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Note: This is a sub-section of 1892 Institution of Mechanical Engineers
Visits to Works (Excursions) in the Portsmouth and Southampton area
H. M. DOCKYARD, PORTSMOUTH.
On entering the Dockyard by the main gates A, Plate 33, from what is known as the Common Hard, Portsea, on the left just within the gates are the mast-houses. Prior to the days of steam navigation, and to the manufacture of iron and steel masts, the work carried on within these buildings afforded unfailing interest to all who were capable of appreciating the construction of the masts and spars for the old battle-ships. At the end of the mast-houses, and a short distance to the west, is a building B containing the principal engines for the hydraulic service of the dockyard. From this point are seen two long rows of brick buildings, one surmounted about the middle by the clock tower C, and the other by the semaphore D. The clock-tower buildings are the storehouses, in which cordage, sails, light metal, and other goods are kept for supplying to the ships of the navy. The semaphore building contains the sail loft, the colours or flags loft, and the rigging house. Before the days of the electric telegraph, information was signalled from this semaphore to similar apparatus on the hills at the north of the town, and thence principally to Whitehall; and so complete was the system for the transmission of messages from semaphore to semaphore, that it is said any signal made from a ship arriving at Spithead was in the hands of the Admiralty in half an hour. As fogs sometimes interfered with the communication to the next station, horses were kept saddled and bridled ready to convey a message. Daily at one o'clock the fall of the time ball at Greenwich was communicated to Portsmouth; and as the semaphores were ready for the message, it commonly passed from London to Portsmouth in less than half a minute. The last message transmitted by this route and system was on 31st December 1847. From this elevated position a splendid view is obtained of the dockyard and harbour, the Solent and Spithead, and the whole of the adjacent towns.
Almost opposite to the clock tower C is Anchor Lane, which is filled from end to end with a double row of anchors piled closely together. It runs between a row of storehouses on the south side, built in 1777, and the old rope house E on the north side; the latter also is now used as a storehouse, the manufacture of ropes having been discontinued at Portsmouth. A little further north is the Admiral Superintendent's office F, fronting No. 2 dock, in which Nelson's ship, the " Victory," was recently repaired, and thereby obtained a fresh lease of life.
The bridge of No. 2 dock is near the centre of an almost quadrilateral area of just over 8 acres, which formed the original dockyard in 1540 during the reign of Henry VIII, Plate 32. During the Commonwealth 2 acres were added in 1658 on the east side; and during the reign of Charles II there were added 18 acres, 8 in 1663 on the south side, and 10 in 1677 on the east. William III added 101 acres on the north side, beginning what was apparently the first reclamation of mud land, the northern boundary of the previous area having been the shore line. The reclamation then begun appears to have been completed in 1710 during the reign of Queen Anne. In 1723 George I extended the reclamation in the same northerly direction, adding 19 acres. In 1790 George III completed the northern portion of the yard by a further addition of 5 1/2 acres. On the south and south-east sides of the dockyard a line of fortifications appears to have existed, which were afterwards demolished; and in this direction land was from time to time added to the yard, until the southern part extended up to the existing boundary wall built in 1711, in which the main gates are situated. From 1793 to 1843 there appears to have been no alteration in the boundary of the dockyard; but on the introduction of steam, navigation increased accommodation was required, and in 1843 a purchase was made of 5 1/2 acres of property, and about 12 1/2 acres of mud land were reclaimed; this part of the yard was completed in 1848. In 1864 was commenced the work now known as the Dockyard Extension, which included the absorption of about 84 acres of land occupied chiefly by old fortifications, and the reclamation of about 93 acres of mud. This extension gives the dockyard at the present time an area of altogether about 293 acres.
From the bridge of No. 2 dock the old ship basin of 2 1/2 acres, Plate 33, and the docks in connection therewith, are all within sight, the dock gates and bridges affording evidence of a past era. Two of the docks, Nos. 3 and 4, have been modernised by being fitted with caissons, and have also been lengthened. The masonry at the entrance to the basin bears the inscription " Britannia, 1801." At that date, under the direction of General Bentham, the entrance to the basin was reconstructed and fitted with a caisson, the first which had been made in England; and it is stated that at its first use a large number of people assembled, mostly incredulous of its success. It is assumed from the inscription that a ship named " Britannia " was the first vessel to pass through.
At the end of the bridge of No, 5 dock is situated at G the oldest dock-pumping machinery in the yard. Adjoining are the blockmills and sawmills H, where is to be found the complete set of block-making machinery designed by the elder Brunel in 1801, and manufactured by Messrs. Maudslay. The value of this machinery at the time it was erected may be judged from the fact that the price agreed to be paid for the design was the amount of the savings on one year's requirements of blocks for the navy; and this was estimated to amount to £16,621. Brunel was also paid £1,000 for his models, and a retaining fee to inspect the manufacture of the machines, making a total of £20,000. The dock pumps were renewed at about the same time, and the first steam engine was erected in the dockyard; this improvement was carried out by General Bentham, who also started the sawmills. Northwards are Nos. 7 and 10 docks, which by the removal of a caisson can be made into one dock 648 feet long. This is the longest dock in the establishment; and it appears from old plans to have been a natural creek, once known as the North Camber.
Northwards of No. 10 dock are the ship-building slips, of which there were five. In the days of wooden ships and less dock accommodation, all five were required for building purposes; but at the present period of iron shipbuilding, it is found convenient to utilize some of them as machine shops, &c. On the northernmost slip, known as No. 5, is being built the "Fox," intended for a cruiser of 4,360 tons displacement and 9,000 I.H.P. with a speed of 19 1/2 knots. One of the last of the old wooden line-of-battle ships, the "Victoria ". of 121 guns, was launched from this slip by Her Majesty in 1859, at which date each of the five slips had a ship building upon it: on No. 4 was the "Duncan," a two-decked ship; on No. 3 the "Prince of Wales," a three-decker; on No. 2 the "Frederick William," a two-decker; and on No. 1 a frigate.
The next point of interest is the west steam factory, Plate 33. In the boiler shop J at the northern end the boilers for the " Fox " are at present cinder construction. At the southern end of this shop are the turnery and the erecting shop, where are in course of construction parts of the engines for the " Fox," besides several submerged discharging tubes for Whitehead torpedoes. The upper floor over the whole 600 feet length of the building is used for light fitting work. Close at hand is the smithy K, with its furnaces, steam-hammers, forging machines, &c.; this building was partly constructed of materials from the Exhibition of 1851. Crossing the caisson of No. 7 dock, and passing along the south side of the steam basin, on the right are the offices L of the Chief Constructor and the Chief Engineer. Continuing round the steam basin, which covers an area of seven acres, on the east side are the 40-ton sheers and the 40-ton steam crane. At the head of No. 11 dock, which opens out of the steam basin, is situated the centrifugal dock-pumping station M; south of this is the shipbuilding shop N, eastwards of which at a little distance is the gun-mounting store and workshop P. Northwards again, at the south-west corner of the repairing basin, are the boiler house Q and the engine house R of the central pumping station, which last contains also the air-compressing machinery for the yard service. On the south side of the repairing basin is the electric fitting shop S; and further east No. 13 dock, in which is building the second-class battle-ship " Centurion," of 10,500 tons displacement, 13,000 I.H.P., and speed 181 knots. From the stern of this vessel the torpedo store T is about 300 yards to the south-east. On the east side of the repairing basin are the 80-ton sheers U. Outside the north wall of the fitting-out basin are three of the old wooden line-of-battle ships, "Asia," "Duke of Wellington," and "Marlborough," now used as barracks for seamen. At the western extremity of the fitting-out basin is "Coaling Point," now being completed and fitted with hydraulic coaling machinery by Messrs. Tannett Walker and Co.
