ROCK TEMPERATURES AT SYDNEY HARBOUR COLLIERY. 



223 



Note. — From 1,150 feet downwards, the thermometers were 

 placed in the holes in pairs, one slow-action and one maximum 

 thermometer being inserted in each hole, as follows : — 







No. 1 Hole. 



No. 2 Hole. 



the 1150 feet level 



Thermometers — 

 Nos. 50452 and 65294 .. 



Thermometers — 

 . Nos. 50454 and 15888 



„ 1200 

 „ 1250 



» 



„ 50452 „ 65294 .. 

 „ 50452 „ 66294 .. 



„ 50454 „ 15888 

 „ 50454 „ 15888 



„ 1300 



„ 



„ 50452 „ 15888 ... 



„ 50454 „ 65294 



„ 1350 



„ 



„ 50452 „ 65294 .. 



„ 50454 „ 15888 



„ 1400 



>j 



„ 50452 „ 15888 .. 



„ 50454 „ 65294 



„ 1449 



„ 



„ 50452 „ 65294 .. 



„ 50454 „ 15888 



In the observations of rock temperatures at the No. 2 Cremorne 

 Bore (referred to in the introduction to this paper) the mean 

 annual surface temperature at Sydney was taken as 63° Fahr. 

 (this having been determined by Mr. H. C. Russell, f.r.s., Director 

 of the Sydney Observatory), whilst the stratum of invariable 

 temperature was assumed to be 15 feet below the surface. On 

 this basis the average rate of increase of temperature downwards, 

 in the Birthday Shaft will be found to be 1° Fahr. for every 

 90-7 feet. 



V. Rock temperatures, observed elsewhere, for comparison with 

 the observations made in the Birthday Shaft, Sydney Harbour 

 Colliery : — 



Place where observations were made. 



Schladebach Bore, Prussia... 



Astley Colliery, Dukinfield 



Ashton Moss Colliery, Manchester 



Dukenfield Colliery 



St. Uothard Tunnel 



Lansell's Gold Mine, Victoria 



Prizbam Silver Mines, Bohemia ... 



Calumet and Hecla Lode, Lake Superior, U.S. A 





Depth in 

 feet. 



Feet for 

 1° Fahr. 





5,735 



65 





2,700 



72 





2,790 



77 





2,055 



83 





5,578 



82 





3,250 



111 





1,930 



126 



r, U.S.A. 



4,712 



223 



VI. Conclusion. — It is proposed to continue these observations 

 to the full depth to be reached by the Sydney Harbour Colliery 

 Shafts (nearly 3,000 feet), and it would, therefore be premature 

 as yet, to comment on the temperature curve obtained from the 

 observations made so far. 



