106 PRESSURE OF A MIXTURE OF GASES. 



= kp (1 + /.), (1) 



or, / = _l = -273. 



In Fahrenheit's scale, the reading for absolute zero is 

 459. 

 Combining (1) of this Art. with (3) of Art. 54, we have 



p = kpa (t t ) 



= kpa (t + 273) = kpaT, (2) 



where T is the absolute temperature. 



If v and p be the volume and density of a mass of gas, pv 



vv 

 is constant, and therefore, from (2), ^~ is constant ; from 



which it appears that the product of the pressure and 

 volume of a given mass of gas is proportional to the 

 absolute temperature. 



SCH. If the difference of temperature between the freez- 

 ing and boiling points be divided into a hundred degrees, 

 as in the Centigrade thermometer, the freezing point will 

 then be 273 and the boiling point 373 absolute tempera- 

 ture, and the zero of the scale will be that temperature at 

 which the pressure vanishes. Denoting the absolute tem- 

 perature by T, and the ordinary Centigrade temperature by 

 t, we have 



T = 273 + t. (3) 



56. The Pressure of a Mixture of Gases __ If two 



liquids, which do not act chemically on each other, are 

 mixed together in a vessel which remains at rest, they will 

 gradually separate, and finally attain equilibrium with the 

 lighter liquid above the heavier. But if two gases are 

 placed in communication with each other, even if the 

 heavier be below the lighter, they will rapidly intermingle 



