560 
Proceedings of the Royal Society 
when dried at 150°, bismuth and oxygen only, and these in the 
atomic proportion Bi 2 0 7 . 
But I subsequently found that the supposed oxide, when heated 
in a closed tube, evolved a little ammonia. I also proved the 
presence of nitrogen by the sodium test. Determinations were 
therefore made of nitrogen and of carbon, the former by burning 
with soda lime, the latter by burning with copper oxide. 
1. 0*7075 grm. gave 0*0285 grm. N. =4*03 per cent.=7*49 per cent, cyanogen. 
2 . 
0*867 
55 
55 
0*0365 
55 
N. 
=4*20 „ =7*80 
55 55 
3. 
1*113 
55 
55 
0*046 
55 
N. 
=4*14 „ =7*69 
55 55 
4. 
0*8275 
5’ 
55 
0*1275 
55 
co 2 
=0*0348 grm. C=0*0754 
grm. CN=9-10 per cent, cyanogen. 
5. 
1*2435 
55 
55 
0*145 
55 
o 
o 
to 
=0*040 „ 0= 0*0866 
55 CN=7-00 „ 
Determinations of water made simultaneously with those of carbon gave 4*60 and 4*75 per 
cent. 
Hence mean percentage of cyanogen = 7*81 
Do. do. of water = 4*67 
The preparation used in these analyses contained 77*25 per cent, 
bismuth. The mean percentage of bismuth, calculated from analyses 
of those preparations which were dried at 120° and contained a 
little water, is 76*80 per cent.; taking this number and 4*67 as 
representing the amount of water in the salt, and determining 
oxygen by difference, the results agree very well with the complex 
formula 4Bi(CN) 3 .5Bi 2 O 5 .10H 2 O. The analytical numbers agree 
fairly well with the formula 2Bi(Cbf) 5 .5Bi 2 0 5 .9H 2 0, which requires 
bismuth 75*40, cyanogen 7*78, oxygen 11*98, and water 4*85 
per cent. 
Found. 
Calculated for 
4Bi(CN) 3 .5Bi 2 O 5 .10H 2 O . 
Bismuth, . . . 76 "80 
76-72 
Cyanogen, . . . 7*81 
8-15 
Oxygen (by difference), 10 "72 
10-44 
Water, . . . 4 "67 
4-69 
100-00 
100-00 
Calculating all the results on the dry salt, numbers are obtained 
which agree better with the formula Bi 7 (CN) 6 0 15 than with any 
other. 
Found. 
Calculated. 
Bismuth, . . . 78 "86 
78-78 
Cyanogen, . . . 8 ‘14 
8-37 
Oxygen (by difference), 13 "00 
12-85 
100*00 
100-00 
