generally followed was that of Smeaton with the Eddystone Lighthouse, one of the few deviations consisting in the substitution of dove-tailed pieces of stone for chain-bars in the joints both of the walls and the floors. Rennie designed the structure and was chief engineer, and the works were practically executed by Robert Stevenson, the resident engineer. Dangers and difficulties attended the accomplishment of the task, but in 1810 the Bell Rock Lighthouse shed its friendly light across the tempestuous ocean for the benefit of the imperilled mariner.

Rennie was employed by the Government on many public works. He advised the Navy upon the improvement of their flour-mills at Rotherhithe, which were worked by the rise and fail of the tide; and when there was great alarm in England in 1803, owing to the possible descent of Napoleon upon our shores, he devised means for the sudden flooding of the valley of the Lea round London, in order to check the approach of a hostile army from that quarter. He further laid out and constructed the Hythe Military Canal on the coast of Kent, which was defended by earthworks, and protected by a breastwork on the land side. He next fixed moorings in the tideways of the royal harbours, improved the machinery of the Waltham Powder Mills, cleared the Thames in front of Woolwich Dockyard of its immense accumulation of mud, erected a quarantine establishment in the Medway, provided wet docks for the Royal Navy, and introduced improved machinery at the various dockyards. The Royal Dockyards — Portsmouth, Plymouth, Deptford, Chatham, etc. - were not only far apart, but some of them were ill-adapted to their purposes.

Having been commissioned by the Admiralty to find a site on the Thames for a great naval arsenal and harbour, Rennie recommended Northfleet as possessing every advantage that could possibly be wished for in a naval station. He was not allowed to carry out his design, however, but was instructed instead to construct extensive dock-works at Sheerness, that spot being chosen by the authorities as commanding the entrance both to the Thames and the Medway. We learn that 'the plan finally decided upon was that of a river-front, extending from the Garrison Point to near the Old Town Pier of Sheerness, of the length of 3,150 feet, including the entrances, and enclosing within it three basins: one to the north, 480 feet long and from 90 to 200 feet wide, containing a surface of about two acres, 4 feet below low-water of spring tides, with two frigate docks and a building-slip and boat-slips; a central tidal basin 220 feet square, of the depth of 2 feet below low-water, with storehouses around it for the reception and delivery of victualling and other stores; and on the west end of the dockyard a basin 520 feet long and 300 feet wide, covering a surface of nearly four acres, provided with dry docks for ships of the line on the south side, with their sills and the bottom of the basin laid 9 feet below low-water of spring tides, westward of which were the mast-ponds, mast-locks, and workshops. In the rear, on the south of these works, were placed saw-pits, timber-berths, and the officers' houses. The total surface of the dockyard was 6434 acres. The foundation-stone of the docks was laid by the late Lord Viscount Melville in 1815, and the works were the commenced and continued without interruption until the year 1826, when the whole were completed.

`Their execution was attended with many difficulties, and necessarily required a great deal of Mr. Rennie's care and attention. The foundations were a soft running sand, extending to an almost fathomless depth. The strong currents flowing past the place rendered it necessary to adopt an entirely new system of operations, which were carried out to an extent never before attempted in so exposed a situation. The form of sea-wall was devised which should most effectually resist the strong pressure of the current and the heavy swell beating upon its outer side, without yielding to the lateral pressure or thrust of the water of the basins and the earth by which it was backed. At the same time, the weight necessary to ensure stability must not be such as to sink vertically.

'Mr. Rennie adopted the means to secure these objects which he had employed with such success at Grimsby Docks in 1797, namely, to take the like quantity of materials as would have been necessary for an ordinary wall, and dispose of them in such a form, that the same weight should be distributed over a greater surface, thus diminishing the vertical pressure. In the foundations of the walls he also adopted the method employed by him in similar works, of driving the piles and cutting off their heads at an angle inclining inwards, or towards the land side, laying the courses of stone at the same angle; which a greater resistance was offered to the pressure of the earth, and the building was prevented from being pushed outwards, as was more or less the case in most of the walls built on the old construction. The entrance gates to the basin were also planned and executed with great skill, Mr. Rennie carrying into effect the same simple but correct principles laid down by him in his report on the Northfleet Docks, making the direction of the entrance suitable to the current in the Medway, from which the ships entered the port.'

Other branches of dock-work executed by Rennie included a new river wall, with ship-basin and two building-slips, at Woolwich; the new dockyard, building-slips, and dry dock, at Pembroke; the new entrance to Deptford Basin; and various improvements at Chatham, Portsmouth, and Plymouth.

But one of his most gigantic undertakings was the famous Plymouth Breakwater. It is the best known of all engineering works of the kind. In their article on 'Breakwaters' in Chambers's Encyclopaedia, Messrs. D. and T. Stevenson describe the Plymouth Break water as follows: 'The sound or harbour, being open to the south, was so much exposed to storms that, early in the present century, it was determined to construct a breakwater across its mouth, with openings between it and the shore, on either side, for the ingress and egress of shipping. The works were commenced in 1811, from designs by Rennie, and were estimated to cost £900,000. The operations consisted in transporting along a tram-road large blocks of limestone got from a neighbouring quarry, shipping them in vessels fitted with trap-doors, and by means of these, depositing them in the shape of a huge mound in the required situation. The design was to carry the rubble mound to a height of ten feet above low-water, to give the seaward face a slope of 3 to 1, and the inner face 1.5 to 1, and the width on top 30 feet.

'As soon as the stones began to appear above water, a perceptible benefit resulted in the relative calmness of the sound during the prevalence of storms; but the structure was frequently very roughly handled by the waves, which altered and flattened its shape. A severe storm in November, 1824, overthrew a length of 796 yards of the finished work; after this the breakwater was raised 10 feet higher, the seaward slope made 5 to 1, and the top width 45 feet, the top and slopes paved with masonry, and the top protected with expensively dressed granite blocks, joggled together and bedded with cement. It was not until 1841 that the works were finally completed by the deposit of more than 3,000,000 tons of stone, and an expenditure of nearly £1,500,000. The breakwater is nearly a mile long, the central portion is 1,000 yards; and two wings, of 350 yards each, extend from the ends of this at a slight angle. The open channels at each end, between the breakwater and the shore, are each about hall a mile wide, and their depth is respectively 40 and 22 feet at low-water. The breakwater is 400 feet wide at the base, and 45 at the top — the two sides being made very sloping for the security of the stones. The slopes and top are faced with masonry. The water-space protected by this breakwater comprises 1,120 acres, and it is generally admitted that the money has been well spent on the work. The breakwater requires constant repair.'

Dr. Smiles states that the actual amount of rubble deposited for the Plymouth Breakwater to the end of 1848 — when the work may be said to have been completed — was 3,670,444 tons, besides 22,149 cubic yards of masonry, or an amount of material at least equal to that contained in the Great Pyramid. The breakwater 'may in all respects be regarded as a magnificent work, worthy of a great maritime nation.'

