V The P R E F A C E. 
• Where it appears by many chymio flat teal 
Experiment Sy that there is dijfnfed thro* all 
naturaly mutually attraWmg bodieSy a large 
proportion of particle s^ which y as the fir fl great 
Author of this important difeovery. Sir Ifaac 
N c w ton 0 [fervesy are capable of being thrown 
off from denfe bodies by heat or fermentation 
into a vigor oufly elaflick and permanently re- 
pelling flate: And alfo of returning by fer- 
mentation and fometimes without ity into 
denfe bodies $ It is by this amphibious pro- 
perty of the airy that the main and principal 
operations of Nature are carried on ; for a 
mafs of mutually attracting particleSy with- 
out being blended with a due proportion of 
elaflick repelling one Sywould in many cafes foon 
coalefce into a fluggifh lump. It is by thefe pro- 
perties of the particles of matter that he folves 
the principal Thoenomena of Nature. AndT>r. 
Freind has from the fame principles given a 
very ingenious Rationale of the chief opera- 
tions hi Chymiflry. It is therefore of impor- 
tance to have thefe very operative properties of 
natural bodies further afeertained by more 
Experiments and Obfervations : And it is 
with fatisfaClion that we fee them more and 
more confirmed to usy by every farther enquiry 
we 
