DESCRIPTION OF A STEAM ENGINE, INTENDED TO GIVE MOTION TO WATER-WHEELS, IN PLACES WHERE THERE IS NO FALL, AND BUT A VERY SMALL STREAM OR SPRING. BY JOHN NANCARROW." A, (Figure 1,) the receiver, which may be made either of wood or iron. B, B, B, B, B, wooden or castiron pipes, for conveying the water to the receiver, and thence to the penstock. C, the penstock or cistern. E, the boiler, which may be either iron or copper. F, the hot well for supplying the boiler with water. G, G, two cisterns under the level of the water, in which the small bores B, B, and the condenser are contained. H, H, H, the surface of the water with which the steam-engine and the water-wheel are supplied. a, a, the steam-pipe, through which the steam is conveyed from the boiler to the receiver. b, the feeding-pipe, for supplying the boiler with hot water. c, c, c, c, c, the condensing apparatus. d, d, the pipe which conveys the hot water from the condenser to the hot well. e, e, i, valves for admitting and excluding the water. ff, the injection-pipe, and g the injection-cock. h, the condenser. It does not appear necessary to say any thing here on the manner in which this machine performs its operations without manual assistance, as the method of opening the cocks, by which the steam is admitted into the receiver, and condensed, has been already well described by several writers. But it will be necessary to remark, that the receiver, penstock, and all the pipes, must be previously filled before any water can be delivered on the wheel; and when the steam in the boiler has acquired a sufficient strength, the valve at i is opened, and the steam immediately rushes from the boiler at E into the receiver A; the water descends through the tubes A and B, and ascends through the valve k, and the other pipe or tube B, into the penstock C. This part of the operation being performed, and the valve i shut, that at l is suddenly opened, through which the steam rushes down the condensing-pipe c, and in its passage meets with a jet of cold water from the injection-cock g, by which it is condensed. A vacuum being made by this means in the receiver, the water is driven up to fill it a second time through the valves e, e, by the pressure of the external air, when the steam-valve at i is again opened, and the operation repeated for any length of time the machine is required to work. There are many advantages which a steam-engine on this construction possesses beyond any thing of the kind hitherto invented; a few of which I shall beg leave to enumerate. 1. It is subject to little or no friction. 2. It may be erected at a small expense when compared with any other sort of steam-engine. 3. It has every advantage which may be attributed to Boulton and Watt's engines, by condensing out of the receiver, either in the penstock or at the level of the water. * From the Transactions of the American Philosophical Society. 4. Another very great advantage is, that the water in the upper part of the pipe adjoining the receiver acquires a heat, by its being in frequent contact with the steam, very nearly equal to that of boiling water; hence the receiver is always kept uniformly hot, as in the case of Boulton and Watt's engines. 5. A very small stream of water is sufficient to supply this engine, (even where there is no fall,) for all the water raised by it is returned into the reservoir H, H, H. From the foregoing reasons it manifestly appears, that no kind of In steam-engine is so well adapted to give rotatory motion to machinery of every kind as this. Its form is simple, and the materials of which it is composed are cheap; the power is more than equal to any other machine of the kind, because there is no deduction to be made for friction, except on account of turning the cocks, which is but trifling. Its great utility is therefore evident in supplying water for every kind of work performed by a waterwheel, such as grist-mills, saw-mills, blast-furnaces, forges, &c. Description. AN IMPROVED DRAWBACK LOCK FOR HOUSE-DOORS. FIG. 2 is an improved Drawback Lock for house-doors, &c. damp weather, it is well known that the air drawing through the lock rusts the head or bevel of the bolt, by which means it requires great force to shut the door, and occasions a disagreeable noise, besides shaking the building. Owing to the difficulty thence arising in shutting the door on the latch, houses are often exposed to robbery by the door being left unlatched, when it is supposed to be fast. In this improved lock, these inconveniences are removed, as it allows the bolt to shoot into the staple immediately when the door closes, but not before; and the reliever works so very easy, that the door is made fast with one twenty-fourth part of the force required with locks upon the common construction. Fig. 2. A, is the new iron latch here affixed to an old common drawback house lock. B, an iron pin at one end of the latch, on which pin it is moveable. C, a projecting part of the latch, which, when the common spring bolt D of the lock is drawn back, in the usual manner, is forced into the nick on its higher part at E, by the spring F, underneath the latch. ON