Chap. 8.] Newsham's Engines. After referring to a number of machines erected by him in London and its vicinity, Mr. Fowke concludes with a table of prices of fire-engines, the smallest being £14 and the largest £60. Newsham's circular is obviously designed to counteract the effect of Fowke's. 66 RICHARD NEWSHAM, of Cloth Fair, London, engineer, makes the most useful, substantial, and convenient engines for quenching fires, which carries continual streams with great force. He hath play'd several of them before his majesty, and the nobility, at St. James's, with so general an approbation, that the largest was at the same time ordered for the use of that royal palace. And as a further encouragement (to prevent others from making the same sort, or any imitation thereof) his majesty has since been graciously pleas'd to grant him his second letters patent, for the better securing his property in this, and several other inventions for raising water from any depth, to any height required. soever. "The largest engine will go through a passage about three foot wide, in complete working order, without taking off or putting on any thing: and may be worked with ten men in the said passage. One man can quickly and with ease, move the largest size about, in the compass it stands in: and is to be play'd without rocking, upon any uneven ground, with hands and feet, or hands only, which cannot be parallel'd by any other sort whatThere is conveniency for above twenty men to apply their full strength, and yet reserve both ends of the cistern clear from incumbrance, that others at the same time may be pouring in water, which drains through large copper strainers. The staves that are fixed through the leavers, along the sides of the engine, for the men to work by, though very light, as alternate motions with quick returns require; yet will not spring and lose time the least: but the staves of such engines as are wrought at the ends of the cistern, will spring or break, if they be of such a length as is necessary for a large engine, when a considerable power is apply'd and cannot be fix'd fast, because they must at all times be taken out before The playing two streams at once, that engine can go through a passage. do neither issue a greater quantity of water, nor is it new, or so useful, there having been of the like sort at the steel-yard, and other places, thirty or forty years; and the water being divided, the distance and force are accordingly lessen'd thereby. "Those who pretend to make the forcers work in the barrels, with a perpendicular stroke, without rack, wheels, chains, crank, pully, or the like, by any kind of contrived leavers, or circular motion whatsoever, with less friction, than if guided and work'd by wheel and chains, (which of all methods is the best,) do only discover their ignorance; they may as reasonably argue, that a great weight can be dragg'd upon a sledge, with as little strength, as if drawn upon wheels. "As to the treddles, on which the men work with their feet, there is no method so powerful, with the like velocity or quickness, and more natural and safe for the men. Great attempts have been made to exceed, but none yet could equal this sort; the fifth size of which hath play'd above the grasshopper upon the Royal Exchange; which is upwards of fifty-five presence of many thousand spectators. yards high, and this in the "Those with suction feed themselves with water from a canal, pond, well, &c. or out of their own cisterns, by the turn of a cock, without interrupting the stream. They are far less liable to disorder, much more durable in all their parts, than any extant, and play off large quantities of water to a great distance, either from the engine, or a leather pipe, or pipes of any length requir'd; (the screws all fitting each other.) This the cumbersome squirting engines, which take up four times more room, can 334 Newsham's Engine. [Book III. not perform; neither do they throw one fourth part of their water on the fire, at the like distances, but lose it by the way; nor can they use leather pipe with them to much advantage, whatever necessity there may be for The five large sizes go upon wheels, well box'd with brass, fitted to strong iron axles, and the other is to be carried like a chair." it. No. 150 is a vertical section of the pumps in Newsham's engine, with the air vessel between them, and showing also the sectors and chains by which motion is transmitted from the levers to the piston rods, and the latter preserved in a perpendicular position. The chains are similar to watch chains in their construction, and the length of each is equal to the arc of one of the sectors. Four are used, two to each sector. Their mode of operation is in this manner: One end of a chain is fastened to the top of a piston rod, by a bolt and nut as represented, and the other end riveted to the lower extremity of the sector; so that when the latter is turned down by depressing the lever, it necessarily draws, by this chain, the piston down with it. Another chain is fastened in the same manner to the lower part of the piston rod, (that is above the cyNo. 150. Section of Newsham's Engine. linder,) and the upper extremity of the sector, and hence when the lever is elevated, this chain raises the piston with it. He probably derived the idea of thus working them from Newcomen's mode of working pumps by the atmospheric steam-engine. The round opening below the valves in the above figure, is where the suction pipe is continued to the hose, shown at one end of the cistern in the next figure. No. 151. Newsham's Fire-Engine, A. D. 1740. Chap. 8.] Modern English Engines. 335 No. 151 is an external view of one of Newsham's engines at the time of his death, as drawn by Mr. Labelye, the engineer of Westminster bridge, and inserted by Desaguliers in the second volume of his Philosophy, in 1744. Its general appearance is far inferior to modern ones, but the essential parts-the pumps-were equal to those now used. The strong iron shaft by which the pistons were raised and depressed was continued along the top of the cistern, and to it the levers were secured as at present; but in addition to the levers, sectors, like those that moved the pistons, were also fastened to it-portions of two of these are shown in the cut, and there were two others near the upright case: to their upper parts, two long strips of plank, or treddles, were suspended by short chains, and on these planks, six men, who stood upon the cistern and held by the hand rails, alternately threw their weight; first on the treddle on one side of the carriage, and then on the other, and thus aided the firemen at the levers in working the engine. The box or trough, with a grate within it, at the end of the cistern, was for the purpose of emptying buckets of water to supply the pumps, when the suction pipe (figured below it) was not used. The small flap on the end of the upright case covered printed directions how to use and keep the engine in order. If the section, No. 150, be compared with English engines in previous use, one of which is figured at No. 149, it will be seen at a glance how great were the improvements that Newsham introduced. Independently of the three most original of his contributions-the sectors and chainstreddles-and working the pumps with long staves at the sides of the