NOTE ON NITRITE OF SODA. 
205 
between the two salts which is sufficient to enable the nitrate to be in great 
measure removed before the nitrite begins to crystallize out. A sample of 
rough nitrite, treated in this way, which originally contained 18-9 per cent, of 
nitrite of soda was purified till it yielded 40-3 per cent. As the crude nitrite 
invariably contains either carbonate of soda, caustic soda, or a mixture of both, 
this method will not alone enable a perfectly pure product to be prepared. 
Dr. Attfield said, some of liis students had succeeded in making crude nitrite of soda 
by fusing nitre with charcoal at a temperature so low that no deflagration whatever 
took place. The product was, however, anything but satisfactory, though, to be sure, 
it was difficult to ascertain its exact value by any method of analysis he knew of. The 
conversion of a nitrite into the ammonia salt, and estimation of the bulk of nitrogen 
evolved from that salt on heating was the most promising process he had tried. 
ON THE PURITY OE COMMERCIAL BROMIDES AND IODIDES 
OTPIER THAN IODIDE OE POTASSIUM. 
BY HENRY MATTHEWS, F.C.S. 
Nineteen samples of bromides and iodides were examined, consisting of seven 
samples of bromide of potassium and three each of the bromides and iodides of 
ammonium and cadmium. The results of the analyses are given in the tables 
annexed. 
BROMIDE OF POTASSIUM. 
I. 
II. 
III. 
IV. 
V. 
VI. 
VII. 
Carbonate 
0-5 
0-45 
o- 
o- 
o- 
o- 
0-25 
Sulphate . . 
0-25 
1-08 
0-87 
0-57 
o- 
o- 
0-51 
Bromate . 
o- 
trace. 
trace. 
o- 
o- 
0- 
trace. 
Chloride . . 
3-28 
5-01 
1-95 
2-83 
o- 
o-7 
2T1 
Iodide . . . 
051 
trace. 
2-11 
3-88 
o- 
o- 
0-04 
Water . . . 
1-69 
0-8 
0-74 
0-96 
0-22 
0-51 
1- 
Bromide . 
93-52 
92-97 
93-86 
91-66 
100-04 
98-71 
95-86 
99-75 
100-31 
99'53 
99-90 
100-26 
99-92 
99-77 
BROMIDES OF AMMONIUM AND CADMIUM. 
i 
Bromide of Ammonium. 
Bromide of Cadmium. 
I. 
II. 
III. 
I. 
II. 
III. 
Carbonate . . 
o- 
o- 
o- 
o- 
o- 
o- 
Sulphate . . 
trace. 
2-99 
o- 
0' 
0- 
o- 
Bromate. 
o- 
0* 
o- 
o- 
o- 
o- 
Chloride. . 
0-44 
0-8 
1-34 
0-73 
0-45 
o- 
Iodide . . . 
o- 
trace. 
o- 
trace. 
trace. 
0- 
W ater 
2-35 
3-08 
1-41 
13-78 
1973 
19-41 
Bromide. . . 
97-46 
92-85 
96-9 
j 86-08 
79-60 
80-38 
100-25 
99-72 
99-65 
100-59 
99-78 
9979 
