Life of Richard Trevithick by F. Trevithick: Volume 1: Chapter 15
CHAPTER XV. PROPELLING VESSELS BY STEAM.
A letter, in 1803, speaking of his high-pressure engine, with 45 lbs, of steam to the inch, says, "I was sent for to explain the engine at the Admiralty Office. They sent to inspect, and say they are about to erect several for their purposes, and that no other shall be used in the Government service." Again, in 1804, "An engine is ordered for the West India Docks, to travel itself from ship to ship." "An engineer from Woolwich was ordered down, and one from the Admiralty Office, to inspect."
With this intimate knowledge of Trevithick's schemes, and the use of his engines by the Admiralty, it is the more strange that such events are ignored, or but slightly referred to in the history of early steamboats, for in the latter part of 1804 several gentlemen had consulted him on the feasibility of destroying the French fleet by the use of high-pressure steam fire-ships.
October 5th, 1804.
Sir, Several gentlemen of late have called on me to know if these engines would not be good things to go into Boulogne to destroy the fleet, &c., in that harbour by fire-ships. They told me that a gentleman from Bath was then in London trying experiments under Government for that purpose, but whether by engine or by what plan I do not know.
A gentleman was sent to speak to me yesterday on the business, from a marquis the name I am not at liberty to give you. I put him off without any encouragement, because I would much rather trust to your opinion in bringing this business forward than any other man.
I have two 10-inch cylinders here completely ready; they are exceedingly well executed. I will not part with them until I hear further from you. If you think you could get Government to put it into execution, I would readily go with the engines and risk the enterprise. I think it is possible to make these engines drive ships into the middle of the fleet, and then for them to blow up.
However, I shall leave all this business to your judgment, but if you give me encouragement respecting the possibility of carrying it into force, I am ready to send off these two engines on speculation.
I believe if you do not bring this business forward, some other person will, and it would not please me to see another person take this scheme out of our hands.
Be silent about it at home, for I should not like my family to know that I was engaged in such an undertaking.
I would thank you for your sentiments on this business soon, as these two engines will be left unsold until I receive your answer.
There are orders for several engines since I last wrote to you.
I am, Sir,
Your very humble servant,
TRENTHAM HALL, NEAR NEWCASTLE,
October 20th, 1804.
Sir,— I received your last letter, and am really much obliged to you for your goodness in offering to give me your assistance in promoting my schemes. I am ordered by the Marquis of Stafford to leave this place for London on Monday morning to meet Lord Melville and Mr. Pitt. It is likely they may wish to be satisfied respecting the possibility of the plan I shall lay before them. I shall refer them to you for your opinion and calculations. I will write to you when I have seen these gents, stating every particular. There are many things I wish to communicate to you, for I cannot satisfy myself from my own figures. I hope you will be called on in the House in the course of next month. I expect to be in town at that time. If I am ordered to proceed with this plan for Government, there will be several things that I shall not be able to get through without your assistance. I must beg your pardon for so often troubling you for these things, for I am not master of myself, but hope you will have the pleasure of seeing these plans carried into execution.
I am, Sir,
Your very humble servant,
These traces of proposals to propel vessels by his high-pressure steam-engines, in 1804, to destroy the French fleet in Boulogne Harbour, show him as the pioneer of marine engineers. A messenger from a marquis — "a profound secret" —caused a few minutes' cautious reflection, and a wish to consult his friend, followed by, — "If you think you could get Government to put it into execution, I would readily go with the engines and risk the enterprise." He thought it possible with those engines to drive ships into the middle of the fleet, and was prepared, without a moment's delay, to place two of them in a vessel, and by them propel her to France.
Within a fortnight he was at Trentham Hall, plotting with the Marquis of Stafford, who sent him to London to see Lord Melville and Mr. Pitt. He gave more than usual thought to this compound question of propelling a vessel by steam, steering it without a helmsman, and exploding it at the required moment; for he admits, "I am not master of myself." Probably this was the only time in his life that he doubted his ability to make his high-pressure steam-engine do everything.
SOHO FOUNDRY, MANCHESTER,
January 10th, 1805.
Sir, I have answered Mr. Gundry's letter. Their engine will cost about £170, and will draw one hundred kibbals with about three bushels of coal.
I fear that engine at Dolcoath will be a bad one. I never knew anything about its being built, until you wrote to me about Penlerthy Croft engine, when you mentioned it.
I then requested Captain A. Vivian to inform me the particulars about it, and I find that it will not be a good job. I wish it never was begun. I was sent from the Marquis of Stafford to Lord Melville. I was at the Admiralty Office, and was ordered to wait a few days, before they could say to me what they wanted. I called five or six days following, but never received a satisfactory answer, only to still wait longer. But I left them without knowing what they wanted of me, for I was tired waiting, and was wanted much at Coalbrookdale at the time. When they send for me again, they shall say what they want before I will again obey the call. There was an engine, a 10-inch cylinder, put into a barge to be carried to Macclesfield, for a cotton factory, and I tried it to work on board. We had a fly-wheel on each side of the barge, and a crank-shaft across the deck. The wheels had flat boards, 2 feet 2 inches long and 14 inches deep, six on each wheel, like an undershot water-wheel. The extremity of the wheels went about 15 miles per hour. The barge was between 60 and 70 tons burthen. It went in still water about 7 miles per hour. This was done to try what effect it would have. As we had all the apparatus of old material at the Dale, it cost little or nothing to put it together.
I think it would have been driven much faster with sweeps.
The engine that was made for the London Docks, for discharging the West Indiamen, is put to work in a manufactory. They would not permit fire within the walls of he dock; there is an Act of Parliament to that effect.
There is a small engine making in Staffordshire, for the London coal-ships to carry with them for unloading.
The boiler is 2 feet 6 inches diameter and 5 feet long, with the cylinder horizontal on the outside of the boiler. The cylinder 4 inches in diameter, 18-inch stroke. I think it will be equal to six men.
The engine will always go one way. The man that stands at the hatchway will have a string to throw out a catch, which will let the barrel run back with the empty basket.
I shall go to Newcastle-on-Tyne in about four weeks, and most likely shall return to London. By that time the little engine will be sent to London for the coal-ships. A great number of my engines are now working in different parts of the kingdom. There are three foundries here making them.
They finish them in very good style; all the wrought iron is polished, and ornamented with brass facings. They are the handsomest engines I ever saw. I expect there are some of the travelling engines at work at Newcastle. As soon as I get there I will write to you.
This day I received a letter from Jane [his wife]; sad lamentations on account of my absence. I am obliged to promise to return immediately, but shall not be able to fulfil it at this moment. I should be wrong to quit this business, as there are now seventeen or eighteen foundries going on with those engines, and unless I am among them, the business will fall to the ground, and after such pains as I have taken, I am sorry to quit it, until I get it established. I am sorry to hear that your sister is about to go to London to reside, for I fear that you will now spend but a small part of your time in Cornwall, and I shall be deprived of your good advice in future.
I am, Sir,
Your very humble servant,
This account of a 60 or 70 ton barge, driven by a high-pressure steam-puffer engine, having a cylinder 10 inches in diameter, at a speed about seven miles an hour, the float-boards going at fifteen miles an hour, proves that had Lord Melville spared five minutes out of that week to keep his appointment with Trevithick, the first steam fire-ship would have dated from 1804; for within three months from that time he had driven a barge at a speed of seven miles an hour by an engine that had been constructed for another purpose, and was adapted to the steamboat on the spur of the moment by a crank-shaft across the deck, having at each end a paddle-wheel, with six paddle-boards 14 inches deep by 2 feet 2 inches long.
Trevithick's steamboat was an ordinary canal barge into which one of his steam-engines had been placed as goods for conveyance to Manchester from Coalbrookdale, as mentioned in his note of the 5th of October, 1804, and 10th January, 1805. The fact came under the notice of the Prime Minister, and the makers of the engine were among the best-known manufacturers of the day, yet no one has recorded that Trevithick constructed this first practical steamboat.
