Page:The American Cyclopædia (1879) Volume XII.djvu/791

 OZONE 777 one, leaving a space between the two, through which a current of pure dry oxygen is passed. This becomes electrified by induction by con- necting the two coatings with the terminal wires of an induction coil. It is said that by this means from 10 to 15 per cent, of the oxygen may be converted into ozone. Schon- bein regarded ozone as permanently negative oxygen, and he also entertained the opinion that there was a permanently positive oxygen, which he termed antozone. The idea of the existence of these two distinct varieties was founded on certain differences of behavior of oxygen, according as it was obtained from alkaline peroxides or from the peroxide of manganese or of lead ; that obtained from the alkalies having a reducing, that from the man- ganese and lead oxides an oxidizing action. But according to the experiments of Von Babo, Sir Benjamin Brodie, and others, it is probable that Schonbein's so-called antozone is the peroxide of hydrogen of Thenard. Prop- erties. Ozone is insoluble in water, alcohol, and ether, although M. Oarius asserts that 100 volumes of water will absorb about 0*5 volume of the gas. Its specific gravity is greater than that of oxygen in the proportion of 3 to 2. Air containing ozone has an irritating action upon the lungs when breathed, and when large quantities are present death may be produced. Experiments made by Dr. Kedfern of Queen's college, Belfast, show that the inhalation of oxygen containing only -%^ of its volume of ozone is rapidly fatal to all animals, while the gas freed from ozone is comparatively harm- less. Ozone causes death by producing intense congestion of the lungs, with emphysema and distention of the right side of the heart with blood. From experiments of Mr. Dewar and Dr. McKendrick it appears that atmos- phere highly charged with ozone diminishes the number of respirations per minute, less- ens the strength of the cardiac pulsations, and lowers the temperature from 5 to 8 F. The blood is found after death in a venous con- dition. Ozone is an exceedingly powerful oxidizing agent, corroding cork, paper, ani- mal membrane, caoutchouc, and other organic substances, and rapidly oxidizing iron, cop- per, mercury, and moist silver. M. Houzeau Comptes rendus, 1872) states that a consider- able quantity of it agitated with alcohol causes rapid oxidation, oxygenated water being at the same time produced; and he recommends its employment in a concentrated form as an oxi- dizing agent in organic chemistry. An ex- tended series of experiments have since been made by Prof. A. W. Wright of Yale college, to ascertain whether ozone could be advan- tageously used in the production of acetic acid from alcohol. It was obtained in a variety of ways from alcohol and ether, but not so rap- idly as might be expected from M. Houzeau's statement. (" American Journal of Arts and Sciences," March, 1874.) Ozone acts upon or- ganic substances in various ways. Vegetable colors are bleached or altered. Blue litmus is bleached without being first reddened, and the color of sulphate of indigo is discharged when the liquid is agitated with ozone. The processes of bleaching, either the old one of exposing the goods to moisture and sunlight, or the modern one of acting on them with chlorine, depends upon the production of ozonized air, or at least upon the production of nascent, active oxygen. Indeed, it is not improbable that when oxygen combines with a substance it passes into the molecular condition of ozone, either during the act of union or immediately preceding it. When the affinities are strong, as in the case of phos- phorus, an atmosphere of ozone may be pro- duced, surrounding the oxidizing body; but in the case of weaker attractions, no sensible evo- lution of ozone takes place. The most delicate test for ozone is to expose to its action a strip of paper moistened with a mixture of starch and iodide of potassium, by which the salt be- comes decomposed, and the liberated iodine unites with the starch, forming the charac- teristic blue compound, iodide of starch. It has been supposed that the fact that a paper prepared in this way and exposed to the at- mosphere often becomes blued, indicates the presence of ozone ; but this conclusion is not justified, because other agents, especially oxide of nitrogen, will also produce the same effect. Schonbein, having found that the air of the country frequently colored delicate ozone test paper, inferred that this body is a normal con- stituent of the atmosphere, varying in quantity in different localities and under different cir- cumstances ; and with its presence or absence he attempted to connect certain catarrhal dis- eases. Dr. Andrews has prosecuted an ex- tended series of experiments, which, among other conclusions, sustain Schonbein's opinions in regard to the frequent presence of ozone in the air, but not those in regard to its connec- tion with diseases. Ozone is easily decomposed, or reconverted into common oxygen. It is de- stroyed by the dust and exhalations of cities, and in general by all matter in a condition to become easily oxidized. It is found in the greatest proportion in the air of mountains, and at the seaside. An elaborate report made by Ebermeyer in 1873 on the physical influ- ence of forests, says that in open fields the air is richest in ozone, and in general in places of great atmospheric moisture. In a forest there is more ozone in the upper stratum of air in the branches of the trees than near the ground, owing to the fact that ozone is absorbed by the decaying matter on the ground. During a fog the quantity of ozone is small, and also during bright weather and northerly winds ; a change to southerly winds and rains increases the quantity, and the air is rich in ozone during thunder and snow storms. The assertion that an outbreak of cholera is accompanied with an absence of ozone seems not to be sustained, although such absence is regarded by Dr. An- drews as indicating that the air is adulterated.