378 'Boliwood — Ionium, a New Radio-active Element. 



0*76, a value which is in good agreement with the ratio of the 

 ranges of the a particles (qT7= 0*80 J emitted by the two sub- 

 stances. 



Life of Ionium. 



Some idea of the probable life of ionium, or, in other words, 

 of the time which would have to elapse before one-half of a 

 given quantity of this element would completely disintegrate 

 into other forms of matter, can be gained from the results of 

 experiments on the production of radium by ionium and on. 

 the growths of radium in pure uranium compounds. I have 

 found, for example, that the rate of production of radium in a 

 solution of ionium is constant, within the limits of experi- 

 mental error, for a period of over 500 days, although a change 

 of the rate by as little as iive per cent could probably have 

 been noted with certainty. This would indicate that the half- 

 value period, or time required for half of a given quantity of 

 ionium to be transformed into radium, is at least 25 years. I 

 have also found that the amount of radium formed in a solu- 

 tion containing 48 grams of purified uranium in a period of 

 over two and one-half years is probably less than 10 -11 gram, 

 and from this result it would appear that the life of ionium is 

 at least as long as that of radium, provided that no other 

 product having a slow rate of change occurs between uranium 

 X and ionium. If the life of ionium is of the same order of 

 magnitude as that of radium, then the amounts of the two sub- 

 stances contained in uranium minerals should be approximately 

 equal. If this is the case, then it ought to be possible ulti- 

 mately to obtain preparations of pure ionium, just as it has 

 been found possible to obtain pure radium salts. By a com- 

 parison of the activity of a known amount of pure ionium with 

 the activity of a definite quantity of pure uranium oxide it 

 would be a simple matter to determine the relative amounts of 

 these elements contained in a mineral. 



Ionium in Pitchblende Residues 



Through the kindness of Professor Rutherford and the 

 Royal Soeiety of London it has been possible for the writer 

 to examine a small quantity of material which had been sepa- 

 rated from the pitchblende residues presented to the Royal 

 Society by the Austrian Government. The material was 

 in the form of a crude hydroxide containing polonium, actin- 

 ium, radium, lead, zinc, and a large number of other elements, 

 and weighed, in the form of a wet paste, about 180 grams. It 

 w r as treated with hot dilute hydrochloric acid, the silica was 



