sf
'*/
nf
nf
np
nf
nf
45.689
. 6.474
45.000
22.169
26.649
27-332
Unchanged.
Pos. unchanged.
Pos. unchanged.
Pos. unchanged; Dist. — i".i9.
Unchanged.
'Pos. unchanged.
3-5 '3
I 6.683
. . . 5.090
.. 38.128
75 20
8 24
27 30
II 17
80 15
60 23
26 I
65 30
54 6
76 15
32 26
60 50
82 36
np
*/
np
np,sf
np
.np
nf
np
«/
sp
sp
sp
I
. 3.766
24.581
58.608
44.199
51.840
10.829
Pos. very slightly changed.
Scarcely altered.
, . . 51.022
. .. 30.071
. . 21./J98
..11.352
2 54,906
.. 16.843
••'3H3
. . . 2.716
...6.723
I 0.387
... 3.632
14.205
40.865
59-331
7.869
33-500
20.304
Unchanged.
Changed in Pos. and Dist. ?
Slight change in Pos.
Binary ; mean mot. -f 0° 30' per ann.
Epoch 1825.30.
Pos. changed 4°. 47 ; Dist. unaltered.
Unchanged.
Unchanged.
Single measure.
detailed in the present ^ and preceding communications.
Vol.
for
1826
1826
1826
1826
1826
62
63
Star's Name, &c.
64
64
65
P-X. 159
H.C. 331; A &B
A &C
Nova .
P.X. 179.
H. C. 227
Observer
and Number.
s..
s..
,613
.614
s.
s.
s.
,6i5
.616
.617
10 39
10 39
10 39
10 43
lo 45
Deci.
14 41 s
14 20S
13
44 S
8 25N
1 17S
Position.
78 57
72 26
68 44
88 44
3S 2»
87 47
Quadrant.
sp
tip
np
Distance.
31.651
. 7.262
17.861
26.078
12.510
35-223
Remarks.
1824
1826
1824
1826
1826
42 |54Leonis.
Nova
V. Ill
ir. 78 .
Nova .
H&S 117
S 6i8
H&S 118
S. . . .619
S. . . .620
fo 46
10 47
10 49
10 57
10 58
25 43 N
20 9 S
59 50 N
8 oN
12 28S
8 19
54 16
51 ^6
74 1
73 19
sp
• 7-023
19.101
35.010
. 8.637
32.698
Unchanged.
Distance increased ?
Unchanged.
1826
1826
1824
1826
1824
^1
68
68
44
69
407
1790.386; AandB.
A and C. ,
1790-389
145.68
H.C. 61
145-104
S. . . .621
S. . . .622
H&S 119
S. . . .623
H&S 372
II o
II 3
II 6
11 6
II 7
66 59 N
74 26 N
53 44 N
28 33 N
15 22 S
64 30
26 34
26 16
75 29
5
36
13
«/
np
np
np
nf
np
43431
23.201
12.479
13-144
.4.103
20 d:
1824
1824
1824
1826
1826
1826
45
45
46
331
69
70
1824
1824
1824
1826
1824
1826
1826
1824
1824
1826
1826
1824
1824
1824
1826
1826
1824
1824
1S24
1826
1826
1826
1824
1824
1824
1826
1824
1824
1824
1824
72
73
74
58
58
75
76
60
60
61
76
61
62
63
64
145.26 ....
(pLeonis. . .
I Ursae Maj.
H. C. 498
H. C. 223
201 Bode Camelop.
83 Leonis
T Leonis
57 Urs. Maj
145-70
Nova
1790; 381
88 Leonis
90 Leonis i and 2 .
I and 3 .
Nova
H. C. 64
93 Leonis
Nova
I Virginis i and 2
I and 3
H.C. 385
IV.49
V. 60
65 Urs. Maj. i and 2
I and 3
2 Comae Beren
1790; 376
H.C. 232
Nova
H.C. 354
207 Bode Camel.
H.C. 152
Nova
2 Canum Ven
Struve, 408
145.22
55 Bode Com. Ber.
H&S 120
H&S 121
H&S 122
S. Re-exam.
S. . . .624
S. . , .62s
H&S 123
H&S 124
H&S 125
S....626
H&S 126
S. . . .627
S 628
H&S 127
H&S 128
.629
S. . . .630
H&S 129
H&S 130
H&S 131
.631
S. . . .632
H&S 132
H&S 133
H&S 134
S....633
S....634
S....635
H&S 135
H&S 136
H&S 137
S....636
H&S 138
H&S 139
H&S 140
H&S 141
II 17
II 18
II 19
II 19
II 21
II 21
II 21
II 23
II 25
II 28
II 30
II 38
II 38
II 39
II 39
II 43
II 44
ii 46
II 55
II 56
12 o
12 7
12 8
12 9
12 12
6 8S
2 40 S
32 33 N
o 40S
15 16N
82 2N
4 oN
3 50N
40 20 N
42 21 N
16 26 S
60 40 N
15 22N
17 48 N
22 25N
27 57 N
21 13N
21 2N
9 15N
68 19 N
9 48N
16 26 N
47 29 N
22 28 N
52 55 N
15 48 S
I 15S
54 28 N
82 43 N
6 15S
10 58N
41 40 N
81 6N
2 56S
28 5N
7 37
16 56
II 33
25 28
18 I
79 40
np
sp
sp
sp
nf
7.062
46.256
. 2.809
. 2.442
10.145
. 4.927
Much changed in Pos. and Dist.
Binary.
Epoch 1825.25.
43
61
79 «
79 45
o 21
60 45
O 22
50 14
61 8
36 41
5 34
4 o
86 15
65 3
3 25
53 19
89 4
61 44
75 57
55 26
24 17
31 15
4 26
7 3
7 4
46 19
13 16
18 9
24 37
10 29
50 15
72 58
23 42
np
nf
np»sf
np
sp
sp
np
nf
np
nf
np
np
sp
nf
nf
sp
np
np
sp
nf
np
sp
sp
sp
sp
sp
.. 21.876
. . 29.542
I 35.217
. . . 6.294
.. 13.040
28.959
13.040
14.670
• 4-452
0.753
44.374
... 5.592
I 14.897
I 16.861
11.845
30.382
37-112
. 4.020
2.185
. 3.685
- 8.309
. 7.971
23-673
12.102
3-445
. 9.225
26.580
11-534
15-389
21.017
• 9-453
Pos. changed +6° 11'.
Much increased in Dist.
DifF. of Pos. = 4° 9'.
Scarcely altered.
No change.
Pos. unchanged.
Pos. changed 5° 14'. Dist. diff. 2''.9
Pos. changed — 5°.
Unchanged.
Scarcely altered.
Very little, if at all changed.
Unchanged.
MDCCCXXVi.
A synoptical view of the results afforded by the ohservatiom
165
333
166
77
167
77
167
[68
169
79
70
335
71
334
73
79
74
180
74
75
76
H. C. 230 .... .
Nova
IV. 58 I and z.
.... I and 3.
.... I and 4.
35 Comas Ber,. .
H.C.73
180
[76
77
77
,78
407
li
li
[80
[82
•83
181
■83
li
182
182
■ 84
185
;85
[86
:8s
;86
408
[86
[86
[87
[87
[87
188
[88
star's Name, &c.-
17 Virginis
12 Com. Ber.
Nova
H. C. 385..,
Nova
^Corvi
H. C. 231 ..,
145.118. . . .
24 Com. Ber.
V. 129
Nova . . . . ,
145-38 ....
y Virginis
III. 53
Nova .
Nova
II. 42
P. XII. 221 ..
12 Can. Ven.
Struvk, 430.
212 Bode Camel.
Nova
Nova
9 Virgin, i and 2
...... I and 3
Nova
Nova
54 Virginis
Nova
P. XIII. 25
H. C. 506 .
^ Urs. Maj
426 BoDB Urs. Maj.
V. 128
Nova
iH.C.33s?
Nova
8 1 Virginis . .
0 84 Virginis.
Nova
Nova
Nova . . . .
H. C. 335
Nova . . . .
Nova . . . .
fi Bootis . .
Observer
and Nuiiiber.
H&S 142
S. Re-exam.
H&S 143
S....637
H&S 144
S....638
H&S 145
H&S 146
H&S 147
H&S 148
S....639
S 64.0
H&S 149
S. Re-exam,
H&S 150
S. Re-exam,
H&S 151
S 641
H&S 152
S.. . .642
H&S 153
H&S 154
H&S 155
S....643
H&S 156
H&S 157
H&S 158
H&S 159
H&S 373
S 644
S....645
H&S 160
S....646
S....647
H&S 161
S 648
H&S 162
H&S 163
H&S 164
S 649
H&S 165
S. . . .650
H&S 166
S....651
H&S 167
H&S 374
S....652
S....6S3
S....6S4
H&S 168
S....655
S....656
H&S 169
R. A.
b. m.
12 13
13
18
2
2
2 19
2 20
2 21
2 22
2 25
2 26
2 29
2 29
2 32
2 32
2 36
2 36
2 40
2 40
2 43
2 44
2 44
2 44
2 46
2 47
2 48
2 48
2 48
2 51
2 58
3 I
3 I
3 4
3 5
3 6
3 15
17
22
23
25
3 26
3 27
3 28
3 34
3 36
3 38
3 40
3 41
3 42
3 42
3 46
Decl.
6 19N
26 51 N
18 58S
45 50 N
26 54N
15 30 S
2 20N
75 46 N
19 22N
3 23S
4 22 S
12 1 S
o 27S
2 54S
15 20N
4 48N
14 58N
20 9N
22 14N
16 oN
4S
54 S
29 N
18N
iN
84 24 N
15 18N
I 35N
4 34S
16 25 N
I 43 S
7 5»S
19 oN
10 24S
3 38N
55 52N
60 53 N
II 46S
«2 33S
27 loN
25 35 S
6 57 S
4 27N
9 40S
19 18N
25 N
S2N
35 N
12N
19N
Position.
69 36
66 15
78 47
66 54
72 52
19 ^3
56 27
19 39
6j 10
2 7
15 22
5 50
29 26
31 27
13 24
6
78
56 35
75 38
53 50
67 49
59 23
4 o
38 18
79 53
60 19
73 43
43 2
15 »5
57 o
81 9
84 48
77 8
24 3
72 46
56 9
56 17
25 22
28 21
13 39
57 46
21 2
11 13
59 10
24 51
77 30
47 16
40 9
56 50
82 55
32 13
70 25
14 o
6i 50
29 27
Quadrant.
np
np
sp
.sp
np
np
np
sp
nf
sp
np
sp
sp, nf
np
np
np
sp
nf
np
np
np
sp
nf
nf, sp
sf
nf
nf
sp
nf
sp
*/
sp
sp
nf
sp
Distance.
20.937
19.910
5.950
»-635
11.079
24.436
24.005
49745
. 5.865
20.647
50-555
10.197
.6.881
. 6.077
• 3-794
. 3.263
16.766
33-359
10.109
54.421
9.666
31.644
29.494
• 7-995
23.509
6.758
29.170
19.764
.4.136
22.069
27.159
. 8,098
. 8.301
. 4.090
43 '29
. 6.774
28.970
44.847
28.465
14.455
1.495
47.720
45-524
. 9.613
10.350
. 4.020
.3.918
53.869
30.517
10.844
. 5.664
35-054
26.033
6.203
Pos. changed + 1 1^
Epoch 1825.30.
Pos. unchanged.
15', arising from
[proper motion,
Unchanged.
Unchanged.
Epoch 1825.28.
Binary; mean mot. — o°,667.
Epoch 1825.32.
Unchanged.
Unchanged.
Pos. changed ■\- 7° 55'.
Unchanged.
Pos. changed -f 7°5o'.
Distance increased.
Unchanged.
Distance increased.
Pos. changed — 6° 4'.
Binary? mean mot. rr — o°.288.
il
detailed in the present, and preceding communications.
Vol.
for
1824
1826
1826
1824
1824
1826
1826
1826
1826
1824
189
88
i89
[90
[90
star's Name, &c.
H. C. 162
Nova . . . .
H.C. 335.
T Virginis
145.82 ...
observer
and Number.
H&S 170
S....6S7
S 658
H&S 171
H&S 172
R. A.
h. m.
'3 46
13 5»
13 52
13 54
Decl.
o /
33 43 N
7 12S
26 41 N
2 26N
20 17N
Position.
58 28
38 i6
28 52
19 57
71 43
Quadrant.
np
sp
np
Distance.
.... 7.780
. . . . 2.699
5.016
. I 19.290
. .. 21.392
189
[90
[90
191
191
H.C.233.
Nova . . . ,
Nova . . . ,
Nova . . . .
145.98...
S....659
S 660
S....661
S....662
H&S 173
»3 56
14 o
14 I
H 3
»4 5
17 12S
22 3N
2 30S
29 35 N
6 14N
79 *7
69 43
62 51
17 32
79 20
nf
«/
sp
32.031
. 4.888
• 7-937
13.801
. 6.049
1824
1824
1824
1824
1824 3
[91
'93
[94
'95
[96
1824
1824
1824
1824
1824
[97
198
'99
200
201
1824
1824
1826
1826
1824
1824
1826
1824
1824
1824
1826
1824
202
204
336
191
208
208
33^
213
216
409
192
215
1824
1826
1824
1826
1824
1824
1824
216
192
217
193
218
K Bootis . . .
» Bootis
P. XIV. 62
H.C. 334 .
H. C. 470 .
H&S 174
H&S 175
H&S 176
H&S 177
H&S 178
H
H
7
10
»3
14 14
14 15
X Turdi Sol.
H.C. 165 ..
IT Bootis. . . ,
^ Bootis . . . .
II. 82
73 Hydrae
{ Bootis . .
Nova . .
a Librae
I Bootis
39 Bootis
H5-28
1 8 Librae
Nova
346 Bode Bootis.
145-63 •....
Nova
45 37
33 Bode Urs. Min.
44 Bootis
H&S 179
H&S 180
H&S 181
H&S 182
H&S 183
H&S 184
H&S 185
S, Re-exam,
S....663
H&S 186
H&S 187
S. Re-exam.
H&S 188
H&S 190
H&S 375
S....664
H&S 189
H&S191
S....665
H&S 192
S....666
H&S 193
14 15
14 22
H 32
»4 33
H 36
H 36
14 37
14 40
14 41
H 43
14 44
1448
14 49
H 53
H 55
H 55
H 55
14 56
14 56
14 58
52
52
6
9
12
39N
12N
56 S
16N
3N
3» 15
56 36
77 6
83 24
65 17
19 8S
29 6N
17 12N
14 31 N
8 27N
25 49
7 36
7 53
36 58
4 27
24 40 S
27 51 N
23
30 S
'5
15S
19
51N
46 40
52 59
54 26
50 53
44 33
70 54
67 o
27 N
35 S
24 S
29 N
2N
54 33 N
17 13S
6 12N
75 36 N
48 21 N
44 55
o 9
54 8
84 2
68 S3
sp
np
sp
np
^•136
38.047
. 5.880
. 7.185
1 o. 1 92
Pos. slightly changed.
Very little changed.
np
sp
35.121
25.781
. 6.889
. 1.683
• 7.335
np
np
sp
np
np
np
. . . 9.995
... 3.931
••• 3.356
. . 56.696
3 50-853
. . . 8.696
. . . 7.776
73 »o
I 51
j6 30
52 3
40 53
np
nf
sp
-L
np
^f
np
nf
sp
. 4.626
10.833
26.614
25.837
36.544
. . . 40.845
. . 25.270
. . 10.749
2 53.180
...2.277
Unchanged.
Unchanged in Position.
Changed 8° 25' in Pos.
Binary; mean mot. +o°.4378.
Epoch 1825.34.
Greatly changed in Pos. and Dist.
Epoch 1825.37.
Probably changed in Pos. ; our observa
[tions rather dubiou
Unchanged.
219
410
1826
1824
1826
193
220
194
H.C. 472
24 Librae 1 and 2.
I and 3 ,
Nova
97 Bode Librae...
Nova
H&S 194
H&S 376
S....667
H&S 195
S 658
14 59
15 2
•5 3
15 4
^S 4
55N
6S
60 50
21 39
4 55 S
17 45 S
39 38N
21 39
65 39
50 58
63 50
sp
*/
np
sf
np
• 4-777
50.629
31.181
49037
10.740
1824
1824
1824
1826
1824
221
221
222
'95
222
V. 125...
14562 ...
H. C. 289.
Nova . . . .
^ Bootis . .
H&S 196
H&S 197
H&S 198
S....669
H&S 199
»5 5
15 8
28 36 N
19 56N
39 22N
15 5N
34 oN
43 17
80 51
13 29
73 8
10 31
sp
nf
np
nf
nf
32.553
35.842
31239
. 6.057
45-333
1824
1826
1824
1S24
1824
1826
223
195
224
225
226
339
H.C. 470...
5 Serpentis. .
« Coron. Bor.
H.C. 288...
17
H&S 200
S. . . .670
H&S 201
H&S 202
H&S 203
S. Re-exam.
15 10
15 lO
15 16
15 18
15 18
II 7N
2 28N
30 57 N
8 41 S
37 59 N
84 20
50 57
64 3
44 39
63 42
^3 32
nf
nf
*/
np
np
13.268
10.698
• 1-577
51.760
. 1.652
. 1.421
> I, 2 and 3 are precisely in a line.
Slightly changed in Pos.
Scarcely changed.
Binary; mean mot. — 0**.578j.
Epoch 1825.46.
A synoptical view of the results afforded by the observations
Vol.
for
229
196
197
197
231
341
411
232
198
234
1824
1824
1824
1824
1824
1826
1824
1824
Star's Name, &c.
HA Bootis . . .
Nova
Nova
Nova
S Serpentis .
Struve, 489
178 Bode Librae. . .
Nova
H. C. 469
^ Coron. Bor
236 145.32.
237
238
239
240
Observer
and Number.
H & S . 204
S 671
S 672
S 673
H&S.205
S. Re-exam.
H&S.
H&S.
S
H&S.
H&S.
377
206
674
207
208
w' Urs. Min.
II. 85
III. 103..
H.C. 343.
198
199
240
241
1824
1826
1826
243
343
345
346
199
Nova J A and B . .
.. AandC...
V. 126
II. 21 ; I and 2..
I and 3..
I Scorpii
AandB.
AandC.
B andC.
Coronae Bor. . . .
H&S. 209
H&S. 210
H&S. 211
H&S. 212
H&S. 213
R. A.
h. m.
15 18
15 18
15 22
15 23
15 26
15 27
IS 30
15 32
15 33
15 33
15 40
15 40
IS 47
15 48
IS 49
Decl.
38 IN
10 20 S
19 35 S
23 52 S
11 9N
Position.
Quadrant.
27 20 N
8 iiS
36 54N
10 33 S
37 iiN
S 675
H&S. 214
H&S. 215
H&S. 216
S. Re-exam.
S 676
IS 51
15 52
IS 54
15 54
IS 54
36 59 N
81 2N
I 39S
3 5
6N
19 24S
22 16N
17 S4N
10 56 S
10 52S
33 52N
81 51
42 44
13 14
27 24
70 37
69 49
30 20
82 46
5 o
38 5
30 57
S3 43
6 43
55 »7
S3 4
52 10
np
np,sf
sp
sp
sp
sp
sp
nf
np
61 46
33 34
53 25
10 57
78 39
11 37
81 54
9 3
»7 30
35 6
np
nf
np
np
np
Distance.
I 48.539
•••9-573
.. 11.468
...9.178
... 3.053
...3.268
.5.941
11.862
15.648
27.066
.7.168
sp
sp
sp
*/
np
nf
31-517
31.102
. 6.882
10.665
19.890
Unchanged.
Binary ; mean mot. — o°.']z6.
Epochs 1825.46 and 1825.42.
Changed + 5° 6' in Position.
Changed — 9° 8' in Pos. and nearly 3" in
Distance.
. . . 5.086
I 1-533
• • 34.923
. . 10,601
4 41.533
. . . 6.769
...1.358
. . . 6.961
I 19.196
Binary ? Mean mot. — o°.256.
} Epoch 1825.50. Not the slightest alter-
ation in the Pos. or Dist. of A. and B.
Sir W. H's Pos. = 54° 27' sf Mr. H. sup-
poses his micrometer was erroneously
read off.
1824
1824
1824
1824
1824
1826
244
245
246
247
247
347
jS Scorpii . .
H.C. 159.
x Herculis.
Scorpii. . .
49 Serpent.
1824
1826
1824
248
348
350
252
0- Coron. Bor.
1824
1824
1824
254
255
256
1824
1824
1826
1826
1824
1824
1824
1824
1824
1824
257
259
201
202
260
H&S. 217
H&S. 218
H&S. 219
H&S. 220
H&S. 221
S. Re-exam.
^Aand B
A andC
V Coron. Bor. 1 and 2
I and 3
20 o- Scorpii
V.134
V. 124
H&S. 222
S. Re -exam,
H&S. 223
H&S. 224
H & S.225
H&S. 226
y Herculis . . .
g 5 Ophiuchi.
II. 88
23 Herculis. .
H &S.227
H&S. 228
s (>n
S 678
H.C. 78.
H&S. 229
IS
15
16
16
16
16 8
16 10
16 10
16 10
16 10
16 14
16 15
16 15
16 16
16 18
18S
49 N
32N
58 S
iN
63 30
58 44
80 25
68 12
41 57
48 10
^f
np
nf
np
np,sf
np
34 20 N
29 36 N
25 9 S
19 36 S
19 40 s
19 35N
23 iS
14 15 N
32 45 N
37 27 N
18 27
12 29
0 39
65 33
35 9
1 II
64 58
69 29
26 14
87 30
48 23
69 38
j6 21
nf
ff
sf
nf
nf
7ip
np
nf
sp
nf
np
nf
np
13.650
31.935
31.169
40.817
.4.215
.3.501
Unchanged.
Distance diminished 8".7i 1.
Unchanged.
Binary; mean mot. + o°.5io.
Epoch 1825.41.
• 1-455
. 1.480
42.175
28.694
6.420
20.595
47.120
13.280
Binary; mean mot. -f 2.13, much
lerated and Dist. diminished.
Epochs 1825.44 and 1825.49
Epoch 1825.53.
Unchanged in Distance.
Slightly changed.
acce-
•38-325
. . 4.065
. . 6.770
. 36.844
. 10.155
No material change.
Sir W. H's. Pos. zz 54° 6' sp ; it cannot be
the same star.
261
261
262
263
263
III. 102
71 Bode Hercul.
11. 23 ,
H, C. 228
36 Hercul
H&S. 230
H& S.23 1
H&S. 232
H&S. 233
H& S.234
16 21
16 21
16 23
16 23
16 32
iN
47 N
51N
42 N
33N
71 26
19 12
51 7
17 29
39 37
np
nf
. . . 14-833
....3-236
. . . . 7.649
...59.544
.1 8.839
Probably changed in Pos.
detailed in tJw present, and preceding communications.
Vol.
for
1824
1826
1824
1824
1826
1824
1826
1824
1826
1824
Star's Name, &c.
265
20Z
264
1826
1826
1824
1824
1824
1826
267
267
203
268
203
412
17 Dracon
Nova
V. 127; I and 2...
I and 3 . . .
f Herculis
Observer and
Number.
H.C. 369.
Nova
1826
1824
206
1826
1824
1826
1824
1824
1826
1824
1826
1826
1824
207
269
269
271
352
43 Herculis.
46 Herculis.
19 Ophiuchi
208
272
1826
1826
1826
1824
1824 3
353
354
355
274
208
275
Nova ; A and B . . .
A and C...
A and D . . .
Nova
P. XVI. 236
H.C. 510
2 1 /* Draconis ,
H&S.236
S .679
H&S.235
R. A.
H & S.237
S. Re-exam.
H&S238
S 680
H&S 239
S 681
H&S 378
h. m.
16 32
16 32
16 34
Decl.
16
35
^6 35
16 35
16 37
16 38
16 38
1824
1826
1824
1824
1826
276
364
277
210
210
277
Nova
36 Ophiuchi I and 2
I and 3
A and B..
A andC.
B andC.
« Herculis
38 Ophiuchi
^g 0 Ophiuchi. . . .
S 682 16
S....683
H&S 240
H&S 241
H&S 242
S. Re-exam.
39
53 17 N
23 23 N
6 57N
31 56N
Position.
24 oN
13 58N
8 55N
28 42N
2 24N
25
I
21
74
26
5
o
10
Qualrant.
Distance.
21 27
65 36
39 9
73 51
10 ±
S....684
H&S 243
S. Re-
exam.
H&S 244
S....685
H&S 245
30 18N
36 15 N
19 15S
47 36 N
54 43 N
Herculis H&S 246
S. Re-exam,
» Serp. Ophiuch | H&S 247
Nova
70 Herculis
p Herculis .
