These statements remained unquestioned for a number of years and are found in the text books of the period, (for example Graham-Otto, and Gorup-Besauez) but in 1870 Engler and Nasse[10] undertook a thorough investigation to determine whether antozone existed. By treating barium dioxide with strong sulphuric acid they find a gas to be given off which is a mixture of ozone and hydrogen dioxide, and they also show that the stronger the acid the greater the quantity of ozone produced. Secondly, Meissner had stated that by the electrification of oxygen ozone and antozone were formed. The evidence of the existence of antozone being this; when the ozonized oxygen was passed through a solution of potassium iodide to destroy the ozone, the residual gas gave white fumes when brought into contact with water, and after a time hydrogen dioxide could be detected in the water. Schönbein and Meissner held that the ozone having been destroyed by the potassium iodide the antozone passed on and oxidized the water to hydrogen dioxide. Now Engler and Nasse show that when ozone is decomposed by easily oxidisable substances in the presence of water hydrogen dioxide also is formed, and it was the vapor of this compound which had been regarded as antozone. It is known that ozone cannot oxidize water, but that it is to a slight extent oxidized when other oxidisable substances are present is not surprising, as other phenomena of a similar kind are known. Thus when nitric acid acts on an alloy of silver with gold or platinum, containing a certain proportion of silver, some of the gold or platinum are dissolved although by themselves they are insoluble. When ammonia burns some of the nitrogen as well as the hydrogen is oxidized. Engler and Nasse therefore conclude that there is no basis for the assumption of a third form of oxygen having the properties attributed to antozone. Berthelot[11] and Houzeau[12] conclude from their investigations that the oxidizing properties which turpentine and other organic compounds acquire under certain conditions is due to the formation of unstable oxygenated compounds which readily decompose giving up oxygen. Fudakowski[13] has described experiments showing that benzene can become active, i.e. acquire oxidizing properties, but states that he is unable to explain the phenomenon. Loew[14], however, believes active turpentine to contain atomic oxygen or antozone in solution.