ELISHA MITCHELL SCIENTIFIC JOURNAL 59 



Debierne assumed it to be a new element and gave it the name 

 "Actinium". 



Now the question was raised, whether the radioactivity of 

 the Thorium compounds was caused by admixture of a little 

 quantity of Actinium, and whether Thorium obtained by any 

 means whatever is in every case radioactive. 



Rutherford tried to answer the question, whence the activity 

 of the Thoria came. He, by precipitation of Tlioria with 

 ammonia, obtained a filtrate which was much more radio- 

 active than the precipitate. He said that the activity of 

 Thorium is due to the body contained in the liquid and 

 called it Th X. Subsequent investigations from this savant 

 indicate the continued regeneration of Th X. In the labora- 

 tory of the University of North Carolina we have experiments 

 planned which promise an explanation of this, so we maj 

 defer further consideration for the present. 



Professor Hofmann, in Munich, and I, attacked the problem 

 and the results of our investigations are briefly presented 

 here. Incidentally it must be noticed that the Thorium, of 

 which I am talking-, means the old Thorium, the elementary 

 nature of which is now getting- very precarious by the splen- 

 did investigations of Dr. Baskerville which are astonishing 

 all the world. 



To decide the questions- mentioned above it was at first 

 necessary to study the minerals, from which the Thorium 

 preparations to be examined were obtained. All the preceding 

 investigations were made with commercial Thorium com- 

 pounds which came from monazite sand, exclusively I think. 

 We examined the Thorium obtained from the following min- 

 erals: broggerite, cleveite, euxeuite, samarskite, fergusonite, 

 xenotine, thorite, orangite, aschynite, monazite sand, gado- 

 linite, orthite and yttrotitanite. The Thoria was extracted 

 from these minerals by different methods according to their 

 composition. It was always separated from the other rare 

 earths by dissolving its oxalate in a hot solution of ammonium 

 oxalate and precipitating the Thoria in the cooled and diluted 

 filtrate by hydrochloric acid. 



