Francis Trevithick

GUN-CARRIAGE—IRON SHIPS—HYDRAULIC CRANE—ICE MAKING—DRAINAGE OF HOLLAND—CHAIN-PUMP—OPEN-TOP CYLINDER—HAYLE HARBOUR—PATENT RIGHTS—PETITION TO PARLIAMENT.

Trevithick's Gun-carriage and Friction Slides

Trevithick's Gun-carriage and Friction Slides, 1827.

"Richard Trevithick, of the parish of Saint Erth, in the county of Cornwall, civil engineer, maketh oath and saith that he hath invented new methods for centering ordnance on pivots, facilitating the discharge of the same, and reducing manual labour in time of action. That he is the true inventor thereof, and that the same hath not been practised by any other person or persons whomsoever to his knowledge or belief.

"Sworn, 10th November, 1827, before me, Rd. Edmonds."

"This gun is worked by machinery balanced on pivots giving it universal motion, by one man, with the facility of a soldier's musket. On one side a man puts in a copper charge of powder; on the opposite side a man drops a ball in a bag down the gun, as it stands muzzle up. The gunner, who sits on the seat behind the gun, points it and pulls the trigger. The firing causes it to run up an inclined plane at an angle of 25° for the purpose of breaking the recoil; it runs down again with its muzzle at the port, requiring no wadding, swabbing, cartridge, or ramming, but runs in, out, primes, cocks, shuts the pan, and breaks the recoil of itself; and by three men can be fired three times in a minute with accuracy. The gun-carriage is a tube 3 feet long and 3 feet diameter, made of wrought-iron plate 1/4 of an inch thick, centered on a pivot to the deck, with the gunner's seat attached, from which he looks through the case. As the gun requires no tackle, and but a man on each side to work it, only a space of 5 feet 6 inches is required from centre to centre of ports, therefore a single-deck ship will carry a greater number of guns than are now carried on a double-deck ship, be worked with one-third of the hands, and be fired five times as fast as at present. A frigate would mount fifty 42-pound guns on one deck, with 150 men, and would discharge in the same time a greater weight of ball with greater precision than five 74-gun ships."[135]

"Hayle, Cornwall, 21st February, 1828.

"My Lord Cochrane,[136]

"With great pleasure I read in the papers the announcement of your arrival again in England, and am much gratified to find a person of your superior natural and practical talents, so rare to be obtained, to whom I may communicate my views.

"I have proposed to Government to build an iron ship, and a gun on a new principle, which are to undergo an investigation, and have lodged a drawing of the ship and a model of the gun with my friend Mr. Gerard, a gentleman who returned with me from America, and who will present to you this letter with the above-mentioned drawing and model.

"I have had an iron boat made for the purpose of sending it to London, to show the method of constructing ships on this plan, roomy, strong, and cheap. Also a wrought-iron ship with a steam-engine on an improved principle, which in a few days will be laid on the stocks at the Hayle Foundry iron manufactory."

Though Lord Cochrane was just the person to be interested in such schemes, it does not appear that he took any part in them. At that time he was at work on his own particular ideas for marine propulsion.

The recoil gun-carriage was his first occupation after twelve years of travel in countries where mechanical appliances were less thought of than weapons of war. He commenced this, his second era of inventions, with what he called a new thing, though it was but an extension of his schemes of 1809, when he patented iron vessels, hollow sliding masts and yards, self-reefing sails, and sliding keels.

The model gun was of brass, resting on a railway formed of two inclined bars of iron, up which the recoil propelled it into a convenient position for cleaning and loading. Its own gravity caused it to fall into the required place for being again fired. The slides also served as friction-bars to regulate the recoil.

