CATALOGUE.'— HEAT, EXPANSION. 



391 



It may be inferred from'Deluc's experiments, that the mercurial thermometer may be reduced to anatural scale by adding to 



jnti 

 the temperature that it indicates .07 ' m beiivg the number of degrees above the freezing point, and n the number 



below the boiling point, m + n of course 180, 80 or 100, according to the scale employed. These experiments ought, 

 however, to be repeated by mixing various fluids, before we can be confident that their results are perfectly natural. 

 Besides Dr. Crawford, another most able philosopher has found the mercurial scale less at variance with the natural one. 

 According to this correction, 650" would be reduced to 540° for the boiling point of mercury on the natural scale j 

 Hut Wedgwood's silver gage makes it about 607". 



TABLE OF THE NATUBAt SCALE, ACCORDING TO DELUC. MODIF. DE l'aTM. 30p. 



Merc. R. Nat. R. Form. R. Merc. R. Nat. R. Form. R. 



Richraann also found the expansion greater than in proportion to the heat ; and if the apparent difference in his expe- 

 riments had arisen from this circumstance only, it would have indicated an inequality more than twice as great as is' 

 shown in those of Deluc. 



