318 DESCRIPTION OF THE TIN VEINS , 



are sullicicntly hard to scratch phosphate of lime, but not quite 

 so hard as adularia. Specific gravity of the compact ore, contain- 

 ing a few particles of quai-tz, 6.4'^ to 6.487. The compact ore 

 is found investing tlie walls of the veins, and the smallest ones 

 have a thin layer of quartz running through the centre, in which 

 are implanted numerous brilliant crystals of the oxide of tin, 

 which are remarkably perfect. Before the blowpipe alone, this 

 ore is infusible ; nor does it dissolve in glass of borax, or in bi- 

 phosphate of soda. It is insoluble in acids. Pulverized and 

 mixed with powdered charcoal, with two thirds carbonate of soda 

 and one third glass of borax, it is readily reduced on charcoal to 

 metallic tin, which may be thus separated in brilliant globules, or 

 in a small button. 



These globules, when acted upon by nitric acid, are converted 

 into insoluble stannic acid, which is of a white color, and is also 

 insoluble in acids. It was evident, when a fragment of the tin 

 ore was reduced to the metallic state, that the metal w^as nearly 

 equal to three fourths of the Ijulk of the ore reduced. 



On pulverizing and washing a quantity of the vein stone con- 

 taining crystals and grains of the oxide of tin, a heavy ore was 

 obtained, containing a few particles of the arsenical pyrites 

 and a little copper ore, which, on being roasted, to free it from 

 arsenic, and reduced, yielded, according to the purity of the 

 specimen, from thirty to fifty per cent, of tin. A selected speci- 

 men of the compact oxide, reduced to the metallic state, yielded 

 seventy-three per cent, of tin, which was perfectly pure. 



An average lot of the fragments of ore taken from the small veins, 

 when reduced, yielded sixty-four per cent, of metal, which was 

 impm-e, but on being refined gave fifty-four per cent, of pure tin. 



Five ounces of the pulverized ore was taken for reduction. It 

 was first boiled wdth a little nitric acid, to remove the soluble 

 oxides and impurities, and then reduced in a crucible lined with 

 lampblack, at a forge heat, and yielded three ounces of pure tin, 

 which was cast into an ingot. This is the specimen now laid 

 before the Association. A piece of the ingot was cut off and 

 rolled out into a sheet, which was also exhibited. This specimen 

 is, in fact, the first ingot of tin that has been extracted from an ore 

 found in this country. 



