706 A. C. LAKE GEOTHERMS OF LAKE SUPERIOR COPPER COUNTRY 



Degrees 

 Fahrenheit 



The hottest and deepest reading was in the bottom of the Tamarack, at 



(5,367)' feet 91.4 



A more reliable record is by C. P]. Van Orstrand, on the 81st level of 

 the Calumet and Hecla (checked by myself in August, 1922, as 86 



degrees centigrade) , at 4,900 feet 86.4 



I also found at the 78th level (about 4,700 feet from surface) 84 



at the 74th level, about 4,480 feet 82 



at the 22d level, Ahmeek (1,870 feet), short drill-hole 65.4 



level, Ahmeek, dirt on floor 62 . 3 



Isle Royale No. 5 shaft, 21st level (2,664 feet) about 66 



19th level (2,425 feet) 63 



Champion No. 4 shaft, 8th level 51 



17th level warmed by mine circulation, probably, compare — 54 

 Observation in 1909 on the 13th level, when the mine was 



newer 52 . 1 



Arcadian Consolidated (New Baltic shaft), 1,100-foot 



level — that is, about (900 feet down) 58 



The more reliable® observations are^ however — 



Tamarack 5 (4,662) feet 82 



Quincy (3,875 feet) ± (S. Smillie) 76 



(3,856 feet) 74 



( 3,246 feet ) 69 



(1,130 feet) 52 



C. J. McKie reports the temperature of water flowing from a drill-hole 

 in the Baltic Mine of the Copper Range Company, 36th level (3,277 

 feet), 71 degrees. On the 3,950-foot level, 1,200 feet from the shaft, 

 rock and air temperature (3,599 feet), 74 degrees. J. AY. Alt, chief 

 engineer of the Montreal Mine, Hurley, Wisconsin, reports the tempera- 

 ture of a drift at the bottom of that mine (1,676 feet down) as 19 degrees 

 to 1914 degrees centigrade, and of water flowing from a drill-hole, 70 

 gallons a minute, as also I914 degrees centigrade, equal to 67 degrees 

 Fahrenheit. 



The following table, for which we have to thank the Bureau of Mines 

 and Mr. T. Dengler, the agent of the Mohawk Mine, shows not only the 

 temperature at various depths, but by the dates, which may also be useful 

 hereafter, something of the error to be expected in observations owing to 

 ventilation, circulation, and variation of temperature in the air between 

 winter (February) and summer (August). The dip of the mine varies 



^ Numbers in parentheses are vertical depths from the surface, supposed to be flat. 



® The depths given by the engineer are below Lake Superioi*. To this Darton adds 

 500 feet and I here 550, and I have changed my views as to the more reliable observ-a- 

 tions. Crosscuts are better sometimes than short drill-holes, farther from ventilation, 

 less affected by boring. 



