Life of Richard Trevithick by F. Trevithick: Volume 2: Chapter 27
CHAPTER XXVII. HEATING APPARATUS - MARINE STEAM-ENGINES - REFORM COLUMN.
LAUDERDALE HOUSE, HIGHGATE,
March 1st, 1830.
MR. GILBERT, Sir,— I have to apologize for my neglect in not calling on you, but ill-health prevented it. I left home on the 11th February, arrived in town on the 14th, and remained there until the 24th, when I was compelled to leave for this place, having a free good air. I am now taking, twice a day, the flowers of zinc, from which I hope to be soon right again. I am much better, but afraid to enter the city. I hope to be able to call on you before the end of this week, being very anxious to see you, having a great deal to communicate respecting the experiments I have been making, which will bear out to the full our expectations.
Your hot-house apparatus has been finished nearly three months, all but two or three days' work to fit the parts together; I expect that before this they are in Penzance, waiting a ship for London. While making a sketch of your work for the founder, a thought struck me that rooms might be better heated by hot water than by either steam or fire, and I send to you my thoughts on it with a sketch for your consideration. I find that steam-pipes applied to heat cotton factories, with 1 surface foot of steam-pipe, heat 200 cubic feet of space to 60 degrees. I also found in Germany, where all the rooms are heated by cast-iron pipes about the heat of steam, that 1 foot of external flue heated 160 cubic feet of space to 70 degrees.
I find also that about 200 surface feet of steam-engine cylinder-case will condense about as much steam as will produce 15 gallons of water per hour, and will consume about 4 bushels in twenty-four hours to keep the temperature of 212 degrees. One bushel of coal will raise the temperature of 3,600 lbs. of water from 40 to 212 degrees.
A boiler, as the drawing, will contain 1,200 lbs. of water, and consume one-third of a bushel of coal to raise the water from 40 to 212 degrees. It has 40 surface feet of hot sides giving out its heat. The 12-inch fire-tube in the boiler would raise the temperature to 212 degrees in about forty minutes. By these proofs it appears that 50 feet of surface steam sides will require 1 bushel of coal every twenty-four hours to keep up the boiling beat; therefore this boiler, having 40 surface feet, would give out the heat from one-third of a bushel of coal in twelve hours.
Now suppose this charge of heat required to be thrown off in either more or less than twelve hours, the circular curtain would adjust the heat and time for extracting it.
By the foregoing this coal and surface sides would heat to 60 degrees for twelve hours a space of 6,800 cubic feet, equal to a room of 25 feet square and 11 feet high. If this boiler was placed in a room with a chimney, its water could be heated by having a small shifting wrought-iron chimney-tube of 4 inches diameter and 2 or 3 feet long attached to the end of the boiler while it was getting up steam, after which it might be removed, and the doors at both ends of the boiler closed; and as the boiler contains and retains its heat for twelve hours, more or less, it might be run on its wheels to any fire-place or chimney to get charged with heat, and then run into any room, where there was no chimney, or into bed-rooms, offices, or public buildings; it would be free from risk, not having either steam or loose fire. The circular curtain, being fast to a wood table, would by being drawn up or down adjust the required heat and hide the boiler, and would be warm and comfortable to sit at. I think this plan would save three-quarters of the coal at present consumed; the expense of the boiler will not exceed £5. When you have taken it into consideration, please to write me your opinion.
I remain, Sir,
Your very humble servant,
P.S.— Boiler, 3 feet diameter, 3 feet long; fire-tube, 19 inches diameter, placed in the boiler, the same as my old boiler made of iron plates 1/8th of an inch thick, weighing about 2 cwt.
I had a summons to attend at Guildhall last Saturday on the coal trade, and was requested to attend a committee at Westminster for the same purpose, in consequence of my applying small engines to discharge ships.
I attended, but with difficulty, from my ill-health.
Trevithick was not above scheming for his friend's hot-house, warming it by a boiler on wheels, in form like his high-pressure steam-boiler. Rooms had before been heated by steam or hot air in pipes; but he thought a more simple and economical plan was to heat a certain quantity of water to boiling heat at any convenient place having a chimney, or in the open air, and then wheel the apparatus into the room to be warmed. If the room had a chimney, the fire could he kept up, or the temporary iron connecting chimney be removed and the apparatus wheeled into the middle of the room and used as a table.
The scheme promised to be successful, for in a letter nine months after the former he wrote that he had taken a patent for France, where it had made a great bustle among the scientific class, for coal in Paris was 3s. a hundredweight; some hot-water room-heaters were the following day to be forwarded from London to Paris; while the numerous orders were more than he could execute. One in use at the 'George and Vulture' Tavern, of a Gothic shape, handsomely ornamented with brass, about two-thirds the size of the one in Mr. Gilbert's hot-house, burns 7 lbs. of coal a day, keeping the room at 65 degrees of heat during fifteen hours. The rage amongst the ladies was to have them handsomely ornamented.
Believing that they would be remunerative, he applied for the following English patent in February, 1831.
Apparatus for Heating Apartments. 21st February, 1831.