Passing over the sliding caissons Z which connect the north and south locks and the deep dock with the tidal basin, a good view of the four basins and their appliances can be obtained. The greatest depth of water over the dock sills is 41 1/2, feet, and the length of the docks here is 415 feet. Of the three enclosed basins one covers an area of 22 acres, and the other two of 14 acres each; the tidal basin covers 10 acres. The whole of the gear for the capstans, penstocks, and some of the cranes belonging to these docks and basins, and also the sliding caissons, are worked by compressed air.
For returning hence towards the main gates the route leads past the foundry V, the pattern shop, the joiners' shops, and also the residences of the principal officers and of the Admiral Superintendent.
At the end of the terrace of houses on the east is the fire-engine house W, surmounted by a tank containing 770 tons of water, which is used for supplying injection to the condensers of the various engines, as well as for fire-service purposes. Opposite is the chemical laboratory, and further on are continuations of the storehouses on each side. After passing through an arch, a little to the east is the dockyard church; beyond which, along the main road, is Admiralty House on the east side, the residence of the Naval Commander-in-Chief, and on the west the dockyard lawn with officers' residences. The latter originally formed the naval technical school presided over by the late Dr. Woolley. Many of the buildings in this part of the yard are said to have been erected under the supervision of Telford, who was employed as foreman of works at Portsmouth from 1784 to 1780; and he relates that while here "he had frequent opportunities of observing the various operations necessary in the foundations and construction of the docks, wharf- walls, and such like." After passing the Commander-in-Chiefs house, on the east is the Royal Naval College, and the naval savings bank with the cashier's offices; and on the west are the boat-houses, opposite to the mast-houses, and close to the main gates of the dockyard.
This establishment, of which a plan is shown in Plate 64, exists for the supply of provisions, victualling stores, and clothing to the seamen of the Royal Navy on the Portsmouth station, and for the supply of provisions and victualling stores required by troops voyaging on Indian and Imperial services; that is to say, the supplies here dealt with are those which relate to the personal sustenance and comfort of the crews, as distinguished from those which form the stores for the equipment of the ships themselves apart from their crews. For the supplies of fresh provisions, such as fresh beef, mutton, corned pork, &c., ample accommodation has been provided in the shape of extensive lairs and abattoirs, constructed and arranged on the principles approved by the Agricultural Department, one of the main objects being to secure the inspection of every animal in a live state, as a preliminary evidence of health and quality. The animals are then stored for not less than a minimum period, in order that they may become tranquillized before slaughter, as this condition is also important for the healthfulness and keeping properties of the meat. The quantities issued of fresh provisions are large, as in this respect the Victualling Yard provides not only for the seamen afloat, but also for the troops and marines in garrison, representing daily rations in the aggregate for some 15,000 men in ordinary times, and for much larger numbers in times of pressure, such as reviews, mobilisations, expeditions, &c. There is also an extensive granary, a flour mill, and a biscuit bakery. Wheat is purchased under local contracts, and converted into flour and biscuit according to requirements. For some years past there has been a progressive diminution in the demands for biscuit, owing to the shorter periods during which the ships are now at sea, and to the introduction of soft bread baking on board troop ships and depOt ships &c.; hence the bakery machinery, which works economically and efficiently, remains practically what it was on its first introduction more than forty years ago, pending improvements which experience of the precise wants may ultimately show to be most suitable. Casks and cooperage utensils of all descriptions are manufactured on the premises by hand. There are also extensive storehouses for every description of provisions and clothing, water tanks, officers' and seamen's mess traps, miscellaneous implements for use on board ship, &c. The establishment further supplies water from its reservoirs for victualling purposes on board ships, to which it is delivered by the steam water-tanks belonging to the yard. A private railway station in this yard has been used by Her Majesty for many years on her journeys to and from Osborne.
The Southampton Docks, Plate 65, are 78 miles west-south-west from London by the London and South Western Railway. This port enjoys the advantage of double tides, a peculiarity met with at no other port. In addition to the usual high water, a second high water occurs here about two hours after the first, in consequence of the Isle of Wight being situated across the entrance to Southampton Water. In the progress of the great tidal wave up the Channel, the portion flowing up the Needles passage into the Solent becomes separated from the main body of the wave, and reaching Southampton causes the first tide here at about the same time that the main flow arrives at Dunnose Head, the south-easternmost point of the island. This first tide on beginning to ebb from Southampton is stopped and driven up again by the main stream coming round through Spithead, and thus producing the second tide at Southampton about two hours later and six inches higher than the first. Low water is about three and a half hours after the second high water, or about five and a half hours after the first; and the flood tide lasts about six and a half hours. To ships using the port it is obviously of great advantage to have the water thus remaining nearly stationary at high tide for more than two hours, thereby allowing vessels to come out of the graving docks without risk, and others to enter without losing a tide. The docks are situated in a remarkably safe position within the land-locked port, and are accessible at all states of the tide and in all weathers.
The southernmost dock is the Empress Dock, which was inaugurated and named by Her Majesty the Queen on 26th July 1890. Its extent is 18 1/2 acres, with a minimum depth of 26 feet at low water of spring tides, and an entrance 175 feet wide. It is provided with 3,750 feet of quays, and extensive cargo sheds of the most complete description. Owing to the peculiar rhomboidal or lozenge shape of the dock, vessels can be berthed alongside any of the quays without being turned, and with the greatest amount of ease. It has also been possible to lay the rails round the quays so that there is no curve of less radius than six chains or 400 feet, which has been found a great convenience for passenger traffic, as railway carriages can thus be taken to any part of the dock.
Further north is a tidal basin of 16 acres, with an entrance 150 feet wide, and a depth of nearly 31 feet at high water of spring tides. Adjoining the basin on the west side is a close dock of 10 acres, with 56 feet width of entrance, and a depth over the sill of 29 feet at high water of spring tides, and 25 feet at neaps. The length of the quays exceeds 7,500 feet; in addition to the extension quay 1,820 feet long, with 20 feet of water at low tide, which forms the eastern arm of the Empress Dock.
The four dry docks are capable of taking vessels of 8,000 tons and upwards. The following are their dimensions in feet
|Dry Dock||Length||Width||Depth of Water|
No. 2 dock was the first dry dock ever built of brick, previous dry docks having invariably been built of stone. There are three sets of sheers, worked by steam power, for lifting up to 100 tons.
UNION STEAMSHIP COMPANY'S NEW REPAIRING SHOPS, SOUTHAMPTON DOCKS.
Union Steamship Co
The buildings are arranged in two parallel blocks, Plate 66, each 2391 feet long by 49 feet wide. The north block is 331 feet clear height from ground level to under side of principals; and is well lighted from large side windows and skylights extending the whole length of the roof. It is divided into fitting and machine shops, engine and boiler house, and boiler-makers' shop. A 20-ton overhead hand-travelling crane, arranged to traverse the whole length of this block, is erected on piers 26 feet above floor-level, thus giving ample head-room for lifts. The main shafting, for driving lathes, radial drilling machines, punching and shearing machines, plate-bending rolls, etc., is carried on brackets secured to piers on one side of the building, and the counter-shafting is carried on double steel beams underneath of H section. The engine and boiler house contains two marine boilers, one compound engine for driving the machinery, a Cameron donkey-pump, and one Haslam cold-air machine delivering 20,000 cubic feet of cold air per hour.
