DETERMINATION OF DEFLECTION OF LIGHT BY THE SUN’S GRAVITATIONAL FIELD. 307 
a. 
e. 
b. 
d. 
Eclipse j^lates. 
Scale plate. 
Comparison . 
)> 1426. 
„ 15i. 
„ 15^. 
„ 17i. 
„ 172. 
1^2. 
r 
+0-240 
+0-423 
+0-409 
+ 0-409 
+0-390 
+ 0-370 
+0-399 
+0-337 
+0-327 
r 
+ 0-168 
+0-207 
+0-207 
+0-207 
+0-207 
+0-202 
+0-207 
+0-202 
+0-202 
r 
+0-062 
+0-096 
+0-091 
+0-091 
+0-087 
+0-087 
+0-091 
+0-077 
+ 0-072 
r 
+ 0-062 
+ 0-096 
+ 0-091 
+0-091 
+0-087 
+0-087 
+ 0-091 
+0-077 
+0-072 
WTien these are applied to the values of the constants found frorn the normal equations, 
we find the following values of the scale of the several photographs and their orientation 
relative to the scale plate :— 
Scale Value. 
Orientation. 
Adopted Scale 
Orientation. 
From X. 
From y. 
From X. 
From y. 
Eclipse I. 
r 
-0-025 
r 
-0-010 
-0-237 
-0-265 
0-000 
r 
-0-251 
„ II. 
-0-009 
-0-024 
-0-045 
-0-107 
0-000 
-0-076 
„ III. 
+0-006 
+0-053 
+0-014 
+ 0-025 
0-000 
+0-020 
„ IV. 
-0-056 
+0-006 
-0-027 
-0-040 
0-000 
-0-034 
V. 
-0-055 
-0-006 
+0-008 
+0-031 
0-000 
+0-020 
„ VII. 
+0-050 
+0-017 
+ 0-0-32 
+0-050 
0-000 
+0-041 
„ VIII. 
-0.-014 
+0-031 
+0-008 
AO-006 
0-000 
+0-007 
Comparison IIoq . . . . 
+0-010 
+ 0-004 
+0-081 
+ 0-033 
+ 0-013 
+0-057 
,, 1426 .... 
+0-008 
+0-030 
-0-035 
-0-049 
+0-013 
-0-042 
l-h .... 
-0-063 
-0-085 
+0-155 
+0-086 
-0-084 
+0-120 
,, 152 ... . 
-0-065 
-0-075 
+0-003 
-0-035 
-0-084 
-0-016 
„ 17i .... 
-0-118 
-0-077 
-0-116 
-0-174 
-0-084 
-0-145 
„ 172 ... . 
-0-072 
-0-109 
+0-062 
+ 0-029 
-0-084 
+ 0-046 
,, I 82 .... 
-0-093 
-0-087 
-0-014 
-0-074 
-0-084 
-0-044 
The agreement in the scale values obtained from x and y is satisfactory. There 
appears to be a small difference m the orientations as derived from the two directions 
in the comparison plates. This is, however, of small importance in the determination 
of a. There is a difference of scale value from July 15-18 shown in both co-ordinates. 
For the purpose of exhibiting the gravitational displacements, residuals have been 
computed using adopted values for the scale and orientation given above, along vuth 
the calculated corrections for differential refraction and aberration. Tliis has the 
advantage of reducing the number of constants employed in the reduction of the plates, 
and lessens the. possibility of masldng any discordances, though greater irregularities 
necessarily appear Avhen four arbitrary constants instead of six are used in the reduction 
VOL. CGXX.—A. 2 u 