NOW KNOW YE, that in compliance with the said proviso, I, the said Richard Trevithick, do hereby declare that the nature of my said invention of a method or apparatus for heating apartments, and the manner in which the same is to be carried into effect, is shown by the following drawings and description, where Fig. 1, Plate XVI., represents a longitudinal vertical section through the middle of a metallic vessel capable of containing a considerable quantity of water, with a fire-place in the inside, surrounded with water in all parts except at the doorway and at an opening where the smoke may pass off into a common chimney. Fig. 2, a vertical section near the fire-door, at right angles to the section shown at Fig. 1; with the sections are also shown wheels and handles, which lie out of the planes of the sections. The letters of reference indicate the same parts in both figures. a, the vessel; b, the space for containing the water; c, the fireplace; d, the fire-bars, or grating; e, the ash-pit; f, an inner door, to prevent the air from entering over the fire, yet allow it to pass into the ash-pit, and thence up to the fire through the grating; g, an outer door, to be shut when the fire is to be extinguished; h, a chimney or flue, to convey the smoke into a common chimney: this flue may be removed when the water boils, and then the opening of the flue may be shut, to keep in the heat, either by a door or by a plug fitting the opening; k, the cover of the vessel, having a rim all round, within which iron cement is to be driven to make the vessel steam-tight; l, a hole in the middle of the cover, into which a plug is dropped having a fluted stem and a flat head ground steam-tight upon the cover; this plug or valve is for the purpose of allowing the escape of steam if it should be raised above boiling point, and the valve is taken out when it may be necessary to pour water into the vessel; m, four wheels, on which the vessel may be easily removed from one room to another; n, two handles, to facilitate the removal. To use this apparatus for the warming of an apartment, the vessel is nearly filled with water, and placed so near to a chimney in another room, if more convenient, that the flue-piece h may convey away the smoke; a fire is then lighted upon the grating d, and continued till the water boils, when the flue-piece is taken away, and the flue opening stopped with the plug or door, and also the outer fire-door closed. In this state the apparatus is drawn into the apartment to be warmed, where it will continue for many hours to give of a most agreeable heat without any of that offensive odour usually experienced from stoves heated by an enclosed fire. Figs. 3, 4, 5, and 6 represent another form of my apparatus for heating churches or other large buildings. Fig. 3, a vertical section, from A to B, of Figs. 5 and 6, with a representation of the flue and its flanch, which lie beyond that section and the fire door-way and its flanch, which lie nearer, and also the four wheels, two of which are on each side of the section. Fig. 5, a horizontal section, from E to F, of Figs. 3 and 4. Fig. 6, a horizontal section, from G to H, of Figs. 3 and 4, with a view of the four handles situated at another level than the section, and of the fire-bars at a lower level; the same letters of reference signify the same parts in all the four figures. a, the outer case of the water-vessel; b, the cover; c, the space for water; d, the fire-place and flue; e, the fire-bars, made in two pieces, to be introduced through the fire doorway; f, the ash-pit; g, the fire-door; h, pipes open at top and bottom, cemented into holes in the bottom, and in the cover oft he water-vessel; these pipes are to admit a current of air up through them, in order the more speedily to carry the beat into the building; k, the aperture in the cover, to supply the vessel with water, and the plug to keep in the steam; l, four wheels, on which the whole is moved, each wheel revolving in a recess cast in the bottom of the outer case, as represented by dotted lines in Figs. 3 and 4; m, four handles; n, the flanches of the fire doorway and of the flue, represented in Fig. 4 by dotted lines. A pipe to communicate with a chimney while the water is being heated must be made to suit locality, and therefore cannot require any description. This apparatus can be heated in a vestry room, and the fire-door and flue closed and then wheeled into the church, where it will soon diffuse a most comfortable warmth; or the heat may be kept up while standing in its place by having a constant communication with a chimney, and thus diffuse a much more salubrious heat than can be obtained by metallic or earthen stoves heated immediately by the fire.
It is doubtful if the profits he received from the heating apparatus covered the cost of the patent. The first stove was not unlike his first locomotive boiler. The more highly-finished stove resembled the marine tubular boiler, also of former years, in the further application of which we now follow him.
January 24th, 1829.
Sir,— Since I have been down I have made a small portable engine, and set it to work on board a coal-ship for discharging the cargo; it is very manageable, and discharges 100 tons with 1 bushel of coal, without any person to attend it, there being a string that the man in the hold draws when the coal-basket is hooked, which is again drawn by the man who lands the basket on the deck; the string turns and re-turns the engine. It is near a ton weight, but as I find it double the power required, I am now making a smaller one, 3.5 feet high and 3 feet diameter, about 12 cwt.
I intend this engine to warp the ship, pump it, cook the victuals, take in and out the cargo, and do all the hard work. The captains are very anxious to get them on board every ship. I think that an engine of 39 cwt. would propel their ships four miles an hour over and above the other work of the ship, and would neither be so heavy or take so much room as their present cooking house and furnace. I think that two iron paddles, one on each side of the rudder, under the stern, would do this very well; they would be in dead water, and out of the swell of the sea, and by being deep in the water would have a good resistance. Two paddles, each about 4 feet deep and 3 feet wide, would do this, without their rising out of the water; therefore their stroke would be nearly horizontal. The return stroke would be in the water. Thus, let the paddle stand perpendicular in the water, two-fifths of its width on one side, and three-fifths on the other side, the centre, which would turn its edge to the water on its back stroke, and its flat to the water on the forward stroke it would be light, and out of the way of anything. I have a patent now going through the office for all this, which will also cover the new principle of returning the heat back again, as already described to you. The engine for drawing in Holland will be ready about the end of February, and by that time I shall have a complete portable engine ready for London for discharging, when I shall be in town.
I remain, Sir,
Your very humble servant,
P.S.— Wheal Towan engine is working with three boilers, all of the same size, and the strong steam from the boilers to the cylinder-case the boilers are so low as to admit the condensed water to run back from the case again into the boiler. They find that this water is sufficient to feed one of these boilers without any other feed-water therefore one-third of the steam generated must be condensed by the cold sides of the cylinder-case, and this agrees with the experiments I sent to you from Binner Downs. Wheal Towan engine has an 80-inch cylinder, and requires 72 bushels of coal in twenty-four hours; therefore the cylinder-case must in condensing high-pressure steam use 24 bushels of coal in twenty-four hours. Boulton and Watt's case for a 63-inch cylinder, working with low-pressure steam, condensed only bushels of coal in equal time, the proportions of surface being as 190 to 240 in Wheal Towan. Nearly five times the quantity was condensed of high steam than of low steam, proving that there is a theory yet unaccounted for.
Trevithick's portable high-pressure steam-puffer engine, when it discharged the first cargo of coal from a vessel at Hayle, was worked by the writer it stood on the wharf near the ship, and on a signal from the hold, steam was turned on raising rapidly the basket of coal the required height. In trying how quickly the work could be done the hook missed the basket-rope, and caught the man under the chin, swinging him high in the air, much to the engine-man's discomfiture. Fortunately the suspended man had the good sense to lay hold of the rope above his bead, and so supporting his weight, no great harm was done.
