RECENT ELECTRICAL DISCOVERIES 123 



"it is a molecular mode of motion," is an absurd- 

 ity, for motion is an effect produced by a cause, 

 and all motion is caused by electric energy. And 

 the mode of motion is simply the manner in which 

 the law of electro-magnetism operates. Thus there 

 may be an electric law yet undiscovered by which 

 a substance like radium may draw electric energy 

 from the air and keep its force and bulk unim- 

 paired for many months, or perpetually. 



But radium raises many other questions affect- 

 ing the nature of light and heat, such as how such 

 great heat and light can be condensed into so small 

 a compass and evolved with such wonderful power. 



Prospecting for valuable metals by electricity 

 has been recently introduced in Wales with remark- 

 able success. In the Cwncystwyth mines in Corn- 

 wall new and valuable deposits of ore and blende 

 were located. These mines have been worked for 

 over fifteen hundred years, and much of this time 

 the search for additional lodes has been going on; 

 yet this electrical device accomplished in a few hours 

 what fifteen centuries of search failed to discover. 



By the electric method of prospecting a current 

 of high potential 30, 000 volts or more is employed 

 to energize a piece of ground supposed to contain 

 mineral. The current is taken from the terminals 

 of the generating coil to metal rods or electrodes 

 which are pushed an inch or two into the earth. 

 From these distributers the lines of force spread 

 out in both vertical and horizontal planes and 

 may be made to extend over an area of several 

 miles. 



Their presence is detected by means of a delicate 

 telephonic receiver connected with a second pair of 