Napoleon I. is said to have exclaimed, about 1804, when reviewing his army and ships at Boulogne, "The English do not know what awaits them; if we are masters of the Channel for a few hours, England has lived her time." Napoleon certainly did not know of Trevithick’s proposed steam fire-ships, or of his courage in offering to guide them into the middle of his fleet.
Lord Dedunstanville had formed a troop of Cornish volunteers to drive Napoleon from the shores, and among them was Trevithick, who his wife said appeared well pleased with his red coat. One night a beat of drums in the Camborne streets startled the sleepers Trevithick awoke his wife, and asked what all the noise could be about. "Oh! I suppose the French must be come had you not better put on your red coat and go out? "Well, but Jane," suggested the volunteer, "you go first and just look out at the window, to see what it is!"
July 23rd, 1806.
Sir,— This day I set the engine to work on board the ‘Blazer' gun-brig.
It does its work exceedingly well. We are yet in dock, and have lifted up mud only. I hope to be down at Barking shaft in a few days, at our proposed station, when I will write to you again. I think there is no doubt of success.
A gentleman has ordered an engine for driving a ship. It is a 12.5-inch cylinder. I am at a loss how to construct the apparatus for this purpose; therefore am under the necessity of troubling you for your advice on the subject.
The plan I have is as under, unless you condemn it, or suggest a better plan. I propose to put a horizontal engine below the deck, and to put a wheel of 14 feet diameter in the hold. This wheel is to work in an iron case, air-tight; the axle to work in a stuffing box, and a pump to force air into this case to keep down the water from flooding the wheel, so that only the floats on the extremity of the wheel shall be in the water, and then only extend about 15 inches below the keel of the ship.
The cutter is about 100 tons burthen.
I wish to know the size of the floats on the wheel, and the velocity you think they should be driven.
I think the power of the engine is equal to 400,000, 1 foot high, in a minute, from which you will be able to judge what size of floats, and what velocity will be best. The air that is forced into the wrought-iron case will always keep the water down in the case to the level of the bottom of the ship. A space will be left on each side of the wheel, so that the air will never be displaced by the working of the wheel.
Your answer to this will very much oblige
Your very humble servant,
Direct to me at the Globe Tavern, Blackwall, near London."
In 1806 he had undertaken the still difficult task of placing a high-pressure puffer steam-engine of about 19-horse power in a gentleman's sailing yacht of 100 tons. Side wheels and paddle-boxes would destroy her appearance and sailing qualities. One centre paddle- wheel, enclosed in an iron case, was therefore to be fixed in the hold, the float-boards passing through an opening in the vessel's bottom. Water was prevented from rising in the case by a pressure of air forced into it by the engine, sufficient to depress it to near the level of the vessel's bottom, that the wheel might not be flooded. The paddle-shaft, where it passed through the two sides of the wheel-case, was made air-tight by stuffing-boxes. The bottom of the float-boards was 15 inches below the keel of the ship, attached to a wheel 14 feet in diameter. The engine to drive it was a 14-inch cylinder high-pressure puffer direct-action engine, of abaft 12-horse power, with cylindrical tubular boiler; the general outline of engine and boiler being very like the Newcastle locomotive of 1804.
About that time, while producing changes and improvements in marine propulsion, he became acquainted with Mr. Robert Dickinson, who bad been a West India merchant, and they became partners in the following patent:
PROPELLING VESSELS, ETC.
Trevithick and Dickinson's Specification of 1808.
In a ship or vessel properly constructed for the purpose, and to which we give the name of a nautical labourer, we place a rowing wheel shaped like an undershot water-wheel furnished with floats or pallets, but which we call our propelling boards, and of a size proportioned to the vessel; the said rowing wheel is placed vertically in a box or casing fitted to receive it in such a manner that its axis shall be at right angles to the length way of the ship or vessel, while the edge of the propelling board that is lowest shall be even with the keel of the ship or vessel, or rather with the keels, for we prefer having two, and placed at such a distance from each other as just to allow the propelling boards of the rowing wheel to pass freely between them. The foresail box or casing which contains the rowing wheel is made air-tight, and is open only at the bottom, where the floats are intended to act in propelling the vessel, and the water is prevented from rising in the said box or casing by an air-pump forcing air into it, so as to keep the water always down at the level intended. The end or ends of the axle of the rowing wheel works or work in a collar or collars of leather or any other substance fitted to prevent air from passing out and the said wheel, as also the fore-mentioned air-pump, is worked by means of a crank, a wheel, or any other suitable contrivance at one or both ends of the axle, and connected with a steam- engine, which is the power we employ to move the rowing wheel, or, in other words, to give the required movement to the vessel. In the wheel itself there is no novelty.
The novelty of this part of our invention consists in working the wheel in an air-vessel, and by means of the contained air keeping the surface of the water at such a lower level than the general surrounding surface as may prevent the water from flooding the wheel. When we mean to employ such a vessel or ship and apparatus as the above for the purpose of towing other vessels, the propelling boards of the rowing wheel and also the steam-engine must be larger in proportion to the work intended to be performed; the vessels are then fastened to each other by a towing rope or towing ropes, the headmost of them being made fast to the rowing vessel, that being the name which we have adopted for the above-described ship or vessel and apparatus. When strong tides and currents oppose the progress of the rowing vessel encumbered with those she has in tow, we facilitate the business of towing in the following manner:- To the headmost or to all of the vessels in tow we attach a pair of long poles, or what bargemen call setts, for the purpose of being dropt into the water from time to time, as is now the practice in shoal stream water, to answer the purpose of an anchor. The vessels in tow being thus secured from going along with the stream, we then propel our rowing vessel forward alone, allowing the rope that is made fast to the head- most of them to run off from a windlass placed near the stern of the rowing vessel, or in any other convenient situation. when we have run off all the rope to the end that is made fast to the windlass, we then secure the rowing vessel in her Place by dropping a liner of setts or an anchor; this being done, the vessels in tow take up their setts, the machinery of the towing vessel is then disengaged from the rowing wheel, and thrown into gear to work the foresaid windlass by the power of the steam-engine. By this means the rope is wound up on the windlass, and the vessels in tow are brought up to the rowing vessel, when the same method of proceeding is again repeated till the vessels have passed the heavy part of the stream or current, and are able to proceed without those interruptions. We need hardly add that anchors may be employed in place of setts, and that in deep water they must be used; but where the water is not too deep to admit of it, the employing of setts in place of anchors is attended with less trouble and delay. What we have stated respecting the use of our rowing vessel and apparatus in towing vessels against a stream or current applies also to the towing- ships out of any harbour. If there are floating buoys outside the harbour we row our rowing vessel to one of them, letting off from the windlass in the manner before described the towing rope made fast to the ship that is to be towed out; having reached the buoy, or dropt another if there is no buoy, we then disengage the machinery from the rowing wheel, and put it into gear with the windlass, and work the ship out of harbour by the power of the steam-engine. In many harbours this will be of immense advantage to the public, and particularly to ship-owners, for it not unfrequently happens that the wind is fair for the voyage, but foul for getting out of harbour. Here it may be proper to mention once for all, that in every case where we drop anchor, when it is to be taken up again we weigh it by throwing its windlass into gear to be worked with the steam-engine. The benefit to be derived by the public from our contrivance for towing vessels or ships would be increased if chains of proper strength moored at each end were laid in difficult currents and mouths of harbours, to be used in the following manner, that is to say, by giving the said chain one turn round the end of the windlass connected with and worked by the steam-engine the vessel could be worked in either direction of the chain without making use of the rowing wheel, merely by the revolving of the windlass. The chain should have a buoy at each end for the purpose Of being laid hold of. Nor are these all the uses to which we apply our contrivance. The apparatus or machinery which we employ to propel the vessel or vessels in the manner before described is so contrived that we can also employ it in loading or unloading not only the rowing vessel, but those she has towed, or any other that may want that assistance. Where