The object and the means were the revival of the nautical labourer of twenty years before.  The boiler was a wrought-iron barrel on its end, on small wheels, with internal fire-tube, in shape like the boiler of the recoil engine of 1815;  but less high in proportion to its diameter. The cylinder was let down into the top of the boiler, and like Newcomen's atmospheric engine had no cylinder cover. The piston-rod was a rack giving motion to a small pinion fixed on a shaft on the top of the boiler, and to a large grooved wheel, around which was wound the whip-rope from the vessel's hold; a brake-lever enabled the engine-man either to stop or to reduce the speed. Four months prior to the date of this letter he had sent a written offer to the Common Council of the city of London, offering to provide engines to discharge all coal-ships for the saving he would effect in six months, or he would supply an engine and boxes complete for 100 guineas. He at the same time suggested that in place of the baskets holding 1 bushel, iron boxes on wheels, holding 4 bushels, with a spring steelyard attached, should be used with his steam-engine, giving the exact weight without delay. He seems to have forgotten his nautical labourer patented twenty years before;  but yet reproduced something very similar.
Every trading vessel was recommended to carry at least a 12-cwt. high-pressure steam-puffer engine, suitable for warping, pumping, and discharging cargo; but a 30-cwt. engine, not occupying more room than a caboose, would in addition cook for the crew, and propel the vessel at three or four miles an hour. Two iron paddles, like the duck's feet described to his Binner Downs friends many years before,  were to be fixed on an iron shaft across the stern of the vessel, receiving from the engine a motion like a pendulum. Each duck's foot was an iron plate feet deep and 3 feet wide, turning partly round on its iron leg, to which it was attached as a vane, about 1 foot of its width on one side of its leg, and 2 feet on the other side; when the leg and foot were drawn toward the vessel, the foot, turning on its leg as a centre, exposed its edge only to the water; on the reverse movement, the longer side like a vane turned round until its flat was opposed to the water, in which position it was kept by a catch until the return movement, so that when it propelled, its whole surface pressed against the water, and when moving in a contrary sense, only its edge offered resistance to the water.
The writer has no record of the practical application of the duck's foot as a steamboat propeller; but the portable puffer-engine now pulls on board the fisherman's heavy nets, and the magnificent steamer 'Adriatic' hoists her sails on iron yards and masts by six of those steam helps. 
Twenty years before he had solicited the Navy Board to try his iron ships propelled by high-pressure steam-engines, and had shown their applicability as steam-dredgers; and again, shortly after his return from America, he pressed on their attention the same subject under new forms, followed by communications with their engineer, Mr. Rennie, and a proposal to place an engine in a boat at his own cost.
The writer has attempted in this and the preceding chapter to classify Trevithick's schemes, crowded together in those last years of his life, but the subjects so run into one another that the acts of twenty years before must be borne in mind to enable the more modern plans to be understood. The letter introducing the surface condenser, in 1828, at the commencement of the former chapter, was in a month followed by that recommending a particular kind of paddle to be used as auxiliary steam-power, and after six months of experiments, by the patent of 1831, and the following correspondence:—
LAUDERDALE HOUSE, HIGHGATE,
June 10th, 1830.
Sir,— Yesterday I saw Mr. George Rennie, and he requested me to write to the Admiralty, a copy of which I send both to you and to him, for your inspection. Mr. Rennie said there was a great deal contained in what I had stated to him, and that he would with pleasure forward my views, as far as he could with consistency.
I remain, Sir,
Your very humble servant,
TO THE RIGHT HONOURABLE THE LORDS COMMISSIONERS OF THE ADMIRALTY, &C., &e., &e.
About one year since I had the honour of attending your honourable Board, with proposed plans for the improve. meat of steam navigation; find as you expressed a wish to see it accomplished, I immediately made an engine of considerable power, for the express purpose of proving by practice what I then advanced in theory. The result has fully answered my expectations; therefore I now make the following propositions to your honourable Board, that this entirely new principle and new mode may be fully demonstrated, on a sufficient scale for the use of the public.
I humbly request that your Lordships will grant me the loan of a vessel of about two or three hundred tons burthen, in which I will fix, at my own expense and risk, an engine of suitable power to propel the same at the speed required. No alteration in the vessel will be necessary, and the whole apparatus required to receive its propelling force from the water can be removed and again replaced with the same facility as the sails, thus leaving the ship without any apparatus beyond its sides when propelled by wind alone, and when propelled by steam alone the apparatus outside the ship will receive scarcely any shock from the sea.
This new invention entirely removes the great objection of feeding the boiler with salt and foul water, and not one-sixth part of the room for fuel, or of weight of machinery now used, will be required; it is also much more simple and safe, not only for navigation, but for all other purposes where locomotive power is required, and will supersede all annual power, as the objections of weight, room, and difficulty of getting and of carrying water in locomotive engines is entirely removed. It will therefore prove an investigation of greater utility to the public than anything yet introduced.
I have to beg the great favour of your Lordships appointing not only scientific but practical engineers to inspect my plans, that you may be perfectly satisfied of their utility, not only in theory, but also as to the practicability of carrying the same into full effect.
The petition in June, 1830, for the loan of a Government hulk, hung fire up to January 1832, when an attempt was made to move the Lords Commissioners of the Admiralty by the force of numbers.
We, whose names are hereunto subscribed, have known Mr. Richard Trevithick, of Hale, in the county of Cornwall, for a period of years, and during which time his conduct has merited our unqualified approbation. As an engineer of experience and eminence few, if any, can surpass him, and his present improvement of the steam-engine seems to out vie all others. We therefore, in justice to his talent, strongly recommend to the Lords Commissioners of the Admiralty that he may be permitted, at his own costs and charges, to fit and make trial of his engine in one of His Majesty's vessels.
Dated in London this 27th day of January, 1832.
This was sent to Mr. Davies Gilbert, who on the same date suggested the following:—
RECOMMENDATION OF MR. RD. TREVITHICK, January 27, 1832.
We have not any doubt or hesitation in recommending Mr. Richard Trevithick as a man of extraordinary powers of mind, and of fertility of invention.
Cornwall owes to him much of the improvements that have been made on Mr. Watt's engine —improvements that have reduced the consumption of coal to a third ; nor have his exertions been confined to steam-engines alone. He now proposes to make the same water act over and over again by alternate expansion and contraction, which plan, if it succeeds, will be found of immense importance to vessels and locomotive engines.
Understanding that Mr. Trevithick is desirous of making the experiment at his own expense, we clearly recommend that facilities may be afforded him. 
This paltry question with the Admiralty indirectly produced more trustworthy evidence of the great importance of Trevithick's inventions than all that has been written of him under the professional terms Engineers, and Engineering.
