448 Intelligence and Miscellaneous Articles. 



presence of an excess of oxygen. For example, on mixing, over 

 mercury, equal volumes of oxide of carbon and oxygen, I found 

 after some hours 93 per cent, of the oxide of carbon changed into 

 carbonic acid, 5 per cent, into suboxide, and 2 per cent, unaltered. 

 There remained 42 per cent, of free oxygen, including a little ozone. 

 The presence of an excess of oxygen, therefore, does not determine 

 the total combination of the oxide of carbon. 



Reciprocally, it does not prevent incipient decomposition of 

 carbonic acid, as I have specially ascertained. Nay, more : in a 

 mixture of equal volumes of carbonic acid and oxygen I found, 

 after twelve hours, in a system of two concentric tubes, 5 per cent 

 of the gas decomposed into carbonic oxide and oxygen. This oxy- 

 gen contained a strong dose of ozone (or of percarbonic acid). 



These results establish the existence of the two opposite reactions 

 provoked by the effluvium, and consequently that of the chemical 

 equilibria determined thereby ; but it has not been possible to extend 

 them on both sides to the same limit, on account of the secondary 

 reactions, such as the formation of the suboxide of carbon and the 

 absorption of oxygen by mercury. 



4. The decomposition of carbonic acid by the effluvium, effected 

 in a space free from mercury and oxidable substances, gives rise to 

 special phenomena worthy of our interest ; for they lead one to 

 suspect the existence of percarbonic acid. In fact, in an experi- 

 ment, after twelve hours of the effluvium acting upon a gas enclosed 

 in the annular space of the concentric tubes hermetically sealed 

 which I am accustomed to emplo} r , I found 16 hundredth parts of 

 of carbonic acid decomposed. The gas which was formed attacked 

 mercury and oxidable bodies with extreme violence. 



If the oxidating portion of this gas were regarded as ozone, the 

 quantity of that substance would amount to 30 per cent, of the 

 oxygen liberated in one experiment, and up to 41 per cent, in an- 

 other — enormous proportions, and much higher than those produced 

 with pure oxygen*. 



It would be very interesting to isolate the oxidating material 

 formed in this reaction; but when one essays to eliminate the 

 carbonic acid and the oxide of carbon contained in the preceding 

 mixture, the oxidating gas is destroyed by the reagents employed, 

 which does not permit its isolation. This gas might be equally 

 regarded either as oxygen very rich in ozone, or as containing a 

 strong dose of percarbonic acid, C 2 O e ; but I have not succeeded 

 iu discovering any proper character to distinguish the latter com- 

 pound from ozone mixed with carbonic acid. — Annates de Chimie 

 et de Physique, May 1879, ser. 5, t. xvii. pp. 142-144. 



* These proportions are relative to the oxygen produced by the decom- 

 position of carbonic acid — which oxygen formed only 8 hundredths of the 

 volume of the whole mixture in one experiment, 5 hundredths in the 

 other. 



