262 MR. A. E. TUTTON ON A COMPARATIVE CRYSTALLOGRAPHICAL STUDY 
]\Iorphological Angles of Rubidium Magnesium Selenate. 
Angle measured. 
No. of 
measure¬ 
ments. 
Limits. 
Mean 
observed. 
Calculated. 
Differ¬ 
ence. 
coc 
100 : 001 = fi 
0 
t 0 
0 / 
- 
0 t 
74 46 
/ 
as 
= 
100 : 101 
--- 
— 
45 50 
— 
sc 
= 
101 : 001 
■- 
— 
_ 
28 56 
— 
cr' 
= 
001 : 201 
14 
63 
25— 63 
41 
63 35 
63 37 
0 
cs' 
= 
001 ; 101 
— 
— 
-- 
38 20 
— 
s'r 
= 
101 : 201 
— 
— 
— 
25 17 
— 
r'a 
= 
201 : loo 
— 
— 
— 
41 37 
— 
rc 
= 
201 : 001 
13 
116 
19—116 
32 
116 25 
116 23 
9 
f cq) 
= 
100 ; 110 
■ 
_ 
_ 
35 38 
1 PP' 
= 
no : 120 
--- 
— 
— 
19 28 
— 
J 
fj'h 
= 
120 : 010 
_ 
— 
— 
34 54 
— 
ph 
= 
no : 010 
6 
54 
20— 54 
26 
54 23 
54 22 
1 
PP 
= 
no : no 
20 
71 
4— 71 
30 
71 17 
* 
— 
[pp 
= 
no : no 
20 
108 
27—108 
54 
108 43 
108 43 
0 
^ cq 
001 : on 
54 
25 
39— 25 
52 
25 47 
_ 
qb 
= 
on ; 010 
10 
64 
11— 64 
14 
64 13 
64 13 
0 
1 
PR 
on : oil 
27 
128 
15—128 
36 
128 25 
128 26 
1 
ao 
100 : 111 
_ 
_ 
— 
49 3 
oq 
= 
111 : on 
— 
— 
— 
27 16 
— 
aq 
= 
100 : on 
— 
— 
— 
76 19 
— 
qu' 
= 
on : 111 
--- 
— 
-- 
34 34 
— 
o'a 
= 
Ill : 100 
— 
— 
— 
69 7 
— 
f CO 
001 ; 111 
_ 
_ 
_ 
34 33 
op 
= 
111 : no 
— 
— 
— 
43 7 
— 
cp 
= 
001 : no 
38 
77 
34— 77 
47 
77 40 
* 
— 
pd 
= 
no : 111 
1 
— 
57 42 
57 45 
3 
i o'c 
= 
in : 001 
1 
— 
44 35 
44 35 
0 
[pc 
= 
no : 001 
38 
102 
1—102 
30 
102 20 
102 20 
0 
J 
^bo 
— 
010 : 111 
_ 
_ 
70 14 
_ 
1 
os 
111 : 101 
— 
— 
— 
19 46 
— 
J 
[bd 
010 ; 111 
_ 
_ 
_ 
65 15 
i 
- o's' 
= 
111 : 101 
— 
— 
— 
24 45 
— 
r sq 
= 
101 ; on 
_ 
_ 
_ 
38 0 
_ 
<1P 
= 
on ;J10 
40 
86 
20— 86 
41 
86 30 
86 29 
1 
2}S 
= 
110 : lol 
— 
— 
— 
0 0 31 
— 
IPI 
= 
no : on 
40 
93 
21— 93 
40 
93 30 
93 31 
1 
r sq 
101 : on 
_ 
_ 
_ 
45 4 
_ 
iP 
= 
on : no 
39 
63 
21— 63 
39 
63 31 
63 32 
1 
< 
ps 
no : 101 
— 
— 
— 
71 24 
— 
= 
no : on 
39 
116 
19—116 
41 
116 30 
116 28 
2 
Cr’d 
201 : Ill 
_ 
_ 
34 48 
_ 
dp 
= 
Ill : no 
— 
— 
— 
92 37 
— 
i 
pr’ 
no : 201 
28 
52 
28— 52 
48 
52 37 
52 35 
2 
Ir'p 
= 
201 : no 
26 
127 
12—127 
38 
127 23 
127 25 
2 
Total number of measurements, 474. 
