the Ehctrio Touch of Chemical Elements. 



451 



fore used the term " Electric Touch" in the restricted sense of sensi- 

 tiveness to electric radiation, the touch being regarded positive when 

 there is a diminution of resistance by the action of radiation, and 

 iiecjative when radiation produces an increase of resistance. 



In continuation of my previous investigation, I have completed a 

 systematic inquir}' into the action of nearly all the elements, including 

 the metalloids and non-metals ; also of alloys, amalgams, and com- 

 pounds. Ver}^ great difficulty was at first encountered in working 

 with the non-metals, which are extremely bad conductors. The diffi- 

 culty has, however, been overcome by the successful working of a new 

 method of radiation balance. As a result of these investigations, it is 

 found that the increase of resistance exhibited by elements is far from 

 being a rare phenomenon, nearly half the number of elements exhibit- 

 ing this effect. 



In the exhibition of the phenomenon of contact sensitiveness, various 

 ■causes give rise to actions which appear at first to be veiy anomalous. 

 These causes have been isolated and their effects separately studied. 

 Kesults have thus been obtained which are uniformly consistent. 



Experiments have specially been carried out in the following sub- 

 jects : — 



(1) On the passage of electricity through imperfect contacts. 



(2) The effects of various physical causes on the contact sensitive- 

 ness. 



(3) On the difference between mass action and molecular action. 



(4) On the changes produced in the sensitive substance by the action 

 of radiation. 



(5) On the cause of " fatigue." 



(6) On electric reversal. 



The study of the above supports the following hypotheses : — 



{(i) That the contact sensitiveness depends on the chemical sub- 

 stance. 



{h) That the sensitiveness of an element is a periodic function of its 

 atomic weight. 



(c) That the effect of radiation is to produce a molecular change or 

 allotropic modification of the substance acted on, so that a 

 positive substance becomes less positive, and a negative sub- 

 stance less negative. The change may in certain cases produce 

 actual reversal. 



((/) That the so-called " fatigue " is due to the presence of " radiation 

 products." 



A detailed account of these investigations will be communicated at 

 ^n early date. 



2x2 



