204 ESSAYS anp OBSERVATIONS — 
perceive in them after this procefs, was 
not fuppofed to proceed from any addi- 
tional matter received in the fire, but feem- 
ed to be an effential property of the pure 
earth, depending on an attra@ion for 
thofe feveral fubftances which it then be- 
came capable of corroding or diffolving, 
which attraction had been infenfible as 
long as the air adhered to the earth, but 
difcovered itfelf upon the feparation. 
THIs fappofition was founded uponan 
obfervation of the moft frequent confe- 
quences of combining bodies in chy- 
miftry. Commonly when we join two bo- 
dies together, their acrimony or attrac- 
‘tion for other fubftances becomes imme- 
diately either lefs perceivable or entirely 
infenfible; although it was fufficiently 
{trong and remarkable before their union, 
and may be rendered evident again by 
-disjoining them. A neutral falt, which is 
compofed of an acid and alkali, does not 
poffefs the acrimony of either of its con- 
flituent parts. It can eafily be feparated 
from water, has little or no effet upon 
metals, ig incapable of being joined to 
in- 
