228 -Mineralogical Notices. 
The green base, Delesse shows is not hornblende or diallage, 
but probably —— feldspar discolored by oxyd of iron and 
magnesia. he variolite of La Durance contains at times ser- 
geome and may re observed in some places graduating into 
this 
Varslite, euphotide and serpentine are usually associated in the 
same region. The mean composition of the rock from La Du- 
rance is 
Si -”l r F Mn Ca ge Na K 
5279 11°76 trace 11:07 trace 590 901 307 1:16, ign. 4-38-9914 
The rock is intersected by seams of epidote, quartz or carbonate 
of lime, sa sometimes the globules are broken across by a vein 
and the alves more or less displaced. 
The pep formed from the variolite had the density 2:288, 
showing a great diminution from that of the unaltered rock, 
which is about 2-9 
This variolite receives a fine polish and is worked into orna- 
ments of various kinds. 
Orthite from East Bradford, Chester Co., Pennsylvania.— 
‘ts mineral was sent by Mr. Thos. Seal, of Philadelphia, to 
. D. Dana, and by the latter to Rammelsberg. Analysis af- 
forded this chemist (Pogg. Ann., lxxx, 285 
Si Al 6 Me 
8186 1687 858 1226 2127 240 1015 1°67, ign. 111=L0117 
Oxygen,1655 788 107 272 315 035 288 0°65 
This gives the oxygen ratio for the protoxyds, peroxyds and silica 
9-75 : 8:95: 16°55, and the formula R* $i+#Si, which agrees with 
the recent analysis of orthite by Rammelsberg, making the min- 
ral analogous in composition to garnet. 
Rutile—The following are analyses of rutile by A. Demoly 
(These de chemie, presentée 4 la Faculté des Sciences de Besan- 
gon, and Lieb. and K. Jahresb., 1849, 728) :— 
i Fe Mn S 
1 96-41 1-63 0-18 1:83=100 
2. 96°45 162 Or14 1-79=100 
3. 96°43 1:62 O11 184=100 
kite—N. von Kokscharov has recently investigated the 
itattization of Brookite of the Ural and the following are 4 
rt of the results obtained (Pogg. Ann., Ixxix, 454):—M:M= 
90° 50’ and 80° 10’. Angles of octahedron P, 101° 35’, 115° 
43’, 111° 26’; of QP, 87° 12’, 104° 54’, 142° 21’: of 2, 135° 
37’, 101° 3’, 95° 224’; of horizontal prism, 2Pac , 65° 48/ and 
124° 12/; 4B. , 76° 55’ and 104° 5’; 4 poe, 148° 394’, 31° 20%; 
dpa, 121° 244" 58° 354’; of vertical prism, op2, 45° 383’, 
134° 21H, — gravity of the crystals according to Mr. 
F'rédmann, 
