664 
ME. H. E. EOSCOE ON A METHOD OE MEASUEING THE 
Self-registering instrument. 
Expe- 
riment. 
Time. 
n. 
Mean 
reading. 
I. 
I 
n 
h m f 
5-3 
169 
0*26 
0*049 
I. 
11 0 a.m. 
10-2 
154 
0*45 
0-044 
1 
17-1 
144 
0*56 
0-033 
* 
Mean 
0-042 
r 
9-6 
145 
0*55 
0-057 
II. 
2 0 p.m. < 
10-2 
138 
0*61 
0*059 
1 
17-1 
60 
1*21 
0-070 
Mean 
0*062 
[ 
5-3 
155 
0-44 
0*083 
III. 
2 30 p.m. ■{ 
6*9 
150 
0*50 
0-072 
1 
9-6 
143 
0*57 
0-059 
Mean 
0-071 
f 
3*6 
168 
0*28 
0-077 
IY. 
3 0 p.m. 
5*3 
162 
0*36 
0-068 
1 
6*9 
150 
0-50 
0-072 
Mean 
0*072 
r 
5-3 
160 
0*39 
0-073 
Y. 
3 30 p.m. \ 
6-9 
139 
0*61 
0-088 
1 
9-6 
121 
0-74 
0-077 
Mean 
0-079 
f 
9-6 
166 
0*31 
0-032 
YI. 
4 0 p.m. j 
10*2 
17*1 
161 . 
145 
0*38 
0-55 
0-037 
0-032 
l 
2.0*2 
130 
0-67 
0-033 
Mean 
0-034 
VII. 
4 30 p.m. | 
20-2 
31*7 
116 
68 
0- 77 
1- 10 
0-038 
0-035 
Mean 
0-037 
VIII. 
5 0 p.m. | 
17*1 
20*2 
137 
133 
0*62 
0*65 
0-036 
0-032 
Mean 
0-034 
Hand instrument. 
Time. 
n. 
Mean 
reading. 
I. 
I 
n 
h m (- 
11 0 A.M. j 
5 
10 
154 
133 
0-45 
0-65 
0-090 
0-065 
Mean 
0-078 
2 0 p.m..... 
10 
57 
1-24 
0-124 
Mean 
0-124 
2 30 p.m. | 
5 
140 
0-60 
0-120 
5 
137 
0-62 
0-124 
Mean 
0-122 
3 0 p.m. | 
5 
137 
0-62 
0-124 
5 
120- 
0-75 
0-150 
Mean 
0-137 
a 30 p.m. | 
5 
109 
0-81 
0-162 
5 
122 
0-73 
0-146 
Mean 
0-154 
f 
10 
131 
0-66 
0-066 
4 0 p.m. < 
15 
117 
0-76 
0-051 
1 
15 
65 
1-14 
0-076 
Mean 
0-064 
4 30 p.m. . . 
15 
59 
1-22 
0-081 
Mean 
0-081 ! 
5 0 p.m. . . 
15 
76 
0-99 
0-066 
Mean 
0-066 
The following Table shows that the values of the coefficient obtained at the under- 
mentioned varying hours of the day are sensibly constant. The mean value T&4 is 
therefore taken as representing the coefficient for the shade used in the determinations 
which follow : — 
