ship. For example, where the bow is very sharp the middle and the fore edge of the rabbet will fall very near together, and will separate again as the bow becomes more bluff. To determine this line, it will be necessary to find several points in it in the following way. Draw a short level line AB at the place where it is desired to find a point in the required line, and let the line AB meet the fore edge of rabbet in the point a'. It must be observed that the stem tapers from the under-side of the lower cheek' to the fore-foot', as shown (Fig. 16), so that the horizontal projection of the point in the fore edge of the rabbet corresponding to a' will be a, lying in the line a a' drawn perpendicular to LT, and at a distance from the axis equal to the half breadth of the stem at the height of the level line. Now, what we desire to do is to set in from the point (a, a) the thickness of the plank, say four inches, in a direction at right angles to the surface of the planking at (a, a') because 4-inch planking measures more than four inches in any direction not square to its surface. We see that a small portion of the surface of the bottom at (a, a') is a plane containing a short piece of the line e d, and also of the level line A B. If we can discover this plane, it will be easy to draw a line through (a, a) perpendicular to it, and upon such line to set off the 4 inches. Draw then, the line a' b' coinciding with c d at a' and extending down to L T, which is drawn at a distance equal to the thickness of the plank of bottom above the lower edge of the rabbet of keel, and is called technically the upper edge of the rabbet of the keel. It forms a convenient base line or axis, but it represents nothing in the ship. The line a'b', thus drawn, will be the vertical projection, and a b drawn with the taper of the stem the hori zontal projection of the tangent to c d at a'. We must now find the projections of the tangent to the level line at a'. For this purpose a penning batten must be passed through the points obtained on the sections for the level line, and brought down to touch the back of a circle swept from a, with a radius equal to the thickness of the plank. This will give us a very close approximation to the direction of the surface, and a line ae drawn parallel to the foremost portion of the approximate level line may be assumed to be the horizontal projection of a tangent to the outside of the planking in the section A B, and at the point (a, a'); the vertical projection of this tangent is a' e'. The horizontal trace of the plane which contains these lines, must contain the horizontal traces of the lines. Now, (a e, a'e) has no horizontal trace, and that of (a b, a' b') is b. Moreover, the horizontal trace of a plane containing a line parallel to the plane of projection must be parallel to the horizontal projection of the line, from which we conclude that CD drawn through b, parallel to a e, is the horizontal trace of a plane containing the lines (a b, a'b) and (a e, a' e'). Again (i, i) the vertical trace of (a e, a' e'), must lie in the vertical trace of the plane we seek; this trace is, therefore, Di' or DB and the tangent plane to the surface at (a, a) i BDC. From a draw a' f' perpendicular t BD, and from a draw a f perpendicular to D then (af, a'f') is a line drawn from (a, a') perpe dicular to the plane BD C. It may be of ay length. Having determined its length by markig the point (f), we must proceed to rabat itin order to discover the true distance between (a) and (ff). This true distance is the hypotheuse of a right-angled triangle of which the ba is af, and the perpendicular the distance wich one end of the line is within the other, i.e., d, so that if we draw fF perpendicular to af and equal to a h, and join a' and F, a' F will the true length required. It is on this lin a F which is a normal to the surface at a', tht the thickness of the plank is to be set off. et off then a' G equal to the thickness of the plak, and draw G g' perpendicular to a f'. It will be en that if a' F were swung back about af until ireached its proper position-perpendicular to the surface of the planking-a' G would be a line a'oss the square butt of the plank, and also perpendicular | find the bearding line along the keel, measure the Parliamentary Proceedings. CONDENSED FOR THE "MECHANICS' MAGAZINE." HOUSE OF COMMONS. PIERS AND HARBOURS. Mr. FINLAY asked whether it was the intention of Her FRIDAY, MARCH 11. HOUSE OF COMMONS. The order of the day for going into committee of supply think it would be quite prudent to state how many of Arm- DOCKYARD EXPENDITURE. portion of the normal must always be to the cut by straight lines representing the half-siding of the stem at the height of the respective lines. The bearding line on the stern-post and after deadwood are obtained in the same manner. To A lengthened discussion then ensued on Dockyard When the House divided the numbers were- Majority against the motion. MONDAY, MARCH 14. 