A new system of Crystallographic Symbols. 261 
pose it to incline on the superior base, its symbol will be found to co- 
incide exactly with its situation. 15 expresses the decrement along 
the left basal edge, consequently it ought to be situated between the 
plane a? on the angle, and e? a plane on the edge ; where it really is. 
Fig. 3. Native Amalgam. Primitive form. Dodecahedron. 
Description. P e'|?|aa"|*}. 
Haiiy’s. PBBA‘'E!?E:. 
oer ee | 
& = 156° a = 135° 
e2 = 160° 53/ 86” a= 153° 296/ 6” 
a = 
144° 44’ 83” " 
Description referred to the cube as nucleus, e a? #2 a Pe’. 
Fig. 4. Idocrase. Prim. form. Right square Prism. 
s|*as|a|sje. 
Description. e'|?/P Pa? 
2 
2} 
Haily’s. 'G12G? MPAA AAA (2A? 2A? 1A? Be G) B, 
Ga “Eos at = 108° 18” 
e? = 153° 26/ 6” a? = 133° 18" 
a? = 165° 51’ a’ = 144° 44’ 
a = Me oe at = 1520 3 
at = 124° 30’ @ = 151° 52 
ae = =©118° 30’ 
Haiiy’s description has been made out on the supposition, that the 
plane a? instead of a, results from a decrement of a single row of par- 
ticles, Thus he makes the planes a?| 3|4|, intermediary, which ac- 
cording to the hypothesis adopted, are planes on the lateral angles. 
Fig. 5. Heavy Spar. Prim. form. Right rhombic Prism. P on P 
=101° 42’ 
6.3 
Description. eP e'|*|P aa'|®|* ae2 e?. 
3 
Haiiy’s. *G‘ M*H' «H+ PEA A A (EB? B?) P. 
e = 129° 9¥ a? = [141° 11’ 
e = 140° 51’ a‘ =: 158° 9 
6.3 
e* = 166° 53’ ae2 = 143° 6G 
a = 127°19 e? = 115°41’ 
2 = 121° 49 