a few articles only are to be taken on board or discharged from the rowing vessel, the common blocks and tackle may be worked by a rope attached to a windlass, and worked by the steam-engine. When more dispatch is wanted, as in discharging coals or grain from the rowing vessel or from others, and such like work where economy of time and labour is an important consideration, we facilitate the business by working a barrel in place of a windlass. This barrel, worked by the steam-engine, is kept in constant motion, while the business of discharging is constantly going on. On this barrel is placed as many endless belts as may be required for the business in hand. These belts pass respectively over a pulley of two grooves centred in a lever, the lower end of which lever is on a hinge. To the upper end of the lever, which is the longest from the centre of the pulley, a rope is attached, which goes to the vessel then discharging, where it passes through a common block in the rigging, whence the end of it descends to a man standing on the deck at the hatchway of the ship discharging. This rope is for the purpose of enabling the man, by pulling it, to lighten the endless belt by means of the longest end of the lever. From this it is plain that the pulley, will then receive motion from the revolving barrel, and continue in motion so long as the man pulls the rope tight. By this motion another rope, which we call the discharging rope, made fast to the other groove of the pulley, that is, to the one not occupied by the before-mentioned endless belt, is wound up on the said groove. The discharging rope now mentioned is the one that brings up the bucket, sack, basket, or other article from the hold of the vessel that is discharging, no more being necessary for this purpose but to carry the rope first through a block in the rigging of the vessel containing the working apparatus, and then through another in the rigging of the vessel that is discharging, and making that end fast by a hook or otherwise to the bucket, sack, basket, or other article that is to be raised; while the man who holds the other rope keeps it tight, as before mentioned, the discharging rope keeps winding up on t he fore-mentioned pulley; when the bucket, sack, basket, or other article has been raised to the height required, the man who holds the tightening rope slacks his hold, and the endless belt is thereby freed from action, so that it ceases to be carried round by the barrel before mentioned. The bucket, basket, or other article being emptied, is let go to descend again into the hold, and the endless belt being now slack, the weight of the descending bucket, basket, or other article makes the double-grooved pulley revolve the contrary way to what it did when winding on, so that the rope is un- wound from the pulley, and remains so until the man who holds the tightening rope again applies a force sufficient to make the barrel give motion again to the double-grooved pulley by means of the endless belt, as before described. Instead of the barrel and endless belt before described being used for the above purpose, other common mechanical means may be employed to throw the pulley, to which is attached the discharging rope, in and out of gear, so as to wind or unwind the discharging rope.
We have before mentioned several endless belts, though in our description we have confined ourselves to one; the other belts are for the purpose of working any required number of discharging ropes on board one or more vessels, for several vessels properly arranged may all be discharging at the same time; but all these discharging ropes being worked in the same manner by the same barrel, and by the same moving power, the description already given of one applies to any number, each having its own proper double-grooved pulley and lever.
We must here add that we do not mean, by the description which we have given of the barrel and double-grooved pulley, and the method of working them, to claim such contrivances as new inventions, or be understood as meaning to confine ourselves to the use of these means exclusively, for any of the common mechanical means that are now employed to communicate or suspend motions at pleasure to apparatus connected with any maintaining power may be used to produce the effect. The novelty of our invention is simply this: employing such a vessel as we have described, furnished with a steam-engine as a moving power, and with proper apparatus to enable us to employ the said vessel and its contents as a labourer to assist in towing of vessels in the manner before described, and in loading and unloading them, in place of using the methods hitherto in use. Where towing of vessels and discharging of vessels may not both be wanted, the apparatus may be relieved of part of its load, and of part of the expense of construction, that is to say, where only towing may be wanted the machinery need not be loaded with those parts which apply to the discharging of vessels and, on the other hand, where towing is not wanted, but only discharging and unloading, the parts that apply to towing may be dispensed with.
In witness whereof, we, the said Richard Trevithick and Robert Dickinson, have hereunto set our hands and seals, this Twelfth day of July, in the year of our Lord One thousand eight hundred and eight.
RICHARD TREVITHICK. (L.S.)
ROBT DICKINSON. (L.S.)
The nautical labourer was to tow vessels up rivers or in smooth water. If the current was too strong the vessels towed were to be moored or anchored, while it steamed ahead a convenient distance, and dropping anchor, disconnected the paddle-wheel, connected the steam-windlass, and warped the vessels at a slower speed. A permanent chain might be laid to avoid the trouble of anchoring, passing it around the windlass of the towing boat, as is now done in steam-ferries crossing rivers. The labourer, when made fast alongside a vessel to be discharged, raised the cargo by the steam-windlass.
When a few articles only are to be taken on board, or discharged from the rowing vessel, common blocks and tackle may Ii e worked by a rope attached to a windlass, set in motion by the steam-engine. When more dispatch is wanted, as in the discharging of coal or grain from the rowing vessel, or from others, and such like work, where economy of time and labour is an important consideration, we facilitate the business by working a barrel in place of a windlass. On this revolving barrel are placed as many endless belts as may be required for the business in hand. These belts pass respectively over pulleys with two grooves, centred in a lover, the lower end of which lever is on a hinge.
The movement of the lever took the slack out of the endless belt, causing the pulley to revolve; a rope from the other groove of the pulley went to the vessel's hold and raised the load until the endless belt was again loosened.
The engine used was Trevithick's high-pressure portable puffer. Several experiments were made in the Thames, with every prospect of an immediate and extensive use of the nautical labourer, when the Society of Coal Whippers protested against the encouragement of such a rival, declined to work with it and threatened to drown its inventor. Trevithick was guarded by policemen, two of them keeping watch at his house but he succeeded in proving that his idea was economical and practical, though it was impossible to stern the strong current of prejudices of the daily labourer, and the nautical labourer retired from the contest.
A curious old drawing of Trevithick's without date or name, probably belonging to the time of the patent (1808), or the fire-ship of 1804, judging from the rude simplicity of the engine and the oval tube of the boiler, similar to the first high-pressure model, shows a vessel, even including the decks, of iron, to be propelled by sails or steam. Her form was like a deep saucer, with portions of her sides cut away to make room for a paddle-wheel on each side. At the deep water-line she was 43 feet wide by 58 feet long stem and stern pieces, each 5 feet long, extended from deep water-line to the bottom of the keel, containing sliding keels of iron, each about 5 feet wide, and when down reaching 6 or 7 feet below the bottom of the vessel, acting as lee-boards and also as lever ballast when the ship was light. She was sea-going, but suitable for trading to shallow harbours, drawing 3 feet 3 inches without cargo, and 6 feet 6 inches when loaded with 150 tons. One strong mast indicates a large spread of canvas. The steam- boilers were curved to the shape of the hold, the funnel aft of the stern, the paddle-wheels 25 feet 6 inches in diameter, float-boards 3 feet 6 inches wide; two steam-cylinders 3 feet 6 inches in diameter, 8-feet stroke, with open tops and guide-wheel pistons, allowing the paddle-shaft to be kept very low, and doing away with parallel motion or guide-rods the cranks were at right angles to each other. The whole of the bottom of the vessel for 1 foot in depth was double, or cellular, a means now much used to give strength, but by him turned to further account as a surface condenser, the detail of this portion is not fully shown, judging from three other sheets of drawing in pencil, all of them unfinished, modifying and improving the whole design. The two cylindrical vessels in the plan joined to the steam-cylinder by the nozzles, were a supplementary condenser and an air-pump.
The size and shape of the boilers, and of the cylinders with the long stroke, indicate the intention to work high steam very expansively, so that at the finish of the stroke on passing to the condensers it would be of a comparatively low pressure. Immediately after this period Trevithick, on his return to Cornwall, constructed all expansive steam-engine that worked with 100 or more pounds of steam to the inch in the boiler, expanding to low pressure and condensing.
