Trans. N. V. Ac. Sa. 4 Oct. ij. 



He stated to the Academy that since its adjournment in June he had 

 made the discovery of tellurium in certain copper products from 

 Colorado. The sample examined had been found to work unsatisfac- 

 torily and was supposed to contain arsenic and antimony, as the pig 

 yielded dense white fumes in the furnace. After a careful examination no 

 arsenic nor antimony was found, but nearly one half per cent of tellurium. 

 The fumes poisoned the furnace, and the copper manufactured cracked 

 in the rolls, was useless except for brass of poor quality, but was quite 

 suitable for the manufacture of cupric sulphate. A number of ounces to 

 the ton of silver and gold were found in the same copper, but too little 

 to make a metallurgical separation possible. 



Dr. Egleston also announced that after making a long series of exam- 

 inations on the presence of silver in Lake and other brands of' commer- 

 cial copper, he had come to the conclusion that the silver was very un- 

 equally distributed in it ; as assays taken fifteen minutes apart from 

 several different charges, during the last two hours of the process while 

 ladling, show the quantity to vary as much as eight or ten ounces in the 

 different assays. 



Dr. J. S. Newberry remarked on : 



GEOLOGICAL FACTS RECENTLY OBSERVED IN MONTANA, IDAHO, 



UTAH AND COLORADO. 



Idaho and Montana. — The famous placers at Helena and Virginia, 

 which have yielded thirty millions of dollars, are now exhausted, but 

 vein-mining is in successful progress and yielding rich results at Butte, 

 at the Alice, Lexington, Copper Bell, and other mines. These are true 

 fissure v^eins, traversing a granite formation, and the speaker predicted 

 their abundant yield of silver and copper twenty years hence. These 

 territories have been simply crossed by two government expeditions 

 and their resources have not been at all studied. It is the coming min- 

 ing region, more discoveries of promising mines having been recently 

 made here than in any other portion of the country. On the east of 

 the mountains in Montana and "Wyoming lies a fine agricultural coun- 

 try and excellent stock range, the herds ranging freely throughout the 

 winters, in spite of their severity, with little loss, and grazing upon a 

 native bunch-grass {Feshtca scabrella) and the buffalo grass {Buchloe 

 dactyloides). The climate is salubrious, the country very beautiful in 

 many parts and very promising for emigration. In the adjacent Rocky 

 Mountains range there are also many mining opportunities. 



The remarkable lava plain, 400 miles long by 75 miles wide, in Cen- 

 tral Idaho, was then described. Snake River, one of the chief tributaries 

 of the Columbia, flows along its southern border for several hundred 

 miles ; its northern tributaries sinking under the lava sheet and flowing 

 in subterranean channels 50 or 60 miles long. The rock is a basalt said 



