﻿Intelligence and Miscellaneous Articles, 79 



ON THE GENERATION OF OZONE IN OXYGEN AND IN AIR UNDER 

 THE INFLUENCE OF THE CONDENSED ELECTRICAL SPARK. BY 

 MM. L^HOTE AND ST.-EDME. 



Some time ago Mr. Ladd devised an electrical condenser which he 

 proposed as capable of producing large quantities of ozone by elec- 

 trifying oxygen. This apparatus consists of a wooden box 14 by 7 

 inches by 1 \ inch, inside which are six glass plates coated inside 

 with tinfoil, arranged so that the spark furnished by an induction coil 

 whose poles are connected with the two extreme plates sweeps by 

 condensation all the intermediate spaces. It is known that oxygen 

 which traverses Ladd's apparatus at the moment of discharge ac- 

 quires a powerful odour of ozone; hence the inventor ha? proposed the 

 use of the apparatus for injecting electrified oxygen into the ventilation 

 passages of large buildings — amphitheatres, hospitals, theatres, &c. 



The interest attaching to such a producer of ozone has increased 

 since General Morin called attention to the utility which the addition 

 of suitable quantities of ozone in ventilation might have as a de- 

 stroyer of miasmata, 



MM. Becquerel and Fremy have determined the proportion of 

 ozone which the electric spark produces when it strikes directly be- 

 tween two platinum wires fused in a glass tube full of pure oxygen. 

 It is also known that under these circumstances the air becomes 

 charged with nitrous products ; but we are quite ignorant of the 

 extent to which a spark from a powerful induction-coil, striking in 

 a cascade condenser like Ladd's apparatus, modifies the gas in con- 

 tact with its multifold surfaces. 



We began by arranging Ladd's apparatus so that it could rigo- 

 rously retain the pressure of the gas to be investigated, and then we 

 estimated the proportion of ozone formed in equal volumes of oxygen 

 and air circulating with the same velocities in the condensing- appa- 

 ratus, and under the influence of a spark of the same force (20 to 25 

 centims. in air). 



It has been established that the modified gas (oxygen or air) does 

 not attack tin. Solution of iodide of potassium is immediately 

 attacked in both cases ; silver is oxidized. It is difficult to ob- 

 serve any difference between the odours of oxygen and of air. 



The measurements were made in the following manner : — -The 

 gas emerging from the condenser passed through a Will's apparatus 

 containing a pipette of sulphuric acid in which was 0*061 grin, of 

 monohydrated acid, to which was added a cubic centimetre of solution 

 of neutral iodide of potassium containing 0" 1 gr. of iodide. The quan- 

 tity of ozone was determined alkalimetrically from the proportion of 

 potash formed. The following are the results obtained : — 



(1) The oxygen which passes into the condenser is pure and dry. 

 Six estimations gave for 10 litres of gas the proportions of ozone — 

 milligrammes. milligrammes. 



28-7 

 29-0 

 26-9 



26-3 

 16-8 

 15-9 



In other experiments the odorant gas was collected, on emerging 

 from the condenser, in a small gasometer containing distilled water. 