This stray waif (Plate XI.) of combined steam and sails, in an iron hull, unnamed and undated, known to Trevithick's handywork, from his well-known hand- writing in numerous explanations on the well-covered sheet of large paper, at a working, scale of 1 inch to 4 feet, so full in detail drawing, and with a reference to a written list of descriptions of the various parts, warrants the belief that the construction of such a vessel was fully contemplated, if not really carried out. a, two open-topped cylinders; b, crank-axle and paddle-shaft; c, pistons, with guide-wheels, thus avoiding parallel motion; d, paddle-wheels; e, boilers, with cylindrical exterior of cast iron, and interior wrought-iron oval fire-tube; g, iron chimney at the stem of vessel; h, surface condensers, on which he wrote "space between the ship's bottom, and the lower deck to cool the water;" i, small air-pump and condenser; j, iron tubular mast; k, sliding iron keels; l, iron gunwale; m, iron deck; n, iron middle deck; o, iron bottom deck; p, iron bottom of vessel; q, rudder; r, light water-line; s, deep water-line; t, supports and shelter for paddle-wheels. The design combines the earliest Newcomen steam-engine with that of Watt, also of Trevithick's high-pressure steam direct-action engine of the present day, extending over one hundred and fifty years of steam-engine experience. The open-topped cylinders have the simplicity of Newcomer's first engine but Newcomen dreamt not of the guide-wheel piston, and upward thrust of a rigid piston-rod moved by expansive steam, propelling a crank neither was it the vacuum engine of Watt, for it used no injection-water, the vacuum being produced by surface condensation, as in Hall's condenser. The chief power of the engine was from high-pressure expansive steam during the up-stroke of the pistons: the ideas are traceable in his letters of 1812. "The cold sides of the condenser are sufficient to work an engine a great many strokes without injection-water." "If this engine is worked with steam of 25 lbs. to the inch above the atmosphere, cutting it off at one-twentieth part of the ascending stroke of the piston, the power will be as three to two of Boulton and Watt's single engine." "The length of the piston, and the small variation that the beam will give it, is so trifling that it will not be felt." The open-topped cylinder, with a deep piston in lieu of the guide-wheel, the expansive steam, and surface condensation, are evidenced in letters of about that period.
The iron vessel in form and in detail of construction is as remarkable as the engine; its growth may be traced from the patents of 1808 and 1809 for iron ships with iron mast and yards and self-reefing sails.
The shallow draught of the vessel and its sliding keels are principles still relied on by American yachtsmen; and making the cellular bottom of the vessel a condenser is the original idea in its most simple form of modern surface-condensers.
Certainly this drawing, explained by Trevithick's letters, patents, and working engines constructed sixty years ago, combine and fully illustrate, under the most simple forms, all the leading principles of the magnificent ships of the present day, with their iron sides, iron masts, small but powerful direct-action engines, with high-pressure expansive steam and surface condensation.
Everyone thought highly of his inventions, but no one enabled him to bring them into immediate profitable use: such being the inevitable result of going too much in advance of the time. Ten years of incessant labour since his first experiments with high-pressure portable steam-engines, to bring them within the range of everyday use, had left him a lone man, bereft of liberty and broken down in health and strength.
Steel's letter of the 20th April, 1810, was addressed to Trevithick in Cornwall, where he had gone to raise money by mortgage or sale of mine shares or property, to pay the cost of showing his inventions to the public.
On his return to London, everything belonging to him was seized for debt, and he was obliged to retire to a sponging-house in a street of refuge for debtors a halfway house between freedom and imprisonment.
All this was too much for the strongest man. Typhus and gastric fever during many weeks reduced him to a state of physical helplessness, followed by the loss of intellect, and brain fever, and the patient, before so weak, required the care and strength of keepers.
In this emergency Dickinson brought his medical man to assist Dr. Walford, known to the family, disagreed with the new comer. A third medical man was called in. Anonymous letters were sent to Mrs. Trevithick on the probable result of the injurious medical treatment.
In an emergency, when it seemed a question of life or death with her husband, Mrs. Trevithick, scarce knowing what she did, sought through the streets of London for a medical man. A gentleman observing her need of help, asked what was the matter, begged her to at once return to her house, and promised to seek and send a doctor. Misfortune had reached the turning point. A kind letter from her brother advised Trevithick's return to Cornwall, and in the early part of September, 1810, being still too weak to move hand or foot, he was carried on board a small trading vessel, called the ‘Falmouth Packet,' his eldest boy, about ten years old, keeping him company.
It was war time, and the ‘Falmouth Packet' with other vessels sailed from the Downs, under convoy of a gun-brig. After three days they anchored off Dover. Trevithick went on shore and enjoyed the first short walk since the commencement of his illness, four or five months before. On getting under way again they were chased by a French ship of war. The ‘Falmouth Packet’ knew how to sail and when to hug the shore, so she showed her heels to the enemy; and in six days after leaving London landed him at Falmouth, about sixteen miles from his Cornish residence at Penponds. Taking his boy by the hand, they walked to his home, from whence two months before, when too ill to be informed of his loss, his mother had been carried to her grave front the house of his childhood.
1st June, 1810.
MY DEAR JANE,
Our hearing by every other post from Mr. Blewett, of Trevithick's rapid recovery, and also by Dr. Rosewarne last Saturday, that the fever had quite left him, gave its great satisfaction; but we are much concerned for your situation. In your letter of the 25th ult. you seemed to be much alarmed from Trevithick's weakness, but I think you cannot expect otherwise than that he will be very weak for some time, after so dreadful an attack. Do not be alarmed, I hope he will do very well you must not say anything to him about his business, that is likely to hurry his mind, until he gets better. If Mr. Dickinson receives money, he must be accountable for it. I beg that you will not hesitate asking Mr. Blewett for what you want. It gives us great happiness to hear that you enjoy health in this great trial. If you think it necessary and you wish it, I will come to you, but I sincerely hope that your next will bring a more favourable account I know Mr. Blewett will be very happy to do anything for you in his power, and I wish you would ask his advice in any business that you think is not proper for Trevithick to be told of until he gets better.
I hope you find Mr. Steel honest: in that case it is not in Mr. Dickinson's power to cheat you.
Do let me know how Trevithick's affairs stand, and what his prospects are. If he is not likely to do well where you are, do you think he would consent to return to Cornwall — if not to settle, for a little while? His native air might be a means of getting him about. Both my sisters join with me in love to you and family.
I am, dear, Jane,
Yours very sincerely,
An official document of receipt and expenditure for the five years prior to his bankruptcy shows a loss of more than £4,000 by his labours; and that he had sold or mortgaged his property and borrowed from his friends. Mrs. Trevithick, when in London, in 1808 to 1810, saw an iron steamboat of her husband's at Mr. Blewett's yard. People said that an iron boat could not float. Trevithick made a trip down the river from London Bridge in the iron steamer, and towed after him one of his iron tanks to show that they also would float.
Dickinson's letter in the early part of 1810 states that Penn had three steamboat engines then in hand; one of them with a caboose, or the nautical arm engine, and one of them a towing machine to take the place of towing machines that required repair.
On his return to Cornwall, he devoted his time to high-pressure expansive engines, and to preparing for South America; still turning over in his mind the propelling ships by steam. Mr. Newton, who rode on the first Camborne locomotive, thus writes:-
28th February, 1870.
MY DEAR SIR,
In reply to yours of the 25th, I recollect hearing Captain Trevithick, in conversation with the late Captain Andrew Vivian, above sixty years ago, say that he could construct a boat, to be propelled by the application of steam.
His idea was a boat having two keels, between which two rods might be attached, with propellers to each, similar to duck's feet, one moving forwards, whilst the other moved backwards, and so vice versa. Another idea of his was (being then war time) the application of thick, iron sides, to our men-of-war ships, to repel the shots from the enemy; these were ideas then floating in Trevithick's brain. It was at a mine meeting (North Bininer Downs). How plainly do these ideas appear as the embryo of what has taken place since; namely, the steam- and the iron-clad war ships.
