20] 



remained insoluble. This was washed repeatedly by decan- 

 tation, dried, and weighed. Its weight was '007 gramme. I 

 determined its activity to be a little over twenty times that 

 of uranium nitrate, but the measurement was necessarily only 

 approximate. The sample was forwarded to Professor Bragg 

 in March last, and he made its activity to be about nine 

 times that of UgOs, so the tw^o measurements agreed fairly 

 w^ell. The activity of this sample gradually increased to 12. 



I would like to take this opportunity of expressing my 

 thanks to Professor Bragg for the interest he has taken in 

 this research throughout, and for the time and trouble he 

 has expended in making measurements on active products. 

 On receipt of Professor Bragg's confirmation of the result 

 that a radio-active element of higher activity than either 

 thorium or uranium was present, more attention was given 

 to the chemical composition of the ore. Mr. G. J. Rogers, 

 A.R.C.S., the work's chemist, found uranium in both Treuer's 

 and Taylor's Shafts material to the extent of several per 

 cent., his highest result being 4'74 per cent. U..0-. I under- 

 stand that Dr. Cooke has also detected uranium in a sample 

 of ore in his possession. Mr. Rogers also found that the 

 Treuer's ore contained a little carbon, and made an approxi- 

 mate quantitive determination of its amount in a typical 

 specimen from Taylor's Shaft. Subjoined are his results 

 on material from both shafts : — 



(The carbon includes some volatile hydro-carbon.) 



All active specimens so far examined have been found 

 to contain a little lead, but the amount is very small, much 

 less than 1 per cent. A uranium determination was made 

 on a very interesting specimen from Treuer's Shaft. It is 

 apparently ordinary copper pyrites on quartz, and on one 

 side there is a mustard-yellow incrustation which closely re- 

 sembles carnotite. A piece of the pyrites was broken off, and 

 gave on analysis 1"91 of I^A- The preliminary w^ork on 

 the concentration of the activity having given satisfactory re- 

 sults, a kilogramme of ore from Treuer's Shaft (activity' '06) 

 was w^orked up, the original scheme of treatment being onlv 