Other labours of Rennie remain yet to be mentioned. He cut the Crinan Canal, and reported on the water-supply of Manchester, Edinburgh, Leeds, Bristol, Doncaster, and many other large towns at home and abroad. He erected the anchor-forge at Woolwich Dockyard, advised the Bank of England on its machinery for the manufacture of bank-notes, and supplied the Dutch with designs of dredging-machines for clearing the mud out of the rivers and canals. He constructed the machinery for making ropes according to Captain Huddart's patent. He urged the introduction of steam-power into the Royal Navy, and constructed a small steamboat called the Comet, which was the precursor of other royal ships of vaster dimensions. The last of his great engineering works, New London Bridge, he did not live to complete. His design consisted of five semi-elliptical arches, the centre one 150 feet span, the two side arches 140 feet each, and the two land arches 130 feet each, making a total lineal waterway of 690 feet the height of the soffit, or underside, of the central arch being 29 feet 6 inches above the level of Trinity high-water mark. The design was generally approved, and a Bill carried through Parliament, but — as we shall presently see — his son John carried through the work.

Rennie rarely took any rest from his labours, which extended over a period of forty or fifty years; but in September, 1816, he visited France with his friend, James Watt, jun. At Cherbourg he examined the famous breakwater then in course of construction, and be also took notes of the building-yards and docks of other towns and cities. In 1820 his health began to fail, but he persisted in going about for some twelve months after that. He was in the midst of designs for new enterprises, when he expired somewhat suddenly on the 4th of October, 1821. His remains were interred in St. Paul's Cathedral, near to those of Sir Christopher Wren. At the age of twenty-nine Rennie had married an Inverness lady named Miss Mackintosh, with whom he had ever lived happily until her death, which occurred a few years before his own decease. They had nine children, six of whom survived their parents. One who knew Rennie well thus wrote of him in the Gentleman's Magazine, shortly after his death:-

Every part of the United Kingdom possesses monuments of his glory, and they are as stupendous as they are useful. They will present to our children's children objects of admiration for their grandeur and of gratitude to the author for their utility. Compare the works of Rennie with the most boasted exploits of the French engineers, and remark how they tower above them. Look at the breakwater at Plymouth, in comparison with the caissons at Cherbourg anyone of his canals with that of Ourke, and his Waterloo Bridge with that of Ruilly. Their superiority is acknowledged by every liberal Frenchman. He cultivated his art with the most enthusiastic ardour, and instead of being merely a theorist, he prepared himself for practical efficiency by visiting and minutely inspecting every work of magnitude in every country that bore similitude with those which he might be called on to construct; and his library abounded in a richer collection of scientific writings than that of almost any individual. The loss of such a man is irreparable. Cut of in the full vigour of his mind, his death seems to suspend for a time the march of national improvement, until the just fame of his merit shall animate our rising artists to imitate his great example, and to prepare themselves by study and observation to overcome, as he did, the most formidable impediments to the progress of human enterprise, of industry, and of increased facility in all the arts of life. The integrity of Mr. Rennie in the fulfilment of his labours was equal to his genius in the contrivance of his plans and machinery. He would suffer none of the modern subterfuges for real strength to be resorted to by the contractors employed to execute what he had undertaken. Everything he did was for futurity, as well as present advantage. An engineer is not like an architect. He has no commission on the amount of his expenditure, if he had, NIL Rennie would have been one of the most opulent men in England, for many millions have been expended under his eye. But his glory was in the justice of his proceedings, and his enjoyment in the success of his labours. It was only as a millwright that he engaged himself to execute the work he planned, and in this department society is indebted to him for economising the power of water, so as to give an increase of energy, by its specific gravity, to the natural fall of streams, and to make his mills equal to four-fold the produce of those which, before his time, depended solely on the impetus of the current. His mills of the greatest size work as smoothly as clockwork, and by the alternate contact of wood and iron, are less liable to the hazard of fire by friction. His mills, indeed, are models of perfection.

If the death of such a man is a national loss, what must it he to his private friends and to his amiable family? Endeared to all who knew him by the gentleness of his temper, the cheerfulness with which he communicated the riches of his mind, and forwarded the views of those who made useful discoveries or improvements in machinery or implements, procured him universal respect. He gave to inventors all the benefits of his experience, removed difficulties which had occurred to the author, or suggested alterations which adapted the instrument to its use. No jealousy nor self-interest ever prevented the exercise of this free and unbounded communication; for the love of science was superior in his mind to all mercenary feeling.

Rennie was a man of punctual and systematic habits, with a great love of order. All the reports he drew up were model documents. He declined to speculate in enterprises in which he was concerned, even when he knew such speculations would prove profitable. In person he was commanding of stature, and possessed of Herculean strength. He was eminently truthful, honest, and upright; was profound in mind, sagacious and serene in character; and his modesty was as conspicuous as his genius.

George and John Rennie

George Rennie, the eldest son of John Rennie, was born in 1791, and educated at Edinburgh University. When twenty years of age he began the study of practical engineering under his father in London. Appointed superintendent of the machinery of the Mint in 1818, he at the same time assisted in the planning and execution of several of his father's later works. Upon his father's death he entered into partnership with his younger brother John as engineers and machinery constructors; and during the existence of the firm it carried on an immense business, including the execution of most of the works which had been designed by his father, and the completion of those which he had left unfinished. The undertakings of the two brothers embraced the construction of bridges, harbours, docks, shipyard and dredging machinery, steam-factories both in Great Britain and on the Continent, and marine engines for warships, They built ships both of wood and iron, drained large tracts of land in the midland counties of England, and superintended the construction of several continental railways. George Rennie died in 1866.

Sir John Rennie, John Rennie's youngest son, claims fuller attention as being the most widely-known member of his family. In the interesting autobiography which he left behind him, he states that he was born in Stamford Street, Blackfriars, London, on the 30th August, 1794. He was sent to Dr. Greenlaw's school at Isleworth, where the most remarkable pupil at this time was the poet Shelley, of whom he gives a striking picture. Rennie afterwards went to the school of the celebrated Dr. Charles Burney, at Greenwich. Here he became a tolerable proficient in the classics.

When the days of tuition were over, the elder Rennie would not send his son to Oxford or Cambridge, as he intended to bring him up to the profession of a civil engineer, and he held that a young man could not bend himself to the practical part of the work after he had been to the University. At the close of his preliminary training, Rennie was invested with some amount of independent responsibility, and helped his father in the construction of the Vauxhall, Southwark, and Waterloo bridges. In 1813 he was despatched to Aberdeen and Peterhead to secure stone for the works. In 1814 he gained great experience in following the surveys made by Francis Giles in various parts of the country. Rennie made a tour in France and Belgium in August, 1815, and visited the scene of the sanguinary Battle of Waterloo. After his return he was closely engaged in the works connected with the Waterloo and Southwark bridges, the latter of which was almost entirely under his direction.

