« PredošláPokračovať »
OTHER INVENTIONS. entitled to receive. In his resentment he says, that “not a tittle will he disclose of two other inventions of his until he has justice done him on account of his rowing engine.” The first of these
a gin of fourteen inches square, portable by one man, and by which one man may lift the largest cannon into her carriage.” The second contrivance was a method whereby he could fight any ship,“ using charge and discharge as often as six do now, and to as much purpose, without any manner of incommodation, more than by the common way, so that one half of the men need not be exposed that now are, and the rest may be kept as a reserve for boarding ; the benefit of this I leave to the ingenious sailor.”+
* Navigation Improved, or the art of rowing ships, of all rates, in calms, with a more easy, swift, and steady motion than oars can, by Tho. Savery, gent. London, 1693. `In 1693, a M. Duquet made several experiments at Marseilles, at the expense of the King of France, to navigate a vessel by revolving paddles, or wheels, instead of oars. The results of these trials were very satisfactory, and strongly directed the attention of philosophers, as well as mechanics, to the practicability of this application of water-wheels. Machines approu. vées, tome i. p. 173.
+ Sir Isaac Newton, in a report (dated Leicesterfield, January 27, 1718) which he made to the government, on the practicability of an invention for measuring a ship's way at sea, mentions Savery as the inventor of this machine, and notices another of his contrivances. “Mr. Savery, who invented the raising of water by fire, told nie, about six years ago, that he had invented an instrument to measure the distance sailed, and, by his description, that instrument was much like this, (the one submitted for his opinion,) the seawater driving round the lowest and swiftest
wheel thereof, and that wheel driving round other wheels, the highest and lowest of which turned about an index to show the length of the way sailed."
Savery complained of one of his inventions being neglected, from its ressmbling a mechanism with which he was unacquainted; but Savery's one, which is now mentioned, was itself only a copy from another described by Bourne, in his
101 The enthusiasm of the projector was softened in Captain Savery by the experience of a practical mechanic; and he early appears to have acquired that personal consideration, which usually follows a man of genius and enterprise, when his habits are those of a man of business.
At the first announcement of his machine for raising water, he had so matured his ideas, and was so well versed in the nature” and power of the motive agent, that his masterly combi: nation has left but minor objects for improve, ment to succeeding engineers. His mode also of introducing his invention to the notice of the public was totally different from that which had been followed by former projectors. They enve. loped every thing in mystery, and endeavoured to attract attention by exaggerated statements of power or economy. His first step was to explain to every one the principles, as well as construction, of his apparatus: he showed why it was a cheaper power than that of horses or men, and inventions, as produced by a Humphrey Cole. De Saumarez complains, in his turn, of Savery's scheme being remembered by Sir Isaac only to get rid of his claim. The picture he draws of his pursuits and projects is an excellent likeness of a large, but harmless class--can it be named ?-of simple schem
“ He was the son of De Saumarez, chaplain to Charles II. ; although he was bred in Holland to learn consmerce, he never applied himself to any trade or profession, but in an easy and quiet enjoyment of his small estate, in the island of Guernsey, he took his diversion in the experimental part of mathematics, his genius or inclination being that way for machines and inyentions, wherein he spent about twenty-two years last past, confining himself to a retired sort of life, within his little ela. boratory; and of late he fixed his projects upon a particular invention, towards the improvement of navigation, which he could not bring forth to effect in the island for wantof able workmen; but he came to London on purpose, and he hath actually began, and hopes, with the blessing of God, to bring it to soñae perfection." Memorial, p. 4.
he invited practical men to judge for themselves of the value of his assertions and statements, by an inspection of the machine itself in operation.
