324 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[September, 



ance, inasmuch as all danger from collision would be obviated, and more 

 prompt assistance rendered in case of accident. Mr. Wlieatstone's proposal 

 is to have posts through which the magnetic wires can be carried up, anil 

 with an apparatus on the top placed at every quarter of a mile along the line. 

 Bjr this means the guard having with him a jiortable instrument, might com- 

 municate a message in either direction of the line at pleasure. 



IMPORTANT DISCOVERY IN METALLURGY. 



At a recent sitting of the Jcailemie des Sciences, M. Becqucrel read a paper 

 relating to a most important discovery, namely, the application of the electro- 

 chemical power to the art of metallurgy, especially as regards gold, silver, 

 copper, and lead. 



After a few preliminary remarks, explaining tlie various serrices which this 

 force can render to natural sciences, to arts and manufactures, the learned 

 academician alluded in particular to the refining of the precious metals ; and 

 it will be seen in the course of tliis analysis the great advantage he lias de- 

 rived from the uew methods introduced by him into different branches of in- 

 dustry. 



It will also be gratifjing to learn, that one of the poorest departments of 

 France possesses a gold, silver, and lead mine, and that the happy results 

 already obtained hold out a still more flattering prospect. The following is 

 an analysis of the memoir presented by M. Becquerel: — 



The experiments relative to the application of the electro-chemical power 

 to refining (metaUitryieJ of silver, cojiper, and lead, without the aid of quick- 

 silver, and with little or no fuel, have been continued by M. Becqucrel with 

 constant success : his operations were conducted upon a large scale, and em- 

 braced considerable quantities of ores derived from Europe, Asia, and America. 

 The object of these researches was in the first place the immediate separation 

 (redtictionj of the metals one from the other, and especially of silver and of 

 lead from galena ; this operation was effected with so much rapidity, that at 

 the preparatory foundry in Paris four pounds weight of silver can now be 

 drawn off in the metalled state from silver ore in the space of six hours ; se- 

 condly, the preparation which the ore is to undergo, so as to render each 

 metal capable of being withdrawn by the electric cuiTent. This preparation 

 varies according to the nature of the ore, presents no obstacle when tlie silver 

 is in the metallic state, or in the nature of a sulphate, as usually occurs in 

 Mexico and Peru, but it becomes more complicated when the silver is mixed 

 with other substances ; the use of a small qiiantity of combustible matter is 

 then indispensable in order to effect the roasting at a low temperature. 



Ores are generally found in great quantities in those countries, but are for 

 the most part abandoned, owing to the want of sufficient fuel for effecting 

 their amalgamation, or to their being found at too great a distance from the 

 sea to transport them to Europe, unless at an enormous expense. 



In Columbia, where large masses of gold and silver ore are found mixed 

 with zinc, the richest are sometimes exported to Europe to be fused, whilst 

 the poorest and those of a medium quality are either rejected altogether, or 

 used to so little advantage, that the mining companies lose by them. Exer- 

 tions are now in progress for introducing the new methods, which are equally 

 applicable to amalgamation and to the electro-chemical process. 



The silver ores which are most difficult of amalgamation are those which 

 contain a large portion of copper and arsenic. Ores of this description are 

 found in considerable quantity, especially in Cliili, where the inhabitants fre- 

 quently offer them to Europeans, by whom they are sometimes taken for 

 ballast for want of freight, and without any certainty of turning them to ad- 

 vantage. 



The great difficulty was to be able to treat these substances in Europe so 

 as to obtain, in separate portions, and at little expense, all the silver, copper, 

 and arsenic they contained. This problem has just been solved in a satis- 

 factory manner, and so as to ensure immense advantages to new speculators, 

 w^ho will no longer have to contend with the obstacles met with by their 

 predecessors. 



On inquiring into the causes of the delay experienced in working the mines 

 in America, it will be seen that the principal ones arise from the high price of 

 quicksilver, and the great difficulty of draining the water by which the mines 

 are inundated. This is not the case in Asia, in the Russian possessions, 

 which are rich in mineral productions, and \-ield larger profits from day to 

 day in consequence of the introduction of the improvements lately adopted 

 in Europe for reducing metalUc ores. In the silver mines of Altaic the ex- 

 penses for extracting the ore, process of reduction, and of the estabUshment, 

 do not amount to a quarter of the rough produce, Jilthough the ore in general 

 is of slight tenacity. These advantages are owing to the modern price of 

 labour, the abundant supply of combustible matter and substances required 

 in the fusing, and which are not to be had in America, especially in Mexico 

 and the Cordilleras. 



The electro-chemical process can be easily applied to the ores at Altaie ; 

 however, in countries where sufficient fuel is at hand, and salt cannot be 

 procured, the fusing operation will be always preferred, except in cases of 

 complex ores, which often exercise the ingenuity of metallurgists. 



There are but few silver mines worked in Russia. The only ones of im- 

 portance are those of Altaie, Nertchinsk, and those of the Caucasus and the 

 Ural ; but the great source of mineral riches in that kingdom consist princi- 

 pally of the gold and platina dust (sands), the wasliing of which engrosses 

 th« chief attention of the Government. This process, though methodically 



conducted, is very imperfect, for a large quantity of the gold contained ia 

 the sand is lost ; the proceeds, however, are considerable; during the last 

 year no less than 12,200H>. were obtained, upwards of 800,000/. value. 



