[ 1^7 ] 



Bergman and myfelf in my'firft effays. But he alfo followed ano- 

 ther method, which preferved him from many miftakes, which 

 was to eftimate the quantity of the ftrongeft acid in a given quan- 

 tity of vitriolic acid, v: z: 240 grains by the quantity of it re- 

 tained during ignition in tartar of vitriolate, and in 24-O grains mu- 

 riatic acid by the quantity retained in muriated tartarin, for in ef- 

 fect thefe acids, as I have found, contain leafL water in thefe com- 

 pounds ; this advantage however he fometimes loft by the decora- 

 pofitions arifing from ignition, particularly in his experiments on 

 metallic fubftances. 



To render this paper ftill more ufefal, I fhall lay before the Aca- 

 demy fome important determinations of the proportion of ingre- 

 dients in compounds of which I had not myfelf treated, and are 

 either not generally known, or fcattered in divers treatifes not-eafi- 

 Iv colleded, to moft of which however I have added my own ex- 

 periments. 



■♦ 

 When alkalies or earths combined with fixed air are diffolved in 

 acids,' though far the greater part of the fixed air is expelled dur- 

 ing the folution, yet fome portion of it is often retained, and may 

 in fome degree alter the fp. grav. of the folution ; this circumftance 

 I did not recoiled till lately; it was firft noticed by Mr. Cavendifl), 

 Phil. Tranf 1766, p. 17a, and afterwards by Bergman in his notes 

 on SchefFer, §. 51, but mqre explicitly by Scheele, Chy. An. 1786, 