This machine is arranged to work two cold chambers, of 2,233 and 2,194 cubic feet capacity, which are built outside of the north block. The temperature of each chamber is continuously indicated upon a thermometer scale fixed in the superintendent's offices. In the boiler-makers' shop is a large plate-heating and annealing furnace, capable of admitting a plate 12 feet by 6 feet. In this shop are also placed a Root's blower for supplying blast to smiths' fires, a heavy punching and shearing machine, plate-bending rolls, etc.
The south block is only 20 feet high. It comprises pattern, tinning, and tinsmiths' shops, brass foundry, coppersmiths' and blacksmiths' shops, and stores. In the smiths' shop there are two steam-hammers of 12 and 4 cwts.
At the east end of the north block are placed the time offices and general stores. At the west end are the superintendent's offices on the ground floor, above which is a spacious drawing office; and above this again a photographing room, fitted with a novel arrangement for launching out frames for sun exposure.
In the yard of 30 feet width between the two blocks, rails are laid in connection with the dock service, having two large turntables to facilitate getting heavy pieces of machinery into the fitting and boiler-makers' and smiths' shops; when brought under the overhead traveller in the north block the pieces can be manipulated at will. Throughout the yard ample provision is made for extinguishing fire, several hydrants being conveniently arranged, and fitted with hose in cases, ready at any moment for use. An important feature in this factory is the telephone arrangement from the superintendent's offices to all the various departments, whereby full communication with foremen is obtained without loss of time.
ORDNANCE SURVEY OFFICE, SOUTHAMPTON.
The manuscript plans completed at any of the ten Ordnance Survey Offices throughout the country are sent to Southampton for publication on the following scales:- 10.56 feet per mile, or 1-500th, for maps of towns of which the population exceeds 4,000; 5 feet per mile, or 1-1,056th, for maps of certain towns; 25.344 inches per mile, or 1-2,500th, for parish maps; 6 inches per mile, or 1-10,560th, for county maps; and 1 inch per mile, or 1-63,360th for a general map of the country. Town maps were originally engraved on copper, but are now published by photozincography, as are also the parish maps. Many of the six-inch county maps have been engraved on copper, and the process is still used for some counties. The manuscript plan, scale 1-2,500th, having been reduced by photography to the scale of six inches per mile, the photograph is traced on special tracing paper with a composition of lamp-black and gum and water, and the tracing is rubbed down upon a copper-plate, covered with a thin film of wax. The work is then engraved on the copper-plate, and printed for publication.
From about 1881 to 1890, for the cadastral survey, the six-inch maps were produced direct from the 1-2,500th manuscript plans by photozincography. To suit this process, all the detail in the manuscript plan is drawn to scale; but the names and ornament are sufficiently enlarged, so that when reduced they will be of suitable size. Moreover any names or ornament that would crowd the detail too much on the reduced scale are drawn on the manuscript plan in cobalt blue, and hence are not reproduced by photography. After the photographic transfer has been laid down on the zinc plate, the parks and also the mud along rivers, sea coasts, &c., are inserted by a tint. This is done by applying an etching solution wherever the tint is not required; after which, finely ruled lines can be transferred to the unetched portions of the zinc plate to produce the tint required. The advantages of the process are, firstly that the work is more accurate, any possibility of error in reduction being eliminated; secondly the operation is so much quicker that a plan which took two years to engrave can be produced in two days; thirdly there is a great saving in cost, estimated to exceed £100,000 on the total work.
In the case of the plans of Lancashire and Yorkshire now being published, the 1-2,500th manuscript plans are not specially drawn for reduction to six-inch scale. In this case impressions from zinc printed in cobalt blue are inked by pen in black, with such thickness of outline and size of lettering that when reduced they will produce the size required for the six-inch scale. Everything tending to overcrowd the detail on the reduced scale is left in cobalt, and is consequently not reproduced by photography. The four 1-2,500th impressions that are to form the six-inch quarter-sheet are then placed together, and the common edges made to fit accurately, and the whole is reduced by photography.
A reduction to the one-inch scale is made from the six-inch map, only so much of the detail being reduced as can be shown on the one-inch map without impairing its distinctness. A tracing of this is laid down on copper and engraved. The old process of producing the one-inch map was by a pentagraph reduction from the six-inch sheets; but the pentagraph has now been dispensed with, and such of the detail as is intended to appear on the one-inch scale is inked by pen in black, on blue impressions of the six-inch sheets; the remaining detail being left in blue is not reproduced by photography. The impressions are reduced by photography and transferred to zinc, from which a print is taken in transfer ink for rubbing down on copper for engraving. As soon as the engraving is completed for the outline edition, which shows contours and all other detail except hill-shading, a matrix is taken of the plate, and a duplicate plate made from it, and used for printing copies for sale. The hill features are engraved as a separate plate, partly by a graver and partly by etching, and a matrix and duplicate are then made. The main difficulty in engraving the hill features is to keep the different ranges of hills in proper subordination. The copper-plate printing press is a powerful one, being arranged to give a pressure of 40 tons on the cylinder, and the driving power is obtained from a small high-speed Willans engine, geared direct by means of a worm wheel. A second steam printing press has recently been erected.
The electrotype process, which is eminently suited for reproducing engraved copper-plates, was adopted on the Survey first at Dublin in 1840, one year after its discovery; and then at Southampton in 1847. By this means a matrix, in which all the detail is raised above the surface of the copper, is obtained from the original engraved copper-plate, and from the matrix is made a facsimile or duplicate of the original. This duplicate is used for printing from, and it can be reproduced from the matrix when signs of wear are apparent, usually after about 700 impressions have been pulled. The saving effected is great, for whereas an original engraved six-inch plate costs on an average £300, the cost of reproduction by electrotyping is only £6 or £7. The process is also used for taking copies of an engraved copper-plate map at different stages, for making corrections; and also for reproducing the stamps of trees, woods, &c., used in stamping the ornament on the manuscript plans.
The electrical current is obtained from a shunt dynamo by Messrs. Crompton and Co., and driven direct by a Willans three tandem compound high-speed engine, the current being kept constant at 35 amperes by means of a Willans electrical governor. The dynamo is connected to a number of electrolytic tanks by means of copper-wire leads. These tanks contain a solution of sulphate of copper slightly acidulated with sulphuric acid, and they are arranged in series, that is to say the whole current from the dynamo passes through the first tank, then through the second, and so on through all the tanks, 23 in number; and then through the solenoid of the electrical governor, finally returning to the dynamo. The connections are so arranged that any of the tanks can be cut out of the circuit at pleasure. A rocking motion is given to the tanks to keep the solution at a uniform density. At night the current is supplied from accumulators made by Messrs. Elwell and Parker, which are charged in the daytime by the dynamo; the rocking motion is caused by an electric motor driven by five of the storage cells. The engraved plate, after being chemically cleaned, is washed over with cyanide of silver, and afterwards with a solution of iodine in alcohol, and is then exposed to the sun for a few hours, the object being to prevent any of the deposited copper from adhering to the plate. It is then secured to a board, and the edges are covered with is composition of beeswax and tallow to prevent the copper from growing over the edges. A sheet of commercially pure copper, called the dissolving plate, is placed in one of the tanks, and the engraved plate is placed over it, being separated from it and kept parallel to it by means of wooden blocks. Electrical connection is then made to the leads that carry the current, by means of two short leads of twisted copper wire, soldered respectively to the dissolving sheet and to the engraved plate. As soon as the connection is made, electrolytic action commences, which causes copper to dissolve from the dissolving sheet, and to be deposited in equal quantity on the engraved plate. On a full-sized engraved plate it is deposited at the rate of one-tenth of a pound per hour. The smaller plates are electrotyped in a vertical tank. As soon as a matrix has been produced of 1-12th inch thickness, the engraved plate is removed from the trough, and the matrix separated from it. When a duplicate is required to be electrotyped, the matrix takes the place of the engraved plate, and the above process is gone through: except that, as the duplicate is required to be 3-16ths inch thick in order to stand the pressure of the printing press, the matrix is kept in the trough more than twice as long as before. The weight of a six-inch matrix is 24 lbs. and of its duplicate 40 lbs.; that of a one-inch new-series matrix is 8 lbs., and of its duplicate 20 lbs. Nickel-plating and steel-facing are also carried out in this department for various survey uses.
