310 Royal Society .— 



"When the electrized gas was passed through a solution of hy- 

 posulphite of soda, it was found to undergo a diminution in volume 

 equal in amount to twice the " iodine-titre " of the gas, the mean of 

 twelve experiments giving for this value 1*9, the "titre" being 1. 

 The oxidation also effected in the solution of hyposulphite of soda 

 was equal to three times the "titre" of the gas, the mean of a set of 

 five experiments giving for this value, according to one method of 

 estimation, 2*72, and according to a second and more exact method 

 3*01 . Again, the oxidation effected by the electrized gas in a so- 

 lution of protochloride of tin was equal to three times the " titre " 

 of the gas, the value found as the mean of six experiments being 

 2*77. In two experiments also, in which both the oxidation and 

 contraction were respectively estimated, 2*75 and 2-69 were the 

 values found for the oxidation, and 1*9 and 1*8 the values found 

 for the contraction, the " titre " of the gas being in all cases assumed 

 as 1. These experiments conclusively demonstrate the identity of 

 the ozone formed by the action of electricity upon carbonic-acid gas 

 with the ozone similarly generated from pure oxygen. 



Various experiments were instituted with the view of ascertain- 

 ing the conditions most favourable to the conversion of a large 

 proportion of this oxygen into ozone. The conclusion at which I 

 arrived was that the greatest proportion of ozone in relation to 

 the total oxygen was produced when a rapid current of dry car- 

 bonic-acid gas was acted upon at a low temperature by electricity 

 of feeble tension. When these conditions were realized, it was 

 found that 75 per cent, of the total oxygen eliminated in the in- 

 duction-tube by the decomposition of the carbonic-acid gas could 

 readily be converted into ozone, but that it was difficult to pass 

 this limit. This amount corresponds with the formation of a gas 

 constituted of ozone and oxygen in the proportion of two units of 

 ozone to one unit of oxygen, the matter of the oxygen being thus 

 distributed 2£ 3 -f- £ 2 . In several experiments, nevertheless, this limit 

 was considerably exceeded ; and a table is given of nine experiments, 

 in which the amount per cent, of ozone ranged from a minimum of 

 76*6 per cent, to a maximum of 85*5 per cent. This latter amount 

 corresponds with a gas constituted of ozone and oxygen in the pro- 

 portion of four units of ozone to one of oxygen, thus 4£ 3 + £ 2 . In 

 this case the ratio of the total oxygen present to the titre of the 

 gas is 3*5 ; if the whole oxygen were converted into ozone, the value 

 of this ratio would be 3. 



These experiments, taken in connexion with those described in 

 my previous communication, leave no room for reasonable doubt 

 as to the composition of the unit of ozone, which is the triad form 

 of the element oxygen, and is to be symbolized as £ 3 , an hypothesis 

 henceforth to be regarded as conclusively demonstrated. This re- 

 markable discovery has many important bearings upon chemical 

 theory, especially in relation to the problem elsewhere raised by me 

 of the true nature of the elemental bodies and the constitution of 

 the unit of the element chlorine, which ozone so closely resembles 

 in its chemical properties, and which is also a triad element sym- 

 bolized as a\ 2 . 



