372 Boltwood — Ionium, a New IZadio-actvoe Element. 



nary paper* and other experiments were immediately begun 

 with the object of more carefully investigating the entire 

 matter. 



On learning of the outcome of my experiments. Professor 

 Rutherford then made some further tests of the preparation 

 of Giesel's " emanating substance " which lie had earlier 

 examined, and obtained positive evidence of the growth of 

 radium in this material. f This tended to strengthen rather 

 than otherwise the presumption that actinium was the inter- 

 mediate product between uranium and radium, although there 

 appeared to be certain theoretical objections to such a conclu- 

 sion.^: 



On continuing his experiments still further, Rutherford was 

 able to effect a partial separation of the emanating substance 

 proper from the radium-forming material by treatment of the 

 solution with ammonia and hydrogen sulphide. He therefore 

 concluded that ordinary commercial preparations of actinium 

 contained a new substance which was slowly transformed into 

 radium, was chemically quite distinct from actinium and 

 radium, and was capable of complete separation from them.§ 

 He was unable, however, to decide whether the new substance 

 emitted ionizing radiations or was rayless. He also obtained 

 results which indicated that the production of radium in solu- 

 tions of the parent was approximately constant for a period 

 of over 240 days from the time of its preparation.! 



In the continuation of my own experiments I prepared the 

 following materials : 



Solution 2. Another kilogram of the carnotite ore, similar 

 to that used in preparing the first solution, was similarly 

 treated with dilute hydrochloric acid and the insoluble material 

 was separated. This insoluble matter after drying in the air 

 had a weight of about 800 grams and consisted largely of 

 silica. The silica was completely removed by treatment with 

 hydrofluoric and sulphuric acids, and the residue of sulphates 

 remaining was almost entirely soluble in water. The solution 

 of the sulphates was treated with an excess of ammonia and 

 the precipitate of hydroxides was removed and carefully 

 washed with water. The hydroxides were dissolved in dilute 

 hydrochloric acid, the solution was treated with hydrogen sul- 

 phide and the precipitated sulphides were filtered off. To the 

 filtrate about one gram of thorium nitrate was first added and 

 then an excess of oxalic acid. The precipitated oxalates were 

 filtered off about two days later. A further quantity of about 



*Nature, Nov. 15, 1906: this Journal, xxii, 537. 1906. 



f Nature, lxxv. 270, 1907. 



i Rutherford, Radioactivity, p. 177. 



§ Nature, lxxvi, 126, 1907." 



|[ Phil. Mag., xiv, 733, 1907. 