97 117 -20 METROPOLITAN DRAINAGE. Metropolitan Board with reference to the main drainage Mr. TITE had obtained from the chairman a correct account of the present state of the works. On the south side level and the few were. Wehe highs lof of werver began at of the river two systems sewers-the Clapham and ended at Deptford; it was 10 miles in length, and its estimated cost was £203,000. The contracts for this sewer had been concluded last week. The lower level sewer began at Putney and ended at the same point as the tracts it be higher one-Deptford; it was 11 miles long, and the consystems of drainage on the south side of the river would end at the same point at Deptford Creek, where the contents of the lower sewer would be pumped into the higher one and flow into the estuary of the Thames at Erith. On the north or city side of the river there were three systems of sewers; one began at Hampstead, and ran for seven miles and a quarter to a terminating point on the river Lea. The cost of this sewer was estimated at £252,000, and it would probably be finished in 12 months. The second sewer began at Kilburn, and ended at the same point on the river Lea as the first-a distance of 10 miles; it would be contracted for at the end of the year. The third system, being involved with the embankment of the Thames, would require a longer time in construction. All these systems meeting at one point on the Lea, the water would there be raised from the lower to the higher level, and run in a common conduit to the sea at Barking Creek. The works would be completed in four years; the whole of the money, £3,000,000, had been advanced by the Bank of England, at 3 per cent. It was estimated it would all be paid off in 40 years by a 3d. rate on the metropolis. THE NAVAL ESTIMATES. On the question that the House may go into Committee of Supply upon the Naval Estimates, Mr. WILLIAMS moved that they should be referred to a select committee. After remarks from Sir H. Verney, Sir H. Willoughby, Mr. Lindsay, Col. Sykes, Admiral Walcot, Sir F. Baring, Mr. Bentinck, Lord H. Vane, Lord C. Paget, Sir J. Pakington, Mr. B. Osborne, Sir C. Napier, Mr. Jackson, and Sir C. Wood, Mr. Williams' amendment was negatived without division. DECIMAL COINS FOR CANADA. THE coinage of decimal pieces for Canada still goes on at the Mint simultaneously with the ordinary coinage for home use. More than three Ex-millions of twenty, ten, and five cents, equal in weight and value to the franc, half, and quarterover the water," franc of our belligerent friends" have already been despatched to that colony, and now one-cent coins of bronze are being produced. This latter may be considered, indeed, a model coinage. It is at once economical, artistic, and convenient. The bronze used is a mixture of copper, tin, and zinc-in the proportions of 95, 4, and 1-and thus gives a metal harder and more durable than copper alone. The pieces are, in comparison with our own copper currency, thinner and larger in diameter. For instance, farthings are 7-8ths of an inch in diameter, and there are 96 of them to the lb. avoirdupois; but the Canadian one cents are just an inch across and there are 100 of them to the lb. When it is considered, too, that they are current at the same value as the halfpenny, the economy of metal becomes at once apparent. The design of the obverse is chaste and pretty. Her Majesty's portrait, with the legend, VICTORIA, REGINA DEI GRATIA, CANADA, surrounded by an undulating wreath of maple leaves, comprises it. The reverse has a similar wreath, with the words, "One Cent," and the date, "1859," in the centre. Twenty tons' weight, or nearly 44 millions, of these admirable coins are being, we are told, struck, and certainly the Canadians may be congratulated upon presently obtaining a perfect decimal currency, whilst the English people are but thinking about adopting the valuable improvement. Why should the population of these islands-to put the matter in a point of view as regards convenience only-be always carrying about 6,000 tons of metal in the shape of copper Sir J. PAKINGTON said, in consequence of the statement coins, when 3,000 tons or less, of bronze, well made to the House on Friday evening by the noble lord the adapted for wear and tear, and for displaying the member for Sandwich (Lord C. Paget) that, in the course of the last 11 years, of the sums voted from time to time fine lines of the engraver, would answer the same by the House of Commons for the expenditure of our dock-purpose? When, indeed, may we expect a