184. ESSAYS anp OBSERVATIONS 
which may poflibly be different from thofé 
of the fea, 
Macngsta is not lefs remarkably di- 
ftinguifhed from the calcarious earths, by 
joining it to the nitrous and vegetable a- 
cids, than to the vitriolic. Thofe earths, 
when combined with fpirit of nitre, can- 
not be reduced to a cryftalline form, and, 
if they are diffolved in diftilled vinegar, 
the mixture fpontaneoufly dries up in a 
friable fale. 
Havinc thus found magunefia to differ 
from the common alkaline earths, the ob- 
ject of my next inquiry was.its peculiar de- 
gree of attraction for acids, or what was 
the place due to it in Mr Geoffroy’s table 
of elective attractions. 
THREE drams of magnefia in fine pow- . 
der, an ounce of falt ammoniac, and fix 
ounces of water, were mixed together, and 
digefted fix days in a retort joined toa re- 
ceiver. 
Durinc the wholetime, the neck of the 
retort was pointed a little upwards, andthe — 
moft watery part of the vapour, which — 
was condenfed there, fell back into its bo- 
dy. 
