Even when the ratio of Cl:NH_{3} was 4:1 by weight, practically the same as was used in the experiments of Noyes and Lyon, and Bray and Dowell, quoted above, the germicidal action was totally destroyed and the 24-hour results showed aftergrowths which were somewhat proportional to the amount of ammonia added. This was probably due to the formation of ammonium chloride, which provided additional nutriment for the organisms. It has often been assumed that hypochlorite solutions are decomposed on addition to water containing free or half-bound carbonic acid with the production of free chlorine, but no evidence has been adduced in support. Free chlorine can be separated from hypochlorous acid in aqueous solution by extraction with carbon tetrachloride and when this solvent is shaken with a carbonated hypochlorite solution it is found that only traces of chlorine are removed. Hypochlorous acid reacts with hydrochloric acid with the evolution of free chlorine HClO + HCl = Cl_{2} + H_{2}O but in very dilute solution the amount of free chlorine formed is exceedingly minute. Jakowkin[10] has shown that this reaction does not proceed to completion and that the concentration of free chlorine can be calculated from the equation HClO × H^{.} × Cl' = 320Cl_{2} in which the reactions are expressed in gram molecules per litre. The hydrogen ions and chlorine ions are obtained from the dissociation of carbonic acid (H_{2}CO_{3} <=> H^{.} + HCO_{3}') and chlorides (NaCl <=> Na^{.} + Cl') and also by the dissociation of hydrochloric acid produced by the interaction of hypochlorous acid and organic matter. HClO = O + HCl <=> H^{.} + Cl'. If the formula of Jakowkin can be correctly applied to solutions containing fractions of a part per million of hypochlorous acid the free chlorine liberated by the addition of 1 p.p.m. of bleach to a water low in chlorides would be of the order 10^{-7}-10^{-8} p.p.m. _Sodium hypochlorite_ is probably hydrolysed in dilute solution in a manner similar to that of bleach. 2NaOCl = NaCl + NaOH + HClO. For solutions containing equal amounts of available chlorine, electrolytic sodium hypochlorite is more dissociated than bleach because of the absence of an excess of base, and this, together with the presence of sodium chloride, accounts for the slightly higher germicidal velocity obtained. The experience of pulp mills, with bleach and electrolytic hypochlorites, confirms this: the latter is a much quicker bleaching agent than bleach and it is often so rapid as to make it desirable to reduce the velocity by the addition of soda ash.