670 
MR. H. E. ROSCOE ON A METHOD OF MEASURING THE 
June 17th, 1873 (continued). 
Clock. 
Hand. 
Time. 
n. 
Mean 
reading. 
I. 
I 
n 
Time. 
n. 
Mean 
reading. 
I. 
I 
n 
k m (■ 
9 20a.m. 1 
5- 3 
6- 9 
145 
138 
0-55 
0-61 
0-104 
0-088 
h m 
9 20 a.m. 
No obse 
rvations. 
Mean 
0-096 
10 20 „ | 
6-9 
9-6 
60 
10 
1-21 
1-68 
0-175 
0-175 
10 20 „ | 
5 
5 
10 
119 
118 
20 
0- 75 
0-76 
1- 58 
0-150 
0-152 
0-158 
Mean 
0-175 
Mean 
Diff. 
0-153 
+ 0-022 
11 20 „ j 
5- 3 
6- 9 
9-6 
153 
145 
129 
0-47 
0-55 
0-68 
0-088 
0*080 
0-071 
11 20 „ j 
5 
5 
10 
150 
153 
117 
0-50 
0-47 
0-76 
0-100 
0-094 
0-076 
Mean 
0-080 
Mean 
Diff. 
0-087 
—0-007 
12 20 p.m. | 
10-2 
17-1 
154 
125 
0-45 
0-71 
0-044 
0-042 
12 20 p.m. | 
10 
15 
156 
137 
0-43 
0-62 
0-043 
0-041 
Mean 
0-043 
Mean 
Diff. 
0-042 
+ 0-001 
1 20 „ | 
5- 3 
6- 9 
124 
95 
0-71 
0-89 
0-134 
0-129 
1 20 „ 
No obse 
rvations. 
Mean 
0-132 
2 20 „ | 
2-8 
3-6 
5-3 
151 
131 
113 
0-49 
0-66 
0-78 
0-175 
0-183 
0-147 
2 20 „ | 
3 
5 
5 
145 
123 
132 
0-55 
0-72 
0-66 
0-183 
0-144 
0-132 
Mean 
0-168 
Mean 
Diff. 
0-153 
+ 0-015 
3 20 „ | 
10-2 
17-1 
155 
142 
0-44 
0-58 
0-043 
0-034 
3 20 „ | 
10 
15 
153 
146 
0-47 
0-54 
0-047 
0-036 
Mean 
0-039 
Mean 
Diff. 
0-041 
-0-002 
4 20 „ | 
10-2 
17-1 
20-2 
134 
90 
63 
0-64 
0- 91 
1- 17 
0-063 
0-053 
0-058 
4 20 „ | 
10 
15 
20 
138 
127 
69 
0-61 
0- 69 
1- 09 
0-061 
0-046 
0-055 
Mean 
0-058 
Mean 
Diff. 
0-054 
+ 0-004 
5 10 „ j 
10-2 
17-1 
20-2 
31-7 
158 
146 
123 
65 
0-41 
0- 54 
0-72 
1- 14 
0-040 
0-032 
0-036 
0-036 
5 20 „ | 
10 
15 
20 
30 
158 
153 
120 
73 
0-41 
0-47 
0- 75 
1- 03 
0-041 
0-031 
0-035 
0-034 
i 
Mean 
0-036 
Mean 
Diff. 
0-035 
+ 0-001 