deci yards, no less than 5,000,0001. have not been accounted for, mal coinage ? or have been absorbed by what the noble lord called reckof a day or two it is my intention to lay on the table, together with the reports of the committees I have already House during these 11 years has been appropriated. And promised, a full statement of how the money voted by the it is my intention that this statement shall be given as much in detail as it is in the power of the department of the Surveyor of the Navy to supply. ELECTRIC TELEGRAPH GUARANTEES. The Earl of DONOUGHMORE said there would be no ob jection to the return. Lord REDESDALE objected altogether to the principle of guarantees. They were entirely unnecessary, and had the effect of deterring the construction of useful works, for when once the practice was established no work would be undertaken without a guarantee. The return was then agreed to. HOUSE OF COMMONS. DOCKYARD EXPENDITURE. Mr. W. Phelps, of Red Lion-square, London, suggests "the employment in wet gas meters of earthy salts, kept constantly neutral by the an aqueous solution of deliquescent metallic and presence of a base or carbonate," instead of the ordinary water, MANCEAUX'S METALLIC STOCKS FOR M. François Jules Manceaux, of Paris, one of block inserted into the shell of the stock on the side opposite the lock-plate, for the purpose of giving additional solidity of the stock at that part, and for maintaining the barrel in the centre of the stock; this block is traversed by the screw d'. At the further end of the stock there is a ring, P, which encircles the barrel, and is secured to the stock by a screw. If thought necessary, in order to protect the extreme end of the barrel, the wooden bed might be prolonged, and fastened by rings to the barrel, as in the ordinary military musket. The wooden bed should be covered over its whole length with leather, and then the leather sheath might be composed of two parts united at the breech, or other suitable part; m is the guardplate screwed to the under part of the shell, and the guard; o is the trigger which works in a slot made in the shell; qq' are buckles for attaching a sling. STEAM FIRE-ENGINES. sectional elevation of a pistol stock, showing the | in the rear of the barrel; h is a strengthening lock. The patentee first forms moulds and dies in metal, and then by successive heats, and under hydraulic or other pressure, fashions a sheet of plate-iron into the form required. He brazes the edges of the plate, and makes a perfect joint. This is the shell or carcass of the improved stock. He next furnishes the interior of the rear-end of the shell with a Z-shaped strengthening piece, a', Figs. 1 and 9, to prevent the sides collapsing, and with two nuts, ff', screwed to the shell to receive the ends of screws for holding the butt plate of the stock. The fore part of the metal shell is filled with a bed of wood, c, Figs. 1, 8, and 14, hollowed out at top, and riveted to the shell. He next takes a hide, b, of the shape shown, and sews it up at the sides to form a sheath. The leather is softened by steeping, and while wet, or damp, is drawn over the metal shell and wooden bed until the two open ends extend beyond the shell; a false barrel is then placed over the leather, and secured over the wooden bed by screw or other clamps, to cause the leather to assume and follow the shape thereof. A wooden block is introduced between the turned-over edges of the leather at the breech, see Figs. 1, 4, 7, 8, and 9. In drying, the leather follows the exact form of the shell, and in order to dry it thoroughly, he introduces and works about a hot iron inside of the hollow part of the stock. He next plunges the stock in melted wax, and rubs the wax into all the pores of the leather. He then allows the wax to drain off, and the stock to cool; when cold he polishes the waxed leather with a rubber and brush. One end of the sheath is turned in over the butt-end of the shell, and is covered and secured by a rim, e, in the inside of Fig. 1 is a longitudinal section of the stock of the butt plate, which is attached to the nuts ff' a fire-arm constructed according to this invention, by the screws e', e'. The opposite end of the and showing the lock. Fig. 2 is an external ele- sheath is turned in over the wooden bed. The lock vation of part of the stock, showing a plate on the is placed bodily in the hollow of the shell, and is side of which the hammer is to work. Fig. 3 is a there fixed by screws, see g' g, Figs. 1 and 5; k is cross section. Fig. 4, cross section through the the hammer, secured on the spindle by the screw line e f of Fig. 5, which is a longitudinal section; g is the lock plate held inside the shell by the through c d of Fig. 4; Fig. 6 is also a longitudinal