The gun and the slides carrying it were enclosed in a wrought-iron box, having openings in the front and rear for the passage of the muzzle and the breech. The muzzle front of the box was pivoted to the deck by a strong bolt as a centre of motion, whilst its rear was supported on two small wheels resting on the deck, allowing the gun to change its line of horizontal fire by sweeping from the centre pivot. The gunner's seat moved with the carriage, from which he could elevate or depress the muzzle by a lever. The gun was self-priming and self-cocking; the powder charge was enclosed in a copper case. Captain Moncrieff's patent gun-carriage of the present day is described in words somewhat like those used by Trevithick forty years before. "The recoil lifted a weight smoothly and without friction; the gun and the weight were held in the position arrived at by a catch until the gun was loaded and ready to fire again."[137]

The iron boat mentioned in his note to Lord Cochrane as being made at Hayle, was "for the purpose of sending to London to show the method of constructing ships on this plan, roomy, strong, and cheap," and was thus spoken of in a newspaper of the 26th April, 1829. "The 'Scotsman' alludes to the intended construction of iron steamboats at Glasgow by Mr. Neilson:—"For fear of the public being misled on this subject, we beg to state that so far back as last Christmas twelvemonths we saw Trevithick, of Cornwall, superintending the construction of an iron man-of-war launch, with the avowed intention of applying a similar principle of construction to the building of fast-sailing iron steamboats." This intimation, in 1829, to the since famous Glasgow iron-ship builders, that they could not claim the invention because Trevithick had made such a boat in 1827, was probably in ignorance of Trevithick's patent and models of 1809,[138] explaining the advantages of ships of iron, either under sail or under steam, for commerce or for fighting-ships. The improved high-pressure steam-engine then in hand for iron ships was but the perfecting of his plans of twenty years before.[139]

The foregoing may be classed either under cannon or steam-engine; Trevithick combined them under the general laws of expansion by heat. Three years had passed since the committee of artillery officers sitting on his gun had given a verdict of no go; yet the subject was not forgotten, and his calculations enabled him to discover the explosive force, and the speed of the projectile in different parts of the gun, things which are now ascertained by mechanical tests and measures.

If a 7-inch cannon 9 feet long loses by absorption of heat during the time of the passage of the shot to the muzzle one-half of the expansive force of the powder, it is time to wrap our guns as well as our steam-engines in non-conductors. The greater heat of exploded powder than of steam caused eighty-eight times the amount of loss from abstracted heat, and yet the force from a pound of carbon in powder, was fourteen times as much as the Watt engine gave from a pound of coal.

The reduction of friction by the use of an air-vacuum engine for working cranes, as designed by Mr. Linthorn, in lieu of an air-pressure engine, was doubted by Trevithick.

The Mont Cenis pneumatic-pressure machines which the writer saw at work lost much power by friction before experience had taught remedies. The pneumatic vacuum tubes which propelled the trains on the South Devon Railway, failed to give the power that was expected. Sir William Armstrong's hydraulic cranes, brought into use not many years after the date of Trevithick's letter, have been found effective. The writer, not knowing that Trevithick had before recommended hydraulic cranes for warehouses, accompanied Sir William over his works, then being erected near Newcastle-on-Tyne, and talked with him on the detail of his crane designs.

Trevithick thought of giving circular motion to the crane chain-barrel by the attachment of a screw-propeller, acted on by the force of a current of water at a pressure of 30 or 40 lbs. to the inch. Sir William Armstrong's arrangement was quite different; the merit due to Trevithick was for having pointed out the suitability of water as a means of conveying power through warehouses where fire was inadmissible.

Trevithick's ideas for making ice have since been patented and made useful, though the detail of the operation has been improved by experience.

The Dutch, extending the use of steam on the Rhine and also in sea-going ships, wished Trevithick to see what was going on in Holland, where his nephew, Mr. Nicholas Harvey, was actively engaged in engineering. He had not money enough for the journey, and borrowed 2l. from a neighbour and relative, Mr. John Tyack. During his walk home a begging man said to him, "Please your honour, my pig is dead; help a poor man." Trevithick gave him 5s. out of the 40s. he had just begged for himself. How he managed to reach Holland his family never knew; but on his return he related the honour done him by the King at sundry interviews, and the kindness of men of influence in friendly communion and feasting.

In this mere outline of a life it is impossible to go fully into the merit of Trevithick's plans for doubling the land surface of Holland. A drainage company was formed in London with a board of directors, some of whom thought that a new kind of engine should be invented and patented as a means of excluding others from carrying on similar but competing operations. Trevithick, always ready to invent new things, though never forgetting his experience with old things, instinctively returned to the Dolcoath engines, and recommended them as suitable for the pumping work; but finally a new design was determined on, and Harvey and Co., of Hayle, received orders for the construction, with the greatest possible dispatch, of a pumping engine for Holland.

