[ 72 ] 
a lower heat than Bergman, and it is certain that Wiegleb 
conftantly applied a red heat. 
Seconp-y, In a paper on the attractive powers of acids, inferted 
in the tranfactions of the Royal Society for 1783, I obferved 
that the characteriftic mark of /aturation confifted in the 
lofs of fome peculiar property of the faturating bodies, and 
that xeutralization exprefled the faturation of each of the 
combined principles; as an inftance of the firft I adduced 
the cafe of the faturation of an acid, which is judged to 
take place when it lofes the property of reddening certain 
vegetable blues, this being the teft univerfally applied and 
admitted in this cafe. This inftance Mr. Morveau thinks 
not fufficiently precife, for in this fenfe he thinks there 
fhould exift combinations without faturation, which is repug- * 
nant to the principles of affinities, and contrary to obfer- 
vation; thus, fays he, “ there is a precife term for the com- 
“ bination of a concrete acid with water, and of a concrete 
“ acid with a fluid acid, and yet the property of affecting 
“ colours is far from being effaced.” As to the firft inftance, 
I do not think that an acid can be faid to be faturated with 
water (an expreffion indeed very unufual) as long as it retains 
its tinging property ; and as to the fecond, I confefs I am not 
acquainted with the effects of the affinities of acids to each 
other. 
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