section through c d of the opposite side of the arm; Fig. 7 is a cross section through g h of Fig. 1; Fig. 8, cross section through k l of Fig. 1; Fig. 9, cross section through m n of Fig. 1; Fig. 10 is an internal view of the butt-plate; Figs. 11, 12, and 13, are cross sections respectively through the lines o p, qr, and s t of Fig. 10; Fig. 14 is a contained in the hollow of the stock, and is held by screws; a transverse screw bolt passing through a hole formed in a block on the bottom of the breech-end of the barrel keeps the barrel in place. A metal plate is screwed in outside the leather to receive the friction from the working of the hammer of the lock. screws g', g; is a metal collar screwed to the TO THE EDITORS OF THE "MECHANICS' MAGAZINE." Fire Engine and Pump Manufactory, 245 Blackfriars Road, London, 16 March, 1859. GENTLEMEN,-Referring to the number of the Magazine dated the 4th instant, we find several strictures by an anonymous correspondent upon our Steam Fire-Engine, but as we have two in hand nearly completed, with which we intend to have various public trials, we decline, at present, entering into a controversy upon the subject; at these trials your correof acquiring the fullest information. With regard to spondent and the public will have ample opportunities that part of his letter in which he states that the attempt to work the engine in St. Petersburg proved a failure, we beg leave to hand you the following letter: "Messrs. Shand and Mason. "March 15, 1859. the cold being 18 Reaumer, nevertheless she performed SHAND AND MASON. MACHINERY FOR TURNING. ON SOME APPLICATIONS OF THE COPYING OR TRANSPER PRINCIPLE IN THE PRODUCTION OF WOODEN ARTICLES. BY JOHN ANDERSON, ESQ., F.R.S., Inspector of Machinery, Woolwich Arsenal.* A distinguishing characteristic of the arts and manufactures of the present century as compared with those of the past consists in the application of the principle of machine copying, in contradistinction to dependence on the skill of the operative, in the production both of the ordinary articles of commerce and of the munitions of war. Engineers are so familiar with this principle in their every-day pursuits, that it frequently escapes their notice; yet a closer inspection will show that almost all machines that are intended to change the form of materials are constructed on some modification of this principle, of having the form in some way or other contained in the apparatus, with the specific object of imparting that form to the materials under operation; and it will generally be found that every process which is done well, and which at the same time is done cheaply, is performed by some skilfully-arranged development of this principle. The advantage of keeping first principles steadily in view in practical applications of science is generally conceded: the knowledge of facts is considered good; but to know the law of the facts is considered better, and much more likely to hasten onwards their more extended application. A complete exposition of the various applications of this copying principle in the several arts and manufactures of the world would form a highly interesting and valuable Volume. Within the last few years a remarkable change has taken place in this respect. With regard to the tools of the smithery, production by the hammer and hand of the smith is fast giving place to production by means of apparatus constructed upon the copying or transfer principle: such as dies under the American drop hammer, the steam hammer, and the forging machine; the employment of rolls containing on their surfaces the pattern of what is wanted; and the use of oscillating dies imparting the form to the red hot mass upon a moving table. In each case it is seen that the general tendency is to obtain the form and dimensions of the article produced by the transfer of both from an apparatus prepared with care; and to dispense with that care in the future actual production. The moulding operations of the foundry are pre-eminently copying; or, if it is attempted to analyse the recent improvements in the moulding of wheels, shells, railway chairs, and such articles, it will he found that all are designed with a view to have te accuracy and perfection of form provided in the apparatus, from which it is then transferred to the sand without so much skill being required on the part of the workman who performs the ramming of the mould. The other workshops of the engineer present that invaluable development of the copying • Paper read at the Institution of Mechanical Engineers. principle termed the slide rest, assuming every variety and modification in the several machines used for turning, boring, drilling, planing, or shaping. The same principle in combination with