898 TEAySACTIO.\S OF THE A M ERIC AX LXSTITUTE. 



polarized, is, therefore, not reflected light, but self-lumiiioiis. This 

 is, however, only a proof of what it is not. A proof of what it is, and 

 which makes its identity with the well known silent electric dis- 

 charges in vacuo very probable, is, that it always proceeds from the 

 magnetic pole ; that the luminous beams passing high over our heads, 

 from north to south, act on the compass needle, giving it an intermit- 

 tent easterly or westerly deviation, exactly like an electric current 

 would do after the law discovered by Oersted ; and also that it induces 

 such strong currents in telegraph wires that usually during the pre- 

 valence of an aurora, the electric telegraphs are worked by it, with- 

 out batteries, which is another phenomenon perfectly in accordance 

 with the laws of electric induction. 



It is true that auroras occasionally do not aifect the telegraph wire, 

 but this is exceptional ; they always aifect the compass needle. This 

 little instrument even indicates a coming aui'oral display, when dur- 

 ing the day-time the currents are still invisible. Sometimes the aurora 

 borealis has been seen during the day-time projecting its beams from 

 the north while the sun was above the horizon ; observations well 

 authenticated. 



Di". Louis Feuchtwanger presented the following paper: 



On Gold Mines. 

 The discoveries of gold in California, Australia and Xova Scotia 

 have brought to light many important facts in the highest degree 

 •cheering for the welfare of the world ; for experience has shown that 

 mines which have been worked for the last twenty years have 

 increased in richness many fold, and continue to with deeper work- 

 ings. ■ The oldest mine is Amadar ; the North Star, the Albion, the 

 Eureka and Hay wards, are giving daily proofs ; the latter, at a depth 

 of 1,250 feet, is yielding the gold bearing quartz, and bringing the 

 proprietor a daily income of ^1,500, while the same mines at upper 

 levels brought him to ruin ; an assertion given by him to the writer a 

 few years ago, on the journey from San Francisco. The Grass 

 Valley mines, such as the Allison Ranch, particularly the Eureka, 

 have increased in value from twelve dollars a ton to seventy dollars 

 per ton, the latter being now 300 feet in depth. Nova Scotia 

 furnished in 1862 but 7,275 ounces of fine gold, has, according to 

 official reports, yielded in 1867, 27,290 ounces pure gold. Another 

 important fact, the scientific miner has found that the widest auri- 

 .ferous veins are not usually the richest, and that some of the laminte 



