PHYSICAL AND LITERARY. 83 



contradided by many noted experiments. 

 Mr Gauteron of the French Academy 

 has made it appear, that fluids lofe more 

 by evaporation in fevere froft than in 

 moifl and warm air : Therefore evapo- 

 ration cannot depend, folely at leafl, up!-' 

 on gravity, even though affilled by' 

 heat. 



From various experiments, we have 

 reafon to believe, that evaporation de- 

 pends in fome meafure upon heat. This' 

 facl probably has fuggefted the forego- 

 ing theory, accounting for evaporation- 

 by the rarefa6lion of air ; and it is ftill' 

 more probable, that it has alfo fuggefted- 

 die following theory, accounting for it- 

 by the rarefadion of water. DocIHior De- 

 fagulier, whofe theory it is, reaforis thus 

 Water is expanded by heat; and fup- 

 . poling it to be expanded to a bulk more 

 than 800 times greater than in its ufual 

 ftate, it becomes fpecifically lighter than 

 ordinary air, and muft confequently rife 

 in it till it meet with air above of its own 

 degree of rarefadlion. To illuftrate this 

 theory, he obferves, that boiling water, 



when 



