830 



SCIENCE. 



[Vol. II., No. 47. 



this district is an extremely variable hornbleiidic, 

 cliloritic, or micaceous schist, sometimes somewhat 

 gneissoid. This rock is used for building-purposes in 

 its finer varieties, which are composed of quartz and 

 biotite, with a silvery white mica, magnetite, apatite, 

 etc. Besides the quartz and biotite, the coarser 

 varieties frequently contain plagioelase, hornblende, 

 chlorite, apatite, epidote, pyrite, magnetite, garnet, 

 and rutile. The biotite is frequently more or less 

 altered to chlorite, and contains apatite, magnetite, 

 and sometimes infiltrated calcite. — [Proc. U. S. nat. 

 mus., vi. 159.) M. E. w. [553 



The bismuth deposits of Australia. — These 

 deposits are found in irregular quartz veins or ' reefs ' 

 in gray granite, and near its junction with tlie sur- 

 rounding porphyritic and schistose rocks. Tlie veins 

 are composed of irregular segregations of quartz, 

 holding bismuth, both native and as a sulphide, gold, 

 molybdenite, smoky quartz crystals, etc. These veins 

 occur only in circumscribed patches in the granite, 

 which has here been decomposed to a soft, friable 

 rock, the mica and felspar being much altered. 

 The native bismuth occurs in irregular bunches and 

 nests throughout the quartz, or in fissures traversing 

 the veins. These bunches vary in weight from a 

 half-pound to fifty pounds; and the metal is particu- 

 larly found associated with and incasing the crystals 

 of smoky quartz. Sometimes it is in needles in the 

 quartz. The walls of the segregations are charged 

 M'ith from thirty to fifty per cent of oxide of bismuth 

 for a distance from the vein of from eight inches to 

 two feet. 



Mr. Robertson, from whose paper the above ac- 

 count is condensed, states that tlie entire sale of bis- 

 muth has for years been monopolized by a few 

 London brokers, " known as the ' Bismuth ring,' — a 

 close and conservative institution formed for the jmr- 

 pose of controlling the supply and price of bismuth." 

 Tlie present consumption of the metal is about 

 seventy tons yearly; and it is stated that these de- 

 posits could easily produce that at a small expense. 

 In 1882 the market-price of bismuth was 6s. 8d. per 

 pound in Loudon. — {Trans, cjeol. soc. Glasc/ow, vii. 

 127.) M. E. w. [554 



MINERALOGY. 



Halite. — B. Wittjen and H. Precht have endeav- 

 ored to find the cause of the blue color in some vari- 

 eties of halite, and have arrived at the conclusion that 

 it is dependent upon some optical phenomena, possi- 

 bly connected with the presence of minute gas inclu- 

 sions. — {Berl. berichte, xvi. 1454.) s. i,. p. [555 



Rubellan. — This micaceous mineral has been in- 

 vestigated by M. U. Ilollrung, and shown to be very 

 various in its ijroperties. It occurs mostly as a de- 

 composition product of maguesian micas. It is by no 

 means homogeneous, and cannot be classed as a dis- 

 tinct mineral. By means of the microscope it could 

 be seen that crystals of the ordinary biotite form were 

 composed of lamellae of different degrees of decom- 

 position, showing all stages from pure mica to wholly 

 decomposed material. — {Mm. peir. mitth., v. 304.) 

 8. L. P. [556 



Parallel growth of zinc blende and tetrahe- 

 drite. — Specimens from Kapnik, Transylvania, have 

 been studied by F. Becke. The minute crystals of 

 tetrahedrite are deposited only upon the dull faces of 

 the blende crystals, and are of a later growth. They 

 have been deposited according to the following law: 

 the principal axes of the two minerals are parallel, 

 and the first or principal tetrahedron of tetrahedrite 

 is parallel to the second tetrahedron of blende. The 

 development of the tetrahedrite crystals is dependent 

 upon their location on the blende, being most sym- 

 metrical if deposited on a dodecahedron face, and flat- 

 tened if on a cubic face. A parallel growth of these 

 two minerals has been previously noted, but with the 

 first tetrahedron of tetrahedrite parallel to the first 

 tetrahedron of blende. — (Miii. petr. mitth., v. 331.) 

 S. L. P. [557 



lolite (cordierite ). — A. von Lasaulx has described 

 twin crystals occurring in a cordierite gneiss from 

 Laacher See. Twins of this species are of unusual oc- 

 currence, and have been observed with the prism go 

 P for composition face. The author finds, in addition 

 to twins according to the old law, compound twins, 

 part of the individuals being united according to the 

 old law, and part according to a new law with co p 3 

 for composition face. Twins united wholly accord- 

 ing to the new law were not observed. — {Zeitschr. 

 kryst.fVm.'ie.) s. l. p. [558 



GEOGBAPHY. 



(Arctic.) 



Arctic land. — F. Schmidt discusses the claims of 

 different persons, and especially Wrangell, to the dis- 

 covery of land north of eastern Siberia. Discovery is 

 hardly the proper word to apply to the record of re- 

 ports by the aborigines of that region. In fact, as Pro- 

 fessor Schmidt admits, Wrangell had his doubts as 

 to the accuracy of the report ; and liis opinion was ex- 

 pressed, sometimes with more, sometimes with less, 

 confidence, at different times. The first civilized man 

 to actually see what is now called Wrangell Island 

 was Kellett, who called it Plover Island, and made a 

 sketch of it from a long distance away, of which I 

 have a copy, and which is stated to be characteristic 

 by Capt. Hooper. The high land, with extensive 

 peaks, described by Kellett, like the PcUy Mountains 

 of the arctic coast, described by Dease and Simpson, 

 was simply one of those peculiar atmospheric effects 

 which occasionally deceive the most experienced arc- 

 tic travellers. The conclusion is, that no report of 

 new arctic land is worth any thing until it has at 

 least been very closely approached. — ( Isvestia imp. 

 geogr. soc, May.) w. h. d. [559 



Settlements on the Siberian coast. — Karzin 

 gives a most valuable list of the settlomenls, sum- 

 mer fishing-stations, camps of ivory-hunters, and 

 other iilaces, where human beings are to be found at 

 any season of the year on the coast of north-eastern 

 Siberia. The chronicles of the Jeannette expedition 

 might have been less gloomy, had the commander 

 possessed himself of some such directory before pro- 

 ceeding on that unlucky voyage. — {Isvestia imp. 

 georjr. soc, May.) w. ir. d. [560 



