400 ESS‘ YS anv ee 
IN another experiment of the fame 
kind, I ufed the vitriolic acid with the 
fame event, 
ANY calcarious matter reduand. to a 
fine powder, and. thrown into a warm fo- 
lution of alum, immediately raifes.a brifk. 
effervefcence. But the powder is not dif 
folved ; it is rather increafed in, bulk: 
And if the addition, be repeated until it is 
no longer accompanied with eflerveicence 
the liquor_lofes all taftéof the alum, and 
yeilds only a very light cloud upon the ad- 
mixture of an alkali, 
From this experiment we learn, that 
acids attract the calcarious earths more 
ftrongly than they do the earth of alum ; ; 
and as the acid in this falt is exa@ly the 
fame with the vitriolic, it compofes with 
the calcarious earth a neutral fubftance; 
which is very difficultly foluble in water, 
and therefore falls down to the bottom of 
the veilel along with the, earth of alum 
which is deprived of its acid. The light 
cloud formed by the alkali proceeds from: 
the minute portion of the calcarious com- 
pound which faturates the water. 
3 THE 
