( 1 8 ) 
9 Drachms, Avoir dup, the former having been weigh’d 
by the fame kind of Weight. 
The Lofs in the Dilfolution and Filtration of the Vi- 
triol and Alum, is not worth taking Notice of, they 
having both been very clean before they were dilfolv’d. 
The Mixtures being made as prefcrib’d, with the Addi- 
tion of the Spirit us Salts , the Produd was a very fine 
Blue, which when well edulcorated by frequent Wafh- 
ings, and after that thoroughly dried weigh’d 3i. or a 
little more, and entirely anfwer’d the Chara&er the 
Author gave of it. 
Among the feveral Experiments that were made with 
thefe Liquors, I mean the Lixivium with Blood, the 
Solution of Vitriol, the Solution of Alum, and the 
Spirit of Salt, tho* they always produced a Blue, yet 
that Blue differ’d in Degrees of Colour, according to the 
varied Proportions of the Vitriol and Alum, and the 
Colours produc’d from thefe feveral Proportions were 
each of them improv'd by the Addition of the Sp. Salts. 
I fhall mention only two of the feveral I tried, in 
one of which the Alum was entirely left out, and a 
pale Blue produc’d } in the other, the Proportions of 
Vitriol and Alum were equal, and a very deep Blue 
was produc’d. 
Thefe Differences in Colour, arifing from the feveral 
Proportions of the Vitriol and Alum, are only men- 
tion’d to confirm the Truth of the Author’s Prefcript, as 
being the moft exad and beft- proportion’d to produce 
the fineft Colour, of any I have try’d. The only Mis- 
fortune he takes notice of, as attending his Prefcript, is 
what may happen in the Calcination. 
It would be curious to know what gave the firft Hint 
for the Produ&ion of fo fine a Colour, from a Combi- 
nation of fuch Materials } efpecially when we come to 
confider, that the Blood has the greateft and principal 
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