I am, dear Sir,
Mr. Newton, who aspired to be a pupil of Trevithick's nearly seventy years ago on the working of the first locomotive, still lives to bear witness of the great engineer's designs for steam navigation, and the keeping out an enemy's cannon balls by iron-plated ships of war.
26th March 1812
SIR CHARLES HAWKINS, Bart.,
Sir,— Enclosed I send you a letter for Sir John Sinclair, without a seal, for your inspection, and if you approve of it please to put a wafer and forward it; if not, please to leave it rest, and send me your remarks, that I may alter it. I have not gone so fully into the business as I might have done, in expectation of Sir John Sinclair's writing to me again, with particulars, the size engine be may want, and for what purpose. If I bad money I would immediately construct an engine in a ship, at my own expense, much rather than be assisted by any person, but the misfortune I lately met with, left me without a shilling; therefore I am obliged to attend to other business for a maintenance for my family, instead of attending to purposes of twenty times the value.
I think you have heard Mr. Giddy give his opinion on the value of my new plan for driving ships, and I am really sorry to part with it so cheap to strangers but not having it in my power to carry it into execution, must submit. You see what a trifling sum will accomplish the experiment, and the value of it I believe is beyond calculation; besides the great utility to the public. I very much wish you would try the experiment, and take the advantages and he merit to yourself, instead of its going to strangers.
It might be done at Hayle Foundry, on one of their boats; the expense will not exceed £100. If you wish, you can again consult Mr. Giddy on the plan, before I engage with any other. As you have land near the mine at Gwythian, I beg to inform you that I have begun the erection of a steam-engine in Wheal Prosper mine. I was employed a few days at St. Ives, by the subscribers to the breakwater. I would be very much obliged to you to say if I must call on Mr. Hulse for payment.
Your obedient servant,
26th March, 1812.
To SIR JOHN SINCLAIR,
Sir,— I received from Sir Charles Hawkins a copy of Dr. Logan's letter to you, also a note from you to Sir Charles Hawkins, both respecting the driving boats by steam. This is a subject to which I have given a great deal of thought, as being a thing of immense magnitude and value, if it could be made to be of general utility.
So far as ideas and the outlines of theory will warrant success, I have no doubt of making it fully answer the purpose on all sorts of vessels, and in the open. sea but this cannot be done by any plan that has yet been practised.
I have been very fully informed respecting the plans and performance of the American steamboats, by practical men and others who have sailed on board them therefore I think there can be no doubt of their performance in rivers; and am surprised that English engineers have not adopted it long since without waiting to be shown the way by Americans.
The construction of steam-engines hitherto has made them very unfit for ships' purposes, on account of their immense weight, bulk, and complications.
Also the method of applying the power by wheels over the ship's sides, would make them very unwieldy in gales of wind.
The engine that I have lately invented is not one-tenth part of the weight in bulk of other engines of the same power and so simple that they are managed by any common labourer.
They are working with the cylinder perpendicular, others horizontal, and others diagonal, as circumstances require, and the fire, with all the apparatus, is enclosed within a wrought-iron boiler, so that no part could be injured from the rolling of the ship. Also the apparatus that I would use for propelling the ship should be fixed with the engine in her hold, so that no part of the machine should be exposed to injury from a heavy sea. Giving motion to a ship in the way that I propose is quite a new idea, and has never as yet been practised for any purpose whatever. When first I hit on this idea I communicated it to Mr. D. Giddy, whose theory on every occasion I have relied on, and found by practice to be correct. His opinion was with mine, that it was a thing of vast importance. I am so far convinced of its success, that if you wish to make an experiment I will lend you an engine for the purpose gratis, and also give my own time and invention therefore the loss cannot be more than on the apparatus for propelling, which I will engage shall not exceed £100, which sum will prove it on a scale sufficient for the experiment both on my plan and that now in use in America.
I have often observed horses employed to draw ships through the canal across the Isle of Dogs, from Limehouse to Blackwall, and found that three horses took two ships in tow, of three or four hundred tons burthen each, and drew them at two miles per hour.
A 30-horse engine on my plan will not exceed 8 tons in weight, 10 feet long, 6 feet high, and 6 feet wide; very little more room than six hogsheads of sugar. I think less than half this power would be sufficient for driving a ship, pumping, loading, discharging, and cooking by steam.
The steam from the salt water would be fresh for the ship's use, instead of burdening the ship on long voyages with, say six months' fresh water, weighing four times the weight of the engine and apparatus. One of the American steamboats is 160 feet long (a length equal to a 74-gun ship). The engine is called a 24-horse power the boiler is from 8 to 10 feet long; from this I judge the engine cannot be above half the power stated.
The wheels are on each side, similar to those of water-mills, and under cover; her accommodation is fifty-two berths, besides sofas.
There is one other steamboat of 85 feet long.
Respecting the engine for thrashing, chaff cutting, sawing, &c., I am now making one of about two-thirds the size of Sir Charles Hawkins's, which will be portable on wheels, and may be removed from farm to farm as easily as a one-horse cart. By placing the engine in the farmyard, and passing the rope from the fly-wheel through the barn door or window, and around the drum on the machine axle, it may be driven.
The steam may be raised, and the engine moved a distance of two miles, and the thrashing machine at work within one hour.
The weight, including engine, carriage, and wheels, will not exceed 15 cwt.; about the weight of an empty one-horse cart.
The size is 3 feet diameter, and 6 feet high. If you wish to have one of this size sent to the Board of Agriculture as a specimen, the price, delivered in London, will be sixty guineas. If you require further information, please write to me again, and I will furnish you with drawings, or models, or steam- engines of any size or for any purpose.
N.B.— I have a portable engine nearly finished which will weigh about 30 cwt. The Power is equal to 6 horses, or 21 horses every 24 hours. Price, delivered in London, £150.
I remain, Sir,
Your most obedient servant,
In March, 1812, the screw-propeller and plan for driving it were settled things in Trevithick's mind. He had seen that engines more powerful than the nautical steam-labourer of 1808, and steam-arm of 1809, were required for sea-going work, and his trials with paddle-wheels had shown that something more compact, and less in the way of wind and waves, should be devised before ocean-going steamers carrying canvas would be successful for "applying the power by wheels over the ship's sides makes them very unwieldy in gales of wind. My apparatus for propelling the ship should be fixed with the engine in her bold, so that no part should be exposed to injury from a heavy sea. Steam-engines hitherto are unfit for ships' purposes, on account of their immense weight, bulk, and complications. My newly-invented engine is not one-tenth of their weight, a 30-horse engine complete being only 8 tons." The wisdom of those words is proved by their being still applicable after fifty years of rapid advancement.
The screw-propeller was offered by Trevithick to the Navy Board in 1812, with a proposal to test its superiority to paddle-wheels by trying both of them in the same boat, worked by the same engine, the apparatus to be fixed, so that no part be exposed to injury from a heavy sea: in other words, the screw was to be placed near the stern of the vessel, and to be under the surface of the water.
Sir John Sinclair having forwarded the proposal to the Navy Board, hoped that they would order a trial of the screw, and defray the cost; and on this account Trevithick postponed his application to Mr. Praed to test it on his canal boats. After waiting two or three months, he wrote to his friend Sir Charles Hawkins:
Sir John Sinclair has taken a useless journey by calling on the Navy Board for nothing experimental will ever be tried or carried into effect, except by individuals."
Acting on these views, he proposed, at his own expense, to place a 6-horse-power high-pressure steam-puffer engine, weighing 30 cwt., an costing but £150, in a barge, that the public might see the superiority of the screw-propeller and high-pressure engine over the paddle-wheel and low-pressure vacuum engine.
April 7th, 1812.
