248 LATHE AND TOOL USED AT THE ROYAL ARSENAL, WOOLWICH. air or sound do to hearing, for it Water : 1,00000000000 sides of a parallelogram; the crescent end being applied to the screw cylinder on the mandril, the cutting point, of course, follows in a similar proportion, and cuts a fac-simile thread on the work submitted to it, and serves to effect an entrance for the screw tool. LATHE AND TOOL USED AT THE ROYAL ARSENAL, WOOLWICH. SIR,-I beg leave to forward for publication in your useful work, a description of a Lathe and Tool, which is, perhaps, not generally known, though it has been used in the Royal Arsenal here, for many years, to form the thread upon the screws used to bush the touch-holes of the brass cannon with copper vents; and as it greatly assists the workman in forming, or rather copying the screw, in a perfect and uniform manner, it may not be altogether unworthy of your notice. On that part of the mandril which projects beyond the collar of the lathe, hollow cylinders, of different threads, are occasionally fitted, and a piece of steel is flattened at one end, and worked into a kind of crescent, whilst at the other it is filed into a triangular point, to fit the required thread. The two ends of this tool are now bent at right angles to its centre, forming three DESCRIPTION. AAAA represent a strong frame of wood firmly fixed to the ground. BB, two screws fixed in the frame. CC, a large hollow screw, running in screws, BB. DD, the centre-bit (or borer), made a half-circle, like a gimblet, with a screw or half-cut on the end, like an auger, with holes in it, represented at DD, for pins, EE, to go through, and likewise through the large screw, CC, to join them. FF, a lever of wood, 15 or 20 feet long, and fixed to the top of the screw, CC. OPERATION. Say one man were placed at each end of the lever, by going round they screw down the screw, CC, and the borer along with it (while the pins, EE, are in), and when it comes down to the frame, they take out the pins, EE, and drive the lever the contrary way, which screws (the screw, CC), up to the pitch again, leaving the borer fixed. Put the pins, EE, a few holes higher, and proceed as before. The borer being a half-circle, and hollow, it follows that the earth and minerals will be forced up at the top, and the borer will be joined piece to piece, in the usual way, as it goes down. I am, Sir, yours, &c. 250 ADVANTAGE OF SCIENTIFIC KNOWLEDGE TO MECHANICS. ADVANTAGE OF SCIENTIFIC KNOW LEDGE TO MECHANICS. We extract the following convincing arguments in favour of the spread of scientific knowledge among the working classes, from the Inaugural Address of Mr. Heywood, the President of the Manchester Mechanics' Institution. "It has already been stated to you in the Prospectus, that the Institution is formed for the purpose of enabling mechanics and artisans, of whatever trade they may be, to become acquainted with such branches of science as are of practical application in the exercise of that trade;' and again, that there is no art which does not depend more or less on scientific principles, and to teach what these are, and to point out their practical application, will form the chief objects of the Institution.' Some of you may possibly think, that scientific principles can have little to do with your occupation; that, to learn your business thoroughly, nothing more can be necessary than to be diligent, during your apprenticeship, in your endeavours to imitate the skil fulness of those under whom you work. I will not deny that, by this means, you may acquire great dexterity in your occupation:-it is thus that the Indians, with whom the cotton manufacture originated, produce their beautiful muslins. All the implements they use, in the different processes of the manufacture, from the cleaning of the cotton, to the converting of it into the finest muslin, may be purchased for the value of a few shillings. With the exception of their loom, there exists among them no manufacturing instrument that can bear the uame of a machine; nor is there any trace of the Hindoos having ever displayed any mechanical ingenuity. They spin their yarn upon the distaff; the loom upon which their cloth is woven, is composed of a few sticks or reeds, which the weaver, carrying them about with him, puts up in the fields, under the shade of a tree, digging a hole large enough to contain his legs and the lower part of the geer, the balances of which he fastens to some convenient branch over his head. Two loops underneath the geer, in which he inserts his great toes, serve as treadles, and the shuttle, formed like a large netting-needle, but of a length somewhat exceeding the breadth of the cloth, he employs also as batton, using it alternately to draw through the weft, and strike it up. The loom has no beam; the warp is laid out upon the ground, the whole length of the piece of cloth. Upon this rude machine, worked in the way I have mentioned, the Indians produce those muslins which have long been such objects of curiosity, from the exquisite beauty and fineness of their texture.' But mark the other effects of this adherence to the same practice from generation to generation, to which, by their superstition, these poor Indians are bound. In India this manufacture has existed, almost in the same degree of perfection, for some thousand years, yet it has given birth to no inventions, to nothing calculated to improve the condition of the peoplethose who carry it on are in poverty and abject dependence. "In our own country, on the contrary, the cotton manufacture, as compared with the ages it has existed in India, is only of yesterday, yet it already constitutes more that one-half of our whole trade; and you may estimate its progress from the fact recently stated by Mr. Huskisson, in the House of Commons, that in the year 1765, the value of cotton goods exported from this country was 200,0007.; in the last year it was upwards of 30,000,000. It has given birth to inventions to which we are mainly indebted for our present preeminent station and prosperity; and, what is more to the point in this case, which have enabled us to receive from the Indian the cotton which grows at his door, to manufacture it into a shirt to cover him, and to send it back to his own country, and sell it to him, cheaper than he can provide it himself. that the undeviating adherence to esta"I need not say more to convince you blished practice-the mere imitation of what others have done before-precludes all advancement; it reduces man to the condition of a machine. Skill thus ac quired is little better than an instinct, and it has been well observed, that you are as