Experiments on Positive Rays. 251 



forming aggregates, thus becoming, from this point of view, 

 much larger systems and having greatly increased capacity. 

 The same considerations would apply to a gas forming a 

 surface layer on a piece of melal or on a solid or liquid, and 

 may account for the electrification observed when gases 

 bubble through liquids. 



In the case of salts in flames when there is also ioniza- 

 tion, it is to be remarked that the ionization is not of the 

 type that would be produced if the metal in the salt were 

 positively electrified and the acid radicle negatively ; for in 

 this case the carriers of the negative electrification are cor- 

 puscles and not negatively electrified atoms. The charging 

 up of the positive ion in the flame may be analogous to the 

 emission of negative corpuscles from hot metals. 



L. Bloch (Annales de CJdmie et de Physique, xxii. pp. 370 

 ■& 441, xxiii. p. 28), who has made a very interesting series 

 of experiments on the connexion between chemical charge 

 and ionization, found that the flame of burning sulphur did 

 not conduct when its temperature was below 400° C, but 

 had great conductivity when the temperature was raised to 

 a much higher value. He further show r ed that in the many 

 cases of chemical action on which he made observation, 

 which included the dissociation of arseniuretted hydrogen, 

 the oxidation of nitrogen bioxide, the action of chlorine 

 on arsenic, the chemical action w T as not accompanied by 

 ionization. 



The Faraday cylinder method may be used to obtain 

 information as to how the various atoms in a complicated 

 molecule are linked together, 



A curve got by the use of the Faraday cylinder method when 

 the discharge passed through phosgene gas C0C1 2 , is shown 

 in fig. 26. The curve shows that the carriers of the positive 

 electricity were the atoms of C, 0, CI, the molecule of CO, 

 Cl 2 and CC1 and COCl 2 ; the negative carriers were C, 0, 

 CI. It will be noticed that only a small fraction of the 

 current is carried by free carbon and oxygen atoms, showing 

 that in phosgene the carbon and oxygen atoms are so firmly 

 united that the greater part of them remain combined even 

 when the gas is dissociated. Fig. 27 is the curve for C0 2 . 



Retrograde Rays. 



The existence of positively electrified particles moving 

 away from the cathode was observed by Villard (Comptes 

 Rendus, cix. p. 42) and the author. I have recently 

 succeeded in obtaining a photograph of these rays. The 

 method employed was to use the perforated electrode which 



