Excerpt from Chemical News and Journal of Industrial Science, 1901 If the sulphite be added slowly from a burette a liquid coloured brown by free iodine is obtained when the solid has entirely disappeared; the end-point of the reaction is then easily seen by the disappearance of the colour, or starch paste may be used as an indicator. The hydriodic acid produced can afterwards be estimated in one of several ways; the most convenient, and the one usually adopted, is to titrate the clear solution with standard silver nitrate, using the blue ao-called iodide of starch as indicator (pisani, Annal. D. The aaual operation is carried out as follows - Nitrogen iodide prepared in any one of the ways previously de scribed (chem. News, lxxxii., p. Is rapidly filtered off through asbestos by the aid of a pump. And thoroughly washed with decinormal ammonia, and finally, once with water. A number of 250 c.c. flasks having been prepared, about - o'5 grm. Of the moist iodide is placed in each with about 25 c.c. Of water, and titrated as rapidly as possible with decinormal sodium sulphite, shaking gently the while. The estimation of hydriodic acid by silver nitrate is then carried out in the ordinary way. Light must be rigorously excluded while washing and trans ferring the nitrogen iodide to the flask, and during the titration until all solid particles have disappeared. In the tables where the results are recorded the amount of reducing agent oxidised is stated in the second line, that of the hydriodic acid produced in the third, while in the fourth is the ratio between the reducing agent oxidised and the hydriodic acid produced, calculated to the third decimal place. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.