420 Mr. WHEWELL on the Classification 
OBLONG-PYRAMIDAL SYSTEM. 
Remarks. Example and Figure. Class. Combinations. 
Class IL. pP, qPm 
M.ILIV,V.} or pP, gP’m 
5 
__P2 is (Pr in Mohs, | Ob. Pyr'. Serpentine P, P2 | No. 1. pP, pPm 
and is ranged in Class IV. | Mohs, Vol. II. 33. p x 
Ob. P’. Mel.-glance P, P’3 | No. 2. pP, pP’m 
II. 30. p a 
N®. 3 and 4 differ’ from No. 3. qnP,gPn 
1 and 2 in that the faces| Fig. to No. 1. 
replacing edges belong to 
pP in 1 and 2, to qPn ees 
Jand q’Pn in 3 and 4. No. 4. qnP, qP’n 
Fig. to No. 2. 
Class III. | pP, gPr, q'P’r 
Mohs VI. 
Ob. P’. Olive-mal. P, Pr} No. 1. pP, pPr 
1 ey p o 
Ob. P'. Iron-ore P, P’r | No. 2. - pP, pP’r 
IL. 4. © 0p | M. VII. 1: 
P,Pr,yP’r| No.3. |pP,pPr,ipP'r 
p-0-~-n M. VII. 2, teas 
oP, Pr, P’'r| No.4. |@P,pPr, pP’r 
zo) p |M.VII.3. 
If the faces of a horizon- 
tal prism be rhombs, we 
can determine them. 
