( 189 ) 



in general more perfect than in the case of the last volume. The 

 rule that /\p is proportional to a* (1— '^O involves that for .;• ^ V, a 

 value must be found that is V3 times larger than that for .r = '/^ or 

 Vj. From Mr. Kuen^n's value a greater proportion is generally found 

 for it. At r=:403°,3 the proportion found in the case of the four 



, , 0,89 1,52 3,2 ^ 9,9 



before-mentioned volumes is , , and ; so values 



0,555 0,954 2,05 7,1 ' 



varying between 1,6 and 1,4. 



. rr. o , , . , 11'9 3,7 1,78 , 1,04 



At T= 878 , the values tound were , , and : 



' 8,875 2,55 1,19 0,68' 



so they are varying between 1,5 and 1,35. 



But at T= 343°, we may consider the proportions found as 

 equal to V3. 



According to the remarks, deduced from equation (6), the depen- 

 dence of hp on the volume must be expected less great than pro- 

 portional to the squares of the density. This may be considered as 

 being confirmed by the values, given by Mr. Kuenen. So Mr. Kuenen 

 finds, if v= 0,Q A;, = 0,81 and if i- = 0,03 A„ = 2,9 and if 

 v=z 0,045 hp= 1,38 etc. 



The dependence on the temperature, for w'hich according to equa- 

 tion (5) 



{-Ap)j,-{-Ap)^=2—^--^ ^^f(l-.r) 



would hold, and according to which formula for the same value 

 of X and V the differences of the observed values of A;, would be 

 proportional to the differences of temperature, is not confirmed by 

 Kuenen 's figures. But in all this we must not overlook the fact 

 that the Lp's are already difTerences of observed quantities and not 

 the observed quantities themselves, while \{—Ap)T2 — { — A;))r,! are 

 again differences from these differences. It is therefore to be regretted, 

 that there are so few observations, which may be used for this 

 investigation, and specially that Mr. Amagat has not been able 

 to continue his investigation of the mixture C0„ and N^ '). 



If we try to calculate a value for o,„ from the observed value of 

 hp, e.g. from the observation with v r= 0,06,, .« ^ %, 1*= 373 

 which gives Ap = — 0,7, this can of course, only be done by 



') C. E.. Acad, des Sciences. 11 Juillet 1898. 



