44 Brush and Dana—Feairfield County Minerals. 
Calculated. Measured. 
a) @) @) 
cxZ, 001.110, = 81° 7 81° 
es 0014110, = 98° 53” 98° 52’ 
cap, 001.211, = 76° 35’ 76° 20’ approx. 
Inp, 110,211, = 29° 6’ 
exZ, 011.110, = 36° 53” 36° 50’ 36° 57’ (2) 
eal", 0114110, = 51° 33” 51° 24” 
eap, 011.211, = 47° 34’ 48° approx. 
ere’, 011.011, =109° 36’ 
pap’, 21211, = 82° 53” 
A comparison of the above angles with those given by 
Brooke and Miller for wagnerite shows that the two species 
are homceomorphou 
Thus in the three diametral zones, we have :— 
& 
Triploidite. Wagnerite (Miller). 
IAP, 110.110,=120° 54” g ag =122° 257 
CAa, 001 .% 100,= Ti" 46’ Cag = 1 537 
ere’, 011.4 011,=109° 36’ ere’=110° 6’ 
As the crystal of wagnerite is placed by Miller, the planes g, 
a, c and e have the symbols (120), (100) (001), (021) respect- 
ively. In the figure given by Miller the prism g 120 (= J, 
(110) triploidite) has the a development; it was made 
the unit prism aS dae: 
Unucal prone only point that could be established 
in si 2 ae Saal i tov of triploidite was the posi- 
tion of the axes of elasticity. The crystal used for measure- 
ment had the cinopinscaite so far developed that it could be 
examined directly in a Rosenbusch microscope. It was found 
that of the two axes which lie in the plane of symmetry, one 
very nearly coincides with the vertical axis, being inclined 
poe (see fig. 4) 8°-4°, and the other consequently is almost 
ormal to the orthopinacoid. The position of the optic axes 
oui not be fixed. Mh he crystals show no perceptible absorp- 
tion * ge cpr 
cal _composition.—Triploidite was analyzed by Mr. 
Penfield. This ae Ree os) was fo art to contain iron 
iron and manganese, as it was retain ed by the small aia 
of lime present. It was weighed with the iron, and afterwards 
was separated from the iron by means of ammonium molyb- 
