506 
DR. PLAYFAIR ON THE NITROPRUSSIDES, 
II. 13‘34 grs. gave 9’74 grs. carbonic acid and 1*58 gr. water. 
III. 14*475 grs. gave 10*68 grs. carbonic acid and 1*67 gr. water. 
IV. 6*730 grs. gave 5*33 grs. carbonic acid and 1*01 gr. water. 
From barium salt. 
From ammonium 
By action of 
( 
A ^ 
salt. 
caustic soda. 
I. 
II. 
III. 
IV. 
Iron . . . 
19*00 
19*12 
19*38 
19*30 
Sodium . . 
* . • 
15*37 
15*00 
14*72 
Carbon . . 
• . • 
19*91 
20*12 
21*59 
Hydrogen. . 
. . . 
1*31 
1*21 
1*65 
Nitrogen . . ' 
Oxygen . . J 
. . . . 
44*39 
44*29 
42*74 
100*00 
100*00 
100*00 
It will be seen from these analyses that the excess of iron still remains, and this is 
further confirmed by silver salts again made from them and analysed. It will also 
be observed that in specimen IV. we have the same remarkable increase in carbon as 
observed in the barium salt ; the sodium is to the carbon as I : 5^, which is exactly 
the proportion found in the latter salt ; but this excess of carbon does not go down 
with a silver salt made from it. 
Examination of the Silver Salts made from the altered Nitroprussides, 
24. To save unnecessary repetition, the numerous analyses made of the silver salts 
are here brought together, although it might have been more distinct to have intro- 
duced them under the respective salts from which they were made. The reason for 
converting them into silver salts was, that from the high atomie weight of silver and 
its accuracy of determination, the atomic accordance or disagreement between it and 
the iron could more readily be perceived. 
Analyses I. II. and III. were made on three different preparations of silver salt 
made from three different specimens of crystallized nitroprussic acid, by adding the 
latter to nitrate of silver. 
Analysis IV. was made upon a portion of II. treated on sand-bath with strong 
nitric acid in the hope of dissolving out the excess of iron. A very small quantity of 
iron was detected in solution by prusside of potassium. 
Analysis V. was made on the silver salt prepared from crystallized nitroprusside 
of ammonia. 
Analyses VI. and VII. from silver salt precipitated from crystallized nitroprusside 
of barium, which contained 17‘96grs. of carbon, or in which the barium was to the 
carbon as 1 : 5^. 
Analysis VIII. On previous silver salt digested on the sand-bath with strong 
nitric acid to dissolve out excess of iron. 
Analysis IX. On silver salt made from the crystallized sodium salt (No. 2) con- 
taining 19*91 grs. carbon. 
