Mean Temperature of the Earth at Sydney. %%7 



a degree from 6S # , the temperature deduced from Dr Brew- 

 sters formula. 



By another set of observations, Sir Thomas had found that 

 the mean temperature of the earth at Paramatta was only 

 61 °9, though almost in the same latitude ; and though the 

 depth of the thermometer in the bores was at an average not 

 above 14 feet. The observations at Sydney are on the 

 other hand made at depths of eighty-four feet, and hence 

 there is reason to believe, that this excess of the temperature of 

 the earth at Sydney over that at Paramatta, viz. 2° nearly, is 

 owing to the depth at which the observation was made, and 

 consequently to the same cause which occasions a rise of tem- 

 perature as we descend into deep mines. 



We are aware, that there is a great difference between the 

 mean temperature of the atmosphere at Paramatta, and at 

 Sydney, but this cannot explain the increase of heat at Syd- 

 ney, at a depth of 84 feet. 



Register of the Temperature of the Well at the Prisoners* 

 Barrack, Sydney, from March 12, 1 824, to March 14, 1825. 