This happening shortly after the writer had been taken from the Bodmin school, he was desired to help in the erection of this engine, and after working-hours made a drawing of its original form.

Plate XV. a, iron barge; b, wood frame supporting pump; c, open-top steam-cylinder 3 feet diameter, 8-feet stroke; d, piston guide-wheel; e, connecting rod; f, fly-wheel; g, cranked axle working air-pump bucket; h, connecting rod for air-pump bucket; i, air-pump; j, condenser; k, steam and exhaust nozzles; l, eccentrics working steam and exhaust valves; m, steam-pipe; n, cylindrical boiler, with internal fire-tube; o, external brick flues; p, chimney; q, feed-pump; r, feed-pipe; s, cup or rag-wheel; t, rag-chain, with iron balls; u, pump-barrel, 3 feet diameter; v, wheel guiding balls into bottom of pump-barrel; w, launder.

After a few successful though noisy trials, an alteration was made in the endless chain and in the guide-roller near the pump bottom. An amount of slack in the chain caused the balls to knock on passing this roller before entering the pump bottom. A chain having long links or bars of iron of uniform length, from ball to ball, jointed together by cross-pins, was substituted for the short link chain, and passed over a revolving hollow square frame at the bottom of the pump, in place of the curved roller-guide in the drawing. Each of the four sides of this square hollow frame was of the same length as the jointed link, and the balls lay in the hollow of the frame without touching it, contact being only on the links. The balls were thus guided directly into the bottom of the pump on their upward course with a rigid chain, and the swing and knocking was avoided. This pump was in principle the traditional rag-and-chain pump of a hundred years before; yet no trace of its use is met with during Trevithick's life in Cornwall. The early pump had rag balls, in keeping with the mechanical ignorance of the time, and suitable to man's power.

Trevithick's pump with iron balls raised "7200 gallons of water 10 feet high in a minute with 1½ lb. of coal,"[140] retaining all the original simplicity of the earlier rag-pump, having uniform circular motion and constant stream, without the use of a single valve. The engine and pump are thus described by him:—

It was something like the Newcomen open-topped cylinder of a hundred years before, but with a heavy piston, on the top of which a guide-wheel equal in diameter to the cylinder turned on a pin, to which the main connecting rod was jointed. The guide-wheel prevented any tendency to twist the piston from the angular positions of the connecting rod, and allowed the crank-shaft to be brought comparatively near to the cylinder top. The boiler was cylindrical, of wrought iron, with internal fire-tube and external brick flues; and gave steam of about 40 lbs. on the inch above the atmosphere, which, acting under the piston, caused the up-stroke, an expansive valve reducing the average pressure in the cylinder by one-half. The down-stroke was made by the atmospheric pressure of 14 lbs. on the inch, on the piston, its lower side being in vacuum, together with the weight of the thick piston and connecting rod, and the momentum of the revolving parts.

My readers must not suppose that this was an attempt to revive the discarded Newcomen engine; the likeness was only apparent; its power was mainly from the use of strong expansive steam, giving motion in the up-stroke through a rigid connecting rod, with controlling and equalizing crank and fly-wheel. It was not, as the Newcomen,[142] dependent for its power on the atmospheric pressure; and having no cylinder cover, or parallel motion, or beam, was not a Watt engine, though it had the Watt air-pump and condenser.

The Dolcoath engines continued to work with open-topped cylinders a quarter of a century after the Watt patent; and when they had passed away, many of Trevithick's high-pressure steam-engines retained the same form of outline, but had neither cylinder covers, parallel motion, air-pump, nor vacuum. The agricultural engines of 1813[143] and the South American engines of 1816[144] had neither cylinder cover nor any other part of the Watt engine, yet they successfully competed with it in power, economy, and usefulness.

This design reveals a stumbling-block that superficial people fall over. The boiler in the boat was surrounded by brick flues, while a life-long claim of Trevithick's is that before his tubular boiler with internal fire, there could not be a successful steamboat, because brick flues were dangerous in sea-going vessels, but in an iron boat in smooth water it answered its purpose without in any respect falsifying Trevithick's former claims or plans.

