the Attractive Powers of Mineral Acids » 3 3 
feveral important procefles are very inaccurately deferibed by 
antient chymical writers, and even by fome of a modern date, 
they frequently, for inftance, deferibe the acid they employed 
by reference to the quantity of fixed alkali, earth, or metal, a 
given quantity of fucli acid was capable of neutralizing or 
cliffolving. Now the foregoing obfervations immediately in- 
form us of the quantity of real acid capable of performing that 
effect ; the remainder, therefore, mu ft have been water ; and 
the quantity of real acid and water being known, the fpecitic 
gravity is eafily found by the help of the foregoing tables, and 
thus an acid of the fame ftrenpth mav be formed. Thus 
O 
sciilut ter, in the belt treatife on E flaying yet extant*', in- 
forms us, that the heft aqua fords for parting fiver from gold 
is that of which a pound diflolves one mark, that is, half a 
pound of fdver : then 1000 grs. of it fhould diflblve 500 of 
Iilver. Now, ' by the foregoing experiments, we find, that 
loo grs. of alloyed iilver require 38 of real acid for their folu- 
tion ; confequently 500 grs. of iilver will require 190 grs.; 
confequently 1000 grs. of fuch fpirit of nitre fhould contain 
190 grs. of real acid and 810 of water. Then recurring to 
the table of the nitrous acid, I find, by the rule of proportion, 
that the fpecific gravity of this acid muft be about 1,261 ; for 
as 190 is to 810, fo is 393 acid to 1675 of water. This pro- 
portion of water is fomewhat greater than that I ufed, but 
schlutter ufes a fand heat. 
adly, The importance of this knowledge in the art of phar- 
macy is very obvious, efpecially with regard to medicines 
formed of metallic fubftances, whole powers depend on the 
proportion of their ingredients, and their a£Uon on each other. 
qdly, This degree of preciiion muff tend confiderably to the 
* Vol. I. p. 332. French edition. 
Vol. LXXI 1 I. F 
improve- 
