Introduction 
xi 
1868 
125848 
Oct. 11 
II2?70 
Apr. 29 
82862 
Oct. 16 
57-05 
July 
18 
16 
111 -95 
May 6 
8 i .57 
21 
56.30 
l 9 
•33 
17 
.80 
8 
•27 
25 
55-70 
20 
.18 
24 
110.74 
10 
80.96 
Nov. 2 
54-49 
26 
124.28 
2 7 
.29 
12 
.66 
3 
•34 
28 
123.98 
2 9 
109.99 
14 
•36 
4 
.19 
3 1 
•S 3 
Nov. 3 
.24 
20 
79.46 
13 
52.84 
Aug. 
2 
■ 2 3 
Dec. 19 
102.32 
22 
. 16 
14 
.69 
9 
122.18 
24 
101.57 
2 3 
.01 
19 
51-94 
11 
121.87 
24 
78.86 
22 
•49 
12 
121.72 
27 
• 41 
24 
.18 
1 3 
•57 
1869 
99-46 
3 i 
77.81 
Dec. 3 
49-83 
14 
.42 
Jan. 7 
June 1 
.66 
9 
48.93 
16 
.12 
10 
.01 
9 
76.45 
27 
46.22 
17 
120.97 
14 
98.41 
12 
.00 
18 
.82 
16 
.11 
14 
75-70 
.67 
2 7 
96.46 
16 
.40 
O 
00 
w 
21 
•37 
29 
•15 
July 17 
70.74 
Jan. 19 
42.76 
22 
. 22 
Feb. 1 
95 - 7 ° 
18 
•59 
22 
• 3 i 
2 3 
.07 
2 
•55 
20 
•29 
26 
41.71 
2 5 
119.77 
7 
94.80 
22 
69.98 
28 
• 41 
26 
.62 
13 
93 - 9 ° 
25 
•53 
3 i 
40.96 
28 
■ 3 2 
2 5 
92.09 
Aug. 18 
65.92 
Feb. 7 
39 - 9 ° 
3 1 
118.87 
28 
91.64 
19 
•77 
10 
•45 
Sept. 
2 
•57 
Mar. 1 
•49 
22 
•32 
23 
37 - 5 ° 
5 
.11 
3 
.19 
23 
•17 
26 
•°5 
6 
H7.97 
9 
90.29 
24 
.02 
Mar. 6 
35-84 
8 
.66 
12 
89.84 
26 
64.72 
9 
•39 
10 . 
• 3 6 
16 
.24 
28 
.42 
14 
34.64 
12 
.06 
17 
•°9 
Sept. 11 
62.31 
18 
.04 
14 
116.76 
18 
88 .94 
13 
.01 
24 
33-14 
is 
.61 
21 
.48 
i 7 
61.41 
Apr. 3 
3163 
16 
.46 
22 
•33 
19 
.11 
9 
30.73 
17 
• 3 i 
2 5 
87.88 
20 
60.96 
13 
•13 
21 
ii 5 - 7 i 
28 
•43 
23 
• 5 i 
23 
28.62 
26 
114.96 
Apr. 1 
86.83 
24 
•36 
26 
•17 
28 
• 6 5 
10 
85.48 
28 
59-76 
3 ° 
27-57 
2 9 
• 5 ° 
13 
•03 
30 
.46 
May 5 
26.82 
Oct. 
1 
. 20 
i 5 
84.72 
Oct. 2 
. 16 
13 
25.62 
3 
113.90 
18 
• 2 7 
6 
58.55 
19 
24.71 
5 
.60 
2 3 
83 - 5 2 
8 
•25 
27 
23-51 
9 
.00 
2 5 
. 22 
11 
57.80 
30 
.06 
COMPARISON OF POSITIONS OF SPOTS OBSERVED BY PETERS WITH THOSE OBTAINED BY 
CARRINGTON AND AT KEW 
Carrington’s classic series of observations, entitled “Observations of the Spots on the Sun from November 9, 
1853, to March 24, 1861, Made at Redhill” (published in 1863), overlaps that of Dr. Peters during the period from 
May 23, i860, to March 24, 1861, in which interval observations were made by the two observers on the same day 
in fifty-two instances. Carrington’s telescope had an aperture of 4.5 inches and a focal length of 52 inches. He 
observed transits of the projected image across bars in the focal plane inclined 45 0 to the direction of the diurnal 
motion. 
The Observations made at Kew 1 with the photoheliograph, which in effect form a continuation of the Redhill 
series, were begun on February 7, 1862, and were continued for ten years. They accordingly cover the last eight 
years of Dr. Peters’ work. The interval not included by the English observations was from March 25, 1861, to 
February 6, 1862, although the Kew instrument was being employed in a preliminary way during this time, so that 
the gap might perhaps be fairly bridged without the records of Dr. Peters. The Kew photoheliograph had an aper¬ 
ture of 3.5 inches and a focal length of 50 inches. 
1 Warren de la Rue, Balfour Stewart, and Benjamin Loewy, “Researches on Solar Physics: Heliographic Positions and Areas of Sun-Spots 
Observed with the Kew Photoheliograph During the Years 1862 and .1863. Philosophical Transactions, 159, 1-110, 1868. 
