IV 



reach the earth. The existence of such pencils of rays was clearly presupposed to be necessary 

 to the theory as already formulated by me in 1899; and this assumption is now said to be 

 untenable. 



From the results which are here produced, however, it will undoubtedly appear that there 

 must be a flaw somewhere or other in the reasoning of the distinguished natural philosopher; 

 for one is inclined to regard the descent of the above-mentioned pencils of rays to the earth as 

 an experimental fact. 



I have also endeavoured, in Chapter VI, directly to demonstrate the points in which Schuster's 

 assumptions in no way admit of being applied to our case. I will here, moreover, with regard 

 to the electrostatic repulsion between our helio-cathode rays, refer to formulae by OLIVER HEAVISIDE. 

 In his Electrical Papers, Vol. II, Part III, p. 495, mathematical investigations are to be found of 

 electrically charged corpuscles in translatory motion, and from these it appears, on a discussion 

 of the formulae, that when the velocity of the corpuscles equals that of light, the electrostatic 

 repulsion between the rays maintains the balance with the electro-dynamic attraction. And as 

 regards our helio-cathode rays, their velocity, according to the theory, differs no more than a 

 hundred metres from that of light. 



We find, with regard to these rays that the acceleration with which an electron is repelled 

 from the pencil of rays will not be what Schuster gives, but from the very first moment 3.3 million 

 times less. Subsequently this acceleration decreases with very great rapidity, in so far as the 

 longitudinal mass of the repulsed electron comes into play. 



In a paper he has just published, HALE communicates some preliminary results on the 

 general magnetism of the sun, at which he has arrived by the aid of instruments and experi- 

 mental methods that are altogether admirable. He considers that the entire sun must be mag- 

 netic, with polarity like that of the earth, and with a vertical intensity at the poles of about 

 50 gausses. 



These results seem at first sight to be quite irreconcilable with those in this work. If the 

 sun were perceptibly magnetic in the same manner as the earth, but with an intensity 70 times 

 as great, it is perfectly certain that no helio-cathode ray of the kind in question could ever reach 

 the earth. 



Hale, however, is of opinion that the magnetism of the sun differs radically from that of 

 the earth. 



It seems to me that the phenomena observed by Hale might be explained as the effects 

 produced by invisible spots, or by the pores, considered as electric vortices, notwithstanding 

 all the reasons that Hale adduces against such an assumption. 



In a note to the Comptes Rendus de 1'Academie des Sciences, Paris, Aug. 25, 1913, I have 

 given the reasons that favour my view. 



The experimental investigations which at first were designed to procure analogies capable 

 of explaining phenomena on the earth, such as aurora and magnetic disturbances, were subse- 

 quently extended, as was only natural, with the object of procuring information as to the con- 

 ditions under which the emission of the assumed helio-cathode rays from the sun might be 

 supposed to take place. 



The magnetic globe was then made the cathode in the vacuum-box, and experiments were 

 carried on under these conditions for many years. 



It was in this way that there gradually appeared experimental analogies to various cosmic 

 phenomena, such as zodiacal light, Saturn's rings, sun-spots and spiral nebulae. 