211 iNova
211 Nova
2 1 2 Nova
278
279
280
1826
1826
1826
1824
1826
1824
1824
1824
>82+|3
1826 I
213
281
283
214
53 Ophiuchi
v Draconis . .
254 Bode Oph. i 8c 2
1 and 3
2 and 3
III. 104. A and B.. .
A and C .
61 Ophiuchi
H. C. 348
Nova
S 686
S....687
H&S 248
S....688
S....689
S — .690
H&S 249
H&S 250
17
H&S
30 37N
26 18 S
14 36N
26 25 s
24 5 S
59 42
50 27
76 15
69 30
42 44
6 3
61 39
61 2
np
np
np
sp
...4.512
• • 17.034
• • 54307
I 30.275
Single.
Single.
10'
. 6.755
13.929
20.094
• 5-391
or 15"
89 10
42 41
19 5
41 32
16 1
17 41
29 33
60 50
85 47
nf
sp
np
sp,nf
sp,nf
Remarks.
Unchanged.
1825.57.
No certainty in Pes. j but increased i
[Distanc(
251
214
215
216
284
216
285
286
412
287
217
i^ Herculis. . . .
295 Bode Oph.
Nova
■vj/ Draconis . , .
Nova
S .... 69 1
H&S 25 2
H&S 253
S. . . .692
25 3N
12 39S
28 57 N
24 41 N
37 19N
37 8N
39 25 N
35 5N
9 43N
55 19N
82 10
83 33
S9 13
85 31
33 26
37 53
sp,nf
np
sp
np
np
*/
np
np
.. 14.761
I 4.299
1 min. ±
...7.158
. . . 5.641
1 55.126
. . . 3.907
• • • 4-330
np
■ • 24.499
..5.546
Distance
. . 5.200
; 15.252
t 13.689
..5.286
•• 7.137
. 12.512
Binary; mean mot. — o°.5792.
Epochs 1825.52 and 1825.47.
17 30 2 8N
17 32
17 36
17 36
17 38
S. . . .693
S . . . . 694
S 695
H&S 254
S....696
6y Ophiuchi
H.C. 168 ..
H5-40
95 Herculis.
II. 90 ,
H&S 255
H&S 256
H&S 379
H&S257
S....697
^7 39
'7 43
17 43
^7 45
17 51
17 52
17 52
17 52
'7 54
'7 54
24 30 N
2 41 N
13 14S
31 14N
76 13
71 39
39 25
78 41
42 23
58 7
68 37
27 23
81 2
71 50
3 33
66 48
65 33
sp
sp
np, sf
. . . 28.869
. . . 26.694
..50.213
..54.982
3 38.339
. . . 4.463
Inaccurate from erroneous micrometric
Epochs 1824.86 and 1825.17. [readin
Epoch 1825,27.
Epoch 1825.53,
Unchanged.
Pos. unaltered ; Dist. increased 3", if tht
Unchanged in Pos. [same star,
Altered + 9° 42' in Pos. and— 5*.349 j
Epoch 1825.50. [Dis
Pos. changed 7° 32'; Dist. + i".494.
27 50 N
1 loN
25 19 N
72 14 N
6 51 S
2 57N
30 5N
22 58 S
21 36 N
26 33 N
29 H
32 6
54 30
75 14
77 45
53 4
*/
8 53
np
61 45
sp
8 8
nf
71 46
^f
np
nf
nf
nf
*/
sp
np
sp
sp
*/
nf
np
• - 33.348
1 29.272
. . 10.799
. . 41.662
1 2.242
51.213
1 8 . 090
54-310
17.214
28.267
20.520
15.869
. 5.029
Unchanged in Pos.
Unchanged in Pos.
29.297
22.681
. 6.768
31777
. 8.396
Change in Pos. -f 2^46' and + 2".88i in
' [Dist.
Unchanged.
Probably unchanged.
55.228
20.181
10.952
. 6.623
• • 7.503
Perhaps slight change in Pos.
MDCCCXXVI.
IV
A synoptical view of the results afforded hy the observations
Vol.
for
1826
1824
1826
1826
1824
1824
1826
1824
1824
1824
I 217
3 288
I 365
I 218
292
3I293
star's Name, &c.
Nova
70 p Ophiuchi
1824 3
1824 3
1824 3
1824 3
1826 I
1824
1826
219
294
296
296
297
S 698
H&S258
S. Re-exam.
Nova S....699
H.C.362 H&S2S9
HI. 56 H&S260
Observer
and Number.
U. A.
Decl.
h. m.
«7 54
17 56
17 56
i7 57
17 57
Nova ._.
73 ? Ophiuchi
100 Herculis..
Nova
Struve, 569..
1826
1824
298
299
299
219
3 1301
1I371
I. 86
H. C. 298
40 Ceph. or Drac.
H.C.474
59 rf Serpent
S 700
H&S261
H&S262
H&S263
H&S264
I 220
1826
i8z6
1826
1824
1824
1824
,1826
1826
1824
1824
1824
303
H&S265
H&S266
H&S267
S 701
H&S268
S. Re-exam
18
18
18
18
18
22 30 S
2 33N
25 23 N
64 9 N
12 oN
Position. Quadrant.
Nova ....
39 Dracon.
372
373
220
305
305
1824
1824
1824
1826
1824
1826
1824
1826
1824
1824
1824
307
374
221
309
310
310
3'i
3^3
3H
375
315
221
I and 2 .
I and 3.
I and 2 .
I and 3 .
Nova . . . .
H. C. 300
H. C. 294
S....702
H&S269
18 12
18 12
18 13
18 15
18 18
16 43 S
3 57 N
26 5N
18 49 S
18 38 S
47 27
64 48
58 3
53 17
15 27
12 21
S. Re-exam,
S....703
H&S270
H&S271
18 20
18 21
18 25
18 30
18 30
25 28 N
15 10 S
71 s8N
6 41 S
o 5N
84 38
12 23
87 35
77 52
37 22
tip
«/
sp .
np
sp
Remarks.
«Lyr£ H&S272
S. Re-exam.
S....704
H&S273
H&S274
H&S275
H.C. 87 .
IV. 94...
H. C. 296
5 Aquilae .
4» • Lyrx
inter i and 5 Lyrae
5 L> rse
1^ Lyrae.
Nova . .
1824 3
1826 I
1826 I
1826 I
1824
317
222
317
318
319
H&S276
H&S277
H&S278
S. Re-exam
H&S279
S....70S
18 31
18 32
18 36
18 36
i8 37
19 13N
58 42 N
32 8N
52 13N
41 7N
82 48
5» 37
34 56
71 o
48 5
48 34
np
sp
nf,sp
nf
H.C. 170 .
/ Lyras . . . .
(3 Lyrae
H.C. 19? .
9 Serpentis ,
1824
1826
1826
1824
1826
320
223
224
225
321
322
226
226
323
227
0 Draconis . . . .
1 1 Aquilae . . . .
11.93
1.58
P. XVIIL 274
1826
1824
1826
1824
1824
228
324
229
325
325
H&S280
S 706
H&S281
H&S282
H&S283
18 38
18 38
18 38
18 38
18 39
38 37 N
9 33N
34 32 N
10 39 S
I 9S
76 51
86 5
68 5
84 40
68 36
66 9
4 34
70 15
np
sp
sp
sp
np
np
ip .
42 7
43 30
I 4
5 51
66 18
32 42
sp, nf
nf
nf
nf
sp .
np
np
39 27 N
39 27 N
39 27 N
37 25 N
34 22 N
18 42
18 42
18 43
18 48
18 48
H&S284
S....707
S 708
S....709
H&S285
15 Aquilse.
Nova
Nova . . . .
IIL 109 . .
1-59
233 Bode Dracon.
H. C. 19?
Nova
Prec. VI Lyrse I H &S 289
6 Bode Cygni H&S290
H&S286
S 710
S 711
H&S287
S 712
18 49
18 51
18 52
18 52
18 54
10 47 N
32 37 N
33 loN
33 46 N
3 58N
64 7
50 ±
69 56
69 II
59 51
68 12
18 56
18 57
18 57
18 58
18 58
59 loN
13 23N
14 41 N
36 iiN
o 58S
85 28
33 58
60 I
80 15
14 26
*/
nf
np
nf
np> */
np, s
4 »7S
16 33 S
27 4S
6 53N
35 32N
S....713
H&S 288
S....714
79 "
29 28
18 19
20 21
58 49
sp
np
np
sp
np
np
sf
30.922
. 4.266
,.4.765
■ 18.744
. 21.093
. . 6.748
Binary ; mean mot. — 6°. 8 11 ; not uniform
Epoch 1825 56.
Scarcely altered.
28.969
. 1.989
14.281
54-302
16.419
Distance increased.
. 4.587
14.091
21.362
. 6.761
.4.151
. 4.465
...6.288
...3.599
I 30.201
...3-593
1 28.939
. . . 6.433
. . 26.226
. . . 6.000
Unchanged.
Binary ?
Epoch 1825.54.
Binary? mean mot. —o°.205.
J Epoch 1825.55.
42.108
41.563
57-657
24.630
. 5.306
, 14.468
Changed in Pos. and Dist. by proper mot«,
Epoch 1825.56.
, . 4.010
.53 ±
. . 3.801
. . 3.340
. 44.240
. . 4.492
Binary ? mean mot. — o°.i9.
Binary ; mean mot. — o°.325.
Epoch 1825.53.
. 4.794
59.840
45-778
46.035
21.679
Change of Pos. = -{-5° 21'.
29-949
19.658
. 6.677
.5.478
, 26.019
No material change.
Unchanged.
Pos. changed 7° 21'; ann. mot. -{- o .173.
18 59
19 2
19 2
19 6
19 7
75 33N
34 18N
34 28 N
38 44N
49 31 N
detailed in the present, and preceding communications.
Vol.
for
1824
1826
1826
1824
1824
Star's Name, &c.
Observer
and Number.
R. A.
1826
1824
1824
1824
1824
326
229
230
328
231
329
330
352
Lyras . ,
Nova . . ,
Nova . . .
fl Lyrae . .
H.C. 90.
1826
1826
1826
1826
1826
1826
1824
1826
1824
1824
}24
231
232
233
233
234
235
28 Aquilae.
H. C. 1 1 1 .
111.57....
II. 69
$ Cygni...
H&S291
S....715
S....716
H&S292
H&S293
S....7,7
H&S 294
H&S295
H&S 296
H&S 297
1824
1824
1826
1824
1826
1826
1824
1826
1824
1826
1824
1824
334
236
335
336
336
n. 99
Nova A and B.
AaiidC.
»3
Sagitta:
H.C. 116
b.
19
19
»9
^9
Decl.
19 II
19 18
19 19
19 21
19 24
S.
S.,
..718
..719
s.
S.
S.
.720
,721
722
19 25
19 25
38 5IN
16 I5S
16 I4S
37 49 N
5 16N
Quadrant.
12 iN
9 54S
20 46 N
36 loN
27 35 N
5 58
74 33
70 51
17 52
87 46
85 6
35 49
63 26
23 16
35 15
nf
«/
sp
np
Distance.
29.336
.9.176
. 6.286
41.665
31.420
Remarks.
27 54 N
36 21 N
337
338
236
339
376
237
151 Bode Aquilag.
f-9i
1 6 Cygni
Struve, 634
Nova I and z ....
1 and 3
339
238
340
377
340
342
1826
1826
1824
1824
1824
1824
1826
1826
1826
1824
Struve, 635
Struve, 636 i and 2.
I and3.
Nova
^ Cygni ,
H&S 298
S 723
H&S 299
H&S 3C0
H&S 301
H&S 302
H&S 303
V. 137.
X Cygni..
Nova . . . .
w Aquilas.
^ Sagittae .
» Aquilx.
238 II. 95.
239 III. 112.
343 57 Aquilae.
344 Struve, 647.
345 {1 Draconis.
S....724
H&S 304
S. Re-exam,
S....725
19 27
19 29
19 29
19 34
19 36
19 37
19 38
19 38
10 33 S
16 4N
17 19S
19 38
'9 38
H&S 305
S 726
H&S 306
S. Re-exam.
H&S 307
H&S 308
'9 39
^9 39
'9 39
346 4/ Cygni
240 JNova ; A and B
.... A and C
"/xSagittffi
Nova
I. 96 I and 2
.... 1 and 3
S....727
S....728
H&S 309
H&S 310
H&S 311
241
241
348
1824
349
1824
1824
1826
1826
1826
1826
1826
1826
1824 3
351
352
243
243
244
244
245
246
247
353
H.
Nova
Nova
Nova
Nova
C. 16 J I and 2.
I and 3 .
H&S 312
S 729
19 40
19 40
19 41
19 41
19 42
8 43 S
10 21 N
50 6 N
33 14N
33 HN
^5 38
33 27
24 46
46 3
857
32 45
np,sf
ff, sp
59.280
11.314
. 6.938
• 7-430
34-383
n 52 N
35 39N
20 30 N
44 42 N
34 37 N
56 34
6 27
45 13
56 15
15 56
57 35
»9 43
19 43
»9 45
19 45
19 49
20 N
27 N
22 N
18 43 N
8 24N
S 730
S 731
H&S 313
H&S 314
II. 70
V. 136
9Sagittae A and B...
AandC...
Nova
II. 96 .*.'
H&S 315
H&S 316
S 732
^""133
19 51
19 52
19 52
'9 53
19 56
o 2N
43 55 N
8 42S
19 53N
69 48 N
68 30
36 52
1 '
? 34
Single.
Single.
60 49
nf
nf
np
nf
sp
6.840
. . . . 6.295
. . . 53.228
4.488
.1 31.913
. . . 10.669
Sir W. H. has no measures of this star.
Changed + 4° 50' in Pos. ; Dist. unaltered
Changed + 5° 56' in Pos.
Unchanged.
np
np,sf
np
nf
37.112
• 3-994
37-504
25.871
16 42
63 30
45 27
33 27
44 32
55 48
nf
sp
sp
nf
51 58N
35 3N
S....734
S....735
S....736
S....737
H&S 317
20
20
20
20
17 7N
46 5 N
35 32 N
26 42
70 23
81 8
58 30
8c 21
35 18 N
88 o
25 47
34 12
74 10
63 24
86 52
59 29
sp
np
np
.2
11.936
»5-i33
19.831
. 5.122
38.745
Probably unchanged.
Probably annual motion = + 0^.148.
Unchanged.
Probably a slow change of Pos.
Probably unchanged.
25-503
33.444
. 1.957
1825.
No material change.
np
*/
np,sf
np
Probably unchanged.
have been 35°.27' sf (S.)
Micrometer read off incorrectly; should
1.549 [Epoch 1825.61. Unchanged.
8.818 JBinary? mean motion.
2 33-375
• 5.587
10.415
36.158
42.427
. 2.590
sp
np
sp
nf
sp, nf
*/
np
Common proper motion.
No sensible variation.
Unchanged.
Probably unchanged.
Pos. unchanged.
20
20
20
20
20
35 >7N
35 7 N
20 36 N
34 57 N
16 16N
o 40S
20 22 N
20 25 N
o 19N
30 58
61 48
33 26
54 3
71 o
32 48
75 24
07 43
57 58
43 II
39 24
61 48
np
nf
sp
np
np
np
nf
sp
np
sp
sp
....4.321
....4.318
.4 2.884
•I 55-931
5.992
* ' * '41.335 \ Hardly changed in Pos.
10.793
36.523
20.164
9-479
.4.518
• 5-355
. . . . 6.605
. . 54.670
... u 777
I 10.088
I 41.069
... 4,100 j Perhaps a slow change in Pos.
Probably unchanged.
Unchanged.
Distance unchanged.
Posit, not given by
[Sir W. H.
XVI
A synoptical view of the results afforded by the observations
Vol.
for
1826
1826
1826
1824
1826
1824
1826
1824
1826
1826
247
248
248
354
I249
star's Name, &c.
Observer and
Number.
1826
H.C.297
Nova
P.XX.43,44
H.C. 182
Nova ; A and B . . .
AandC.
355
250
413
251
251
« Capricorni
0* Cygni. . . .
a- Capricorni
32 Cygni...
Nova
S....738
S....739
S....740
H&S318
S....74>
R. A.
Decl.
Position.
Quadrant.
b.
20
20
20
20
I20
33 7N
6 33S
6 4N
4 2 S
21 45 N
H&S 319
S 742
H&S 380
S....743
S....744
1826
1824
1826
1824 3
1826
1826
1826
1824
252
253
355
258
259
356
379
^ Capricorni A and B
A and C
H.C. 240
1.95
Nova; A and B .
BandC.
Cephei
1824
1826
1826
1826
1826
254
255
358
359
•745
20 8
20 8
20 9
20 10
20 II
S....746 ,
H&S 320 I
S....747
H&S 321
S. Re-exam.
20 II
20 12
20 14
20 14
20 15
13 3 S
46 12N
19 40 S
47 loN
12 28N
H.C. 176
P. XX. 140
p Capricorni. VI. 29 . .
11.51.-
361 0 12 Capricorni
255 Nova
S....748
S....749
H&S 322
H&S 323
H&S 324 |20 20
S 750 120 22
15 21 S
45 4N
54 48 N
15 50N
77 loN
22 15
39 26
77 II
36 33
86 13
60 12
21 26
83 53
86 27
85 34
52 51
20 i»
20 18
20 19
20 20
I 1256
I 256
I 257
1824I 3I362
1826
1826
1826
1826
1826
1826
15 Bode Delphin.. . S 751
H.C. 537 S....752
37 Bode Cephei S 753
H.C. 109 \ll8cS 325
1824
1826
1826
1826
1824
I 258
I 259
I 260
I 261
I 261
210 Bode Cygni.
u^ Cygni
Nova
H.C. 114
IV. 92; AandB.
20 22
20 22
20 22
20 23
754 20 23
13 44 S
2 42 S
18 24S
18 24S
19 loS
25 48 N
2 54
43 40
43 28
69 39
61 40
17 ±
38 4
36 24
sp, nf
sp
%
Distance.
np
np
. 41.862
. 25.116
.43.893
. . 14.491
. . . 6.439
••57-325
Remarks.
12.999
46-393
53704
28.496
28.383
Pos.changed8°53'.
23 25
80 35
60 45
87 »7
30 17
54 >3
sp
np
S....755
S....756
S....757
S....758
S....759
262 A and C.
20 25
20 26
20 26
20 27
20 28
10 45 N
18 48N
56 3N
10 35N
25 53N
13 35
18 38
29 38
14 22
31 H
sp
*/
sp
np
3 23.715
3 46716
...8.915
... 3.980
- • 30.745
....13 ±
8.138
\ No measures given by Sir W. H.
Each by estimation.
Distance increased 3''.
. 7.871 Epoch 1825.67.
. . 23 803
.. 59.872
3 58.021
... 4.026
, . . 22.060
. I 6.711
48 37 N
48 37 N
27 31 N
13 21 S
14 8N
1826
362
262
263
263
3 363
Nova '
H. C. 106 ,
Nova
52 Cygni
7 Delphini 1 and 2. . H & S 327
I and 3 .
H&S 326 20 32
S 760 20 34
S....761
S 762
20 37
20 37
20 38
38 5N
12 6N
23 17N
30 4N
15 29N
8 49
49 I
31 33
73 49
19 58
52 55
np
sp
np
np
np
np
sp
sp
14.689
45-377
26.446
15.484
25.674
Pos. changed 3° 53' ; Dist. increased 2".6.
1.387
55.791
. 4.468
10.256
25.083
• 54-299
3 1I264 iH.C. 177 1 S.
I1826 I 264 ir. 66 S.
1826 I 266 X Cygni S.
1826 I J266 Nova S.
1826 I I267 jll. 100. 1 s.
•763
.764
.765
.766
.767
20 38
20 38
20 40
20 42
20 43
18 51 S
15 14N
35 50N
88 43
3 o
61 56
32 40
3 43
78 35
25 6
84 59
14 29
np
nfysp
np
«/
np
Unchanged.
• 9-478
.9.194
. 2.049 I
. 7.202 [Unchanged.
12.317
.2 20.857
5 46 N 69 31
51 17NI 15 24
np
np
^f
np
nf
I1826I1I268 P. XX. 355 L?;-c"^ Q r ^^
I1824 3I364 UEquulei H&S 328 20 50
1826 I I268 Nova ._.... S. .. .769 I20 50
1826 I 269 280 Bode Cygni S.
I18261 I 270 Nova ' S.
6 40N
3 36N
. . , . 15 47N
770 20 53 49 46 N
771 |20 55 1 6 30S
54 44
10 39
14 2
57 9
78 20
sp
nf
sp
16.749
. 4.979
25.590
• 3-998
. 4 409
Change of Pos. 6° 17'.
Unchanged.
Unchanged.
40.598
12.374
14.987
2.449
• 3.227
Pos. changed — 10^ 45*.
I1826I1 1271 jNova 1 S..^^772 20 56
1826 1 272 Struve, 704 S 773 20 57
18243 365 61 Cygni LKi^^329 20 59
I1826 1 381 S. Re-exam. ....
I1826 1 272 Nova S 774 i20 59
!j826! I 273 II. 97. .••. S 775
21
2 51N
34 44 N
37 52N
33 26N
29 29 N
59 31
59 54
5 J9
3 4
47 9
45 12
"/
nf
sp
np
.3.613
23.249
15.425
15.444
14.324 I
. 3.576 Unaltered
Binary ; mean mot. + 0°. 730.
Epoch 1825.70.
detailed in the present, and preceding communications.
Vol.
for
Star's Name.&c.
Observer and
Number.
Decl.
Position.
Qoadrant.
Distance.
Remarks.
1826
1826
1826
1826
1826
1826
1826
1826
1826
1826
1826
1826
1826
1826
1826
1826
1826
1826
1824
1824
1826
1826
1826
1826
1826
1824
1826
273
274
276
276
Struve, 709.
1789.213 —
Nova
Struve, 710
Nova ....-.-..
277
278
279
280
281
19 Bode Equulei
^Equulei
H.C. 197
Nova
Struve, 718. . . .
281
282
283
283
284
327 Bode Cygni
I Pegasi
H.C. 197
Nova
69 Cygni
284
285
285
369
370
Nova . . .
Nova . . .
Nova . . .
jS Cephei
3 Pegasi.
286
287
Nova .
III. 71
288
288
289
AandB.
. A and C
76 Cygni
III. 72.
Pegasi
370
/* Cygni
1824
1824
1824
289
290
373
374
375
. . I and 2
. . I and 3
79 Cygni; A andB.^
, A and C . -
'45-74-^
I4S-S7-
ni.74
S...
s...
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
H&S330
H&S331
794
795
79^
797
798
H&S332
S....799
H&S333
H&rS334
H&S335
m.
2
2
2
2
2
43 N
26 N
50 N
iN
16N
30 53
32 3»
5 55
79 15
58 20
4
6
7
II
13
6 28N
9 17N
8 23S
8 48N
52 15 N
82 58
4« 3
82 22
84 53
26 33
13
H
H
18
18
52 19N
19 3N
7 20S
12 56N
35 33 N
32 22
40 II
6 30
56 29
II 22
20
24
25
26
28
10 19 N
33 2N
19 56N
69 46 N
5 48N
68 5
79 23
41 40
19 35
78 58
3»
33
34
35
35
36
'36
"46
46
49
35 3;N
56 41 N
39 S9^
56 46 N
9 3N
72 3
31 33
69 3
40 52
33 35
52 59
27 56 N
3-7 29 N
18 *sVn
54 59N
5 6N
23 4
28 43
30 39
50 8
20 15
76 u
33 29
np
np
sp,nf
«/
nf, sp
..17.685
.. 6.825
...3.087
» 54-785
...2.933
np
«/
sp
sf, np
3 3-24»
. . 26.240
. . . 4-837
. . . 2.642
. . . 6.641
Annual mot. =— o*» 838 in Pos. &+o".
in Dist.
np
np
sp
48.739
36.861
36.784
. 3-480
40-305
np, sf
sp,nf
np
sp
np
np
sp
«/
np
. 1. 195
.4.321
. 2.580
13.163
39-525
No notable change.
Perhaps a very slow change of Pos.
. 8.172
11.945
19-383
5.645
12.150
18.514
Change of Pos. —3° 51', of Dist. +0''.^
Ch. of Pos. — 4°.54 & +o".77 in Dist!
Sir W. H. has no measures of this stai
Pos. unchanged.
«/
«/
np
sp
... 5.744
.3 37.401
.2 33.170
2 J min. ±:
. . . 22 052
.. . 20 308
. . 10.093
Diminished ia Distance.
1824
1826
1826
1826
iS26
375
290
291
291
292
Near III. 74
1789.213 ...
H.C. 571...
