412 
ME. WAEEEN DE LA EIJE ON THE 
beam compass, in order to obtain a value in arc for the measurements taken in inches 
and decimals of an inch. This accomplished, it was only necessary to measure the 
distance from the moon’s centre or periphery of certain parts of the prominences in 
both totality-pictures, and to compare the results of the measures obtained on one 
picture with those on the other, for the purpose of ascertaining the amount of motion 
of the lunar disk in reference to the several prominences, and to reduce the resulting 
numbers to their value in arc. 
The amount of motion is given in column 14 for those prominences which are visible 
in both photographs. 
Thus, in a direction nearly at right angles to the path of the moon’s centre, the 
apparent motion of the periphery was 1", while at 83° from that point, or 7° from the 
line of motion of the lunar centre, it was 93". 
The motion of the moon’s periphery, in respect of the several prominences situated at 
an angle 0 would be 92"-8 . sin (^—27° 10'), 27° 10' being the position of a line at right 
angles to the motion of the lunar centre, as deduced from the photographic measures 
already given. For the following calculations, the angle 6 was obtained from Plate XY., 
in which the prominences are referred to the sun’s centre. 
Part 
measured. 
Angle S. 
0 i 
Measured 
motion. 
II 
Computed 
motion. 
II 
Measure 
—computation. 
II 
Prominence A 
a 
26 
9 
1 
1-6 
-0-6 
C 
c 
56 
34 
44 
45-6 
-1-6 
C 
c' 
61 
39 
51 
52-5 
-1*5 
E 
e 
67 
4 
65 
59-5 
+5*5 
H 
h'" 
110 
9 
93 
92-1 
+0-9 
P 
r 
346 
14 
60 
60-9 
-0-9 
-fOffi Mean. 
From Table VI. are derived the following numbers : — 
Prominence A 
C 
E 
H 
P 
Part 
measured. 
a 
c 
e' 
7i'" 
r’ 
Angular shift in respect of the moon’s centre 
during totality. 
Measured. 
o 1 
5 32 
4 34 
4 2 
0 52 
3 45 
Calculated. 
O / 
5 21 
4 35 
3 46-5 
0 41-5 
3 56-5 
Measure — computation. 
-fii-o 
- 1-0 
+15-5 
-1-10-5 
-11-5 
+ 4‘9 Mean. 
=1"’4 motion of the moon’s centre in excess of the computed quantity. 
It would be extremely difficult to obtain more comincing proofs that the luminous 
prominences belong to the sun than the foregoing numbers offer ; but I haA'e still one 
more to bring forward. 
* The relative motion of the centres during totality as calculated by Mr. Caebikgtox. 
