. Radioactive transformations . initial rise in the ThX curve is seen to correspond to a fall inthe recovery curve of the thorium, and when the activity ofThX has almost disappeared the activity of the thorium haspractically reached a maximum value. The sum of the activi-ties of the ThX and of the thorium from which it was separatedis very nearly constant over the whole range of the two curves of recovery and decay are complementary toeach other. As fast as the ThX loses its activity, the thoriumregains it. This relation between the curves is, at first view,most remarkable, and
. Radioactive transformations . initial rise in the ThX curve is seen to correspond to a fall inthe recovery curve of the thorium, and when the activity ofThX has almost disappeared the activity of the thorium haspractically reached a maximum value. The sum of the activi-ties of the ThX and of the thorium from which it was separatedis very nearly constant over the whole range of the two curves of recovery and decay are complementary toeach other. As fast as the ThX loses its activity, the thoriumregains it. This relation between the curves is, at first view,most remarkable, and it would appear as if there were somemutual influence between the ThX and the thorium compoundfrom which it was removed, so that the latter absorbed the 58 RADIOACTIVE TRANSFORMATIONS activity lost by the former. This position is, however, quiteuntenable, for the rise and recovery curves are independent, andare unaltered if the thorium and ThX are kept in sealed vesselsfar removed from each other. If the thorium hydroxide after. Fig. of activity of thorium X and recovery of activity of thorium deprived of ThX. recovering its activity is again dissolved and ammonia added,the amount of ThX separated is found to be the same as thatobtained from the first experiment. This process can be repeatedindefinitely, and equal quantities of ThX always be separated, RADIOACTIVE CHANGES IN THORIUM 59 provided that about a month elapses between each precipitationin order to allow the thorium to regain its lost activity. Thisshows that there is a fresh growth of ThX in the thorium aftereach precipitation. We shall now consider the explanation of the connectionbetween the decay and recovery curves. For the moment weshall disregard the initial irregularities shown by the two curves,which will be discussed later. If the recovery curve of Fig. 16 *& J*9- fl y J> P?t 20 / XA / ^oSL ^ &o / 3 I i i i 2 i 6 2 0 2 4- 2 3 Time in Days Fig. 17. Decay curve of thorium X and recovery curve of th
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Keywords: ., bookauthorrutherfo, bookcentury1900, bookdecade1900, bookyear1906