29 Aquarii. .
Nova
H&S336
S 800
S 8oi
S 802
S....803
49
49
52
53
57
5 6N
61 45 N
12 51 S
17 49 S
12 48 N
1824
1826
1826
1824
1824
376
292
293
376
377
I Cephei
1789.218
Nova
P. XXII. 1 1. 12
'45-56
H&S337
S 804
S 805
H&S33S
H&S339
21 58
22 o
22 o
22 3
22 4
63 45 N
69 20 N
36 45 N
58 25 N
21 53S
1826
1826
1824
1824
1826
1824
1824
1826
1824
1824
1824
1826
293
294
378
378
382
379
380
295
381
382
383
383
180 Bode Cephei.
Nova ,
145.120 ,
I Lacertae
33 Pegasi.
S 806
S 807
H&S 340
H&S341
S. Re-exam.
H&S 342
22
22
22
2Z
22 15
81 58N
28 41 N
69 17 N
36 5iN
19 56N
Struve, 751
Nova ......
145.64.....
53 Aquarii. .
^ Aquarii. . .
H&S 343
S 808
H&S 344
H&S 345
H&S 346
S. Re-exam.
22 16
22 16
22 17
22 17
22 20
65 50 N
21 5 S
.44 27 N
17 39 S
o 57S
44 o
55 21
30 4
26 38
7 9
sp
*/
sp
sp,nf
I 45.858
I 2.836
. . 20.453
..4.370
..,. 3.288
23 »5
83 43
22 40
45 13
30 42
np
«/
np
• 5-817
16.606
12.774
22.094
. 5.170
8
15
»5 3»
78 43
II
45
12
21
77
75
*/
sp
sp
sp
np
13-567
. 1.794
14.839
15.619
»5-732
56.045
Epoch 1824.84.
2 37
64 35
o 5
3 7
89 29
88 56
«/
nf
np
sp
nf
. ^723
• 6.457
. 4-238
10.032
. 4.989
. 4.014
Binary ; mean mot. — 0*^.4484.
Epoch 1825.73.
MDCCCXXVI.
A synoptical view of the results afforded by the observations , &c.
385
295
296
386
296
297
297
298
299
387
star's Name, &c.
a Ccphei
Nova
H.C. 108
8 Lacertse i and 2 ,
1 and 3 .
Struve, 758
H.C. 181
10 Lacertae
Nova
12 Lacertze
213 Bode Aquar. .
299
300
388
301
301
302
389
303
303
39^
1789.219 . . . .
1 6 Lacertae . .
Nova
Nova
P. XXII. 306
n Pegasi
t' Aquarii
231 Bode Aquar. 1&2
I and 3
Aquarii
Nova
Observer and
Number.
H&S347
S 809
S 810
H&S348
S 811
S 812
S 813
S 814
S 815
H&S349
S....8I6
S....8I7
H&S350
S 818
S 819
S 820
H&S35I
S 821
S 822
H&S 352
h. m.
22 23
22 24
22 25
22 28
22 29
22 30
22 31
22 33
22 33
22 34
22 35
22 38
22 39
22 40
22 41
22 42
22 48
22 50
22 57
22 59
Decl.
57 30 N
6 31N
3 19N
38 42 N
37 57 N
28 S
7N
7N
17N
II S
17N
oS
9S
33' s
23 N
71 56N
40 39 N
26 49 N
32 26N
31 5'N
78 44
79 41
55 35
85 39
55 15
6-/ 26
56 46
41 19
9 42
73 28
51 19
68 56
22 47
24 24
72 33
22 24
20 31
9 21
44 41
82 II
70 48
58 19
Quadrant.
Sp
np, sf
*/
sp
np
sf,np
np,sf
np
np
sp
*/
np
np,sf
np
nf
nf
. 41.612
. 12.897
. 14.062
. 22.674
22.520
.21.175
. . . 6.01 1
I 0.444
. . 18.522
I 12.073
. . . 3-398
29.823
30-536
• 4.349
57-381
13-438
• 3-712
Sir W. H. has no measures of this star.
DifF. of Pos. 2° 53'; dimin. of Dist. 5".!.
Pos. changed 3° 54'.
0.895
4.541
. 6.850
• 3.434
. 8.716
Remarke.
No material change.
Unaltered.
39»
304
304
305
305
H. C. 242
2 Cassiopeiae
H.C. 191
Nova
H.C. 191; AandB.
AandC.
H&S 353
S....823
S 824
S 825
S 826
23 2
23 2
23 2
23 2
*3 5
46 59 N
58 21N
12 54S
35 55 N
9 52S
17 o
73 20
12 41
49 58
86 10
19 10
sp
sf
np
14.709
46.683
. 4.207
5-331
26.276
38.168
Sir W. H. gives no measures of this star.
306
392
307
308
308
4'' Aquarii . . .
94 Aquarii . . .
Nova
P. XXIII. 69.
xPiscium. . . .
S 827
H&S 354
S 828
S 829
S....830
23 6
23 10
23 13
23 H
23 18
10 4S
14 26 S
34 29 N
9 27S
o 16N
41 8
76 41
86 13
4 4
74 56
np .
np
sp
np
np
49-835
14.993
.5.117
. 7.981
30.090
Probably not Sir W. H's. star.
Sir W. H. has no measures of this star.
308
393
309
310
393
Struve, 783.. .
Anonyma
II. 94 or Nova ?
H.C. 128
107 Aquarii. . . .
S....831
H&S 355
S 832
S....833
H&S 356
23 21
23 22
23 23
23 32
23 37
4 17N
57 32N
42 50 N
5 17N
19 41 N
84 1
o o
41 52
41 34
53 30
sp
P
np
np
11.681
13953
. 4-389
H-575
. 5.056
Pos. changed probably 6° 42', if II. 94.
310
3"
394
IV. 107
20 Piscium
28 Bode Andr. 1 & 2
I and 3
S....834
S....835
H&S 357
395
3"
Nova
H&S 358
S....836
23 38
23 39
23 43
23 46
23 49
27 28 N
3 46S
36 54 N
30 52 N
23 22 N
396
397
312
312
T Cassiopeiae ....
37 Bode Androm.
Struve, 794. . . .
9 Cassiopeise ....
H&S 359
H&S 360
S....837
S....838
23 50
23 51
23 54
23 55
54 45 N
32 43 N
65 6 N
61 17N
53
31
17
»3
0
»7
45
25
59
11
44 38
57
4»
81
38
19
24
74
23
nf
np
p,nf
np
np
32.248
50.924
. 5.011
45.941
41.297
. 9.361
Differs 3° 10' from Sir W. H's. Pos.
np
sp
nf
sp
. 2.924
. 5.263
15.427
5-423
Doubtful if changed or not.
Manifestly not Sir W. H's. star.
Sloaiie Street, No. 132,
April 1 2th, 1826.
JAMES SOUTH.
A careful revision of the former communication on Double
Stars, Phil. Trans. 1824. iii. has led to the detection (among
several errata of trifling importance), to the following of a graver
character, which the reader of that paper is earnestly requested
to correct in his Copy.
Page, &c.
Error.
Correction.
124.
216.
325-
337.
.Mean 54Cancri. .
48.845- •
4-13
.Near 54 Cancri.
40.845.
44.6..,
337 twice and in Index, Star No. 301
338
355
167 and in Index No. 144.
101 and in Index No. 79
323 twice and in Index No. 287...
Index No. 105 , . . . .
Index No. 110 in Column of Decl.
Index No. 278
Index No. 222 ,
{
97.60
.23.467..
Z= + 1.44...
Z = — 0.12. . .
.-.73° 50'
••••73 54
••••73 52
....i6".988
....67° 46'
9 42
... .12 17
...278
Mean mot. — 2°. 13
107.60. ..
25.871..
.Z = — 1.44...
.Z = + 0.12...
••••72° 50'
••••72 54
••.•72 52
....i5''.966
22° 14'
9 iz
... .17 12
..•278
Mean mot. + 2°. 13
^n^ata to be corrected in the present Memoir^
Page 209, /or " between 36 and 38," read north following 36.
353>/o^" 1825.252," rejrf 1825.52.
vi. (Index) H. and S. 74 ; for -f o°.oo9," read + 0°. 109.
viii. (Index) S. 600 ; Re-exam, add in col, of Remarks, the word '« Binary.
From the Press of
JV. NidOL,
Cleveland-row, St, Jameses.
PHILOSOPHICAL
TRANSACTIONS
OF THE
ROYAL SOCIETY
OF
LONDON.
FOR THE YEAR MDCCCXXVI.
PART II.
LONDON:
PRINTED BY W. NICOL, SUCCESSOR TO W. BULMER AND CO.
CLEVELAND-ROW, ST. JAMEs's;
AND SOLD By G. AND W. NICOL, PALL-MALL, PRINTERS TO THE
ROYAL SOCIETY.
MDCCCXXVI.
Cv3
ADVERTISEMENT.
. 1 HE Committee appointed by the Royal Society to direct the
publication of the Philosophical Transactions, take this opportunity
to acquaint the Public, that it fully appears, as well from the
council-books and journals of the Society, as from repeated de-
clarations which have been made in several former Transactions,
that the printing of them was always, from time to time, the
single act of the respective Secretaries^ till the Forty-seventh
Volume : the Society, as a Body, never interesting themselves
any further in their publication, than by occasionally recom-
mending the revival of them to some of their Secretaries, when,
from the particular circumstances of their affairs, the Transactions
had happened for any length of time to be intermitted. And
this seems principally to have been done with a view to satisfy
the Public, that their usual meetings were then continued, for the
improvement of knowledge, and benefit of mankind, the great
ends of their first institution by the Royal Charters, and which
they have ever since steadily pursued.
But the Society being of late years greatly enlarged, and their
communications more numerous, it was thought advisable that a
Committee of their members should be appointed, to reconsider
the papers read before them, and select out of them such as they
should judge most proper for publication in the future Trafisac-
tions ; which was accordingly done upon the 2()th of March,
1752. And the grounds of their choice are, and will continue to
be, the importance and singularity of the subjects, or the advan-
tageous manner of treating them ; without pretending to answer
for the certainty of the facts, or propriety of the reasonings,
contained in the several papers so published, which must still
rest on the credit or judgment of their respective authors.
It is likewise necessary on this occasion to remark, that it is
an established rule of the Society, to which they will always
adhere, never to give their opinion, as a Body, upon any sub-
ject, either of Nature or Art, that comes before them. And
therefore the thanks, which are frequently proposed from the
Chair, to be given to the authors of such papers as are read at
their accustomed meetings, or to the persons through whose
hands they received them, are to be considered in no other light
than as a matter of civility, in return for the respect shown to
the Society by those communications. The like also is to be
said with regard to the several projects, inventions, and curiosi-
ties of various kinds, which are often exhibited to the Society;
the authors whereof, or those who exhibit them, frequently
take the liberty to report, and even to certify in the public
news-papers, that they have met with the highest applause and
approbation. And therefore it is hoped, that no regard will
hereafter be paid to such reports and public notices; which
in some instances have been too lightly credited, to the disho-
nour of the Society.
CONTENTS.
I. An Account of the construction and adjustment of the new
Standards of Weights and Measures of the United Kingdom of
Great Britain and Ireland, By Captain Henhy Kater,
F,R, S. - - - - page i
n. description of an improved -Hygrometer. By Mr. Thomas
Jones. Communicated by Captain Henry Kater, F.R. S. 53
III. Observations on the changes which have taken place in some
aritient alloys of copper. By John Davy, M D. F. R. 5. In
a Letter to Sir Humphry Davy, Bart, Pres,R, S, -55
IV. Additional proofs of animal heat being influenced by the
nerves. By Sir Everard Home, Bart, V, P, R, S. 60
V. The Croonian Lecture. On the structure of a muscular fibre
from which are derived its elongation and contraction. By
Sir Everard Home, Bart. V. P. R.S. - - 64
VI. An account of the heat of July, 1825 ; together with some
remarks upon sensible cold. By W. Heberden, M, D.
F.R,S. - - - - -69
VII. On the transit instrument of the Cambridge Observatory ;
being a Supplement to a former Paper, By Robert Wood-
house, Esq, Plumian Professor of Astronomy in the University
of Cambridge, - - - - 75
VIII. Account of a series of observations, m^de in the summer of
the year 1825, for the purpose of determining the difference of
meridians of the Royal Observatories of Greenwich and Paris ;
drawn up by J. F. W. Herschel, Esq. M, A. Sec. R. S.
Communicated by the Board of Longitude, - - 77
IX. Observations on the poison of the common toad. By Johjt
Davy, M. D. KR.S. - - - page 127
X. On the magnetizing power of the more refrangible solar rays.
By Mrs. M. Somerville. Communicated by W. Somerville,
M. D. F. R. S. Feb. s. 1826, - - 132
XI. On the mutual action of sulphuric acid and naphthaline, and
on a new acid produced. By M. Faraday, F. R. S. Cor^
responding Member of the Royal Academy of Sciences ^ &c. ^c.
Communicated January 12, 1826, - -- 140
XII. On the nervous circle which connects the voluntary muscles
with the brain. By Charles Bell, Esq. Communicated by
the President, January 25, 1826, - - - 163
XIII. On the constitution of the atmosphere. By John Dalton,
Esq.F.R.S. - 174.
PHILOSOPHICAL
TRANSACTIONS.
I. An Account of the construction and adjustment of the new
Standards of Weights and Measures of the United Kingdom of
Great Britain and Ireland, By Captain Henry Kater,
F. R. S.
Read November 24, 1825.
Ike weights and measures of the United Kingdom of
Great Britain and Ireland are founded upon a standard, the
length of which is determined by the proportion it bears to
that of the pendulum vibrating seconds of mean time in
London. The length of this pendulum I have stated to be
39,13929 inches of Sir George Shuckburgh Evelyn's
standard scale; and the experiments from which this con-
clusion is deduced, are detailed in the Philosophical Transacr
tions for 1818. The important consequences, however, which
attach to this result, render it necessary to examine with
what degree of confidence it may be received.
In the Paper to which I have alluded, it is mentioned that
a series of experiments had been made previous to those
detailed ; the result of which was rejected, in consequence
of its being discovered, after their completion, that the steel
MDCCCXXVI. B
2 Captain Kater*s account of the
plates, on which the pendulum had rested during the expe-
riments, had suffered penetration by the knife edges. The
length of the seconds pendulum however, deduced from
these first experiments, did not differ more than two ten-
thousandths of an inch from the final determination.
It may also be seen, that in repairing the knife edges after
the first set of experiments had been concluded, one of them
was broken ; and when replaced by another, the distance
between the knife edges was increased about one hundredth
of an inch ; so that two results, differing by so small a quan-
tity from each other, may be considered as having been
obtained by two different instruments.
The Philosophical Transactions for 1819 contain an account
of experiments for determining the variation in length of the
seconds pendulum at the principal stations of the Trigonome-
trical Survey of Great Britain. For this purpose I constructed
an invariable pendulum, the number of vibrations made by
which being observed in London, and also at the principal
stations of the Trigonometrical Survey, the length of the
seconds pendulum, at such stations, could readily be deduced
from the previously known length of the pendulum vibrating
seconds in London.
In this manner, the length of the pendulum vibrating
seconds at Unst was found to be S9,i7i46 inches, and at
Leith Fort 39,15554 inches.
The " Reciieil d' Observations Geodesiques /' &c. which may
be considered as a fourth volume of the " Base du Systeme
metrique," affords me an opportunity of comparing these
last results with those of M. Biot, whose very valuable
labours for determining the length of the pendulum vibrating
new standards of weights and measures. 3
seconds at various stations, from Unst to Formentara, are
there detailed. In these experiments M. Biot employed the
method of Borda, which requires that the absolute length of
tlie pendulum should be obtained by actual measurement at
each station. M. Biot's observations and mine, both at
Unst and Leith Fort, were made at the same stations ; and
M. Biot found, from the mean of fifty-six series, using
different measuring rods and various pendulums, the length
of the second pendulum at Unst to be ,994943083 metres,
and at Leith Fort ,994524453 metres.
Converting these results into inches of Sir George Shuck-
burgh's scale, by taking the length of the metre at 39,37079
inches, as given in the Philosophical Transactions for 1818,
we have the length of the seconds pendulum at Unst, after
reduction to the level of the sea, 39,17176 inches, and at
Leith Fort S9A55S9 inches, the first differing from my
determination +,00029, and the latter —,00015 of an inch.
The difference of results obtained by methods totally dissi-
milar being so small, and with contrary signs, it may be
reasonably inferred from them, as well as from what has
been before advanced, that the length of the pendulum
vibrating seconds in London has been determined to within
one ten-thousandth of an inch of the truth.
From the near agreement of the results of the French and
English experiments on the length of the pendulum, it may
be inferred that the length of the French metre, expressed in
parts of Sir George Shuckburgh's scale, is probably not
erroneous one ten thousandth of an inch.
From an account recently published by Captain Sabine,
F. R. S. of his valuable experiments for determining the vari-
^ ' Captain Kater's account of the
ations in length of the seconds* pendulum, doubts may be
inferred of the accuracy of the method which I employed in
the observations for ascertaining the length of the seconds*
pendulum in London, as well as in those which have been
made with the invariable pendulum. It is asserted, that
taking a mean between the disappearance and re-appearance
of the disk, is a more correct method of observation than
that which I have pursued ; and that the intervals between
the coincidences obtained by observing the disappearances
only of the disk, would be productive of error.
With respect to the convertible pendulum, it will be seen
on referring to the Philosophical Transactions for 1818, that
the disk was made to subtend precisely the same angle as the
tail-piece of the pendulum ; so that at the moment of disap-
pearance of the last portion of the disk, its centre coincided
with the middle of the tail-piece, a circumstance which, in
my method of observing is indispensable, when the object is
to obtain the true number of vibrations made by the pendu-
lum in twenty-four hours.
With the invariable pendulum, from causes unnecessary
here to detail, the circumstances were somewhat different, the
disk subtending a less angle than that of the tail-piece of the
pendulum ; in consequence of which, the interval between the
apparent coincidences was lessened, and the inferred number
of vibrations in twenty-four hours diminished about two-
tenths of a vibration ; but as the experiments with the inva-
riable pendulum are intended to be merely comparative, and
should therefore be made as nearly as possible in every
respect under similar circumstances, no part of the apparatus
being changed, nor any alteration made in the pendulum of
new standards of weights and measures. 5
the clock, this constant difference of the number of vibrations
from the truth will not affect the ultimate deductions. As
the most direct method of removing any doubts which may
be entertained upon this subject, I shall add a comparative
Table of the successive differences of the number of vibra-
tions in twenty-four hours, which I have computed from the
whole of Captain Sabine's observations, by employing the
disappearances only, of the disk.
Differences by the
method of
disappearances.
Differences by
the method of dis-
appearances
and re- appearances.
Difference of the
results.
Stations.
Vibrations.
Vibrations.
Vibrations,
St. Thomas
Maranham
Ascension .
Sierra Leone .
Trinidad .
Bahia . .
Jamaica
New York
London
Drontheim
Hammerfest
Greenland .
Spitzbergen
9>62
i3>29
4.97
0,85
S'S^
12,40
72,72
41,88
38,62
22,48
9'53
12,62
9,62
13.33
4.97
0,83
5.50
12,46
72,71
4i>8i
38.73
22,44
9,48
12H.9
0,00
— 0,04
0,00
-1-0,02
+ 0,01
— 0,06
+ 0,01
+ 0,07
— o,ii
+ 0,04
-j-0,05
-Ho,oi
Mean . .
0,00
As the comparative results, by the method of disappear-
ances, would to a certain degree be vitiated by the use of a
disk of a different size, the observations made in London in
1824 with a silver disk are omitted.
The differences of the results being so minute, and the
mean of the whole being absolutely nothing, the conclusion
i& warranted that the method of observing coincidences by
6 Captain Kater's account of the
disappearances alone is productive of no error, if the ob-
servations are made as nearly as may be under similar
circumstances.
With respect to the absolute length of the pendulum in
London, as determined by means of the convertible pendu-
lum, it must be evident from what has been advanced, that
the method of observation by disappearances alone could,
on that occasion, have been productive of no error, as the
disk subtended precisely the same angle as the tail-piece of
the pendulum.
In the Philosophical Transactions for 1821 will be found
" An account of the comparison of various British Standards
of linear measure \" and it will there be seen that the differ-
ence between Sir George Shuckburgh's standard scale and
a standard yard of 1 760, made by Bird, and in the custody of
the Clerk of the House of Commons, is so very small, that
they may be considered as " perfectly identical." This
yard, under the denomination of " the Imperial Standard
Yard,'' has been declared by Parliament, on the recommen-
dation of the Commissioners of Weights and Measures,* to
be the " unit, or only standard measure of extension" of the
United Kingdom ; consequently, the length of the pendulum
before given is expressed in parts of the Imperial Standard
Yard.
The measures of capacity being dependant upon the weight
of a cubic inch of distilled water, it became necessary to
* A commission was appointed by letters patent under the Great Seal of the
United Kingdom in 1818, '* For considering how far it might be practicable and
advisable to establish a more uniform system of Weights and Measures," the
members of which were, the late Sir Joseph Banks, Sir George Clerk, Mr. Davies
Gilbert, Dr. W. H. WoUaston, Dr. Thomas Young, and Capt. Henry Kater.
new standards of weights and measures. ^
consider the degree of reliance which might be placed upon
the accuracy of the experiments made by Sir George Shuck-
burgh on this subject.
A cube, a cylinder, and a sphere of brass were used in
these experiments ; and in consequence of some difficulties
which occurred, the weight of these, both in air and in dis-
tilled water, was so repeatedly ascertained by Sir George
Shuckburgh, as to leave no reasonable doubt of the accuracy
of his conclusions. But as the linear dimensions of the cube,
sphere and cylinder, might not have been determined with
equal precision, it was thought adviseable to repeat these
measurements. This was accordingly done ; and though in
detail they differed somewhat from Sir George Shuckburgh's
determinations, yet, fortunately, the variations were such as
nearly to counterbalance each other, and to occasion little
difference in the ultimate result, as may be seen in an account
of these last mentioned measurements given in the Philoso-
phical Transactions for 1821,
Sir George Shuckburgh's results having been expressed
in terms derived from the mean of several standard Troy
weights, of one and of two pounds, kept at the House of
Commons, the Commissioners of Weights and Measures
thought it desirable that the Troy pound, which differed the
least from this mean, should be taken as the unit of weight ;
and therefore recommended that the Parliamentary Standard
Troy pound of 1758 should remain unaltered; and this has
been accordingly declared by the Legislature to be the ori-
ginal " unit, or only standard measure of weight, from which
all other weights shall be derived ;" and that it is to be
denominated '* the Imperial Standard Troy Pound."
8 Captain Kater's account of the
From Sir George Shuckburgh's data, and the before-
mentioned measurements of the cube, cylinder and sphere,
the Commissioners of Weights and Measures determined the
weight of a cubic inch of distilled water, weighed in air by
brass weights at the temperature of 62° of Fahrenheit's
thermometer, the barometer being at so inches, to be equal
to two hundred and fifty-two grains, and four hundred and
fifty-eight thousandth parts of a grain, of which the Imperial
Standard Troy pound contains five thousand seven hundred and
sixty ; and also that the avoirdupois pound, which has long
been in general use, though not established by any act of the
Legislature, is so nearly seven thousand grains, that they
recommended that seven thousand of such troy grains be
declared to constitute a pound avoirdupois.*
The Commissioners of Weights and Measures also recom-
mended that the gallon measure should in future be that
which contains ten pounds avoirdupois of water in ordinary
circumstances (that is to say, the temperature of the water
being 62° of Fahrenheit's thermometer, and the barometer
SO inches) ; and this, under the denomination of " the Impe-
rial Standard Gallon," was declared to be the unit and only
standard measure of capacity, and that eight such gallons
should be a Bushel.
The Act for " ascertaining and establishing uniformity of
" Weights and Measures" having been passed by Parliament,
to the effect before-mentioned, the Lx)rds Commissioners of
His Majesty's Treasury expressed their hope, that some of
* For the manner in which the weight of a cubic inch of distilled water was
deduced, see the Appendix to the Third Report of the Commissioners of Weights
and Measures.
new standards of weights and measures, g
the Commissioners of Weights and Measures would afford
their assistance in directing the executive measures necessary
for the accomplishment of its objects. In compliance with
this request, I undertook to superintend the construction, and
to adjust the principal standards to be deposited at the
Exchequer, Guildhall, Dublin, and Edinburgh.
Mr. Troughton, the first of our English artists having,
in consequence of his advanced age, declined undertaking to
make the standards, I directed Mr. Dollond to prepare those
of linear measure ; and employed Mr. Bate, an artist who,
as hydrometer maker for Revenue purposes, had been accus-
tomed to nice operations in weighing, to construct those of
weight and measure.
Brass being peculiarly liable to decomposition in the
atmosphere of London, I directed Mr. Bate to make some
experiments, to ascertain the proportions of tin and copper
which might produce a metal equal in hardness, and which
might be worked with the same facility as hammered brass ;
and after some trials it was found that a mixture of 576 parts
of copper, 59 of tin, and 48 of brass, afforded a beautiful
metal, which possessed the qualities I sought.
