262 A new system of Crystallographic Symbols. 
Plane e? is situated on a basal edge, and inclines on a lateral 
face. Supposing the inclination on a basal plane, its symbol would 
be e?. 
63 
Plane ae2 is situated between the lateral angle, basal edge and 
basal plane. 6 and 3 will therefore refer to the basal edges, and 2 
to the lateral. 
Fig. 6. Calcareous Spar. Prim. form. Rhombohedron. PonP= 
105° 5’. 
Description. a?ee*. The same by Haiiy, e? B D?. 
1 
a? = 134° 36’ 35” et. = 160° 50 10" 
e = 142° 32’ 30” 
In this figure we see not the least resemblance to the primitive 
form. ‘The letters on its planes, make it apparent, that the lateral 
angles are replaced each by a plane, giving rise to the lateral faces of 
a Hexagonal prism, that the superior edges are truncated, and the 
lateral edges replaced, each by two planes. 
Fig. 7. Pyroxene. Prim. form. Oblique Rhombic Prism. Pon 
P=101° 5. Pon P=87° 42. 
Description. Pee Pa as a a°. 
Haiiy’s. M 'H'! 'G' P A 2A? E! 1E °F. 
e = 133° 51 a. cas 5. 144° Ob 
e = 136° 9 : a = 150° 
a = 147° 49/ a? = 137° 7 
This figure represents the crystal inverted, the dominant solid an- 
gle, being the inferior one in front. If placed in position, the planes 
whose symbols have an inverted curve below, would be situated on 
either of the inferior lateral solid angles, and would incline on the 
front faces. But their symbols are the same as those of the planes, 
diagonally opposite. These incline on a posterior face. The in- 
verted dash is therefore used according to the law already laid down. 
