88. An Account of; and 
An ACCOUNT, &. 
pelea led to the difcovery of thefe 
Colouts, which it is to be hoped will be 
found ufeful in the art of painting. ‘Two of them 
have fomething of the appearance of Pruffian blue, 
but from the following inveftigations there feems 
to be fome other principle befides Phlogifticated 
Alcali for their bafis; which I muft confefs I am 
not able to account for, but leave it to the judgment 
of Gentlemen of greater abilities than I can pretend 
to. : 
After I had extracted all the Chryftals of Soda. 
Phofphorata from a combination of the Phofphoric » 
Acid with pure mineral Alcali, or with the bef 
Spanifh Barilla freed from as much common falt as 
poffible, I generally threw away the Mother-waier 
as ufelefs, which being poured through an iron 
grating, fome of it was feattered about, and ap- 
peared of a blueifh colour on the contiguous ftoness 
upon which appearance, imagining it to proceed 
from a Phlogifticated Alkali, I diffolved four ounces 
of common alum and one ounce of martia! vitriol 
- in two quarts of wter, by boiling them togethers 
On fome of the Mother-water of Soda Phofphorata 
was poured a little of the alum nous and martial 
folution: at firft a greyifh coagulum only was 
formed ; 