In order to avoid any innovation but such as might be ab-
solutely necessary, it was deemed expedient in constructing
the bushel, to adhere as nearly as possible to the form of that
known by the appellation of the Winchester bushel. It was
therefore directed to be made cylindrical, the interior dia-
meter being about i8|- inches, the exterior 19J inches, and the
depth about 8^ inches, and intended to contain eighty pounds
avoirdupois of distilled water. In order to give the bushel
MDCCCXXVI. C
1 o Captain Kater's account of the
additional strength, it was cast with two projecting hoops,
one to which the bottom was screwed, and another at the
distance of about half an inch from the top.
Considerable difficulties arose in casting the bushel ; out
of twelve, only five proved sound enough for use ; but by
varying the process, they were at length procured sufficiently
perfect. Much credit is due to Mr. Keir, the engineer em-
ployed by Mr. Bate in turning the bushels, for the beauty
and perfection of his work.
The form of the gallon measure occupied much of my
attention. It was necessary that it should be such as to
enable me to determine the weight of distilled water it should
contain with the least liability to error. The conical form
was therefore adopted ; the mouth being made cylindrical,
and one and a half inches diameter : the top was ground
perfectly flat, and the edge so rounded off, that the contents
might be poured from it into any other vessel without run-
ning down the side. The cone was placed in a cylinder about
four inches high, in which handles were formed, and which
served at the same time to protect the gallon from injury,
and to prevent any change of temperature which might arise
from handling. The quart and the pint measures were of
the same form on a smaller scale.
The weights were of brass, and nearly of a spherical
form, but flattened at the bottom. Into the top was screwed
a button ; beneath which a small cavity was left to receive
such' minute pieces of wire as might be found requisite to
make up the standard weight. This button served also to
lift the weight by means of a strong wooden fork.
new standards of weights and measures. 1 1
The Imperial Troy pound is in the custody of G. Whittam,
Esq. Clerk to the House of Commons, who obligingly per-
mitted me to compare two weights with the standard at his
house in Abingdon-street. These being intended merely as
rough models for Mr. Bate to copy, it was not thought
necessary to waste time in adjusting them with the utmost
precision, and they were left a little in excess.
The five Troy pounds being completed by Mr. Bate from
the copy of the Imperial pound taken at Mr. Whittam's, I
proceeded to compare them with the Imperial Troy pound,
which was then confided to my care for that purpose. The
balance employed in making the comparisons was made by
Mr. Robinson, an artist who has directed much of his atten-
tion, and with great success, to the improvement of this
instrument. The beam is only ten inches long, and toge-
ther with the scale pans weighs eight hundred grains. The
scale pans are attached to agate planes, which rest upon knife
edges. The ultimate angle of the central knife edge is
120 degrees. This balance, with one pound avoirdupois in
each scale, it may be seen by the following details, varies
immediately one division, equal to about one-tenth of an
inch, on the addition of one-hundreth of a grain.
Adjustment of the standard troy pounds.
In order to distinguish the troy pound weights from each
other, they were marked in the following manner :
life Captain Kater's account of the
That which I shall call |T^ P°
No. 1. \ 1824
No. 2.
all CY
.1. (.1
CT
I 1824* a dot after the figures.
No. 3. I •'■ * *^ • * dot under the letter D.
( 1834
No. 4. < * . a dot under the letter D, and another
^- * * ^l824. dot after the figures.
T. -r ( T y P ° a dot under the letter Y, another dot
No. 5' \ ^QnA * under the letter D, and a third dot
(lei 24. after the figures.
The Imperial Standard troy pound was put into the scale,
and counterpoised. The division and fraction of a division
which would have been pointed out by the index, had the
beam been allowed to come to a state of rest, was ascertained
by taking the mean of the extremes of the vibrations, when
their extent did not exceed one division. By this much time
was saved, and it is presumed greater accuracy attained.
The standard pound was then removed and replaced by the
copy, and the point of rest determined as before : the dif-
ference between these means converted into parts of a grain,
gave the error of the copy. The same method was followed
in the adjustment of all the weights.
No. 1 . being too heavy, was laid aside for the present.
No. 3. being too light for the limits of the index, was also
set aside.
By many careful trials, one-hundredth of a grain occasioned
a variation in the index of 0,67 divisions.
new standards of weights and measures.
IS
Standard Pound
Divisions.
No. 3.
DiTisions.
Error
Divisions.
Mean.
Error
ingrdns.
+ 0,5
+ 1,0
+ i>o
— a,o
-1.5
— 2.5 3
— 2,5
— >037
No. 4.
+ 1,4
+ 0,1
+ 0,3
+ 0,4
+ 0,9
+ 0,0
+ 0,4
+ 0,3
—0.5 ")
— 0,1 r
+ o,x (
—0,1 }
— 0,15
— ,0022
No. 5.
+ 0,5
+ 0,0
+ 0,4
+ 0,2
+ 0,1
+ o,i
— 0,1
+ 0,3
+ 0,3
— 0,3
— 0,4 -N
— 0,1 #
— 0,1 V
-0.5 I
— o>4 J
— 0,3
— ,0044
Wires of the following weights were now added :
To No. 2. - - ,020 grains.
3. - - ,050
4. - - ,002
5. - - >oo4
The centre of gravity of the balance was raised, so that
by frequent trials, one hundredth of a grain occasioned the
index to vary one division.
Standard Pound
Divisions.
No. 3.
Divisions.
Error
Divisions.
Mean.
Error
in grains.
— o>5
— 0,6
— 0,2
+ 0,1
— 0,2
— 0,5
— 0,1
+ 0,3
— 0,6
+ 0,1
— 2,1
— 2,1
+ 0,4 -J
+ 0,9
-0,4 I
+ o>o ^
— 1,9
— 1,6 J
— Oyf3-
— ,0043
The centre of gravity was lowered, so that one-hundredth
of a grain was equal to eight-tenths of a division.
14
Captain Kater's account of the
Standard Pound
Divisions.
No. 3.
Divisions.
Error
Divisions.
Mean.
Error
in grains.
— 0,5
0,0
— 0,3
— 0,3
— 0,8
— 0,9
— 0,8
— 0,7
-0,3 -)
-0,9 1
-0,5 f
-0,4 J
— 0,52
— ,0065
No. 4.
+ 0,3
+ 0,1
+ 0,5
— o,x
0,0
— 0,1
+ 0,3
+ 0,1
— 0,2
0,0
— 0,4
— 0,1
0,0 ■"
0,0
— 0,7
+ 0,1
— 0,4
0,0
-
— 0,17
— ,0021
No. 5.
— 0,1
+ 0
+ o,i
+ 0,2
+ 0,2
+ 0,3
— 0,2
— 0,2
0,0
+ 0,2
+ 0,2
— 0,2
— 0,1
— 0,1 -
— 0,1
+ 0,1
0,0
— o,i
— 0,5
+ 0*1 ^
^
— 0,08
—,0010
The following quantities were added to the different
weights :
To No. 3.
4.
5.
iQ05 grains.
,002
,00a
Mr. Robinson exchanged the balance I had hitherto used
for another, which he thought superior. The mean of many
trials gave 0,7 of a division for the variation occasioned by
one-hundredth of a grain.
new standards of weights and measures.
15
Standard Pound
Dmsions.
No. 2.
Divisions.
Error
Division*.
Mean.
Error
ingrains.
0,0
+ 0,1
+ 0,3
+ 0,1
— 0,1
+ 0,1
+ 0,3
+ a,4
+ 0,2
+ 0,3
+ 0,2
+ 0,4
+ o»3 "^
+ 0,3
— o,i
+ 0,2
+ o>3
+ 0,3 J
»•
+ 0,2
+ ,0029
No. 3.
-0,4
-0,9
— 0,8
- '>S
— 1,0
— i,o
- 1,4
-2,3
-0,6 -^
— 0,1 1
-0,6 f
-0,8 J
— 0,52
- ,0074
No. 4.
+ 0,1
+ 0,1
0,0
0,0
+ 0,7
+ 0,7
+ 0,6
+ 0,7
+ o,s
0,0
+ 0,1
+ 0,8
+ 1,0
+ 0,8
+ 0,8
+ 1,2
+ 0,4 ■"
— 0,1
+ 0,1
+ 0,29
+ ,0041
+ 0,8
+ 0,3
+ 0,1
+ 0,2
+ o»5 .
>■
No. 5.
+ 0,1
0,0
0,0
0,0
+ 0,1
0,0
0,0
— 0,1
0,0 1
0,0
0,0 f
— o,i J
0,0
0,0
By many careful trials previous to the following compa-
risons, one-hundredth of a grain occasioned a variation of 0,9
of a division.
Standard Pound
No. 2.
Enor
Mean.
Error
Divisions.
Divisions.
Divisions.
in grains.
0,0
+ 0,1
+ 0,1 -]
0,0
0,0
0,0
— 0,2
+ 0,15
+ o»i
+ 0,3
+ 0,3
— 0,15
>
+ 0,16
+ ,OOl8
— 0,05
+ 0,35
+ 0.4
,
0,0
+ 0,3
+ 0,3 J
•
'
i6 Captain Kater's account of the
No. 1 . was reduced in weight, and being then too light,
,005 of a grain was enclosed in it and the following compa-
risons made :
Standard Pound
Divisions.
No.i.
Divisions.
Error
Divisions.
Mean.
Error
in grains.
— 0,2
— 0,15
— 0,35
— 0,5
+ 0,15
— 0,15
— o,3S
— 0,50
— 0,20
+ 0,70
— 0,10
+ 0,05 ^
— 0,20
— 0,15 [
+ 0,30 r
0,00 J
+ 0,09
+ >OOI
Added ,005 of a grain to No. 3.
Standard Pound
Divisions .
No. 1.
Divisions.
Error
Divisions.
Mean.
Error
in grains.
— 0,4
— 0,6
~o,4
— 0,1
+ 0,1
+ 0,1
— 0,65
— 0,50
— 0,40
— 0,20
+ 0,20
+ 0,20
— 0,25 -
+ 0,10
0,0
— 0,10
+ 0,10
+ 0,10 ^
>
0,0
,00
No. 3. \
+ 0,1
0,0
0,0
— 0,1
— o>i
0,0
+ 0,15
0,0
0,0
0,0
— 0,2
+ 0,2
+ 0,05 -\
0,0
0,0 .
+ 0,1 c
— o,i
+ Oj2
+ 0,04
+ ,0005
The wires which were found necessary to make each of
the copies equal to the Standard troy pound being enclosed,
the button was screwed in with a force sufficient to resist
any ordinary attempt to detach it ; but should such an en-
deavour ever be made with success and the wires be lost,
the following table contains an account of their number and
value.
new standards of weights and measures. 1 7
No. 1 . contains 1 wire = ,005 gr.
2. . . 1 wire =: ,020 gr.
3. . . 3 wires = ,050 + ,005 + ,005 gr.
4. . . 2 wires = ,002 + ,002 gr.
5. . . 2 wires = ,004 + ,002 gr.
In order to employ the whole of the preceding comparisons
in deducing a final result, it will be necessary to add to each
error given in the Tables the sum of the weights which were
enclosed after the determination of such error.
Troy Pound No, 1.
The mean of six comparisons gave for the
error of No. 1 .
The mean of six other comparisons
Troy Pound No. 2.
The mean of three comparisons gave for
the error of No. 2. — ,037 + ,02 =
The mean of six other comparisons
of six other comparisons
Troy Pound No. 3.
The mean of six comparisons gave
,0043 + ,005 + ,005 =: -
The mean of four other comparisons
gave — ,0065 + ,005 + ,005 = -
The mean of four other comparisons
gave — ,0074 + ,005 - - ' = -
The mean of six other comparisons - -
MDCCCXXVI. D
Grains.
+,001
- ,000
— ,0170
+ ,0029
+ ,0018
+ ,0057
+ ,0035
^ ,0024
+ ,0005
18
Captain Kater's account of the
Troy Pound No. 4.
The mean of four comparisons gave
— ,0022 -f- ,004 = - - -
The mean of six other comparisons gave
— ,0021 + ,002 := - - «
The mean of eight other comparisons
Grains.
+ ,0018
— ,0001
+ ,0041
Troy Pound No. 5.
The mean of five comparisons gave
— ,0044 + ,006 =----}- ,0016
The mean of seven other comparisons gave
— ,001 + ,002 = - _ - + ,0Q10
The mean of four other comparisons - - ,0000
In order to deduce a final mean from these results, each
result was multiplied by the corresponding number of com-
parisons, and the sum of the products thus obtained vv^as
divided by the sum of the comparisons. In this manner the
following errors of each of the troy pounds was determined.
Grains.
No. 1.
-
-
+ ,0005
2*
-
-
— ,0015
3.
-
-
+ ,0021
4.
-
-
+ ,0022
5.
-
-
+ ,0010
These errors being so small and mostly in excess, it was not
thought necessary to make any attempt to correct them.
The five troy pounds previous to their being delivered to
new standards of weights and measures. ip
me had been adjusted by Mr. Bate, and with the exception
of an excess of one hundredth of a grain common to all,
and which appears to have been the error of the copy taken
at Mr. Whittam's, the greatest difference from the preced-
ing results did not exceed four or five-thousandths of a
grain.
The adjustment of the five troy pounds occupied me from
the commencement till the middle of March 1825, during
which time Mr. Bate was engaged in preparing a balance
sufficiently strong to be used in determining the gallon
weights ; this balance was brought to my house on the 16th
of March.
I shall now proceed to describe the manner in which the
avoirdupois pound was derived from the troy pound.
For this purpose Mr. Bate made the following weights :
1 of 5760 grains.
'^ 2 — 2880
3 — 960
2 — 480
2 — 240
5 — 48
2—24
2 — 12
2—6
2 — 3
3 — 1
In all twenty-six weights.
Of the above weights the following were used to make up
an avoirdupois pound :
ao Captain Kater's account of the
5760
960
240
24
13
3
1
7000 grains.
In this manner five avoirdupois pounds were made and
adjusted by Mr. Bate.
Determination of the Avoirdupois Pound.
Wishing to avoid the verification of the numerous weights
used by Mr. Bate, and desirous of arriving at my object by
a road different from that which he had pursued, I used the
following method :
I caused Mr. Bate to make two weights each equal to six
troy pounds. These I compared with the Imperial Standard
Troy pound, and the five troy pounds already adjusted. I
had thus two known weights each equal or nearly so to six
troy pounds, one of which with the addition of 440 grains
gave me a weight equal to five avoirdupois pounds, subject
only to such error as might arise from inaccuracy in the
grains, and as I had had sufficient proof of Mr. Bate's care,
I had little to apprehend on this point.
The five avoirdupois pounds were then compared with
each of the six pound weights and 440 grains, and the mean
new standards of weights and measures.
21
taken, and thus the sum of the errors of the five avoirdupois
pounds became known. Assuming one of these pounds
(No. 1. ) as a standard, each of the others was then compared
with it, and their relative errors thus ascertained, from which,
and the sum of the errors of the five avoirdupois pounds, the
error of each was deduced.
The following is a detail of the comparisons.
The variation of the index was carefully ascertained to be
one division for one-tenth of a grain.
The sixTroy Pounds,
Divisions.
The 6 lb. weight.
No. 1. Divisions.
Difference
Divisions.
Mean.
Difference
ingrains.
— 0,4
+ 1,1
+ i,o
— 1,9
— 2,0
— i,o
— 4,0
-5,0
— 2,9
0,29
Added three-tenths of a grain to the 6 lb. weight No. i .
1,8
2,9
S'7
3>4
2>5
•0.5
■4,8
3>8
2,3
2,7
2,6
+ 1^3
— 1,9
+ 1,9
— 0,6
+ 0.7
— o,i
J
r T ' x'i
+ 0,2
+ 0,02
By several trials one-tenth of a grain occasioned a varia-
tion in the index of 0,7 of a division.
Captain Kater's account of the
The sixTroy Pounds,
DiTisioas.
Ui
0,0
— 1,0
— 2,2
The 6 lb. weight,
No. 3. Divisions.
•2,0
■4.8
3'6
Difference
Divisions.
2,0
3.8
1,6
1.4
}
Mean.
2,2
Difference
in grains.
— 0,31
Added two-tenths of a grain to the 61b. weight No. 2.
+ 1.5
+ 1,2
+ 1.7
-3.8
-3.8
— 4.8
— 0,2
_-5?2*4
— 2,3
— 1,9
— 3.3
~o,5
— 1.5
+ 1,2
-1,8
— 7.0
— 4,6
— 4'8
-3,6
-3.6
— 4>6
-4.3
— 2,0
— 2,7
— 0,5
+ 20
— 3.2
+ 0,2
— 4,6
— i»%
— I,
-'2,7
— 1,0
— ».54
— 0,22
Added 0,17 of a grain.
The 6 lb. weight No. 1.
The mean of four comparisons gave for the difference of
No. 1. from the six troy pounds, — ,29 + ,3 = +,01
The mean of six other comparisons - - +,02
The 6 lb. weight No. 2.
The mean of four comparisons gave for the difference of
No. 2. from the six troy pounds --,31 + ,2 -f->i7= +,0^
The mean of 1 1 other comparisons gave — ,22 +,17 = —,05
The final means of these results obtained in the same
manner as those of the troy pounds are as follows :
Grains.
The difference of No. 1, from the six troy pounds is +,016
of No. 2, _ _ _ - — ,020
The mean difference is — ,002
new standards of weights and measures. ' 23
The avoirdupois pounds were distinguished from each
other by the following marks.
That which I shall call C 1 P" Av''
No. 1. 1 1824
No. 2. -J
' 1824 • a dot after the figures.
-T ( 1 P° Av* a dot under the letter S, and another
i 1824* °°* ^^^ ^"® figures.
No. 4.
No. 5.
1 P^ Av* a dot under the letter D, another dot
under the letter S, and a third dot
8 24 • after the figures.
{':
These weights were successively compared with the avoir-
dupois pound No. 1 . which was taken both before and after the
others ; for this purpose Mr. Robinson's balance was used.
One hundredth of a grain occasioned a variation of 0,7 of
a division.
I
Avoirdupois Pounds.
No. I.
Divisions.
No. 2.
Divisions.
No. 3.
Divisions.
No. 4.
Divisions.
No. 5.
Divisions.
No. I.
Divisions.
+ 0,2
— 0,4
— 0,4
— 0,5
— 0,4
— 0,4
— 0,3
0 A
— 0,4
— 0,4
— 0,4
0 1
— 0,8
— 0,7
— 0,7
— 0,9
. — 0,8
— 0,8
-0,7
+ 0,3
— 0,2
— 0,5
— 0,2
Wjjj.
*-'»j
"»7
— 0,28
— 0,15
— 0,37
Mean.
— 0,37
— 0,72
— 0,8
— 0,15
— 0,21
Means.
By the above comparisons the difference of each weight
from No. 1. is as follows;
24
'Captain Kater's account of the
No. 2.
3.
4.
5.
u^nit*- ,i6 divisions = — ,002 grains.
. — ,16 . . = — ,002
. — ,51 . . = —,007
• — ,59 . . = — ,008
Sum of the differences — ,019
I now proceeded to compare the five avoirdupois pounds
with each of the 6lb. weights, to which 440 grains, taken
from Mr. Bate's weights, were added, and which together
made five pounds avoirdupois.
One tenth of a grain occasioned the index to vary one
division.
The 6 lb. weight
N0.I.
+ 440 gr. Divis.
The five
Avoirdupois Pounds,
Divisions.
Difference
Divisions.
Mean.
Difference
in grains.
— 1,0
— 0,8
+ 0,6
+ 1,8
+ 1^7
+ 1^5
0,0
+ 2,7
-1,9
— 2,2
— 3^9
—0,5
+ 2,2
+ 1>I
+ 0,1
+ I>I
— 0,4
— o>7
— 2,9
— 1,4
— 2,9
+ 0,3
+ 1,6
— 0,7
— 1,6
— 0,4
— 0,4
— 2,0
1 .0
'-
— 0,63
— 0,063
+ 0,8 ^
The 6 lb. weight
No. 2.
+ 440 gr. Divis.
The five
Avoirdupois Pounds,
Divisions.
Difference
Divisions.
Mean.
DiflFerence
in grains.
— 1,0
3>o
— 1,6
— 1,2
— 0,9
— 2,1
-1,6
— 0,4
— 0,2
— 0^7
— 1»3
— 0,7
— 2,1
1,2
— 0,8
— 0,7
— 1,2
— 1,0
— 0,7
— 0,4
— 0,3 "]
+ 2,3
— 0,5
0,0
+ 0,1
+ 1,4
+ 0,4
— 0,6
— 0,5
+ 0*3 J
>
+ 0,26
+ 0,026
new standards of weights and measures. 25
Deductions from the preceding comparisons. 3 .'iAvl
The mean of the differences of the two 6 lb. weights from
the six troy pounds is - - - — ,0020 grs.
But the sum of the errors of the six troy
pounds is ----- + ,0039
Therefore the mean of the errors of the
two 6 lb. weights is - - - + >ooi9
The first comparisons of the five avoirdupois pounds with
one of the 6 lb. weights + 440 grains gave for the
difference - . - - - - — ,o6so grs.
With the other 6 lb. weight + 440 grains,
the difference was - - - + ,0260
The mean is - - — ,0185
But the mean error of the two 6 lb. weights is +,0019
Therefore the sum of the errors of the five
avoirdupois pounds is ^ ^ - — ,0166
The sum of the differences between No. 1. and the other
avoirdupois pounds being ,019 grains, and all in defect, wires
of the following values were enclosed in each weight ; viz.
In No. 2. - - ,002 grs. *
3. - - ,002
4. - - ,006
5. - - ,007
Total - ,017
MDCCCXXVI. E
/
fS .Yw Captain KaTEr's account of the
The very near agreement of the preceding result with
Mr. Bate's determination, is a sufficient proof of his care,
and. of the accuracy with which the avoirdupois pound has
been obtained.
As each of the avoirdupois pounds had certain wires
enclosed in it when delivered to me by Mr Bate, the folio w-
ingis, an account of the wires they now contain.
No. 1. contains i wire = ,053 grains.
2. — 4 wires = ,184
3. — 4 wires = ,200
^ 4. — Swires = ,250
.ei2 be/do 5. _ not noted.
After the adjustment of the avoirdupois pounds was com-
pleted, Mr. Bate used the large balance to make an approxi-
mate adjustment of the weights of the imperial gallon of
distilled water. This was interrupted by an accident which
rendered it necessary to repair the knife edges of the beam ;
and notwithstanding every care, the balance afterwards
proved less certain in its indications than it was before the
accident. The error arising from this source I have endea-
voured to lessen by increasing the number of comparisons.
Adjustment of the weights of the imperial gallon of water.
These weights were distinguished in the following
manner :
new standards of weights and measures.
That which I shall calif ^^ ^^
No.i.j.
«7
IMP. GALL.
OF WATER AT 62° F
VO:
COF
). 3. \
>. 4. \
wt of
IMP. GALL. " ^'^"'
WATER AT 62° F. a dot after the letter F.
Wt of
IMP. GALL. \ ;
OF WATER AT 62S. J a dot after the figures.
Wt of
IMP. GALL. p,i + i
OF WATER AT 62? F. a dot after the figures,
and another dot after
the letter F.
The two 6 lb. troy weights with 880 grains, making toge-
ther ten pounds avoirdupois, were employed as a standard
in the manner which has been already detailed in describing
the adjustment of the troy pounds. ^^
From previous rough trials, certain wires were added to
each of the gallon weights, the value of which will be given
hereafter, and the following comparisons were made. The
index of the balance varied one division with one-tenth of a
grain. _
The two 6 lb.
weights
+ 880 grains.
Divisions.
Gallon
weights.
■ 1
The two 6 lb.
weights
+ 880 grains.
No. I.
Divisions.
No. 2.
Divisions.
No. 3.
Divisions.
No. 4.
Divisions.
+ 2,5
+ 5,8
-0,6
-0,8
— 0,1
— 3,c
— 3,2
+ 3,9
-6,4
-2,8
— 2,0
+ 2,5
+ 2,7
— 3-3
— 4,1
— 0,2
— 3,3
+ 0,8
-1,5
— 1-7
— 0,9
+ 1.5
-4,9
4-5,4
+ 2,1
— 2,t
-8,1
+ 1,2
-4,1
+ 6,8
+ 4,S
— 1,7
+ ©,4
— 2,5
— 2,2
+ 0,63
+ 0,85
— 1,98
— 0,95
— 1,12
— 0,93
+ Q,»5
+ 0,74
Mean.
?8 Captain Kater's account of the
By the above comparisons, the error of each weight in
parts of a grain is as follows :
No. 1. No. 2. No. 3. No. 4.
— ,272 — ,169 — ,186 — ,167
The two 6 lb.
weights
+ 880 grains.
