RELATION OF VAPOUR AND AIR 565 



Yet this theory did not fall without an obstinate 

 struggle. It was taken up by the new school of 

 French chemists, and connected with their views 

 of heat. Indeed it long appears as the prevalent 

 opinion. Girtanner 7 , in his Grounds of the Anti- 

 phlogistic Theory, may be considered as one of the 

 principal expounders of this view of the matter. 

 Hube, of Warsaw, was, however, the strongest of the 

 defenders of the theory of solution, and published 

 upon it repeatedly about 1 790. Yet he appears to 

 have been somewhat embarrassed with the increase 

 of the air's elasticity by vapour. Parrot, in 1801, pro- 

 posed another theory, maintaining that De Luc had 

 by no means successfully attacked that of solution, 

 but only De Saussure's superfluous additions to it. 



It is difficult to see what prevented the general 

 reception of the doctrine of independent vapour; 

 since it explained all the facts very simply, and the 

 agency of air was shown over and over again to be 

 unnecessary. Yet, even now, the solution of water 

 in air is hardly exploded. M. Gay-Lussac 8 , in 1800, 

 talks of the quantity of water "held in solution" by 

 the air; which, he says, varies according to its 

 temperature and density by a law which has not 

 yet been discovered. And Professor Robison, in the 

 article "Steam," in the Encyclopaedia Britannica 

 (published about 1 800), says 9 , " Many philosophers 

 imagine that spontaneous evaporation, at low tem- 



7 Fischer, vol. \ii. 473. * Ann. Chim. torn, xliii. 



9 Robison's Work, ii. 37- 



