Mineralogy and Petrography. 1113 
have discovered that the brown massive mineral from Newbury, 
ass., and regarded by Dana as garnet, is vesuvianite. It has a 
specific gravity of 3.55 and a composition :— 
SiO, AlO, FeO CaO MgO K,O Na,O MuO, P,O; 
35.93 14.77 8.91 389.46 .18 44 36 tr. tr. 
—A hard black mineral occurring at Rome, Mass., in little octa- 
hedra, has been examined by Crosby and Brown,! with sufficient 
accuracy to lead them to declare it gahnite. 
MINERAL SYNTHESES.—Dollter? has effected the synthesis of a 
large number of micas by fusing together aluminium-bearing sili- 
cates and metallic fluorides. The hornblendes yielded biotite when 
fused with sodium and magnesium fluorides. The alumina-free 
hornblendes gave olivine or augite. Garnets yielded meroxane. 
Micas of different kinds were obtained by fusing K, Al, SiO, with 
sodium fluoride alone; or with this salt and potassium fluosilicate 
or magnesium silicate, with or without the addition of ferrous 
Silicate. All the micas thus produced were decomposed when the 
temperature of the mass was raised toa white heat, and olivine, 
augite or scapolite were formed. Muscovite was obtained from 
andalusite by fusing it with potassium fluosilicate and aluminium 
fluoride, and zinnwaldite, when a little lithium carbonate was 
added to the mixture. Many other points of interest are found in 
the paper, which will undoubtedly prove of value in discussing the 
paragenesis of minerals in rock masses.—Among the other minerals 
produced artificially within the past few months, attention may be 
called to rhodonite and tephronite, which Gorgen? obtained by heat- 
ing to a high temperature, in the presence of water vapor, a mix- 
ture of manganese chloride and precipitated silica. Wollastonite‘ 
was produced when calcium chloride was used instead of the man- — 
span compound. Barite, celestite and anhydrite were obtained * 
y fusing the corresponding amorphous compounds in the chloride 
of some metal.—Bourgeois® fused metallic tin with copper oxide 
and got crystals of cassiterite.—Dufet ” prepared pharmacolite by 
allowing solutions of calcium ê nitrate and di-sodium arsenate to 
diffuse slowly into each other. 
_ MISCELLANEOUs.—Julien believes that the rate of decompo- 
sition in pyrite depends upon the amount of marcasite present in it 
'Ib., p. 408. 
ia rae und Petrog. Mitth., x., p. 67, and Neues Jahrb. f. Min., ete., 
+ B. p. 8. 
? Bull. Soc. Franç. d. Min., X., p. 264. 
t Ib., x., p. 271. — 6 Ib., X., p. 284. 
* Ib., xi., p. 58. 1 Tb., xi., p. 187 
e Ann. N. Y. Acad. of Sci., iv., July, 1888.4 
