366 Boltioood — Ionium, a New Radio-active Element. 



(2) Action of hydrofluoric acid on the freshly precipitated 

 hydrates held in suspension in water. The portion dissolved is 

 only slightly active. By this method titanium may be sepa- 

 rated. 



(3) Precipitation of neutral nitrate solutions by hydrogen 

 peroxide. The precipitate carries down the active body. 



(4) Precipitation of insoluble sulphates. If barium sulphate, 

 for example, is precipitated in the solution containing the 

 active body, the active material is carried down by the barium. 

 The thorium and actinium are freed from barium by convert- 

 ing the sulphate into chloride and precipitating with ammonia. 



About two years later, in 1902, Giesel published an account* 

 of a highly radio-active substance which he had obtained from 

 pitchblende. He stated that this body was separated with the 

 cerium earths, and could be ultimately removed with the 

 lanthanum. A very characteristic emanation was evolved by 

 Giesel's more concentrated preparations and he at first used the 

 term "emanating substance" to distinguish the active material. 

 The emanating substance was not separated with the thorium, 

 and its chemical deportment was so different from that of the 

 latter element that in Giesel's opinion the " emanating sub- 

 stance" and Debierne's actinium could not be identical. In a 

 later paperf the name " emanium" was applied to the "ema- 

 nating substance." 



Giesel's claims for emanium were answered by Debierne in 

 a paper published in 1904,:j; stating that his " actinium" prep- 

 arations emitted an emanation similar to that noted by Giesel 

 from " emanium " and asserting that the active material con- 

 tained in them could not therefore be different. To this Giesel 

 replied by calling attention to differences, in the observed rates 

 of decay of the active deposits from "emanium" and "actin- 

 ium," and stating,§ moreover, that "Debierne no longer uses 

 the thorium of the pitchblende for obtaining the new prep- 

 arations, but uses instead, as I do, the cerium earths in which 

 the activity is concentrated, as Debierne acknowledges." Fur- 

 ther data on the chemical behavior of "emanium" were given 

 in a later paper by Giesel. || 



Certain experiments described by Marekwald^f were believed 

 by him to indicate that "actinium" and "emanium" were not 

 identical, but stood in a genetic relationship to one another. 

 A different and correct interpretation of Marckwald's results 



* Ber. d. chem. Ges., xxxv. 3608. 1902 ; ibid., xxxvi, 342, 1903. 

 f Ber. d. chem. Ges., xxxvii, 1696, 1904. 

 X Comptes r., cxxxix, 14, 588, 1904. 

 § Ber. d. chem. Ges., xxxvii, 3963, 1904. 

 | Ber. d. chem. Ges., xxxviii, 775, 1905. 

 IT Ber. d. chem. Ges., xxxviii, 2264, 1905. 



