4o0 Intelligence and Miscellaneous Articles. 



fchese mountain chains, we have first granite ; and this is flanked by 

 Subcarboniferous limestone, in most places so crystalline as to 

 obliterate all traces of fossils. Protruding through these, and 

 forming the mountain-peaks, we have porphyry, quartzites, basalt, 

 diorites, and trachytes. 



The country rock in the immediate vicinity of the antimony- 

 mines is quartzite and limestone. The lodes are from four to 

 twenty feet wide; and exploitation work, carried to a depth of 

 thirty feet, shows that the fissures are filled from wall to wall with 

 the oxide of antimony, almost pure and remarkably uuiform in 

 character. The course of the lodes is nearly north and south ; 

 the pitch is high to the east. The area over which the ore is found 

 may be roughly stated to be five or six miles long and half a mile 

 or more wide. 



The Boston Company controls nine mines, each of which is a 

 full Mexican claim, 800 metres (2624 feet 8 inches) long and 200 

 metres (656 feet 2 inches) wide. On three of the mines the crop, 

 which is solid oxide of antimony, stands up boldly above the 

 general surface, and may be traced along the claims for many 

 hundred feet. As stated above, the ore, so far as explorations 

 have exposed it, is almost pure oxide of antimony, the little 

 impurity it contains being silica. The fire assays show it to contain 

 from 60 per cent, to 70 per cent, of pure metal; and I have 

 estimated the entire lode to average 50 per cent. By selection the 

 average may be augmented. On going down to a greater depth in 

 the lode, it is possible that the oxides may give place to sulphides ; 

 but thus far there is not the slightest evidence of any change. 



This discovery is destined to produce a marked influence upon 

 the production of metallic antimony, and to greatly extend its uses. 



Prof. S. P. Sharpies, of Boston, after an examination of many 

 specimens of the oxide of antimony received from me, has made 

 the following statement: — " The mineral varies in colour from almost 

 white to a very dark brown. The specific gravity of one of the 

 purest specimens is 5*07 ; and it contained 5 per cent, of water, and 

 75 per cent, of antimony. This composition and specific gravity 

 approach very closely the same for stibiconite. 



"The mineral is only very slightly soluble in hydrochloric or 

 nitric acid, or aqua regia. Fusion with bisulphate of soda only 

 partially resolves it. It is, however, readily and easily decomposed 

 in a platinum crucible with carbonate of soda. 



" This oxide of antimony has hitherto been found only as a 

 slight coating on other antimony minerals ; and it has been difficult 

 to get specimens of it even a few grains in weight. 



" The mineral is not easily reduced before the blowpipe, but is 

 very easily reduced in a crucible with powdered charcoal or cyanide 

 of potassium, giving at a single operation buttons of star anti- 

 mony." — American Journal of Science, November 1880. 



ON THE THERMOELECTRIC ROWER OF IRON AND PLATINUM IN 

 VACUO. BY PROF. C. A. YOUNG, OF PRINCETON, N. J. 



Exner, a few months ago, published a paper asserting that the 



