Miscellanies. 203 
lustre. The angles quoted were obtiingd by Prof. Shepard and 
Mr. Dana; those of observation by the former gentleman from the 
crystal represented in fig. 2, and those of calculation by the latter. 
The faces of this crystal, though quite bright, were somewhat curved, 
and consequently there was considerable variation in the angles ob- 
tained with the reflective goniometer. 
Angles by the Reflective Goniometer. Angles from calculation.* 
Pié= 102° 45’ ” 103° 4 
FR: M 100 99 45 
Oe =e a 121 46 
Pia” 140 10 138 38 
Mie 133 30 133 30 
M:é 138 138 29 
M:é@ 161 17 
ése 106 50 107 6 
éia 142 30 143 33 
€:é 118 117 47 
Eta 141 50 
ere 92 20 90 : 
éia 100 15 
2:8 131 22 
ese 126 25 126 27 
a: (over summit) 92 30 93 30 
The description of Fig. 2, after the notation of Naumann, is as 
Ws: 
woPo.oP.aP’o.aP’2.Po.P’o.—P.—Po. 
é Mi se =. € a 
* The observed angles assumed as data for the calculation of the interfacial 
angles of the crystal are as follow: M: é =136° 30'; €:4 =140° 10'; €: & =126° 957 
The axes, a:b: c ='9277:1:1:024. 7 =76° 18’. 