Divisions.
Gallon weights.
The two 6 lb.
weights
+ 880 grains
Divisions.
No. 1.
Divisions.
No. 2.
Divisions.
No. 3.
Divisions.
No. 4.
Divisions.
— 1,9
+ 3>o
+ 2,9
+ 4,2
+ 1,4
+ 2,5
+ i>3
+ 3>o
-1,9
— 1,0
+ 0,8
+ 2,9
0,0
+ 1,2
+ 2,0
+ +0
— 2,0
-4,9
+ 0,6
— >.7
+ 0,2
+ 1,6
+ 3.1
— 3'2
— 0,6
— 3,3
— 1,9
+ o>S
— 1,8
tl%
+ 0,3
— 1,9
+ 1,0
+ 3'3
+ ».9
-\-Z>9
+ 4,8
+ 4,7
— 1,0
+ »,7
+ 3>4
+ 3.3
+ 2,8
+ 4.1
+ 0,5
+ 5,2
+ 3.4
+ 2,05
+ 3.0S
+ 1,00
— 0,79
— 1,61
+ 2,09
+ 3>o5
+ 2,55
Mean.
By the above comparisons, the error of each weight in
parts of a grain, is as follows :
No. 1. No. 2. No. s. No. 4.
— ,155 — ,334 — ,416 — ,046
The two 61b.
weights
+ 880 grains.
Divisions.
Gallon weights.
The two 6 lb.
weights
+ 880 grains.
Divisions.
No. I.
Divisions.
No. 2.
Divisions.
No. 3.
Divisions.
No.v
Divisions.
+ 4>o
+ 3.5
-5,0
-1,9
+ 2,9
+ 3>7
+ 1,2
+ 3,0
— 1,7
— 0,8
— 4.9
+ 2,2
+ 3,1
_o,4
— 2,6
— 1,6
+ 1,2
+ 2,5
— 1,5
— 3,0
— 3.4
— 0,4 .
— 3»9
+ 6,2
— i,o
— 3.8
+ 0,1
+ 1,1
+ 1.3
+ 7,2
— 0,2
— 0,5
+ 2,7
+ 1,6
+ 3,0
+ 1,20
+ 2,30
— 0,17
— 0,27
— 1,61
+ 0,65
+ 2,30
+ «»75
Mean.
new standards of weights and measures. m^
By the above comparisons the error of each weight in
parts of a grain is as follows :
No. 1. No. 2. No. 3. No. 4.
— ,192 — ,202 — ,336 — ,110
Results of the comparisons of the four weights of the imperial
gallon of water.
No. 1. No. 2. No. 3. No. 4.
Grains. Grains. Grains. Grains.
1st series . . — ,272 — ,169 — ,186 — ,167
2nd series . . — ,155 — ,334 — ,416 — ,046
3d series . . — ,192 —,202 — ,SSQ — ,110
Mean errors . — ,206 — ,235 — ,313 — ,108
A wire equal to its error was now enclosed in each weight.
The numbers and values of the wires inclosed in the gallon
weights are as follow :
Grains.
No. 1 . contains 2 wires, together = 0,366
No. 2. — 4 wires, — = 1,174
No. 3. — 3 wires, — = 0,791
No. 4. — 3 wires, — = 0,422
The adjustment of the gallon weights occupied me till the
10th of April, when the balance was removed to Mr. Bate's
for the purpose of adjusting the standard gallon measures.
Adjustment of the imperial gallon measures.
It has been remarked that the form chosen for the gallon
measure is that of a hollow cone, terminated by a cylindrical
mouth of about an inch and a half diameter. The inside of .
go Captain Kater's account of the
the cone is turned very smooth and close to its base is curved
so as to avoid the acute angle, which would have resulted
from continuing the side of the cone to the bottom. By this
also the advantage was gained of a greater substance for the
insertion of the screws used for attaching the bottom of the
gallon to the cone.
As soldering was thought objectionable, the bottom was
ground to the cone, and it was supposed that it would thus
have been sufficiently secure ; but on letting the gallons
remain filled for 24 hours, in some a slight leakage became
perceptible. After many experiments, the best remedy for
this appeared to be a very minute quantity of fresh grease,
carefully applied to the bottom of the cone and then almost
wholly wiped off; after which the bottom was firmly screwed
in its place.
The following was the method pursued in adjusting the
gallon :
If the gallon contained a considerable quantity, as one or
two hundred grains of water too little, its capacity was
enlarged by turning away a small portion from the flat
bottom. If on the contrary the gallon contained too much,
the base of the cone was ground away ; and it must be evi-
dent that a very small quantity taken from this part would
occasion a considerable variation in the capacity, one thou-
sandth of an inch making a difference of about 17 grains.
Errors of smaller magnitude were removed either by grind-
ing down the top of the mouth, or by enlarging the aperture
by using a cylindrical plug of brass with emery.
The interior of the measure being carefully wiped dry,
it was placed in the scale together with one of the gallon
new standards of weights and measures, si
weights and a circular piece of plate glass ( the use of which
will be presently described), and the whole was counter-
poised, .jj-j^, .
The division at which the index of the balance stood was
noted, and the gallon weight removed ; the gallon was then
nearly filled with distilled water by means of a small glass
syphon, so contrived by Mr. Bate as to prevent the intro-
duction of bubbles of air. The temperature of the water was
then taken as well as the height of the barometer, and the
filling of the gallon continued until the water rose percepti-
bly a little above its mouth. The piece of plate glass before-
mentioned, and which had a small hole drilled in its centre,
was then carefully placed upon the top of the gallon, when
the superabundant water passed through the hole to the upper
surface of the glass, and was removed by drawing it with the
mouth into a capillary glass tube.
The difference of the expansion of water, and of brass,
being an object of the highest importance in the present
operations, I was glad to find that Mr. Bate had made nume-
rous experiments upon this subject, and I had had sufficient
experience of his care to place great reliance upon his con-
clusions. It will be seen that the considerable range of tem-
perature under which the experiments with the gallons
No. 1, 3, and 4, were made, and the uniformity of the results
fully justify this confidence, and form very conclusive evi-
dence of the accuracy of the corrections employed.
But besides the correction for the difference of the expan-
sion of water and of the brass vessel, another allowance is
necessary for the buoyancy of the atmosphere in cases where
extreme accuracy is required. The gallon is to contain ten
32 Captain Kater's account of the
pounds of distilled water, at the temperature of 62° of Fa-
renheit's thermometer, the barometer being at 30 inches ;
consequently, for any difference from this state of the baro-
meter, as well as of the thermometer, a correction must be
applied. Water is 831 times heavier than air when the
barometer is at 30 inches, and the thermometer at 62°, and this
varies directly as the height of the barometer, consequently
the correction due to a difference of one inch of the barometer
will be -5 — X — = -^— part of the weight of water.
831 30 24930 r &
The gallon weight being counterpoised with brass, and
brass being about 8 times heavier than water, the effect of
the buoyancy of the atmosphere upon brass will be only ^
of that upon water, and this will tend to lessen the effect
upon the water by one eighth part of the whole quantity.
Therefore — -— ^ I x 70000 grains = 2,46 grains, is the
number of grains by which the weight of the gallon of water
will be increased by a depression of one inch of the barometer.
Though the variation of the temperature of the air during
the experiments was several degrees, the effect upon the
correction for the buoyancy of the atmosphere would have
been so inconsiderable as to be unworthy of notice upon the
present occasion.
As an error of one degree in the determination of the
temperature of the water contained by the gallon would
occasion an error ranging from four to six grains, it must
be evident that a knowledge of the precise temperature of the
Wjater was of primary importance. For this purpose a thermo-
meter was used which had been prepared with extraordinary
care by Mr. Bate, and the scale was such that its indications
were estimated without difficulty to tenths of a degree.
new standards of weights and measures. 33
It would perhaps be useless to detail the numerous expe-
riments which were made in approximating to the final
adjustment of the gallon measures, and I shall therefore
immediately proceed to state the ultimate results.
Gallon (which I shall designate) No. 1.
Date.
Barom.
Temp,
of the
Water.
Weight of
water con-
tained bythe
gallon,
lolbs. ±
Correction
for
Barometer.
Correction
for
Temperat.
Weight of
water the
gallon
should have
contained.
10 lbs. ±
Error
ingrains.
June.
I
6
II
«5
Inches.
30,29
29,94
30,22
30,16
30,27
0
59>o
59,4
66,6
67,8
67,2
Grains.
+ 13,13
+ 11,14
— 24,96
— 30,84
— 27,21
Grains.
— 0,71
+ 0,15
— 0,54
— 0,40
— 0,66
Grains.
+ 12,38
+ 10,83
— 23,29
— 30,17
— 26,68
Grains.
+ 11,67
+ 10,98
— 23,83
— 30,57
— 27,34
+ 1,46
+ 0,16
— 1,13
— 0,27
+ 0,13
Mr. Bate.
Mr. Bate.
Mr. Bate.
Mean
-1-0,07
The bottom of the gallon No. 2. was rather thin, it was
therefore subsequently adjusted by Mr. Bate, and sentto'the
Exchequer to be used on more ordinary occasions.
Gallon No. 3.
Weight of
Temp.
Weight of
water con-
Correction
Correction
water the
Error
Date.
Barom.
of the
Water.
tained bythe
gallon.
10 lbs. ±
for
Barometer.
„ ^°^ ^ should have
Temperat. contained.
10 lbs. ±
m grains.
May.
Inches.
0
Grains.
Grains.
Grains. 1 Grains.
18
30,33
57.9
+ 16,52
— 0,81
+ 16,34 + 15,53
+ 0,99
20
30,29
57.4
+ 18,48
— 0,71
+ 18,02
+ 17,31
+ 1,17
23
29,96
60,5
+ 6,67
+ 0,10
+ 6,44
+ 6,54
+ 0,13
31
30,30
59.0
+ 12,58
— 0,74
+ 12,38
+ 11,64
+ 0,94
Mr. Bate.
June
30,30
59,2
+ 9,78
— 0,74
+ 11,60 j+ 10,86
— 1.08
Mr. Bate.
I
30,30
58,8
+ 12,72
— 0,74
-f- 13,10 ;-|- 12,36
+ 0,36
II
30,18
67.3
— 31.53
— 0,45
- 27,26
— 27,71
- 3,82
Mr. Bate.
>3
30,14
67,4
— 26,74
— 0,35
~ 27,84
— 28,19
+ 1.45
30,14
68,2
— 31,80
— 0,35
- 32.54
— 32.89
+ 1.09
Mean
+ 0,14
MDCCCXXVI.
34
Captain Kater*s account of the
Gallon No. 4.
Date,
Barom.
Temp,
of the
Water.
Weight of
water con-
tained bythe
gallon,
lolbs.
Correction
for
Barometer.
Correction
for
Temperat.
Weight of
water the
gallon
should have
contained
10 lbs. d
Error
in grains.
June.
6
8
II
13
H
Inches.
29,94
29'95
30,22
30,16
30,14
30,28
30,25
59*2
61,7
66,9
68,2
67,0
68,8
67*9
Grains.
+ 12,36
+ 2,36
^ 19,69
— 28,58
— 25,30
— 36,42
30>84
Grains.
+ 0,15
+ 0,12
— o>54
— 0,40
— 0,35
— 0,69
— 0,61
Grains.
-\- 11,60
+ 1,31
- 24,96
- 32,54
- 25,52
- 36,17
- 30.75
Grains.
+ »i.75
+ 1,43
— 25,50
— 32,94
— 25,87
— 36,86
-- 31,36
+ 0,61
+ Q>93
+ 5.81
+ 4,36
+ 0,57
+ 0,44
+ 0,52
Mr. Bate.
Mr. Bate.
Mr. Bate.
Mean
Mean, rejecting greatest and least
+ 1,89
+ 0,61
Gallon No. 5.
Date.
Barom.
Temp,
of the
Water.
Weight of
water con-
tained bythc
gallon.
iolbs.+
Correction
for
Barom^er.
Correction
for
Tempeiat.
Weight of
water the
gallon
should have
contained.
lolbs. +
Error
in grains.
■
June.
1
3
8
Inches.
30,30
30,27
29,70
29,95
0
58.7
60,25
60,6
61,4
Grains.
+ 12,83
+ 5>8o
+ 7.9'
+ 2,80
Grains.
— 0,74
— 0,66
+ 0,74
+ 0,12
Grains.
+ 13,47
+ 7,47
-1- 6,02
H- 2,63
Grains.
+ 12,73
+ 6,81
+ 6,76
+ 2,75
+ 0,10
— 1,01
+ i»i5
+ 0,05
Mr. Bate.
Mean
+ 0,07
Adjustment of the Qiiart and Pint for the Exchequer.
The quart and pint measures for the Exchequer differed
in no respect from the gallon, except in being of inferior
dimensions, and were adjusted in a similar manner.
new standards of weights and measures*
. 55
Quart.
Date.
Barom.
Temp,
of the
Water.
Weight of
water con-
tained bythe
quart.
2I lbs. ±
Correction
for
Barometer.
Correction
for
Temperat.
Weight of
water the
Quart
should have
contained.
z\ lbs. ±
Error
in grains.
June.
J5
Inches.
30,27
30,27
30,27
0
69,0
67,1
67,5
68,1
Grains.
— 9'82
— 6,98
— 6,86
— 8,12
Grains.
— 0,16
— 0,16
— 0,16
— 0,16
Grains.
— 9'34
— 6,52
— 7."
— 7,98
Grains.
— 9,50
— 6,68
— 8,14
— 0,32
— 0,30
+ 0,41
+ 0,02
Mean
— 0,05
Pint.
Date.
Barom.
Temp.
of the
Water.
Weight of
water
contained
by the pint.
1 4 lbs. ±
Correction
for
Barometer.
Correction
for
Temperat.
Weight of
water the
pint should
have con-
tained.
li lbs. ±
Error
in grains.
June.
18
Inches.
30,27
30,18
30,18
67,6
63,0
63,4
Grains.
— 3,63
— 0,53
— 0,70
Grains.
— 0,08
^ 0,05
— 0,05
Grains.
— 3,55
— 0,58
— 0,82
Grains.
— 3'63
— 0,63
— 0,87
0,00
+ 0,10
+ 0,17
^ Mean
+ 0,09
Verification of the Bushel measures.
The weight of the bushel measure, together with the
80 lbs. of water it should contain, was about 250 lbs. and as
I could find no balance capable of determining so large a
weight with sufficient accuracy, I was under the necessity of
constructing one for this express purpose.
36 Captain Kater*s account of the
I first tried cast iron ; but though the beam was made as
light as was consistent with the requisite degree of strength,
the inertia of such a mass appeared to be so considerable,
that much time must have been lost before the balance would
have answered to the small differences I wished to ascertain.
Lightness was a property essentially necessary, and bulk
was very desirable in order to preclude such errors as might
arise from the beam being partially affected by sudden alte-
rations of temperature. I therefore determined to employ
wood, a material in which the requisites I sought were com-
bined. The beam was made of a plank of mahogany about
70 inches long, 22 inches wide, and 2^ thick, tapering from
the middle to the extremities. An opening was cut in the
centre, and strong blocks screwed to each side of the plank
to form a bearing for the back of a knife edge which passed
through the centre. Blocks were also screwed to each side
at the extremities of the beam on which rested the backs of
the knife edges for supporting the pans. The opening in
the centre was made sufficiently large to admit the support
hereafter to be described, upon which the knife edge rested.
In all beams which I have seen, with the exception of those
made by Mr. Robinson, the whole weight is sustained by
short portions at the extremities of the knife edge, and the
weight being thus thrown upon a few points, the knife edge
becomes more liable to change its figure and to suffer injury.
To remedy this defect, the central knife edge of the beam
I am describing was made six inches, and the two others five
inches long. They were triangular prisms with equal sides,
of three quarters of an inch, very carefully finished, and the
edges ultimately formed to an angle of 120°.
new standards of weights and measures, si
Each knife edge was screwed to a thick plate of brass, the
surfaces in contact having been previously ground together,
and these plates were screwed to the beam, the knife edges
being placed in the same plane, and as nearly equidistant and
parallel to each other as could be done by construction.
The support upon which the central knife edge rested
throughout its whole length was formed of a plate of polished
hard steel screwed to a block of cast iron. This block was
passed through the opening before-mentioned in the centre
of the beam and properly attached to a frame of cast iron.
The stirrups to which the scales were hooked rested upon
plates of polished steel to which they were attached, and the
under surfaces of which were formed by careful grinding
into cylindrical segments. These were in contact with the
knife edges their whole length, and were known to be in
their proper position by the correspondence of their extremi-
ties with those of the knife edges.
.A well-imagined contrivance was applied by Mr. Bate for
raising the beam when loaded, in order to prevent unneces-
sary wear of the knife edge ; and for the purpose of adjusting
the place of the centre of gravity, when the beam was loaded
with the weight required to be determined, a screw carrying
a moveable ball projected vertically from the middle of the
beam.
The performance of this balance fully equalled my expec-
tations. With two hundred and fifty pounds in each scale,
the addition of a single grain occasioned an immediate varia-
tion in the index of one-twentieth of an inch, the radius being
fifty inches.
In using this beam, care should be taken that the ends of
38 Captaifi Kater's account of the
the steel plates to which the stirrups are attached coincide
with the ends of the knife edges, otherwise some error
might arise from a possible want of parallelism.
The bushel measure being placed in one of the scales,
together with 80 lbs. * the whole was counterpoised with
brass ; the 80 lbs. was then removed, and the bushel filled
with water by means of a syphon. The temperature of the
water was then very carefully taken, and the height of the
barometer registered. A circular piece of plate glass, as
plane as could be procured, having a hole about a quarter of
an inch diameter in its centre, was slid over the bushel, and
the air-bubbles which appeared on the under surface of the
glass were removed by touching them with a^ small bent
tube made of flexible metal, a method thought of by
Mr. Bate. Water was added through the hole in the glass ;
and by carefully observing the curvature of the fluid surface,
it was soon evident that the filling of the bushel might be
repeated without a greater difference than three or four
grains.
It is scarcely requisite to remark that many experiments
were made, not here detailed, before the adjustment of the
bushel was perfected ; the very great accuracy and masterly
workmanship however of Mr. Keir, who had been furnished
with gauges for the diameter and depth of the bushel, ren-
dered little alteration necessary.
* This was obtained by taking twice the weight of the four weights of the
gallon of water.
new standards of weights and measures.
Bushel No. i.
3^
Date.
Barom.
Temp,
of the
Water.
Weight of
water con-
tained by
the bushel,
80 lbs. ±
Correction
for
Barometer.
Correction
for
Temperat.
Weight of
water the
bushel
should have
contained.
80 lbs. ±
Error
ingrains.
June.
22
24
Inches.
30,00
29,98
29,96
60,30
61, 4
6i,75
Grains.
+ 61,10
+ 34,40
+ i2»5S
Grains.
O, O
+ 0,40
+ 0,10
Grains.
+ 58,13
+ 21,01
+ 8»75
Grains.
+ 58,13
+ 21,41
+ 8,85
+ 2,97
+ 12,99
+ 3»7o
Mr. Bate,
Mean
+ 6,55
Bushel No. 2.
Date.
Barom.
Temp,
of the
Water.
Weight of
water con-
tained by
the bushel.
80 lbs. ±
Correction
for
Barometer.
Correction
for
Temperat.
Weight of
water the
bushel
should have
contained.
80 lbs. ±
Error
in grains.
July.
7
8
Inches.
30,00
29,98
29,98
0
63,1
62,5
62,6
Grains.
— 38,00
— 18,10
— 19,59
Grains.
0,00
+ 0,40
+ 0,40
Grains.
— 41,00
— 18,49
— 22,19
Grains.
— 41,00
— 18,09
— 21,79
+ 3,00
— 0,01
+ 2,20
Mean
+ 1,73
Bushel No. 3.
Date.
Barom.
Temp,
of the
Water.
Weight of
water con-
tained by
the bushel.
80 lbs. ±
Correction
for
Barometer.
Correction
for
Temperat.
Weight of
water the
bushel
should have
contained.
80 lbs. ±
Error
ingrains.
May.
18
20
24
31
J|»ne,
»7
Inches.
30,33
30,29
29,83
30,28
30,16
0
57»4
62,3
59*3
66,8
Grains.
+ 141,65
+ 140,54
+ »»54
+ 96,20
— 201,50
Grains.
— 6,48
— 5.68
+ 3*36
— 5>52
— 3,20
Grains.
+ I44>l6
+ 1 36,06
— 11,09
+ 89,73
~'95>25
Grains.
+ i37>68
+ 130,38
— 7.73
+ 84,21
— 198,45
+ 3.97
+ 10,16
+ 9,27
+ 1 1,99
— 3,05
Mr. Bate.
Mr. Bate.
Mr. Bate.
Mean
+ 6,47
40
Captain Kater's account of the
Bushel No. 4.
Date.
Barom.
Temp,
of the
Water.
Weight of
water con-
tained by
the bushel.
80 lbs. ±
Correction
for
Barometer.
Correction
for
Temperat.
Weight of
water the
bushel
should have
contained.
80 lbs. ±
Error
in grains.
June.
27
Inches.
29,77
29^77
29,79
0
6i,9
62,0
61,9
Grains.
+ 6,10
+ 5>6o
+ 5»2o
Grains.
+ 4.48
+ 4*48
+ 4.16
Grains.
+ 3,50
0,0
+ 3>5o
Grains.
+ 7.98
+ 4,48
+ 7>66
-1,88
+ 1,12
— 2,46
Mean — 1,07
In order to enable the reader to form some idea of the
errors of the measures of capacity, it may be remarked that
a drop of water is commonly estimated to be nearly equal to
one grain.
As the quantity of water contained by the bushel measure
is determined by the surface of the glass plate, which should
be a perfect plane, a figure not easily attainable, it is not to
be understood that the capacity of the bushel is true within
the limits of the errors above-mentioned, but to the gallon,
quart, and pint measures, in consequence of their more ad-
vantageous form, this source of error does not in any sensible
degree apply.
Verification of the standard yards with steel terminations.
These standard yards were made by Mr. Dollond ; they
are of brass, one inch square. To their extremities are firmly
screwed rectangular pieces of steel of the same width as the
bar, and projecting above its surface. The distance between
the interior faces of the steel termination is intended to be
equal to the length of the imperial standard yard.
new standards of weights and measures. 41
To determine this distance I employed the following
method :
Two bars of brass were prepared, three quarters of an inch
square and rather less than 18 inches long. They were ter-
minated by planes at right angles to their length ; and upon
the upper face of each bar, very near to the end, a fine trans-
verse line was drawn ; the other ends of the bars being then
placed in contact and kept so by springs, the distance between
the lines was taken by means of two micrometer microscopes
fixed to a bar of wood and referred to Sir G. Shuckburgh's
standard scale, which scale, it has already been remarked,
does not sensibly differ from the imperial standard yard.
The distance between the lines was found by numerous
comparisons to be 919 divisions of the micrometer less than
the standard yard, each division of the micrometer being
equal to — ^ of an inch.
^ 23363
The brass bars were then placed upon the standard to be
examined, their marked ends being next each other, and
their opposite extremities kept in contact with the steel faces
by a spring introduced between the bars, a part below the
surface being cut away for that purpose. The distance
between the lines was then measured by the micrometer
microscope, which distance, had the standard been perfectly
correct, would have been equal to what the distance of the
lines in the former position of the bars wanted of s^ inches.
Standard Yard, No. 1.
The distance between the lines upon the brass bars was
found by the mean of six measurements to be 918,2 divisions
Df the micrometer, which differs so little from 919 divisions,
MDCCCXXVI. G
4# Captain Kater's account of the
that this standard yard may be considered as perfectly
correct.
Standard Yard, No. 2.
The mean of sixteen measurements gave the distance
between the lines upon the brass bars 910 divisions. This
standard is therefore 9 divisions, or ,00038 of an inch too
shortw
Standard Yard, No. 3.
By the mean of six measurements this standard appeared
to be five divisions, or ,00021 of an inch too long.
Standard Yard, No. 4.
The mean of ten measurements gave the error of this
standard five divisions, or ,00021 of an inch too short.
Adjustment of the Standard Tards with gold points.
The standard yards last described are intended merely for
the purpose of sizing those employed in commerce, and the
trifling differences above stated may be utterly disregarded ;
but the Commissioners of Weights and Measures thought it
desirable that accurate copies of the imperial standard yard
should be made, to be carefully preserved and transmitted to
posterity solely for the purpose of being referred to upon
extraordinary occasions, or upon questions important to
science.
The difficulty of transferring a given distance from one
scale to another, is well known to all who are acquainted
with the subject ; the operation is one of considerable deli-
cacy ; and notwithstanding every precaution, is seldom abso-
nezv standards of weights and measures, 43
lutely free from error. But a national standard should be
accurately that which it professes to be. It is not enough to
determine its error, as the record of this may in process of
time be lost ; it therefore became necessary to devise a
method by which any perceptible error in those standards
which are the foundation of all the others, might ultimately
be annihilated.
