30 Mr. kir wan's Experiments and Obfervations on 
heat of iio°. The folution, however, becomes turbid in a 
few days. 
The calces of antimony are foluble in a much lefs degree. 
Regulus of antimony in marine acid. 
icogrs. of fpirit of fait, whofe fpecific gravity is 1,220, diffolve 
about 1 gr. of regulus, with the affifbnce of a flight heat. Spirit 
of fait, whofe fpecific gravity is 1,178, alfo a£ts upon it, but 
diffolves ftill lefs. I believe the concentrated acid would, in a 
long time, and with the help of a gentle heat, diifblve much 
more of it. 
The cakes of antimony are much more foluble in this acid. 
Regulus of arfenic in vitriolic acid. 
200 grs. of oil of vitriol, whofe fpecific gravity is 1,871, 
diifblve 18 of regulus of arfenic in a heat of 250°. Of thefe 
about 7 cryftalize on cooling, and are foluble in a large quan- 
tity of water. 
The calces of arfenic are more foluble in this acid. 
Regulus of arfenic in nitrous acid. 
100 grs. of this femi-metal require 140 grs. of real nitrous 
acid, whofe proportion to water is as 1 to 1 r, and the affiftance 
of heat. It is foluble in a lefs or more concentrated acid, but 
in a leffer degree. This folution affords '102 cubic inches of 
nitrous air. The barometer at 30, and the thermometer at 60. 
The calces of arfenic are alfo foluble in this acid. 
Regulus of arfenic in marine acid. 
100 grs. of fpirit of fait, whofe fpecific gravity is 1,220, 
diffolve if grs. of regulus of arfenic; the marine acid, in its 
common 
