AMERICAN MECHANICS' MAGAZINE, Museum, Register, Journal and Gazette. "The most valuable gift which the Hand of Science has ever SIR,-If I understand your correspondent M. S of Lancaster, aright, when he makes his inquiries respecting a Plan for a Pump, it is that of having to supply three adjoining rooms by means of a pump, which must be so constructed, that an individual in any of the rooms shall only pump for himself; or, in other words, that the water pumped up shall only VOL. I. K run out at the spout in his apartment. This, I think, is not a matter of much difficulty; one plan I now send, and have been careful that it shall be as simple as I think the case admits of, and, I believe, perfectly new. If it but furnishes a hint to the ingenious workman, my purpose will be fully answered. Description. Let FG and EE, fig. 1, represent the walls which separate the different apartments; let the shaded circle, HIK, be the cistern, in which three perforations are made where the water is to run from, and let the outermost circle be a ring of metal, to which the spouts are to be affixed in the points AAA: the ring need not be much wider than the diameter of the spouts, and it must nicely fit on the cistern, towards the bottom, as shown at CD, fig. 2, and ought to be ground in the same manner that the plug of a brass cock is; that is, the working surfaces of the cistern and ring must be a portion of a cone. It is then evident that the water will not run out of the cistern but where the spout corresponds to the hole made in it; thus in the position AAA, it is evident the water will issue only from the spout A through the orifice H. Now, using the spout as a handle, turn the ring round into the position B: the orifice, H, will then be closed, and the spouts will be in the position BBB, and the water will issue through the orifice, I. In the same manner, if we move the spout to C, the water will only issue from K; thus each separate individual in the three rooms can turn the water on in his own room, and, at the same time, shut it off from his neighbour's. It will be evident that a stop must be placed to limit the motion of the spout in the arc BC; and by placing a mark on the cistern, we always know when the spout is in its right place; but this will be only necessary at the spout A, as the stop at D and C will of itself tell when the spout is in its right place. Figure 2 is a perspective representation of the pump, as fixed, with the working part, &c.; and as all the handles work in a similar manner, it will be only necessary to show one to explain the three. PQ and RS are the two walls that separate the rooms; ABCD, the cistern of the pump, with its ring, CD, and spout E; FG is the piston rod working through a cross bar fixed at MN, thereby keeping itself always perpendicular; HIKL is one handle, IKL is in one piece (a bent lever,) working on a centre at K; the piece IH is jointed at I and H to the handle, and the projecting joint fixed to the piston rod at H; each handle is fixed in like manner; and, for the sake of the more easily working, the handle, KL (as well as all the others,) may be made to take off near K, and only fixed when wanted to pump. RAILWAYS. There is no single circuinstance so essential to the improvement of a country, as abundant and easy means of internal communication. Part of the price of commodities always consists of the expense of bringing them from the place where they are made or raised to the market. In improved districts this amounts, in general, only to a small percentage upon the first cost; but in rude and backward districts, unprovided with tolerable roads, it often enhances the cost of the article to three or four, or even ten times the original amount, and of course either greatly lessens or entirely precludes their use. Coal, for instance, is not found within less than a hundred miles of London; and had some more economical mode of conveyance than carting not been found out, this article which is sold at 40s. a ton in the metropolis, would have cost six pounds-a price which would have been nearly equivalent to a prohibition against the use of this species of fuel. Such are the vast facilities which navigation affords for the transportation of commodities, that the coal of Gloucestershire can be sent by sea at a cheaper rate to Jamaica, than it could be sent by land in carts to London. 147 Railways are a much more recent invention than canals; and for par、 ticular purposes, such as the conveyance of coal, stone, or other heavy commodities, down a short inclined plane sloping at an angle of three or four degrees they are decidedly superior. As a means of general communication, they are cheaper in the first outlay than canals, more commodious in some respects, and adapted to a greater variety of situa tions; but so long as horse-power was the only power employed, it may be doubted whether the balance of advantage was not in favour of canals. We are quite satisfied, however, that the introduction of the locomotive steam power has given a decided superiority to railways. Indeed we are convinced, and we hope, by-and-bye, to convey some share of the conviction to the minds of our readers, that the general use of railways and steamcarriages, for all kinds of internal communication, opens prospects of a'most boundless improvement, and is destined, perhaps, to work a greater change on the state of civil society, than even the grand discovery of navigation. ་ The value of the railway as a medium of commercial communication, has not escaped the sagacity of Dr. Young. In his lectures on natural philosophy he says: It is possible that roads paved with iron may hereafter be employed for the purpose of expeditious travelling, since there is scarcely any resistance to be overcome except that of the air; and such roads will allow the velocity to be increased almost without limit."" In early times the roads were mere Iron railways are of two descripfoot-tracks, and goods were univer- tions. The flat rail or tram road sally carried on the backs of horses. Consists of cast iron plates, about To these succeeded gravelled roads three feet long, four inches broad, and for wheel carriages, and the latter an half an inch or an inch thick, were followed by canals. A horse put into a wheeled carriage wil draw, upon a well-made road, as much as four horses would carry on their backs; but when employed in tracking a boat on a canal, he will perform as much work as thirty horses in carts, or as a hundred and twenty pack-horses. *From "The Scotsman." with a flaunch or turned-up edge on the inside, to guide the wheels of the carriage. These plates rest at each end on stone sleepers, of three or four hundred weight, sunk into the earth, and they are joined into each other, so as to form a continuous horizontal pathway. They are of course double, and the distance between the opposite rails is from three to four feet and a half, according to the breadth of the