But he managed in the evenings to study mathematics, and to attend Sir Humphry Davy's lectures at the Royal Institution. Having received a tolerably good education, theoretical and practical, as a civil engineer, young Rennie was sent forth on his travels before beginning business fully on his own account. His father considered that he should study what had been done ancient and modern times, both in architecture and engineering. Accordingly, in June, 1819, he left England — in company with his cousin, General Sir J. Aitchison, and Lord Hotham – for a tour through Switzerland, Italy, Greece, Asia Minor, Turkey, and Egypt. He gives graphic descriptions of Milan, Venice, Bologna, Rome, and other cities, always keeping his eye on those works — harbours, canals, roads, and bridges which especially appealed to him as a civil engineer.

At Rome he made the acquaintance of Canova and Thorwaldsen, and saw Lawrence, Chantrey, and Turner, whom he had known in England. He attended the splendid receptions given by the beautiful Princess Borghese, the Duchess of Devonshire, and others. Naples, Corfu, Zante, Patras, Corinth, Athens, Argos, Mycenae, were all visited in turn; and at Athens the travellers saw and conversed with Byron's beautiful Maid of Athens. Then came Smyrna, Ephesus, Miletus, Broussa, Constantinople, Alexandria, and Cairo. In the last-named city Rennie had an audience of the celebrated Pasha Mehemet-Ali. He was seized with fever at Cairo, and had a renewal of it in Italy on his return voyage. Florence, Leghorn, and Genoa he subsequently visited, and he was struck by the magnificent site which the Gulf of Spezzia afforded for a naval arsenal. This idea has since been partially realised.

Rennie reached England in September, 1821, and in less than a fortnight after his landing he was called upon to mourn the loss of his father. The sad event prostrated him for a time, but as soon as he recovered from the shock he was stimulated to earnest labour by the brilliant example of his father. His first ambition was to succeed him in his numerous great works then being carried on by the Admiralty, such as the Plymouth Breakwater, and the new Chatham and Woolwich Dockyards. Although he was only twenty-seven years of age, he was at once appointed by the Lords of the Admiralty to succeed his father as their engineer. Next, he was appointed drainage engineer to the Eau Brink Commissioners, who had been chosen to carry into effect the Eau Brink Cut, for the improvement of the drainage of the great level of the fens, called the Bedford Level, amounting to about 300,000 acres of valuable land. This scheme consisted of a cut for altering the channel of the Ouse, by means of which nearly two miles of the navigation of that river would be saved, and an additional fall for the drainage of five feet perpendicular would be gained. This great work had been planned nearly a century before, but had always been opposed by the inhabitants of the fens as being inadequate. At length it was resolved to proceed with the scheme, but so many difficulties arose that the whole of the funds subscribed, amounting to about £80,000, were expended in litigation and in the cost of obtaining the Act of Parliament. A second Act of Parliament was subsequently obtained, and the Commissioners elected to carry out the undertaking were Lord William Bentinck, Sir Andrew Hammond, Bart., Sir Charles Browne, M.D., and Mr. Thomas Hoseason. Messrs. Jolliffe and Banks received the contract for the works, and, as already stated, John Rennie was appointed drainage engineer.

'The effect of this work,' says Rennie, 'greatly exceeded the most sanguine expectations of its supporters. Immediately after it was opened, the low-water mark at the upper end of the cut fell five feet, and the drainage waters were carried off with a degree of rapidity which astonished the whole country. The autumn and winter of 1821-22 was characterised by an unusual quantity of rainfall, and if it had not been for the opening of the Eau Brink Cut the whole, or the greater part, of the level of the fens would have been under water, and therefore the fen men were very well pleased with the result. At this time I was appointed to succeed my father as chief drainage engineer, and the late Mr. Telford had been previously appointed chief engineer for navigation. Immediately after my appointment, which was in the month of December, 1821, I went to Lynn to examine the works, and was much astonished to find the great effects which had been produced by the Eau Brink Cut. Instead of the circuitous old shallow course, full of shoals and obstructions of every kind, there was a fine, straight, deep channel, two miles shorter than the old one, of the proper width, bordered by strong banks of the full height; the floods passed off without difficulty, and the navigation was so much improved that the lighters and barges going up the river from Lynn saved several tides. It is true, that upon examining the country between Denver Sluice and Cambridge, there was a great deal of water out in several places, but this was attributed to the interior drains and rivers not being properly defended and embanked, so that they could carry off the water to the main outfall below. I also examined the new steam pumping apparatus, which had lately been erected for draining Soham and other fens. This, although proposed by my father in 1786, was the first of the kind that had been erected. It consisted of a scoop wheel, with a perpendicular lift, worked by a condensing engine. It answered its object completely, and has since been imitated by numerous others with equal success in different parts of the fen and lowland districts.'

Rennie's next appointment was as engineer-in-chief to Ramsgate Harbour, again succeeding his father. This harbour was established by special Act of Parliament for the purpose of affording shelter to vessels of 300 tons lying in the Downs during south-west gales. In short, the harbour was made for clearing the Downs of small vessels, so that large ones might ride in safety, and this purpose was successfully answered. Hitherto, the heavy seas, and the proximity of the Goodwin Sands, had proved very dangerous for craft of all kinds. Further business flowed in rapidly upon Rennie, and he succeeded his father at Sunderland, Donaghadee, Port Patrick, and Kingstown Harbours, the West India Docks, and other places. But the most difficult and anxious work in progress at this time was the new dockyard at Sheerness, which Rennie now completed from his father's designs, the work also having been partially executed by the latter.

Rennie went down to Plymouth in March, 1825. Difficulties had arisen in connection with the breakwater, and there was a difference of opinion between Rennie and Joseph Whidbey, the superintendent of the breakwater, as to how they should be met. The Admiralty accepted Rennie's plans in preference to Whidbey's, and on the latter resigning his position, Rennie was appointed chief engineer. He was not long in erecting outer works which effectually broke the force of the waves before they reached the main body of the breakwater. Soon afterwards Rennie was ordered to erect a new Victualling Establishment for the Navy at Cremill Point, near Devonport, and he was further directed to report to the Admiralty on the feasibility of applying the Cornish system of high-pressure engines to the Admiralty steam-vessels.

Then came the greatest of the legacies left him by his father, viz., the building of new London Bridge. This was a most arduous undertaking. 'New London Bridge,' observes Mr. Clark, ' as built 180 feet higher up the river than the old bridge. It consists of five semi-elliptical arches, the least of which is wider than any other elliptical arch ever before erected. The centre arch has 152.5 feet span, with 37.5 feet rise; the next two arches are of 140 feet, and the two abutment arches are of 130 feet span. The roadway is 52 feet wide. The clear waterway at all times of the tide is 692 feet, or 60 feet more than the old bridge afforded at high-water. The whole length of the bridge is 1,005 feet. At the City side the bridge is carried over Thames Street on a dry arch. At the Borough or south side the approach is formed on an inclined plane, supported on a series of brick arches, with a large dry arch facing Tooley Street.

