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



Inverse Formula for calculating the Temperature from the 

 Maximum Elasticity of Steam : 



^=y= 



Loff P. _^_/3" 



y iy^ 2y 



Values of the Constants depending on the Thermometric 

 Scale. 



For the centigrade scale : — 



Absolute zero 274°-6 below the freezing point of water. 



Log /3=3-1851091 Log y=5-082717B 



-A=0-0063294 — =0'0000400G 



For Fahrenheit's scale ; boiling point adjusted at 29-922 

 inches. 



Absolute zero 462°-28 below ordinary zero. 



Log /3 = 3-4403816 Log y=5-5932623 



— = 0-0035163 —-=0-000012364 



2 y i y" 



For Fahrenheit's scale ; boiling point adjusted at 30 inches. 

 Absolute zero 46]°*93 below ordinary zero. 



Log /3 = 3-4400625 Log 5/= 5-5926244 



-^ = 00035189 _^=0-000012383 



2 y 4 J.2 



Values of the Constant a, depending on the Measure of 



Elasticity. 



For millimetres of mercury .... a = 7'831247 



English inches of mercury .... 6'426421 

 Atmospheres of 760 mil. =29-922 1 



inches = 14-7 lbs. on the square inch > . 4-950433 

 = 1-0333 kil. on the centimetre^ J 

 Atmosphei'es of 30 inches = 761 mil. -99 ] 



= 14-74 lbs. on the square inch I . 4-949300 

 = 1-036 kil. on the centimetre^ J 



Kilogrammes on the square centimetre . 4*964658 



Pounds Avoirdupois on the square inch . 6*117817 

 N.B, — All the Constants are for common logarithms. 



I have applied similar formulae to the vapours of alcohol 

 and ether, making use of the experiments of Dr ITiv. 