The four standard yards which I am about to describe are
of brass, one inch and a quarter wide, and half an inch thick.
This thickness is the same as that of Sir G. Shuckburgh's
scale, and was chosen in order that both might be affected
with equal readiness by any change of temperature ; for as
the imperial standard yard of 1760 is one inch square, I
thought it preferable to adjust the new standards by means
of Sir G. Shuckburgh's scale, which, as I have before re-
marked, does not sensibly differ from it.
A disk of gold being let into the surface near one extre-
mity, a hole was drilled through the bar at the distance of
thirty-six inches from the centre of the disk, and being made
slightly conical, a plug of brass was ground in the hole so
as to fit it perfectly. A gold disk was let into the top of the
plug, and reduced to a level with the surface of the scale.
The other end of the plug projected beneath the scale, and
had a small hole through it to admit a wire, by means of
which it might be turned round. A very fine deep dot was
then made by Mr. Dollond upon each of the gold disks, as
nearly as it could be done at the distance of thirty-six inches
from each other, the dot upon the moveable disk not being
exactly in its centre.
44 Captain Kater's account of the
Before the plug was ground in its place a small hole was
drilled through the side of the scale into the conical
aperture.
The microscopical apparatus employed on the present
occasion has been described in the paper upon the comparison
of various British standards of linear measure before quoted.
The cross wires of the microscopes being brought respec-
tively over zero, and s6 inches upon Sir G. Shuckburgh's
scale, the apparatus was transferred to the new standard, and
the intersection of the cross wires of one of the microscopes
placed upon the centre of the fixed dot. The moveable dot
was then brought by turning the brass plug to the intersec-
tion of the cross wires of the other microscope.
The distance of the dots was repeatedly compared with
Sir G. Shuckburgh's standard upon different days, in order
to ascertain that no perceptible error remained. A drill was
passed through the hole in the side of the scale, and the
brass plug carefully pierced through ; a pin was then driven
into the plug so as to render any change of position impossi-
ble, and the projecting part of the plug was cut off.
The standards being thus finished, they were again com-
pared with Sir G. Shuckburgh's scale, and it was with
surprise and disappointment that I found the whole of them
apparently too short. They had been adjusted upon a board
of mahogany carefully planed, and the table upon which they
were now placed was so flat as to occasion little alteration in
a spirit level passed along it. The error of the standards
was however far too considerable to be attributed to any
curvature which on this occasion could take place, and it was
new standards of weights and measures. 45
hot until after several days that I discovered the cause of
this perplexing circumstance. I found that by placing a card,
the thickness of which w^as accurately one-fiftieth of an inch,
under the middle of the standard, the distance of the dots
was much increased, and by placing a card of the same
thickness under each of the extremities, and withdrawing
that which was under the centre, the distance of the dotsi
was considerably diminished. The total difference amounted
to no less than ,0016 of an inch, whilst the double of the
error which would have arisen from mere curvature under
similar circumstances would not have been one ten-thou-
sandth of an inch.
The cause was now evident ; by elevating the middle of
the standard, the under surface was shortened, and the upper
surface extended ; and on the contrary, when the extremities
were elevated the upper surface was compressed and the
lower surface lengthened ; the quantity of the effect evidently
depending upon the thickness of the bar.
Having thus assured myself of the source of the error,
a method of obviating it soon presented itself. As the upper
and under surfaces of the bar are in different states, the one
being compressed and the other extended, there must be an
intermediate plane which suffers neither extension nor com-
pression, and this plane must be nearly midway between the
two surfaces. I therefore caused Mr. Dollond to reduce
the thickness of the bar for the distance of an inch and three
quarters from its extremities to one half ; the gold disks and
plugs were then inserted as before, and the adjustment
completed in the manner which has been described. The
plugs being secured, and the projecting parts removed, the
4Q Captain Kater's account of the
standards were repeatedly compared with Sir G. Shuck-
burgh's scale (the standard being placed upon the scale)
when no perceptible difference could be detected. Pieces of
card were now placed under the standard as before, without
occasioning any appreciable alteration ; and I had thus expe-
rimental proof of the perfect efficiency of the remedy I had
employed.
I have been thus particular in detailing the difficulties I
experienced, because they exhibit a source of very consider-
able error which may arise from the thickness of a standard
scale, and which I believe has never before been suspected.
It may be here not unnecessary to remark, that on every
occasion on which I have used Sir G. Shuckburgh's scale, it
has fortunately been placed not only upon the same table,
but upon the same part of it.
The various standards which have been described in this
paper with the exception of the yards with steel termina-
tions are not meant for common use, but are intended to be
carefully preserved, to be referred to only upon extraordi-
nary occasions. In addition however to these, other weights
as well as measures of capacity were made with great care by
Mr. Bate. The following is a list of the whole, with an
account of the places where they are deposited.
Standards deposited at the Exchequer ^ Westminster.
1 Imperial standard yard with gold points.
I Standard yard with steel terminations. No. i.
1 Imperial troy pound. No. 5.
X Avoirdupois pound. No. 1.
new standards of weights and measures. 47
1 Avoirdupois pound, No. 5. (in a box with smaller
weights.)
1 Weight of imperial gallon of water, No. 1.
1 Imperial gallon measure, No. 3.
1 Bushel, No. 3.
1 Quart, No. 4.
1 Pint.
A copy of the imperial Gallon,
Quart, and
Pint.
Bushel,
Half bushel.
Peck,
Gallon,
Half gallon.
Quart,
Pint,
Half pint.
Gill,
Half gill.
Set of avoirdupois weights, from 56 lbs. to half a drachm.
Set of counterpoises for the above set of weights.
1 Set of troy weights, from one pound to one grain, with
counterpoises.
1
for common use.
)> cylindrical, for common use.
Standards deposited at Guildhally London.
1 Imperial standard yard with gold p(»nts.
1 Standard yard with steel terminations. No. 4.
1 Imperial troy pound. No. 1.
1 Avoirdupois pound. No. s.
48 Captain Kater's account of the
1 Weight of imperial gallon of water, No. 3.
1 Imperial gallon measure, No. 5.
1 Bushel, No. 4.
1 Quart.
1 Pint.
1 Set of avoirdupois weights, from 56 lbs. to half a drachm.
Standards deposited at Edinburgh.
1 Imperial standard yard with gold points.
1 Standard yard with steel terminations. No. 2.
1 Imperial troy pound. No. 2.
1 Avoirdupois pound. No. 3.
1 Weight of imperial gallon of water. No. 4*
1 Imperial gallon measure, No. 4.
1 Bushel, No. 1.
1 Quart.
1 Pint.
I Set of avoirdupois weights, from 56 lbs. to half a drachm.
Standards deposited at Dublin.
1 Imperial standard yard with gold points.
1 Standard yard with steel terminations, No. 3.
1 Imperial troy pound. No. 4.
1 Avoirdupois pound. No. 4.
1 Weight of imperial gallon of water, No. 2,
1 Imperial gallon measure. No. 1 .
1 Bushel, No. s.
1 Quart.
1 Pint.
1 Set of avoirdupois weights, from 56lbs. to half a drachm.
new standards of weights and measures. 49
I cannot conclude without bearing testimony to the un-
wearied perseverance, ability and accuracy, which Mr. Bate
has shown in the course of a work attended with no common
difficulties, and to the perfect execution of which he has
devoted, for a long period, the whole of his time and
attention.
From what has been said, it will be seen that the length
of the pendulum vibrating seconds in London has been found
in parts of the imperial standard yard ; consequently, the
value of the yard may at any time be known, having been
referred to a natural standard presumed to be unalter-
able. The length of the French metre, a standard expressing
a certain portion of a terrestrial meridian, has also been
given in parts of the English scale. The weight of a cubic
inch of distilled water has been determined in parts of the
imperial troy pound ; and thus the pound, if lost, may at any
future age be recovered. The avoirdupois pound is now for
the first time defined, and the measures of capacity are made
to depend upon the weight of water they contain ; the impe-
rial gallon, containing ten pounds avoirdupois of water,
having been declared to be the unit or only standard measure
of capacity from which all others are to be derived. This
it is to be presumed cannot but powerfully tend to produce
uniformity throughout the United Kingdom, by putting it in
the power of every individual possessed of standard weights,
to verify his measures of capacity with the utmost facility.
London, November, 1825.
MDCCCXXVI. H
40
Captain Kater's account of the
APPENDIX.
Table of the correction on account of temperature to he applied
to the contents of the Gallon.
Temperat.
Fahrenheit.
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
Grains.
+ 35,454
+ 33,972
+ 32,214
+ 30,181
+ 27,877
+ 25,304
+ 22,464
+ 19,362
+
+
+
+
15,999
12,379
8,504
4,376
0,000
— 4,623
— 9,489
— 14,596
— 19,942
— 25,522
— 31,335
— 37,377
— 43,646
Difference
fori**
1,481
1,758
2,033
2,304
2,573
2,839
3,102
3,363
3,620
3,875
4,127
4,376
4,623
4,866
5,107
5,345
5,580
5,813
6,042
6,269
new standards of weights and measures, 51'
POSTSCRIPT.
Since the preceding Paper was read, I have received a
work on Astronomy, published at Tubingen in 18 n, by
Professor Bohnenberger. This work had been pointed out
to me by Professor Schumacher as containing a description
of the convertible pendulum, and a suggestion of its employ-
ment for the purpose of determining the distance between
the centres of suspension and oscillation.
A friend has favoured me with a translation of the part irt
question, by which I find M. Schumacher's information to
be perfectly correct, and that the conception of the converti-
ble pendulum is not so new as I had imagined when I first
engaged in this enquiry. After demonstrating the recipro-
city of the centres of suspension and oscillation, the author
proceeds to say : ** On a cylindrical or prismatic rod C A
" (fig. 102.) let there be placed two wedge-formed axes
** at C and c, whose edges being turned towards each other,
" are perpendicular to the rod and parallel to each other.
" Let the one be at the end C of the rod, and the other at c,
" distant from C something more than two-thirds the length
" of the rod, so that the centre of oscillation 0, about the
" edge C, may fall between C and c. On the remaining
" part, cA of the rod, let a small weight n, slide backwards
" and forwards. Now, by a diminution of the mass of the
** rod on one or on the other side, it is easy to manage, that
" if this pendulum be suspended on its edge C, a plumb line
" hanging down from this, falls upon the edge c, conse-
" quently the centre of gravity of the pendulum falls in the
** plane of the axis of rotation. By sliding the weight n, the
52 Captain Kater's account^ &c.
" centre of oscillation round C may be made to fall in c,
" which is known by the oscillations on C and c being
" isochronous. Therefore the distance of the edges is equal
" to the length of the simple pendulum which is isochronous
" with this compound pendulum/'
Although it does not appear that this idea was ever put in
practice, it is evident, from the above extract, that the first
proposal to determine the length of the seconds pendulum
by means of the convertible pendulum, belongs to Professor .
BoHNENBERGER, and I take the earliest opportunity of ac-
knowledging his claims, in order that the credit of the iirsj:
suggestion may re^tjwh^re it J5 so justly due. " ,.
|>}p4oa, 3 1 6ji Deceaabejr,j iSf j.
■' ' ' ■ : '! oi:ria)
■Ho f[:
c 5s:i
II. Description of an improved Hygrometer. By Mr. Thomas
Jones. Communicated by Captain Henry Kater, F. R. S.
Read June 16, 1825.
___ •
Xhe attention of the scientific world has been lately so
much occupied in experiments on atmospheric phenomena,
that it is hoped any simplification or improvement in the
instruments emplojed for that purpose, may not be unac-
ceptable.
The principle of the hygrometer which I am about to
describe, is that of enabling the observer, readily and accu-
rately, to ascertain by direct and simple means, the degree of
temperature at which the moisture of the atmosphere is con-
densed, and the instant at which that operation commences.
The hygrometer is composed of a mercurial thermometer,
the graduated scale of which is about four inches and a half
long ; at the lower part of the scale the glass tube is bent
to form a right angle, at the end of which the bulb of the
thermometer rises parallel to the scale, and about one inch
from it ; the bulb is about one inch long, and of a cylindrical
form, with a black convex top, the diameter of which is a little
more than that of the cylindrical part, which is covered with
silk. The scale is attached to a piece of cylindrical wire,
three inches long, and turns upon a joint screw passing into
its edge, the other end of which wire being placed in a
tubular foot fixed to the inside of one end of the case, forms
54 Mr. Jones's description of an improved hygrometer.
SL Stand for the instrument. The case contains a small bottle
for ether.
The thermometer thus constructed, will give both the tem-
perature of the air and that of the dew point ; which last is
effected by placing the mouth of the bottle containing the
ether, in contact with the upper part of the covered surface
of the bulb, when by gently inclining the bottle, the ether
will flow downwards without wetting the top of the bulb,
which will almost immediately become dull by the deposition
of moisture on its surface ; when the observed temperature
may be taken and the difference ascertained.
Should it be objected against the principle of the instru-
ment here proposed, that the indications do not exhibit the
true temperature of the upper surface of the bulb on which
the deposition of dew takes place, but that of the lower part
to which the ether is applied ; it may be answered, that by
inclining the whole instrument so as to render the axis of the
bulb horizontal, and establish thereby a free circulation of
the mercury in every part, this objection may be obviated ;
but on repeated trials I have not found this to produce any
difference in the results.
I ought also perhaps to mention that an instrument some-
what similar in principle has been used in Vienna, and was
mentioned by Professor Baumgarten of that capital to a
friend, who communicated the fact to myself.
The instrument is represented in Plate I. Fig. i .
THOMAS JONES.
20th February, 1825.
mil. Trans. MDCCCXXVI. PlaU \.p.S4.
iM. (Sajcie jc
i: 5s3
III. Observations on the changes which have taken place in some
antient alloys of copper. By John Davy, M. D. F. R. S. In
a Letter to Sir Humphry Davy, Bart. Pres. R. S.
Read November 17, 1825.
Permit me through you to lay before the Royal Society,
the results of some experiments and observations on the
incrustations of certain antient alloys of copper, which I trust
may not be undeserving of notice, whether considered in
connexion with the arts of Antient Greece, or in relation to
the slow play of chemical affinities acting during a long^
period of time.
I shall commence with the most interesting object that
I have examined since I have been in the Mediterranean, for
which I am indebted to His Excellency Sir Frederick Adam,
His Majesty's Lord High Commissioner in the Ionian islands.
This is a bronze helmet of the antique Grecian form, recently
found in a shallow part of the sea, between the citadel of
Corfu, and the village of Castrades. Both internally and
externally it is partially encrusted with shells, and a deposit
of carbonate of lime. The surface of the helmet generally,
both under the incrustation, and where freed from it, is of a
variegated colour, mottled with spots of green, dirty white,
and red. On minute inspection, the green and red patches
exhibit a crystalline structure, and the red very distinctly ;
and on examining them with a lens, they were found to be
56 Dr. Davy'5 observations on the changes which have
formed of octohedrons of the red oxide of copper, intermixed
with crystals of the same form of metallic copper. These
crystals are most distinct at the surface ; they even adhere
to the calcareous crust, and may be detached with it, pre-
senting well- formed facets towards the part from which they
have been separated. Chemical examination shows that
they are actually composed of metallic copper, without the
least tarnish, and of the pure ruby protoxide of copper ; and
that the green rust consists principally of carbonate and sub-
muriate of copper, and the dirty white chiefly of oxide of
tin. The mineralizing process (if I may be allowed the
expression) which has produced these new combinations, in
general has penetrated very little into the substance of the
helmet. The incrustation and rust removed, the metal is
found bright beneath ; in some places considerably corroded,
in others very slightly. It proves on analysis to be copper
alloyed with 18.5 per cent, of tin. Its colour is that of our
common brass, and it possesses a considerable degree of
flexibility.
An antient nail from a tomb in Ithaca, and an antient
mirror from a tomb at Samos, in Cephalonia, have afforded
me results very similar to the preceding, excepting that the
mineralized part, consisting of oxide of tin, submuriate,
carbonate, and protoxide of copper, each more or less col-
lected apart from the others into little masses, has exhibited
rather a crystalline structure than distinct well-formed
crystals, and has been without any appearance of crystals of
metallic copper. The copper in the mirror I have found
alloyed with about 6 per cent, of tin, and a very minute
quantity of arsenic and zinc.
taken place in some antient alloys of copper. 57
I have examined a select number of antient coins, pur-
posely chosen from the fine collection of Dr. Demetrio
Petrizzopulo, of Santa Maura, to whose kindness I am
indebted for them. The results too which they have afforded
are in conformity with the preceding. As this part of my
subject may be interesting to the antiquarian, as well as to
the chemical enquirer, I shall treat it a little in detail. The
very pale incrustations, consisting of a mixture of green and
white particles, contain a large proportion of oxide of tin,
and a little carbonate of copper, or submuriate of copper, or
both. They appear to owe their light hue to the accumula-
tion of the oxide of tin at the surface. The black incrusta-
tions owe their colour to the predominance of the black oxide
of copper, which is commonly mixed with a little protoxide
of the same metal, and a minute quantity of oxide of tin,
and of the carbonate and submuriate of copper. The coins
that I have examined with this crust have contained very
little tin. The bluish-green incrustations consist chiefly of
carbonate of copper, either without oxide of tin, or mixed
with a small proportion of this metal. The emerald-green
incrustations abound in the submuriate of copper, and the
red consist almost entirely of the protoxide of copper. These
two compounds I have never witnessed spread over the
whole of a coin, but more or less mixed with rusts of a
different kind, studding the surface in the form of little
crystalline elevations.
It is natural to enquire — is there any connexion between
the chemical composition of the incrustations of antient coins,
and their texture ; some being remarkably smooth, and as
MDCCCXXVI. I
58 Dr. Davy's observations on the changes which have
it were polished, preserving admirably the original impression
of the die ; whilst others are rough and deformed ? I am
disposed to reply in the negative, not having yet discovered
such a connexion ; excepting thus far, that the protoxide of
copper, and its submuriate, frequently appear in minute
crystalline elevations rising above the surface of the coin.
Generally, I suspect the difference of texture in question
depends on other circumstances, and very likely in different
degrees of rapidity of operation of the mineralizing cause.
It is a curious question for consideration, the manner in
which the crystalHne structure is acquired exhibited by these
incrustations ; and still more so, how crystals are formed,
especially such as were discovered on the helmet, and on the
adhering calcareous deposit. There being no reason to sup-
pose deposition from solution, are we not under the necessity
of inferring, that the mineralizing process witnessed in its
effects, depends on a slow motion and separation of the
particles of the original compound ? and, must we not con-
clude, that this motion is connected with the operation of
electrochemical powers ?* Supposing the oxides first formed
upon the bronze in a state of negative electricity, with respect
to the metal, their agency, in a long course of ages would
be to separate the least oxidable metal, the copper, in its
pure form ; and all the changes are such as may be accounted
for from agencies of the same kind, but of different intensity.
And may not similar explanations be given of other like
* The separation of the copper from the tin in the bronzes found in the ancient
cities destroyed by volcanic eruptions, must be referred to another source ; namely,
the crystallizations dependent upon degrees of heat a little below the point of fusion
of the alloy.
taken place in some antient alloys of copper. 59
phasnomena, which often seem to» occur in the mineral
kingdom ? These facts offer an obvious practical application,
both in determining the antiquity and genuineness of ancient
works of art ; for aerugo of the kind which I have described
could not be successfully imitated by any artificial processes ;
and a very slight chemical examination, or even one by the
lens, would be sufficient to expose any fraud attempted to be
practised by substituting modem imitations for ancient
works.
I am, most truly yours,
J. DAVY.
To Sir H. Davy, Bart,
Pres. R. S.
ceo 3
IV. Additional proofs of animal heat being influenced by the
nerves. By Sir Everard Home, Bart. V. P. R. S.
Read November 16, 1825.
1 HE conclusions drawn from my experiment upon the
deer's horns, published in the last volume of the Philoso-
phical Transactions, are so important, that I felt it a duty to
repeat the experiment in the ensuing season.
This I have done, and have the satisfaction to find that
the result agrees in every respect with that drawn from the
first experiment.
For the present experiment, I was furnished with a buck of
full head, seven years old, and in good condition ; the former
not having suffered from what was done in any respect
whatever.
As several disadvantages had arisen in the former experi-
ment from the horns having been bored ; they were now pre-
vented by applying a cincture of knitted worsted round that
part of the palm, the heat of which was to be ascertained,
three inches broad ; and the bulb of the thermometer was
received between this and the velvet of the horn. As soon as
the temperature was taken, the cincture was removed. All
liability to external injury was precluded, by confining the
animal in a stable.
A circumstance favourable to put the result of this experi-
ment to the severest test was, the heat of the atmosphere
being very different from that in the former season ; during
Sir EvERARD Home's additional pooofs , ^c, 61
the time of the experiment in 1824, it was 66^, in 1825, 84",
a difference of 18°.
This experiment was begun on the 12th of July, 1825, at
three o'clock. The temperature of the atmosphere was 84°,
that of both horns exactly 98 j . Immediately after Mr. Mayo
had divided the nerves, the heat of that horn was diminished
to 93 i°, and the heat of the other encreased to 99°.
The following register, showing the changes that took
place in the temperature of the horns and atmosphere, was
regularly filled up every day at three o'clock.
Day
Heat of
Heat of Horn
Heat of the
of July.
Atm.
operated on.
other Horn.
12th
84°
9Si''
99'
13th
84
93
98
14th
84
93
100
15th
85
96
99
I6th
S6
91
99i
17th
86
91
99
I8th
86
90|
98
19th
86
91
99
20th
85
91
99
21st
75
96
91
22d
76
93
93
2sd
74
93
93
After the two horns had become of the same temperature
the buck was allowed to join the herd. On the 28th of July
it was killed for the use of the table, which gave me an op-
portunity after death of examining the parts that had been
operated on. The horns had not shed their velvet, were
exactly of the same size, and equal in solidity.
^% Sir EvERARD Home's additional proof s of the
The parts where the nerves had been divided were care-
fully dissected and examined by Mr. Mayo, Mr. Caesar
Hawkins, and myself. The two cut ends of the nerves had
receded from one another, and the interval between them
was occupied by a dense newly-formed substance, which had
become a firm connecting medium, explaining satisfactorily
the restoration that had taken place in their functions. In
the former experiment this connecting medium was less
dense, and left a doubt upon my mind, which is now com-
pletely removed.
While engaged in this investigation I have had an oppor-
tunity, in the course of my professional duty as Surgeon to
Chelsea Hospital, to ascertain the effect of tying the trunk
of the artery that supplies the human thigh and leg on one
side, upon the temperature of the limb, compared with that
of the other, which remained in a natural state ; and con-
trasting this with the effect that has been stated to take place
when the nerve of one horn is divided.
As I intend to lay before the Society the detail of the
treatment of this case, of an aneurism in the external iliac
artery of the right side, which I trust will tend to the ad-
vancement of the science of Surgery on a future occasion,
I shall confine myself at present to the effect produced
upon the temperature of the limb, when the femoral artery
is obliterated immediately below Popart's ligament.
Before the artery was included in a ligature, the tempe-
rature of the foot, ascertained by a thermometer, was 93°;
that of the left, which was in a state of perfect health, 84°.
In ten minutes after the operation the heat of the foot fell to
87° ; in 30 minutes to 85, while the left foot remained at 84*.
source of animal heat being in the nerves, 63
In eight hours the heat of the left foot rose to 94**, probably
from the increased quantity of blood circulating through its
arterial branches, since next day the temperature fell to 88',
at which it continued stationary for four days ; the foot of
the aneurismal side in 24 hours fell to 84°, but on the
following day rose to 85°, and continued at or above that
temperature till the ligature came away.
Nothing can have been more satisfactorily proved than
that the heat of the parts of the body is diminished by dividing
the nerves going to them ; while, on the other hand, obstruct-
ing the arterial trunk of the thigh, even before it sends off the
great muscular branch, does not diminish the heat in the
smallest degree below the natural standard.
I have had many opportunities of ascertaining the tempe-
rature of the foot after the femoral artery has been tied in
the operation for the popliteal aneurism, and found it com-
monly one degree below that of the other foot, but the heat
of the two feet had never been ascertained before the opera-
tion, so that I was most probably deceived in the conclusion
I had drawn ; and in reality, the heat of the other foot had
been raised above the standard, instead of having been
depressed below it.
C64 3
V. The Croonian Lecture. On the structure of a muscular fibre
from which is derived its elongation and contraction. By
Sir EvERARD Home, Bart. V. P. R, S.
Read December 15, 1825.
J.N the course of the last 40 years I have given this Lecture
more frequently than any Member of the Society ; and, like
my predecessors, on those occasions, have taken up the sub-
jects most nearly connected with the inquiry for which the
Lecture was instituted.
