78 Trowbridge and Rollins — Radium and Electron Theory. 



the working of a great mind groping in a region not jet sub- 

 mitted to calculation. Lesser minds must, however, use caution 

 in publishing negative results ; for due regard must be had for 

 brevity of publication and the limits of experimentation. 



Can we not, however, imagine Faraday continuing his efforts 

 to discover some connection between the passage of light 

 through an electrolyte or a conductor and the passage of a cur- 

 rent of electricity, if he could penetrate such a conductor by 

 light. In other words, might he not have been tempted, if he 

 had had command of the X-rays or radium, to discover some 

 action of the energy emitted by the new and wonderful man- 

 ifestations on a current % Apart, however, from such a view of 

 the working of the great physicist's mind, can we not get a foot- 

 hold in mounting to the heights of the electron theory by 

 endeavoring to show that the X-rays or the emanations from 

 radium do or do not have a discoverable action upon the 

 passage of an electric current, through aluminium for instance ? 



It must be premised that no mass is ascribed to the electron. 

 Its supposable inertia is due to self-induction, and perhaps it 

 should not be called a body. On this conception it does not 

 seem probable that particles shot off from radium, or ions 

 resulting from the radiation of X-rays, could influence such 

 immaterial bodies. Nevertheless our view of the electron 

 theory might be influenced by proceeding to an actual test, 

 and by looking at the results and limitations of possible experi- 

 ments. We therefore experimented as follows : 



A meter of aluminium wire No. 24 was wound in five turns 

 around a thick sheet of lead which was eight centimeters in 

 length and one centimeter in width. The wire was wound 

 around the longest dimension of this shuttle-like piece of 

 metal, and was insulatepl from it by thin sheets of vulcanite. 

 The electric current, therefore, passed in one direction along 

 the upper layer of the wire, and in the opposite direction along 

 the lower layer. The lead, intervening between the upper and 

 lower layer, could serve to confine the radiations from suitably 

 placed radium either to the upper or the lower layer of wire. 

 The lead shuttle with its layer of wire was enclosed in a lead 

 cylinder and a specimen of pure radium bromide was enclosed 

 at one end of the layers of wire so that its emanations could 

 sweep along the upper or the lower layer of this wire. A 

 lead diaphragm could be used to shut off the entire effects of 

 the radium from the wires. 



The wire was made one branch of a Carey-Foster bridge ; a 

 suitable key made it possible to reverse the current through the 

 aluminium wire, and after adjustment the wire was exposed to 

 the radiations from the aluminium under the varying conditions 

 of reversals of current; radiations confined to the lower layer 



