for adjujling thermometers. 853 
time of pouring on water before the boiling point is 
marked, in order that the water may recover its full 
ftrength of boiling, which is in good meafure checked 
by pouring on the boiling water. 
In this method the boiling point fhould be adjufted 
when the barometer is at 29.8 inches, that is, the fame 
as when the firft method is ufed ; the water fhould boil 
faft, and the thermometer fhould be held upright, with 
its ball two or three inches under water, and in that part 
of the vefTel where the current of water afcends^. 
Whichever of thefe methods of adjufting the boiling 
point is ufed, it is not neceffary to wait till the barometer 
is at the proper height, provided the operator will take 
care to corredt the obferved height according to the fol- 
lowing table. 
(m) In a veffel of boiling water one may almoft always perceive the current 
of water to afcend on one fide of the veffel 5 and to defcend on the other* . 
Height 
