In a previous notice* I have pointed out the existence of a new class of nitrogenous acids which are generated by the action of nitrous acid on the amidic acids of the benzoic group, the change consisting in the substitution of one equivalent of nitrogen for three equivalents of hydrogen in two molecules of the amidic acid. C 28 H 14 N 2 O 8 +N O 3 = 3HO + C 28 H 11 N 3 O 3 Under the influence of various agents these new acids undergo remarkable changes, amongst which the transformation produced by the mineral acids deserves to be particularly noticed. If the acid C 28 H 11 N 3 O 8 be gently heated with strong hydrochloric acid, nitrogen gas is evolved, the yellow colour of the original acid disappears, and a red body separates, which may be separated by filtration and purified by treatment with animal charcoal. Both the physical properties and the analysis of the substance thus obtained, prove it to be pure chlorobenzoic acid. The hydrochloric mother-liquor on evaporation deposits crystals of the hydrochlorate of benzamic acid .
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