of the Radio-active Elements. 



79 



In the table which follows (Table I) are given the results 

 obtained from the calculation of the ratio of the percentage 

 of lead to that of uranium contained in the different minerals 

 as indicated by the analyses. 



No. Mineral Locality 



1. Uraninite, 

 Glastonbury, Conn., 



2. Uraninite, 

 Glastonbury, Conn., 



3. Uraninite, 

 Glastonbury, Conn., 



4. Uraninite, 

 Glastonbury, Conn., 



5. Uraninite, 

 Glastonbury, Conn., 



6. Uraninite, 

 Branchville, Conn., 



7. Uraninite, 

 Branchville, Conn., 



8. Uraninite, 

 Branchville, Conn., 



9. Uraninite, 

 Branchville, Conn., 



10. Uraninite, 

 .Spruce Pine, N. C, 



11. Uraninite, 

 Spruce Pine, N. C, 



12. Uraninite, 

 Spruce Pine, N. C, 



13. Uraninite, 

 Marietta, S. C, 



14. Uraninite, 

 Llano Co., Tex., 



15. Uraninite, 

 Llano Co., Tex., 



16. Mackintoshite, 

 Llano Co., Tex., 



17. Yttrocrasite, 

 Eurnet Co., Tex., 



18. Samarskite (?) 

 Douglas Co., Colo., 



19. Samarskite (?) 

 Douglas Co., Colo., 



20. Samarskite (?) 

 Douglas Co., Colo., 



21. Uraninite, 

 Annerod, Norway, 



Per 



cent 



TJ 



70 

 70 

 70 



72 

 72 

 74 

 75 

 74 

 66 

 77 

 77 

 67 

 71 

 55 

 56 



Per 



cent 

 Pb 



Ratio 

 Pb 

 U 



Analysis by 



•9 



0'( 



•o 



0'( 



•8 



o-( 



•o 



0-( 



•9 



0M 



•o 



o- 



•o 



o-< 



•o 



0M 



•5 



o-< 



•9 



o- 



L-2 



o- 



•3 



o- 



•3 



o- 



■4 



o- 



»-5 



o- 



041 Hillebrand, this Jour- 

 nal, xl, 384, 1890. 

 043 Hillebrand, I. c. 



040 Hillebrand, I. c. 



Hillebrand, I. c. 



040 Hillebrand, I. c. 



054 Hillebrand, I. c. 



053 Hillebrand, I. c. 



054 Hillebrand, I. c. 



053 From an analysis by the 



writer. 

 051 Hillebrand, I. c. 



055 Hillebrand, I. c. 



049 From an analysis by the 

 writer. 



046 Hillebrand, this Jour- 

 nal, xlii, 390, 1891. 



17 Hillebrand, I. c. 



19 3-4 0-18 



2-3 0-44 0-19 



3-5 0-67 0-19 



3-7 0-74 0-20 



5-1 0-99 0-19 



66 8'4 0-13 



Hidden and Mackintosh, 

 this Journal, xxxviii, 

 481, 1889. 



Hillebrand, this Jour- 

 nal, xlvi, 98, 1893. 



Hidden and Warren, this 

 Jour., xxii, 515, 1906. 



Hillebrand, Proc. Col. 

 Sc. Soc, iii, 38, 1888. 



Hillebrand, I. c. . 



Hillebrand, /. c. 



Hillebrand, this Jour- 

 nal, xl, 384, 1890. 



