2098 , General Notes. [March, 
both orthorhombic aragonite! and monoclinic leadhillite? become 
uniaxial when sufficiently heated. 
MINERAL SynTHEsIS.—Nearly everything heretofore done in 
the way of artificially reproducing natural minerals and their as- 
sociations in rocks has been produced in France (vid. NATURALIST, 
July, 1883, p. 780). Here, however, the results attained have 
been very interesting and important, and it is to be noticed 
with pleasure that the broad field which the researches of the 
French investigators have shown to be so fruitful is beginning to 
be successfully cultivated in Germany. Professor Doelter, of 
Graz, commenced, in connection with his colleague, Dr. Hussak, 
by studying the effects produced on various silicates by subjecting 
them to the action of different molten rocks.’ Augite yielded 
but small results, while hornblende was partially dissolved and 
changed to an aggregate of opaque grains and microlites of 
augite, as is often. observed in many volcanic rocks. Mica, gar- 
net, olivine, quartz, feldspar, zircon and cordierite were treated in 
same manner with different results, which cannot here be 
enumerated in detail. 
when melted and again allowed slowly to cool, produced meionite, 
melilite, anorthite, lime-olivine, lime-nepheline, hematite and spi- 
nell, together with more or less amorphous matter, but no trace of 
the original minerals ever appeared. The fusion of mixtures of the 
substances entering into the composition of garnet yielded no 
better results. It would therefore appear that something more 
than simple dry fusion is necessary to produce these two minerals. 
Doelter has still more recently busied himself with synthetical 
experiments on minerals of the pyroxene and nepheline groups. 
The lime and potash so often observed in the latter are probably 
isomorphous mixtures, since small amounts of Ca Al, Si, Os and 
K, Al, Sig Os, when melted with the typical nepheline molecule, 
Na, Al, Si, O; gave homogeneous crystalline masses having all 
e properties of nepheline. In regard to the aluminous pyrox- 
enes, Rammelsberg holds that the Al, O, and Fe, O, are present 
Klein: Nachrichten d. Kön. Ges. d. Wissensch, ing , 
md Neues Jahrbuch für Min., etc,, 1884, 11, p AONA a 
> s Mügge: Neues Jahrbuch für Min., etc., 1884, I, p. 65. 
~ Neues Jahrbuch für Min., etc., 1884, pp. 18-44. 
aa Jahrbuch fiir Min., etc., 1884, 1, 158-177. 
Zeitschrift fiir Krystallographie, 1884, 1x, 322-332. 