The names are not given of those who believed that he had, as an established fact, reduced the consumption of coal in the Watt engine to one-third; they were not Cornishmen, or they would not have misspelt the word Hayle, but they understood the great value of using the same fresh water over and over again in marine steam-engines. Mr. Mills, who had taken an active part in the screw-propeller experiments in 1815, was again interested in the proposed trial in a Government ship, and wrote,
I have just left Captain Johnstone; he has communicated with Fawcett and Co., Barnes and Miller, and with the firm of Maudslay. He has had his mind disturbed again by Maudslay about the greater quantity of water required to condense steam at higher temperatures; I repeated the same as yourself, about the cylinder full of steam, atmosphere strong however, he appears quite different to what he was on Friday.
Such a clique of professional friends would sink a stronger man than Trevithick. A year or two from that time the writer designed a high-pressure steam-engine suitable for a steamboat, and on presenting it to the eminent marine-engine builders whom he served, was told that the lightness of the engine would cause less profit to the makers. Their bills were based on the pounds weight delivered, and new designs necessitated new patterns and new troubles. It was unreasonable to expect those makers of marine steam-engines to report that Trevithick knew better than they did. They knew of his screw-propeller experiments fifteen years before, but they in no way benefited him, and the Admiralty Captain was either a tool in their hands, or powerless without them.
The primary object, when the loan of the ship was asked, was the using for marine purposes a high-pressure steam tubular boiler, combined with tubular condenser, supplying or returning its water as feed, thereby avoiding the use of salt water in the boiler and this steam-engine, as shown in his patent of 1831, was to be applied either to his screw, or his duck's foot, or other propeller but during the year or two of suspense, other schemes for propelling ships had occupied his thoughts, resulting in the patent of 1832.
Steam Engines, 1832.
NOW KNOW YE, that in compliance with the said proviso, I, the said Richard Trevithick, do hereby declare the nature of my said invention, as regards the improvement or improvements on the steam-engine, to consist in interposing between the boiler and the working cylinder, in a situation to be strongly heated, a long pipe formed of a compact series of curved or bent pipes, which I denominate the dry pipes, or steam-expanding apparatus, through which dry pipes I cause the steam, after it has been generated in the boiler in contact and consequently saturated with water, to pass with very great velocity, in order that it may imbibe a copious supply of additional heat without any addition of water, and by this additional heat to be expanded into a greater bulk of steam, of about the same expansive force that it had acquired in the boiler, by which means I obtain a greater volume or steam for use in the working cylinder than the boiler alone would supply; and in order still further to augment this volume of steam, I place the working cylinder within a case constituting a part of the flue or chimney, that the cylinder may be kept considerably hotter than the steam employed in it by absorbing a great portion of the beat remaining in the flue after having heated the boiler and the dry pipes, which heat would otherwise pass away out of the top of the chimney and be wasted, but by this arrangement is converted into a useful power by further expanding the steam in the cylinder.
And I do further declare, that in carrying this part of my said improvement into effect, I do not find it necessary to confine myself to any particular form of boiler, or arrangement of pipes, in which the steam is to be heated but by preference, as being very compact in form, and economical of fuel in using, I make my boiler of a number of upright pipes, standing upon and communicating with a tubular ring placed around and a little below the fire-grate; these pipes all surround the fireplace, except two or three, the lower ends of which are elevated above the fire-door, but connected at the bottom by a branch pipe united to one of the adjoining upright pip's, thereby leaving an opening or place of access to the fire. These pipes all extend upwards to the height of several feet, according to the quantity of steam required to be raised, combined with local convenience, for it is obvious that the power of this boiler to raise steam may be increased either by increase of the length of the pipes, of their diameters, or of their numbers. And I do lay upon the upper ends of the pipes hereinbefore described and connect with them a tubular ring similar to that upon which the pipes stand, the two rings and the upright pipes forming together a vessel in which water has free communication by means of the bottom ring to stand at the same level in all the pipes, and the steam has free communication to pass from all the pipes into the upper ring and I do, for the sake of obtaining great heat, place my system of dry pipes over the fire, and within the circular row of upright pipes of the boiler hereinbefore described; and I form my dry pipes in pairs, each pair constituting the figure that is well understood by the term inverted syphon; and I unite several of these syphons together by short bent pipes at the top, so as to constitute one long zig-zag pipe, through which the steam must successively pass down and up the alternate legs of each syphon with great velocity, necessary for the rapid absorption of heat in its passage from the boiler to the working cylinder of the engine, the working cock, valves, or slide of which being united by a pipe of communication with that leg which is last in the succession of syphons; and I unite the first in succession of these inverted syphons with the upper tubular ring of the boiler by means of a bent pipe, in which a throttle-valve or cock is placed in order to limit the supply of steam, that it may have space in the dry pipes and working cylinder to expand in proportion as it receives additional heat; and I fix a safety-valve in communication with the boiler, and another in communication with the dry pipes; and I place around outside the boiler, at a small distance from the upright pipes, two cylindrical casings, one within the other, and fill up the space between the two casings with sand, ashes, or other material which conducts heat but slowly; and I close up the upper end of the casings over the boiler and the dry pipes with a covering in the form of a dome, and out of this enclosure I make the flue to pass to and around the working cylinder of the engine, whence the flue carries the smoke and little remaining heat away in any convenient manner; and I make my boiler-pipes, rings, and casings by preference of iron or copper, and my dry pipes of copper or other strong metal not liable to rapid oxidation by heat when in contact with steam; and I supply my boiler with water by means of a forcing pump, so adjusted as to keep the water of the proper height.
And I do hereby further declare, that the nature of my said invention, as regards the improvements in the application of steam-power to navigation, consists in the drawing of water into a receptacle placed near within the stern of the navigable vessel, which water is drawn in through an orifice in the stern with a moderate degree of velocity in the direction of the course of the vessel, and ejected with great force and speed in a direction opposite to the course of the vessel through the same orifice, reduced to about a quarter of the area by means of a valve opening as the water enters, and partially shutting as the water is ejected and thus I propel the vessel with great force, derived from the recoil of the water set into rapid motion in a direction opposite to the course of the vessel, the rapidity of the jet of water to be at least equal to double the required speed of the vessel to be navigated.
