DEPENDING ON THE HEIGHT ABOVE THE EARTH'S SURFACE. 455 



lected in comparison of the others. Then finding the numerical vahies 

 of A and B by comparing the two expressions for 6, we shall obtain, 



clz ~ 964 "^ 6624505 "^^"J"- 



This result accords with the preceding theoretical considerations in 



giving a positive value to -^. It also enables us to estimate to what 



amount the variation of the atmospheric temperature with the height 



above the Earth's surface is affected by causes distinct from that of 



variation of density. It appears, that for small altitudes the term in 



do 

 equation (5) involving -r- is about one-fourth the other term. The 



formula of Atkinson from which these inferences are made, is strictly 

 applicable only to the lower parts of the atmosphere where the grand 

 aerial currents prevail, beyond which the law of the decrement of 

 temperature probably undergoes some variation. 



I have thus endeavoured to advance in the theoretical part of this 

 problem, as far as the present state of our knowledge appears to admit, 

 and to give as much exactness as possible to the mathematical reasoning. 

 With respect to the latter, the course pursued in this paper may lay 

 some claims to originality, but the fundamental principles regarding the 

 atmosphere are not essentially different from those advanced by Dalton 

 and Ivory in their writings on this subject. 



