the late Mr, Henry. 221 
brought into astate of fermentation, by being 
impregnated with carbonic acid gas. By a 
fermentation thus excited, he obtained. not 
only good beer, but. yeast fit for the making 
of bread; and, from separate portions of the 
fermented liquor, he procured also ardent 
spirit and vinegar, thus proving that the fer- 
mentative process had been fully completed. 
He found, moreover, that. flour and water, 
boiled to the consistence of a thin jelly, and 
impregnated with carbonic acid in a Nooth’s 
machine, passed into fermentation, and by 
the third day had assumed the appearance of 
yeast, for which it served as a tolerable sub- 
stitute in the baking of bread. 
The other memoir, which is distinguished 
by its valueand importance, is entitled “ Con- 
siderations relative to the Nature of Wool, 
Silk, and) Cotton as Objects of the Art of 
Dyeing; on the various Preparations and 
Mordants requisite for these different Sub- 
stances ; and on the Nature and Fah of 
Colouring Matter.’’ f 
After having given a general view of the 
history of the art of Dyeing, Mr. Henry, in 
this elaborate Essay, examines the theories, 
that had been framed to account for the vari- 
ous facilityand permanency, with which diffe- 
rent substances attract colouring matter. He 
