112 



E. F. PITTMAN. 



internal heat of the earth, have not shown very consistent 

 results in other parts of the world, as will be seen by the 

 accompanying table : — 



Observed Temperatures in Excavations. 





Depth in 



Depth in feet 



Locality. 



feet of 



for increase 





Excavation. 



of 1° F. 



Bootle Waterworks (Liverpool) 



1392 



130 



Przibram Mines (Bohemia) ... 



1900 



126 



St. Gothard Tunnel 



5578 



82 



Mont Cenis Tunnel ... 



5280 



79 



East Manchester Coal Field ... 



2790 



77 



Paris Artesian Wells... 



1312 



56-7 



London Artesian Wells (Kentish Town) 



1100 



55 



Yakoutsk frozen ground (Siberia) 



540 



52 



Sperenberg Bore (Berlin) 



3492 



51-5 



St. Petersburg Well (Russia) 



656 



44 



Carrickfergus, shaft of salt mine 



770 



43 



,, ,, ., 



570 



40 



Slitt Mine, Weardale, Northumberland 



660 



34 



Fort Randall Artesian Bore, Dakota, U.S.A. 



576 



17-5 



In view of the extremely wide differences in the tempera- 

 ture gradient, as shown by these figures, it would surely 

 be very illogical to contend that, because some Australian 

 artesian bores give higher rates of increase than the average 

 of those results quoted above, the water must be plutonic 

 and not meteoric. 



In the Dakota artesian basin the temperatures of the 

 waters from flowing wells show even more remarkable 

 anomalies than those in Australia. Darton 1 mentions that 

 at the Fort Randall well, in the Missouri Valley, the rate 

 of increase of temperature is 1° for each 17i feet, while at 

 the Chamberlin well the rate is 1° for each 21f feet, and 

 at the Pierre well 1° for each 24i feet. In other parts of 

 the basin the rate varies down to 1° for each 41 feet. 

 Darton also draws attention to the fact that the area 



1 Geothermal Data from deep artesian wells in the Dakotas, N. H. 

 Darton, Quart. Journ. Sci , Vol. v., 1898, pp. 161 - 168. 