Photography was first applied to map reduction at Southampton in 1855, thus obviating the use of the pentagraph. Photozincography, or the art of printing a lino photograph in permanent ink from a zinc plate, was discovered at the same place in 1859. This process was first used for the publication of facsimiles of ancient national manuscripts; but in 1881 it was utilized for the publication of the six-inch map, and in 1889 was adopted for reproducing the larger scale maps of the Ordnance Survey. On the focussing screen of the camera a rectangle is marked of the exact size of the required copy, the plan is fixed vertically on the plan board, and the camera is adjusted so that the rectangle on the focussing screen will exactly correspond with the sheet lines of the plan on the board. The glass plate having been coated with collodion, the latter is sensitized by being immersed in a silver nitrate bath, and then placed in a dark slide, which takes the place of the focussing screen in the camera. The length of exposure varies with the amount of light and temperature. The film is developed in the iron developer, fixed in cyanide of potassium, intensified in bromide of copper and nitrate of silver, and varnished with gum dammar. The glass plates used for copying the 1-500th and 1-2,500th scale plans measure 45 inches by 30 inches, are 1/4 inch thick, and weigh 33 lbs. A negative is proved by a print on ferro-prussiate paper or by the platinotype hot-bath process. On the print the defects are detected by comparison with the manuscript plan; and they are corrected on the negatives by painting them out with lamp-black dissolved in benzole-varnish, and recutting the work in an accurate form with a finely tempered needle-point. A photo-transfer is made on Evans' thin paper coated with gelatine, sensitized by potassium bichromate. This prepared paper is exposed under the negative to the light, for two or three minutes in bright sunlight, or twenty minutes if electric light is used. The print is then laid face downwards on a zinc plate which has been covered with a thin coating of transfer ink, and is passed once or twice through the zincographic press so as to obtain a uniform coating, of ink on the print. The print is now floated on hot water, to allow the gelatine unacted upon by light to swell, after which the operator sponges the surface of the print with tepid water, and then allows it to remain in a bath of hot water for about an hour, when the whole of the gelatine not acted upon by light will be washed away, leaving the lines on the paper covered with a fine coating of transfer ink. The print is then dried, and defects made good with Abney's transfer ink; and it is then ready for transfer to zinc. The arc light is used for photographic printing in bad weather.
Zincography is a process similar to lithography, and is used in preference at the Ordnance Survey Office, owing to the portability of a zinc plate, and the small space it occupies in storage; these are advantages of great importance, because many of the plates have to be preserved, and also because small editions are printed. Until recently the whole of the work was printed in hand-presses, from each of which only about 20 copies per hour can be turned out; but a steam printing machine by Messrs. Furnival and Co. has been introduced, by which 800 per hour can be printed. Owing to the small editions printed, it was necessary to make such arrangements that a zinc plate could be fixed in the press and removed with great rapidity. For this purpose a special cast-iron bed was designed, and a zinc plate can be fixed and removed again in one minute. The edges of the zinc plate have to be bevelled to fit in this bed, and this is done by the milling machine in the electro department. It has been found that the plates are preserved in good condition for much larger numbers of impressions in this machine than in the hand-presses.
Workshops containing a small quantity of machinery are maintained, in which are made several of the articles used on the survey, such as steel surveying chains, type-palettes for holding type for stamping, steel stamps, offset staves, &c. Repairs to machinery are also effected on a considerable scale.
The different standards of length used in the surveys of the chief countries in Europe were sent to Southampton for careful comparison for the purpose of measuring an arc of longitude. The delicate apparatus by means of which they were compared is still occasionally used for the comparison of various standards.
NORTHAM IRON WORKS, SOUTHAMPTON.
These works, carried on under the name of Day, Summers and Co., belong to Messrs. Day Brothers, and cover 10 acres of ground. The firm was founded in 1834 by the late father of the present members, in conjunction with Mr. William Summers and Mr. William Baldock, under the title of Summers, Day, and Baldock; later the ,name of the firm became Summers and Day, and then C. A. Day and Co., until in 1871 the present title was adopted.
Since 1834 there have been built at these works 103 vessels, including 27 steam yachts, and machinery of over 100,000 indicated horse-power. Among the most notable ships built here may be mentioned the " Hindostan " of 3,086 tons and 600 horse-power, and the "Surat " of 3,057 tons and 600 horse-power, both for the Peninsular and Oriental Steam Navigation Co.; the former was for many years one of the fastest of their fleet, and a favourite passenger vessel. Some years ago also the " Allemannia " of 2,500 tons and 400 horse-power was built here for the Hamburg-American Co.; on her first voyage to America she beat the record, and for some time was one of the fastest steamers crossing the Atlantic. The most recent work turned out has included the tripling of the Royal Mail Steamship Co.'s " Para " of 5,000 I.H.P., which attained a speed of 16 3/4 knots; new engines and boilers of 2,500 I.H.P. for the Union Steamship Co.'s " Nubian "; also the s.s. " Tyrian " of 1,500 tons and 1,400 I.H.P., and the s.s. " Norseman" of 950 tons and 850 I.H.P., which are running for the Union Steamship Co.'s colonial and continental traffic; and new engines and boilers of 1,600 I.H.P. with forced draught for the London and South Western Railway Co.'s steamer "Diana."
One speciality made here consists of traversing sheer legs, originally introduced in 1862, of which sixty-six sets have now been made for lifting weights varying from 20 to 150 tons; among these are several sets supplied to the British, foreign, and colonial governments, notably one of 150 tons for Cronstadt for the Russian Government. Another speciality is non-fleeting hauling-up slip-machinery, in which the hauling is done by a wire rope; two examples are in use in the works on different principles.
On entering the works the block of buildings on the right contains the general offices, with drawing office overhead; on the left is the pattern shop. Adjoining the offices are the main store, the turnery, and the fitting and erecting shops, which are at present in course of alteration to meet modern requirements. Across the tram lines is the central block of buildings, containing the iron foundry, smiths' shop, boiler shop, and brass foundry. The boiler shop has recently been entirely rebuilt and fitted with all new machinery of the most modern kind, including three hydraulic riveters, of which the largest is capable of exerting a pressure of 100 tons per square inch. Outside the boiler shop come the plate furnaces and boiler smithy, behind which is the copper shop. A pair of fifty-ton sheers overhang the river and the fitting-out wharves. Behind these are two building slips and the shipyard, in which are two hauling-up slips; the larger is capable of taking up vessels of 1,500 tons, and the smaller of 500 tons. Next to the smaller slip are three blocks of yacht stores, and facing them are berths for yachts. Nearer to the entrance is the timber yard, with its saw mills, at the end of which is a large block of buildings containing spar sheds, rigging sheds, &c.; and the joiners' shops overhead are fitted with some of the most modern wood-working machinery.
