OF LIQUIDS IN VAPOUR. it 



this account the heat would not be communicated fo 

 fpeedily, and confequently fome would be loft. But 

 the difference in this cafe was only that of 1.6 and 1.5. 



7. Experiments relating to aqua regia and the fclution 

 of gold and platina in it. 



In impregnating marine acid with nitrous vapour, 

 which makes an aqua regia much ftronger than that 

 which is made by a mixture of two acids, there drop- 

 ped from the end of the tube through which the phlo- 

 gifticated vapour was conveyed a deep green acid, in 

 the form of balls, which fell to the bottom of the veffei, 

 and after continuing a fhort time burft with the emifiion 

 of air, the green colour then difappearing and the acid 

 gradually affumlng its proper orange colour. 



Going to make ufe of a quantity of aqua regia that had 

 been made fome months, I found its colour changed, 

 and that, by the efcape of the nitrous vapour, it was 

 become mere marine acid. Impregnating it again with 

 nitrous vapour, it was the fame as before. Diftilling 

 the folutions of gold and platina in this compound acid, 

 the liquor that came over was marine acid. Platina re- 

 quired more heat to diflblve it than gold. 



8. I made the following experiments to obferve the 

 different effefts of phlogifticated and dephlogifticated ni- 

 trous acid in the folution of mercury. 



In the dephlogifticated acid an ounce of mercury gave 

 lefs of both nitrous and dephlogifticated air. I diffolved 

 an ounce of mercury in dephlogifticated acid of nitre, 

 and without changing the retort, which w^is cooled, 

 and gradually expofed to a red heat till nothing more 

 came over, I got about 15 ounce meafures of nitrous 

 air, and 55 of dephlogifticated. From the calx: that was 

 fublimcd I got 17 ounce meafures of dephlogifticated 

 air. In the fame procefs with phlogifticated nitrous acid 

 1 got 43 ounce meafures of nitrous air, and 63 of de- 

 B 2 phlogifticated ; 



