In studying the liquid phase thermal reaction, some 70 tubes from 12 different manifold fillings were prepared and analyzed. Experiments were done at 180, 200, 210, 220 `. Following observation of the fact that the reaction rates of supposedly identical reaction mixtures prepared on the same filling manifold and exposed under identical conditions often differed by several hundred per cent, a systematic series of experiments was undertaken to see whether the difficulty could be ascribed to the method of preparing the chlorine, to the effects of oxygen or moisture or to the effect of surface to volume ratio in the reaction tubes. In addition to the method described in the section above, chlorine and radiochlorine were prepared by the electrolysis of a ** f eutectic on the vacuum line, and by exchange of ** f with molten ** f. Calcium hydride was substituted for ** f as a drying agent for carbon tetrachloride. No correlation between these variables and the irreproducibility of the results was found.

The reaction rates observed at 200 ` ranged from ** f of the chlorine exchanged per hour to 0.7 exchanged per hour. In most cases the chlorine concentration was about ** f. Sets of reaction tubes containing 0.2 of an atmosphere of added oxygen in one case and added moisture in another, both gave reaction rates in the range of 0.1 to 0.4 of the chlorine exchanged per hour. No detectable reaction was found at room temperature for reaction mixtures allowed to stand up to 5 hours.