And I further declare, that by preference I effect the purpose of receiving and of ejecting the water, and of deriving a motive force from its recoil, by means of a large vertical cylinder of cast iron or other metal, closed at both ends, in which a piston is forced up and down by a piston-rod sliding through a stuffing box in the lid, which piston-rod receives its motive force from a steam-engine; and I fix a tube into the after side of this cylinder, near the bottom, in communication with the space below the piston, which tube leads through the stern of the vessel, as low down as practicable, and opens on one side of the rudder and I fix another tube into the after side of this cylinder, near the top, in communication with the space above the piston, which tube also leads through the stern of the vessel, as low down as practicable, but opens out on the other side of the rudder and I place in the mouth of each of these tubes a valve opening inwards, to allow the water free entrance, equal to the bore of the tube, and partially shutting when the water is ejected, so as to reduce the opening through the stern to about one-fourth of the area of the tube.
And I do hereby further declare, that the nature of my said invention, as regards the improvement in the application of steam-power to locomotion, consists in the application of such a boiler, together with the expanding apparatus as aforesaid, to locomotive engines, whereby a diminished weight of boiler and quantity of water and fuel is obtained; and in further compliance with the said proviso, I, the said Richard Trevithick, do hereby describe the manner in which my said invention is to be performed, by the following description of its various parts in detail, reference being had to the drawing annexed, and to the figures and letters marked thereon, that is to say:—
Description of the Drawing. [Plate XVII.]
Figure 1 represents a series of vertical sections through the various essential parts of the boiler, the dry pipes, the steam-pipe, the working cylinder, the propelling cylinder, and the flue, together with sections and views of other minor parts, serving to show the connections of the essential ones. The places at which these sections are taken are shown in Figure 2 by the dotted line from A to B, from B to C, from C to D, and from E to F. Figure 2 represents a plan of Figure 1, with the top coverings of the boiler and working cylinder removed. Figure 3 shows the manner of uniting the shorter upright pipes over the fire doorway with one of the adjoining ones, so as to give free circulation of the water in all the pipes. Figure 4 represents three pairs of syphons, which in their places stand in a circular form, but in this Figure are shown as spread out into a plane, in order the better to explain their structure and joinings. Similar small letters and numbers of reference are used to denote similar parts in all the Figures; a, the upright boiler-pipes, the upright and lower ends of which are contracted to leave room for bolt-heads and nuts, without throwing the pipes too far asunder; b, the tubular ring having a flanch projecting inwards and outwards at the upper side, perforated with apertures upon which the upright pipes are bolted, and another flanch at the bottom, projecting inwards, to bolt the ring down to the foundation plate; c, the foundation plate; d, the fire-grate; e, the fire doorway; f, the upper tubular ring, having a flanch at the bottom projecting inwards and outwards, and perforated with apertures corresponding with the tops of the upright pipes upon which the tubular ring lies, and to all which it is bolted; g, the level of the water in the boiler-pipes; h, the dry pipes formed like inverted syphons, so as to require no joining at the lower part near the fire; one leg of each of the two syphons shown in Figure 1 is in section, and broken near the bottom; an outside view of the other leg appears partly behind the section; k, the short bent pipes, each bolted to two syphons, to unite them into one continuous pipe; l, the bent pipe uniting the upper tubular ring with the first in succession of the syphons; the proper situation for this pipe is that shown in Figure 2, but for the sake of clearness and simplicity in the drawing, it is shown in Figure 1 as if on the left-band pipe and syphon; m, the throttle-cock on the bent pipe l; n, the safety-valve lever, and weight on the same; p, the pipe of communication from the last in the succession of syphons to the working cylinder of the engine; r, the throttle-cock in the pipe p; s. a four-way cock, worked by the hand-gear, to direct the steam alternately under and over the piston; t, the safety-valve in communication with the dry pipes; u, the two cylindrical casings surrounding the boiler-pipes, the space between the two being filled up with a slow conducting medium; v, the domical covering over the cylindrical enclosure; w, the flue leading out of the enclosure into the casing of the working cylinder; x, the casing of the working cylinder forming a continuation of the flue; y, the further continuation of the flue to the chimney; z, the waste-steam pipe leading into the chimney; 1, the steam-pipes leading from the working cock into the top and bottom of the working cylinder; 2, the working cylinder; 3, the piston with metallic packing; 4, the piston-roil passing down through a stuffing box at the bottom of the working cylinder, and also continuing downwards, to form the rod of the propelling piston; 5, the propelling cylinder; 6, the water or propelling piston; 7, the upper aperture leading to one of the tubes opening through the stern of the navigable vessel; 8, the lower aperture leading to the other tube, opening also through the stern of the navigable vessel; these apertures are made as wide as the cylinder will allow, in order that they may have but little depth, and not occasion an inconvenient length of the propelling cylinder; 9, a frame supporting the steam-cylinder upon the propelling cylinder; 10, the feed-pump for supplying the boiler with water; 11, an arm fastened on the piston-rod to work the feed-pump and hand-gear; 12, the hand-gear.
Now, whereas I claim as my invention, firstly, the interposing between the boiler and the working cylinder of the steam-engine a long man curved heated pipe, through which the steam is forced to pass with great rapidity without being permitted to come in direct contact with water, by which arrangement the steam is made to absorb additional heat, and at the same time allowed to expand itself into a greater volume.
Secondly, placing the working cylinder of the engine within such part of the flue or chimney as shall ensure the cylinder to be kept hotter than the steam used in it, by which means the expanding of the steam is still further promoted.
Thirdly, propelling a navigable vessel by the force of the recoil produced from water received with a moderate degree of velocity, into a receptacle near within the stern, in the direction of the course of the vessel, and ejected with great velocity in a direction opposite to that course, the velocity of the jet being at least double the required speed of the vessel to be propelled, provided always that the saute be effected in manner herein- before described.
Fourthly, applying a boiler combined with a steam expanding apparatus, as before described, instead of a boiler alone, to a locomotive engine, whereby the power of the steam is applied after the steam has undergone the expanding process, and whereby a diminution is effected in the weight of the boiler, and in the weight and consumption of water and of fuel.
The two great objects in this 1832 patent were superheating steam in tubular boilers, and propelling ships by forcing a stream of water from the stern at a speed of at least double that of the vessel. Similar ideas may be traced in his patent of 1815, where a tubular boiler gave superheated steam, and in 1809 his patent for propelling steamboats consists of a tube of considerable length disposed horizontally in the water, and the stroke of rowing is made by means of a piston with valves.
