May 22. 1885.1 



SCIENCE 



419 



gold? 4. Will there be much waste in treat- 

 ing the ore? 5. If so, how much, and what 

 means should be adopted to avoid it? 



The rock was crushed fine in a stamp-mill, 

 and the fine sand was conducted by the agency 

 of water over a series of amalgamated copper 

 plates, by which any active or free-milling gold 

 was taken up, and the passive, rusty, included 

 gold was allowed to pass on, together with the 

 sand. This sand, before going to waste, was 

 treated on a concentrator ; and from the 

 product or concentrate the greater part of 

 escaped gold could have been extracted by 

 chlorine. 



The yield of gold per ton was as follows : — 





Nova-Scotia 



New 



-Hampshire 





ore. 





ore. 





Coarse nuggets. 



Very fine grains. 



Gold in the amalgam of th< 









stamp-mill 



$13,040 





$2.28 



Gold on the first plate . . 



0.200 





1.35 



Gold on the second plate . 



0.010 





0.11 



Gold on the third plate . . 



0.030 





0.09 



Gold on the fourth plate . 



0.007 





0.05 



Gold on the fifth plate . . 



0.002 





0.03 



Gold in the concentrates . 



0.150 





0.37 



Gold on the additional mer 









cury trap 



- 





0.02 



From these experiments the students ascer- 

 tained that the Nova-Scotia gold is very coarse, 

 is almost all saved in the stamp-mill, and less 



S .,*=* 



A, furnace-room; B, assay-room; C, milling-room; D, sup- 

 ply-room; E, toilet-room; F, private laboratory; G, office; 

 H, balance-room; I, vaults; J, entrance to vaults. 



than five plates will answer for treatment, and 

 that the concentrates yield very little additional 

 gold ; while New-Hampshire gold is quite fine, 

 is not much more than half saved in the stamp- 

 mill, that five plates are not enough, and if 

 the series were continued to eight or ten the 

 last would probably more than pay for itself, 

 and that considerable gold is saved in the con- 

 centrates. 



A third student had a lot of galena weigh- 

 ing one ton to treat for lead, silver, and gold. 

 Aided by his classmates, he crushed the ore, 

 sampled, calcined, sintered, and smelted it, 

 obtaining base bullion He extracted the gold 

 and silver by the zinc process, followed by 

 cupellation. The silver-gold brick obtained 

 was carefully valued, as were also all his prod- 

 ucts throughout the test. The losses in the 

 process were, — 



In calcining 



In smelting 



In cupelling 



Per cent. 

 Lead, 5. 

 Lead, 12. 

 Lead, 8. 



Per cent. Per cent. 

 Silver, 2. Gold, 0. 

 Silver, 7. Gold, 4. 

 Silver, 6. Gold, 1. 



Total losses .... 



Lead, 25. 



Silver, 15. 



Gold, 5. 



From the results, not only did he learn with his 

 own hands and eyes where the greatest dif- 

 ficulties are to be encountered in lead and 

 silver smelting, but also the familiarity with 

 this process rendered his reading upon the 

 smelting of copper, iron, and other metals, far 

 more intelligible and real. 



When work by day only is called for, there 

 is enough of the spirit of investigation in 

 nearly every student to carry him over the 

 tedious part of his task for the sake of the 

 results he sees immediately within reach. 

 When the test lasts through the night also, as 

 happens three or four times during the year, 

 there is always enough of the savor of camping 

 out to help keep up the interest. 



SILVER FROM A PENNSYLVANIA 

 MOUND. 



Situated near the town of Irvine, Warren 

 county, Penn., on a very pretty and fer- 

 tile bottom of the Alleghan} T valley, are two 

 mounds, well known for the last seventy years. 

 No opening had been made in either in this 

 time, except a shallow pit dug in the side of 

 the smaller about fifty years ago. While 

 spending a few days last summer in that re- 

 gion, I obtained permission of the very intel- 

 ligent and courteous owner, Dr. William A. 

 Irvine, to make a thorough exploration of 

 them. 



The smaller, which is on the bank of the 

 river, near the point where it is joined by the 

 Broken straw Creek, is circular, fifty- two feet 

 in diameter, and three feet and a half high, 

 but has evidently been considerably lowered 

 and expanded by the plough, as the land has 

 been under cultivation for at least sixtv years, 



