374 General Notes. [April 
the combination of these two molecules in different proportions 
the various members of the group are formed, and by calculation 
the proportionate amounts of each present in any given case can 
readily be determined from the amounts of calcium and sodium 
found by analysis. Bastonite, a micaceous mineral character- 
izing certain sandstones and arkoses, is supposed by Renard to 
very similar to vermiculite, which Tschermak ene as an 
altered phlogopite. Its analysis yielded Klement 
SiO, AlO, FeO, FeO MnO CaO MgO K,O Na,O H,O 
36.013: 2004. 20.08 373 trace’ Ogs 796 3.07 0.23 ~ 6.98 
—— According to the abd danse of Nordenskiold,? the pecu- 
liar fluid inclusions in Brazi n topaz, to which Dana gave the 
name ‘brewsterlinite,” are, ab Teati in some cases, inclusions ofa 
hydrocarbon, probably of the naphtha group. Schuster? has 
discovered that the draunzte from the manganese mines of Jakobs- 
rg, in Wermland, Sweden, is probably isomorphous i 
tallization with hematite and ilmenite. Its analysis yielded 
Igelstrom,s— 
SiO, MnO FeO Mg0O.CaO PbO (0) 
8.7 80.23 * t33 0.95 8.65 8.17 
If the iron, Tapen, calcium, and lead be supposed to replace 
manganese, the composition of the mineral may be reproar 
by the formula 11Mn,0,.3MnSiO,, corresponding very nearly to 
the result reached by Rammelsberg in his analysis of the ratnika 
from Elgersburg. 
Crystallographic News.—Recent measurements of crystals 
of vanadinite from Pinal County, Arizona, have yielded Mr. 
Penfield 5 results agreeing closely with those obtained by Urba® 
in his investigations of Carinthian crystals. Endlichite? [ Pb,Cl 
a + Pb,CI(VO,),] from the Sierra i 
ounty, New Mexico, was also examined. The axial ratio, as 
rhombohedral symmetry. The twinning laws of copper are also 
investigated, and the article concludes with plates containing fifty- 
* Min. u. ei Mitth., Dte 1886, p. 1. 
2 Neues Jahrb. f. Min., r e Su 
3 Min. u. Petro Z. g. Mitth. 
5 Amer, Jour, Sci., aitain oad 8 
ri iy j ; 
uralist, Notes, uly, 1885, 
J man p 709. 