I received your letter, enclosing one to Sir John Sinclair, which I forwarded. I wrote him that if he recommended your engines for propelling vessels, and made known your steam-engines to agriculturalists, I had no doubt but they would be universally adopted. You may write Mr. Praed offering your engines on his canal for moving barges—you may say you take the liberty to write him through me—and offer him your engines for moving barges on canals by the means of steam. Give the cost and expense of the engines and barges worked by coals instead of horses, and refer yourself to me for the advantage of a steam-engine for thrashing corn. There can be no harm in your writing Mr. Praed, who is the chief manager of the Grand Junction Canal, and certainly has it in his power to adopt your plans. I think myself pledged to carry into effect, at least to do everything that can be expected of me, to effect the small breakwater at St. Ives. It appears to me that if the small breakwater was laid down from No. 3 1/2 by the inner bamber loose to either No. 8, or about No. 9 . . . . that it would effectually secure a great number of shipping afloat. That even to No. 9 would not cost much above £20,000. . . . within the breakwater the tide would wash out the sand . . . . If the breakwater was to be laid down as placed in the map . . . .
It does not appear that Mr. Praed encouraged the screw-propeller in canal barges, though Trevithick offered to defray the cost of the experiment; and the idea remained in abeyance until 1815, when he constructed a rotary engine at Bridgenorth, hoping to make it and the screw-propeller a suitable combination for marine propulsion.
I have drawn the cylinder 9 feet in. diameter, in which the screw is to work. The screw is 8 feet 10 inches in diameter, and has two turns in 4 feet long. Of course it will gain 2 feet forward to each turn. The steam-arms revolve the same as the screw, being on the same first motion, at a rate of about 350 feet per second at the end of the arm, will give the screw about ten miles forward per hour. I have not worked the engine to any advantage since I wrote you last, because before I worked with very high steam I wished to force the boiler with cold water, which I did with 300 lbs. to the inch, which it stood exceedingly well."
This description of an upright boiler, for the rotary engine for driving the screw-propeller, was referred to in a letter a week before, and was also followed in four days by another letter, describing a tubular boiler, intended also for a steamboat:—
The boilers making for this towing engine are all tubes of 3 feet in diameter, five-eighths of an inch thick (with circular ends), of wrought iron. There are three horizontal tubes, and to each of the horizontal tubes three upright tubes are suspended.
On the 6th June, 1815, a patent was taken for various improvements:—
The fifth part consists of a mode of propelling, drawing, or causing ships, boats, and other vessels, to pass through the water, which purpose I effect by constructing a worm or screw, or a number of leaves, placed obliquely round an axis. The obliquity of the thread of the worm, screw, or leaves, admits of considerable variety, according to the degree of velocity given to it, and speed required, and according to the power with which it is driven. It may be made to revolve in the water at the head of the ship, or at the stern, or one or more worms may revolve on each side of the vessel, as may most conveniently suit the peculiar navigation on which the ship, boat, or vessel is to be employed.
In order to make the boiler of a high-pressure steam-engine of very light materials, for portable purposes, and at the same time strong for resisting the pressure, as well as for exposing a large surface to the fire, I do construct the said boiler of a number of small perpendicular tubes, each tube closed at the bottom, but all opening at the top into a common reservoir, from whence they receive their water, and into which the steam of all the tubes is united.
This tubular boiler, patented with the screw-propeller more than fifty years ago, is like a boiler now being tried in 1871 as a new thing. "The first of a series of official trials of one of the Cochrane boilers and one of the common boilers of the ‘Audacious,' 14, double-screw iron ship, was commenced on Wednesday. The Cochrane boiler has the water contained in vertical tubes, which the fire surrounds, whereas in the common boiler the water surrounds the tubes through which the fire passes.”
During twelve years he had at various times shown the practicability of steam propulsion in 1804 with a seven-miles-an-hour steamer in 1806 the single paddle steam-yacht. In 1808 the patent for universal steam on board ships. In 1812 the proposing to the Admiralty the use of the screw-propeller. In May, 1815, a screw 8 feet 10 inches in diameter had been made, and in June, 1815, a patent for the screw was applied for; and when on the verge of success, he, in 1816, sailed away to the mountains of an unknown land.
July 18th, 1815.
I really do not know what to say respecting the engines, beyond what we have frequently discussed in conversation about it. Your figures I believe are right. You have very much surprised me by stating that one of Mr. Woolf's is stopped. If the accounts of his engine at Caenver are correct, it does the most duty of either one now working in Cornwall. But what is very curious, his winding engine at Great Wheal Fortune is among the very worst of that sort. I hope that your experiment with the recoil engine for moving boats is in progress. Nothing occurs to me respecting them, except that there is not any theoretical limit to the most advantageous velocity for the propelling screw. If you are disposed to try various sizes of these screws, moving with different velocities, you must recollect that the propelling zone, with the new screw, increases as the squares of the number of revolutions in a given time; and that supposing the velocities of rotation (that is, the number of revolutions in a given time) to be the same in different screws, the propelling zone will vary as the 4th power, or as the square squared, of the diameter; or thus, suppose D the diameter and N = the number of revolutions in a minute of one screw, D the diameter, and N = the number of revolutions in a minute of the other screws. Then will their propelling power be to each other in the proportion D^4 x N^2 to d^4 x n^2. The reason why no limit can theoretically be put to the velocity most advantageous for the propelling screw is this, that the faster it goes, the less will the loss be, occasioned by the motion of the vessel through the water. The centre of propulsion (as it may be termed) is distant from the centre of the screw (supposing the radius one) one over the root of 2; that is, if a square piece, equal in size to the triangular vane (Sketch here) were to move with the same inclination and the velocity which the vane has, or 1 over the root of 2 (or about c), their effect would be equal. Suppose now, two vessels moving at the same rate through the water, each propelled by screws, one large, and moving so that the centre of propulsion has a velocity double to that of the vessel; the other smaller, but moving with a velocity ten times that of the vessel. In the first one, three parts out of four of the power will be lost in the second, only nineteen out of a hundred, not one-fifth.
I shall remain here for at least a fortnight.
I am, dear Sir,
Yours most respectfully,
Nov. 30th, 1815.
Enclosed you have a drawing for the towing engine for London, which you will execute as soon as possible. The payment you will receive from Mr. John Mills, both he and myself being equally interested in this machine; therefore, you may call for payment on either, or both, which you please.
On receipt of this drawing I wish you to inform me when you can execute it, and also whether you can understand the drawing.
I expect that the screw will be too large for the barges to take to London. If so, leave it in two parts, and we will rivet them together in London.
I wish you to send to me Herland invoice, and I will send you the balance. Let me know how you are getting on with Beeralstone engine. I hope you will forward it this next spring-tide down to Bristol, and ship it by the Plymouth trader. The adventurers are extremely uneasy on account of your delay. I was at Bristol the 22nd inst., and chartered a vessel of 90 tons burthen to take down Herland engine, which is only 11 tons, for which I am to pay £130, instead of 20s. per ton, which is the usual freight from Bristol to Cornwall.
Therefore, I have made a sacrifice of £119 entirely on account of your own neglect. Unless the Beeralstone engine is sent down this next spring (which is now nearly at hand), I shall get into further trouble and expense on that account also. Write to me by return of post to Penzance, and not to Camborne, as usual.
I remain, your humble servant,
TO HAZELD1NE, RASTRICK, and Co., Bridgenorth, Shropshire.
Drawings had been sent or a steamboat on the new plan, and the screw or screws were actually on their way to London before the patent right had been sealed.
February 28, 1816.
MR. JOHN MILLS,
Sir, On the other side you have an account of the expenses of boilers, &c.
I wish you would say what money I have received from you in the whole for Peru shares, as I do not exactly recollect, that I may enter it to your account all together.
The castings I expect you have long since received from Bridgenorth. The performance of the great engine astonishes every person here; she will do the full work of a 40-horse engine, with one bushel per hour. The boiler I have sent you will do more than a 200-horse engine.
You may get the boilers and case together in the barge immediately. Put the round end of them as near the stern of the barge as you conveniently can, because that will give more room for the machinery.
As soon as you write me that all the engine is on board the barge, I will come up to town.
The price I agreed for the freight was £10 for each tube, and 25s. per ton for the other iron, which you will find about 9 tons.
