CIIEMICAL SCIENCE. 205 



is confirmed by the experiments of M. Anocoff, a Russian 

 engineer, published a few years since in the Annuaire des 

 Mines de liussie. He pretends to have produced blades so nearly 

 emulating those of Damascus, as to allow of their being bent 

 at a right angle, and capable of dividing a film of gauze floating 

 in the atmosphere. Mr. Henry, of England, has recently made seve- 

 ral analyses of wootz, and failed to detect in it the presence of alu- 

 mina ; he, however, found sulphur, silicon, and arsenic, in apprecia- 

 ble quantities. 



SEPARATION OF SILVER FROM OTHER METALS. 



The following is an abstract of the specification of a patent granted 

 to Alexander Parks, of England, for improvements in the separation 

 of silver from other metals. The invention consists first, of certain 

 improvements in the mode of employing zinc for the purpose of 

 separating silver from lead. Secondly, of improvements in separa- 

 ting the silver from the alloy of zinc and other metals thus produced. 

 The patentee states that he has found when lead contains 14 ozs. of 

 silver to the ton, the most suitable proportion is 1 per cent, of zinc ; 

 thus, for each ton of lead containing 14 ozs. of silver, he uses 23 Ibs. 

 4 ozs. of zinc ; for each ton of lead containing 21 ozs., 33 Ibs. 6 ozs. of 

 zinc ; and for each ton of lead containing 28 ozs. of silver, 44 Ibs. 8 

 ozs. of zinc. The process is conducted as follows : The lead, in the 

 state it is received from the sinelting-house, is melted in an iron pot, 

 and heated to the temperature of melted zinc ; the zinc, in a melted 

 state, is then added, and the whole well mixed ; the contents of the 

 pot are then stirred in the usual way, with a piece of green wood, to 

 remove any impurities ; it is then cooled ; the alloy of silver, zinc &c., 

 rises to the surface, and is removed by the means of ladles pierced 

 full of holes. A previous assay of the lead will indicate the right 

 proportion of zinc to be employed ; a larger quantity will be found 

 necessary in cases where the lead is very impure. The lead which 

 has thus been desilverised by means of zinc, often retains a small 

 portion of that metal, which has the effect of rendering it brittle : this 

 defect is remedied by the following process : 



The melted lead is run into a reverbatory furnace, and raised to a 

 dull red heat, when the zinc rises to the surface and becomes oxy- 

 dised ; the furnace is then tapped and the lead run into an iron pot, 

 when it is stirred with a piece of green wood, to remove any oxide of 

 lead which may have formed ; after which, it is ladled into moulds in 

 the usual way. By this means, 3 tons of lead may be deprived of the 

 zinc it contains in the course of from 2 to 2^ hours ; the surface of 

 metal exposed being from 25 to 30 square feet. The oxide of zinc 

 remains in the furnace, whence in may be afterwards be removed. 



In order to separate the silver from the other portions of the alloy 

 the patentee proceeds as follows : The silver is first concentrated by 

 removing as much of the lead as possible, by placing it in an iron pot, 

 the bottom of which is preforated with holes, the top being, at the 



