227 
day time, when they are actively snp in absorbing nourishment aud 
replacing wasted tissue with new mater 
f the different materials used in irent rp the gas, the most 
important is the potassium cyanide; of this there are three grades: 
the mining cyanide, commercial cyanide, and the C.P. (chemicall 
pure). Of these three brands, the mining cyanide is wholly Nm 
for the production of the gas, and the C.P. is too expensive; the 
commercial brand (fused) is the only one that is used for уан the 
1 m 
utmost importance that the operator should know the exact per-centage 
of pure potassium cyanide that his cyanide contains, and when large 
quantities of it are purchased at one time it would be advisable to obtain 
one or more analyses of it by a reliable analytical chemist ; or if it 
not possible to submit the cyanide to such person, an analysis ‘of it could 
be made by almost any person accustomed to the use of chemicals 
or drugs. 
“ The only substance required for this purpose is the crystals of nitrate 
of silver (Ag NO ), which may be obtained в almost апу — € 
drug store. Dissolve the nitrate in cold water contained in a glass 
or earthen vessel, using one-fourth of an ounce e (ran of the crystals ч 
one pint of water; this dissolves in a few minutes, forming a whitish, 
semi-transparent solution. The с anide, when dissolved in water, 
orms a transparent, nearly colourless solution; when a small quantit; 
of the nitrate of silver solution is added to this it at first spreads out in 
a white cloud, like milk, but it soon breaks up into small, white 
pieces ich ually disappear upon being agitated, р ы the 
solution nearly as trans t as at first; when more of t 
silver solution is added from time to time the тем er is d, 
added to the cyanide solution the latter immediately becomes white and 
opaque, like к, completely concealing from view the bottom of the 
vessel containing it. This completes the operation, and the quantity of 
nitrate of Komm, solution used will indicate the strength of the cyanide © 
tested. "When absolutely pure, 5 grains of the "potassium cyanide 
i i i i uid ounce of the above nitrate of 
silver pri before the turbidity occurs, indicating that the cyanide is 
100 per strong; if only one-half of a fluid ounce of the nitrate 
hand it аы а reddish or black stain, which can ndr be removed 
by washing the stained part in a solution of cyanide and water ; this 
will quickly remove ee stain without causing any injury to the parts 
precei, except, of course, when the stains occur upon a sore or cut 
n the han d, in which n it would be dangerous to apply the — 
o these places. 
“Tt sometimes happens that the per-centage of cyanogen (CN or Cy) — — 
is given, instead of the per-centage of potassium — — ar KOy) p 
but in cases of this kind the per-centage of cyanide can be readily ascer- - 
