220 A Tribute to the Memory of 
_ The Essay on Ferments and Fermentation 
is valuable, not for the theoretical specula- 
tions which it contains, for these have been 
superseded by subsequent discoveries ; but 
for a few facts of considerable importance. 
It was at that time believed that the infusion of 
malt, called wort, could not be made to fer- 
ment, without the addition of yeast or barm; 
but Mr, Henry discovered that wort may be 
(2.) Observations on the Influence of Fixed Air on Ve- 
getation, and on the probable Cause of the Difference 
in the Results of various Experiments made for that 
purpose. 
In Vou. III. Observations on the Bills of Mortality for the 
Towns of Manchester and Salford. 
(2.) Case of a Person becoming short sighted i in cA 
Age. 
(3.) Considerations relative to the Nature of Wool, Silk 
and Cotton, as Objects of the Art of Dyeing ; on the va- 
rious Preparations and Mordants requisite for these diffe- 
rent substances ; and on the Nature and Properties of 
Colouring Matter—Together with some Observations 
on the Theory of Dyeing in general, and particularly 
the Turkey-Red. 
New Series, Vor. II. Remarks on Mr. Nicholson’s , Ac- 
count of the Effects produced at Swinton by a stroke of 
Lightning. " 
And a paper, printed in this volume, entitled Memoirs of 
the late Charles White, Esq. F, R. S. chiefly with 2 
Reference to his Professional Life and Writings... 
