252 Mineralogical Notices. 
Si Al fa Mn Ca Me H 
1. 3682 1694 13°32 1711 0°56 1484 ° 0°86 0-28=100°78 
2, 8755 15°99 930 319 056 1683 023 1360 022 180= 9927 
The proportion of silica is larger than in other allanites, and 
that of oxyds of cerium and lanthanum less. Credner observes 
that Scheerer obtained the oxygen ratio for protoxyds, peroxyds 
and silica 2:3: 5, but that his result agrees more nearly with 
2:3: [Scheerer’s formula for his allanite was 3k% Si+28 Bi, 
corresponding to the ratio 3: 2:5. Rammelsberg has since eX- 
amined the orthite of Hitteroe and obtained the ratio 1:1: 2, 
by special investigation with respect to the state of oxydation of 
the bases. If so much of the iron in the first of the preceding 
analyses be considered peroxyd as will give the ratio 1: 2 between 
the oxygen of the alumina and silica, the other bases in the analy- 
sis being taken as protoxyd, make very nearly the amount neces- 
A 
: ~ sary to afford the ratio 1: 1:2; calculation giving for the oxygen 
rae tion of some 
: 933, 323.)— 
5 h y from Montreuillon, dis- 
: \| dodecahedral 
pat s, and lamellar macles of white orthoclase, a little re 
er sseminated through a whitish or 
- e.—b, a variety from near Sau- 
© ew (Cote Or 
= ay ‘i 
; ey: 4 et Si Al Fe Mn Ca K, Na, Mg, ign. 
we 6 a 150° 29 o4 (diff)88 12 =100 
; Rey 3 6% 176 129 2° traces O-4 OT sere =100 
oon! © 2 Feldspar of a Euphotide ; a, from Mount Genévre; b, from 
tae - Odern in the Vosyes.—The feldspar in each case is in lamellar 
oe J *\macted crystals of the triclinic system, and has a white or green- 
¥ “ssh color. a3 bit : 1 f 
et * Si X16 OMn’ Bes Ga =62OMg Na K_~ ign 
44a. (mean) 49°73 2965 trace 085) 1118 056 404 024 375 =100 
*- b .* 6523 2424 | Felil 686 148 483 3803 305 = Mclrsd 
aon ee “The specimens were not wholly free from tale and minute veins 
“of serpentine matters. Tie latter had a neater cleavage than 1s 
*. . usual *ygith tthe feldspar of euphotide, yet was impure also Wil 
a: 
ata large proportion of silica and alkalies W 
ime explains the neater cleavage. H¢ d 
Bi of 0. 0, the 
eldspar of euphotide 
ité as Boulanger su 
a 