As far back as the year 1818, while considering the mode
in which coagulated blood is rendered vascular, I brought
forward a magnified drawing of a muscular fibre made by Mr.
Bauer, showing it to be composed of a single row of globules
— ^ — parts of an inch in diameter, or in other words, of red
2,000 ^ ' '
globules deprived of their colouring matter.
From that time I had not proceeded further in investi-
gating muscular structure, but the appearance of the nervous
fibres of the great splanchnic ganglion in Mr. Bauer's mag-
nified drawings, which I laid before the Society last spring,
led me to consider that the organization of these fibres must
be so closely allied to that of muscles, that every physiologist
who examined the drawings, must immediately come to the
same conclusion ; and no sooner would those drawings be in
the hands of the public, than any one might with the greatest
Sir EvERARD Home on the structure of a muscular fibre, &c. 65
ease complete the discovery by an actual examination of
muscular fibres in the microscope.
Under this impression, I requested the President to appoint
me to give this Lecture, wrhich is to be read nearly at the
same time my paper on ganglions will be published ; so that
no one will have an earlier opportunity of applying what is
said of nerves in that communication to muscular fibres, the
consideration of which is the object of the present Lecture.
In Mr. Bauer's former examination of muscular structure,
that the integrant fibre might be more easily separated from
the fasciculus to which it belonged, we had gone into the
same error with those physiologists who have made diagrams
of the internal appearance of the brain, after coagulation,
and had boiled the muscle previous to the examination ; not
being aware that this process must decompose red globules,
should any exist, and cause the colouring matter to be sepa-
rated. Boiling would also destroy any connecting medium
by which the globules are united together ; so that, if I may
use the expression, there would only be the skeleton of a
muscular fibre remaining to be examined.
Upon the present occasion, therefore, the fibres belonging
to the fasciculi that compose the great muscle that lies upon
the back of the bullock's neck, to raise the head, were
selected, and were examined in 24 hours after the animal
was killed ; and we know that in all violent deaths, the
muscular fibres continue capable of contraction beyond that
period, after apparent death has taken place.
In this muscle the fasciculi are more loosely connected
together than in almost any other animal body ; and in the
interstices between them there is no fat ; but Mr. Bauer
MDCCCXXVI. K
66 Sir EvERARD Home on the structure of a muscular fibre
found that in this recent state the fibres are held so firmly
together by the mucus which surrounds them, and forms
them into fascicuh, that it was only under water he could
separate an integrant fibre for examination in the field of
the microscope.
In its mechanism, he found it to correspond with the
nervous fibre of a gangHon, differing only in the size of the
globules, which were larger than those of the fibre in the
ganglion in the proportion of —^ parts of an inch to — ^
and — ^— parts.
4,000 ^ ■■-
The elastic transparent jelly uniting the globules together,
had not the same elasticity as in the nervous fibre, so that
it could not be drawn out from the contracted state to double
its length without breaking.
The muscular fibre of a trout was treated in the same
way, and the result was the same ; the fibres were however
more brittle than those in the bullock's neck.
From these facts, in addition to those communicated in
the examination of the structure of ganglions, it is at last
ascertained, that the structure of the fibres of nerves in
general, and those peculiar to ganglions, as well as those that
compose muscles, is so far the same, that they consist of
single rows of globules united together by an elastic gelati-
nous transparent matter ; they differ however in the size of
the globules, and the degree of elasticity of the medium by
which they are united ; so that a less power will elongate a
nerve than the fibres of a muscle, and to a greater extent,
and it will restore itself with more velocity to a state of rest.
This structure of nerves and muscles, I consider to be
from which its elongation and contraction is derived, 67
demonstrated in the annexed drawing ; since I cannot
believe Mr. Bauer has been led into any error upon this
occasion ; as no error has been detected in his microscopical
observations for so many years continued, and the accuracy
of his representations, of what he has seen, no one can
doubt.
It is a curious confirmation of the acuteness of his eye, and
the accuracy of his glasses, that Leuwenhoek, who used a
single microscope, and says it is the best that can be made,
since the magnifying glass is the smallest speck that can be
seen, declares a muscular fibre to be made of globules less
than the red globules of the blood ; and Dr. Monro of
Edinburgh, who published his microscopical observations on
nerves and muscles, in the year 1783, made chiefly in the
solar microscope, goes so far as to consider muscular fibres
to be the continuation of nervous fibres, and gives an en-
graving of the mode in which the one terminates, or is lost
in the other. Dr. Monro, it is evident, had never seen a
single fibre either of a nerve or muscle, only fasciculi of them,
and found them so much alike as to be led to consider them
the same. Both Leuwenhoek and Monro, from the want
of a micrometer, were left to guess at relative dimension,
and in such guesses were often very unsuccessful.
The globules in the nervous fibre being smaller than in
the muscular, oversets Monro's theory of their being the
same ; but that both authors, with means so very inadequate
to those employed by Mr. Bauer, should have made such
approaches to the truth, is highly creditable to them, and
must prove highly satisfactory to Mr. Bauer, as well as to
the public.
68 Sir EvERARD Home on the structure, &c.
EXPLANATION OF PLATE IL
It represents muscular fibres magnified in different
degrees.
Fig. 1. A fasciculus of fibres taken from the bullock's neck,
sufficiently dissected to show the separate fibres ; magnified
loo diameters.
Fig. 2. A portion of the same fasciculus, the fibres more
unravelled ; magnified 200 diameters.
Fig. 3. A portion of a fibre in its contracted state, con-
sisting of five blood globules, and exactly one inch in length,
taken from the bullock's neck ; magnified 400 diameters.
Fig. 4. The same length of fibre extended to its utmost,
without giving way ; magnified 400 diameters.
The calf was selected for this last purpose, the elastic
medium between the globules being less brittle in the young
than the full grown animal.
J'Ml. Trnns. tADCOCSXTl.J'laZe XLp.SS.
^^rvjStoMi <^-
CegH
VI. An account of the heat of July, 1825 ; together with some
remarks upon sensible cold. By W. Heberden, M. D.
F. R, S.
Read January 12, 1826.
A.S I think it may not improbably be deemed an object of
some curiosity to the Royal Society to collect from different
parts, an account of the very unusual heat of last July, I
presume to offer the enclosed report of observations which
I made at that time, at Datchet, in Buckinghamshire, with
every precaution that suggested itself to me, to ascertain the
real temperature of the atmosphere, uninfluenced by adven-
titious circumstances. The observations were made with a
small sensible thermometer, which had been carefully
graduated.
On Friday July 15, the wind blowing from the south-west,
the thermometer was suspended in the shade of a large
laburnum on my lawn, at a height of about five feet and a
half from the ground. This tree was chosen, as admitting
the air in some degree to pass through it, at a time when the
wind and the sun were both in the same quarter. On the
subsequent days, the wind being in the east and north-east,
the thermometer was hung, at about the same height, from
an external branch of a very thick Portugal laurel, standing
likewise upon the lawn, at a distance from any building;
where it was exposed to the full influence of the wind, and
at the same time effectually sheltered either from the actual
70 Dr, Heberden's account of the heat of July y 1825 ;
rays of the sun, or from any object heated by it. I have
been the more particular in giving this account, because it is
often difficult, especially in great, or rapid changes of tem-
perature, to get observations made with sufficient attention
to avoid the neighbourhood of buildings, or other objects,
which may considerably affect the thermometer, and give an
appearance of heat sometimes greater, sometimes less than
the truth.
■ In order to ascertain the greatest heat, the thermometer
was repeatedly examined at short intervals during the hottest
period of the day. The highest degrees indicated, under the
circumstances I have detailed, were as follows :
July 15. - - 92° wind S. W.
17. - - 90°^
18. - - 96° [wind E.
19. - - 95°^
The 16th is not set down, because, though it was a hot
day, yet being several degrees cooler than the day preceding,
it was not thought worth while to examine the thermometer
with the same attention.
There is some reason to believe that an unusual degree of
heat was felt about the same time, not only in most parts of
Europe, but also in America.
The only instance of heat, that I am aware of having been
noticed in England equal to this, was in July 1808 ; on the
13th of which month the thermometer is stated, in the
Meteorological Journal of the Royal Society, to have risen to
93 J . On the 12th it had stood at 90°, and on the 14th it
was 91° ; the wind at the same time varying from east to
together with some remarks upon sensible cold, 71
south and south-west. On the hottest of these days Mr. Ca-
vendish's thermometer at Clapham rose to 96°.
It is true that other accounts have been recorded, some in
the Transactions of this Society, of hot days, or hot seasons,
which may have equalled, or possibly surpassed this: but
till within the last sixty years, the use of the thermometer
had hardly been understood sufficiently to enable one to rely
upon the vague statements of earlier times.
- To persons who may wish to compare this with the heat
of tropical countries, it will not be thought superfluous to
add, that the late Dr. Hunter, whose accuracy is well-known
to many members of the Royal Society, has stated in his
valuable account of diseases in the West Indies, that the
range of the thermometer at the hottest part of the day, and
in the hottest season of the year, at Kingston, in Jamaica, is
from 85** to 90®. In the coldest season it is about 5° lower.
It is not the least singular circumstance attending the heat
of last July, that it should have subsided without rain, without
lightning, without any change of wind, or any obvious
cause ; the succeeding days continuing dry and fair, as those
before.
I am tempted to add to the above some other observations,
which, if they are not immediately connected, are not entirely
unconnected with this subject; for it cannot have escaped
the attention of any person moderately conversant with
natural philosophy, that the index of a thermometer is a very
imperfect measure of what I may call the sensible cold, that
is, of the degree of cold perceptible to the human body in its
ordinary exposure to the atmosphere. For while the ther-
mometer truly marks the temperature of the medium in
72 Dr. Heberden's account of the heat of July, 1825 ;
which it is placed, the sensations of the body depend aUoge-
ther upon the rapidity with which its own heat is carried off.
And this is by no means confined to the actual temperature
of the air ; but whatever alteration of quality increases its
power of conducting heat ; and, above all, whatever currents
increase the succession of its particles in contact with the
body, the same will increase the sensation of cold. Hence
it is, that in very hot weather, the same stream of air which
would heat a chamber, will nevertheless be cool to the feel-
ing ; on the other hand, when the thermometer was more
than 80° below the freezing point, Captain Parry observed,
that while the air was still, the cold was borne without in-
convenience.
It therefore occurred to me, that the proper way to esti-
mate the sensible cold, would be, first to raise a thermometer
to a height something exceeding the natural heat of the
human body, and then to observe at what rate the quicksilver
contracted upon exposure to the air. For this purpose I used
a thermometer with a very small bulb, which might show
the alteration of heat in a short time. This I held to the fire
till it rose to about 120**, and then carried it in a warm glove
into the open air. I had with me an assistant with a watch
in his hand : and as soon as the mercury had descended to
100°, he began to count the seconds, while I continued to
observe the thermometer, marking the degree of heat at the
end of every ten seconds during half a minute. The result
rather exceeded my own expectations ; and (being, as far as
I know, the only experiments of the kind, ) I have thought
the Society might not dislike to be made acquainted with
them.
together with some remarks upon sensible cold. 73
The circumstances that particularly engaged my attention
were wind, and moisture. With these views the following
experiments were made, and verified by repeated trials.
Experiment i.
1 82 1 , January 3. A strong east wind.
The temperature of the air 31°.
The thermometer in this, and all the
experiments, being previously raised
to 100°, in the manner before-men-
tioned, the descent of the mercury
from that point was observed as fol-
lows :
After 10" it was 78®. Decrement 22**
20" 60° 18°
30" 52° 8°
By the decrements, it is to be under-
stood the descent in each successive
ten seconds. This is added, because I
consider it as the proper measure of
the sensible cold, so long as the ther-
mometer retains a heat approaching to
that of the human body.
Experiment 2.
1821, Jan. 4. No perceptible wind.
The temperature of the air 30°, the
atmosphere hazy.
After 10" therm. 89® Decrement 11*
20" 800 III 9*>
30" 71° 9°
Experiment 3.
1 8a I, Feb. 10. A strong east wind.
Temperature of air 47°. The atmo-
sphere clear, with sunshine.
After 10" therm. 82° Decrement 18°
20"
30"
73°
640
Experiment 4.
1 824, Jan. 9. A cold fog. No wind.
Temperature of the air 370.
After 10" therm. 92° Decrement 8*^
20" 85° 70
30" 790 6°
The most superficial view of these experiments shows the
prodigious effect of wind to increase the rate of cooling, which,
I apprehend, constitutes sensible cold ; so that in experiment 3,
though the thermometer suspended in the open air was 17°
higher than in experiment 2, yet the sensible cold was very
considerably greater ; but when there was no wind, even a
wet fog did not much, if at all, increase it. This, which at
first sight may appear contradictory to experience is not, I
believe, really so ; for though the power of such air to carry
off the heat of the body be indeed increased, yet so long as
we remain at rest, we are in great measure unaffected by it ;
MDcccxxvr. L
74 Dr. Heberden's account of the heat of July, 1825 ; &c,
so much the effect of wind exceeds that of mere moisture.
It is by walking, or riding, in such a state of the atmosphere,
that we produce on our bodies a current of moist air, which
is then felt in proportion to the rapidity with which we pass
through it. If it were thought worth while to bring this to
the test of the thermometer, the instrument should be made
to pass through the air at the same rate as the person would
move.
i:75D
VII. On the transit instrument of the Cambridge Observatory ;
being a Supplement to a former Paper. By Robert Wood-
house, Esq. Plumian Prof essor of Astronomy in the University
of Cambridge.
Read January 19, 1826.
Jln the brief account of the transit instrument which I had
the honour some time ago of presenting to the Royal
Society, I stated the circumstance of the instrument's devia- ,
tion from the meridian arising from the unequal expansion of
its braces ; but no instance was then given of the magnitude
of such deviation. I now subjoin one.
On the morning of Oct. 15, (civil reckoning) after ob-
serving the passage of Regulus, the southern shutters were
accidentally left open, so that when I returned to observe
the inferior culmination of the pole star, the sun was shining
on the upper western brace, the object-glass of the instrument
being towards the zenith. The effect of this was a retarda-
tion of more than 25 seconds in the star's passage, as will
thus appear :
-J
Oct. 14. {
o''59"20''
Polaris.
Rate of Clock
12 69 44
Polaris S. P.
— .17
Oct. 15. 1
0 59 20
12 59 17
Polaris.
Polaris S. P.
-^
Oct. 16.
0 59 19-5
Polaris.
Reversed the >
axis.
Oct. 17.
0 59 20
Polaris.
&c.
76 Mr. WooDHousE on the transit instrument, &c.
I now view, with great suspicion, all the observations of
the sun's transits, which I observed previously to the de-
tection of that source of inequality which is the subject of
the present, and of my former communication.
C77 3
VIII. Account of a series of observations y made in the summer of
the year 1825, for the purpose of determining the difference of
meridians of the Royal Observatories of Greenwich and Paris ;
drawn up by J. F. W. Herschel, Esq. M. A. Sec. R. S,
Communicated by the Board of Longitude.
Read January is, 1826.
Operations having been carried on to a considerable extent
in France, and other countries on the continent, for the
purpose of ascertaining differences of longitude by means of
signals, simultaneously observed at different points along a
chain of stations ; and the Royal Observatory at Paris, in
particular, having been connected in this manner with a
number of the most important stations, it was considered
desirable by the French government that the Royal Observa-
tory at Greenwich should be included in the general design.
The British Board of Longitude was accordingly invited to
lend its co-operation towards carrying into effect a plan for
that purpose ; and the invitation being readily accepted on
their part, I was deputed, in conjunction with Capt. Sabine,
in the course of the last summer, to direct the practical
details of the operation on the British side of the channel, and
to make the necessary observations. Every facility was
afforded us in making our dispositions, on the part of the
different branches of His Majesty's government to which it
was found necessary to apply. A detachment of artillery
was placed, by his Grace the Duke of Wellington, Master
78 Mr, Herschel's account of a series of observations
General of the Ordnance, under the orders of Capt. Sabine.
Horses, waggons, and men, were furnished for the convey-
ance of a tent, telescopes, rockets, and other apparatus ; and
four of the chronometers belonging to the Board of Admi-
ralty were placed at our disposal. The rockets required for
making the signals were furnished us from France. It would
have been easy, doubtless, to have procured them from the
Royal Arsenal at Woolwich ; but on the representation of
Colonel Bonne, to whom the principal direction of the ope-
rations in France was intrusted, it was thought more advis-
able to accept an offer made to us of any number which
might be required, prepared at Paris expressly for similar
operations, carrying a charge of 8 ounces of powder, the in-
stantaneous explosion of which, at their greatest altitude,
was to constitute the signals to be observed.
Our previous arrangements being made, on the 7th of
July I left London; and after visiting the station pitched
upon at Wrotham, which was the same with that selected
by Capt. Kater and Major Colby, as a principal point
in their triangulation in 1822; and finding it possessed
of every requisite qualification for the purpose of making the
signals, from its commanding situation, being unque;stionably
the highest ground between Greenwich and the coast, pro-
ceeded to Fairlight Down, near Hastings, where I caused
the very convenient observatory tent, belonging to the Board
of Longitude, to be pitched immediately over the centre of
the station of 1821, which was readily found from the
effectual methods adopted by the gentlemen who conducted
the trigonometrical operations in that year, for securing this
valuable point. Here, on the 8th, I was joined by Capt.
for determining the difference of meridians, &c. 79
Sabine, who, it had been arranged, should proceed to the
first observing station on the French side of the Channel,
there to observe, in conjunction with Colonel Bonne, the
signals made on the French coast, and those made at the
station of Mont Javoult ; which latter were to be observed
immediately from the observatory at Paris ; while, on the
other hand, it was agreed that M. le Lieutenant Largeteau,
of the French corps of geographical engineers, should attend
at Fairlight, on the part of the French commission, and
observe, conjointly with myself, the signals made at La
Canche, the post on the opposite coast (elevated about 600
feet above the sea, being nearly the level of Fairlight Down)
and also those to be fired from Wrotham Hill, which were
expected to be immediately visible from a scaffold, raised for
the purpose on the roof of the Royal Observatory of Green-
wich. By this arrangement, and by immediate subsequent
communication of the observations made at each station, it
was considered that the advantage of two independent lines
of connexion, a British and a French, would be secured
between the two extreme stations; i. e. the two national
observatories ; every possibility of future misunderstanding
obviated, and all inconvenience on either side, arising from
delay, or miscarriage in the transmission of observations, be
avoided.
With the assistance of Capt. Sabine, and by the help of
exact information as to the azimuths of Wrotham and other
nearer stations in the triangulation of 1821, with which Capt.
Kater had obligingly furnished us, and of which Fairlight
Church proved the most convenient, being close at hand and
favorably situated, and easily visible in the twilight ; and
8o Mr. Herschel's account of a series of observations
from the previously calculated azimuth of La Canche
(114° 30' E.); four night glasses by Dollond, provided at
the order of the Board of Longitude expressly for this opera-
tion, and which I had caused to be fixed on posts firmly
driven into the ground beneath the tent, were then pointed,
two on the station of La Canche, and two on that of Wrotham
Hill. Those directed to the former were of four inches clear
aperture, the others of three. In case of any difficulty arising
as to the pointing, I had taken care to provide myself with
an excellent eight-inch repeating theodolite, on the Reich-
ENBACH construction, by Schenck, of Berne ; but it was found
unnecessary to use it, as the night glasses were purposely
constructed with an azimuthal motion, and a rough gradua-
tion read off by an adjustable vernier, so as to allow their
being set at once a few minutes before the observations com-
menced, by taking Fairlight steeple as a zero point ; a cir-
cumstance which proved exceedingly convenient, as it allowed
of their being dismounted after each night's observations,
and removed to a place of security ; and thus rendering it
unnecessary to harass our small party by keeping guard in
our absence.
On the night of the 8th I had directed blue lights to be
fired at Wrotham, as a trial of the visibility of the stations,
or rather as a verification of the pointing of the telescopes ;
for on the former point there could be no doubt, the station
at Wrotham being situated precisely on the edge of the
escarpment of the chalk which borders the Weald of Kent,
and having been actually connected with Fairlight by direct
observation, while no obstacle but a low copse wood, over
which it might fairly be presumed that no rocket would
for determining the difference of meridians ^ &c. 8 1
fail to rise, separated it from a direct view of Greenwich,
at about 20 miles distance. Either from haze in the at-
mosphere, or from the too great distance, nothing was
seen that night or the next ; which however caused no unea-
siness, as we could depend on our instruments and informa-
tion. The next morning Capt. Sabine quitted Hastings, and
joined Col. Bonne, at his post, on the morning of the 10th,
the day appointed for the commencement of the observations ;
meanwhile I was joined by M. Largeteau, who remained
with me the v/hole time of their continuance, performing
every part of a most scrupulous and exact observer, as the
observations herewith communicated will abundantly testify.
The observations were continued during 12 nights, 10
signals being made at each rocket station every night. The
weather throughout the whole of this time was magnificent,
and such as is not very likely to occur again for some years ;
a circumstance of the last importance in operations of this
nature, where lights are to be seen across nearly 50 miles of
sea, and also by reason of the verification of the sidereal
times at the observatories by transits. One night only a local
fog deprived us of the sight of 1 3 out of the 20 signals ; but
on the whole, out of 120 made at Wrotham, no less than
112 were seen from Fairlight (about 40 miles) and 89 from
Greenwich ; while out of the same number made at La
Canche, qs were observed at the former post. I am sorry to
add, however, that owing to a combination of untoward cir-
cumstances, which no foresight or exertion on the part of
Capt. Sabine or myself could possibly have led us to calcu-
late on, or enabled us to prevent, and which the most zealous
endeavours on that of Col. Bonne failed to remedy, no
MDCCCXXVI. M
\
8d Mr. Herschel's account of a series of observations
less than eight out of the twelve nights' observations were
totally lost, as to any result they might have afforded, and
the remainder materially crippled ; so that a much more
moderate estimate of the value of our final result must be
formed, than would otherwise have been justified. Still it is
satisfactory to be able to add, (such is the excellence of the
method) that a result on which considerable reliance can be
placed, may be derived from the assemblage of the observa-
tions of these four nights ; and when it is stated that this"
result appears not very likely to be a tenth of a second in
error, and extremely unlikely to prove erroneous to twice
that amount, it will perhaps be allowed that, under such cir-
cumstances, more could hardly be expected.
for determining the difference of meridians, &c.
S8
I. Observations made at the Royal Observatory at Paris.
Station de I'Observatoire Royal. Feux de Mont-Javoult.
J
s«
Apparition
des Signans.
Noms
Avance
as
des
Observateurs.
Pendule
sur le tems
Sideral.
3
—>
Observes en tems
de la Pendule.
En tems Sideral.
Remarques.
A*
B
«
7
iS"* 15' 52".©
52.2
52.0
IS'' i5'4o''.3
40.5
40-3
Mathieu
Savary
Nicollet
brillant eleve.
8
26 17.5
26 5.8
Mathieu
-
excessiyement faible : observation douteuse ,
i8
9
35 52.9
53-1
52.5
35 41.2
41.4
40.8
Mathieu
Savary
Nicollet
ii".7
tres brillant, assez eleve.
10
45 56.0
55-9
45 44-3
44.2
Mathieu
Savary
-
faible, peu eleve.
55.6
53-9 1
Nicollet
t So in the original. (H.)
S
I
17 19 49.8
49.8
17 19 37.0
37-0
Mathieu
Savary
- -
brillant.
2
29 42.4
29 29.6
Mathieu
-
faible, eleve.
5
59 44.4
44.6
59 31-6
31.8
Mathieu
Savary
~ ~
assez brillant, peu ^leve.
»9
6
18 9 58.1
58,1
18 9 45.3
45-3
Mathieu
Savary
12.8
assez brillant, peu eleve.
8
29 54-3
54-4
29 41.5
41.6
Mathieu
Savary
~
peu brillant.
9
40 5.5
5.1
39 527
52-3
Mathieu
Savary
~ ~
brillant, tres eleve.
10
49 56-3
56.1
49 43-5
43.3
Mathieu
Savary
~ "
brillant, tres elev6.
s
2
17 33 507
»7 33 36.5
Mathieu
-
>
tres faible, observation tres douteuse.
3
43 45-5
45-5
43 31-3
3»-3
Mathieu
Savary
brillant, assez eleve.
4
53 49-8
53 35.6
Mathieu
-
tres faible, bas.
5
18 3 46.7
46.8
18 3 32.5
32.6
Mathieu
Savary
~
tres brillant, tres clev^.
20
6
13 48.6
48.1
'3 34-4
33-9
Mathieu
Savary
14.2
assez brillant.
7
23 49-9
49-7
23 35-7
35'5
Mathieu
Savary
~ "
peu brillant, assez ^leve.
