302 Hidden and Mackintosh — Occurrence of Poly erase. 



half strength, with 2 grm. of ferric sulphate (either in the 

 form of iron alum, or ferrous sulphate oxidized in concentra- 

 ted solution by about 0*3 cm 3 of nitric acid), and 3 cm 3 of 

 nitric acid. A trap, of the form described, is hung in the 

 neck of the flask, and the liquid is boiled until the steam 

 which escapes no longer gives to red litmus paper, after two 

 minutes' exposure, the characteristic gray blue due to traces 

 of iodine. Then 1 cm 3 more of nitric acid is added, and the 

 test for iodine again made. When no iodine is found in the 

 escaping vapor, silver nitrate is added in excess to the contents 

 of the flask, the precipitate is settled, collected in a perforated 

 crucible on asbestos, dried, and weighed as silver chloride. 



Second Method. — The solution of the chloride and iodide 

 contained in an Erlenmeyer flask is diluted to 400 cm 3 ; 10 cm 3 

 of sulphuric acid of half strength are added, and the vapor 

 from 2 grm. of sodium nitrite acted upon by dilute sulphuric 

 acid (preferably in a simple generator, such as is described 

 above) is passed with reasonable rapidity into the agitated 

 solution. The liquid is boiled until colorless, and still further 

 until litmus paper placed in the steam gives no reaction for 

 iodine after an exposure of two minutes. The contents of the 

 flask are treated with silver nitrate, and the precipitated chlo- 

 ride is treated exactly as in the first method. 



Both methods are convenient and precise. 



Art. XXXVIII. — On the occurrence of Poly erase, or of 

 an allied species, in both North and South Carolina; 

 by W. E. Hidden and J. B. Mackintosh. 



A FEW crystals of the mineral here described were brought 

 to the attention of one of us while prospecting in the summer 

 of 1888 for ores of thoria in the zircon region of Henderson 

 County, North Carolina. The new thorium-phosphate (Auer- 

 lite)* had lately been discovered in that neighborhood and this 

 yttrium-uranium mineral was considered by its finders to be 

 identical with it. Its yellow exterior alteration bore a great 

 resemblance to auerlite, particularly to that variety found on 

 the Price land, but its form, density, dark interior color, *and 

 bright resinous fracture suggested a closer relation to euxenite, 

 poly erase or samarskite. The locality was visited and the work 

 of developing it promptly commenced. 



In an announcement of a new occurrence of xenotime-cyrto- 

 lite, printed in this Journal (Nov., 1888), the first notice of this 



*This Journal, Dec, 1888. 



