12 EXPERIMENTS ON 



sonings sufficiently known. An example, however, 

 may not be deemed superfluous. 



EXAMPLE. 



The lowest degree to which the barometer de- 

 scended during the course of these experiments, was 

 Q6. 85 inches =:^', when the temperature also least 

 of all was 69°. These two quantities are used as 

 constant in the computations. 



Now, on the 7th of August, at 6"' 39' A. M. the 

 barometer was oberved to be at Q7=B 

 from which deduct Q6 85=^' 



there remains, 15=B — B' 



Again, the thermometer at the same time 

 was 75 ° 



from which deduct 69 



and we have 6~n ; and as no difference 



of temperature was noticed in the atmosphere and 

 mercury, the same quantity (6) will also be ex- 

 pressed by d. 



Hence it is that having found, 

 B—B-0. 15; ^^«-»-=i-=:0. 99, &c.; and ±Ai_-zn=o. 

 98, &c. we have 0. 15 x 0. 99 x 0. 98 = o! H5530; 

 which to reduce in terms of B (the least density) we 

 have ^-^^ zz — ^— the increase of density. 



14 5 5 3 



Lastl}^, to obtain an expression in absolute num- 

 bers, we have, as 26. 85 : 26. 85+y|^::]000 : 1000. 

 202, the quantity entered in the tables. 



The remaining columns are sufficiently explicit to 

 .require no explanation. v^ 



