250 Examination for Thallium and Indium. 



it was thought worthy of an examination. This specimen 

 yielded neither zink nor thallium or indium. 



14. Greenookite. Sbawneetown, Illinois. 



Aside from cadmium and zink this mineral yielded no lines. 



15. Granulated Zink. Bethlehem, Pennsylvania. 



This is a remarkably pure zink made chiefly from calamine. 

 It contains no thallium or indium. 



16. Metallic Zink. La Salle, Illinois. 



This zink is made from the blendes of Northern Illinois and 

 Wisconsin. It showed the presence of manganese but no thal- 

 lium or indium. 



17. Soot. 



The accumulation of soot from the flues where anthracite coal 

 from Pennsylvania had been employed as fuel was found to con- 

 tain lithia, potassa, lime, iron, and sulphur, but no thallium or- 

 indium. 



18. Sediment from Zink. 

 In the refinery of gold by the zink process, under the direc- 

 tion of Mr. McCulloh at the Mint in Philadelphia, a consi- 

 derable residue accumulated in the dissolving tanks which was 

 found to contain abundant traces of manganese, copper, lead, 

 and thallium. The zink was imported from Germany. 



It will be seen from these examinations that in twelve spe- 

 cimens of American blende, from widely separated localities, to 

 wit : Colorado, Cuba, New Hampshire, and Pennsylvania, no 

 thallium or indium was found, but that it was immediately dis- 

 closed in a sediment from German zink. It would be singular 

 if indium were to be confined to a few European minerals. 



My thanks are due to Mr. H. B. Cornwall for assistance in 

 preparing the ores for examination before the spectroscope. 