'This bridge deserves further remark for the difficulty of the situation in which it was built, above the old bridge, in a depth of from 25 feet to 30 feet at low-water, on a soft alluvial bottom, covered with large loose stones, scoured away by the force of the current from the foundations of the of bridge. The whole of these stones had to be removed by dredging before the coffer-dams for the piers and abutments could be commenced; otherwise it would have been extremely difficult, if not impracticable, to have made them watertight. The difficulty was further increased by the old bridge being left standing, to accommodate the traffic, whilst the new bridge was building, and the restricted waterway of the old bridge occasioned such an increased velocity of the current as materially to retard the operations at the new bridge. At times the tide threatened to carry away all before it; and it was found expedient that two of the small arches of the old bridge on each side should be thrown into one, to compensate for the additional obstruction which the water occasioned to the navigation. The piers and abutments stand upon platforms of timber, the floors of the coffer-dams resting upon piles about 20 feet long. The masonry is from 8 feet to 10 feet below the bed of the river. The great magnitude and extreme flatness of the arches, of which the key-stones are 4 feet 9 inches long, demanded unusual care in the selection of the materials, which were of the finest blue and white granite from Scotland and Devonshire, as well as great accuracy of workmanship. The new bridge was opened for traffic in August, 1831, the period occupied in its erection, from the time of driving the first pile for the dam of the south pier, being seven years, five months, and thirteen days.

'The centering employed for the new London Bridge is worthy of notice. It consisted of trussed timber girders, supported at the piers. The striking plates and wedges, by which the centre was lowered after the completion of the arch, were strong beams suitably notched, one of which, the wedge, was kept in its place by cross wedges. When the centre was to be lowered, the cross wedges were knocked out, and the main wedge driven back.'

William IV. opened the new London Bridge with great state. His Majesty walked over the whole of the bridge, accompanied by the Ministers of State, the Lord Mayor and Corporation, and the Bridge Committee. The Tower guns volleyed at intervals, and as the day was remarkably fine, the Thames was crowded with boats filled with gaily-dressed people. The original London Bridge, which in its first form dated back to 1176, was removed in 1834, under Rennie's supervision, at a cost of £10,000. After the opening of the new bridge, Rennie received the honour of knighthood for his services.

In order to make worthy approaches to new London Bridge, Rennie, and his brother-in-law, Cockerell, who was an excellent authority, submitted designs to a Committee of Taste appointed by Parliament for the beautifying of London. Their designs were rejected, however, and the Committee authorised the late Sir Robert Smirke, then one of the Crown architects, to design the present buildings on both sides of the bridge, as far as King William Street on the north, and the old Town Hall of Southwark on the south. It is generally admitted, as Rennie has remarked, that 'a more unworthy set of buildings was never designed.' A rare opportunity was lost of constructing handsome and appropriate buildings to adorn one of the greatest thoroughfares in the world.

Drainage works next occupied Rennie's attention. The Eau Brink Cut was enlarged under his direction, for the damage done by its overflow, in consequence of the channel being too narrow, had involved the Commissioners in large amounts as compensation to the Lynn Harbour Trustees and others. He then, in conjunction with Telford, improved the River Nene, so as to render it a good outfall for the drainage of the extensive low fenlands bordering it, which, on account of their bad drainage, were frequently subject to floods, and comparatively valueless. It was necessary to stop up the old channel and to divert the river through the new outfall. Rennie gives this interesting and amusing account of how the work was accomplished:—

When everything was ready, we went down and met the contractors, Messrs. Jolliffe and Banks, and immediately gave them orders to commence filling up the old channel; they had about thirteen hundred men, and horses, carts, and materials, and appliances of all kinds, and set to work in right good earnest.

The Corporation of Wisbech, who had always opposed the measure, although they were compelled by the Act to contribute £30,000 towards it, which was perhaps the cause, offered every obstruction in their power, and said that the new outfall was not excavated deep enough according to the Act, and came down in their barge with their law officers, giving us official written notices to stop all proceedings. At this critical moment the contractors were rather taken aback; Mr. Telford and I, however, nothing daunted, ordered the men to proceed stopping the channel, and to take no notice of the Corporation. We further told them that if they did not go away their barge and all in it would be swamped, and that the responsibility would rest entirely with them. Seeing that we were in earnest, they turned tail, and, leaving their protest, returned to Wisbech. The third day afterwards the old channel was completely closed, and the Nene diverted to its new outfall.

It should be observed here that Mr. Telford and myself, calculating upon the loose nature of the soil, which was silt, and which we felt confident would scour when fairly acted upon by the current, only made the contract for the excavation to the level of low-water of spring tides; and therefore it would have wasted money to have excavated that which we knew the current would do for nothing. The current at first appeared to have very little effect; and the Duke of Bedford's manager, the late excellent and talented Tycho Wing, a school-fellow of mine at Dr. Burney's, became much alarmed, and was sadly afraid that the outfall would be a failure. Telford and I knew better, and assured him that our only doubt was whether the current would not be too strong, and render it necessary to protect the sides with stone. This we considered to be no disadvantage — on the contrary, a great benefit; for, making the cut small in the first instance, we should always be able to regulate the scour whenever it might have a tendency to enlarge the cut beyond the size necessary to discharge the drainage water effectually, at the same time preserving a sufficient depth for navigation; but, if it had been too large in the first instance, it could not have been properly adjusted afterwards. Mr. Wing was comforted by our assurances; still, he had his doubts, and two months elapsed before any sensible scour appeared to take place.

The fact was, the fall in the bottom was so little, that the current had to remove the obstacles to its progress, which it could only do by degrees, when it had accumulated sufficient fall or head; having done this, its progress was most rapid, and increased daily, so that within six months after it had been opened it had scoured out the bottom to nine feet below low-water of spring tides; the sides also had been regularly scoured away, and the area of the cut was increased to three times its original size. Spring tides, which had scarcely exceeded a few feet at Wisbech, and not much more at Cross Keys, rose remarkably at both places, so that vessels of considerable tonnage could reach Wisbech even at neaps, whereas before they could only get up there at spring tides. The trade of the port increased so rapidly that they were soon enabled to pay off the £30,000 which they had been previously obliged to borrow to contribute to the cost of the outfall.

Another undertaking in connection with the Nene is thus- described by Rennie:

It had long been a favourite idea with the late Lord William Bentinck and his friend Mr. Thomas Hoseason, of Banklands, to make a bridge across the Nene estuary, at Cross Keys, in order to shorten the distance between. the south of Lincolnshire and Norfolk. The bridge over the lower end of the Eau Brink had been completed, and another had been made at the Fossdyke Wash by my father, for the Welland; so that it was only necessary to make another across the Nene estuary, at Cross Keys, to complete this desirable line of communication. A company was accordingly formed for this purpose, of which Lord William Bentinck was the head. An Act was obtained at the same time as the Nene Outfall Act, and I was appointed the engineer. The Nene Outfall Commissioners obtained a clause in the Bridge Act compelling the Company to build the bridge over the Nene Outfall Cut at the same time; this I told them was very unwise, for as the bridge was to be built of wood, with a drawbridge opening in the centre to allow vessels to pass, it would be impossible to drive the great piles forming the piers of the bridge sufficiently deep to be below the scour in the outfall; the better plan would be to wait until the outfall had been scoured to its full depth, and then build the bridge.

