1835.] 



Improvements in Science. 



211 



96 lbs. Troy.) Gold produced by the different workings 

 is assayed in the mints of Katharinenburg, and St. Peters- 

 burg. 



The following table exhibits the composition of gold from 

 different localities, all being richer than gold from Colombia 

 and Siebenburg : — 



Katharinenburg 

 Hiel. . . . 

 Miask . . . 

 Bogowslowsk 

 Kuschwa . . 

 Werch Isetsk 

 Nischne Tagil 

 Kaslinski . 

 Newiansk . . 

 Do. . . . 

 Sisersk . . . 

 Ufaley . . . 

 Schaitansk 

 Bilimbajeusk . 



Bewdinski . . 

 Usewoledski . 

 Bissersk . . 



Before the blowpipe, pure gold and pure silver are readily 

 distinguished by their fusing into a transparent and colour- 

 less glass, with salt of phosphorus in the exterior flame. 

 In the interior flame, if the quantity of silver is small, the 

 glass is opaline and yellowish, but if great, altogether 

 yellow and opaque. The native alloys act in the same 

 manner, but an alloy which contains only £ per cent, of 

 silver has no action on salt of phosphorus. 



When the quantity of silver is small, which can be easily 

 detected by the golden colour of the alloy, the metals may 

 be dissolved in a covered capsule, in aqua regia. The greatest 

 portion is converted into chloride of silver. Decant the 

 solution and remove the chloride by the aid of a glass rod, 

 and add a new dose of acid. If the alloy contains more than 

 20 per cent, of silver, the chloride sticks to the glass, and 

 gives rise to inaccuracy. The two acid solutions should then 

 be diluted. The first is only slightly muddy ; for, it appears 



