PART II. POLAR MAGNETIC PHENOMENA AND TERRELLA EXPERIMENTS. CHAP. VI. 



713 



When the box was opened, the passing of the finger over the patch of grease produced an abun- 

 lance of tiny drops of quicksilver. We thus see that the quicksilver corpuscles from the greatly disinte- 

 .rating cathode-globe in this large vacuum-box (1000 litres) are thrown against the glass walls, as a rule 

 nth the result that they are reflected back again. It wax only where the surface of tin- glass was greasy 

 hnt the corpuscles adhered. 



This result made me think of all my former vain attemtps to make the corpuscles thrown off from 

 palladium cathode produce a shadow upon the glass wall of the vacuum-tube, of an object standing 

 tween the cathode and Ihe wall. It seems natural to suppose that corpuscles that are disintegrated 



Fig. 265 b. 



om a cathode have not generally sufficient velocity to adhere when they strike a wall, but that at first 

 icy generally rebound, only a few of them adhering immediately. When a coating is once formed, the 

 .her corpuscles have a better opportunity of adhering, possibly on account of electric attraction. 



In order to test the correctness of this assumption, a former experiment was repeated, in which 

 :> shadow-formation had been obtained. On this occasion all interior surfaces were greased with vase- 

 ic-oil, whereas before they had been dry and clean. The result, as the accompanying reproduction of 

 photograph (fig. 266) shows, was in astonishing conformity with the assumption. 



The vaseline-oil employed soon stiffens, it is true, under the influence of the cathode-rays, but the 

 tty substance formed "catches" the corpuscles and prevents them from being reflected back from the 

 alls. It is thus possible in this way to demonstrate the course of the "metal rays" from the cathode, 

 ithout having complications introduced into the phenomena by reflected rays. 



Exceedingly peculiar conditions would arise in a vessel filled with flying corpuscles, if a patch on one 

 " its walls had the property of intercepting all particles that had the greatest kinetic energy, while those 

 ith small velocity rebounded. It is assumed that the walls of the vessel, apart from the patch, throw 

 ick all corpuscles. Might we perhaps replace the famous little Maxwell's demon with a patch of grease? 



