Page:Transactions of the Geological Society, 1st series, vol. 1.djvu/103

Retrogradations upon the acute angles of the terminal faces, answering to the acute solid angles of the primitive crystal.
Number of the modifi- cations.	Figure of the crystal	Angles formed by the meeting of the new planes with the terminal faces	Angles formed by the meeting of the new planes with the edges of 87°, 30′	Angles formed by the meeting of the new planes with those of the 5th modification.	Angles formed by the meeting of the new planes with those of the 6th modification.	Nature of the retrogradations
5th	Primitive crystal with the planes of substitution on its acute solids angle	98°, 5′	136°, 55′			Retrogradation by a single row
6th		124°, 56′	110°, 4′	153°, 4′		Retrogradation by 5 row in breadth and 3 laminæ in height
7h		134°, 22′	100°, 38′	143°, 26′	170°, 34′	Retrogradation by 2 rows
Retrogradations on the obtuse angles of the terminal face
Number of the modifi- cations.	Figure of the crystal	Angles formed by the meeting of the new planes with the terminal faces	Angles formed by the meeting of the new planes with the edges of 92°, 30′	Angles formed by the meeting of the new planes with those of the 9th modification.	Angles formed by the meeting of the new planes with those of the 9th modification.	Nature of the retrogradations
8th	Primitive crystal with the planes of substitution on its acute solids angle	105°, 7′	164°, 53′			Retrogradation by 1 row in breadth and 2 laminæ in height
9th		118°, 22′	151°, 29′	166°, 45′		Retrogradation by a single row
10h		148°, 23′	121°, 37′	136°, 44′	156°, 9′	Retrogradation by 3 rows