382 Elements of Mineralogy. 



which is to be added to 20,4 29> ^ C \> ^ 



+ ,0145 ^ 



29,415 its cor reded height 



Again the upper barometer is at 25,19 in- 

 ches, and its attached thermometer at 46 then 

 72 9. and ,02736 and h ^25,19 x 02736 



30" "^cT 



= ,02297 x and 25,i9 + o2297r:25,2i297 

 or in round numbers 25,213 as its corrected 

 height. 



Now the logarithm of 29,415 is 1,468568, 

 and the log. of 25,21$ is 1,401624, whofe 



4685,68 

 difference is - 4016,2;). 



669,44 



The difference of the 4 firft figures on the 

 left, gives the number of fathoms, and is 

 therefore feparated by a comma from the laft, 

 which gives the decimal parts of a fathom, and 

 669,44, x 6 4016,664 feet, this is the ap- 

 proximate height. 



The mean temperature is next to be found. 

 The detached thermometer A was at 39,51 an d 

 the detached thermometer B at 45, now then 



39>5 