NORTHAM STEAM SAW MILLS AND WHARF, SOUTHAMPTON
These works, the property of Messrs. Driver and Co., are situated on the land formerly occupied by the shipbuilding yard of Messrs. Money Wigram and Co. Considerable alterations however have been made since then. By carrying a wharf along the river front, the present proprietors, besides increasing the extent of ground, have also enabled their shipments to be landed direct from the vessels which have loaded them abroad. Steamers carrying over 1,800 tons measurement are now able to discharge at the wharf.
The machinery comprises a new sawing and planing mill, completed this year, and furnished throughout with machines of the latest type by Messrs. Thomas Robinson and Sons, of Rochdale. In addition there are other sawing and planing machines, a creosoting plant, and machinery for rendering timber fire-proof by the injection of material manufactured by the Pyrodene Fire-proofing Co. also a drying chamber for seasoning timber, with the necessary machinery. The power for working the various machines is supplied by a vertical compound condensing engine, built by Messrs. Robinson and Sons, and erected this year.
In addition to the works at Northam, the firm have also a yard with steam sawing and planing and moulding mills and joinery works, at Threefold Lane, St. Mary's, Southampton.
NORTHAM YACHT AND SHIPBUILDING YARD, SOUTHAMPTON.
This yard, belonging to Messrs. J. G. Fay and Co., and situated at Millstone Point, Northam, has been established now over twenty years, and three years ago was turned into a company, under the management of Mr. Joseph M. Soper. Of late years many of the fastest and best known English racing yachts of the larger classes have been built here, including " Irex," " Iverna," " Valkyrie," " Lethe," " Reverie," " Castanet," " Challenge," " Stranger," and " Columbine." The yard is also used for repairing and laying up yachts, having ample accommodation for hauling up; and every winter many of the racing fleet are hauled up in winter quarters. In the laying-up season the mud berths are always full with yachts of every description, from the smallest size up to the most luxurious steam-yachts afloat. There are two gridirons, on which yachts can lie ashore for scrubbing. By the aid of extensive machinery, work is carried out with the utmost despatch in every department from keel to truck.
YACHT BUILDING WORKS, BELVIDERE ROAD, SOUTHAMPTON.
These works, belonging to Messrs. Summers and Payne, were started in 1815 by the late Mr. Alfred Payne. Since that time they have built upwards of a hundred sailing yachts ranging from 2 to 120 tons, besides several steam yachts ranging from 8 to 271 tons. During the last three winters the number built has averaged fourteen, all of which have been designed by,Mr. Arthur E. Payne. The busy time in the works is in the winter and spring; by the end of May all the yachts have left the yard for the season, and in the summer there is little to be seen beyond the machinery, which consists of wood-working machines of modern construction.
SOUTHAMPTON GAS WORKS.
These works appear to have been originally established by two private individuals in 1819, when the town had a population of 14,000 to 15,000. In 1823 they were taken over by a company, which was incorporated by act of parliament in 1848. The original works have long since disappeared, as have also those which succeeded them. To meet the growing requirements they were enlarged in 1853 under the then engineer and manager, Mr. James Sharp; and in 1866-67 a general reconstruction became necessary, which was carried out under the company's consulting engineer, Mr. J. Birch Paddon, under whom acted the present manager, Mr. Samuel W. Durkin.
The present works include a wharf, with viaduct and steam cranes, for discharging coals from screw colliers on the river Itchen. The coals are distributed into three retort houses, which are jointly capable of producing about 2,000,000 cubic feet of gas per 24 hours. In the rear of the retort houses are the condensers, washer, rotary scrubber, tower scrubber, purifiers, engine room, meter and governor house, and a laboratory. There are four gasholders, of the united capacity of 1,800,000 cubic feet. On the wharf has recently been erected a sulphate of ammonia plant by Messrs R. and J. Dempster of Manchester. The town has now a population of between 60,000 and 70,000; and with villages and townships around, the works supply a large straggling district of about 80,000 inhabitants. The mains extend northwards to Eastleigh, more than five miles from the gas works, where they supply the railway station and the recently erected carriage and wagon works of the London and South Western Railway.
LONDON AND SOUTH WESTERN RAILWAY CARRIAGE AND WAGON WORKS, EASTLEIGH.
These works were opened in 1891 for the building and repairing of the carriage and wagon stock. They are situated en the eastern side of the main line from London to Southampton and Bournemouth, and cover an area of 42 acres including yard sidings, Plato 67. The floor area inside the shop walls is 456,000 square feet, and all the shops are on the ground floor. The timber is transferred over sidings on the Portsmouth line to the stacking ground and timber drying sheds, and thence is taken into the saw mill, where it is converted; it is then conveyed into the carriage building shop, where it is erected; and the carriages built are passed on over a traverser into the paint shop. The traverser, made by Messrs. Butler and Co. of Leeds, is capable of conveying a carriage of 45 feet wheelbase, which is the longest on this railway; it is driven by an engine fixed upon it. The shops have been built apart from one another, as a precaution in case of fire. The wagon building and repairing shop is at the side of the saw mill, and is connected up by a light tramway upon which timber and other stores are conveyed; it is supplied direct by the shunting engine from the sidings at the south end of the shop. The smithy and machine shops are in one block, placed between the wagon building shop and the carriage lifting shop. The steam hammers are supplied with steam from a nest of three boilers of locomotive pattern, situated at one end of the smithy; and also from two others, which are fed with the waste heat from the reverberating furnaces. These two boilers also supply the vertical engine in the machine shop. The blast for the smiths' fires and spring furnace is obtained from two of Root's blowers. The saw-mill engine is of the standard inside-cylinder locomotive type used on this railway, with cylinders 18 inches diameter and 26 inches stroke; it is supplied with steam from a nest of three boilers, one of which is fed by the sawdust and shavings from the mill. There are two lines of shafting, placed underground 116 feet apart, and driven by a 10-foot fly-wheel with ten white cotton ropes of 11 inch diameter. The paint shop, 420 feet long by 200 feet wide, is heated with steam pipes 3 inches diameter, which with the fittings complete were supplied by Messrs. Herring and Son of Chertsey; they are fed with steam from two boilers, one on each side of the shop. This warming apparatus has proved sufficient to keep the temperature in the shop up to 60° Fahr. even in the coldest days of winter. At one end of the shop, space is allotted for the trimmers. The other main buildings are 300 feet by 200 feet, 20 feet high from floor to roof plate, and 33 feet high in centre. The number of persons employed here is 1,150; and for the convenience of those living at a distance a dining hall has been erected at the entrance to the works, with ample accommodation for 600 men. The offices and stores are immediately facing the public road, and in close proximity to the entrance gates.
VOYAGE ROUND THE ISLE OF WIGHT.
