[ 457 ] 



Having given, p. 436, &c. the foliuion of feveral problems 

 when the mean temperature of the atmofphere is at 32^, I fhall 

 now fhewT how fimilar refults may be obtained when the mean;- 

 temperature is above 32^. 



Problem ift, 

 * 



To find the height mercury would ftand at in a barometer on a 

 given elevation in a known latitude in fummer and in clear 

 weather, when the height at which it ftands at the bottom of that 

 elevation and the temperature of the atmofphere below are alfo 

 given. 



Solution i °. 



From the latitude deduce the height of the line of congelation, 

 (fee the table, p. 361,) and from the height of this line, and the 

 temperature of the air below, deduce the temperature at the given 

 height, as fhewn p. 362. The temperature above mufl alfo be 

 deemed that of the mercury in the upper barometer, as, if it were 

 expofed to the air a fufficient time, it would certainly affume it. 



a*'. Convert the meafure of the elevation into fathoms, 

 and fubftrad thefe fathoms from the logarithm of the height 



of 



