40 W. J. M. Rankine, Esq., on the Elasticity of Vapours. 



The diagram shews that the formula agrees with the ex- 

 periments as well as their irregularity entitles us to expect. 

 The following Tables give some of the numerical results. 



Table VI. — Valour of Turpentine. 



Tempera- 

 tures in De- 

 grees of 

 Fahrenheit, 

 from the or- 

 dinarv zero. 



*304 

 310 

 320 

 330 

 340 

 350 



*360 

 362 



Pressures in Inches of Jlercurj 

 according to 



The Formula 

 (of two terms). 



30-00 

 32-52 

 37-09 

 4216 

 47-78 

 53-98 

 60-80 

 62-24 



Dr Ure's 

 Experiments. 



30-00 

 33-50 

 37-06 

 42-10 

 47-30 

 53-80 

 60-80 

 62-40 



Difterences 



1 between 



1 Calculation and 



Kxperiment in 



Inches of Mercur; 



0-00 



- 0-98 

 + 0-03 

 + 0-06 

 + 0-48 

 + 0-18 



0-00 



- 0-16 



Table VII. — Vapour of Petroleum. 



I have also endeavoured, by means of the first two terms 

 of the formula, to approximate to the elasticity of the vapour 

 of mercury, as given by the experiments of M. Regnault. 

 The data and the constants are as follows : — 



