Closely related to these experiments of Baumann are those of Professor Remsen[19] on the transformation of ozone into oxygen by heat. Now if atoms of oxygen can exist in the free state, it is difficult to see why transformation some of the oxygen atoms should not be in the free condition, and the statements of Baumann being true, if carbon monoxide is also present this should be oxidized. To test the question a gasometer was filled with carbon monoxide made from potassium ferrocyanide and sulphuric acid. Before entering the gasometer the gas was purified by passing through four wash bottles containing concentrated sodium hydroxide. Another gasometer was filled with pure oxygen. The ozone was produced by the silent electric discharge in a Wright’s tube connected with a Stoltz electrical machine. In detail the experiments were conducted as follows:-- A slow current of oxygen from the gasometer was passed through three woulfe bottles containing a concentrated solution of caustic soda and then into the ozonizer, the ozonized oxygen was then passed into a U tube, rubber joints between the ozonizer and U tube were found to be rapidly perforated and were replaced by a device of this kind:-- [Illustration] A, the tube from the ozonizer was introduced several inches into B, the tube leading to the U tube, and the joint C was closed by a cement composed of beeswax and paraffin. The carbon monoxide was passed through wash bottles containing caustic soda and finally through baryta water. The two gases were then brought together in a U tube placed in an air bath. After leaving the U tube the gases passed through perfectly clear lime water. Under these conditions the current of the gases was continued for an hour, and no precipitate was formed in the lime water. “Separate experiments were made for the purpose of determining how readily the ozone was destroyed, and it was found that, even when the thermometer in the U tube indicated a temperature considerably below that stated as the decomposition temperature of ozone, and when highly ozonized oxygen was certainly entering the U tube, no ozone passed out, whether carbon monoxide was present or not in the tube at the same time.” The experiment as thus described was repeated several times, but always with the same result. “One modification of the experiment should also be mentioned in this connection. In order to get as good ozone as possible the ionizer was filled with oxygen and the current of gas stopper, the silent discharge was allowed to continue for a few minutes, then the gas was slowly passed into the heated U tube containing carbon monoxide. This interrupted current of oxygen was continued for about an hour but no oxidation of carbon monoxide to dioxide could be detected.” The conclusion that must necessarily be drawn from the result is that if carbon monoxide is a test for active oxygen, then when ozone is decomposed by heat there is no nascent or active oxygen formed.