[ 272 ] 



experiments, he has been enabled to make it indicate very nearly 

 the ahfolute quantities of moiflure contained in given cubic 

 meafures of atmofpheric air of given denfities and temperatures. 

 Of this inftrument and its ufes, as Mr. Sauffure's treatife has 

 never been tranflated into our language, and feems unknown to 

 our meteorologifts, I fhall give an abridged account in the fol- 

 lowing pages. 



Mr. De Lie has alfo bellowed much laudable induflry in per- 

 fedting an inflrument, applicable to the fame purpofes, but lefs 

 fragile ; how far he has fucceeded I am not enabled to fay, not 

 being pofleffed of it. 



Baromtiers have been brought to the utmoft degree of perfec- 

 tion by the fagacity and unremitting labours of Mr, Dc Luc, as 

 may be feen in his immortal work on the modifications of the 

 atmofphere. The varying denfities of the atmofphere at dif- 

 ferent heights (denied by Buffon) have been fatisfadorily proved 

 by the numerous and happily contrived experiments of Meffrs. 

 Sauffure the father and fon. See 36 Roz. p. 98. 



Thermometers have long fince been improved by Fahrenheit 

 and Reaumur; but the imperfedions and uncertainties attending 

 many under this laft denomination have been deteded by Mr. De 

 Luc, who in their room introduced a much more perfedt inftru- 

 ment 



I 



