The author, in 1915, during a series of experiments on the relative germicidal action of hypochlorites, attempted to prepare the ammonium salt by double decomposition of bleach and ammonium oxalate solutions. Ca(OCl)_{2} + (NH_{4})_{2}C_{2}O_{4} = CaC_{2}O_{4} + 2NH_{4}OCl. The velocity of the germicidal action of the solution was found to be about ten times greater than the germicidal velocities of other hypochlorites of equal concentrations, (Race[3]), and from a consideration of the chemical formula of ammonium hypochlorite it appeared probable that it would be very unstable and decompose into chloramine, which Rideal had previously shown to have an abnormal germicidal action, and water. NH_{4}OCl = NH_{2}CL + H_{2}O. After these results have been confirmed, the effect of adding ammonia to bleach solution was tried and it was found that 0.20 p.p.m. of available chlorine and 0.10 p.p.m. of ammonia produced equally good results as 0.60 p.p.m. of chlorine only. Similar results were obtained on the addition of ammonia to electrolytic hypochlorite. Experiments made with a view to determining the most efficient ratios of ammonia gave very surprising results: chlorine to ammonia ratios (by weight) between 8:1 and 1:2 gave approximately the same germicidal velocity.[3] The action of the ammonia on the oxidising power of bleach, as measured by the indigo test, was also found to be disproportionate to the amount added. The oxidising action of various mixtures of bleach and ammonia as measured by the rate of absorption of the available by the organic matter in the Ottawa River water is shown in Table XXV. TABLE XXV.--RATE OF ABSORPTION OF AVAILABLE CHLORINE --------------------------+----------------------------------- Ratio Chlorine / Ammonia | PERCENTAGE OF ORIGINAL FOUND AFTER by Weight. +-----------+-----------+----------- | 10 Mins. | 4 Hours. | 20 Hours. --------------------------+-----------+-----------+----------- Infinity (ammonia absent) | 66.8 | 40.0 | 25.1 8:1 | 83.2 | 77.8 | 67.3 4:1 | 97.2 | 94.7 | 88.5 2.7:1 | 98.3 | 96.5 | 92.8 2:1 | 99.8 | 98.2 | 96.2 --------------------------+-----------+-----------+----------- The 8:1 ratio caused a marked reduction in the rate of absorption of the chlorine whilst a 4:1 ratio was almost as active as the ratios containing more ammonia.