[ *3 ] 
Vegetable acids are, in every refpedt, beft adapted 
to fining : the mineral acids are too corrofive, and 
even infalubrious in common beverage* 
It is remarkable that, during the converfion of 
ifinglafs into fining, the acidity of the menftruum 
feems greatly diminifhed, at leaft to tafie, not on ac- 
count of any alkaline property in the ifinglafs, pro- 
bably, but by its inveloping the acid particles. It is 
likewife reducible into jelly with alkaline liquors, 
which indeed are folvents of all animal matters j 
even cold lime-water difiolves it into a pulpous 
magma. Notwithftanding this is inadmiffible as. 
fining, on account of the menfiruum, it produces 
an admirable efifeft in other refpedts : for, on com- 
mixture with compoiitions of plafter, lime, &c. for 
ornamenting walls expofed to viciffitudes of weather,, 
it adds firmnefs and permanency to the cement ; and 
if common brick-mortar be worked up with this 
jelly, it foon becomes almoft as hard as the brick 
itfelf : but, for this purpofe, it is more commodioufly 
prepared, by dilfolving it in cold water, acidulated 
with vitriolic acid ; in which cafe, the acid quits the 
jelly, and forms with the lime a felenitic mafs, while,, 
at the fame time, the jelly being deprived, in fome- 
meafure, of its moifture, through the formation of 
an indifibluble' concrete amongfl: its parts, foon dries, 
and hardens into a firm body j whence its fuperior 
ftrength and durability are eafily comprehended. 
It has long been a prevalent opinion, that fiur- 
geon, on account of its cartilaginous nature, would 
yield great quantities of ifinglafs ; but, on examina- 
tion, no part of this fifh, except the inner coat of 
the found, promifed the lead; fuccefs. This being full 
of 