An engine of 100-horse power was ordered in Shropshire to be placed on board the Government ship to test the value of those patents of 1831 and 1832. One consequence was that a gentleman who had helped this scheme with his money wrote:—
My case with Trevithick is strictly this; he was represented to me as a man of property; and as to his talents for mechanics, no man could be in his company long without being struck with them. I was induced to trust him to the amount of nearly £500, and I then learned for the first time that it was only on the possible contingency of a grant from Government that he relied for the payment of my claim.
A company called the New Improved Patent Steam Navigation Company was formed, of which Trevithick was a member, though apparently not a subscriber, for a note in November, 1831,, informed him that "if in seven days he did not pay up his calls, his shares would be entirely forfeited." This company, among other proposals, opened negotiations for sending steamboats to Buenos Ayres to help in the commerce of the port and inland river.
In 1832 the Waterwitch Company made experiments with those plans, propelling by forcing water through pipes, since which a Government ship of war called the 'Waterwitch' has been so propelled. Twenty years ago the writer saw steamboats so propelled in daily use on the Meuse; they needed no rudder, for by turning the mouth of the exit-water pipes on either side of the ship it was made to turn in its length, or even to move side ways.
Messrs. John Hall and Sons, of Dartford, also experimented on these two patents, and from this the tubular condenser was called Hall's Condenser. I think the boat was first tried in was called the 'Dartford.'
Trevithick's difficulties in urging so many and great changes in marine propulsion may be estimated by the acts of other engineers.
Mr. Rennie was engaged for many years in urging the introduction of steam-power in the Royal Navy. In 1817 we find him writing to Lord Melville, Sir J. Yorke, Sir D. Milne, and others on the subject. In July, 1818, he laments that he cannot convince Sir G. Hope or Mr. Secretary Yorke of their utility, but that he is persuaded their adoption must come at last. On the 30th May, 1820, he writes James Watt, of Birmingham, informing him that the Admiralty had at last decided upon having a steamboat, notwithstanding the strong resistance of the Navy Board. 
So that Mr. Rennie, as professional adviser of the Navy Board, had to persuade for three years, with a knowledge of Trevithick's prior experiments, before active steps were agreed to; for twelve years had then passed since Trevithick's nautical labourer and iron steamboat had been tried on the Thames, and five since his experiments with the screw-propeller.
An article in 'The Times' gives in strong contrast the relative value of screw and paddle-wheels as propellers. The 'Syria' was originally a paddle-wheel steamer, having oscillating cylinders worked with steam of 25 lbs. on the inch, and Hall's tubular condenser; after a time the peddle-wheels were removed for a screw-propeller, driven by two steam-cylinders side by side, of different diameters, the high-pressure steam exerting its full force in the small cylinder, and then expanding in the larger cylinder. All the leading features in this improved steamboat of the present day, such as high-pressure expansive steam in one or two cylinders, with tubular condenser and screw-propeller, had been publicly proved by Trevithick fifty years before.
Screw against Paddle. - An interesting and important trial trip has recently been made, which serves to exhibit the advantages of the screw over the paddle as a means of propulsion for ocean-going steamships. In 1863, the steamship 'Syria,' of 1,998 tons, was built for the Peninsular and Oriental Company by Messrs. Day, Summers, and Co., and fitted with paddle-wheel engines of 450-horse power. The 'Syria' then attained a speed of 13.038 knots per hour, and the consumption of coal was at the rate of 45 tons per diem. The builders have lately converted her into a screw-steamer (for carrying the mails between Southampton and the Cape of Good Hope), who, without in any way disturbing the configuration of the hull, have fitted the 'Syria' with compound inverted engines of 300 nominal horsepower. These engines have two cylinders, respectively of 36 in. and 72 in. diameter, with a stroke of 4 ft. 2 in. On Monday last the 'Syria' attained an average speed of 12.637 knots, with a consumption of coal equivalent to 18 tons per diem; thus showing a difference of only 0.401 knot per hour, with a lessened power of 150 horses, and a saving in consumption of coal of 27 tons per diem; while the carrying capacity of the ship, arising from the economy of space in the engine-room, has been enormously increased, as she can now stow 1,200 tons of cargo against 500 tons previously. 
Mr. Husband, of the firm of Harvey and Co., of Hayle, has obliged me with the annexed sketch (Plate XVIII.) of a modern high-pressure steam expansive compound marine engine, with surface condensers, on which the grandsons of Trevithick are now working, to he placed in the 'Batara Rayon Syree,' an iron yacht for an Indian Rajah, embracing the modern improvements of direct-action compound engines, and illustrating the principles which governed the constructors of the 'Syria.'
The first glance shows a seeming resemblance in outline to Trevithick's patent drawing of 1832, having one cylinder above the other but a closer examination proves the application of the principles of his patents of 1815 and 1831, embracing screw-propeller, direct-acting engines, tubular boilers, high-pressure steam used expansively, and condensation by cold surface preventing the necessity of using salt water in the boilers. This engine, in outline, has a strong likeness to Trevithick's engines, going back even to his first patent of 1802,  followed by the direct-action high-pressure steamy yacht of 1806,  and again in 1808  by the iron steamer with direct-action long-stroke cylinders, with highly expansive steam and surface condensers, to which, in 1815,  was added the patent compound expansive steam pole and piston engine and screw-propeller, embodying during the first fifteen years of the present century, both in principle and in detail, the most approved form of marine steam-engine with fewness and simplicity of form of moving parts; but compare it with the Watt patent engine, and its difference is obvious; no beam or parallel motion, no injection-water necessitating the air-pump, no low-pressure steam. The late Mr. William Wilson, of Perran Foundry, son of Boulton and Watt's financial agent in Cornwall, informed Mr. Henwood that he was with Mr. Watt when some one stated that Mr. Trevithick was working his engine with steam of 40 lbs. on the inch when Mr. Watt replied, "I could work my engine with steam of 100 lbs. to the inch, but I would not be the engineman." 
Progressive experience, with increasing demand for economy and speed, have caused the principles and the details of Trevithick's steam-engines to be matters of national importance seventy years after their discovery, for as far back as that he used highly-expansive steam,  and on the question of a separate cylinder for expansion as used in the modern steamboat combined engines, he wrote,
I think one cylinder partly filled with steam would do equally as well as two cylinders; that one at Worcester shuts off the steam at the first third of the stroke, and works very uniformly with a considerable saving of coal. 
