296 Prof. Bischof on the Temperature of 



sition. The position of this shaft is such, that the circum- 

 stances must be supposed rather to resemble those at Geneva 

 and Rudersdorf, than those in the Erzgebirge ; but they in so 

 far resemble those of the Erzgebirge, that the influence of the 

 atmosphere, as Phillips remarks, can only cause a depression, 

 but not an elevation of temperature. 



However improbable, therefore, it may be, that perceptibly 

 different values should be found for n beneath plains and in 

 mountains, it would yet be desirable that such favourable cir- 

 cumstances as tliose at Geneva, in the Erzgebirge, and in the 

 English mines, should be more frequently met with and taken 

 advantage of. Then it would not be long before a general law 

 for the increase of temperature towards the centre of the earth 

 would be found. And if this law should suffer interruptions, 

 as all other physical laws do, yet a numerical expression for 

 such interruptions might possibly be discovered. 



The following Table is illustrative of the observations in 

 Chapter VI. of this article, at p. 362 of the 20th volume of 

 this Journal. 



Table — Temperatures of Springs. 



