16 



GOLD.— SOCIETY OP ABTS.— ELECTEO-MAGNETIC ENGRAVING MACHINE. 



[1854. 



6th. Specimen of road Btone -wilh which Birmingham streets are 

 macadamized. 



7th. Ditto in a state of powder. 



8th. Ditto, purified by hydrochloric acid. 



9th. Specimen of sheet brass coated with silioium from this road 

 stone. 



BiKJiiNGHAM, 24th Mauoh, 1854. 



The Society of Arts. 



Gold— Its Distributiott-* 



Notwithstanding the preceding sketch, it would ill become any 

 geologist who -throws his eye 0¥er the gold map of the world prepared 

 by Adolf Erman, to attempt to estimate, at this day, the amount of 

 gold which remains, like that of Australia, undetected in the Tast regions 

 of the earth, as yet unknown even to geographers; still less to specu- 

 late upon the relative proportions of it in such countries. At the same 

 time, the board features of the case in all known lands may be appealed 

 to, to check extravagant fears and apprehensions respecting an exces- 

 sive production of the ore. For we can trace the boundaries, rude as 

 they may be, of a metal ever destined to remain precious on account 

 of those limits in position, breadth, and depth by which it is circum- 

 scribed in Nature's bank. Let it be borne in mind that, whilst gold has 

 scarcely ever been found, and never in any quantity, in the secondary 

 and tertiary rocks which occupy so large a portion of the sui-face, mines 

 sunk down into the solid rocks where it does occur have hitherto, with 

 rare exceptions, proved remunerative ; and when they are so it is only 

 in those cases where the rocks are soft, or the price of labour low. 

 Further, it has been well ascertained, whatever may have been the 

 agency by which this impregnation was effected, that the metal has been 

 chiefly accumulated towards the sm-face of the rocks ; and then, by the 

 abrasion and dispersion of their superficial parts, the richest golden 

 materials have been spread out, in limited patches, and generally 

 near the bottom of basin-shaped accumulations of detritus. Now, as 

 every heap of these broken am-iferous materials in foreign lands hasas 

 well defined a base as each gravel-pit of our own country, it is quite 

 certain that hollows so occupied, whether in California or Austraha, 

 must be dug out and exhausted in a greater or less period. In fact, all 

 similar deposits in the Old or New World have had their gold abstracted 

 from heaps whose areas have been traced and whose bottoms were 

 reached. Not proceeding beyond the evidences registered in the stone- 

 book of Nature, it may therefore be affirmed, that the period of such ex- 

 haustion in each country (for the deposits are much shallower in some 

 tracts than in others) mil, in great measure, depend on the amount of 

 population and the activity of the workmen in each locality. Anglo- 

 Saxon energy, for example, as applied in California and Australia, may 

 in a few years accomplish results which could only have been attained 

 in centuries by a scanty and lazy indigenous population; and thus the 

 present large flow of gold into Europe from such tracts, will, in my opin- 

 ion, begin to diminish within a comparatively short period. * * In conclu- 

 sion, let me express my opinion, that the fear that gold may be 

 greatly depreciated, in v.alue relatively to silver— a fear which may 

 lave seized upon the mincls of some of my readers— is unwarranted by 

 the data registered in the crust of the earth. Gold is, after all, by far 

 the most restricted— in its native distribution— of the precious metals. 

 Silver and argentiferous lead, on the contrary, expand so largely down- 

 wards into the bowels of the rocks, as to lead us to believe that they 

 must yield enormous profits to the skilful miner for ages to come; and 

 the more so in proportion as better machinery and new inventions shall 

 lesson the difficulty of subterranean mining. It may, indeed, well be 

 doubted whether the quantities of gold and silver, procurable from 

 regions unknown to our progenitors, will prove more then sufficient to 

 meet the exigencies of an enormously increased population and our 

 augmenting commerce and luxury. But this is not a theme for a 

 geologist; and I would simply say, that Providence seems to have 

 originally adiusted the relative value of these two precious metals, and 

 that their rel'ations, having remained the same for ages, will long sui-vive 

 all theories. Modern science, instead of contradicting only confirms 

 the truth of the aphorism of the patriarch Job, which thus shadowed 

 forth the downward persistence of the one and the superficial distribu- 

 tion of the other;—' Sui-ely there is a vein for the silver The earth 



hath dust of gold.,' " 



* Sihiria : or the History of the Oldest Known Rocks containing Organic 

 Remains. By Sir Koderick Impey Mm-chison. 



