INFLUENCED BY RADIUM. — CREIGHTOX. 41 



In cohimn six of this table the increases in Dressure due to 

 the deeoni])osition of the hydrogen peroxide are given, and on 

 comparing these resnlts with those given in Ta[)le I, it will be 

 seeoi that the effect of the radium is to produce a mucli greater 

 decomposition when lead nitrate is ])resent than when it is not. 



The Curies^ have shown that the effect of radium radiations 

 on oxygen is to transform it into ozOae. It is to this cause that 

 the decreases in pressure, corresponding to contractions in vol- 

 ume of the gas, observed in these experiments, have been 

 attriljuted. Why there is this periodic change, the accmnnla- 

 tive effect of which, as shown in Table II, is to enlarge the 

 volume of gas, will have to l>e investigated more thoroughly 

 before a suitable explanation can be given. On examining the 

 gas which was over the liquid when the experiment was over, it 

 was found that it contained 1.4 per cent. <tf ozone. 



The foregoing experiments show that neither solutions of 

 hydrogen peroxide (4.832 grams per litre), nor solutions of 

 hydrogen peroxide in which lead nitrate is present undergo any 

 decomposition in the dark; also that dilute solutions of hydro- 

 gen peroxide are slowly decomposed by radium, this decom- 

 position lx?ing much more rapid when the solution contains lead 

 nitrate and finely divided solid matter. Lastly, that ozone is 

 produced by the action of radium on the oxygen present. 



Action of Radium on Chloroform. 



It is well known that the reason chloroform, CIICI3, does 

 not give a precipitate with silver nitrate, is due to the fact that 

 it is unionized. As there seems to be no absolutelv undisso- 

 ciated substance, there is in chloroform, probably some few 

 chlorine ions; these are so few that when they unite with the 

 silver ions present ia the system, the amount of silver 

 chloride is very much too small to be visible. However, as soon 

 as these chlorine ions are removed from the system as undis- 

 sociated silver chloride, more of the chloroform dissociates in 



1 Loc. cit. 



