460 MM. Jamin and Richard on the Laws of Cooling, 



It is now proved that the coefficicDt of log h is independent of 

 the pressure ; but as the various right lines differ by their ordi- 

 nate at the origin, log A must be a function of H, a function we 

 will now seek. 



If, for that purpose, we give to log h any constant value what- 

 ever, for example 2'000, and take from the various right lines the 

 corresponding value of log(r'— r) for the pressure H to which 

 each line corresponds, we get 



log A= log (r'-r) - 1-02 x 2-000. 



We next construct these values of log A, taking H for abscissa, 

 and obtain as many points as there were values of H. Now 

 these points arrange themselves again in a very well-drawn right 

 line which makes with the axis of the abscissae an angle whose 

 tangent is 0'88. Its equation is 



logA=log^-0-88logH. 



The following numbers show the agreement of the observations 

 and the calculation : — 



H. 



814-5 

 788-4 

 656-2 

 587-7 

 543-2 

 481-3 

 407-3 

 313-2 

 182-3 

 73-9 



Supposing now that H 



n 



\ 



Observed. 



Calculated 



819 



819 



847 



847 



954 



971 



1024 



1084 



1203 



1163 



1320 



-1311 



1526 



1498 



1843 



1868 



2988 



2954 



6494 



6637 



and h are both variable, on substitu- 



ting for A in equation (2) its value we have 



log (r'-r) = log ^-0-88 log H + 1-02 log A, 



or 



(3) 



r = k 



JJ088 - 



/; is a constant determined by the whole of the measurements. 



On making the same observations for air and carbonic acid, 

 we arrived at the same formula, 



^* 



The following are the values of a and /S : — 



Carbonic acid. Air. Hydrogen. 



a . . 0-79 0-88 1*02 



P . . -0-61 -0-80 -0-88 



