408 Miscellaneous Intelligence. 



4. Obsidian. — At the volcano of Sotara, between Bogota and 

 Quito, M- Humboldt observed the neighbouring plains ofJulumeto 

 covered vi'ith balls or tears of obsidian, thrown out by the volcano. 

 These were frequently tubercular on the surface, and occurred of 

 all shades of colour, from the deepest black to the most perfect and 

 colourless transparency. These varieties of colour were not ac- 

 companied by any swelling or want of compactness. The speci- 

 mens were mixed with fragments of enamel, resembling Reaumurs' 

 porcelain, and to which unfused pieces of feldspar adhered.— ^nw. 

 de Chim. xxvii. 117. 



5. Locality of the Columbite. — Dr. Torry, of New York, has dis- 

 covered Columbite, massive and crystallized, in a rock from Had- 

 dam, (Connecticut), and he thinks it is probable that the specimen 

 in the British Museum, in which Mr. Hatchett originally discovered 

 columbium came from the same place. That specimen is, said to 

 have been found in New London, not above 25 miles from Haddam, 

 and though a much larger piece than any as yet found at the latter 

 place, yet he observes, it is probable that a close examination will 

 furnish finer specimens than any that have been found there. 



6. Erlanite, a New Mineral. — This mineral was observed by 

 Breithaupt, in 1818, in different parts of the Saxon Erzgebirg. It 

 forms a part of the oldest gneiss formation, and is always mixed 

 with more or less mica. Between Grose-Pbhle and Erla there ex- 

 ists a bed of it, at least 100 fathoms in thickness. It has been 

 used for upwards of 200 years as a flux by the iron smelters, and 

 until its examination by Breithaupt it had been uniformly mistaken 

 for limestone. 



Characters — Lustre, feeble shining toduU ; streak, shining with a 

 fatly lustre ; colour, light greenish grey ; streak, white massive : — 

 sometimes compact, sometimes in small and fine granular distinct 

 concretions ; fracture, in some specimens foliated, in others splin- 

 tery and even; structure distinctly crystalline, but as yet no regular 

 cleavage obtained; hardness between that of apatite and actionolite; 

 specific gravity from 3 to 3.1. Before the blow-pipe readily melts 

 into a slightly coloured, transparent, compact bead. It resembles 

 gehlenite more than any other mineral; is distinguished from fel- 

 spar by greater specific gravity, and from saussurite by inferior 

 specific gravity and hardness. It is composed, according to Gme- 

 lin, of 



Ann. Phil N. S. viii. 339. 