My opinion was overruled; the bridge was built; and it was impossible, as I expected, to drive the piles to the requisite depth. Where the full effect of the scour had taken place, it was found necessary to secure the piles of the bridge by throwing a great mass of stone round them. This materially obstructed the current through the bridge, until at length there was a fall through it of from two to three feet, which greatly injured the drainage, so that the Nene Outfall Commissioners ultimately got an Act to make a new bridge for the Company at the Commissioners' expense. All this might have been avoided if the bridge had been built as I originally recommended.

The spot where this bridge and line of embankment is made is the same place where King John's army was lost, and where my father was nearly drowned some years before my time, crossing in his carriage, being overtaken by the tide. Six thousand acres of this Wash have been reclaimed from the sea by myself; and, where once the tides used to ebb and flow, fields are now under culture producing the finest crops.

Rennie next drew up a plan for draining Whittlesea Mere, and all the low fenny country around it, to the extent of 55,000 acres. He showed that by improving the Nene from Peterborough to the outfall, by making a main drain to Whittlesea Mere to connect it with the Nene, and by making a catch-water drain round the base of the surrounding hills, so as to discharge the highland water into the Nene at Peterborough and the Ouse at Hermitage Sluice, the whole country would be thoroughly well drained, and the navigation greatly improved, while there would be an ample supply of fresh water at moderate cost. Although this plan was approved by Robert Stephenson also, it was not adopted.

The Middle Level Corporation, in whose district lay the greater part of the lowlands to be drained, would not listen to it, but insisted on draining these lands by the Ouse, ten miles farther distant. This measure was carried out at double the cost of Rennie's plan, and a minor plan was substituted for the improvement of the Nene, which cost a great deal more than any benefits derived from it. But the sands below Lynn, at the mouth of the Ouse, accumulated to such an extent that the navigation up to that town was seriously obstructed. Rennie was consequently requested by a Committee to enquire into and report upon the whole subject. Rennie thus states what followed:

I accordingly employed nearly twelve months in surveying and levelling the Great Wash and the mouths of the Ouse, Nene, Welland, and Witham, which are the principal rivers discharging their waters into the Great Wash, and which drain all the adjacent fenlands, amounting to nearly a million of acres, besides the highlands. I found that by improving all the mouths of these rivers, an additional fall of seven feet might be gained for the Ouse, two feet for the Nene, and a similar amount for the Welland and the Witham, and recommended that all these rivers should be united and made to discharge their waters into one great main channel in the centre of the Great Wash, and that the main and minor channels should be properly embanked. By this means, not only would all these rivers be much improved, and the drainage and navigation rendered as perfect as they could be made, but, in addition to this, from 150,000 to 200,030 acres of land would be gained from the Wash, or, in other words, a new county, of most valuable land, would be added to the kingdom. This project was so vast and important that it took the world by surprise, It was impossible to deny the soundness of the principles or data upon which it was founded, or the vast importance of it in a national point of view, if means could be found to carry it into effect; but here was one of the great difficulties, and another still greater presented itself, viz., that of uniting together the vast number of conflicting interests concerned, so that they might combine together as one whole body for the completion of the undertaking.

When the plan was promulgated, all kinds of objections were raised against it and attacks made upon it. The affair remained in abeyance for several years, and then it was decided that it would be better to divide the scheme into two parts, one comprising the Ouse and Nene, the other the Welland and Witham. It was next resolved to form a company for the Norfolk half, including the Ouse and Nene, and to reclaim 35,000 acres of land from the Great Wash. Plans were prepared, and in 1846 a Bill authorising the works was carried through Parliament, entitled the Norfolk Estuary Act. But the Company were saddled with so many pecuniary responsibilities that they could not undertake to execute the scheme alone. Consequently the Middle Level Commissioners and the Lynn Corporation, who represented the drainage and navigation interests, agreed to contribute the sum of £60,000 each towards the completion of the new channel for the Ouse, on condition that Robert Stephenson and John Rennie should be joint engineers. This was agreed to; a Bill was obtained, and the works were begun in 1850. They were satisfactorily executed, and the effect on the port of Lynn was so marked that the Corporation were soon enabled to pay off their contribution of £60,000 towards the Norfolk Estuary works. The Estuary Company next turned their attention to reclaiming from the Wash the 35,000 acres which had been allotted to them by the Crown. By slow stages a portion of this large tract of submerged land was recovered, but by no means so much as might have been the case had Rennie's recommendations been followed.

Rennie was next employed by the Corporation of Boston to improve the outfall of the river between the Grand Sluice at the upper end of the town and Hobhole, near the mouth of the river, a distance of nearly four miles. The Witham and Black Sluice Commissioners would not join in the work, however, but as the outfall of the Witham became worse and worse, the Boston Corporation determined to do what they could single-handed. Rennie recommended two reforms which would shorten the navigation quite half a mile, and admit and discharge the tidal and fresh waters more readily, thus deepening the water-line and bed of the river all the way up to the Grand Sluice above Boston. The Corporation acted upon Rennie's advice, and the engineer remarks:

The effect of this work exceeded my most sanguine expectations; in a short time it improved the channel upwards to Boston to such an extent that spring tides rose at Boston Bridge 14 feet, and neaps 10 feet, and the bed of the river was deepened from 3 to 4 feet below low-water springs, so that vessels drawing 15 feet and 16 feet could come up to the town at springs, and vessels drawing 12 to 13 feet could come up at neaps; moreover, all the silt was scoured away from the front of the Maudfoster Sluice, so that it discharged the highland water from the fens, which it had not done for years before, and improved also the discharge of the waters from the Grand and Black Sluices. I must confess that I was not a little elated at this successful result, as it most completely established the correctness of my father's opinion as well as my own, and demonstrated the fallacy of my friend Telford's judgment. The cost of the above works was £33,000, which was very small compared with the advantage obtained. The Corporation of Poston were so much pleased with the success that they determined to carry into effect the remainder of the improvement in the old channel to Boston, which was afterwards done by confining the channel by degrees to a proper width by means of fascines and loose stone and clay properly combined together up to the level of half tide, so that the flow and ebb always acted to the greatest advantage in one and the same channel without materially diminishing the quantity of tidal water.