THE LOSS OF POWER THE To the Editors of the GLASGOW MECHANICS' MAGAZINE. GENTLEMEN,-The following observations, on the loss of power occasioned by the use of a crank, lead to a result different from any that I The bolt D then remains within the lock, until, on closing the door, the reliever, G, gently presses on the lock-box, fixed in the common way on the door cheek; which pressure draws the projecting part C out of the nick E, and permits the end of the bolt D, by the force of the spring G, to slide into the lock-box, and fasten the door. ARISING FROM THE USE OF have seen; which, therefore, how- Let a crank, in its revolution, describe the circle A, C, L, (see fig. 7,) and let the connecting rod move in a vertical line; it is obvious, when the crank is in the position C, that the whole power is exerted in turning the machinery; but in any other position the power is applied at a mechanical disadvantage, and in the vertical points, A and B, no power is communicated. In determining the loss of power, for the sake of simplicity, an infinite number of cranks may be supposed to act around the circumference A, C, B; and it is obvious that, while the friction and atmospheric resistance are the same, there will be exactly the same loss of power, whatever be the number of cranks, provided the motion be uniform in every case. But the same result will evidently be obtained, if, instead of cranks, a number of equal weights be attached at every point in the arc A, C, B, exerting a power equal to the cranks. Now, the effect produced by any one of these weights, acting at any point P, is proportional to P, K, its distance from the vertical line A, B; and hence the effect produced by all the weights will be the same as if they acted in the point G, the centre of gravity of the arc A, C, B. But if they acted at C, instead of G, the circular motion continuing the same, their effect would be increased in the ratio of O, G, to O, C. Now, O, G, is about two-thirds of O, C; hence the whole power employed is to the efficient power as 3 to 2, or about one-third of the power is rendered ineffective by employing a crank. When only one crank is used, there is another obvious disadvantage attending it—the irregularity of the motion. This irregularity occasions a farther loss of power, as every machine must have a certain determinate motion to produce the greatest effect; and, therefore, any irregularity of motion must cause a diminution of effect. When a fly-wheel is employed to produce a more uniform motion, power is also lost in overcoming the friction and resistance of the fly. The momentum which the fly-wheel loses by resistance and friction must be again restored to it by the machinery, when the crank is acting in its most favourable position. If the power could constantly be communicated at the point C, the effect would be increased one-half. The following contrivance appears to accomplish this object: A, B, C, and D, E, F, are two semicircular arcs, whose centres lye in the axis of the wheel E, D, F, fig. 3, and are both provided with the same number of teeth. In fig. 4, another view is given, perpendicular to the former. In fig. 5, L, B, is a lever, and O, T, the point about which it moves. A, C, and D, F, are two circular arcs, having their centres in T, and of the same length with the semicircular arcs C, T, K, H, G, F, and are also furnished with the same number of teeth. When the machine is in the position represented in fig. 5, and the wheel K, T, C, moves in the direction K, T, the interior teeth K, T, C, act upon the teeth A, B, C; and, after a half revolution of the wheel, the machine will be in the position shown in fig. 6. The interior teeth having now passed the teeth A', B', C', the exterior teeth A', G', D', will now act upon the teeth of the larger arc D', E', F'; and, after another half revolution of the wheel, the machine will have regained its former position in fig. 5. The same motion will continue during the successive revolutions of the wheel. If the lever be supposed to act, the same motion will take place. Since the motion is communicated at C, and F,-points in the line of centres T, O, F,-no power is THE most distinctive mark of the present age, and that which will point it out to after ages above even the splendour of its literature, and the wonders of its scientific discoveries, is that thirst for knowledge which pervades the working classes of the people, and the enthusiasm with which the rich and the wealthy lend their aid in enabling them to satisfy their praise-worthy desire. Not many years ago, the great majority of the people were utterly regardless of any thing more than merely the rudiments of education. There were no doubt exceptions, great and glorious exceptions, to this; but take the people of Great Britain altogether, there seemed very little desire among them to acquire any other knowledge. On the other hand, there seemed a desire on the part of the wealthy and the learned to prevent their ever acquiring knowledge, or even a desire for it; and men, otherwise good and valuable members of society, resisted, with all their talent and influence, any attempt