Those modern marine engines use about the same steam pressure and expand about in the same proportion. With the direct action from the piston-rod to the crank-shaft, the multi-tubular boiler and screw-propeller, and the surface condenser perfected in 1831 and 1832, at which time his construction of a marine steam-engine would have been just what it now is forty years later. Those latter patents also embrace the principle of super-heating steam, practically shown many years before,  and still used by marine engineers of modern times.
In tracing the wisdom of his designs just before the close of an eventful life, reference may be made to the trial of a common road locomotive in 1871:—
Experimental trip of the Indian Government steam train engine, 'Ranee,' from Ipswich to Edinburgh. — The results of the trial with the 'Chenah,' though satisfactory so far as the engines proper were concerned, were vitiated by the failure of the boiler; on the completion of the second engine, the 'Ranee,' the field boiler and variable blast-pipe were used; the boiler is about 4 feet diameter at the bottom and 8 feet high. 
The form and dimensions of the exterior of the Ranee tubular boiler are very similar to Trevithick's patent drawing and specification of 1832 even the variable blast-pipe was used by him in 1802. 
The last years of Trevithick's eventful life were chequered with hopes and disappointments when, in the early part of 1830, he wrote to his friend Gerard:—
This morning I called here for the purpose of forwarding my information to the committee of the House. I called on Mr. Thompson to inform him what Mr. Gilbert said respecting it. His answer was, that the direct method would be by forwarding a petition in the way proposed when at the lobby. In consequence, I have forwarded the petition to Sir Matthew Ridley. Yesterday I took the coach to Highgate, by way of Camden Town, and of course had to walk up Highgate Hill. I found I was able to walk up that hill with as much ease and speed as any of my coach companions. However strange this maggot may appear in my chest and brain, it is no more than true. I wish among all you long-life-preserving doctors you could find out the cause of this defect, so as to remedy this troublesome companion of mine.
His health was breaking down, and his petition for a gift from the public purse, so hopefully commenced two years before, was doomed, after another year's bandying from pillar to post, to be forgotten and unanswered.
December 26th, 1831.
I and sorry to find that you have not any prospect of assistance from Government. I have not any copy or memorandum of my letter to Mr. Spring Rice, but it was to the effect of first bearing testimony to the large share that you have had in almost all the improvements on Mr. Watt's engine, which have altogether about trebled its power; your having made a travelling engine twenty-eight years ago; of your having invented the iron tanks for carrying water on board ship. I then went on to state that the great defect in all steam-engines seemed to be the loss by condensation of all the heat rendered latent in the conversion of water into steam. That high-pressure engines owed their advantages mainly to a reduction of the relative importance of this latent heat. That I had long wished to see the plan of a differential engine tried, in which the temperatures, and consequently elasticities, of the fluid might be varied on the opposite sides of the piston without condensation; that the engine you had now constructed promised to effect that object, and that in the event of its succeeding at all, although it might not be applicable to the driving water out of mines, yet that for steam-vessels and for steam-carriages its obvious advantages would be of the greatest importance; and I ended by saying that although it was clearly impossible for me to ensure the success of any plan till it had been actually proved by experiment, yet judging theoretically, and also from the imperfect trial exhibited on the Thames, I thought it well worthy of being favoured.
Your plan unquestionably must be to appoint some one with you, as Mr. Watt did Mr. Boulton, and I certainly think it a very fair speculation for any such person as Mr. Boulton to undertake.
It is impossible for me to point out any individual, as never having had the slightest motive with such or with manufacturers in any part of my life, I am entirely unacquainted with mercantile concerns. I cannot, however, but conjecture that you should make a fair and full estimate of what would be the expense of making a decisive experiment on a scale sufficiently large to remove all doubt and that your proposal should be, that anyone wishing to incur that expense should, in the event of success, be entitled to a certain share of your patent; on such conditions some one of property may perhaps be found who would undertake the risk, and if the experiment proved successful, he would be sure to use every exertion afterwards for his own sake. With every wish for your success,
Believe me, yours very faithfully.
The statement of the President of the Royal Society, that the power of the Watt engine had been trebled by Trevithick, brought him no gain. He never troubled himself with politics, but the passing of the Reform Bill caused him to suggest that it should be commemorated by a pillar higher than had ever before been erected. The following memorandum is in his own writing:—
'Morning Herald,' July 11th, 1832.
National Monument in honour of Reform. - The great measure of Reform having become the law of the land, it is proposed to commemorate the event by the erection of a stupendous column, exceeding in dimensions Cleopatra's Needle, or Pompey's Pillar, and symbolical of the beauty, strength, and unaffected grandeur of the British Constitution.
In furtherance of this great object, a public meeting is proposed to be held, of which due notice will be given, to set on foot a subscription throughout the United Kingdoms, limiting individual contributions to two guineas, but receiving the smallest sums in aid of the design.
The following noblemen and gentlemen have signified their approbation of the measure:— His Grace the Duke of Norfolk, of Somerset, of Bedford; the Right Honourable Earl of Morley, of Shrewsbury, of Darlington Lord Stafford; Sir Francis Burdett, M.P.; Joseph Hume, M.P.; H. H. Howard, M.P.; Wm. Brougham, M.P.; J. E. Denison, M.P.; A. W. Robarts, M.P.; J. Easthope, M.P.; General Palmer, M.P.
Design and specification for erecting a gilded conical cast-iron monument. Scale, 40 feet to the inch of 1,000 feet in height, 100 feet diameter at the base, and 12 feet diameter at the top; 2 inches thick, in 1,500 pieces of 10 feet square, with an opening in the centre of each piece 6 feet diameter, also in each corner of 18 inches diameter, for the purpose of lessening the resistance of the wind, and lightening the structure; with flanges on every edge on their inside to screw them together; seated on a circular stone foundation of 6 feet wide, with an ornamental base column of 60 feet high; and a capital with 50 feet diameter platform, and figure on the top of 40 feet high; with a cylinder of 10 feet diameter in the centre of the cone, the whole height, for the accommodation of persons ascending to the top. Each cast-iron square would weigh about 3 tons, to be all screwed together, with sheet lead between every joint. The whole weight would be about 6,000 tons. The proportions of this cone to its height would be about the same as the general shape of spires in England.
A steam-engine of 20-horse power is sufficient for lifting one square of iron to the top in ten minutes, and as any number of men might work at the same time, screwing them together, one square could easily be fixed every hour: 1,500 squares requiring less than six months for the completion of the cone. A proposal has been made by iron founders to deliver these castings on the spot at £7 a ton; at this rate the whole expense of completing this national monument would not exceed £80,000.