The argentiferous and auriferous galenje which have been subjected to the 

 electro-chemical process are perfectly lit for tlie extraction of golil aud silver 

 by washing. This method requires that the ores should be pulverized and 

 roasted so as to separate the metal from the pyrites and other compounds 

 which detain it. The silver and lead being removed, the ore thus reduced 

 to about half its weight, can be washed with the greatest facility, and one 

 man can wash several hundred pounds i)cr day. This method was tried mth 

 the galena (very argentiferous) discovered a few years since at St. Santia 

 Cantales, in the department of Cantal, and which yielded not more than 

 2', grains of gold in every 2001b. of ore, with 30 per cent, of lead. But, upon 

 adopting the electro-chemical i)rot:ess, the same qu,intity of ore produced 

 something more tlian three draclims of gold. From this important result it 

 is supposed that the rocks in that part of the country arc amilerous, as might 

 also be inferred fiom the name of the place, Aurilac (imri lacus). Another 

 great advantage of the elect ro-chymical method is, that it enables the metal- 

 lurgist to separate those portions of ore which contain gold, silver, &c., from 

 those which contain none. 



M. Becqucrel then alluded to the other uses to which electricity might be 

 applied in the manufacture of metals, especially in the art of gilding silver 

 and copper, as also for taking impressions in copper of medals, bassi relievi, 

 and engravings. 



The learned academician concluded by observing that this new and highly 

 important power was only in its infancy, and that it would be impossible to 

 foresee the immense services it was likelv to render to the arts. 



GRANTON PIER. 



There are, perhaps, few engineering works at present in progress in Scot- 

 land that seems to attract more general interest than the magnificent pier, 

 now in course of being erected, by His Grace the Duke of Buccleugh, on His 

 Grace's property at Granton, a few miles northward from the city of Edin- 

 burgh. 



The original object and design for a new pier at Granton, was to supply 

 the wants of the city of Edinburgh in regard to steam-vessel conveyances, 

 that passengers might there embark and disembark with safety, in all states 

 of the tide and weather, without boating — the inconvenience arising from the 

 want of which, both from there not being found a proper site, and the requi- 

 site funds for accomplishing so truly desirable an object elsewhere, has been 

 but too long felt and acknowledged in that quarter. Accordingly Mr. Walker 

 of London, that most talented and deseivedly celebrated ciril engineer, was 

 sent for in the year 1836; and after examining the coast adjacent to the 

 Scottish capital, without any restrictions as to locality, he pitched upon 

 Grautou as being the most eligible site for such a work ; and having prepared 

 suitable working plans, this great and useful work was forthwith commenced, 

 and has since been unremittingly carried on at the sole expense of a single . 

 indi\-idual — that' distinguished, patriotic, and benevolent nobleman the Duke 

 of Buccleuch. 



A brief descrijition of the general plan of the pier may not prove uninte- 

 resting herfe. Granton Pier commences at high water mark on the shore, 

 and runs at right angles with it iiito the Frith of Forth ; it is intended to be 

 about 1,700 feet in length, by about 150 feet in breadth; is to be built 

 chiefly with stone, and founded upon shale rock ; it will be so arranged as 

 that it will have a double roadway and front wall, one on either side, with a 

 parapet wall in the centre (with connecting openings between the sides), on 

 each side of which will be a footpath. The sea or front walls will be exactly 

 alike, and so divided that there will be six jetties, and one slip or inclined 

 plane on each side of the pier, and one jetty at its outer end ; these jetties 

 will be each strongly faced with timber, ancl so ingeniously contrived and put 

 together that a platform of planking will be on its top, and an intermediate 

 one below, which will communicate with the roadway by means of an easy 

 stone staii'. Each jetty will have two cranes on an improved jirinciple, one 

 at each end, and a double warehouse, in the centre of which the aforesaid 

 stair passes ; the jib of each crane will swing right into one of the doors of 

 each warehouse, and obove the liatchways of vessels lying at jetty. The slips 

 or inclined planes are faced with wooden defenders, so that vessels landing 

 live stock, &c., may haul up or down as the state of the tide may be. The 

 depth of water on both sides of the pier, with the lowest spring ebbs, will 

 be twelve feet at low water at the outer end, diminishing very gradually in- 

 ward ; and the bottom is of a soft and fine clay. It is intended that the pier 

 shall have an elegant approach, and a lighthouse at its extremity. 



From the principle on which Granton Pier has been carried on, namely, 

 finishing as it goes outwaril, it has already proved itself to answer better than 

 was anticipated, not only as a place where steamers of the largest size can 

 dash in and out with the lowest ebbs, where the passenger can by a few safe 

 and simple paces step from the steamer into the cab, and drive off at full 

 speed, and vice versa, but as a place of accommodation and refuge to all 

 classes of vessels, in all kinds of weather. As a pier from which steamers 

 can arrive and depart with ease at their respective fixed hours, it has already 

 been fairly proved without failure ; as a place for despatch, it may be mentioned 

 that one of the large London steamers lately arrived heavily laden — she was 

 unladen and laden again, she disembarked and embarked her passengers, and 



