Chlorimetry, a process chiefly designed to estimate the commercial value of bleaching powder. As this value depends upon the quantity of chlorine which can be liberated from the powders by an acid, Gay-Lussac proposed to estimate the value by measurement of the bulk of a solution of indigo of known strength which a given weight of the chloride is able to deprive of its blue color; and subsequently he determined the amount of available chlorine by the quantity of a standard solution of arsenious acid which could be converted by a known weight of the bleaching powder into arsenic acid. A still more convenient plan has been described by Graham. It depends upon the determination of the quantity of a ferrous salt which a given weight of bleaching powder, in the presence of an excess of acid, can convert into a ferric salt. To perform the operation, a tall narrow tube, called a burette, capable of holding 1,000 grains of water, and graduated into loo equal parts from above downward, is employed.