PHYSICAL AND LITERARY. 175^ 



pleat the folution, and no weight was loftin* 

 the experiment. 



As in the reparation of the volatile from 

 the fixed parts of bodies, by means of heat, 

 a fmall quantity of the latter is generally rai-, 

 fed with the former; fo the air and water, Or^. 

 riginally contained in the mag?7e/lay and after- 

 wards diffipated by the fire, feem to have 

 carried off a fmall part of the fixed earth of 

 tjiis fubftance. This is probably .the rea- 

 fon, why calcined magnejia is faturated with 

 a quantity of acid, fomewhat lefs than what 

 is required to diffolve it before calcination ; 

 and the fame may be afijgned as one caufe 

 which hinders us from reftoring the whole of 

 its original weight, by folution and precipjta- 

 tioHk ■ 



I took care to dilute the vitriolic acid, in 

 order to avoid the heat and ebullition which 

 it would otherwife have excited in the water ; 

 and I chofe a Fiorejitirie flafk, on account of 

 its lightnefs, capacity, and iliape, which is 

 pecuharly adapted to the experiment ; for 

 the vapours raifed by the ebullition circulated 

 for a (hort time, thro' the wide cavity of the 

 vial, but were foon collected upon its fides, 

 like dew, and none of them feemed to reach 



the 



