He firied with vapour a receiver previoufly exhaufted of air j 

 the receiver contained an hygrometer w^hich flood at XCVIII, and 

 confeq-jently marked faturation with moifture ; and the tempera- 

 ture, both under the receiver and in the room, was 41^; no 

 moifture was depofited on the glafs. The receiver, in this ftate, 

 was carried into another room, whofe temperature was 32^ ; here 

 moifture, and even drops of water, immediately appeared on the 

 glafs, and the hygrometer indicated greater drynefs, for it flood at 

 XCI. And fo I think it fhould, for the quantity and denfity of 

 what vapour remained in the air were really diminifhed, drops 

 having been formed from part of it ; but after twenty minutes, the 

 hygrometer again moved to moifture, and finally flood at XCVII 

 and one-half, and the cold under the receiver was increafed fix 

 degrees. This too, it appears to me, fhould naturally be expeded ; 

 for, by the increafe of cold, not only the vapours in contad with 

 the hair are more condenfed, but its affinity to moifture is alfo in- 

 creafed ; it therefore abforbs more of them, and confequently 

 moves to moifture. On moving the receiver, in this laft ftate, 

 into a room whofe temperature was 45**, §, the drops condenfed 

 on its interior began to evaporate, and while this evaporation 

 vlafted, the hygrometer indicated an increafe of moifture, but foon 

 afterwards it moved to drynefs, and in three hours the tempera- 

 ture, being then nearly 48**, it flood at XG, becaufe the heat 

 being 16^ higher, diminifhed the affinity of the hair to moifture, 



and 