circular cutters affords the machinery of the Small Arm Factory, the endless variety of which would alone form an interesting subject. proper diameter without the risk of digging into the mass and thereby breaking the cutting instrument, a small wedge of wood, F, is attached by a loop to the little finger of his right hand, and at the commencement of the operation is inserted between the toolholder E and the irregular pattern C at the back of the lathe, but is gradually withdrawn as the article approaches the required diameter; and at the last, a finishing tool is slowly and carefully drawn along the two guides B and C, thus producing the exact pattern without any effort, and in much less than half the time in which it could be done in the common way. On a similar plan to the foregoing, but differently arranged, is the American system of turning long poles of small diameter, as shown in Fig. 2. The wood, G, to be turned is first cut by a circular saw into square rods of the required length; these are then placed between the centres of a turning lathe, with the corners still upon them. The toolholder or cutting apparatus, H, slides steadily upon two parallel straight edges, II, placed respectively at the front and back of the lathe: this toolholder consists of a metal socket, H, having cutting gouges, K and L, at The object of the present paper is to give a descrip- each end; the foremost gouge, K, is set to reduce the tion of a few applications of the copying principle in square rod to the internal diameter of the socket, H, the production of certain articles mostly in connec- in order to obtain perfect steadiness; while the second tion with the simple operations of wood-turning, or finishing gouge, L, is set to reduce the pole to the which have been more immediately brought under required diameter. To relieve the workman from the the notice of the writer; and although they are trouble of pushing the socket, H, with its cutting trifles in themselves, still it is only by each one tools along the lathe, the interior of the socket is making a small contribution from time to time that made with a screwed surface; and the first gouge, K, the improvements in the details of the several work- being set to give a tight fit, the thread which is thus shops can be made generally known to one another. formed upon the wood draws the socket along; and as the second gouge, L, is close to the hinder end of the socket, the thread does not make its appearance, being cut off by the second gouge, which is set to give the proper finished diameter to the work. In turning long small poles of an irregular figure, the second tool, L, is not a fixture upon the socket, but is held in a toolholder having one end hinged upon the socket while the other traces the required pattern placed alongside, thus causing the tool to rise or fall as it slides along the pattern. During a short professional tour in the United States in 1854, the writer was much struck with the many simple and ingenious contrivances there introduced, in order to apply the copying principle in connection with ordinary hand-lathe operations, where generally in this country more would be dependent upon the skill or attention of the turner or upon special machinery. For example, in the production of articles where there is repetition and which are to be turned in a common lathe, the application of certain very simple additions tends greatly to facilitate the operation, and to enable the operator to dispense with the usual measuring and gauging and the use of callipers, which generally occupies so much time. A simple arrangement of a copying lathe is shown in Fig. 1. At the front of the lathe and parallel with the piece of wood 4 to be operated upon, there is fixed a strait edge, B, made of hard wood, with the upper or straight edge slightly hollowed. At the back of the lathe there is a similar fixture, C, only the upper edge is not straight but resembles the irregular form of the required article. The gouge or turning instrument, D, instead of being held in the hand of the turner over a rest, is fixed into a piece of wood, E, the arrangement slightly resembling that of a carpenter's plane, having one end adapted to slide firmly on the straight edge B, at the front of the lathe, while the other is adapted to trace the irregular line C, running along the back. In order that the workman may gradually reduce the wood to the It may be mentioned that the American woodturners use a centre which is not common in this country; and having been introduced into the Royal Arsenal with great advantage, its general application can be recommended. This lathe centre, which is shown in Fig. 3, instead of having the ordinary sharp point, is formed at the extremity with a hollow