IOWA ACADEMY OF SCIENCES. 
99 
water. It was purified by washing with water, dissolving 
in weak ammonia and filtering to remove any traces of 
the original mother substance, reprecipitating with hydro- 
chloric acid and recrystallizing from dilute alcohol two or 
three times. The yield in the first experiment was 24 per 
cent of theory. Later experiments apparently yielded 
better results, but the resulting quantity of acid was not 
weighed. The pure acid melts at 182-3° C. It is of a 
light yellow color and has no taste. It is slightly soluble 
in hot water, from which on cooling it crystallizes out in 
tufts of radial needles. It is insoluble in petroleum 
ether, sparingly soluble in sulphuric ether, but is very 
soluble in warm alcohol and in dimethyl aniline, benzal- 
dehyde, nitro benzene, toluene, glacial acetic acid and 
glycerine. The acid was analyzed by determining the amount 
of silver in the silver salt which yielded results as given 
below. In the second analysis the silver salt had darkened 
somewhat by being allowed to remain some time in con- 
tact with a solution of silver nitrate during the process of 
manufacture: 
Calculated for AgC 13 H 8 N0 5 I. II. 
A g. 30.09 30.09 30.59 
A portion of the acid was dissolved in dilute ammonium 
hydroxide, the excess of ammonia evaporated off and 
observations made as to the character of the precipitates 
yielded by various metallic salts, with results as follows: 
Copper sulphate light greenish blue. 
Aluminum chloride white. 
Lead nitrate white floculent. 
Manganese chloride white. 
Cobalt chloride light pink. 
Magnesium sulphate white. 
Ferric chloride yellowish white. 
Ferrous sulphate light yellow. 
Cadmium chloride white crystalline. 
Mercuric chloride white. 
Platinum tetrachloride yellow. 
Nickel, calcium, strontium and barium salts yielded no 
precipitate with the dilute solutions used. The solution 
was very dilute, and in some cases would undoubtedly 
have yielded a precipitate if it had been more concern 
