the Attractive 
Powers of Mineral Acids. 
7 1 
Quiefcent affinities. 
Divellent affinities. 
Nitrous acid to filver 
375 
Nitrous acid to copper 
2 55 
Calx of copper to phlogifton 
3 6 3 
Calx of filver to phlogifton 
491 
Sum of the quiefcent affinities 
738 
Sum of the divellent — 
746 
The fclutions muff be nearly faturate, elfe a large quantity 
of the added metal will be diflolved by the free acid, before 
any precipitation can appear; yet it muft not be intirely fatu- 
rate, at leaf! in fome cafes, as will prefently be feen. 
I faid in mojl cafes , becaufe in fome, particularly where mer- 
cury, bifmuth, cobalt, regulus of antimony or arfenic, are 
ufed, another power intervenes which has not yet been fully 
inveftigated, viz. the attraction of calces to each other, which 
J fhall occafionally mention. 
It is worthy of obfervation, that the precipitating metals are 
more dephlogifticated by this means than by direct folution in 
their refpedtive menftruums, and are even diflolved by men- 
ft ru urns that would not otherwife affeft them ; becaufe their 
phlogifton is torn from them by two powers inftead of one 
thus, though copper be diredtly foluble in the vitriolic acid, 
only when this acid is concentrated and heated to a great 
degree, yet if a piece of copper be put into a dilute cold folu- 
tion of filver or mercury in the vitriolic of acid, or even into a 
dilute folution of iron, expofed to the open air, it will be dif- 
folved ; a circumffance which juftly excited the wonder of Air. 
margraaf and Mr. wenzel, who did not apprehend the 
theory of it : and lienee we fee how vitriol of copper may be 
formed by nature, and why it always contains a mixture of iron. 
Of fo lut ions in the vitriolic acid. 
This acid diffolvcs iron and zinc, without the afliftance of 
heat ; becaufe its affinity to their calces is greater than the affi- 
