ROCK TEMPERATURES AT SYDNEY HARBOUR COLLIERY. 207 



RECORDS of ROOK TEMPERATURES at SYDNEY 



HARBOUR COLLIERY, BIRTHDAY SHAFT, 



BALMAIN, SYDNEY, N. S. WALES. 



By J. L. C. Rae, E. F. Pittman, Assoc, r.s.m., and Professor 

 T. W. E. David, b.a., f.g.s. 



[_ReadL before the Royal Society of N. S. Wales, December 6, 1899, ,] 



I. Introduction. — About seventeen years ago Professor J. D. 

 Everett, f.r.s., Secretary to the Underground Temperature 

 Committee of the British Association for the Advancement of 

 Science, furnished one of us (Professor David) with two slow-action 

 thermometers and one maximum thermometer for observing rock 

 temperatures underground. The thermometers were made by 

 Negretti and Zambra, and were tested at Kew Observatory. The 

 Kew certificates were forwarded with them and the corrections 

 applied in the table given later on in this paper are in accordance 

 with these certificates. 



The first opportunity for observing underground tempera- 

 tures near Sydney was afforded by the diamond drill bores for 

 coal, put down at Cremorne, Robertson's Point, Sydney Harbour. 

 The second of these bores was completed in November 1893. 

 The maximum thermometer, sent by Professor Everett, became 

 mislaid in the interval between the completion of the first and 

 second Cremorne bores, and when it became necessary to observe 

 underground temperatures at the No. 2 Bore, Mr. H. C. Russell, 

 B.A., c.m.g., f.r.s., Director of the Sydney Observatory, kindly 

 lent maximum thermometers for the purpose, similar to the one 

 sent by Professor Everett, but not protected by a thick, hermeti- 

 cally sealed outer glass casing. It was, accordingly, necessary to 

 protect these thermometers against the water pressure at the 

 bottom of the bore, and this was done efficiently, though the 

 method is cumbrous, by enclosing the thermometers in a strong 