The chain pumping machine was in an iron barge, the 36-inch diameter pump fixed just outside the bow, its lower end a foot in the water; its height of 8 or 9 feet enabled the water from the pump-head to flow through launders over the banks of the lakes to be drained. Some of the directors came to Hayle to see it work, and were well pleased at the constant stream of water rushing from the foaming pump-head into the launders. The large size of the rag-wheel gave the rapidly revolving chain and balls a great speed. In passing through the pump each ball forced upwards the water above it, and drew up after it the following water; before any ball had passed out at the top of the pump the following ball had entered its bottom. The directors having desired the writer to take the engine to Holland and set it to work with the least possible delay, adjourned for refreshment before starting for London. In those few minutes differences arose, resulting in the engine remaining for months in the barge, and then going to the scrap heap.

Years afterwards others acted on Trevithick's drainage ideas, and Harvey and Co. built Cornish pumping engines with steam-cylinders 112 inches in diameter, similar in principle to the Dolcoath engine[145] of 1816, which effectually drained the Haarlem lake.

The Rhine during 100 years, in its passage through the low flat lands, had by deposit raised the level of its waters 5 feet, threatening to overflow the embankments and drown the surrounding country, that to a large extent was at a lower level than the river. All drainage from such land had to be pumped over the river bank, in many places 10 feet above the cultivated surface. Windmills had been used as pumping power, and a company had contemplated laying out 700,000l. in windmills and canals for drainage.

If the surface water averaged 18 inches in depth yearly, Trevithick could by steam-engines drain an acre of land by the consumption of a bushel of coal yearly. Four engines with cylinder of 63 inches in diameter would drain 160,000 acres, and four smaller engines in barges with suitable apparatus were to cut canals and construct embankments. The deposit of a hundred years was also to be removed, and the Rhine deepened 6 feet for a breadth of 1000 yards, and a length of 50 or 60 miles, by steam-dredgers, as used twenty years before in deepening the Thames,[146] to be fixed in iron ships of a thousand tons burthen. The cost of dredging from the bed of the river into a barge would be 1d. per ton; but this would be more than repaid by making with it an embankment, enclosing the Zuyder Zee, which would then in its turn be drained and made pasture land.

Before leaving for America he had reported on the best means of improving St. Ives Bay.[147] Hayle Harbour was a branch of it, and he now suggested to Mr. Henry Harvey methods for deepening and improving it. A rival company of merchants and engineers, known then as Sandys, Carne, and Vivian, after many fights had recourse to law on the question of the course of a stream which had been changed by alterations during the making of wharfs and channels for ships.

Trevithick made a model in wood, movable layers of which indicated changes of level caused by workmen at different periods, giving a different course to the river bed. Mr. Harvey's counsel, since known as Lord Abinger and Sir William Follett, complimented Trevithick on the facility of understanding the case by reference to the model. The writer having carried the surveying chain, was present at the trial at the Bodmin assizes in 1829.

Erskine, who had expressed the opinion favourable to Trevithick's engine more than twenty years before,[148] was in this trial the counsel for the opposing side. The verdict was in favour of Mr. Harvey, or Trevithick's side.

A former chapter[149] speaks of promises to pay certain savings by the use of Trevithick's inventions prior to his leaving for America. The United Mines refused to continue the payment, and on Mrs. Trevithick's application to Mr. Davies Gilbert for advice he kindly wrote to the Williamses, who managed those mines, and received the following reply:—

The opinion of Mr. Williams' elder son, Michael, has been given.[150] Some of the family were quakers. No further money payment for the saving of fuel followed this carefully civil note, until Trevithick, on his return from America, called at Scorrier House in a very threatening attitude on 31st October, 1827, when Mr. Williams, sen., said his reason for not continuing the payment was from his belief that the term of the patent had expired. Then came the following lawyer's letter:—

Such were the recollections of the family solicitor many years after the events had passed. The cylindrical high-pressure steam boiler and engine was really included in the patent of 1802; but frequent detail changes, consequent on size and position and local requirements, were made up to 1811, when a perfected form was arrived at, which is still in use. In principle it was unaltered and not materially different in form, but being used for larger engines, looked different. The inventor saw nothing in this difference, but the public did, and in the absence of the only man who could prove their error refused to pay on the plea of its not being patented. On his return from America he demanded 1000l. from each of the large Cornish mines, as a settlement in full for all benefits derived from the use of the Trevithick high-pressure steam-boiler. He had proved the weakness of the law years before, when three eminent counsel had given opinions on the 1802 patent, one of them believing the patent good, because the principle contained was new; two of them feared that similarity of details might invalidate it:[151] so he determined to apply to the Government for remuneration for benefits that might be called national.

