DEFLECTION OF LIGHT — DYSON AND OTHERS. 
159 
of the clouds was due to the eclipse itself, as it was noticed that 
the sky usually cleared at sunset. 
It had been intended to complete all the measurements of the 
photographs on the spot; but owing to a strike of the steamship 
company it was necessary to return by the first boat, if we were not 
to be marooned on the island for several months. By the inter- 
vention of the administrator, berths, commandeered by the Portu- 
guese Government, were secured for us on the crowded steamer. We 
left Principe on June 12, and after transshipping at Lisbon reached 
Liverpool on July 14. 
30. The following is a list of the photographs, including the 
comparison photographs kindly taken for us by Mr. F. A. Bellamy 
at Oxford, before the instrument was dismounted. All the eclipse 
photographs are given though only W and X furnished results. Of 
the other series only the exposures actually used in the reductions 
are given. 
List of plates. 
Check Field (R. A. 14h. 12m. 47s., declination +20° 30'). 
Reference. 
Place. 
Date. 
Local sidereal 
time. 
Expo- 
sure. 
Approx. 
Z. D. 
Barom- 
eter. 
Ther- 
mometer. 
h. m. s. 
s. 

in. 
o 
12 55 10 
60 
35 
29.64 
37.0 
13 10 40 
60 
34 
29.83 
35.3 
13 54 55 
60 
31 
29.83 
35.3 
14 9 25 
60 
31 
29.83 
35.3 
13 13 30 
60 
33 
30.45 
29.0 
Plate. 
Oxford. 
...do.... 
...do.... 
...do.... 
...do... 
1919. 
Jan. 16 
17 
17 
17 
23 
Reference. 
Place. 
Date. 
Greenwich 
mean time. 
Expo- 
sure. 
Approx. 
Z. D. 
Barom- 
eter. 
Ther- 
mometer. 
h. TO. s. 
s. 
o 
in. 
o 
12 25 40 
40 
43 
29.45 
76.5 
12 31 20 
40 
45 
29.45 
76.5 
12 37 50 
80 
46 
29.45 
76.5 
12 22 20 
40 
45 
29.45 
76.5 
12 26 20 
40 
46 
29.45 
76.5 
Plate. 
Vl.. 
Wi. 
Principe . . 
...do 
...do 
...do 
...do 
1919. 
May 22 
22 
22 
25 
25 
S.R. 
S.R. 
S.R. 
s.s. 
s.s. 
Eclipse Field (R. A. 4h. 19m. 30s., declination +21° 43'). 
Reference. 
Di. 
G,.. 
Hi. 
I2.. 
Place. 
Date. 
Oxford 
...do 
..do 
...do 
..do 
1919. 
Jan. 16 
22 
22 
22 
Feb. 9 
Local sidereal 
time. 
Expo- 
sure. 
Approx. 
Z. D. 
Barom- 
eter. 
Ther- 
mometer. 
h. m. s. 
s. 
o 
in. 
o 
3 58 1 
6 
30 
29.65 
39.0 
4 4 39 
5 
30 
30.30 
31.0 
4 34 28 
5 
30 
30.30 
31.0 
4 48 46 
10 
31 
30.30 
31.0 
4 45 24 
10 
30 
30.48 
24.5 
Plate. 
