322 TIN VEINS OF JACKSON, N. II. 



cent. About two per cent, of the xinc was lost by adhesion to the 

 neck of the retort, and we may reckon the yield of the ore in the 

 large way at forty per cent. 



Two thousand gi-ains of the black blende of Warren yielded 

 by the same operations four hundred grains of pure distilled zinc, 

 or twenty per cent. In the large way it would give from t\vcnty- 

 five to thirty per cent, of the metal. 



I exhibited to the Association specimens of the ores here men- 

 tioned, with the metals extracted from them. 



Assay of the Galena of Siielburne, N. H. 



Two thousand gi'ains of the galena yielded fifteen hundred 

 and fifty-eight grains of lead, or 77.8 per cent. The lead cupel- 

 led gave 2.5 grains of pure silver, or two and a half pounds to the 

 ton of ore. 



The galena of Eaton also contains sufficient proportion of 

 silver to repay the expense of extracting it from the lead. It 

 contains eighty-four per cent, of lead, and a ton of the lead will 

 yield two pounds of silver. 



Provided the zinc and lead ores are both wrought, it might 

 prove profitable to renew operations at these mines. 



At Warren, copper pyrites of great purity occurs, associated 

 with tremolite rock, the ore yielding, when pure, thirty-two per 

 cent- of copper, by assay. If the copper ores are wrought, it will 

 be easy to manufacture brass from this copper, and the oxide of 

 zinc prepared from the blende occurring near the copper vein. 

 Researches are now going on to ascertain whether the copper 

 vein becomes richer and more solid as it descends into the rock. 