The Society of Arts was established at a meeting held on the 22d 

 March, 1754, at which it received the designation which it still retains 

 — " The Society for the Encouragement of Arts, Manufactures, and 

 Commerce in Great Britain." The first stone of the present building 

 was laid on the 28th March, 1772 ; the two brothers, Egbert and John 

 AnAM, from whom the Adelphi derives its name, were its architects, 

 and the Society first oocupied it in 1774. 'VVithin the period which has 

 since passed, many valuable inventions which now minister to our 

 wants and our enjoyments, ti'ace their origin to that association. — • 

 Many distinguished men owe to the opportunities it presented their 

 eminence in public life; and favourable audiences have constantly, 

 during the discussions of the Society blushed at the hesitating timidity 

 of Goldsmith, and admii-ed the profound and massive wisdom of 

 Johnson. Its objects, like its means, were at first limited, but the six 

 celebrated pictures in the Council Room, painted by Bakry between 

 the years 1777 and 1783, while highly illustrative of the state of the 

 arts at that day, enable us in some degree to contrast the advance 

 which civilization and science have since made in manufactures and 

 commerce. With the Society of Arts originated the conception of the 

 Great Exhibition of 1851 ; and in the Crysta,l Palace at Sydenham, on 

 Monday the 3d July, it celebrated its centenary by a public dinner, at 

 which nearly 800 persons were present, and over which Earl Granyillb, 

 in the absence of the Duke of Newcastle, presided. The temple which 

 then surrounded that assembly, dedicated to all the triumphs of ancient 

 and modern art, would not now excite our admiration, exalt our race, 

 and illustrate our age, were it not for the prudent and philosophic 

 efforts of the humble but long unconscious founders of the early insti- 

 tution. A century hence will find those who joined in that celebration 

 all equally silent; and it is beyond the speculative powers of the most 

 reflective mind to anticipate what fresh triumphs genius, science, and 

 art may unfold, to grace and adorn the revival of such an anniversary. 



Electro-masnetic EngraTing Blaclilne. 



This machine is somewhat on the principle of the well-known plamng 

 machine. The drawing to be copied and the plate to be engraved are 

 placed side by side, ^n the moveable table or lid of the machine ; a 

 pointer or feeler is so connected, by means of a horizontal bar, with a 

 graver, that when the bar is moved, the drawing to be copied passes 

 under the feeler, and the plate to be engraved passes in a corresponding 

 manner under the graver. It is obvious that in this condition of things, 

 a continuous line would be cut on the plate, and, a lateral motion being 

 given to the bed, a series of such lines would be cut parallel to and 

 touching each other, the feeler of course passing in a corresponding 

 maimer over the drawing. If, then, a means could be devised for 

 causing the graver to act only when the point of the feeler passed over 

 a portion of the drawing, it is clear- we should get a plate engraved, 

 line for line, with the object to be copied. This is accomplished by 

 placing the graver under the control of two electro-magnets, acting 

 alternately, the one to draw the graver from the plate, the other to 

 press it down on it. The coil enveloping one of these magnets is in 

 connexion with the feeler, which is made of metal. The drawing is 

 made on a metallic or conducting surface, with a rosined ink or some 

 other non-conducting substance. An electric current is then esta- 

 blished so that when the feeler rests on the metallic surface, it passes 

 through the coils of the magnet, and causes it to lift the graver from 

 the plate to be engraved. As soon as the feeler reaches the drawing, 

 and passes over the non-conducting ink, the current of electricity is 

 broken, and the magnet ceases to act, and by a self-acting mechanical 

 arrangement the current is at the same time divertf d through the coils 

 of the second magnet, which then acts powerfully and presses the 

 graver down. This operation being repeated until the feeler has 

 passed in parallel lines over the whole of the drawing, a plate is 

 obtained engraved to a uniform depth, with a fac-simile of the di-awing. 

 From this a type-metal cast is taken, which, being a reverse in all 

 respects of the engraved plate, is at once fitted for use as a block for 

 surface printing. The machine is the invention of Mr. William Hansen, 

 of Gotha. — Journal of the Society of Arts. 



