394 Scientific Intelligence. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. On the Production of Ozone from pure Oxygen. — Having 

 had occasion to prepare oxygen gas of a high degree of purity 

 and to transfer it to experimental apparatus of various kinds 

 "without contamination, Shenstone and Cundall have taken the 

 opportunity to study the conditions of the preparation of 

 ozone from pure oxygen under the influence of the silent elec- 

 tric discharge. For the production and storage of the oxygen, 

 the authoi's contrived a special, form of apparatus made entirely 

 of glass, the various parts of which are united by fusion. It 

 consists essentially of a flask for generating the oxygen, con- 

 taining a previously fused mixture of potassium and sodium 

 chlorates in molecular proportions, and a cylinder of about a liter 

 capacity, for storing it. To the right of this reservoir and to the 

 left of the flask, connections are made with Sprengel pumps, 

 glass taps of special construction being placed between. A third 

 tap closes the tube between the flask and reservoir. At its 

 lower end the storage cylinder is connected with a mercury res- 

 ervoir, and sampling tubes are provided by which specimens of 

 the gas may be obtained for examination. The precautions re- 

 quired in filling the reservoir are detailed in the paper. It was 

 found that the most satisfactory reagent for determining the 

 purity of the oxygen was phosphorus, and it was found possible 

 by means of a special pipette, to avoid the introduction of any 

 inpurity. So that after the absorption, not more than 1/5000 of 

 residual gas remained. The authors believe however, that the 

 purity of the oxygen actually exceeds this value. For the ozone 

 experiments, the oxygen was collected in a glass cylinder, into 

 the top of which the neck of a cylindrical bulb was fastened, the 

 bulb projecting into the cylinder, leaving an annular space be- 

 tween the walls of the two. At its lower end the cylinder termi- 

 nated in a smaller S-shaped tube upon which was a globe con- 

 taining phosphoric oxide. Nine months after filling the apparatus 

 with oxygen, the outer end of the S-shaped tube was broken off 

 under sulphuric acid, the level of the liquid noted, and the en- 

 closed gas electrified by connecting sulphuric acid placed in the 

 cylindrical bulb, and a strip of tin foil opposite it on the outside 

 of the glass cylinder, with the terminals of an induction coil 

 capable of giving a four or five inch spark. A steady diminution 

 in the volume of the gas set in, indicated by the rise of the acid 

 in the S-shaped tube, until in the first experiment lasting 24 

 hours the contraction indicated that a conversion into ozone had 

 taken place, of about 7*5 per cent of the oxygen employed. In 

 a second experiment the gas was electrified at intervals for three 

 days and the contraction indicated a conversion of 15 per cent of 

 the oxygen into ozone. Doubting the accuracy of estimating the 



