C 46r ] 



if the barometer below be at 30 inches we have log. 30 = 477 1 2 1 

 — 4666,66 = log. 010455, which denotes the natural number 

 10,244; and if the lower barometer be at 29,8 we have log. 

 474216 — 4666,66 = log. ,007550, which denotes the natural 

 number 10,176. 



And thus we find that' the Variations of the"; barometer at 

 great beights are generally fmaller than thofeof(the inferior 

 barometer,* as De Luc and SaufTufe have alfo remarked. 



Thus the variation of the inferior barometer in this cafe is 

 0,2 of an inch, and the correfpondent variation of the higher 

 is only ,0068 of an inch?'' <?^- ^'^ :?■ 



■ -^Ye'i'' ^5fftietiwies' frorm bcfal caufes which difturb the natural 

 ^rdgreflion of heat, the variations of the. barometrical height 

 above are greater or fmaller, than, proportionally to the baro- 

 metrical height below, they ought to be ; but the difference is 

 inconfideratle, though 'imlportant, when the meafurement of 

 teigh'tsis aimed at. '^^ abinu ,b3n;mi333'b grf .ion. 



.j.'on;! ollr "' .Pj^oblem II. . . 



"-■'•S • flf i-flf., ... 



THEneiglit of merctiry iii a barometer at any. elevation in 



the atmofphere being given or found, and alfo the height of 



mercury in a barometer vertically below that height, to find the 



Vol. VIII. 3 M -weight 



* ySauflure, 8vo. § 2049, p. 388. 



