830 



SCIENCE 



[N. S. Vol. XXXIII. No. 856 



feet and 7,347 feet, with bottom temperatures 

 of 158° F. and 181° F., respectively. 



Boclc Temperatures in Brazil Mines 

 (St. John Eel Eey Mine, Minas Geraes) 



Rock Tem- 

 perature at 



324 feet 70.0° F. 



e24 feet 71.0 



924 feet 74.0 



2,073 feet 78.0 



2,824 feet 84.5" 



3,724 feet 88.0 



4,024 feet 95.0 



Vertical depths of more than 4,500 feet are 

 reported reached at Bendigo, Victoria, Aus- 

 tralia, with a rock temperature of 110° F. at 

 4,000 feet. At the Adalbert mine in Bohemia 

 the greatest depth is stated to be 3,600 feet, 

 with a rock temperature between 3,500 and 

 3,600 feet of 113° F. 



Moclc Temperatures in Kalgoorlie Mines 



Rock Tem- 

 perature at 



1,400 feet 84° F. 



1,700 feet 83 



2,000 feet 83 



2,300 feet 84 



Data bearing on artesian-well temperatures 

 in the Dakotas were tabulated and discussed 

 by Darton'" in 1898, which indicated very high 

 and variable temperatures and for which no 

 satisfactory explanation was offered. Eecords 

 from 42 localities were given in which the 

 depth of well varied from 432 feet to 2,500 

 feet, and the rate of temperature increase 

 ranged from 1° F. in 17.5 feet to 1° F. in 45 

 feet, with an average of 1° F. in 35.4 feet. 

 At the Pittsburgh meeting of the Geological 

 Society of America, December, 1910, Mr. Dar- 

 ton read a paper entitled " A List of Under- 

 ground Temperatures in the United States " 

 in which he said : " The rate of temperature 

 increase has been found to be very variable, 

 but in places there is a marked relation to 

 geologic features." '^ 



" Equals sea level. 



^Darton, N. H., "Geothermal Data from Deep 

 Artesian Wells in the Dakotas," Am. Jour. Sci., 

 1898, Vol. V. (N. S.), pp. 161-168. 



The records of the Committee on Under- 

 ground Temperatures, of the British Associa- 

 tion for the Advancement of Science, show a 

 range of 1° F. in less than 20 feet to 1° F. in 

 130 feet, with an average of 1° F. in 64 feet. 

 Professor Prestwich concluded that the av- 

 erage increase in temperature was 1° F. in 

 47.5 feet (p. 55). Lord Kelvin assumed the 

 rate of increase to be 1° F. in 51 feet. A 

 lower rate of increase is indicated in more 

 recent deep borings that have been carefully 

 measured. From the data giVen above, quoted 

 from the article by Weston on increase of 

 temperature with depth in metalliferous 

 mines, the general rate of increase in thermo- 

 metric gradient for the different localities is : 

 in the Witwatersrand mines from 1,000 feet 

 to 8,000 feet, 1° F. for each 250 feet in depth; 

 in the copper mines of the Lake Superior dis- 

 trict, 1° F. for each 209 feet; in the St. John 

 Eel Eey mine, Brazil, 1° F. for each 156 feet, 

 approximately; and in the Kalgoorlie mines, 

 Australia, practically no variation in tempera- 

 ture is indicated between the depths of 1,400 

 feet and 2,300 feet. 



Professors Chamberlin and Salisbury give 

 the following list of records :" 



Depth 

 Locality in feet RiseofloF. 



Sperenberg bore (Germany) .. 3,492 in 51.5 feet 



ScMadeback bore (Germany) . 5,630 67.1 



Cremorne bore (N. S. Wales) . 2,929 80 



Parusehowitz bore (Upper Si- 

 lesia) 6,408 62.2 



Wheeling well (W. Va.) 4,462 74.1 



St. Gothard tunnel (Italy- 

 Switzerland) 5,578 82 



Mt. Cenis tunnel (France-Italy) 5,280 79 



Tamarack mine (N. Mich.) . . 4,450 100 



Calumet and Heela mine (N. 



Mich.) 4,939 103 



Ditto, between 3,324 feet and 4,837 93.4 



In commenting on these records the authors 



13 < 1 Preliminary List of Papers, 23d Winter 

 Meeting, Geol. Soc. America, Pittsburgh, Pa., ' ' 

 December, 1910, p. 2. 



" ' ' Geology, ' ' Vol. I., Geologic Processes and 

 their Eesults, 1904, p. 543. 



