Now the experiment was repeated, with the difference that during the passage of twenty-five litres of air, a very slow current of carefully purified carbon monoxide (made from pure sulphuric and formic acids) was passed through three wash bottles, like those used for the air, and containing the same substances, and then into the bell jar containing phosphorus and air. The rate of the current was so regulated that during the time of the experiment, which varied in different cases from three to eight hours, three litres of carbon monoxide were used. The same slow formation of a precipitate was noticed when the carbon monoxide was used as in the case of air alone. At the end of the operation we were unable to distinguish any difference between the amounts of the small precipitates formed. They did not appear to be as great as that found by Baumann, they were too small to permit of accurate filtering and weighing, if we consider the nature of the liquid in which they were present. The only conclusion which we can draw is, as is stated in the first paper on this subject, that carbon monoxide is not oxidized by air in the presence of moist phosphorus. That in our first experiments we did not obtain evidence of the presence of carbonic of phosphorus is due to the fact that we worked with small volumes of the gases. In those cases in which relatively large volumes were used the slight cloudiness produced was disregarded as the same result was obtained with air alone. Having, therefore, been unable to obtain any evidence of the oxidation of carbon monoxide when phosphorus undergoes slow combustion in the presence of air and water, the second and last of Baumann’s arguments for the existence of active oxygen becomes untenable. Whether oxygen ever does occur in the so called active condition still remains to be shown. That the nascent state of an element should be due to the momentary existence of free atoms is entirely hypothetical. Tommasi[31] has shown that the properties of nascent hydrogen vary according to the method by which it is formed. He regards nascent hydrogen as ordinary molecular hydrogen plus varying quantities of heat, and he shows that as the heat of the reaction varies so the activity of the hydrogen varies. The same is undoubtedly true of oxygen, for it is known that oxygen evolved by some reactions is more powerful than by others. That we shall ever be able to show that this heat in some cases is sufficient to dissociate the molecules of oxygen seems improbable. Baumann[32] has recently published another paper, but has failed to contribute either new facts or ideas on the subject. Estimation of Carbon in Phosphorus.