little entitled to expect improvement in such a case, as in the architecture of the bee and the beaver. "If this course had been pursued in our own country, we might now have had no other mode of spinning cotton than on the cottage wheel-no other mode of bleaching a piece of cloth, than by the tedious process of exposure for months in the open air. "But if, when you are at your work, you are not satisfied with merely doing what you have seen others do, but try to find out the reason for each operation that passes through your hands, and the principle on which it depends, you are then in the sure way of making improvements in your trade. Nay, if you only observe accurately each operation in which you are engaged, you are already on the threshold of improvement. ADVANTAGE OF SCIENTIFIC KNOWLEDGE TO MECHANICS. "Hargreaves, the weaver, who invented the spinning jenny, was first directed to the invention by seeing a common spinning-wheel, which had been accidentally overturned, continue its motion while it lay on the ground. This was the first great improvement in spinning, and it resulted merely from the attentive observation of an active and inquiring, but altogether uneducated mind." "The ingenious contrivance for regnlating the valves of the steam engine, was discovered by a sharp lad, who set his wits to work to see if he could not lessen his own labour. "Mr. Watt was led to his first improvement in the steam engine from his observations when he was employed to put in order a working model of an engine on Newcomen's construction. He soon discovered some material defects in its principle: one of these defects he remedied before the model left his hands; others he was not at the moment able to account for his vigorous mind, however, applied itself at once to their thorough investigation. Science, ere long, emoved his difficulties, and led him to the invention of the separate condenser; affording you a striking example of the practical application of the principle of latent heat. "I fear the minute details of the successive steps, by which Mr. Watt proceeded in this, and his other greater improvements of the steam engine, might occupy too much of your time at present. They will be found in his life, and are very interesting: nothing can convey to you a stronger idea of his sagacity, ingenuity, and scientific attainment, or more strongly enforce what I wish now to impress upon you-the connexion of the principles of science with manual labour. There cannot, indeed, be a more beautiful and striking exemplification of the union of science and art, than is exhibited in the steam engine. "You have another (in two senses of the word) bright example of the same union, in the light with which this theatre is illuminated. To the introduction of this admirable practical application of the gas from coal, we are indebted to Mr. Wm. Murdoch. He was first led to his experiments on the subject, by observing the brilliant flame, which you must all have frequently seen issue from coals ou the fire at the commencement of their ignition. He pursued his inquiries with great ability and perseverance for several years, by subjecting a great variety of substances to distillation by ardent heat, and carefully investigating their various products; but he made no attempt to carry his discovery practically into effect, until he had, in a great measure, brought it to perfection. In the 251 year 1805 he commenced preparations for lighting with gas the large factory of Messrs. Philips and Lee, in this town (Manchester), in which he completely succeeded. The example was soon followed by others, and how generally it has been extended, and with what beneficial effects, I need not tell you. "There are two very beautiful examples of the union of science with art in the safety lamp, and in Hall's singeing machine. To the construction of the first, Sir Humphry Davy was led by finding that flame would not, under ordinary circumstances, pass through an aperture less than one-twentieth of an inch in diameter. In the other, by the interhas cansed flame to pass through the invention of a partial vacuum, Mr. Hall terstices of the finest muslin. "But I wish to bring more immediately home to you the application of science to your occupations. The mechanic, whose knowledge of his business is coufined to the skilful handling of his tools, is in no way of improvement: he must learn also the nature and properties of those materials on which he workstheir relative weight, hardness, toughness, strength-the effects upon them of heat, gravity, position, &c.; these involve principles upon which his art depends, and these will be taught him here. "The art of the carpenter is directed, almost wholly, to the support of weight or pressure, and, therefore, its principles must be found in mechanical science. "The great improvements in the art of bleaching depend immediately on certain principles of chemical science, which Mr. Watt, and your late venerable and enlightened townsman, Mr. Henry, were the first practically to apply in this country. "The improvements in the art of calico-printing and dying have the same immediate dependence on chemical principles. "These examples may suffice to shew you, that the principles of science are applicable to your business. It matters not what that business is: I have taken my examples from those trades in which the improvements are prominent, but similar reasoning applies to all. "It is the great object of this Institution to put you in the way of acquiring the knowledge of these principles, and to show you how you may most readily make this knowledge available to your advantage-to remove the difficulties which now obstruct your further advance to teach you so to observe, that your observation may be profitable to you," SIR, The annexed figure represents a Pump, described by M. Ozanam in his Récréations Mathému tiques et Physiques (Paris, 1750), which appears to be much superior to the pumps now in use, though I have never met with a notice of it in any other work. Its action and construction may be easily understood by the figure. A is the working cylinder; B, the piston, or plunger, the rod of which, D, works, in an air-tight manner, through the stuffing-box, C. E is the suctionpipe, or pipe leading from the well; and H, the discharging-pipe. FF and GG are valves, all opening upwards. The piston is represented as ascending, and therefore the valves at FF are open, and at GG shut. I is the plate closing the bottom of the cylinder, and by which the whole may be securely bolted down to the work supporting it. It will easily be seen, that this pump raises water both in the ascending |