Of BAROMETRICAL MEASUREMENTS. 105 



ft, i 



_ 



pfmB v pfmuvQ 8 . ,,..,. 



py+ ja K J + FJ WK - - = yx, and, dividing by j, 



*" 





 yy 



To exterminate from this equation y and y t it is to be re 



marked, that v = - ^ ~r , and that therefore 



' 



M /l ^tufa Q 



. Hence, by fubffttution, x 



v ft " 



^ i ^u i _ a a 3 jtt j 



* JL + {^._A (i+f*)>|3 P f* 



2 2 2 p 



But 



. 

 therefore x = p( | -- JjW_ -- 1 ^ ^g other terms deftroying 



* 



one another. By integration, then,'* p( hg.$ ^-^--+C). 



If C be taken fuch that x may vanifh when (3 b y the height. 

 of the mercury in the lower barometer, we will have 



/ *\\ 



b fm(b 3 ) 

 . + J ^ ^ 



W 

 O 22. THAT 



