Aquarium, 97 
stances poisoned have been left to putrefy, some sulphuret of 
arsenic is formed at the expense of the sulphuretted hydrogen, 
and this, as is well known, escapes detection by Marsh’s appara- 
tus. Sulphuret of arsenic also forms when the'suspected matters 
are carbonized by the action of sulphuric acid after the process of 
Flandin and Danger. The sulphuret of arsenic may be extracted 
by washing the carbonized mass with ammonia; this dissolves 
the sulphuret; then convert the arsenic into arsenic acid (AsO) 
by means of boiling nitric acid, so as to obtain a second solution ; 
t 
u i ie . 
arrington, on what is called the organic equilibrium for waters, 
ve progress of science. 
SEConD SERIES, VOL. XXV, NO. 73.—JAN., 1858. 
: 13 