The mouth of Portsmouth Harbour, Plates 43 and 51, between the Round Tower in Portsmouth and Blockhouse Fort on the Haslar or Gosport side, is only about one-eighth of a mile wide, yet has sufficient depth of water for a man-of-war to enter at any time of tide. Outside the harbour mouth a bank called the Spit runs out from its western side, extending nearly three miles to the southeast, Plate 31; whence the name Spithead is given to the roadstead or eastern arm of the sea which bounds the Isle of Wight on the north, up to the entrance into Southampton Water.
The Spithead Forts are four in number, situated on Spit Bank, Home Saud, Noman's Land, and off St. Helen's, Plate 51. The foundations of the first three are built up from the bottom of the sea; they are circular forts, constructed of granite, and faced with heavy iron armour-plates. Spit fort, the nearest to the mainland and to the mouth of Portsmouth Harbour, has easemates seawards for nine large guns, and for several smaller on the side towards the harbour. Horse and Noman's are the two largest forts, each having casemates for forty-nine guns, arranged in a lower and an upper tier. The foundations for the forts were designed in 1861 by Sir John Hawkshaw, and were carried out under his superintendence from 1861 to 1868.
About midway between Southsea Castle and Hyde, a red buoy marks the place where on 29th August 1782 the " Royal George," carrying a hundred guns, sank so rapidly that of nearly 900 persons on board almost all were drowned, including Admiral Kempenfelt. For repairing the bottom on the starboard side the ship bad been careened over too far; and the water rushed into the port holes on the lower gun deck too fast for the calamity to be averted. The wreck lay here until 1839, when it was blown up with gunpowder by Colonel Pasley.
Hyde Pier is about half a mile long. Alongside the steam railway, which starts from the pier head, runs also an electric railway constructed in 1885 by Messrs. Siemens.
The principal places round the coast of the island are seen in the following order, when starting eastwards from Hyde:-
Sea View, nearly due south of Southsea Castle. About two miles out eastwards lies the Warner Lightship, which has one mast carrying the lantern with a red ball at the mast-head; the light is white and revolving, of one minute period; a gong is sounded in thick or foggy weather. Then comes the ruined beacon-tower of old St. Helen's church; and just beyond is Brading Harbour, overlooked on the north side by St. Helen's, and from the south by Bembridge. From the estuary, which formerly extended a couple of miles inland up the eastern Yar to Brading, 700 acres of land have now been reclaimed, an unsuccessful attempt to accomplish the same object having been made 250 years ago by Sir Hugh Myddelton, who constructed the New River Water Works in London.
Off Foreland or Bembridge Point, which is the eastern extremity of the island, lies the Nab Lightship, nearly four miles out, having one mast carrying the lantern with a red ball above. It has a double-flashing light, giving two white flashes of 2A- seconds' duration every 45 seconds; a gong is sounded in thick or foggy weather. It is moored 11 mile eastwards of the Nab rock.
Whitecliff Bay is separated by Culver Cliff from Sandown Bay, where are seen Sandown, Shanklin and Shanklin Chine, Luccombe Chine, and Dimness Head, off which the training ship " Eurydice " was capsized in a squall on Sunday afternoon 24th March 1878, when returning home from the West Indies.
Beyond Dunuose lie Bonchurch and Ventnor, backed by St. Boniface Down, 764 feet. At Bonchurch was born Admiral Sir Thomas Hobson, the hero in 1702 of Vigo Bay. Beyond Ventnor a conspicuous building is Steephill Castle, erected in 1835; and next is the Royal National Hospital for Consumption, commenced in 1869 and still extending westwards.
The Undercliff extends about seven miles from Bonchurch to Black Gang. The strata overlie one another in the following descending order:—chalk marl, chalk, green sandstone, blue marl, and red ferruginous sand. The blue marl, being readily acted upon by the land springs, softens into a yielding mud, locally called " blue slipper," which slowly oozes out seawards, and leaves the sipper strata unsupported.
In Puckaster Cove stood thirty-five years ago the Royal Victoria Hotel, built on insecure ground, and wholly swept away by the sea, leaving only a trifling vestige of its foundation walls.
St. Catherine's Point Lighthouse, erected in 1838-40 on the extreme south point of the island, rises to 134 feet above sea-level, so that the light is visible 17 miles. Adjoining is the electric-light establishment, by which the lighthouse is now illuminated. A red sector of light is shown towards the Needles between the bearings of N 53r W and N 431' W from the lighthouse; this light is fixed red, varied by flashes every thirty seconds. (See pages 397-401.)
On the top of St. Catherine's Hill, the highest point in the island, 781 feet above the sea, are the ruins of a lighthouse commenced in 1785 by the Trinity House, but never completed on account of the mists whereby the light would have been so frequently obscured. Close by is the repaired octagonal tower 35 feet high of a hermitage erected towards the end of the thirteenth century, and endowed in 1323 by Walter de Godyton, for maintaining by night a signal-lamp for the guidance of mariners.
llocken End, half a mile west of the lighthouse, is distinguished seawards by a " race," which in ,bad weather becomes dangerous to vessels approaching too near.
At Black Gang Chine the old coach road ran across the chine about half way up; and traces still remain, enabling its course to be followed along the cliffs, till it turns inland west of the chino towards Chale. Walpen chine, Ladder chine, and Whale chine succeed Black Gang westwards.
From Atherfield Point runs out far into the sea Atherfield Ledge, partly uncovered at low water. On this ledge the North German Lloyd steamer " Eider " from New York stranded in a fog on Sunday night 31st January in this year, believing herself to be then in the Solent; and becoming deeply embedded on the " blue slipper" or stiff sticky slaty clay which forms the ledge, she was not got off again till Tuesday 29th March, after having been lightened of the greater part of her cargo. The Royal National Life-Boat Institution established a station here last year, and the crew of the life-boat were successful in saving a large number of lives from the stranded steamer. Irrespective of fog, St. Catherine's light is not visible from Atherfield, being intercepted by the intervening ground at Rocken End.
Brighstone or Brixton Bay and several more chines intervene between Atherfield and Brook, where at low water can be seen the few remains of a submerged copse; and pieces of fossil wood are constantly being washed up here by the sea. At Afton Down, on which are numerous barrows of the early Britons, the low red cliffs of the wealden formation are succeeded by the chalk of Freshwater cliff. Here terminates the military road, which skirts the coast from Chale; the Freshwater end has fallen into the sea at the spot marked by the two isolated masses of chalk called the Stag Rock and the Arched Rock.
Freshwater Gate, overlooked by a small fort, owes its latter name to the fact that it is the only opening down to sea-level through the range of cliffs and downs along the south coast of the island. Tho spring of fresh water, to which its first name is due, issues from the foot of Afton Down, a few hundred yards inland and below high-water level. Instead of finding its way here into the sea so close at hand, this western Far flows northwards three miles to Yarmouth, widening out into an estuary on passing after the first mils Freshwater village, where a non-return flap-sluice prevents the tide flowing up the estuary from flooding the land which has thus been reclaimed between that point and the spring at Freshwater Gate_ The High Down cliffs, rising nearly 480 feet, succeed Freshwater Gate westwards.
The Needles are three isolated rocks at the western extremity of the island. The lighthouse on the outermost was erected in 1855 by Mr. James Walker, and the light is 80 feet above high water. The light, which is a one-minute occulting, consists of a first-order lens for a fixed light, with a six-wick Trinity House Douglass mineral-oil burner in focus, showing white, red, and green sectors, to suit the requirements of navigation. A red sector, strengthened by vertical condensing prisms, is shown in the direction of St. Catherine's lighthouse between the bearings of SET S and SE from the lighthouse, in order to warn vessels approaching the A therfield ledge.
