On the Existence of Active Oxygen / Thesis Presented for the Attainment of the Degree of Doctor of Philosophy at the Johns Hopkins University

by Edward Harrison Keiser

A simple way to show the presence of carbon in any sample of phosphorus is to burn a small piece of the latter in a small porcelain dish, floating in water under a bell jar fitted with a glass stop cock. After the combustion is over the vessel is allowed to stand some time until the white fumes have entirely disappeared. The gas is then passed through water and finally into baryta water where a precipitate is invariably formed. The air in the bell jar must of course be free from carbon dioxide. As the bell jar is only lifted far enough to permit the introduction of the dish with the phosphorus, and this operation is performed instantaneously, the amount of carbon dioxide thus introduced can only be infinitesimal.

We now made some experiments with the object of determining whether changes in the amount of phosphorus exposed in the bell jar F of our ozonizing apparatus had any effect upon the amount of barium carbonate formed in the wash bottle E. We found that the amount of precipitate is plainly influenced by the rate of passage of the gases, the temperature and the amount of phosphorus exposed, but that if the temperature is between 20 and 25°C, the rate of passage of the air about two or three bubbles per second, and the amount of phosphorus exposed from 20 to 30 grams a slight precipitate is always formed by 10 litres of air, and that 25 to 30 litres give a decided precipitate.

Having therefore demonstrated the presence of carbon in all the specimens of phosphorus at our disposal, and knowing that purified air alone when passed over phosphorus would give a precipitate when passed into baryta water, we next determined whether if carbon monoxide being present in the air passing over the phosphorus, and all other conditions the same, the amount of precipitate is increased. For this purpose parallel experiments under as nearly the same conditions as possible were made one with air alone, the other with air and carbon monoxide. In the first experiment about 25 litres of air were passed through the apparatus, the conditions being carefully noted. The wash bottle containing the precipitate was removed at the end of the operation, instantly stoppered and set aside for comparison.

The water was then removed from the wash bottle D and replaced by fresh distilled water, a new bottle attached in the place of E and after passing about a litre of pure air through the apparatus, the necessary quantity of baryta water filtered rapidly through a plaited filter into the wash bottle.

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.