cup, M, surrounded by a sharp circular edge; this when pressed into the revolving wood forms a hard centre within itself, by compression of the wood within the conical cup, which is better adapted both to retain the oil and also to continue uninjured during a long period. The method of turning the sabots or blocks of wood which are attached to round shell, as performed in the arsenal at Woolwich, affords another illustration of the successful application of the copying principle. Hitherto these articles have been produced by the wood-turner with the gouge, chisel, and gauges, in the usual manner; it was a monotonous and very laborious process, and a skilled workman could produce only about fifty of them per day. By the new method, the wood is first cut out of the plank into circular pieces by means of an ordinary trepanning tool, costing for wages an average of 7d. per hundred. The wooden disc is then perforated by a drilling machine, in order to prepare it for being screwed upon the face plate of a turning lathe. The first turning process is to form the exterior surfaces; and for that purpose the wood is screwed upon the centre screw of the face plate, as shown at 4, Fig. 4. The tools or gouges, B and C, that are required to produce the form are contained on separate sliding rests, D and E, combined together upon one saddle, F, both being actuated by the movement of a single handle, G. The saddle, F, itself is made to the lathe bed in the ordinary manner, by means of a rack and pinion, and is moved by the left hand of the workman by means of the handle H. The dimensions of the sabot are determined by a stop upon the lathe bed against which the saddle, F, is pressed, and also by the adjustment of the gouges. The next and last operation is to hollow the sabot for the reception of the shell. For this purpose a similar lathe is employed, shown in Fig. 5; the block, 4, is held in a universal chuck adapted to the article. The required hollow being part of a true circle, the gouge, B, is fixed upon a holder which is capable of turning on its axis by means of a handle, C; the radius of the circle described by the gouge depending on the distance at which its cutting edge is set from its centre of motion. The toolholder is mounted upon the saddle, D, of a lathe, as in the former operation, the depth to which the hollow is cut being determined by a stop fixed upon the lathe bed and adjusted with reference to the face plate. In performing the operation the workman moves the saddle, D, with his left hand by a rack and pinion by means of the handle E, while with the other hand he gently moves the handle, C, of the toolholder, making the gouge describe an arc of a circle. It will thus be seen that no skill is required during any of the producing operations, and that the form and dimensions of the article are in each case contained in the apparatus. To make sabots of other forms, the several slide-rests are readjusted upon the saddle. The saving in wages effected by these arrangements amounts to more than four-fifths of the original cost. For another but smaller class of articles of similar shape, of which three or four hundred thousand are required daily, a different modification of the principle of copying is employed. The conical plug of the Minie bullet is made of boxwood by self-acting machinery. In this manufacture, the conical form of the plug is contained in a revolving cutter, which is fixed in a lathe spindle and driven at a high velocity. The wood having been first cut up into long square rods by means of circular saws, one of the wooden rods is fixed upon the lathe saddle, and pushed forward against the cutter; this gives a conical form to the end of the rod, which is then cut off by means of a circular saw, forming a plug of the required shape and dimensions. of common agents on the metals in general use has been little studied. Aluminium, like iron, does not unite with mercury, and scarcely at all with lead. It, however, forms a variety of alloys with other metals. Looking at the various remarkable properties which this metal possesses, it is impossible not to see an immense variety of uses to which it may be applied. Already its lightness and colour has brought it into use for jewellery and ornaments of va rious kinds-bracelets, combs, pins, seals, penholders, tops of inkstands, portemonnaies, shirt studs, harness, statuettes, candelabra, candlesticks, &c. Its ductility and fusibility render it readily stamped and cast. It works easily under the graver, and being unaffected by the atmosphere it has an advantage over silver. Its lightness renders it peculiarly fitted for spectacle-frames, eye-glasses, telescopes, and opera-glasses, to which uses it has already been largely applied. It does