TROPY.) In 1783 Van Marna' observed that oxygen gas through which an electric current had been passed, as well as the air or oxygen in the vicinity of an electric machine, possessed a pecu liar odor somewhat resembling chlorine. lle re ferred to it as the 'smell of electricity.' In 1801 Crnikshank observed a similar odor when water was decomposed by electrolysis. SehiMbein. in 1840. invest igated the matter and established the fact that the odor was due to the formation of new gas, which he named ozone. Ile showed that ozone was generated by the action of phospho rus on moil air, and that it was capable of liberating iodine from potassium iodide. Its con stitution was a matter of doubt until Soret deter mined the fact that it was an allotropic form of oxygen produced by the condensation of three volumes of oxygen into two of ozone. It is found in minute quantities in the atmosphere, of which it is regarded as a normal constituent, and its presence is believed to be due to the electric discharges during thunder storms, silent dis charges from thunder clouds, vibrations of water, especially of saline waters, as in sea foam, and the action of some vegetable prod ucts on the air. Ozone is also said to be formed by the action of sunlight on clouds and the blue ness of the sky has been attributed to its presence. Ozone is formed when a series of electric sparks is passed through oxygen or air, and it is evolved at the positive pole in the elec trolysis of acidulated water. The slow oxidation of phosphorus in air yields ozone, and it may also he obtained by the action of strong sulphuric acid on barium peroxide. Certain organic sub stances, such as turpentine, various essential oils, etc., generate ozone when exposed to the air.
Ozone is a gas with a strong penetrating odor resembling that of diluted chlorine. When con densed under a pressure of 125 atmospheres at —103° C., it forms a deep blue liquid. It is more strongly magnetic than common oxygen. It decomposes slowly even at ordinary tempera tures. It is a very strong oxidizing agent, con verting copper, mercury, silver, and iron into their oxides. It oxidizes most organic com pounds, destroying rubber and vulcanite with great rapidity; also it bleaches many colored vegetable and animal products, such as indigo, litmus, blood, etc. Its powerful oxidizing prop erties are taken advantage of for commercial purposes and its artificial production for the pur pose of purifying the air of sick-rooms has been recommended. It finds sonic application for bleaching, as in the case of discolored engravings, where the printed portion is rolled up and in serted in a glass vessel, on the bottom of which some water and pieces of phosphorus have been placed. It has also been used to oxidize alcohol to aldehyde and to vinegar, and for the rapid aging of liquors. Slightly ozonized air and oxy gen are used medicinally, especially in pulmonary complaints, although if too strong it is said to produce harmful effects, causing headache and irritating the mucous membranes of the respira tory organs.
sixteenth letter in the English alphabet. It can be traced through the Latin and Greek alphabet to the Semitic pe, 'mouth,' probably so called from the originally elliptical shape of the letter. The form of the letter is now esentially Roman, which differed from the Greek in that the second stroke was bent round to meet the first.