8 On the transmission 



2. Of the produclion of fidphur by heating water ini' 

 pregnated zv'itb vitriolic acid air. 



When 1 firft made this experiment it was a long time 

 before any fiilphur appeared ; but it is formed much 

 fooner when the common air is expelled from the tube 

 by heating a little of the impregnated water previoufly 

 to its being hermetically fealed. By this means the ful- 

 phur will appear the firft day, and in three or four days 

 the produdion will have attained its maximum, the 

 whole tube being covered with white cryftals. After 

 fome days there will be a little ball of yellow fulphur 

 fwimming on the middle of the liquor, and a good deal 

 of fulphur will be found at the bottom of it, by the cry- 

 ftals on the fides continually Aiding down into the liquor, 

 as others are formed. The tubes I have generally ufed 

 for this purpofe are fomething more than three feet long, 

 and more than half an inch wide. 



Sulphur is produced in the very fame manner and in 

 the fame time by means of water impregnated with he- 

 patic air. The only difference that I obferved was that 

 I did not fee the fame dancing vapour in this procefs as 

 in that with vitriolic acid air, which is a curious circum- 

 ftance in the experiment. 



Having evaporated to drynefs a quantity of water im- 

 pregnated with hepatic air, there remained a black pow- 

 der, like ethiops mineral. When this faturation is made 

 with water confined by mercury, it has a white colour. 



Opening a tube in which fulphur had been formed 

 from water impregnated with vitriolic acid air under wa- 

 ter, I found the air within it of the ftandard of 1.6, 

 without fixed air, or any thing inflammable in it. 



3. An experiment with Pa pin s Digcjier. 



Aided by heat in this inftrument a folution of cauftic 

 alkali made a liijuor filicum with pounded flint glafs. 



4. Of 



