were actually measured with a stop watch as recorded, but since there could be no possibility of mistaking the 100-second speed, it was observed only four or five times. It will be seen from [Table XII] that out of 44 catches of ions produced by very hard X-rays there is not a single double. As a result of observing from 500 to 1,000 catches in the manner illustrated in [Table XII], we came to the conclusion that, although we had entered upon the investigation with the expectation of proving the existence of valency in gaseous ionization, we had instead obtained direct, unmistakable evidence that the act of ionization of air molecules by both primary and secondary X-rays of widely varying degrees of hardness, as well as by
- and
-rays, uniformly consists, under all the conditions which we were able to investigate, in the detachment from a neutral molecule of one single elementary electrical charge.
III. RECENT EVIDENCE AS TO NATURE OF IONIZATION PRODUCED BY ETHER WAVES
Although Townsend and Franck and Westphal dissented from the foregoing conclusion, all the evidence which has appeared since has tended to confirm it. Thus Salles,[60] using a new method due to Langevin of measuring directly the ratio
of the mobility to the diffusion coefficient, concluded that when the ionization is produced by