of Edinburgh, Session 1881 - 82 . 
565 
found that the various preparations when mixed contained about 
0*25 per cent, cyanogen (mean of three determinations — two of 
nitrogen, and one of carbon). The salt after drying at 100° is anhy- 
drous. The analytical results are collected in the following table : — 
No. 
Mode of Preparation. 
Temp. 
at 
which 
Salt 
was 
Dried. 
Percentage of 
Bismuth 
Found. 
Mean 
Per- 
cent- 
age of 
Bis- 
muth. 
Mean 
Per- 
cent- 
age of 
Oxy- 
gen. 
® go O 
bp $ -T 
cs o cq 
■S * a 
<3 ® 3 
g .5 o 
tu '4-1 
Pi £ o 
S fcJO w 
>> o3 
Propor- 
tion of 
Bi 2 0 3 : 
excess 
of O. 
I. 
Addition of KCN to" 
Bi in HN0 3 , and 
"boiling precipitate 
in concentrated 
KOH, . 
>- 
100° 
88-59; 89-05 
88-82 
11-16 
0-91 
117; 1-1 
II. 
Similar to No. I., ’but'' 
precipitate bv 
KCN boiled with 
very dilute H 2 S0 4 
before treatment 
with KOH, . 
- 
100° 
88-34; 8873 
88-53 
11-47 
1-22 
117; 1-5 
III. 
KCN to Bi3N0 3 in di-1 
lute HN 0 3 ,and sub- 
sequent boiling pre- ( 
cipitate with KOHJ 
100° 
88-43 
88-43 
11-57 
1-32 
117; 1-6 
IV. 
Nos. I, II., and III. 
mixed, again boiled 
with KOH, &c., . , 
160° 
f88-59;8872;-) 
l88-81;88-90;J 
8875 
11-25 
1-00 
117; 1-3 
Mean of Means. Calculated for Bi 4 0 7 . 
Bismuth . . . . = 88 '64 88 '24 
Oxygen . . . . = 11 '36 1176 
Oxygen in excess over Bi 2 0 3 = I'll 1 '65 
Bi 2 0 3 : excess of 0 . . = 117; 1 '4 117 ; 1 '9 
The best method of preparing this salt is to boil a solution of bismuth 
nitrate in the minimum quantity of dilute nitric acid, with three or 
four times its weight of potassium cyanide dissolved in a little 
water, to add a considerable excess of potash, and to continue boil- 
ing for some time ; to pour off the red liquid and boil again with 
potash as long as the liquid becomes coloured, to wash with hot 
water till the washings are quite free from alkali, and to dry at 
about 150°. 
This salt is quite unacted on by hot potash. 
