E. 8. Dana—Spodumene from North Carolina. 181 
a 100 te q 332 3 
b 010 it p 111 2 
€ 001 z 261 —6- 
i 320-3 g 681 —8-$ 
A Pass s | a tee on 42 
m 120 42 u 243 4.9 
n 1380 €8 oo ee 4-2 
r 441 4 a 231 3-3 
aes 7 ee y 561 6-8 
Se se above planes 4, s, q, % 9, 6 %, &, @, y, are new to the 
* Catortnanial the crystals, while uniformly perfectly trans- 
parent, do not in any case allow of even tolerable measure- 
Dana with the hand goniometer on the large crystals from 
Norwich, Mass. On this account these angles are accepted as 
the basis of calculation, viz: 
cra 001.100=69° 407 
I,J 110,.110=93° 
cae 001,021=50° 
The corresponding values of the axes are :— 
a=1:000 
Some of the more important angles (supplement angles) for 
Bie widen planes, calculated from the above axes, are as 
l 
te, (110)=43° 30” b (010) .u (243)=40° 16” 
WORE ((820)36 «ay (561)=53° 27 
« Am (120)=25 2 1(110) sg (681)=10 18 
«an (130)=11 33 “ne (241)=21 46 
«ng (BD=s1. 3 “Au (243)=63 8 
whe (He Hap (i1ij=16 34 
«he (261396 6 I(i10).s (441)=17 
“ 48 (441)=41 48 “9! (321)3384 40 
« Ar (221)=45 43 « q =(332)=44 22 
Hag (82)=49 51 “ p (i11)=59 3 
«  ,p (111)=58 15 “ y (561)=14 54 
“ ne (81x34 2 ‘  @ (331)=32 .14 
tne, CaM. “ .e (941)=32 35 
As has been stated the measured angles are only rough ap- 
proximations, arn serve however to determine the several 
planes. As far as needed for this fs in conjunction with the 
obvious zonal selations they are as follows :— 
I(i10).s (441)=18° " T(110)ag et 10° 
r (221)=35 241)—22 
q ae : u (243)=62 
p (111)=60 p (111)=75 
y (561)— S118" b (01) at (241)=27 
a (231)=32 (231)=34-84° 30’ 
r (221)=45-46° 
