244 On the Fermentation and 
either in improving the process or ascertaining its 
products, until Dr. Priestley and the Duke of 
Chaulnes made their interesting experiments on the 
carbonic acid gas disengaged during the operation 
of fermentation. Soon after these important dis- 
coveries were communicated to the public, the ac- 
curate philosopher, whom _I first quoted, instituted 
a set of most valuable experiments on this subject ; 
and from their results established a firm base for 
farther enquiry. Before this period, all was unde- 
fined, and the chemist had nothing to direct his at- 
tention but scattered facts, many of which rather 
tended to confound than properly to conduct his 
investigation. 
The distillation of ardent spirits has met a similar 
fate to that of fermentation. The Egyptians, at a 
very early period, discovered the art of drawing spirit 
from wine. Modern chemists have left it in the 
rude hands of the ill-informed, and accident hasbeen 
the chief:contributor to its improvement. It is true 
that some of the proof spirits of commerce are pure 
and good, but this arises more from the nature of 
the wines from which they are drawn than from the 
superior skill of the distiller. ‘The sugar-cane ‘and 
the grape are easily attenuated by fermentation, and 
contain less fetid oil than malt; neither are they 
so liable to contract an‘empyreuma in the still. I 
was induced to begin this enquiry from a firm per- 
suasion, that it was possible, by means of known 
