178 WN. von Kokscharov on the Clinochlore of Achmatowsk. 
Also, # for the inclination of the clinodiagonal terminal edge 
on the axis a; », for the same on the diagonal 6; 9, for the inclin- 
ation of the orthodiagonal, terminal edge on she. axis a; X, for 
the inclination of a face of P on the clinodiagonal section; Y, ibid 
on the orthodiagonal section; Z, ibid on basal section. 
And also: ace Se AP and ate vf, for the corresponding angles in 
the negative hemipyramid :—we then find 
@ 2) S6= 2477156 = 1: 1°73195* = 62° 50’ 48” 
X = 60° 44’ ¥=48* 5 Balt? GF 
X= 70" 22! e317 1 Y Abr Fa eg 
ee PEG Of o —49° 32’ 
o—= 60" OC fl 24° 42) > = Ser, §/ 
angle o being 60°, therefore the plane angles of the basal 
‘tides are 120° and 60°, or when the acute angle is replaced, 
a regular hexagon. This hexagonal character is also strongly 
shown in the hee of the zone me. whose intersections with 
three crystals, which are common in the clinochlore ot Achma- 
towsk, have a still greater similarity to a ci aay pris 
It is also to be observed that the angle C, 62° 51, is ents half 
the angle of M: M, or 125° 37’—half of 125° 37’, being 62° 483. 
In the crystals, the hemipyramids of the fundamental series are 
mostly more or less striated parallel to their intersection with 
P(0), and seldom smooth and shining so as to afford good meas- 
urements. The faces of the clinodiagonal zone m-% , are rather 
smooth and lustrous; but the face P, and the planes of the zone 
m-3 are the brig test and smoothest. The following angles are 
obtained by calculation from the values of the axes given, except- 
ing those with an asterisk which are measured angles 
oP 102° 77 (102° 6/t) mm 125° 24 sh 140° 39’ 
oM 143° 57’ 182° 35/ cP 107926" 
on 163° 34’ uP 127° 43°" cn 150° 20° 
ot 122° 0/ 166° 14’ ct 1 8/ 
ou (over M) 130° 10’ wa 155° 49’ 48° 11’ 
- fees “ 121° 28/ ut 124° 337 ew (over x) 138° 30’ 
uh 118° 18? wP 114° 4’ 
“ah oy 127° 53’ uu 133° 24’ wi 152° 38’ 
=a 118° a2! (118° 28’¢) dP 118° 59’ (119° 5’+) wt 151° 297 
174° 58’ wh 142° 15’ 
pag yd 2° dt 124° 33’ we 170° 19’ 
mt 124° a (24? 4 't) dh 115° 56’ wn seat inf 
MP 1 sm ae Gis 57't) 
Mt ee 124° 4/t) 
MhiN7 
MM oa. ae (125° 88’) 
i: M= 125° 37’; M:P=118° 57’; 
ateccietingiics <7 ae 
