722 



GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



To complete this examination the powder and metallic grains of vesicular speiss 

 No. 5 were tried separately, with the following results: 



Discussion. — It Las been seen that types No. 1 and No. 2 contain sensibly the same 

 amonnt of precious metals, but why type No. 3 should contain such a large quantity 

 of silver as 40 ounces the writer is not prepared to explain. The fact that the silver 

 is contained, not in the metallic grains, as might have been supposed, but in the speiss 

 itself, renders the e.x])lanatiou more difficult yet. 



Speiss No. 2 (type No. l),from Messrs. Billing & Eilers's smelter, was made in 

 connection with dolomitic slag. The difference in the contents of silver is very large, 

 and is probably due to a corresponding diiference in the assay of the bnlliou extracted 

 at the same time. 



IRON sows OR SALAMA^•DERS. 



The sows, or small masses of reduced metallic iron, which are formed occasion- 

 ally in the blast furnaces, on being analyzed prove to be a variety of speiss. The 

 writer expected some important results from their examination, for the reason that 

 metallic iron reduced in the blast-furnaces becomes the center of the most important 

 chemical reactions, and that here was an opportunity of observing the various com 

 ponents of the smelting charges in the verj- act of combination. 



The sample submitted to analysis was prepared from a great variety of speci- 

 mens — two from the Little Chief, three from Gage, Hagaman & Co., and four from the 

 California smelter. 



The specimens from the California smelter were taken from three sows of very 

 tough metal, and measuring 1 foot G inches by 10 inches by 1 foot, and also 1 foot C 

 iuclies by 10 inches by 5 inches. One of tbese sows was impregnated with the peculiar 

 slag which has been describe<l under the name of scoria. One of the specimens of 

 reduced iron was extracted in small bits from the very midst of a slag, where it was 

 found side by side with small bits of speiss, which were perfectly fused, but which bad 

 not had time to collect together. A similar specimen was extracted from a slag found 

 at the Little Chief smelter. All the specimens of sows were full of large cavities, tilled 

 with charcoal, coke, slag, scoria, and regular speiss. The sample analyzed was pre- 

 pared by pounding bits detached from the sows until no dust could be obtained, so 

 that it is the toughest portion of the sows that has been analyzed. The metal forming 

 the sows is sometimes rather brittle, but is also often very tough. Tough or brittle, 

 however, when broken it exhibits a decidedly crystalline structure, the crystals being 

 almost large enough to be measured, and the metal itself is perfectly white and bright. 