Alum Bay is distinguished by its vertical strata, sharply defined and remarkably variegated in colour: purple, red, blue, yellow, gray, and black. The alum found in the bay is no longer collected for commercial purposes; the white sand at the north end of the bay is utilized for glass-making. Headon Hill, 400 feet high, surmounted by a fort, separates Alum Bay from Totland. Bay and Colwell Bay; inland at a short distance from the latter is Golden Hill Fort on high ground.
Hurst Castle and its high and low lighthouses on the mainland, and Cliff End Fort at the north end of Colwell Bay, mark the entrance to the Solent, here only about a mile wide, across which the telegraph cable is laid. Sconce Point was formerly marked by Carey's Sconce, a blockhouse erected in Elizabeth's reign by Sir George Carey, on the site of which now stands Victoria Fort.
Yarmouth, at the mouth of the western Yar which rises at Freshwater Gate, contains the ancient mansion of Admiral Sir Robert Holmes, who was governor of the island 1667-92; the home is now the George hotel. The castle or round fort, erected in 1539 by Henry VIII, is a small semicircular battery commanding the entrance to the Yar estuary. The embankment of the marshes behind Yarmouth was carried out under Sir Robert Holmes' direction. A diminutive side-chapel of the church contains one of the finest pieces of sculpture in the island, a life-size statue in white marble of Sir Robert Holmes, beneath an arched canopy supported on solid columns of porphyry. Between Yarmouth and Lymington plies a steamboat in connection with the London and South Western Railway
Beyond Bouldnor cliff a navigable creek with many branches runs inland up to Newtown, and nearly up to Shalfleet. Along its shores are numerous saltorns, or shallow evaporating pans for obtaining salt from sea-water, which, as well as the neighbouring brickworks, no longer do so large a trade as formerly.
Egypt Point, the northern extremity of the island, facing the entrance to Southampton Water, is close to West Cowes at the mouth of the river Medina, which is navigable up to Newport, a distance of 41- miles. At West Cowes were built many of the old line-of-battle ships, including Nelson's "Vanguard," some of them carrying as many as sixty-four guns. Here are now the yacht-building yards of Messrs. White, which were originated in 1815. Since 1856 the castle has served as the house of the Royal Yacht Club, established in 1812, from which earlier year dates the popularity of West Cowes as a yachting resort. Along the shore northwards from the castle extends the Green, laid out and presented to the town by Mr. George Robert Stephenson.
East Cowes lies opposite West Cowes. On Old Castle Point, Henry VIII constructed East Cowes Castle, of which no remains are now left. Above the point is Norris Castle, built of stone so prepared as to give an idea of greater antiquity.
Osborne Palace, of which the best view is obtained from the water, was designed and built by Mr. Thomas Cubitt.
Just beyond Wootton Creek are the ruins of Quarr Abbey, now converted into farm buildings. On the opposite coast is Stokes Bay, where is the measured mile for speed trials of steamships; the eastern end of the bay is Gilkicker Point, protected by Gilkicker and Monckton Forts.
ST. CATHERINE'S LIGHTHOUSE.
Situated on the southernmost point of the Isle of Wight, near Niton, about 4i miles west of Ventnor, this lighthouse wai erected by Mr. James Walker, and the light was exhibited on 1st March 1840. The illuminating apparatus then consisted of a first-order dioptric lens for a fixed light, with a Fresnel four-wick oil-burner in focus, the focal plane being 178 feet above high-water and visible 19 miles. The approximate intensity of the light through the lens, as subsequently improved, was about 6,500 candles. Owing to the treacherous nature of the ground—consisting of upper greensand upon gault, acted upon by springs at the back which produce constant subsidences of the land—and owing also to the fact that the light was frequently capped by fog, it was deemed advisable in 1875 to reduce the height of the tower 44 feet, .and at the same time to improve the lantern and illuminating apparatus by substituting a dioptric mirror in lieu of the four metallic reflectors originally fitted for utilizing the rear light; and also a six-wick Trinity House burner in place of the former four-wick. The intensity of the light thus improved was about 8,000 candles; and the focal plane is 134 feet above high-water, with a range of 17 miles.
On 1st May 1888 the electric light was installed. For this purpose additional dwellings were erected for the accommodation of the increased staff, an engine-house was built, and other additions were made to the establishment. Electrical Apparatus.—This consists of two De Diorite'us magneto- electric machines, producing in the are a light of about 22,000 candles when working singly, with an electromotive force of about 50 volts and a current of 240 ampiaes; or about 38,000 candles when working together us they do in hazy or foggy weather, with as electromotive force of 47 volts and a current of 470 auip3res. Previous to their erection at St. Catherine's, these machines were used in 1885 at the South Foreland in the experiments on lighthouse illuminants. Each machine is composed of sixty steel permanent magnets, arranged in five rings of twelve magnets each, with twenty- four coils on each ring of the revolving armature. The coil consists of four layers of copper wire, 27 mm. or 1.06 inch deep, and about 100 mm. or 3.94 inches wide, which are connected in parallel circuit when all the brushes are in contact. The brushes are made in three sections, so that 20 or 40 or 60 per cent. or the whole current of a machine can be used in the arc. For the fine-weather intensity, 60 per cent. of the current of one machine is usually employed: that is, a current of 137 amp6res with an electromotive force of about 50 volts. The machines make 600 revolutions per minute, and are driven direct by a Robey non-condensing compound engine; they are fully described in the Trinity House report of 23rd October 1885, issued as a parliamentary paper C 4551. The power absorbed by one machine is 12.6 net I.H.P., and by the two machines 25 net I.H.P. The distance of the magneto-electric machines from the lantern is about 375 feet, the current being sent through cables laid underground in glazed earthenware pipes; the pipes have lids or covers jointed with clay, so that the cables may be readily inspected or repaired.
Illuminating Apparatus.—This consists of a second-order sixteen- sided lens, of 700 mm. or 27.56 inches focal distance, giving flashes of five seconds' duration, at periods of thirty seconds. Each lens panel consists of a central lens and portions of fifteen refracting rings, that is, fifteen segments above and fifteen segments below, embracing a vertical angle of 97°. The maximum intensity of the flashes is estimated at from 6,000,000 to 7,000,000 candles. The electric lamps are of the Serrin Berjot type, and the carbons are Sir James Douglass' fluted craterless carbons of 50 and 60 mm. diameter, or 1.97 and 2.36 inches, made with a core of graphite; the smaller, having a sectional area of 1.6 square inch, are used in clear weather; and the larger, having a sectional area of 2.26 square inches, are used for the maximum intensity or when the clearness of the atmosphere is impaired. The consumption of carbon for each size is at the rate of about 7-8ths inch length per hour.
The lens is rotated by a miniature engine driven by compressed air. The lamp table is arranged for carrying two electric lamps, which are readily changed. A three-wick portable Trinity House Douglass mineral-oil lamp is also provided, and kept in readiness for immediate use, in case of interruption to the electric light. The subsidiary red light is produced by intercepting the rear light by means of a holophote of 187.5 mm. or 7.38 inches focal distance, embracing a vertical angle of 85°; and by reflecting the light by means of inclined mirrors, it is projected over the main apparatus in the direction of the Needles, for the purpose of warning vessels standing into danger. The red sector, which subtends an angle of 10°, is fixed and is varied by flashes, the fixed light being produced by the subsidiary apparatus, and the flashes every thirty seconds by the main apparatus.
