...these are almost certainly to be accounted for in another way. It will be shown later (section IX.) that about 21 per cent, of the normal radioactivity...independent of the molecular conditions is not final. Tin- following experiment, however, makes it extremely probable. A quantity of thorium nitrate as obtained...

...material. This portion is of' course a variable; and since it is divided among the total mmmmmount of matter present, the conditions of aggregation,...will affect the value of' this part. This effect of excite(l radioactivity in thoi'iummt mmmmmkes a certain answer to the qumestion difficult, and on this...