[342 ] 



Note. — Iq. Hence we fee that air faturated with moiflure at 

 high heats is much more expanded than dry air of the fame tem- 

 perature, as De Luc and General Roy have alfo obferved, but in 

 temperatures below 36*', 5 dry air is more dilatable which probably 

 induced Sauffure to conclude it was fo at higher temperatures. 

 At 54,5 the difference is very perceptible for 1000 parts dry air at 

 Sa'' are expanded at 54.°,5 that is by 22^,5 above the freezing point 

 to 1044,67, whereas 1000 parts of air faturated with moifture, 

 are extended to 1064,72 and in higher heats, the differences of 

 cxpanfion are incomparably greater. 



ado Hence it is plain why moift air, fuch as that of the Weft 

 Indies is much more fuffocating than dry air of the fame tempe- 

 rature. For loco cubic inches of air faturated with moifture 

 at 86° of Fahr. contain nearly 76 inches of moifture which is 

 ufelefs to refpiration,, 



310. Thefe experiments agree with thofe of General Roy in 

 which fteam was introduced at hazard, for the General found that 

 from 32" to ^2° each- degree gave at a mean 2,588 and confe- 

 quently thefe 20*^ would expand 1000 inches to 1051,76, and by 

 Schmidt's experiments much more accurately made, we have 

 1050,33. 



40. Schmidt 



