Page:On the Periodicity in the Electric Touch of Chemical Elements. Preliminary Notice.djvu/2

Rh used the term "Electric Touch," in the restricted sense of sensitiveness to electric radiation, the touch being regarded positive when there is a diminution of resistance by the action of radiation, and negative when radiation produces an increase of resistance.

In continuation of my previous investigation, I have completed a systematic inquiry into the action of nearly all the elements, including the metalloids and non-metals; also of alloys, amalgams, and compounds. Very great difficulty was at first encountered in working with the non-metals, which are extremely bad conductors. The difficulty 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 exhibiting this effect.

In the exhibition of the phenomenon of contact sensitiveness, various causes give rise to actions which appear at first to be very anomalous. These causes have been isolated and their effects separately studied. Results have thus been obtained which are uniformly consistent.

Experiments have specially been carried out in the following subjects:—


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


 * (2) The effects of various physical causes on the contact sensitiveness.


 * (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 the electric reversal.


 * The study of the above supports the following hypotheses:—


 * (a) That the contact sensitiveness depends on the chemical substance.


 * (b) 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 substance less negative. The change may in certain cases produce actual reversal.


 * (d) That the so-called "fatigue" is due to the presence of "radiation products."

A detailed account of these investigations will be communicated at an early date.