to instruct or improve the poorer portion of their brethren. Times, however, have most happily changed. A noble desire pervades the breasts of the poorest of our citizens to acquire useful knowledge; and a praise-worthy spirit is every where abroad among those whom providence has been pleased to bless with a greater portion of wealth, to aid them in their honest desire. We are extremely happy to see this pamphlet of Mr. Brougham's (which was originally published in the pages of the Edinburgh Review) now given to the world separately. The wisdom and philanthropy which its views exhibit, the powerful manner in which it advocates the cause of popular education, and the excellence of the many plans it developes and explains for the furtherance of this great object, entitle it to be universally read; and great as is the circulation of the Edinburgh Review, it is much too limited for such a pamphlet as the pre sent. We sincerely trust that it will not be uninfluential, but that it will have the effect of persuading numbers of the working classes to join their brethren in their attempts to obtain the greatest of all human blessings-knowledge and instruction; and that it will excite * Practical Observations on the Education of the People. Addressed to the Working Classes and their Employers. By Henry Brougham, Esq. M. P. F. R. S. many rich men to co-operate with those who are already lending their steady support to the promotion of so useful an object. The example of such a man as Mr. Brougham must be of incalculable benefit to the design; for what can more excite any man to lend his assistance, than seeing one so famed as he labouring in the cause. Mr. Brougham has probably the most powerful mind of any man now alive. At the bar he is decidedly without a rival; and in the senate-house, who can stand before the thunder of his voice or the lightning of his eye? Mr. Scarlet, with all his legal learning, is but as a child in the hands of Mr. Brougham, when they are opposed to each other in one of the courts; and exquisitely keen and rapid as are the shafts of Mr. Canning's wit, and brilliant as are the flashes and corruscations of his genius, they are perfectly powerless in their effects on Mr. Brougham. Mr. Canning is decidedly a man of genius, and his eloquence must always please and delight his hearers; but Mr. Brougham, whether he pleases or not, must always convince-always overcome. If there ever was a man who possessed the greatest of all the qualifications an orator can possess-power, irresistible, overwhelming power-it is Mr. Brougham: and although as a lawyer and statesman, an orator and a philosopher, his name will descend to posterity, one of the brightest gems in the diadem which an after people will place on his head will undoubtedly arise from the efforts he has unremittingly made to popular education. promote It is quite impossible that in our limited pages we can enter into a complete analysis of the whole of this excellent pamphlet; we must content ourselves with a few extracts, with enforcing a few of the topics it embraces, and with earnestly recommending to our readers the perusal of the pamphlet itself, a thing they will be more likely to do when we inform them, that it is published for behoof of the London Mechanics' Institution. What be advances in the following extract, is surely deserving of attention from every one; and we know nothing which will prove of more advantage to the cause of popular education, than the publication of good popular treatises on different subjects connected with science and the arts, such as he proposes. The idea of a society such as he mentions for the promotion of this purpose is praiseworthy, and it is much to be hoped that the design of forming it will not be allowed to fall to the ground. "In the third place, (he says,) it is evident that as want of time prevents the operative classes from pursuing a systematic course of education in all its details, a more summary and compendious method of instruction must be adopted by them. The majority must be content with never going beyond a certain point, and with reaching that point by the most expeditious route. A few, thus initiated in the truths of science, will no doubt push their attainments much farther; and for these the works in common use will suffice; but for the multitude it will be most essential that works should be prepared adapted to their circumstances.— Thus, in teaching them geometry, it is not necessary to go through the whole steps of that beautiful system, by which the most general and remote truths are connected with the few simple definitions and axioms; enough will be accomplished, if they are made to perceive the nature of geometrical investigation, and learn the leading properties of figure. In like manner, they may be taught the doctrines of mechanics with a much more slender previous knowledge both of geometry and algebra, than the common elementary works on dynamicks pre-suppose in the reader. Hence, a most essential service will be rendered to the cause of knowledge by him who shall devote his time to the composition of elementary treatises on the Mathema |