252 



GEOLOGY OF THE COMSTOUK LODE. 



Table III.— FORMAN SHAFT. ROCK 

 TEMPERATURES. 



[From 100 to 1,800 feet.) 

 o = 49.8. 6 = 0.0326 ± 0.0006. 



Table IV.— FORMAN SHAFT. ROCK 

 TEMPERATURES. 



[From 500 to 2,300 feet.) 

 o = 53.2. 6=0.0296 + 0.0002. 



' Probable enor of an obseTvation = ± 1°.3. 



rof an observatio 



Table V.— FORMAN SHAFT. WATER TEMPERATURES. 

 o=45.8. 6=0.0373 ±0.0010. 



^Probable error ot an observation = ±1°.3. 

 These temperatnres were ascertained by drilling holes not less than three feet deep into the rock and inserting a Ne- 

 gretti A Zambra slow-acting thermonK'ter (of the pattern adopted by the Underground Temperature Conimittee of the 

 British Association and standardized at Kew)into the hole, closing the hole wiih clay, and leaving the thermometer for from 

 12 to 24 hours. Not less than three holes were tried at each point. 