I have received news from Lima, dated 8th July last, and am informed by the Englishmen that went out, that they are getting on exceedingly well. They have been offered, and refused, at the rate of 8,000 dollars for the same share as you hold. I would thank you to write and let me know whether you have received the boilers, and how you get on. Mr. Smith is returned to Greenwich; if you call that way, he can tell you the particulars of the engine, as he saw it at work several times.
Your humble servant,
The adaptation of the screw was a great difficulty, and the addition of a newly-designed tubular boiler for driving it was a complication of difficulties that Trevithick might have found his way out of; but it was too much for Mr. Mills, or for Mr. Smith, Trevithick's London agent, and engine manufacturer, who had been to Cornwall to see what was being done by the great high-pressure steam engineer.
February 29th, 1816.
I have had some conversation with Mr. Marshall about the small engines for Manchester he says that the power of two men will be quite sufficient. They expect to have them small enough to go in at a common door, to work them in the room where the machines are fixed. I will thank you to inform me what size boiler and cylinder you consider right for such an engine; you need not trouble yourself to make a drawing. I should like to know how the thrashing machine works, soon as you have got it finished. Penn called on me a day or two ago, and said he was going to assist Mr. Mills in fitting up the towing barge, and inquired very particularly about the Herland engine.
He said Hawkins told him that your engines would do away with all the piston engines. Let me know how you are going on at Herland. I tried the engine which you sent me from Cornwall, yesterday, which works very well, except the large cock, which Field is grinding in this morning. I rather think it got damaged in the carriage. I have painted the fly-wheel, and all the parts, and it looks very well.
I have been thinking of selling it for you (which I have no doubt may be soon done), and fit up one on the new principle for working the press. I hope to receive your drawing soon for the engine for the sugar-mill. I have answered Mr. Melvill's letter to you, and Mr. Quin's also, and from what Gordon and Merpey said, expect some orders from them.
You have the enclosed in a Parcel to Mr. Page Have you any letters from Lima? Mr. Marshall says the engines are at work.
Hoping to hear from you soon as convenient, I remain, with best wishes for your health, and that of Mrs. Trevithick and family,
P.S.- I have just got a letter from Carpenter and Smith's Wharf, saying the 'Jane,' of Penzance, is arrived.
Mr. John Penn, who assisted Mr. Mills in putting together Trevithick's screw-propeller and improved steam-engine, was a millwright, and probably the founder of the present eminent marine engine-building firm, Penn and Sons.
Field, who also helped, has probably since been known as a partner in the firm of Maudslay, Son, and Field, equally eminent with Penn and Sons. Harry Maudslay, also one of the firm, was then known as a clever smith employed by Trevithick.
James Nasmyth, then a boy, working for Maudslay, has since been the maker and patentee of Nasmyth's upright or chimney boiler, for which the writer, who had the pleasure of his personal acquaintance, paid him patent light, though it was almost an exact copy of Trevithick's boiler made and used in 1815, and formed part of the engine that Field, and Penn, and others, probably Maudslay and Nasmyth, saw and worked on.
In 1833, the writer, seeking his fortune in London, and knowing that Maudslay, then a leading marine-engine builder, had benefited by Trevithick's patent tanks, and steamboat discoveries, and hoping a return for benefits received, sent in his name as the son of Trevithick, the engineer, and ask permission to go through the works. The answer was, "We are very sorry, but it is against our rule;" but he gained admittance by one of the leading mechanics, his relative, schoolfellow, and early shop companion, now the leading mechanic in Penn's factory, and the grandson or grandnephew of old Sam Hambly, who, as Trevithick's helper, had worked side by side with Penn and Maudslay in putting together the tanks, nautical labourer, and screw-propeller, during 1808 to 1815.
July 26th , 1816.
I have just seen Mr. Mills. He wishes me to inform you that there will be a great many engines wanted in Holland for the boats. He has seen the small engine which I have nearly finished, and wishes to try it on the water with your screw. I shall, therefore, be obliged to you to say by return of post what you think should be the diameter of the screw for this size engine, and in what way it would be best to work it perhaps with a universal joint, if the engine will go fast enough this way; but let me have your opinion on this particular. I expect to have it finished in a week, when Mr. Mills will be ready with a proper boat for the purpose. He seems to have some doubts of the screw, but says that if this should not answer, the old way with the wheels will do very well. I have not seen any of the sugar people, but told Mr. Penn to make out his bill for them. Mr. Strattan, Gutter Lane, called on me the other day, and I promised him a sight of the engine at work very soon. Don't make any arrangement with him about engines till you hear from me again. Mr. Penn told me something about him which I will explain in my next. We had a letter from Mr. Page this day; shall write him in a day or two. I have not time for more now, as it is four o'clock. You shall hear from me again the beginning of the week, but expect to hear from you by next post.
P.S. I will give you the size of the oven in next.
Mills liked the look of Trevithick's new engine in Smith's shop, and wishing to have a screw-steamer, offered his boat that the engine might be placed in it, Smith engaging to discover from the great necromancer, then in Cornwall, how the screw should be made, how it should be fixed, and how it should be worked, to which an answer was sent by return of post. Mr. Smith had married a sister of Mr. Page, who, with his partner Day, were solicitors for the South American mining scheme.
August 1st, 1816.
I have just received your letter dated July 29, and shall proceed with the screw, according to your direction, but am much afraid that I shall not have the engine finished before you come. I wish you would stop another week, that I may get it done before you see it.
Mr. Mills says that engines of 30 and 40 horse-power will be wanted, and a great many of them, and is very anxious to see the small one tried.
I am very forward with it now; but, being a new thing to me, have had many tools to make, and Mr. Penn has been rather unfortunate in the casting the flywheel, which you saw on his premises was broke in the turning, and the first cylinder was good for nothing, and we had to cast another, which is pretty good. Horton charges £46 for the boiler, which appears to be well made. I have got it on the wheels, and have finished the box at the bottom for the chimney, and have ordered the pipe for the chimney in town. The stuffing box for the valves is screwed on the top of the boiler, and the double cylinder is screwed to the side. The standards for the shaft of the fly-wheel are also fixed, and Penn is turning the shaft from a wood pattern, which I have given him. I am going to town this afternoon about the copper tubes or pipes for steam and discharging. The fire-door is finished, and the bars are in place. All this is done, and yet I think it will take another week to complete it, and I very much wish to finish it before you see it.
The sugar-bakers have not got Mr. Penn's bill yet, but this I suppose does not much signify.
I have asked the plumber to give his charge for what little he did in this business, but have not got it yet. We received the fish, hams, &c., yesterday evening, which are not in the least injured. We are much obliged to you for them. I shall not trouble you about the oven yet, as I cannot ascertain the size exactly, and am too much engaged at present to think about it. We are very glad that you are all well, and shall be happy to see you at Greenwich, and perhaps Mrs. Trevithick or Miss Trevithick will take a trip with you. I need not add that we shall be happy to see them.
I am, dear Sir,
Trevithick's leaving for Lima in two months from the date of those experiments prevented his perfecting the screw-propeller.
A Select Committee of the House of Commons commenced its sittings May 8th, 1817, to inquire into the use and safety of Trevithick's high-pressure marine engines.
Mr. Bryan Donkin examined:— Witness went down to Norwich as a volunteer, to inquire into the cause of the explosion of a steamboat was accompanied by Mr. Timothy Bramah and Mr. Collinge. Was of opinion that the immediate cause of the explosion had been the use of steam of a very high expansive force. The approximate cause was a deficiency in the strength in the end of the boiler. It was cylindrical. One end was wrought iron, the other end cast iron. It appeared to have been previously of wrought iron, and had been cut out, and cast iron substituted in its place. Would not choose to use a high-pressure engine, from the danger which arose from their use. Scarcely ever saw the low-pressure engine beyond 6 lbs. to the inch. Thought it just to state to the Committee that there was an advantage to be derived from the use of high-pressure engines on board of boats. Had likewise been told, though without having seen one, that Trevithick had invented a method of making boilers by increasing the length, and decreasing their diameter, so as to render them capable of maintaining pressure to a much greater degree than heretofore. Had no doubt but Cornwall had derived incalculable advantages from the use of high-pressure engines.
