440 CAPTAIN W. DE W. ABNEY AND DR. T. E. THORPE ON PHOTOMETRIC 
Spots I and 10 are in the line of the apparent direction of the moon’s path across 
the solar disc ; it will be noticed that on repeating the readings one area has gained 
as much in intensity as the other has lost, whereas spots 4 and 7 which are at right- 
angles to the moon’s apparent motion, have remained practically unchanged in 
intensity. 
Table II. gives the value of Mr. Forbes’s readings with the integrating photo¬ 
meter. 
Table II.—Readings with the Integrating Photometer reduced to values of 
o o o 
Light-Intensity. 
No. of readings. 
Ammeter reading. 
Value of light at 
1 foot from screen in 
Siemens’ units. 
Approximate time of 
readings from 
heerinniner of totality. 
1 
] 05 
0-029 
seconds. 
3 
2 
103 
0-026 
12 
3 
1-02 
0-024 
30 
4 
0-99 
0-022 
45 
5 
1-00 
0-022 
70 
6 
1-04 
0-027 
94 
7 
1-035 
0-026 
120 
8 
104 
0-027 
147 
9 
105 
0-029 
184 
10 
1-05 
0029 
206 
Average 
light = 0'026. 
The measurements with the equatorial photometer clearly show that the visual 
brightness of the corona of the 1893 eclipse varied within comparatively wide limits, 
and that, at all events close to the moon’s limb, there were marked differences in 
local intensity. The readings of spots 1, 2, 3, and 10, 11, 12, which are at the 
opposite sides of the lunar disc are fairly concordant among themselves. Spot 7, 
which was comparatively close to the limb, was probably affected by the proximity 
of a prominence; it will be noticed that the readings were repeated at an interval of 
more than a couple of minutes and are in substantial agreement. 
It may here be stated that anything in the nature of personal bias on the part of 
either observer was impossible from the very manner in which the work had to be 
done ; Mr. Gray, of course, could not see the comparisons actually made, nor could 
Dr. Thorpe have any knowledge of the readings of the current strength at the 
particular moment of comparison; each portion of the joint work was therefore 
wholly independent. If the several values taken in the direction of the poles and 
equator are grouped as before, excluding Spot 7, for the reason above given, the 
averages, when treated as in our former paper, will be found to afford a curve almost 