carriage instead of short ones at the ends-the whole machine was improved more or less in every part. To keep the cistern and levers as low as possible, the carriage was placed on bent axles. He introduced and improved the three-way cock, and the goose-neck was perfected in his hands; the elbows being jointed to each other by very fine screws. saguliers thought that no part of the engine could be altered for the betA writer in the London Magazine for 1752, (page 395,) says that Newsham in these machines gave 66 a nobler present to his country than if he had added provinces to Great Britain." Their merits were generally acknowledged: he received orders for them from various parts of Europe, and it will be seen in a subsequent part of this chapter that those first used in this city were made by him. ter. De The celebrity his engines acquired had a blighting effect on other manufacturers-like Aaron's rod swallowing up those of his competitors. His engines were purchased for the use of the parishes throughout the country generally, and also by the various insurance companies, which, unlike ours, are at the sole expense of extinguishing fires, and of providing the means to effect it. Every insurance company in English cities keeps in its pay a number of firemen to take charge of and work its own engines. Two horses are attached to each engine to draw it to and from fires. The height of the jet from Newsham's engines was about fifty feet. He mentions in his circular having thrown it to an elevation of fifty-five yards, but he was certainly mistaken. Several improvements have been made in English fire-engines since Newsham's time, but they are chiefly confined to the carriage, and to details and arrangements of the various parts. Treddles are dispensed with, and the carriages are made longer, so that a greater number of men can be employed in working them. They resemble American engines so closely, that a separate figure of a modern English engine is unnecessary. The reader is therefore referred to No. 154. Others on the principle of the semi-rotary pump, (No. 140,) are also used to a limited extent in London. 336 Modern French Engine. [Book III. The following figure of a modern French fire-engine is from the Manuel du Fondeur; Paris, 1829. It consists of two cylinders and an air vessel arranged in the usual way. One of the pumps, and half of the air chamber, is shown in section. The cistern is more elevated than in English or American engines, and from the consequent height of the levers would seem more inconvenient to be worked. The suction pipe is of copper with folding joints, and a perforated hollow ball at the extremity to prevent dirt or gravel from entering with the water. A short leathern tube connects this pipe with the suction cock. This engine is worked at the ends of the carriage, and the piston rods are connected to the lever by slings, and made to rise and fall in a perpendicular position by radius bars jointed to the upper ends of the latter, and to permanent pieces that project from the frame that supports the fulcrum. The elevation of the jet depends upon the pressure to which the air in the air chamber is subjected; the elasticity or spring of that fluid being inversely as the space it is made to occupy. Before an engine is set to work the interior of the chamber, like that of all empty vessels, (to use a vulgar solecism,) is filled with common air, of that degree of density in which it appears near the earth's surface; but when the pumps are set to work, the water forced by them into the chamber crowds the air into the dome or upper part of that vessel, whence there is no passage for its escape; and, as the liquid accumulates, the air is condensed more and more, until, by its reaction on the surface of the water, it drives the latter through the jet or hose pipe, and with a force exactly proportioned to the degree of its compressure. Thus if the volume of air in the chamber be compressed into half its bulk, the jet would rise to about 32 or 33 feet, (if not retarded by friction, angles or other imperfections in the pipe;) and if it were made to occupy one third of its former space, its spring would be three times greater than common air, and would force the jet to an elevation of about 64 or 66 feet; and so on. A tabular statement, similar to Chap. 8.] Modes of Working Fire-Engines, 337 the following, exhibiting the relation between the height of a jet and the air's compressure, has long been published. It is, however, of little use to practical men. We doubt if a column of water of the size of those thrown by ordinary engines could be raised by any means, two hundred feet above the orifice of the pipe whence it issued: the resistance of the atmosphere would disperse it before it could reach that elevation. Great as are the advantages derived from air chambers, some attention to them is required in order to secure at all times the benefit they are designed to impart. When neglected (and we believe few parts of an engine exercise the attention of firemen less) they often become actually injurious, for when no advantage is derived from the elasticity of the confined air, the water is impeded in its progress by passing through them. Upon the trial of engines it sometimes occurs that the water is thrown higher at their first working than after they have been a few minutes in use, and this notwithstanding all the efforts of the firemen to make the jet reach the first elevation. This result has sometimes been attributed to fatigue in the men to obstacles in the pipes-to grit or sand under the valves, &c. whereas in fact it was often due to the air vessel alone; i. e. to the escape of air from it. This escape may be occasioned by minute leaks in the chamber, but when no such imperfections exist the air frequently makes its exit, and its place becomes occupied by the liquid. Whenever air is subjected to great pressures in contact with water, it is quickly absorbed by the latter, and in this way it is that it often disappears from the air chambers of fire-engines, and also from those of pressure-engines, Heron's fountain, water rams, &c. When a long suction hose is attached to an engine and the latter worked at a moderate velocity, a sufficient supply of air to replace that taken up by the water, commonly enters, unknown to the firemen, through the seams and joints; but when one engine is fed by another pouring water into its cistern, there is little chance for the requisite supply of air, unless a minute opening were left in the cap that screws over the orifice of the suction pipe, at one end of the engine. The suction cocks of some engines diminish their useful effect in consequence of the holes through the plugs being smaller than other passages for the water. The great desideratum in modern fire-engines is an improved mode of working them. At page 72 we remarked that experimental researches. have shown the useful effect of a man working a pump, in the ordinary way with a lever, to be fifty per cent less than when he turns a crank; and that when his strength is applied as in the act of rowing, the effect is nearly one hundred and fifty per cent more than in moving a pump lever. This is sufficient to induce efforts to supersede the present mode of working the pumps of fire-engines, and particularly so, as the labor is so se |