Bulletin Volume 701

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 edition. Excerpt: ...on Keweenaw Point, Mich. a The figures in this column were used in calculating the rates of increase. Wheeler states that the most satisfactory results were obtained in the Atlantic mine, where observations at intermediate stations gave an accordant rate. The Conglomerate mine is 36 miles farther east. The rate in the Tamarack mine may be vitiated by the proximity of active mining. All the mines were nearly dry. Wheeler suggests that the low rate of increase in this district may be due to the proximity of Lake Superior, with its great volume of cool water (38. 8). Temperature observations in mines and holes in northern peninsula of Michigan, a a Lane, A. C, The geothermal gradient in Michigan: Am. Jour. Sci., 4th ser., vol. 9, p. 435, 1900; Michigan Geol. Survey Ann. Rept. for 1901, pp. 244-251, 1902. 6 Lane, A. C, The Keweenaw series of Michigan: Michigan Geol. and Biol. Survey, Tub. 6, vol. 1, pp. 757-773, 1911. c Vertical depth not given. 1 Wheeler, H. A., Temperature observations at the Lake Superior copper mines: Am. Jour. Sci., 3d ser., vol. 32, pp. 125-129, 1886. Temperature observations in mines and holes in northern peninsula of Michigan.--Con. o Tho depths here given assume the surface to be 500 feet above Lake Superior, for in the original paper depths are given with the lako as the datum and the surface is irregular. Temperatures were all taken by S. Smillie, engineer. # The temperature of 57 at 1,080 feet in the Quincy mine appears anomalously high when compared with the record at greater depths The rate of increase calculated from the difference between the temperature at 1,080 feet and 3,875 feet is 1 in 147 feet; from 2,941 to 3,875 feet it is 1 in 81 feet on the basis of a temperature of 64.5 in the bore hole, and 1 in...