Report of the Select Committee of the House.— Your Committee find it to be the universal opinion of all persons conversant in such subjects, that steam-engines of some construction may be applied with perfect security, even to passenger vessels; and they generally agree, though with some exceptions, that those called high-pressure engines may be safely used, with the precaution of well-constructed boilers and properly-adapted safety-valves and further, a great majority of opinions lean to boilers of wrought iron or metal in preference to cast iron.
At the time of the inquiry by the House of Commons into the propriety of allowing the use of the high-pressure steam-engine in England, Trevithick was successfully working it on the top of the Cordilleras. The new boiler referred to by Mr. Donkin was the multitubular boiler, constructed for the screw-propeller engines.
On Trevithick's return from America, ten or twelve years afterwards, he wrote:—
The boilers in use prior to your petitioner's invention could never, with any degree of safety or convenience, be used for steam navigation, because they required brick and mason work around them to confine the fire.
This statement, made fifteen or twenty years after his numerous applications of steam on board vessels, beginning in 1803 with the dredger-boat in the Thames, and then the steam-barge in 1804, prior to which no boiler, except his own, had been erected without a casing of brickwork flues, proves him to have been the first practical applier of the marine steam boiler and engine.
In 1788 Patrick Miller, Taylor, and William Symington, tried to propel a boat by a 1-horse-power steam-engine, and after thirteen years of consideration, Symington, hoping he had made the idea practical, took a patent in 1801 for "the application of such an engine, to propel a vessel by paddles;" and in 1803 the ‘Charlotte Dundas' was propelled by steam in the Firth of Clyde, but after a short time was laid aside. "In 1807, Fulton, of New York, launched the 'Claremont,' said to be the first steamboat that successfully carried passengers for hire. In 1812 the 'Comet' steamboat, by H. Bell, plied between Glasgow and Helmsburgh, and in 1813 the 'Elizabeth' steamboat, on the Clyde, was probably the first remunerating steam-vessel in the world" so that twenty-four years elapsed between the idea, of Miller and Symington, and its first practical use.
The first attempt, on any scale worthy of notice, at navigation by steam in Britain was made about this period on the river Clyde. A boat of about 40 feet keel and 101 feet beam, having a steam-engine of 3-horse power, began to ply on the Clyde as a passage-boat between the city of Glasgow and Greenock in 1812 but owing to the novelty and apparent danger of the conveyance, the number of passengers was so very small that the projectors for some time hardly cleared their expenses.
It is curious that while this experiment was going on in Scotland, Trevithick was corresponding with Sir John Sinclair on the subject, and on the 26th March, 1812, stated: "I have found that three horses towed two ships, of 300 or 400 tons burthen, at two miles an hour," thus intimating the probable power of their 3-horse 'Comet'; and added, "a 30-horse steamboat-engine on my plan will not exceed 8 tons in weight." But Trevithick was far in advance of such small work; he had then the screw-propeller in hand. "The construction of steam-engines hitherto has made them very unfit for ship purposes, on account of their immense weight, bulk, and complications also the method of applying the power by wheels over the ship's sides would make them very unwieldy in gales of wind; the engine that I have lately invented is not one-tenth part of the weight or bulk of other engines of the same power the fire, with all the apparatus, is enclosed within a wrought-iron boiler, so that no part could be injured from the rolling of the ship." This boiler, patented by Trevithick in 1802, and used in his steamboat of 1804, was precisely the one which enabled this Clyde boat of 1812 to work, and is thus described:
The boiler in which the steam is produced is made of strong wrought-iron plates, and the fire- place is an iron tube contained withinside; the smoke, after passing through two or three turns of the tube in the boiler, passes off through the chimney, which is an iron tube. The boat was about 80 tons burthen; she went about six miles per hour in smooth water the circumference of the paddle-wheels went at a speed of thirteen miles per hour.
Not only was the Clyde boat of 1812 a close copy of Trevithick's boat of 1804 in size of boat, speed of wheels and of boat, and kind of boiler, but the words used by Rees in its description read almost as extracts from Trevithick's letters of 10th January, 1805, and 26th March, 1812, thus making good his statement that "the boilers in use prior to your petitioner's invention could never, with any degree of safety or convenience, be used for steam navigation, because they required a protection of brick and mason work around them."
According to Rees, the American first steamboat experiments had the same origin, from Trevithick through Symington, though he says that the high-pressure engines ought not to be allowed in steamboats, and fails to mention the name of Trevithick.
The Scotchmen feared to go by the Clyde boat of 1812, because it was worked by Trevithick's high-pressure boiler and if, as has been said, articles in Rees' Cyclopedia' were written by Dr. Robison, we can understand why, as the supporter of Watt, he did not trouble to trace the particulars of Trevithick's steam- barge of 1804, which worked with steam of from 50 to 100 lbs. on the inch, being just the pressure now much approved of in steamboats.
The ‘Egypt,' which is, we believe, except the ‘Great Eastern,' the largest steamship afloat, is fitted with engines constructed on the compound principle, with boilers giving steam of 75 lbs, to the square inch. The ship has five steam-winches, and a steam capstan and windlass of Napier's patent. The steam-winches supersede a vast amount of manual labour; they work the pumps, hoist the sails, and discharge and load the cargo. The 'Egypt' has four masts all the lower masts are of iron, while the lower yards and lower top-sail yards are made of steel.
The principles illustrated in this modern iron steam and sail ship, built one hundred years after the birth of Trevithick, may be traced in his own description of his inventions sixty years ago. It is not meant to compare the 'Egypt' of to-day with the iron ship of 1809, or the Thames experiments and screw-propeller and multitubular boiler of 1816; but it may be said of each of them that they were iron sailing ships, with iron masts and yards, propelled by a screw, driven by direct-action expansive engines, with surface condensers, and tubular boilers giving steam of about 75 lbs, on the square inch, and that in each of them the cargo, the sails, and the anchor were to be lifted by the steam-engine. The acts of Trevithick in the steam-dredger engine of 1803, the steamboat of 1804, the cargo and anchor lifting engine of 1808, the iron steamship with iron masts, direct-action expansive steam-engines, and surface condensers of 1809, and the screw-propeller and multitubular boiler of 1812 to 1816, added to the modern improved detail of construction, constitute the iron steam fleets of the present day.
- See Trevithick's letter, May 2nd, 1803, chap. ix.
- See letter, Feb. 22nd, 1804, chap. ix.
- See Trevithick's letter, January 10, 1803, chap. XV.
- See Wheal Prosper Engine and Herland Engine, chap. xix.
- Trevithick's letter, December 7, 1812, chap. xvii.
- Patent of 1809, and description or iron ship, chap. xiv.
- See chap. xii
- See Dickinson's letter, chap. xiii.
- See letter to Sir Charles Hawkins, 13th June, 1812, chap. xvi.
- Trevithick (in his copy of this letter) probably could not decipher the writing of Sir Charles Hawkins, marked by omissions, and toward the end of the letter gave it up as impossible.
- Trevithick's letter, June 13, 1812, chap. xviii.
- See letter. 12th May, 1815, chap. xvi.
- See letter, 7th May, 1815, chap. xvi.
- See letter, 16th May, 1815, chap. xvi.
- See patent, 6th June,. 1815, chap. xvi.
- See Trevithick's letter, 7th May, 1815, chap. xvi.
- Abstract of evidence before a Select Committee of the House of Commons on Steam.
- Distinguished Men of Science,' by H. Walker.
- Woodcroft 'On Marine Propulsion.’
- History of the Steam-Engine, by Stuart.
- See Trevithick's letter, 26th March, 1812
- See Bees' Cyclopedia,"Steam-Engine," published 1819.
- See Petition to Parliament, chap. xxv.
- The Illustrated London News,' November 18, 1871.