126 ESSAY VI. 



to be muriated silver. If the acid liquor be then distilled 

 off, muriatic acid goes over, which contains arsenic ; for, 

 when mixed with a little nitrous acid, and again abstracted, 

 a little acid of arsenic remains behind. Hence it follows 

 that the muriatic acid attacked the earth of silver during 

 the digestion, while the acid of arsenic attacked its 

 phlogiston ; whence the arsenic was produced which the 

 muriatic acid afterwards took over with it into the receiver. 



SECTION XXV. UPON QUICKSILVER. 



(a) Quicksilver was not acted upon by the acid of 

 arsenic during digestion. I next put the mixture into a 

 retort, abstracted all the watery part, and then increased 

 the fire. The mass grew yellow, quicksilver rose into the 

 neck, with a little arsenic, and a little yellow sublimate. 

 The fire was then increased till the retort was near melting, 

 but the mass would not enter into fusion. Of 6 drms. of 

 quicksilver which I took for this experiment, I obtained 

 3J drms. in the receiver. Thus the acid of arsenic con- 

 tained 2J drms. of fixed quicksilver. (b) After the retort 

 was cold, I took the mass, which was a little yellow, out of 

 it, and divided it into two parts. One I boiled in distilled 

 water, but none of it was dissolved. Diluted nitrous and 

 vitriolic acids had hardly any effect upon it, but muriatic 

 acid dissolved it very readily. This solution being evaporated 

 to dryness, then put into a retort and distilled, corrosive 

 sublimate rose into the neck. The residuum flowed upon 

 applying a strong fire, and proved to be acid of arsenic. The 

 other portion I mixed with two parts of common salt, 

 and distilled it. Corrosive sublimate rose into the neck of 

 the retort, (c) Calcined quicksilver and arsenical acid being 

 reducible by heat without any addition of phlogiston, this 



