[. li J 
Explication of fome Technical Terms. 
AS-this volume may poffibly fall 
into the hands of fome who have 
not yet read the works of Dr. 
Prieftley, and are entirely ftrangers 
to the new doétrine of air; I think 
it will be ufeful to explain the 
meaning of the new invented names 
eR. to eed pees, of a1 air men- 
oe air is <a kind of per- 
manent elafiic fluid which is ex- 
tracted by nitrous acid or aqua 
fortis from the moft part of metals, 
‘principally from mercury, brafs, 
copper, &c. This air is by a 
bended glafs tube conducted under 
d 3 an 