The following petition was drawn up and put into the hands of his old friend Davies Gilbert, then a Member of Parliament:—

"To the Honourable the Commons of the Kingdom of Great Britain and Ireland in Parliament Assembled.

"The Humble Petition of Richard Trevithick, of the Parish of Saint Erth, in the County of Cornwall, Civil Engineer, 27th February, 1828,

"Sheweth:

"That this kingdom is indebted to your petitioner for some of the most important improvements that have been made in the steam-engine, for which your petitioner has not hitherto been remunerated, and for which he has no prospect of being ever remunerated except through the assistance of your Honourable House.

"That the duty performed by Messrs. Boulton and Watt's improved steam-engines in 1798, as appears by a statement made by Davies Gilbert, Esq., and other gentlemen associated for that purpose, averaged only fourteen millions and half (pounds of water lifted 1 foot high by 1 bushel of coals), although a chosen engine of theirs, under the most favourable circumstances, at Herland Mine lifted twenty-seven millions,[152] which was the greatest duty ever performed till your petitioner's improvements were adopted, since which the greatest duty has been sixty-seven millions, being more than double the former duty. That prior to the invention of your petitioner's boiler the most striking defect observable in every steam-engine was in the form of the boiler, which in shape resembled a tilted waggon, the fire applied under it, and the whole surrounded with mason-work. That such shaped boilers were incapable of supporting steam of a high pressure, and did not admit so much of the water to the action of the fire as your petitioner's boiler does, and were also in other respects attended with many disadvantages.

"That your petitioner, who had been for many years employed in making steam-engines on the principle of Boulton and Watt, and had made considerable improvements in their machinery, directed his attention principally to the invention of a boiler which should be free from these disadvantages; and after having devoted much of his time and spent nearly all his property in the attainment of this object, he at length succeeded in inventing and perfecting that which has since been generally adopted throughout the kingdom.

"That your petitioner's invention consists principally in introducing the fire into the midst of the boiler, and in making the boiler of a cylindrical form, which is the form best adapted for sustaining the pressure of high steam.

"That the following very important advantages are derived from this, your petitioner's, invention. This boiler does not require half of the materials, nor does it occupy half the space required for any other boiler. No mason-work is necessary to encircle the boiler. Accidents by fire can never occur, as the fire is entirely surrounded by water, and greater duty can be performed by an engine with this boiler, with less than half the fuel, than has ever been accomplished by any engine without it. These great advantages render this small and portable boiler not only superior to all others used in mining and manufacturing, but likewise is the only one which can be used with success in steam-vessels or steam-engine carriages. 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, to confine the fire by which they were encircled, and it would have been impossible, independent of the great additional bulk and weight, that boilers thus constructed could withstand the rolling of vessels in heavy seas; and notwithstanding every precaution the danger of the fire bursting through the brick and mason work could never be effectually guarded against.

"That had it not been for this, your petitioner's, invention, those vast improvements which have been made in the use of steam could not have taken place, inasmuch as none of the old boilers could have withstood a pressure of above 6 lbs. to the inch, much less a pressure of 60 lbs. to the inch, or even of above 150 lbs. to the inch when necessary.

"That as soon as your petitioner had brought his invention into general use in Cornwall, and had proved to the public its immense utility, he was obliged in 1816 to leave England for South America to superintend extensive silver mines in Peru, from whence he did not return until October last. That at the time of your petitioner's departure the old boilers were falling rapidly into disuse, and when he returned he found they had been generally replaced by those of his invention, and that the saving of coals occasioned thereby during that period amounted in Cornwall alone to above 500,000l.[153]