Fog Signal.—This consists of four steel air-receivers, having a collective capacity of 480 cubic feet; and a double-noted automatic siren, controlled by a Slight centrifugal governor, and sounded by compressed air at a pressure of 30 lbs. per square inch, giving high and low notes every minute. The blasts and intervals are regulated by an admission valve, which is actuated by clockwork. The siren is cylindrical, 7i inches diameter, made of gun-metal, carried on a vertical spindle, and rotating automatically at a speed of 600 revolutions per minute, within an outer fixed cylindrical casing. For the high-note siren the upper portion of the instrument has 32 ports round its circumference through both inner and outer cylinders, giving 320 vibrations per second. For the low-note siren the lower portion of the cylinders has 18 ports, giving 180 vibrations per second. The ports are cut obliquely to the radius and at opposite angles through the two cylinders, which causes the inner cylinder to revolve within the outer. The collective port-area is 20 square inches for the high note, and 18 square inches for the low. The entire instrument is enclosed in a cast-iron chest, having two separate chambers, one above the other, corresponding with the two sets of ports; into these chambers the compressed air is alternately admitted. The mouth of the trumpet is immediately above the siren, and when sounding is always turned to windward, except when the wind is directly off the shore. To render the signal instantaneous in action, three of the air-receivers are charged to a pressure of 170 lbs. per square inch; by this means the signal can be sounded and maintained by the stored air during the time occupied in getting an engine to work. The fog-signal apparatus is about 300 feet distant from the engine-house, from which the compressed air is conveyed along a 3 inch steel pipe, laid underground.
Engines.—There are three Robey semi-portable compound non- condensing engines, working at a pressure of 150 lbs. per square inch, the cylinders being 65 and 115 inches diameter by 14 inches stroke; they make about 170 revolutions per minute, equal to a piston speed of about 400 feet per minute. The boilers are of locomotive type, constructed of mild steel, and fitted with copper fire-boxes, each boiler having 56 brass tubes 11 inch external diameter by 7 ft. 8 ins. long. The grate surface in each boiler is 7 square feet; and the heating surface is 192 square feet in the tubes and 41 square feet in the fire-box, or 233 square feet total. Each engine is fitted with a Johnson's double-cylinder single-acting air-compressor, driven direct by the piston rods. The air cylinders are 81 and 11 inches diameter by 14 inches stroke, and are water- jacketed. When compressing air for storage in the air-receivers, both of the air-compressors are worked together up to 50 lbs., then the larger alone up to 80 lbs., and afterwards the smaller alone up to 170 lbs., more or less. Both cylinders of one air-compressor are used for sounding the fog signal, The power absorbed by the fog signal is 141 net indicated horse-power. The engines, with the compressors disconnected, are of 49 indicated horse-power or 36 brake horse-power; and the consumption of fuel is 3.2 lbs. of gas coke per indicated horse-power per hour.
Water Supply.—The water supply is derived from a spring, distant about half a mile from the lighthouse. It is delivered into tanks of special construction, where it is treated by Clark's softening process, and the softened water is stored in underground tanks having a total capacity of 25,000 gallons. The water before treatment has 16.7 degrees of hardness on Dr. Clark's scale, which is reduced to 4 degrees by the above process, thus keeping the boilers free from incrustation. (Each degree of hardness represents one grain of calcium carbonate per gallon.) In the event of any interruption to the constant supply, the underground storage tanks would keep one engine working for twelve hours a day for about twenty-one days. The feed water on its way to the boilers is forced through a heater, in which it is heated by the exhaust steam to temperature of 80° Fahr.
Fire Service.—A Merryweather double-acting steam fire-pump is fixed in the engine room, taking steam from either boiler, and is capable of throwing water over the lantern gallery at the rate of 300 gallons per minute. The steam cylinder is 8 inches diameter with 6 inches stroke, and the pump barrel is 6 inches diameter with the same stroke. The maximum speed of working is 260 revolutions per minute. The pump is also used for washing out the boilers. Cost.—The total cost of this installation of the electric light and the fog signal, including purchase of land, buildings, machinery, and illuminating apparatus, was £12,449. The staff consists of an engineer-in-charge, and four assistant light-keepers. The light and fog signal have worked satisfactorily and without interruption since the opening on let May 1888.
The whole of the work was carried out from the designs and under the direction of Sir James N. Douglass, F.R.S., Engineer-in-Chief to the Trinity House.
LONDON BRIGHTON AND SOUTH COAST RAILWAY LOCOMOTIVE AND CARRIAGE WORKS, BRIGHTON.
These works are situated on the triangular piece of ground bounded by the main line approaching the Brighton central station on the west side, and by the goods line and yard on the east and south, Plate 68. They have been built and enlarged at various times; and owing to their gradual increase, a portion has had to be built on the opposite side of the main line. On entering the lodge gates. which face the north end of the eastern arrival platform, the iron foundry is to the south, and next are the saw-mills for the carriage and wagon work. On the east of these are the Willa. and Robinson high-speed electric-light engines, which drive three 50-arc Brush dynamos for supplying the station and goods yard. The carriage-building shop and the boiler and erecting shops are at present undergoing extensive alterations, so ao to increase the capacity more especially of the boiler shop, with a view of putting down modern plant for the manufacture of boilers. The works are supplied throughout with a small tramway for the conveyance of material from one shop to another. There are the usual shops for repairs of locomotives and carriages, such as the machine and tool shop, wheel-turning shop, coppersmiths' and brass shop; and on the opposite side of the line are the trimming and painting shops for carriages. The supply of water for the works and running shed is pumped from deep wells on the premises; the quantity used is about one and a half million gallons per week. Locomotive, carriage, wagon, hydraulic, and general work, together with repairs to steamboats, is carried out more or less at these works.
BRIGHTON TECHNICAL SCHOOL.
The Technical School situated in York Place, Brighton, was erected in 1888 by private contributions, and was primarily intended as a day-class centre for manual instruction in connection with the public day-schools of the town, and for the development of science classes in the evening. Day and evening classes in mechanical and electrical engineering and building work have been successfully carried on. Courses of instruction in applied science, which extend over a period of three years, are provided for both day and evening students. The accommodation having become quite inadequate, it is intended shortly to erect a building in which the work can be extended to meet the increasing requirements. Tho mechanical engineering section has been supplied from private sources with the necessary appliances for the education of mechanical engineers. The machines comprise a 4i H.P. Otto gas-engine, a 2 H.P. Taugye vertical engine and boiler, an 8-inch screw-cutting lathe, a 6Wuch sliding surfacing and screw-cutting lathe, a 5-inch lathe, and two small hand-turning lathes; a planing machine by Muir, a universal milling machine by G. Lister and Co. of Keighley, a forge and necessary equipment, small bench drill, power drill, and Siemens dynamo. In the wood-working section accommodation is provided for thirty pupils. In the class room are a number of wooden sectional models of engines and machine details, including a working model one-third full size of a set of triple compound engines, supplied for the s.s. " Ivy " by Westgarth, English and Co. of Middlesbrough. This model was made in the school, and is driven by electricity; being completely in section it is a valuable aid for class instruction. Several other branches of instruction, including plumbing, carpentry, and joinery, etc., are provided for evening students. Mr. Joseph Henry Judd is the head-master of the school.