CHEMICAL SCIENCE. 219 



by electricity. For the preparation of ozonized oxygen, he recommends 

 the electrolysis of a concentrated solution of sulphate of zinc containing 

 undissolved crystals. Liebig's Annual Report. 



From the above it will be seen that chemists are not yet fully agreed 

 concerning the nature or production of this singular substance, ozone. 

 To Schonbein and Williamson we are indebted for most of our know- 

 ledge concerning it. The latter has supposed it to be a compound of 

 oxygen and hydrogen, from the fact, that, when the ozone completely 

 freed from moisture was passed over ignited copper, water was produced. 

 De la Rive produced it by passing a current of electricity through pure 

 dry oxygen gas, contained in a receiver. It is also obtained in large 

 quantities by passing oxygen gas over moistened phosphorus and after- 

 wards drying it. Thus prepared, it is a powerful chemical agent, 

 possesses bleaching properties, oxidizes the metals with rapidity, and 

 destroys India-rubber. The hydrogen acids of sulphur are decomposed 

 by it, water being formed by uniting with the hydrogen of the acid, and 

 sulphur being set free. Prof. Horsford has observed that ozone sub- 

 jected to a heat of 130 Fahrenheit entirely loses its properties. Ozone, 

 like chlorine, precipitates iodine, coloring a solution of iodide of potas- 

 sium and starch a deep blue color. The peculiar smell prevalent in the 

 vicinity of objects struck by lightning, as well as that occasioned by the 

 excitation of an electrical machine, and by the striking of two pieces of 

 silica together, is believed to be occasioned by ozone. Editors. 



METHOD OF DETERMINING THE AMOUNT OF OZONE IN THE 



ATMOSPHERE. 



AT the meeting of the American Association, an instrument for 

 determining the relative quantity of ozone in the air was presented by 

 Prof. Horsford. It consisted of a tube, containing at one end a plug 

 of asbestos, moistened with a solution of iodide of potassium and 

 starch. This plug within the tube, attached to an aspirator, would, 

 as air passed over it, become blue. If much water flowed from the 

 aspirator, and of course much air flowed over the asbestos before it 

 became blue, the quantity of ozone indicated would be small. If but 

 little water flowed (and this could be measured), the quantity of 

 ozone indicated would be greater. The quantities of ozone would be 

 inversely as the volumes of air passing through the tube before blueness 

 is produced. 



THE MOISTURE AND AMMONIA OF THE ATMOSPHERE. 



AT the last meeting of the American Association, Prof. E. N. Horsford, 

 of the Lawrence Scientific School, communicated the results of some 

 observations undertaken witn the object of ascertaining the amount of 

 moisture, ammonia, and organic matter existing in the atmosphere. The 

 observations of the moisture recorded by Prof. Horsford commenced on 

 the last day of February, and were continued until the 12th of April, and 