The effect of these additional works was to still further deepen the bed of the river and increase the flow of the tide by lowering the low-water mark, which improved the navigation and drainage still further, so that the trade of Boston revived and increased in prosperity, and all this was effected by the resources of Boston alone; and it is only to be regretted that the drainage interests, who derived so much benefit, were not compelled to contribute their just proportion.

Rennie further executed minor works for the improvement of the Witham near Lincoln. Also, at the request of the Commissioners of the Ancholme Level consisting of about 50,000 acres of low fenlands, bordering upon the Ancholme in North Lincolnshire — he drew up a series of recommendations for improving the drainage of the lands, as well as the navigation of the river. All these works were successfully executed, and they answered so completely that the Ancholme district is as well drained as any level in the kingdom, while the navigation is complete of the kind.

Railways naturally attracted Rennie's attention as soon as they began to be mooted. He was offered the post of engineer to the Liverpool and Manchester Railway, and with him were joined his brother George and Mr. Charles Vignoles. They made the requisite surveys, choosing the route over Chat Moss. When the Bill for the works was carried through Parliament after great difficulty, Rennie and his co-engineers prepared working drawings and estimates, and naturally expected to be appointed executive engineers. Rennie and his brother were passed over, however, and Stephenson was appointed chief engineer, with Vignoles as resident engineer. The Rennies had designed that the width of gauge should be 5 feet 6 inches from centre to centre of the rail, but Stephenson adopted the old colliery waggon gauge of 4 feet 8.5 inches. It was only after enormous litigation and expense that the 4 feet 8.5 inch gauge was acknowledged to be as much too narrow as Brunel's gauge of 7 feet on the Great Western Railway was too wide. In 1826 Rennie projected a railway from London to Birmingham, and his brother and Messrs. Jessop and Chapman Proposed another from Birmingham to Liverpool, thus connecting three important places, but the scheme was in advance of the time. John Rennie likewise devised plans for two lines from London to Brighton, as well as a coast-line from Brighton westwards, but the period for these also was not yet ripe. Robert Stephenson's line from London to Birmingham was ultimately preferred to Rennie's.

In the year 1822 Rennie was elected a member of the Travellers' Club, and in the following year was elected a Fellow of the Royal Society. He was one of the original members of the Athenaeum Club, and one of the original Fellows of the Royal Geographical Society and the Zoological Society. Some time after the opening of new London Bridge, Rennie went on a short Continental tour. He was in bad health, and still suffering from the effects of a fall into the coffer-dam while engaged in constructing London Bridge. From London he went to St. Petersburg, and visited the Government establishment at Kolpnau for the cotton, gun, and general iron manufactures. He was much interested in finding the latest mechanical improvements adopted here. He also examined the great naval arsenal at Cronstadt, and made suggestions for improvements, some of which were adopted.

With his brother, he afterwards built four iron steamboats, with their engines, for the Caspian Sea, which were the first ever afloat there. They further made the iron gates for the docks of Sebastopol, together with several vessels of war, worked by the screw, for the Baltic and Black Seas. Rennie visited Novgorod, Moscow, and Warsaw, and then returned to England by way of Germany. At this time he lived in a house in Whitehall Place, with his two younger brothers, Matthew and James. Although he was a bachelor, he saw a good deal of society, and was on more or less intimate terms with all the leading authors, painters, sculptors, and men of science of the day.

By the year 1833 Rennie bad completed the London, Hyde Park, Staines, and Cramond bridges; the great naval works at Sheerness, Woolwich, and Chatham; the Victualling Department, or Royal William Yard, and a large portion of the breakwaters at Plymouth, Sunderland, Port Patrick, Donaghadee, and Port Rush; a considerable portion of Kingstown Harbour, the Eau Brink Cut, the Nene Outfall, the Witham Outfall, the Ancholme Drainage, and several other minor works. Rest was consequently necessary again, so he went on a tour through Spain. His party had an encounter with brigands near Cordova, but they reached that city without harm, and then proceeded to Seville. From thence they went to Madrid, and found the capital in a state of the greatest excitement, owing to the vigorous rising of the Carlists under Zumalacarregui. Toledo and Barcelona were next visited, and Rennie returned home by way of Toulouse, Bordeaux, and Paris. On another occasion Rennie visited Austria and South Germany, and at Vienna made the acquaintance of the famous Prince Metternich and the Archduke Charles, Commander-in-Chief of the Austrian armies, who was the first general who defeated the great Napoleon at Aspern.

Rennie examined three alternative routes for a ship canal from London to Portsmouth, and he regarded the canal as perfectly practicable, though it was doubtful whether it would ever have made a sufficient return upon the capital. The undertaking was not carried through, and railways have since rendered it unnecessary. The machinery manufactory founded by the elder Rennie was carried on by John and George Rennie, who constructed the rolling mills for the Calcutta and Bombay mints; machines for Deptford, Portsmouth, and Cremill Point; locomotive engines for railways, steam-engines and machinery for English and foreign vessels, etc., etc.

In 1832 Rennie made complete hydrographical surveys of all the harbours in the Isle of Man, and suggested plans for the hest way of improving them, some of which were carried into effect. He further improved the port of Hartlepool, and the mouth of the Coquet, near Warkworth, and constructed the piers of Sunderland Harbour. During 1837-38 he was again occupied with the Brighton railway scheme, which he carried through, as well as the Blackwall Railway. All through the time of the railway mania his labours were most arduous, as his advice and aid were sought in connection with a multitude of schemes. His alternative plan for the Great Northern line, which was acknowledged to be superior to that adopted, was unfortunately thrown out of Parliament. Another important line lost was the Bristol and Chepstow, which would have materially shortened the distance between Bristol, Birmingham, and Liverpool, and have enabled the South Wales Railway also to shorten materially their distance to London. A scheme for a Central Kent Railway line likewise fell through, though the South Eastern Company admitted it to be better than theirs for Kent and the sea-coast, and the landed proprietors who opposed it subsequently repented of their action. The South-Eastern were compelled to expend nearly £700,000 to cut of the angle between London and Tunbridge, all of which might have been saved by the adoption of Rennie's plan, while under the same plan there would have been no necessity for that expensive line, the London, Chatham, and Dover.

On three occasions Rennie visited Sweden with the object of constructing railways. He made elaborate surveys, but the Swedish Government were apathetic, and they would give no guarantee, although they had made a concession to Count Adolphe Rosen, who offered half of it to Rennie for his services. Says Rennie -

Accordingly, the Swedish railways remained in abeyance until the year 1852; by this time the Swedish Government had considered the subject maturely, and felt that, as every other European nation had adopted them, Sweden, if she desired to keep pace with other countries, must either make the railways herself, for which at the time the Government had not the money, or she must encourage others to make them by guaranteeing a sufficient interest for the capital expended.

