CHEMISTRY. 



287 





such as blood, &c., are brought about by means of substances which possess 

 the power both of exciting and carrying oxygen. 



Conditions Influencing the Production of Ozone ~by Electrolysis. !M. Hozeau 

 communicates the following as the result of recent investigations on this 

 subject: 



1. The composition and temperature of the liquid being constant, the 

 amount of ozone produced increases with the intensity of the pile, but not 

 proportionately. Thus eight of Bunsen's elements produced 0-00195 grm., 

 and eighty elements 0-00429 grm., in equal volumes of gas. 



2. The intensity of the pile and the composition of the liquid being nearly 

 constant, the amount of ozone produced decreases as the temperature 

 increases. 



3. The temperature of the liquid and the intensity of the pile being nearly 

 constant, the amount of ozone produced increases with the amount of sul- 

 phuric acid, but does not seem to be proportionate to it. 



It follows that in order to obtain the largest possible quantity of ozone by 

 means of a given intensity, it is necessary to employ water with a very large 

 proportion of acid. With eight of Bunsen's elements ozone is not generated 

 from water containing ^- its volume of acid, even after the addition of a 

 little chromic acid ; while it is produced by two elements from water mixed 

 with five times its volume of acid. The amount of ozone in oxygen, pro- 

 duced under various conditions, was found to vary from 0'002 to 0*007 grm. 

 in the litre. 



Professor Yan der 'Willigen states that he has observed the production of 

 ozone, when a thin platinum wire, about two inches thick, is fixed between the 

 arms of a Henley's discharger, which is included in the circuit of a Grove's 

 battery of six cells. The wire soon becomes white hot, and the odor of 

 ozone may be recognised along the whole length, but most distinctly at the 

 positive end. at that pole where oxygen would be eliminated in the voltameter. 

 (Compt. Eend. xliii. 34.) 



Observations and Experiments upon the Employment of Iodide of Potassium 

 as a Reagent for Ozone. A recent number of the Comptes Eendus contains 

 the following paper on this subject by S. Cloez : 



The experiments of Marignac, Fremy, and Becquerel, have done most to 

 clear up the question of the nature of ozone ; they prove completely the pos- 

 sibility of imparting to chemically pure oxygen all the properties of this 

 mysterious substance. 



Iodide of potassium being one of those substances upon which ozone is 

 capable of acting, paper soaked in a solution of starch containing 0'002 of its 

 weight of this iodide, has been prepared under the name of the ozonometric 

 reagent, not only to indicate the presence of ozone, but also to measure the 

 quantity contained in the air. If the coloration of this paper could only be 

 produced by ozonized oxygen, its employment would leave nothing to be 

 desired. But this is not the case ; acid vapors act upon iodide of potassium 

 in the same manner as active oxygen ; the essential oils exhaled by plants 

 have the same action, and prove that moist air, under the influence of the 

 direct light of the sun, colors the reagent, although we cannot suppose the 