By a cylinder of 10 feet diameter, through which the public would ascend to the top, bored and screwed together, in which a hollow floating sheet-iron piston, with a seat round it, accommodating 25 persons; a steam-engine forces air into the cylinder-column from a blast-cylinder of the same diameter and working 3 feet a second, would raise the floating piston to the top at the same speed, or five or six minutes ascending the whole height; the descent would require the same time. A door at the bottom of the ascending cylinder opens inwards, which, when shut, could not be opened again, having a pressure of 1,500 lbs. of air tending to keep it shut until the piston descends to the bottom. By closing the valve in the piston it would ascend to the top with the passengers floating on air, the same as a regulating blast-piston, or the upper plank of a smith's bellows. The air apparatus from the engine should be of a proper size to admit the floating piston with the passengers to rise and fall gradually, by the partially opening or shutting of the valves in the top of the piston. Supposing no springs or soft substance for the piston to strike on at the bottom of the column-cylinder, descending 3 feet a second would give no greater shock than falling from 9 inches high, that being the rate of falling bodies, or the same as a person being suddenly stopped when walking at the rate of two miles an hour. The pressure of the air under the piston would be about 2 lb. on the square inch; the aperture cannot let the piston move above 3 feet a second, but this speed may be reduced to any rate required by opening or shutting the valves on the floating piston.
To Trevithick's soaring genius nothing appeared very small, or very large, or very costly; not even the cast-iron column 1,000 feet high covered with gold. The stone monument of London, 210 feet high, is admired by many; others climb into the cross on St. Paul's Cathedral, 420 feet high; some make a long journey to the great Pyramids, 500 feet high. How much more pleasant would be Trevithick's proposed floating 1,000 feet upward on an air-cushion, controlled by his high-pressure steam-engine, and having, from the loftiest pedestal of human art, surveyed imperial London, to be again lowered to the every-day level at a safe speed, regulated by valves closed by such simple acts as rising from the seat; but should this be neglected, the passage of compressed air escaping from under the piston- carriage would only allow of its descent at a speed of 3 feet in a second, giving but the same shock on bumping the bottom as jumping off a 9-inch door-step.
Perhaps the King in 1833 could not take an active part in advocating a memento of the golden days of reform but this is no reason why the suggestion should have been so slightly noticed in 1862, to erect it in memory of the good and wise Prince Albert.
Various meetings were held, and after nine months the plan had so far advanced as to be placed before the King.
Sir Herbert Taylor begs to acknowledge the receipt of Mr. R. Trevithick's letter, with the accompanying design for a national monument, which he has had the honour of submitting to the King.
ST. JAMES'S PALACE, 1st March, 1833. 
Within two months from the date of the design for a gilded column Trevithick had passed away. His family in Cornwall received a note, dated 22nd April, 1833, from Mr. Rowley Potter, of Dartford, stating that Trevithick had died on the morning of that day, after a week's confinement to his bed. He was penniless, and without a relative by him in his last illness, and for the last offices of kindness was indebted to some who were losers by his schemes. The mechanics from the works of Messrs. Hall were the bearers and mourners at the funeral, and at their expense night watchers remained by the grave to prevent body-snatching, then frequent in that neighbourhood.
A few years after the funeral, the writer was refused permission to go through the works to inquire into the character of the experiments that had been tried, but the working mechanics were glad to see the son of Trevithick, and their wives and children joined in the welcome as he passed through the small town.
Trevithick's grave was among those of the poor buried by the charitable; no stone or mark distinguished it from its neighbours. He is known by his works. His high-pressure steam-engine was the pioneer of locomotion and its wide-spreading civilization. England's mineral and mechanical wealth on land or sea are indebted to its expansive power, its applicability, and durable economy.
His comprehensive and ingenious designs, given to the world seventy years ago,  are still instructive guides and many of his works, dating from the dawn of the present century, remained as active evidences of his skill almost to the present day, with their three-score years,  while some few reaching three-score years and ten still remain good servants  in the solitude of the Peruvian mountains, where no mechanical hand repairs the errors of human skill or the wear and tear of time. 
If these material proof's fail to convince, the reader has but to ponder on the bitterly natural reflections written by himself a few months before his last illness to his friend Davies Gilbert:
I have been branded with folly and madness for attempting what the world calls impossibilities, and even from the great engineer, the late Mr. James Watt, who said to an eminent scientific character still living,  that I deserved hanging for bringing into use the high-pressure engine. This so far has been my reward from the public; but should this be all, I shall be satisfied by the great secret pleasure and laudable pride that I feel in my own breast from having been the instrument of bringing forward and maturing new principles and new arrangements of boundless value to my country. However much I may be straitened in pecuniary circumstances, the great honour of being a useful subject can never be taken from me, which to me far exceeds riches.
- Life of Richard Trevithick by F. Trevithick
- Life of Richard Trevithick by F. Trevithick: Volume 2: Chapter 26
- See chapters xiv. and xv.
- See Trevithick's letter, 7th May, 1815, vol. i., p. 364.
- See vol. i., p. 325, and patent, 1809, p. 302
- See Mr. Newton's letter, vol. i., p. 342
- See 'Illustrated News,' 27th April, 1872.
- In the handwriting of Mr. Davies Gilbert.
- 'Lives of the Engineers' by Smiles, vol. ii., p. 267.
- See 'The Times,' May 20th, 1871
- See vol. i., p. 59.
- See vol. i., p. 327.
- See vol. i., p. 336.
- See vol. ii., p. 103.
- Henwood, Address to the Royal institution of Cornwall, 1871.
- See Trevithick's letter, 22nd August, 1802, vol. i., p. 153.
- See Trevithick's letter, 5th July, 1804, vol. ii., p. 132.
- See Trevithick's letter, 16th May, 1815, vol. i., p. 370.
- 'The Engineer,' 27th October, 1871.
- Trevithick's letter, 22nd August, 1802, vol. i., p. 153.
- The column was suggested in 1862 as a suitable monument to the memory of the late Prince Albert.
- See 1802 patent, vol. i., p. 128.
- See vol. i., pp. 222, 100, 82, 184.
- Agricultural engine, vol. ii., p. 68.
- See vol. ii., p. 220.
- Mr. John Isaac Hawkins.