[ 338 ] 



Note. — 1°. Moft of the interpolations from the 88th degree 

 to the 1 22nd I have myfelf inferted as thofe calculated by 

 Schmidt erred too widely by his own account. 4 Gren Phyf. 

 Jour. 273. ^ 



ado. Mr.Pictet has alfo made a fet of curious experiments on 

 the elafticity of pure vapour in low temperatures. Effais de 

 Phyftque '^. 157. He found that a grain of warm water in vacuo 

 evaporates in forty minutes in the temperature of 38' Fahr. under 

 a receiver containing 1452 Englifh cubic inches,* but that it did 

 not diffufeitfelf equally in lefs than fix hours, and then raifed the 

 hygrometer from 17* to 60^ ihat is 43**, and during this whole 

 •time the cold under the receiver was conftantiy dccreafing, though 

 .flowly, which decreafe undoubtedly contributed to the diffufion 

 of the vapour. 



Mr. Schmidt has alfo made a feries of experiments upon the 

 •dilatibility of air, made as dry as poflible by expofure to hot tar- 

 tarin, an objed of great importance, that had never before been 

 examined. This table I here infert, converting Reaumur's de- 

 grees Into thofe of Fahr. and adding from his form,ula the degrees 

 he omitted. 



'Expanfton 



*Ibid. page pi. 



