169 



Hab. Para Elver. 



These two forms, with others, will be figured at the earliest oppor- 

 tunity. 



Dr. A. A. Hayes presented some S|3ecimens of ores, inter- 

 esting in a scientific and economic point of view, with the 

 following remarks : — 



Mr. President: In calling the attention of the Society to the 

 specimens before me, I am aware that the remarks I shall make be- 

 long to a Technological Institute, rather than to a Natural History 

 Society. But as there are some points of a truly scientific character, 

 involved in the descriptions, I have thought that my excuse, if neces- 

 sary, might rest on these. 



A specimen of brown hydrate of iron, from the Sierra Nevada 

 Region, containing gold. 



2,000 lbs. of this ore aflTord '^yqo'q ^^- ^^ g<^^^- The usual meas- 

 ure of such ore, used by the miners, is the cubic cord, or 128 cubic 

 feet, and the yield of gold is there calculated on the cord of ore, 

 which is very abundant. 



Having made numerous analyses of iron ores, difiering in no 

 respect physically from this ore, the question has often arisen in my 

 mind, why one specimen in a thousand should contain gold, and the 

 remainder not any. 



We do not answer this question fully when we say that the 

 pjT-itous ore from which it was derived was in one case auriferous, 

 and in the other not so, for it appears from the most extended obser- 

 vations, that gold belongs to the minerals of certain localities, and is 

 not found in the same minerals in other localities. 



Argentiferous Galena in its gangue rock, from the vicinity of Pike's 

 Peak. In a region as yet but little explored, this rock occurs con- 

 taining galena, blende, pyrites, and oxide of manganese. The lead 

 contained in 2,000 lbs. weighs 860 lbs. and this quantity of lead 

 affords '^'^^io ^^- ^^ silver. 



By stamping and washing the ore, a more concentrated product 

 would be obtained, and a further step in the way of reduction on the 

 spot would enable the miners to throw into the market a great quan- 

 tity of rich silver lead, bearing the charges of transportation and 

 cost, besides yielding a profit to the miner. 



Antimonial Galena with silver from Sonora. 



This ore is here presented in its marketable form, and the specimen 

 is part of a shipment, which was assayed by myself. 2,000 lbs. of 

 this ore afforded 1,228 lbs. of lead. This portion of lead was so rich 

 in silver that ^'^j-^^q pounds of silver were contained in it ; or the 

 silver in a ton of the ore has a value of about six hundred and sixty 

 dollars. 



