a 
PHYSICAL anv LITERARY. 241 
the relative ftrength of their feveral at- 
_ trations. 
_.. © Twenty four grains of magnefia in 
fine powder were mixed with five ounces 
of the cauftic ley ina {mall phial, which 
was immediately corked and fhaken fre- 
quently for four hours. The ley was then 
poured off,and the magnefia wathed with 
repeated affufions of water, and dried. It 
- had loft about the half of-its weight, and, 
when reduced to a fine powder, was readi- 
ly diflolved by acids with an effervefcence 
which was hardly perceivable: The al- .- 
kali had therefore extracted its air. I al- 
fo threw fome frefh magzefia into the ley 
- which had been poured off, and thereby 
rendered it perfectly mild and fimilar to a 
folution of falt of tartar; fo that it effer- 
_ vefced brifkly with acids. 
WitTH an ounce of the mild fpirit of 
falt ammoniac, I mixed a dram of magne- 
_ fra in very fine powder which had been 
__ previoufly deprived of its air by fire; and, 
a. obferving that the magnefia had atenden- 
_ cy to concrete into a folid mafs, I fhock 
SeViou. Il. Hh the 