The influence of the court was, at this period, considered to be essential to the success of any speculation which required the aid of a monopoly. The profits might be diminished or overthrown by the obstacles which avarice and intrigue could then interpose in that quarter to its further progress; and, from this circumstance, considerable importance was attached to having the countenance of those in power to any project in which the pecuniary risk required to be extensive; and Captain Savery might be said to be conforming to an almost common practice, when he exbibited a working model of his fire-engine before King William, at Hampton-court. That monarch, who himself had a mechanical turn, was so pleased with its ingenious construction and effective action, that he took a warm interest in its success, and permitted its author to inscribe to him the account which he published of his contrivance, under the title of “The Miner's Friend."
The great fame of the Royal Society, then adorned by the presidency of Sir Isaac Newton, made its opinion to be listened to with profound respect in matters of science and mechanics. To that body also Captain Savery carried his invention, and in their transactions for that year, is a record of his successful experiment, made in their a partment, and a view and description of the machine forms the subject of an engraving in their anuual volume.
As every form in which it appeared during the lifetime of its inventor is interesting, as showing the steps of its improvement, the model Savery
ROYAL SOCIETY'S MODEL. 109 exhibited before the Royal Society, in 1699,* will require a brief description.
In the engraving marked Savery, the pipe, k, conducts steam from the boiler (but which, not to crowd the figure, is omitted) into two receivers; a pipe, i, branching to each of these vessels, is inserted into their bottom, having valves at e, e, d, f, opening upwards, and preventing, by their action, the return of any water which may have been forced through them. A pipe, h, proceeding from the cistern, also branches to both receivers, and is inserted into the top of each. Valves are placed at c, c, by which a communication may be opened, or shut off with the boiler, and each receiver, alternately, accordingly as they may be adjusted; one being open when the other is closed.
Steam from the boiler being permitted to flow into either of the receivers, the water which that receiver contains is forced by the steam from the boiler, pressing upon its surface, up one of the branches of the pipe, i, and when the vessel is, by this means, emplied of the water which it contained, and filled with steam, by turning the cock, or valve, c, the communication with the boiler is shut off; cold water is then poured over its surface; this, cooling the apparatus, condenses the steam which it encloses, and, by this means, a vacuum is formed within the receiver, and the pressure of the atmosphere forces the water of the cistern up the pipe, h, into the empty vessel. At the instant in which the steam was shut out from the one receiver, by turning the other valve it was permitted to flow into the opposite one, and it forces the water which it contains up the pipe, i, during the time that the condensation is
* Phil. Transactions, vol. xxi. p. 228.
MINER'S FRIEND. heing produced in the other vessel. When the steam has expelled all the water, and completely fills this receiver, cold water is thrown on the outside of the vessel; the steam within it is condensed also, and the pressure of the atmosphere acts again to raise the water of the cistern up the pipe, h, into the second re. ceiver, in which a vacuum has thus been produced. The cock, c, by which the communication was interrupted, when the first receiver was filled with steam, is now turned the contrary way; the steam again flows into that vessel, which has been in the interval filled with water, and begins to force the fluid upwards, as before; and this alternate emptying and refilling of the cylinders may be prolonged at pleasure.
Such was the first form of Savery's celebrated engine for raising water by fire: before, however, he offered it as a machine admirably adapted for the purpose of raising water from mines, many essential parts were to be added, and all were to be constructed to offer a precise and determinate action.
These appear to have been supplied before 1702;* at that time he dates his address to the “Gentlemen Adventurers in the Mines in England,” and gives a detailed account of the construction and action of his machine, a concise view of some of its advantages, and enumerates the purposes to which it
* The Miner's Friend; or a description of an engine for raising wa ser by fire, with an answer to the objections against it. By Thomas Savery, Gent. London, 1702. Reprinted, soon after its publication, in a quarto form, along with Decaus's book. "A new and rare invention of water-works, teaching how to raise water higher than the spring, as also a description of Captain Savery's engine for raising vast quantities of water by fire.” London, 1704. The experiments on steam are omitted in this reprint also of Decaus. The engrav. ing prefixed to the Miner's Friend is given in this volume.