4* ©f tfle ^ec&am'cal 0);fgftte of 

 EXPER. xx. 



TO (hew, how much the Efficacy* 

 of a Menftruum may depend 

 even upon fuch feemingly flight Me- 

 chanical Gircumftances as one would 

 not eafily fufpeft any neceffity of, I 

 fhall employ an Experiment 5 which 

 though the unpra&is'd may eafily 

 fail of making well , yet, when I 

 tried it after the beft manner 5 I did 

 it with good fuccefs. I put then up- 

 on Lead a good quantity of well 

 rectified Aqua Fortis , in which the 

 Metal, as 1 expe&ed, continued un- 

 diflblved 3 though, if the Chymifts 

 fay truly that the difTolving power 

 of the Menftruum confifts onely in 

 the acid Salts that it abounds with, 

 it feems naturally to follow, that the 

 more abundance of them there is 

 in a determinate quantity of the Li- 

 quor, it (hould be the more power- 

 fully 



