190 
IOWA ACADEMY OF SCIENCE 
If this latter is treated with alcoholic ammonium sulphide, it 
gives 
C • NH • C6H4 • COONH4 
/ 
S 
C • NH • C6H4 • COONH4 
analogous to henzamide as made from henzonitrile and 
ammonium sulphide. This indicates the nitrile formula. That 
our compound is the cyan acid is also shown by its salts, which 
characterize it as a monohasic acid. 
The ammonium salt has a very hitter taste. The free acid was 
not prepared. When hydrochloric acid is added to solutions of its 
salts, no precipitate appears. Analyses were made for nitrogen 
by the Gunning method, and for sulphur by Pringsheim’s method. 
.2966 g. ammonium salt required 31.19 cc .1084N HCl. 
.1397 g. ammonium salt required 14.83 cc .1084N HCl. 
.2801 g. ammonium salt gave 4 times .0623 and .067. 
Theory for CgHgOgNsS Found 
Nitrogen, 16.21 per cent. 16.11 - 15.95 per cent. 
Sulphur, 12.35 per cent. 12.31-12.24 per cent. 
Sliver Salt of the Cyan Acid. 
NO. • CH3 • CeH, • ON • SO3 • Ag 
The silver salt of the cyan acid was first prepared by adding 
silver nitrate solution to the hot solution of the ammonium salt. 
An attempt was then made to purify the precipitate by dissolv- 
ing in much water, and letting it crystallize slowly. It was found, 
however, that decomposition was likely to take place when boiling 
the silver salt at high dilutions, and so the procedure was 
changed. The very dilute solution of the ammonium salt was 
heated, the silver nitrate solution was added only slightly in ex- 
cess of the calculated amount, and the solution was cooled slow- 
ly. The silver salt precipitated in fairly heavy, pointed needle.s 
which Vv^ere not clustered. When washed with cold wmter, they 
were ready for analysis. The drying should take place in the 
dark if a pure white product is obtained. The silver salt of the 
cyan ac'd is somewhat more soluble than the silver salt of the 
imide, but is still quite insoluble at ordinary temperatures. 
There is no water of crystallization. Silver was determined 
directly. 
