OBSERVATIONS ON RADIO-ACTIVITY. 



Total Activity as determined by Ionisation Produced in Air-gap. 



Mineral. 



Activity. 



Locality etc. 



Black oxide of Uranium, U 2 5 



100 



Taken as standard. 



Torbernite 



highly active 



Carcoar, N.S.W. (insufficient 

 for comparative test) 



Euxenite 



highly active 



Marble Bar Tinfields, W.A. 

 (insufficient corap. test) 



Gadolinite 



•88 



Cooglegong River — Green- 

 bushes Tinfield, W.A. 



Monazite 



11-30 



Pilbarra, W.A. 



Fine river sand with gold, 







tinstone, etc. 



8-49 



Tumberumba, N.S.W. 



Zircon sand with monazite ... 



•60 



Tooloon River, N.S.W. Con- 

 tains -45% thoria. 



Concentrated beach sand 



7-39 



Broken Head, Richmond 

 River, N.S.W. 



Ditto, ditto 



1-82 



Ballina, Richmond River, 



N.S.W. 



Concentrated river sand 



8-00 



Tasmania. 



Monazite 



5-47 



Torrington, N.S.W. A large 

 well developed crystal used. 



Ditto 



3-25 



Torrington, N.S.W. 



Ditto 



4-92 



Cow Flat,Torrington,N.S.W 

 contains -3% thoria. 



Ditto 



3-11 



20 miles W. of Torrington, 



contains 1'5% thoria 



Ditto 



4-46 



Ditto, contains 1-8% thoria. 



Ditto 



3-31 



"1 



Ditto 



300 



1 



Ditto 



3-41 



^Various samples from the 



Ditto 



3-13 



Gulf Mine.Emmaville. 



Ditto 



2-50 



J Contains - 6% thoria. 



Ditto 



4-50 



Paradise Creek, Emmaville, 



Foreign Minerals. 





N.S.W. 



Pitchblende 



354-05 



Joachimsthal "^ Given for 



Samarskite 



47-10 



Sweden ) comparison. 



Thallium blende 



375 



Locality unknown. Activity 

 may be due to the pro bable 

 association of uranium 

 minerals. 



The Australian minerals whose activities have been 

 recorded in the table are with one exception monazites. 

 These monazites frequently occur in the tin fields through- 

 out Australia, and on account of their thoria contents have 

 lately become of commercial importance. Monazites are 

 found to a less extent in situ, at Torrington in a decom- 

 posed granite, and at Warialda embedded in a lode of 

 bismuth carbonate. 



