#8 ^^ro1^^SdlGBn5eln on Si£ ^ture^^Oz^L 



iS^^SLlio Quar.rio J5 oJ i\ snidnaee yd nerit .npiJieonniQaabj 

 r^. Qi>aTi titles qfpzone, Wy far toohiiBjHte W^.^cjmingl 



fey\ weight, still perceptibly colour the test-pas!|.^j,^^^ Y^oiTi 

 ^ Hence it follows that a quantity of aqueous vapour,' so small 

 J^S cannot be ascertained even by our most delicate hygrp- 

 scopicnl tests, is sufficiently large to produce with oxygen so 

 much ozone, that the presence of the latter is detected both 

 by the nose and the test-paste. MM. De la Rive's and Ma- 

 rignac's conclusion is founded upon the assumption that the 

 oxygen with which they made their experiments was abso- 

 lutely dry ; and if chemists admit that moist oxygen, after ha- 

 ving passed through strong sulphuric acid, does not contain 

 any trace of aqueous vapour, this inference is drawn from tlie 

 fact, that in oxygen treated in the manner indicated, no water 

 can be detected by any hygroscopical means hitherto known. 

 It is however very possible that minute quantities of vapour 

 escape the hygroscopic action, of sulphuric acid ; it is very 

 possible also that oxygen obtained even from melted chlo- 

 rate of potash still contaiuj^ some traces of water, and that 

 tbose minute quantities of vapour are large enough to pro- 

 duce ozone sufficient to colour the test-paste and aifect the 

 sense of smelling. Such a conjecture seems indeed to be far 

 less bold and more in accordance with the present state of 

 chemical science, than the view which MM. De la Hive and 

 Marignac have taken of the subject. If my opinion should 

 happen to be correct, the very property exhibited by oxygen, 

 of producing traces of ozone when the former happens to be 

 exposed to electrical action, would prove the most delicate 

 means of detecting the minutest quantities of vapour contained 

 l^^j^ that gas. . -'t 



..,.., In lorramg a judgement respectmg the nature oi ozone, 1 

 think one thing ought not to be left entirely out of consider- 

 ation, namely the fact, that in spite of some material diffdr- 

 ences of properties which exist between ozone and Thenard's 

 peroxide of hydrogen, both bodies exhibit many chemical 

 bearings very similar to each other. Both substances possess 

 bleaching powers, both of them transform a number of metallic 

 protoxides into peroxides, both produce sulphuric acid if added 

 to sulphurous acid, both are destroyed by a great number of 

 J, organic matters, &c. ; 



_fj-*,l myself and M. Marignac have ascertained that ozon^is 

 destroyed when exposed to a certain degree of temperature. 

 . Now that chemist must admit that heat has the power to an- 

 nihilate the peculiar condition which oxygen is said to assume 

 when placed under electrical influence. It app.(eju:s^tqme that 



