Pagina-afbeeldingen
PDF
ePub

selves master of the invention, and were determined to anticipate us in our object of securing a patent in London.

In consequence of this report, the experiments which were made with this machine were performed in a hasty manner. The machine itself was complicated with parts which were of no use, and are not worth a description. The only principle which gave it any apparent superiority to the common pump was not stated in the patent specification. By the aid of this principle, however, which we shall presently describe, water was raised in a hasty experiment through leaky tin pipes, apparently by suction or the pressure of the atmosphere alone, forty-two feet from the surface of the fountain to the bottom of the cylinders in which the pistons were worked.

From these experiments, it should seem that some new principle in the laws of hydraulicks was developed; as the simple pressure of the atmosphere can never elevate water to a greater height than thirty-four feet.

But my principal hopes of deriving benefit from this machine, consisted in its property of drawing water from a distance through pipes, ascending from the fountain to the place of delivery on a principle not dissimilar to what is now in practice in England, and for the application of which a lucrative patent was obtained by a Mr. Dalby. I embarked from New York the fifth of May, and arrived in London, after a tedious passage, the fourth of July. I waited on Mr. King, then ambassadour from the United States, to whom I had letters, and was by him favoured with a letter to Mr. Nicholson, an eminent philosopher and chymist, at Soho square. With this gentleman I had several interviews on the subject of my hydraulick machine, and from him received an opinion in writing, stating his unfavourable view of its merits. I likewise made a number of experiments in London, with a different result from what I had seen in Vermont.

In this desperate situation of the adventure, I received a letter from one of the Vermont company, informing that there was a deception in the patent. That by some experiments made subsequent to my departure for London it appeared that no water could be raised by Langdon's invention higher than by the common pump, unless by a perforation in the pipe, which made what the inventor called an air hole; and which by him had been kept a secret, and not mentioned in the patent specification.* This perforation, by admitting air into the pipe, lessened the gravity of the column of water and caused it to rise some feet higher than it could be forced by the simple pressure of the atmosphere. I troubled Mr. Nicholson again with this last principle: he informed me that a similar deception had been practised on the academicans at Paris, but that the trick was discovered by the hissing noise made by the air rushing into the aperture in the pipe.

My next essay was an attempt to improve on the principle last developed, by which a column of water might be raised higher than it could be carried by the simple pressure of the atmosphere, by admitting air into the pipe to assist in its ascent. This I shall briefly sketch, and I hope to make my meaning intelligible without a diagram.

Suppose the simple apparatus of what is commonly called a suction pump, moved by steam or any other power, were placed at the top of a pipe leading sixty feet perpendicular height from the fountain and the air exhausted from the pipe by the operation of its piston. The water would rise in this pipe thirty-three feet and two-thirds nearly, leaving a vacuum from the surface of the water thus elevated in the pipe, to the bottom of the piston. At the height

* This was such a fraud in the inventor, that by every principle of law and reason the patent was void, and no contract founded on it could be valid.

of thirty feet from the fountain I would have a valve in the pipe, opening upwards. Immediately above this, a pipe branching horizontally from the main pipe to what I will call a second pump box, from which the air would be exhausted by the operation of the piston at the top of the main pipe. In the top of the second pump box I would likewise place a small valve opening upwards. This valve should communicate with a piece of cork or other light wood appended to the valve by a rod within the box. The air being exhausted within the machine, the water would rise and flow into the second pump box, and by floating the wood, would lift the valve at the top of the box, the air would rush in, and shutting the valve below, operate by its spring or pressure to force the water into the box at the top of the main pipe.

If the main pipe were continued to a greater perpendicular height from the fountain, suppose ninety feet, by placing a third pump box, branching pipe and valves similar to the second and its apparatus as above described, and an exhaustion made at the top of the pipe, the water would be raised by renovated pressure of the atmosphere ninety feet; and by a succession of similar machinery, to any height short of that in which the pressure of the atmos phere would cease to operate. This invention I proposed to apply to raising water from deep wells, coal mines, &c. and in situations where it was necessary to raise water a great height, but impossible or inconvenient to apply the machinery of a common lifting or forcing pump.

Having completed a tolerable sketch by way of a diagram of this invention, I consulted Mr. Nicholson, and some other gentlemen of mechanical skill, respecting its merits. They all agreed that it was new, ingenious, and might be in some situations useful; but thought that the expense of a patent, which in England is near £120 and the difficulty of obtaining patronage for a new thing,

2

though it might be really useful, ought to deter me from attempting to prosecute my improvement.

I now relinquished all hopes of being able to effect any thing beneficial to my employers or myself by Langdon's machine, or by any possible modification of any of its principles, and in August 1801 was preparing to return to America.

At this juncture, an American introduced himself to me at my lodgings in the Strand, whom I had never before seen. He informed me that he was the inventor of a new and curious machine for grinding corn and other useful purposes, for which he had obtained a patent. That sir William Staines, then mayor of London, was at the head of a company for carrying his patent into effect.-That he had sold one fourth part of his patent for £500 sterling to a gentleman who was a great mechanick, a person of much respectability, a city surveyor, and possessed of a large property-That he, the inventor, had built a number of mills in America, and was fully competent to direct, in every particular, respecting his invention. He produced the counterpart of his assignment of one fourth part of his patent, in which £500 was expressed as the consideration of the deed. I found on inquiry that he had married the daughter of a clergyman, settled in London, and a person of respectable appearance, and I saw no reason to disbelieve any of his statements. This adventurer likewise produced a small model of his machine, which seemed to be the work of considerable ingenuity. At length, after some hesitation and inquiry, I was prevailed on to purchase one fourth of the patent, and was sufficiently punished for my temerity.

The mayor soon took the liberty of seceding from the The rich partner who was prior to me in the purchase of a part of the patent, was not exactly so rich, nor

concern.

quite so respectable as had been represented. The £500 stated to have been paid by him was only a nominal sum to induce others to purchase. The patentee sold out, and I found that no ordinary exertions were necessary to prevent the total failure of the whole scheme. A company of four persons was now formed to build a machine, on a cheap scale, on the Thames, which, it was hoped, would display the principles of the patent, and perform work enough to requite the expense of construction.

In order to become in some measure competent to render assistance in this undertaking I set about investigating the principles on which a machine ought to be built, which would come within the patent. From the writings of Smeaton, Ferguson, the Encyclopædia Britannica, and some other authors who had treated on such branches of mechanical philosophy as were connected with this subject compared with experiments, which had been made with a view to this patent, I was able to develop its principles and recommended such rules as those concerned have been taught by experience to adopt. But I found myslf connected with men who despised science, who could not even comprehend my statements, and who proceeded in spite of my remonstrances to spoil the machine. After suffering no small degree of vexation, fatigue, and anxiety, I induced to attempt to make my pen subsidiary to my support. In the prosecution of this last plan, I published Terrible Tractoration, and a volume of Original Poems, both of which met a favourable reception by the publick, and were recommended by professional criticks.

Those, however, who are best acquainted with me, will do me the justice to believe, that I never should have. written a work calculated to give the tractors favourable notice, had I not fully believed in their efficacy. As conductors of animal electricity, and in principle allied to the Galvanick stimulants, even their modus operandi may b

« VorigeDoorgaan »