car or wagon to be employed. The edge rail, which is found to be superior to the tram rail, is made either of wrought or cast iron. If the latter is used the rails are about three feet long, three or four inches broad, and from one to two inches thick and they are joined at their ends by cast metal sockets attached to the sleepers. The upper edge of the rail is generally made with a convex surface, to which the wheel of the car is adapted by a groove made somewhat wider. When wrought iron is used (which is found to be equally cheap with cast metal, and greatly preferable in many respects), the bars are made of a smaller size, of a wedge shape, and twelve or eighteen feet long but they are supported by sleepers at the distance of every three feet. The wagons generally used run upon four wheels, of from two to three feet diameter, and carry from 20 to 50 cwt. Four or five of them are Weight of the load drawn Weight of the load and wagon in pounds Lanely tram road Penryn edge rail 4,602. Cheltenham tram road. New branch of ditto, dusty Edge railways, near Newcastle. 17,773 8,850 9,000 13,050 15,500 18,300 21,900 25,500 This table shows the great supe- the mark." (Memorial, p. 12.) We riority of the edge rail. The engineer speak here of railways of the ordiobserves too, that the vehicles were nary kind for the transportation of made in a very rude manner, and goods; but it is probable, that one desthat were more care employed in their tined to serve the purpose of a great construction, the load might be much national thoroughfare, for vehicles of increased. Railways are generally all kinds, quick and slow, would cost made double, one for going, and the at least twice as much. Even in this other for returning. The breadth of case, however, the original outlay ground required for a single railway would certainly not amount to more is from nine to twelve feet; for a than a half or a third of what would double one, from nineteen to twenty- be required for a canal of such a magfive. The expense of a double road, nitude as to afford the same amount including the price of the ground, of commercial accommodation. The may be estimated generally at from Union Canal has cost altogether about 3000l. to 5000l. per mile, or from one- 12,000l. per mile; the Forth and half to one-third of the expense of a Clyde, if executed at this day, would canal. Mr. Stevenson says-"The cost twice as much; the Caledonian first expense of a canal will be found Canal, if we exclude the locks, and to be double, if not treble, the expense reckon only what has been cut, will of a railway: such are the difficulties ultimately cost about 50,000 per of passing through a well-cultivated mile. Even deducting what has been country, and especially of procuring expended on the locks, and on the a sufficient supply of water in manu- harbours at its extremities, the exfacturing districts, that four times the pense will be nearly 40,000l. per expense will in most cases be nearer mile. ELEMENTS OF AERIAL NAVIGATION. 149 A railway from Glasgow to Ber- snow would produce no obstruction; wick, 125 miles long, projected in it could be carried over uneven 1810, was surveyed by Mr. Telford, ground, and over small hollows or and estimated to cost 365.7001., or ravines, without cutting, embanking, 2926 per mile. The estimated ex- or casting bridges, by merely lengthpense of a railway from Birmingham ening or shortening the pillars; the to Liverpool, distance 104 miles, lateral friction, from the want of persurveyed within these few months, is fect parallelism in the two opposite 350,000 or 3365 per mile That rails of the ordinary railway is avoidof one from the Crawford Canal to ed; and in many cases the rail might the Peak Forest Canal, in Derby- even be carried along the side of a shire, 32 miles long, is 150,000/ or common cart-road, with a very small 4700 per mile. A recent Carlisle additional expense. Mr. Palmer, Paper states, that the expense of a who made some trials with a portion railway between that city and New- of railway formed in this manner, castle was estimated at 252,000., or states, that the effect produced by 4000 per mile; and that of a canal the draught of a single horse was at 888,000l., or 14,000l. per mile. A nearly double of that produced on railway projected to run from Man- the common railway, or 45,000 chester to Liverpool, 33 miles, has pounds, including the vehicle. There been estimated to cost 400,000l., is nothing in the nature of this mawhich is no less than 13,000 per chine to render steam power inapmile; but this includes a large amount plicable to it. for warehouses and locomotive engines. Lastly, a railway from Dalkeith to Edinburgh, including a branch to Fisherrow Harbour, nine miles and a quarter long altogether, will cost, according to the recent estimare of Mr. John Grieve, 36,862, or 39831. per mile, including the expense of five locomotive and one stationary steam engine. (To be continued.) ELEMENTS OF AERIAL NAVIGATION. It is a singular circumstance in the history of the arts, that an invention at its first appearance is frequently pursued with the greatest eagerness, and yet will afterwards be wholly neglected for years, until some happy improvement fixes it permanently on the public attention. Many will remember the great zeal excited by the subject of aerial navigation among scientific men, and the astonishing subsequent neglect of an art so important, until the late revival of the subject by Sir George Cayley and other eminent philosophers. The following statement of every thing important which has been suggested on this point, with some new views, is offered for the purpose of facilitating farther inquiries. Mr. Palmer, the engineer already mentioned, has proposed a new and ingenious species of railway, which deserves notice. It consists of a single rail, or continuous rod, of the usual form, but raised about three feet from the surface of the ground, and supported by cast metal pillars every ten feet. Two wheels with grooved edges, and 24 or 30 inches diameter, run, the one before the other, upon this railway; and from the iron frame to which they are attached by their axles, two chests or receptacles made of iron are suspeded by stiff rods, exactly like panniers from the back of a horse. The 1. The balloon being inflated with chests hang very near to the surface gas, descends by letting out a of the ground; the load which is in portion of it, and ascends again by those chests being so low that the throwing out ballast. To this mecentre of gravity is always beneath thod it is a radical objection, that the level of the rail, the machine, the means of alternate ascent and unless very unequally loaded, has no descent are very soon exhausted. tendency to overset. The principal 2. The air in the balloon being advantages of this contrivance are expanded by heat, the vertical motion the following:-A moderate fall of is produced by increasing or dimi Vertical Motion. |