342 T. S. Hunt on some American Minerals. 
«bright orange-red color. The addition of tincture of galls to a 
solution which had been partly precipitated by hydrochloric 
acid, but was still feebly alkaline, gave a pure orange-colored 
precipitate, more dense than the last; the supernatant liquid 
blackened in the air; a strongly alkaline solution assumed a deep 
orange-brown color, but gave no precipitate. The precipitate in 
the slightly acid solution gave with ferrocyanid of potassium a 
bright reddish-fawn color, resembling persuccinate of iron. These 
reactions according to Rose are characteristic of niobic acid un- 
mixed with tungstic acid. The metallic acid from the Haddam 
columbite gave precisely similar reactions. 
The liquid filtered from the niobic acid, and holding in the 
form of sulphates, the soluble portions of the mineral, gave no 
precipitate with sulphuretted hydrogen ; it was boiled witha few 
rops of nitric acid, and mixed with ammonia, which gave an 
orange-fawn colored precipitate, that became black on the addi- 
tion of hydrosulphate of ammonia; the filtrate was not affected 
by phosphate of soda. The precipitate was dissolved in hydro- 
chloric acid, boiled with some nitric acid, and again precipitated 
by ammonia; the filtrate was not disturbed by hydrosulphate of 
ammonia. e orange colored precipitate was now digested 
with a solution of carbonate of ammonia, which dissolved a por- 
tion and assumed a yellow color; on filtering and boiling the am- 
moniacal solution, a yellowish matter separated, which was dis- 
solved by dilute hydrochloric acid, and thrown down by ammo- 
nia as a lemon-yellow flocculent precipitate, which became green- 
ish-black on ignition, and gave before the blowpipe the reactions 
of oryd of uranium. With microcosmic salt in the outer flame 
it yielded a yellowish-green glass, which became bright green 
in the inner flame, and on cooling remained emerald-green and 
transparent. 
The portion not dissolved by the carbonate of ammonia was 
dried and ignited ; it dissolved in hydrochloric acid with an evo- 
lution of chlorine. Oxalic acid being added to the solution, @ 
pale rose-red granular precipitate fell; ammonia was now a 
in slight excess, and a farther portion of oxalic acid to restore the 
acid reaction. After some hours, the precipitate was collected, 
washed, and ignited; it was fawn colored, and readily soluble m 
nitric acid diluted with fifty parts of water. The concentrated | 
nitric solution gave with sulphate of potash a small portion of a 
crystalline double salt, insoluble in a solution of the sulphate, and 
the oxalic solution gave a minute portion of a similar precipitate. 
The two being united, were dissolved in boiling water, and de- 
composed by potash; the precipitate was chesnut colored after 
ignition, and was partially soluble in dilute nitric acid, leaving 
chesnut-brown residue. ‘These characters indicate oryd of cervum 
mixed probably with lanthanum and didymium. ‘The substance 
