536 - .\ 7- REPORT — 1903.' - ? 



The '^ rays' seem certainly to be atoms of resinous electricity — electrions, as I 

 have called them (to specialise Johnstone Stoney's ' electron,' which might be 

 either a vitreous or resinous atom of electricity, or an atom of matter deprived of 

 its natural quantum of electricity). The ' a rays,' accordinp^ to my proposed 

 atomic resuscitation of Aepinus's doctrine, are atoms or molecules of matter, 

 probably atoms of radium, or perhaps molecules of bromide of radium, either 

 deprived of electrions, or havin": less than their neutralising quantum. 



The electro-ethereal hypothesis, referred to in my communication of last 

 Thursday to Section A, afibrds a ready explanation of the relative penetrativities 

 of the three radiations, and of the fact that each one of them makes its existence 

 known to us by conferring electric conductivity on air or any ordinary gas in which 

 it is present. 



Taking the y rays first, we have to explain the free penetration of unelectrified 

 radium molecules through dense liquid or solid matter. An easy assumption suffices : 

 let the Boscovichian mutual forces (that is, the chemical affinities and the repul- 

 sions) between an atom of radium and the atoms of lead and other permeable 

 substances be absolutely zero, or small enough to allow the known permeation. 



Taking, next, the a radiation. The apparent great absorption of the vitreous 

 electric emanation from radium is only apparent ; it means that an atom shot 

 from radium with less than its neutralising quantum of electrions cannot go far 

 through a solid or liquid without acquiring the neutralising quantum. 



The ^ absorption may be regarded as probably real. Atoms of resinous 

 electricity shot from radium cannot be expected to enter a screen of metal, or 

 glass, or wood, or liquid, and leave at the other side, irrespectively of the insulation 

 of the screen and of the radium. The full consideration and experimental 

 investigation of the emission of atoms of resinous electricity from radium 

 hermetically sealed in a glass bulb or tube is forced upon us. It has, I believe, led 

 to surprising and interesting results. As to the y rays, there is no difficulty in 

 supposing that non-electrified vapour of radium passes very freely through glass 

 or metals without any electric disturbance. It has been published, on authority 

 so far as I know unquestioned, that loss of weight in the course of a few months 

 has been proved. Full information on all that is known on this subject will no 

 doubt be brought forward in the course of the discussion to be opened by 

 Professor Rutherford. I regret much that I am not able to be present, and I 

 shall look forward with eagerness to the earliest published reports of the 

 discussion. 



Returning to Becquerel's original discovery in respect to uranium and salts of 

 uranium, the electric conductivity induced in air and other gases by a radio- 

 active substance ; we have a ready explanation in my atomic resuscitation of the 

 old doctrine of Aepinus. The ordinary thermal motions within any solid, or 

 liquid, or gas, must cause occasional shootings out of the electrions from the 

 substance, and the motions of these electrions under the influence of electrostatic 

 force must contribute to the electric conductivity of the gas ; must, in fact, con- 

 stitute all of it which is not due to transport of atoms of the gas carrying less 

 than the neutralising quantum of electrions. Thus every substance, solid, liquid, 

 or gas, must possess radio-activity. It is exceedingly interesting to find in Strutt's 

 short paper ' On Radio-activity of Ordinary Materials,' ' that the electric conduc- 

 tivity of dry air contained in a cylinder of solid material differs largely for 

 different materials (1-3 for glass coated with phosphoric acid, 1*4 aluminium, 

 2 to y-3 various ordinary metals, 3-9 platinum) ; and to be told that radium is 

 300,000,000 times more active than the most active common material that he ex< 

 perimented with. How are we to explain this enormous radio-activity of radium ? 

 I venture to suggest that it may be because it is exceedingly poly-electriouic ; 

 that the saturating quantum of electrions in an atom of radium may be hundreds, 

 or thousands, or millions of times as many as those of atoms of ' ordinary material.' 



But this leaves the mystery of radium untouched : Curie's discovery that it 

 (perpetually ?) emits heat at a rate of about 90 Centigrade., Cfilqries per gramme 



' Phil. Mag. June 1903. 



