and on the Expamion of Moist Air. 433 



any kind of air as when j)ure : Indeed by his 

 own method, it is evidently so at that point 

 where the pressure was equal to 'J« or 30 

 inches ; that is, about the temperature 60 

 or (55'. 



Mr. Gough will hence be enabled to learn 

 how far he and I have been misled by my 

 theon' when we both calculated that Schmidt 

 made his experiments on air of 1.5 or 16 inches 

 of pressure. '^-^ 



, Upon looking over the numbers Mr. Schmidt 

 has given for the expansion of moist air, it is 

 evident he has gone upon the supposition that 

 the space occupied by any volume of moist air 

 (or rather air confined by water) is inversely as 

 the pressure. Thus, the space occupied by 1 

 measure of dry air at a given pressure and tem- 

 j>erature oi 32'^, being 1.3574, at 212% he infers 

 ihat by admitting water to it the space would 

 become 2.3574 ; that is, according to him, if 

 1,000 part of air at 32** and 28 inches pressure 

 be heated to 212% it will require a pressure of 

 38.0072 Inches to retain it in the same space 

 by reason of its increased elasticity ; and if to 

 ■ this, water be admitted, it will then require 

 the addition of 28 inches more, or 66.0072, 

 to retain it in tlie same space (see page 351). 

 Now this last is strictiy true in fact-, but the 

 former by no means follows as a consequence^ 



