228 ANNUAL OP SCIENTIFIC DISCOVERY. 



uniform brown color. The sulphate and chloride of manganese being exten- 

 sively used in dyeing, calico-printing, and other arts, and in making the com- 

 pounds of manganese, the simple means stated of forming those salts, free 

 from iron (it is presumed), are material improvements on the circuitous meth- 

 ods hitherto adopted. 



ON THE MANUFACTUKE OF STEEL. 



In a recent communication to the Boston Society of Natural History, on 

 the manufacture of steel, Dr. C. Y. Jackson stated, that when iron is mingled 

 with a considerable proportion of manganese, a brittle compound results ; but 

 when combined with a very small proportion of manganese, a steel of very fine 

 quality is obtained, which has this advantage over carbon steel : carbon steel 

 becomes coarse when tempered in thick masses, from segregation of the par- 

 ticles of carbon, but no such trouble arises with manganesian steel. Parties 

 in England have lately introduced excellent wire for piano-forte strings, made 

 of this kind of steel, as well as for cutting instruments and other purposes. 

 In the wire Dr. Jackson has found 1-12 per cent, of manganese, and has es- 

 tablished the fact that it resists, to a very remarkable degree, the action of 

 hydrochloric acid. Sixteen years since Franklinite iron was manufactured by 

 Mr. Osborn into very hard and fine steel. This steel required tempering at 

 a lower heat than carbon steel. Many of our manganesian irons might be 

 manufactured into steel by the simple process of fusion, and a steel of uniform 

 character might be made without previous" cementation with carbon. Man- 

 ganesian iron ore is reduced to pure iron, or " comes to nature," in the lan- 

 guage of the workmen, with much greater rapidity than carbon iron ; hence 

 the two metals are often mixed to " come to nature" at a good time, requiring 

 less care and watchfulness on the part of the workmen. Manganesian iron 

 makes the best bar iron. 



BUNDLE'S METHOD OF SEPARATING GOLD. 



In a letter to the London Mining Journal, J. H. Bundle of the Colonial 

 Gold Works, at Rotherhithe, states that mercury, in the separation of gold 

 from auriferous sands, unites with it in varying quantities. The quantity of 

 gold absorbed by mercury depends, he says, on the following conditions: 

 first, the more or less finely divided state of gold in the ore; second, the 

 length of time during which the mercury remains in contact with it ; third, 

 the temperature at which the amalgamation is conducted ; fourth, the pres- 

 ence of other metals in the amalgam. 



The following method of separating gold from mercury, when the latter by 

 assay is found too rich, is employed : The mercury, after being strained, is 

 assayed ; granulated zinc, previously cleaned with dilute sulphuric acid, is then 

 added to it. As soon as the zinc is completely amalgamated, which takes 

 place in a few hours, the mercury is well stirred and restrained; a solid 

 amalgam is obtained, containing, practically speaking, the whole of the gold, 

 and the greater part of the zinc which has been added. The proportion of 