not stain the skin as silver does. The alloys, too, or aluminium bronzes, as they may be termed, are peculiarly fitted, from the readiness with which Mr. Gerhard, an Englishman, has for some little time past been engaged in experiments with a view to establish the manufacture of aluminium in this country, and to produce it at a cheaper rate than hitherto. He has adopted the cryolite process rather than the double chloride of aluminium and sodium, inasmuch as the cryolite is readily obtainable in large quantities and at a very low price. Mr. Gerhard has erected furnaces at Battersea, and there is no reason to doubt that with the modifications which he has introduced, added to the fact that the materials are cheaper in this country than in France, aluminium may be produced here at a still lower price than in France, whence the small quantity that has been used in this country has hitherto been imported. Mr. Gerhard's process he shortly describes as follows:-270 parts by weight of powered cryolite are mixed with 150 parts of common salt, and into this mixture are placed 72 parts of sodium, cut into small pieces. The whole is then thrown into a heated earthenware crucible, which mixture is also immediately poured over the contents they are worked, and their not changing under the action of cryolite and salt, the over 7s. 6d. per oz., and of the atmosphere, for the wheelworks of clocks and chro- a which the lid is then placed. The crucible is then put in a furnace, and kept at a high red heat for about two hours. When the pot is uncovered the melted mixture is well stirred, and then poured out. The buttons of aluminium are found mingled with the slag, and may be easily melted toTheoretically, the amount of aluminium produced should gether by heating them in a crucible with common salt. be one-third of the weight of the sodium employed, but practically such a result is never obtained, and our manufacturers would be well satisfied with obtaining between one-third and one-fourth. This Mr. Gerhard has accomplished, though he is not always so successful. There is still some uncertainty in the process. "From what I have seen, and from what I have learnt from those better qualified to judge on matters of chemistry and metallurgical operations than myself, I am led to believe," said Mr. Foster, "that the cryolite process is the one that will ultimately be preferred to that of the chloride of aluminium." As yet, however, the process presents certain difficulties which Mr. Gerhard appears to have to some extent overcome by his method of performing the operation. Previous to Deville's labours, aluminium sold at the rate of £40 sterling for 35 oz. avoirdupois; and when Deville came to England, in 1856, the result of his labours had then already caused a reduction in the price to £3 per oz. Mr. Gerhard already manufactures sodium commercially, and owing to his labours, the price of sodium has been considerably reduced, being now sold at 16s. per pound avoirdupois, while two years ago the price of imported sodium was £6 sterling per pound. Aluminures no doubt that if large quantiimported from France, fetches ties of it were required the supply would be made at once at a considerable reduction on this, which may be termed a retail price. There can be no reason to doubt that at no distant period it will be produced at a cost which will secure its application to numerous important uses. "I may add," said the author, "that while engaged in the preparation of this paper, I have been informed, and I have no reason to doubt the truth of my information, that certain modifications are likely to be introduced into the manufacture of sodium, so as to enable it to be produced at a marvellously reduced price, which will affect in a proportionate degree the cost of aluminium." He next noticed the properties of this remarkable metal. One is its extreme lightness, its specific gravity being 2-6, nearly that of glass, whilst that of platinum is 21.5, gold 19-5, silver 10-5, copper 8-96, zinc 7.2, tin 7-3; and in comparing its price with these metals this quality must be taken into consideration. Thus, if one ounce of silver is required to make a spoon, the same weight of aluminium will make very nearly four. reduced to very thin sheets, or drawn into very fine threads. metal is malleable, ductile, almost without limit; it can be Its tenacity, though superior to that of silver, is less than that of copper; but no very accurate experiments have been made in this respect. When pure it is about as hard as silver. Its elasticity is not great. It files readily, and is said not to injure the file. It conducts electricity with great facility, so that it may be considered as one of the best conTHE NEW METAL ALUMINIUM. ductors known, almost