J . xoc. Chem. In&, 1918, 37, 252-255~.)-The method previously described for measuring the rate of decompoaition of certain nitrosoamines by alkalis (ANAIYST, 1916, 41, 22) may be applied for the estimation of the alkalinity of those liquids which, on account of colour or some other reason, cannot be examined by the use of indicators or by electrochemicitl methods. The velocity of evolution of nitrogen from nitrosotriaoetonamine and other similar compounds depends on the concentration of

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... l ions. The rate of evolution of nitrogen is most acgurately followed by pressure readings in the apparatus and by the method described (Zoc. cit.); but for results of less accuracy a much simpler apparatus may be employed, and the volume of the evolved gas measured in a burette instead of reading its pressure. The method has been used for t b estimation of the alkalinity of soap solutions. Nitrosotriacetonamine is suitable for hydroxyl ion concentrations up to 0-05 N a t a, temperature of 30" C. and nitrosovinyldiacetonamine for concentrations up t o 0-4 N a t 40" C. Above these values the velocity constant begins to ~cdrift," but again becomes congfant, so that the former substance can be used' between 0.35 and 1-4 N with both sodium and potassium hydroxides, and the vinyl