Accordingly I went there again, and was as usual very kindly received by the King and his Ministers, and I saw that they were becoming more anxious than ever that the railways should be made. I had been there in October, 1848, and had the honour of being invited to dine at the palace in Stockholm, as I had previously the honour of dining with their Majesties at the summer palace of Hoga, near Stockholm. Upon arriving at the palace, I was most courteously received by King Oscar, who did me the honour of presenting me to his handsome, graceful, and intelligent Queen. When her Majesty heard that the railways were to be commenced, she said that she heard so much talk about them and nothing had been done, that she feared they never would be made, "therefore talk no more about them, but set to work and make them."

The dinner-party consisted of about thirty. I had the honour of sitting next the Lord Chancellor, a very agreeable, intelligent person, who sat next to the Royal Family. We had an excellent dinner, without the least restraint, and the common topic of conversation seemed to be, who would be elected President of the French Republic, Cavaignac or Louis Napoleon, and everybody seemed in favour of Cavaignac as the proper person; they all spoke disparagingly of Louis Napoleon. It seems curious to think how little the world knew of that extraordinary man, and how completely he disappointed all previous expectations.

When at Stockholm I was presented to his present Majesty, King Charles XV., then Prince Karl, a very handsome, intelligent young man. Since his accession to the throne he has done me the honour of conferring upon me the order of Knight Commander of the Order of Wasa, for what his Majesty was pleased to term the great services which I had rendered Sweden. This was the more agreeable, as it was sent to me through my personal friend Count Platen, then the Swedish representative at the Court of London.

In 1852 the concession for the Swedish railways was renewed, with a Government guarantee of four per cent on the amount of capital required, viz., £420,000, with power to raise £167,000. Rennie went over to Sweden again: the works were begun, and everything was going on well, when the Chairman of the Company, the notorious John Sadleir, M.P., committed suicide, and his fearful mismanagement of the Swedish railway and other undertakings was fully exposed. Rennie resigned his post of engineer, and it was well he did so, for things were carried on in a discreditable manner, and as a man of honour he would have nothing whatever to do with the whole concern. In the hands of an honest body of directors the Swedish lines would have paid well.

In 1852 Rennie acted as engineer to a Belgian and English company formed for the reclamation of tracts of land on the Scheldt. He had here to complain of the enormous waste of money and labour, some 1,300 men being engaged at from 3s. to 4s. per day, who were not doing half the work they were engaged for. The scheme also of endeavouring to reclaim 3,000 acres of land at once he saw to be impossible, and after great difficulty he persuaded the contractors to reclaim by smaller portions, which was successfully done. Rennie was strongly of opinion that the whole of the sea-board of Holland required to be re-modelled. If all the superfluous channels were filled up, and the islands which they surround were united to the mainland, a great quantity of valuable land would be gained to the State.

Rennie went to Portugal in 1855, at the request of the Government, to make arrangements for a general system of railways and other works. He was cordially received by Dom Fernando, husband of the late Dona Maria, Queen of Portugal, and brother to the late Prince Consort. Rennie inspected the great aqueduct of Lisbon, which he regarded as a grand and magnificent work, the finest of the kind in Europe. He was also much interested in the Castle and Cathedral of Belem, the latter of which buildings was erected in honour of Prince Henry, the Portuguese navigator.

At the request of the Government he prepared plans for docks or landing jetties for the port of Lisbon. He thought the harbour the finest and most spacious in Europe, always excepting that of Vigo. Next he went to Oporto, where he carefully examined the port, and found that, owing to a variety of causes, the harbour of Oporto was hermetically sealed for three-fourths of the year. Vessels had been known to go to the Brazils and back, while others were waiting in the offing for a favourable opportunity to cross the bar. Then the mails for Oporto, the second city in the Kingdom, had frequently to be delivered at Vigo, sixty miles further north, and to be there transported by land. To remedy the defects, Rennie drew up a plan for erecting two piers at a cost of £400,000 — one on the ridge of rocks on the south side, and another on the north — in such a direction that the entrance between them, which was to be 500 feet wide, should be least exposed to the prevailing storms. These works would have been a great improvement, and well worth the money, but as the bar would still be unapproachable on certain occasions, the engineer cast about for a site for a new harbour, and found an excellent one at Mattozenhas. As fine granite was cheap and plentiful, he considered that for a sum of £500,000 an admirable harbour might be made here with a double entrance. He therefore strongly recommended it in preference to expending £400,000 on the old entrance.

The King and the Government approved the plans, and the Finance Minister Fontes gave orders for the works to be begun immediately. Shortly afterwards, however, there was a change of Ministry, and the whole arrangements fell to the ground. Rennie afterwards examined the harbours of Viana and Figuera, and reported upon them. When Dom Pedro had attained his majority, and ascended the throne, he invited Rennie to visit Lisbon again, feeling convinced that until her railways, harbours, and docks were placed on a proper footing, Portugal could never take her proper place among the nations. Rennie accordingly went over with his harbour plans and reports, and made further surveys through Portugal with a view to the construction of railways. Several important lines were begun, including one for a better and more direct communication with Spain; but disputes arose between Messrs. Peto, Betts and Co the contractors, and the Portuguese Government, which terminated in the abandonment of what would have been for Portugal a great national work.

Rennie subsequently visited Tunis in company with one of Messrs. Peto and Betts's agents, to examine into the feasibility of constructing a railway from the Goletta to the city. The requisite survey was made, but owing to the imprudent action of the contractors' agent, the French Consul became alive to the whole situation, and in an audience with the Bey threatened him with the vengeance of France if the concession were granted. The Bey was obliged to submit, and the project was abandoned.

I may pause here to note Rennie's chief contributions to the literature of engineering. He wrote a pamphlet on the Drainage of Lombardy which attracted the practical attention of the Italian Premier, Signor Sella. One of his papers contributed to the Institution of Civil Engineers upon the 'Harbour of Ostia' was full of instructive practical facts relating to the effect of the action of tides and of rivers in the formation of deltas, shoals, and bars at the entrances of harbours.

His presidential address to the Institution of Civil Engineers in 1846 was practically a condensed history of the rise and progress of engineering science in modern times. In 1847 he published a monograph on Plymouth Breakwater. But his most important contribution to professional literature was his work on The Theory, Formation, and Construction of British and Foreign Harbours. It was dedicated to the Queen, and was published in two volumes in 1854. In addition to being a survey of larger engineering works, this treatise included descriptions of the docks constructed by Rennie at Whitehaven for Lord Lonsdale, and the extension of the Cardiff Docks which he carried out for the Trustees of the Marquis of Bute. Rennie was admitted to be the highest authority on all matters connected with hydraulic engineering, harbours, canals, drainage, irrigation, the storage of water, and the management of rivers. It may be added that he greatly contributed to the introduction of Sir Francis Pettitt Smith's invention, the screw-propeller, into the Royal Navy.

Rennie was called upon to make an official report on the condition of the city of Odessa, which seems to have been the worst city in the world as regards paving and sewers. There was, in fact, neither one nor the other, and people living only one mile from the food supplies and the butchers' shops were practically starved at certain seasons of the year. The engineer's recommendations had a salutary effect. Then he was asked to examine the water-supply of Vienna, which he found to be most defective. He made investigations in the vicinity, and having found a source whence a good water-supply could be obtained, he drew up a report to the municipality of Vienna. That sage body thanked him for it, and then spent many years in fruitless discussions as to whether they should carry out his recommendations.

