Jagadish Chandra Bose

“ 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. ”

“ 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. ”