1887] Mineralogy and Petrography. 373 
from gneisses, granites, rocky. basalt, sanidine bombs, 
graywackes, an s described the characteristic peca aniis 
of crystals obtained To these different so 
that the crystals occurring in gneisses aa present rounded 
contours, while those in granite are always defined by sha 
crystal planes. He proposes to make use of this fact in distin- 
guishing gneisses with granitic habit from true granites 
Mineralogical News.—Ka/iophilite is the name proposed by 
Mierish* for a new mineral occurring in colorless needles in one 
of the Monte Somma bombs examined by him in the course of 
his work referred to in the March number of this journal. It is 
a potassium nepheline. An analysis yielded,— 
» SiO Al,0, CaO K,O Na,O 
37.48 32-43 2.18 27.20 2.26 
The author supposes that ordinary nepheline may consist of mix- 
tures of the isomorphous molecules K,AI],Si,O, and Nas A Si0e 
since this mineral always contains more or less potassium 
= 
a 
Scapolite—In no manner can t ifference in the views of 
the two schools of ir rae ae chemists be better learned than 
by an examination of the papers relating to the discussion now 
of the scapolite group of minerals. In an article in the Mewes 
Fahrbuch, Rammelsberg? gives his reason for considering this 
group of minerals as consisting of molecular combinations of nor- 
mal- (meta-), half- (ortho-), and di- (bi-) silicates of sodium, cal- 
cium, and aluminium in certain definite proportions. Sarkolite, 
for instance, he regards as a molecular compound made up of the 
three ortho-molecules in the proportions 3Na,SiO,, 27Ca,SiO,, 
10A1,(SiO,),; and Metonite, from Mt. Vesuvius, as a similar com- 
pound, in which the meta-silicates arë present in the proportions 
of one ee to six of the ortho-silicates, as,— 
Na, Na,SiO, 
efel SO } + fo years: } + 20NaCl. 
3Al (SiO,), 3Al,(SiO,), 
schermak,* on the other hand, regards the momhers of this 
group (like those of the plagioclase group) as isomorphous mix- 
he calls respectively the meionite and mariolite molecules, y 
t Tschermak’s Min. u. Petrog., erie? a . 1886, p: 156. 
2 Amer. Jour. Sci., III. xx., xx., 1880, p 
3 Neues =_— ach f: Min., etc., Beil, ee iv., 1886, p. 610; also Sitzb, Berl. 