equal in this respect to silver, and more than eight times a better conductor than iron. It A VERY interesting paper on aluminium was read melts at a temperature a little above that of zinc, between at the Society of Arts, on Wednesday, the 2nd zinc and silver. In its chemical qualities it would seem to ult., by Mr. Foster, the able Secretary of that take an intermediate rank between what are termed the noble metals and the common metals, being, as Deville Society. First mentioning the extension which states, one of the most unalterable of metals. It might be chemical knowledge has undergone in modern imagined that it would as readily re-assume its oxygen as times, and the boundless supply of aluminous sub- it parted with it with difficulty when in a state of oxide. stances which has thus been opened up-in ferent to oxygen as either platinum or gold. In air and in This, however, is not the case; it appears to be as indifgranites, slates, schist, and especially in clays-oxygen it undergoes no sensible alteration, and it even rethe author pointed out the fact that aluminium sists it at the highest temperature which Deville could produce in a cupelling furnace, a temperature higher than forms an essential portion of our most brilliant that employed in assaying gold. Water has no action, acgems, including corrundum, the sapphire, and the cording to Deville, on aluminium, neither at its ordinary Oriental ruby and emerald; and then proceeded to temperature nor when boiling, nor even upon the metal at a low red heat, near its melting point. (According to remark that, notwithstanding the universal difProfessor Crace Calvert, this statement must be received fusion of ores of aluminium, the existence of the with some degree of caution, as he considers that oxydation takes place slowly where the metal is immersed in water sulphur or sulphuretted hydrogen, like silver, nor is it for any considerable length of time.) It is not affected by But this would be perpetual motion giving acted upon to any considerable degree by any of the oxy- surplus of power, to attempt which is universally acids in the cold; nitric acid, whether strong or weak, at and proverbially held to be absurd. its ordinary temperature, in no way affects it, though when boiling it acts upon it slowly. Small grains of aluminium, absurdity, however, as impossibility is an assumpplunged in sulphuric acid for three months, remained ap- tion which, by the laws of reason, cannot be parently unaltered. The vegetable acids, such as acetic, opposed to a legitimate conclusion founded oxalic, and tartaric acids, have scarcely any effect on it at which attacks it rapidly. It appears to resemble tin when pepetuity of motion is indeed proved to be possiall. The true solvent of the metal is hydrochloric acid, admitted laws of nature and rules of art. Simple brought into contact with hydrochloric acid and the chlo-ble in a model at Woolwich. More was unattainrides. Its absolute harmlessness permits of its being employed in a vast number of cases where the use of tin would not able as long as the experiment was tried solely on be desirable on account of the extreme facility with which the principle of the first law of motion, and the that metal is dissolved in the organic acids. But the effect single force relied upon was momentum. But it (To be concluded in our next.) metal itself was not known until the last halfcentury, and its extraction has been attended by great difficulty. He then detailed the means adopted for producing sodium by Davy, GayLussac, Thénard, Mitscherlich, Brunner, Donny, Mareska, and, more recently, Deville; and traced the labours of Oersted, Wöhler, and Deville, in the production of aluminium. After quoting from the paper read by the Rev. J. Burlow, in 1856, on Deville's process, noticing the modifications which Paul Morin introduced, and sketching the labours of Dr. Percy, Mr. Dick, and Rose (of Berlin), the author stated that The friction. ON A QUICK-WORKING POWER ENGINE (Concluded from page 158.) THE MOTIVE POWER. It being not impossible that, after all that has been said, a reader might still ask the question, the explanation is here given that the motive power at first would be in several deposits of power, by the position of the pistons giving some advantage springs, by the pressure of air in a vessel towards of gravity in the water, by the tension of the the perpendicular tapering pipe on the reservoir, a vacuum, and by the bearing off the contents of and through it against the lower piston which was to be forced up and was to pump down the upper one resisted by general friction only, and that afterwards it would consist in the acquired superiority of the internal force, together with momentum over the resistance. The |