In 1861 Rennie constructed for the Portuguese Government the harbour of Ponta Delgada, the chief town in St. Michael's, the principal island of the Azores. He next carried out additional improvements in Ramsgate Harbour, in regard to which he occupied the post of principal permanent engineer. After the harbour was transferred to the Board of Trade, he still continued in his old post, and at the same salary, viz., £315 per annum and travelling expenses. He then turned his attention to constructing the Dagenham Dock, on the left bank of the Thames, utilising the Dagenham Lake, a fine sheet of water, for the Purpose. He made considerable progress with the works, and something was done towards converting the lake into a great dock establishment, but although several Acts of Parliament were obtained, the works could not be completed under Rennie's plans, and they fell into abeyance.

Sir John Rennie took a high view of his profession. Here is what he wrote on this subject towards the close of his Autobiography.

The real object of the civil engineer is to promote the civilization of the world, by the proper application of the great mechanical means at his command, and to take a high independent position as a scientific man, thoroughly versed in his profession both theoretically and practically, and wholly independent of contractors, and all sinister influence. Unless he can do this, he never will be held in that esteem and respect, or take that high position without which no professional man can properly discharge his duties that he owes to himself and to the public.

Against what I have said it may perhaps be urged that I assign too high a place to the profession to which my father and myself have had the honour to belong; but I think that when the subject has been calmly and fairly considered it will be generally admitted that I have not done so without reason. Without wishing for a moment to depreciate the merits of any other body of men, I think it will be conceded that the objects proposed by the engineer, and the acquirements, knowledge, and experience that he must possess before he can practise successfully, are at least equal to those of any other profession, particularly after the practical examples exhibited to the world of the great benefits that engineering has already conferred upon mankind. Therefore are we entitled to be ranked amongst the most learned professions, and to receive all the honours they have most justly earned; and I trust the time is not far distant when this justice will be accorded to them.

With regard to the proper training for a civil engineer, Rennie observes:

Let him first get a sound elementary education in the several departments of arithmetic, algebra, geometry, natural philosophy, geography, geology, astronomy, chemistry, land and hydrographical surveying, as well as grammar, English composition, history, French, German, and Latin, according to the improved system of modern education; every youth of ordinary talents his a tolerably fair knowledge of these at seventeen or eighteen. What then should be the training for an engineer? First let him go through the best course of modern education at his command, including the elements of geometry, mathematics, and the physical sciences, not excluding Latin and Greek, in spite of the prejudice against them now frequently expressed. Then let him be apprenticed for two or three years to some good steam-engine and machinery manufacturer, where he should learn to make drawings and calculations, handle tools, make models, steam-engine machinery, and put machinery together. By this means, if he applies his mind to it properly, he may become a practical as well as theoretical mechanician, which is the soundest basis for good engineering; indeed, without this it is impossible for an engineer to be thoroughly successful, but being well grounded in this most important knowledge, all the others will become comparatively easy. Having gone through this apprenticeship, let him bind himself for three or four years to some well-known civil engineer, of large practice in railways, docks, harbours, waterworks, canals, drainage, rivers, etc. In this office the pupil will learn everything connected with these departments, and as they are founded more or less upon practical mechanics, he will soon find that from his previous mechanical education he has already acquired considerable knowledge of them, and it will only be necessary to apply those principles, modified according to the particular circumstances required; in fact, the principles are the same, although applied upon a larger scale.

The practical instructions which Rennie gives to civil engineers in concluding his Autobiography are invaluable, even in the light of the advances which the science of engineering has made since they were written. They range over such topics as the construction of harbours and canals, drainage, the water-supply of towns, the storage of inflammable goods, docks and warehouses, embankments, breakwaters, bridges, etc.

It is cheering to find a veteran writing as follows, after an experience of human life extending over a period of upwards of seventy years:

The motto of life should be, "Forward!" We must expect to be checked, thwarted, and baffled in our endeavours to obtain success; but these obstacles, instead of totally arresting our progress, should serve only to increase our energy. Like a river, impeded in its course, in silence waits till its accumulated strength sweeps the obstruction from its path, and it flows on majestically as before — so should we make every difficulty we encounter add to our strength, instead of increasing our weakness. Nevertheless, since "'tis not in mortals to command success," we may sometimes struggle in vain; and fortune ever against us, we may be overcome at the last; but even then we have this satisfaction — we have fought a good fight; we have done the best we could; we have done our duty to the best of our ability, and this is all that can be required, of us.

To do my duty has been my endeavour through life; and probably if I had adhered to it more strictly I might have done a great deal better. Nevertheless, little as I have done, I should not have accomplished half so much, had I not kept that one object in view, as far as my physical and mental powers would permit; and this is no small consolation. The old motto "Nil desperandum," should be constantly on our lips, and should act like the spur on a jaded steed. Affairs are never so bad but they might have been worse, and they may generally be mended by energy and perseverance, and a determination to make the best of everything. We may not be able to accomplish all we desire to achieve; nevertheless, by refusing to yield to misfortune we shall escape the reproach of cowardice and faintheartedness. When we suffer a defeat, let us calmly consider the cause of it, and nine times out of ten we shall find it is through our own fault; these lessons of experience should be carefully laid to heart, and serve for our future guidance.

I have never deemed wealth desirable for mere personal gratification, but only in so far as it would have enabled me to help others, to promote the advancement of science and the well-being of my fellow-creatures; this would have conferred the greatest happiness upon me, but it has been denied by the Almighty Disposer of events, and most probably with justice, that it might he done better by other hands. I therefore humbly bow to the Almighty's decision; and if I have done the best I could in His sight, I am amply rewarded. I, however, most deeply regret that I have not done more. I return my most fervent thanks to the Almighty that He, out of His great mercy, has allowed me to do the little I have done; and I most devoutly hope that He through His Son Jesus Christ will pardon my shortcomings; and I say with all reverence, Bless the Lord for all His mercies.

Sir John Rennie contemplated writing a history of engineering — enlarged from his address to the Institution of Civil Engineers — as well as a Life of his revered father, but he did not live to accomplish either of these works. After the year 1866, he undertook scarcely any professional labours, though he lived for eight years beyond this time. He had just completed his eightieth year, when he passed away, on the 3rd of September, 1874, Rennie's was a full, useful, and valuable life, and it worthily carried forward the traditions he inherited from his father. In both these men there was a lofty spirit of enterprise and an indomitable will, and we can give equal honour to both for those magnificent works which have added so much to the material prosperity and glory of England.

See Also

• Leaders of Modern Industry by G. Barnett Smith
• J. and G. Rennie
• John Rennie (the elder)
• John Rennie
• George Rennie