Plan of Atom capable of Storing an Electrion. 695 



The most convincing results were obtained with tube 9, 

 mounted with non-adherent armatures. 



The separate readings are here given o£ a number of 

 observations. With a 10-millimetre spark the elongation 

 for a charging of about one minute is approximately 

 4*5 X 10 -4 mm., and this is reduced to one-third of its value 

 when the tube is charged four times as quickly. This same 

 effect of the time is noticeable throughout the table. 

 Evidently very little of the effect would remain if the charging 

 were made instantaneously. The times of charging are only 

 given approximately, and this accounts for the variations in 

 the readings when the potentials and the times are the same. 

 There is no evidence of the law that the deflexions are 

 proportional to Y 2 /d 2 . 



In concluding this work on electro striction, which has 

 extended over years, I have some hope that the results given 

 will be sufficiently convincing to prove that the effects which 

 have been observed by myself and others can be fully 

 accounted for by extraneous effects, and that when these are 

 eliminated the distortion of dielectrics by an electrical charge 

 also vanishes. 



University of Cincinnati, 



LXXYI. Plan of an Atom to be capable of Storing an Electrion 

 icith Enormous Energy for Radio-activity. By Lord 

 Kelvin *. 



§ 1. TIST a communication to the Philosophical Magazine of 

 JL October 1904, 1 described combinations of atoms and 

 electrions having certain definite qualities of radio-activity ; 

 holding myself, for the time, bound to the precise description 

 of the electric property of an atom of ponderable matter, 

 which 1 had suggested in § 4 of " Aepinus Atomised " 

 (Baltimore Lectures, Appendix E). In that description 

 each atom of ponderable matter is supposed to have ideal 

 electric matter of the vitreous kind distributed uniformly 

 through it. No longer binding myself by this limitation to 

 uniformity of vitreous electric density, I now propose to con- 

 sider an atom of ponderable matter intrinsically charged with 

 concentric strata of electricity, vitreous and resinous, of equal 

 electric density at equal distances from the centre ; and with 

 an excess of the total quantity of the vitreous above the total 

 quantity of the resinous. I still suppose (with, I believe, all 

 at present concerned with radio-activity) that free resinous 

 * Communicated bv the Author. 