8
33 53-3
53-6
33 39-1
39-4
Mathieu
Savary
-
peu brillant, assez eleve.
9
43 56.3
56.4
43 42.1
42.2
Mathieu
Savary
-
brillant, tres eleve.
10
53 54.2
54.6
53 40-0
40.4
Mathieu
Savary
brillant, tres eleve.
• La colonne (A) renferme les nombres qui ont ete trouves par les observations des feux. La colonne
(B) renferme les nombres de la colonne (A) corriges de I'avance de la pendule. Les nombres de la colonne
(B) sont ceux qui doivent etre compare au tems sideral absolu de Greenwich.
84
Mr. Herschel's account of a series of observations
Observations made at the Royal Observatory at Paris.
Station de I'Observatoire Royal. Feux de Mont-Javoult.
J
£g
Apparition (
les Signaiix.
Noms
Avance
des
Pendule
sur le terns
Remarques.
•^s
s
1— i 5Q
Observes en terns
de la Pendule.
En terns Sideral.
Observateurs.
Sideral.
A
B
%
I
17^27' 43."2
43-5
i7h27'26."8
27.1
Mathieu
Savary
-
peu brillant, peu elevd.
2
i7 39-5:
37 23-1:
Mathieu
-
brillant, tres eleve, j'ai viTune trainee lumineuse
de 37" a 40" j'estime le grand eclat vers 39".S.
3
47 48-3
48.7
47 31-9
32.3
Mathieu
Savary
-
assez brillant, tres eleve.
4
57 42-3
57 25.9
Mathieu
.
faible, peu eleve.
59.6
43-2
Savary
.
autre feu brillant et tres elevd.
5
18 7 375
18 7 21. 1
Savary
-
tres faible, bas.
21
7 57.3
57-4
7 40-9
41.0
Mathieu
Savary
i6".4
autre feu assez brillant et eleve.
6
17 41-3
17 24.9
Savary
-
faible et peu eleve.
17 46.8
»7 30-4
Mathieu
. -
autre feu assez brillant, eleve.
46.6
30.2
Savary
7
27 46.5
27 30-1
Mathieu
-
assez brilliant et eleve, explosion non instantanee.
46.4
30.0
Savary
8
37 51.6
37 35-2
Savary
« •
faible et bas.
37 57-2
37 40-8
Mathieu
.
tres brillant et tres eleve.
S7''^
40.7
Savary
lO
57 S^'7
57 40-3
Savary
.
premier feu, assez brillant, mais bas.
58 0.3
57 43.9
Mathieu
- -
autre feu, tres brillant, assez eleve.
?
I
17 31 29.9
29.6
17 31 12.3
12.0
Mathieu
Savary
- -
tres brillant, tres eleve.
2
41 29.3
29-3
41 11.7
11.7
Mathieu
Savary
*
assez brillant, peu eleve.
3
51 36.2
51 18.6
Mathieu
-
assez brillant et eleve.
36.4
18.8
Savary
•"i-j
4
18 I 33.3
18 I 15.7
Mathieu
-
assez brillant et eleve.
22
33-2
15.6
Savary
17.6
5
" 39-4
39-2
11 21.8
21.6
Mathieu
Savary
"
tres brillant et assez elev6.
6
22 1.3
I.I
21 43-7
43-5
Mathieu
Savary
*
assez brillant et eleve.
7
31 49-3
49-5
31 3»-7
319
Mathieu
Savary
"
assez brillant et assez eleve.
9
S» 47-5
47-3
51 29.9
29.7
Mathieu
Savary
assez brillant et assez eleve.
On a observe les signaux de feu donnes a Mont-Javoult pres de Gisors dans un petit cabinet situe dans
comparais, a I'aiae d'un chronometre, la pendule a celle qui
Ces comparaisons m'ont donne pour chaque jour I'avance de la pendule des feux sur celle de la lunette
meridienne et par suite sur le tems sideral. Je me suis attache a regler la pendule, qui est pres de la
lunette mferidienne par les passages durant le jour des sept ^toiles suivantes : Aldebaran, La Chevre, Rigel,
a Orion, Arcturus, « Couronne, a Serpent. J'ai observe 5^ de ces etoiles le 18, 3 le 19, 7 le 20, 4 le 21, et
5 le 22. J'ai calcule leurs positions apparentes d'apres les positions moyennts et les corrections in Right
Ascension donnees par Mr. South.
L. MATHIEU.
for determining the differe7ice of meridians, &c.
85
II. Captain Sabine's observations at Lignieres.
Chronometer of Motel, No. 39.
servations du 18 Juillet, huitieme jour.
Ob
Observations du 19 Juillet, le neuvieme jour.
Apparition des Signaux,
en terns de la montre.
Apparition des Signaux,
en terns de la montre.
Remarques.
Remarques.
i I'Orient.
i I'Occident.
f
i I'Orient.
i I'Occident.
I
b. niin. sec.
h. min. sec.
I
h. min. sec.
li. min. sec.
2
2
9 39 30-4
fa.
du.
3
4
5
6
9 49 33*4
9-59 34.0
10 09 37,2
10 19 33,6
9 54 52,
non vu.
10 14 54,du
non vu.
Signal de La Canche
[faible.
Signal de La Canche
[tres faible.
3
4
5
6
10 09 39,6
9 44
10 14
50
50^4
7
10 29 34,4
id.
7
-
10 34
49,6
8
non vu.
id.
8
9
10 49 328
id.
9
10 49 41,2
10 54
53,6
10
10 59 33.6
id.
10
10 59 30,0
II 05
01,4
Le Colonel Bonne a Mont-Javoult, moi seul.
Les signaux de Mont-Javoult bien vus, except^ le
7"'e qui etait faible.
•
Observations du 20 Juillet, le dixieme jour.
Apparition des Signaux,
en tems de la montre.
A
Remarques.
r
i I'Orient.
1
^ I'Occident.
I
2
3
4
5
6
7
8
9
10
h. min. sec.
9 49 39'6
10 09 27'6
10 29 27*2
10 49 30-5
li. min. sec.
10 54 47-6
faible.
Observations du 21 Juillet, le onzieme jour.
I
2
3
4
5
6
7
8
9
10
Apparition des Signaux,
en tems de la montre.
r- ' ,
i I'Orient.
b. |min. sec.
9 39 24-8
9 49 32-8
10 09 38-4
10 19 26*4
10 39 33-2
10 59 33-2
i I'Occident.
b. min. sec.
9 34 50-8
9 54 50-4
10 04 53*2
10 14 51.2
10 34 49-6
10 44 59-4
11 04 52,0
Remarques.
Le 6'ne signal de
Mont-Javoult
rasant rhorizon.
86
Mr. Herschel's account of a series of observations
Captain Sabine's observations of signals seen from Lignieres.
/-M I.:.
_ J.. T..
ti-i
yjubcivmiuiis uu zz juiiici.>
12""* jour.
Apparition des Signaux,
eu tems de la montre.
Remanjues.
•
a I'Orient.
4 roccident.
I
h. miu. sec.
9 29 1 8*6
h. min. sec.
9 34 55'6
2
-
9 44 50*8
3
9 49 22,0
9 54 53-6
4
9 59 i7>2
10 04 53,2
5
6
10 09 22,:
10 19 41 ',6
10 15 08,8
10 24 48,4
7
10 29 28,6
lo 34 58,8
8
!
10 44 57,6
9
Eclair.
10 54 48,0
lO
Eclair.
II 04 48,8
III. Colonel Bonne's observations of signals seen from Lignieres.
Chronometer Motel, No. 39.
Observations du 19 Juillet, le neuvieme jour.
Apparition des Signaux,
ea tems de la montre.
Remarques.
1
i I'Orient.
i I'Occident.
I
h. min. sec.
h. min. sec.
2
-
9 44 49*4
3
-
9 54 49'*
4
5.
I?: 09 39*4
10 14 50,4
6
7
^
10 34 49-8
8
9
10 49 41,0
10, 54 53,2
10
10 59 30,8
11 05 01,0
Observations du 20 Juillet, le dixieme jour.
Apparition des Signaux,
en tems de la montre.
Remarques.
1
4 rorient.
i I'Occident.
I
h. min. sec.
h. min. sec.
2
3
9 49 29>6
4
5
10 09 28,0
6
7
8
9
10 49 31,2
10
for determining the difference of meridians , ^c.
Colonel Bonne's observations of signals seen from Lignieres.
87
Observations du 21 Juillet, le 11"= jour.
I
2
3
4
5
6
7
8
9
10
Apparition des Signaux,
en terns de la montre.
i I'Orient.
h. min. sec.
9 39 24>6
9 49 32>6
10 09 38,8
10 59 33*4
i I'Occident.
Remarqnes.
h. min. sec.
9 34 50,8
JO 04 53,0
10 34 49,6
10 44 59,4
11 04 51,6
Observations du 2i Juillet, le 12"* jour.
Apparition des Signanx,
en terns de la moutre.
>s
Remarqnes.
1
A I'Orient.
1
i. I'Occident.
h. min. sec.
h. min. sec.
I
9 29 16,4
9 34 55'4
3
9 49 2i>8
9 54 53>4
4
5
9 59 I7'0
10 09 21,4
10 04 53,
10 15 08,4
6
10 19 41,8
10 24 48,2
7
10 29 28,2
10 34 58,6
8
-
10 44 57,4
9
10 49 23,
10 54 47,4
10
10 59 25,8 II 04 48,8
IV. Observations of the signals at the Fairlight Station, by Mr. Herschel.
By Baker's Chronometer, No. 744. Going M. T. beating half seconds.
First Day's Observations, July 11, 1825.
No.
I
10
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
9 41 7*6
9 51 3-5
9 56 23-2
10 r 4*8
10 5 59-2
10 II 3'o
10 21 4*4
«o 31 47
10 36 15-8
9 41 6-3
10 46 I2'4
10 51 3'3
II I 8*2
Remarks.
Seen, but the time not seized cor-
[rectly.
The train began at 9^4i'"2*. •
Train began at 9'' 20" 59*'5.
Seen by the gunners with naked eye
Very good.
Faint and indistinct. Seen by the
Precise. [gunners.
Train began at 59*.o.
Train began at 58'*5.
Very faint. Not seen by the men.
Seen by the men.
Second Day's Observations, July 12, 1825.
No.
I
10
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
9 26
9 36
9 36
9 4»
24-5
7-3
23-3
7'5
9 56
ID I
10 6
10 II
10 16
10 21
10 26
ID 31
10 36
10 41
10 46
10 51
10 56
11 I
17-8
8-8
317
9-2
23*6
lO-Q
22 5
8-0
21-9
8-1
i6-5
5 '4
16-4
6-6
■ Remarks.
Not the true explosion according
[to M. Largeteau
Very bright and sharp.
Lost by looking the wrong way.
Distinct.
Sharp and bright.
Extremely faint. Do\}l)tful.
Bright.
Distinct.
Bright.
Seen by Mr. Gilbert with naked
Bright. [eye.
Train began at i*.
? 1 5 '.5. The decimal correct.
Train began at o'.5.
Very bright. Train seen 4 or 5'.
Train began at o'.5.
88
No.
I
9
lo
Mr. Herschel's account of a series of observations
Mr. Herschel's observations of the signals seen from Fairlight.
Third Day, July 13, 1825.
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
9 31 6-o:
9 51 iz'5
9 56 27*6
10 6 28-5
10 II 16-5
lo 16 i8-i
10 21 14*1
Remarks.
A thick sea-fog suddenly came
on 2" before the time, though
perfectly clear till then.
A mere suspicion. Fog thicker,
Fog.
Fog.
Very faint, but distinct. Fog clear-
Distinct, [ing
Object-glasses examined. All co-
vered with moisture from the fog,
Well observed. Train seen.
Perfectly well seen.
Well seen ; but the glass dim, and
the fog coming on again.
Fog suddenly came on again, and
is surprisingly dense, so as
scarcely to allow the Mill to be
seen ; yet the stars are clear to
within 10 degrees of the ho-
rizon.
Fog.
Fog.
Fog.
Fog.
No.
I
Fourth Day, July 14, 1825.
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
26
31
36
4»
46
I
6
II
16
10 21
10 26
10 31
10 36
10 41
227
151
15-3
i6'4
28-1
15-2
17-4
15-4
ai-5
196
24-5
i8-8
25-0
15-2
17-5
i8-5
10 46 27-8
10 51 i6-6
La Canche 10 56 197
Wrotham 11 i 17-8
Remarks.
Very distinct ; train seen.
A pretty strong breeze.
Train perfectly well seen.
Train seen.
Train seen, Wind increasing.
? 23^.5 — am almost sure 2^"'^ is
the right.
Exploded irregularly at half its
height.
Train not seen. N. B. A star in
the field of the glass.
First a bright spark; then the
train ; then long after, a feeble
explosion at 27'. 8. The first
flash was brighter than the ex-
plosion.
Train feebly seen.
Fifth Day, July 15, 1825.
No.
I
2
10
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
V
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
h. m. s.
9 26 30-4
9 31 22-3
9 36 23-4
9 41 2y2
9 46 24*2
9 56 25*2
ID I i8-o::
10 6 23*5
10 II 23-4
10 16 i8-i
10 16 25-2
10 21 22'0
10 26 22"5
10 31 25-9
10 36 25-3
10 41 23-3
10 46 25*4
10 51 23-4
10 56 21-5
Remarks.
The first flash seen at 19'. 4 on
lighting the rocket. The flash
at 3o"-4 very bright.
Fainter than the i st flash of No. i .
A slight flash at lighting. The
rocket did not rise.
A flash at i6'-3 low down. The
flash at 24*'2 higher, and to the
right of the former. (The teles-
cope inverts. N. B.)
Faint, but very distinct.
r Signal regular and distinct, but
I observation uncertain from a
I violent noise in the adjoining
L field. ^
Sharp and good, but low.
Feeble and high, to the right of
the former.
{Certainly 'o, but the second un-
certain, from a violent noise
which drowned the beat of
the watch.
{Noise continued, and the ob-
servations uncertain on ac-
count of it.
Single explosion ; well observed.
Well observed.
Single explosion ; extremely f.
Well observed.
The train seen. No explosion.
The signal not repeated.
Sixth Day, July 16, 1825.
No.
I
4
5
6
7
8
9
10
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
h. m. s.
9 26 26'3
9 3' 3»-4
9 36 i9*»
24-3
9 41 30*0
9 46 38-0
9 51 26'I
10 I 31*6
10 21
10 26
lo 31
10 36
ID 41
io 46
ID 51
10 56
11 I
30-8
32*2
327
21-5
291
27*2
35-9
i8-2
299
296
297
Remarks.
Extremely faint.
The decimal correct, the second
possibly erroneous from noise.
Small bright spark.
Broad feeble flash, higher, and to
the apparent right
Exact on the beat.
Single bright flash.
Explosion distinct but unex
pected, as it happened before
the rocket reached its greatest
elevation.
Regular, and well observed.
Regular, and well observed.
Bright single flash.
Excessively faint.
Extremely faint.
Very bright.
Very bright. Observed with M.
Largeteau's glass ; a doubt
having arisen as to its correct
pointing, he having seen none of
the La Canche signals this even-
ing-
for determining the difference of meridians, &c.
Mr. Herschel's observations of the signals seen from Fairlight.
S9
Seventh Day, July 17, 1825.
La Canche
h. m. 8.
9 26 20-6
Wrotham
9 3» 36-3
La Canche
9 36 20'5
Wrotham
9 41 35'9
La Canche
9 46 27-0
Wrotham
9 51 37-2
La Canche
9 56 28*0
Wrotham
10 1 37-6
La Canche
10 6 28*2
Wrotham
10 II 35*7
La Canche
10 16 29-5
Wrotham
10 21 38-9
La Canche
10 26 27-8
Wrotham
10 31 41-0
La Canche
10 36 24-5
Wrotham
10 41 41-1
La Canche
10 46 38-5
Wrotham
10 51 317
La Canche
10 56 302
Wrotham
II I 38-7
Remarks.
Excessively faint but instantane
[ous.
: : A mere suspicion.
Well observed.
Telescope put in focus by a *.
Extr. faint, like a * of 10 m.
Exactly observed.
Very distinct ; perfectly well ob-
[served
: : A pretty strong suspicion.
The second doubtful, owing to
the lateness of the explosion.
: : : A faint suspicion.
Ninth Day, July 19, 1825.
No.
b. m. s.
Remarks.
I
La Canche
9 26 31-3
or 3 4' 3, certainly one or the other.
Wrotham
9 31 51-5
Very brilliant.
La Canche
9 36 33 0
Very bright ; well observed.
Wrotham
9 42 0-5
Remained extremely long in the
air, & mounted to a vast height.
La Canche
9 46 338
3
Wrotham
9 5^ 53*8
La Canche
9 56 29-1
4
Wrotham
10 1 56-4
La Canche
Missed by looking into the wrong
5
telescope by mistake.
Wrotham
10 II 51*1
Burst without rising.
La Canche
10 16 32-2
Train seen before the flash.
6
TTwo rockets fired. The first
Wrotham
10 22 2*5
< burst, the second observed as
( here set down.
La Canche
10 26 337
Train seen as well as flash.
7
Wrotham
10 32 248
La Canche
10 36 35'o
Extremely faint; the train as
g
bright as the flash.
Wrotham
10 41 597
Very bright.
La Canche
10 46 37-6
Train seen.
9
Wrotham
10 51 59-8
Mounted to an immense height.
La Canche
10 56 29*5
The first flash at lighting ob-
served; a second flash a long
while after, seen, but time not
taken.
Wrotham
11 I 51*0
First flash, rocket burst.
2 3-5
Second rocket, rose regularly.
No.
I
2
3
4
5
6
7
8
Eighth Day, July 18, 1825.
No.
b. m. tec.
La Canche
Wrotham
Remarks.
I
9 31 4>'9
Good.
La Canche
9 36 30'9
Good.
Wrotham
9 41 46*0
Good.
3
La Canche
9 46 297
Good.
Wrotham
9 5» 49-5
Good. ^
La Canche
9 56 328 Good.
4
Wrotham
10 I 50-3 Good.
La Canche
10 631-4 Good.
S
Wrotham
10 II 486
Good. Uncommonly bright.
6
La Canche
10 16 32*3
Good.
Wrotham
10 21 47-0
Good.
7
La Canche
10 26 23*4
Unexpected ; possibly i* wrong.
Wrotham
10 31 42*8
Good.
La Canche
Wrotham
8
10 41 47*2
La Canche
10 4& 27*0
: : 111 observed.
9
Wrotham
10 51 431
10
La Canche
ic 56 24*9
Perfectly well observed.
Wrotham
II I 420
Tenth Day, July 20, 1825.
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canehe
Wrotham
La Canche
Wrotham
La Canche
Wrotham
9 3' 43'3^^
9 36 36-2
9 41 58-0
9 4^ 37-9
9 51 56-0
10 I 567
10 6 44*1
10 1 1 57-9
Remarks.
Single flash.
Single p. bright flash.
Single flash ; train not seen.
10 22 4*4
10 31 58-1
10 41 58-0
10 51 58-0
II 1 58-5
!
A second fired, but both were
bad signals. Observation of
little value.
Large flash ; some seconds after
a small faint one.
MDCCCXXVI.
N
90
No.
I
2
3
4
5
6
Afr. Herschel's account of a series of observations
Mr. Herscuel' spb^ervations. of the signals seen at Fairlight.
Eleventh Day, July 21, 1825.
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
9 36
9 42
9 46
9 52
9 56
10 2
10 6
10 12
10 16
10 22
10 26
10 —
32
10 36
10 42
10 46
10 52
10 56
1 1 2
36-1
I 77
39-0
2-5
3-0
3-5
41-5
27
8-0
39-8
i-o
8-9
377
8-8
28-3
8-4
47*9
1*1
2*0
41-9
2-5
22'0
41-1
I'O
Remarks.
A most favourable night, and
transparent atmosphere.
Three rockets fired, but all burst,
and none could be observed.
Good. The rocket rose regularly.
Excellent.
/Three rockets fired in close
4 succession, all burst.
or I
' > Both burst without rising,
Twelfth Day, July 22, 1825.
7 Both well observed, but both
I burst without rising.
Excessively feeble, but certain.
[ Both burst without rising.
Two fired; the first missed;
both burst.
Very good; train seen; the rocket
remained very long in the air.
I Both burst.
> Both burst.
One only, which burst ; being the
19th out of 20 fired to night. ,
No.
I
2
3
4
5
6
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
26 35-5
32 9*o
36 39'^
42 7-0
46 42-5
52 8-6
56 42-5
2 101
6 58-0
12 07
10 26 48-2
10 32 3-0
8-9
10 26 48-2
47-c
58-8
:o 36{+7-°
10 42-! 7-2
10 46 36-9
( 2*0
'° 52 I 87
11 2 2*8
Remarks.
Very bright and fine.
Regular and good.
Train well seen.
Regular and well observed.
Train seen. Rose to a vast height
Regular and well observed.
Very good.
Perfect observation.
Very exact.
Burst without rising.
Two fired ; both burst.
Both burst.
Rose regularly, but rather a
doubtful observation.
All three burst.
Single. Train seen. '
Both burst.
:: Doubtful.
Burst.
V. Copie des Observations a Fairlight Down par C. L. Largeteau.
1825. (Baker's Chronometer, N**. 744.)
1 2 Juillet.
No.
h. m. sec.
Remarks.
I
La Canche
9 36 229
Wrotham
T.a CanrVip
9 41 7-9
3
Wrotham
La Canche
9 51 7'o
9 56 17-8
4
Wrotham
La Canche
10 I 8-6
10 6 317
5
Wrotham
10 II 9-4
6
La Canche
10 16 23-8
Wrotham
10 21 lO'O
La Canche
10 26 22-5
7
Wrotham
10 31 79
8
La Canche
ID 36 21-9
Wrotham
10 41 83
La Canche
10 46 165
9
Wrotham
La Canche
10 51 5'i
10 56 15-9
Wrotham
il I 117
il faut peut etre ii**
I"" 6.7s
1 3 Juillet.
No.
I
3
4
5
6
7
8
9
10
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
b. tn. 8.
9 56 27-3
10 6 28*5
10 II 14*6
10 16 17-9
10 21 14-0
Remarks.
for detennining the difference of meridians y ^c.
M. Largeteau's Observations at Fairlight continued.
91
No.
I
2
3
4
5
6
7
8
9
lo
14 Juillet.
La Canche
Wroth am
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
h. m.
8.
9 26
227
9 31
15-3
9 41
i6-6
9 46
280
9 5'
15-0
9 5^
17-4
10 1
19-4
10 6
21-8
10 II
19.5
10 16
23.6
10 21
18-9
10 26
25-0
10 31
15-3
10 41
i8-5
10 46
27-8
10 51
16-4
10 56
20-0
II I
17-9
Remarques.
15 Juillet.
I
2
3
4
5
6
7
8
9
10
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
9 3» 224
9 4» 23'o
9 46 24-8
ic II 23*4
10 21 22-5
lo 31 25-4
10 36 25.3
10 41 23-3
10 46 25*3
10 51 23*2
Remarques.
I
2
3
4
S
6
7
8
9
10
16 Juillet.
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
b. HI.
s.
1
9 31
3»-3
9 41
29-9
9 51
25-8
10 I
31*5
10 II
307
10 21
32*6
10 31
28-9
10 41
3S'3
10 51
10 56
11 I
30-0
297
29.8
Remarques.
17 Juillet.
I
2
3
4
5
6
7
8
9
10
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Cancbe
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
b.
m.
a.
9
26
20-8
9
31
36-0
9
36
20*3
9
41
35*9
9
51
37-0
9
56
277
10
I
37-4
10
6
27-9
10
II
3S-6
10
21
38-8
10
26
277
10
3>
407
10
36
248
10
4»
40-8
10
46 38-5 1
10
SI
32-0
II
1
38-4
Remarques.
Faible.
Faible.
Faible.
Faible.
92
Mr. Herschel's account of a series of observations
M. Largeteau's Observations at Fairlight continued.
1 8 Juillet.
I
2
3
4
5
6
7
8
9
lO
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
h-
m.
e.
1
9
36
3ro
9
41
46-4
9
46
29-8
9
5»
497
9
5t>
32-5
10
16
32-2
lO
21
46-8
lO
26
24-5
lO
31
42-5
lO
4'
47 '2
lO
46
30-3
lo
51
43 -o
lO
56
25-0
II
I
42-4
Remarques.
Faible.
Faible, Observation
douteuse
Observation douteuse
Observation douteuse
19 Juillet.
I
2
3
4
5
6
7
8
9
10
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
31
36
42
46
51
I
50-5
33.2
o'4
33-5
53-5
288
56-6
Remarques.
Observation douteuse
10 II 50*5
10 16 32*5
10 22 2-4
10 26 337
10 32 247
10 36 35-1
10 41
46
10
10 51
59-9
37'5
59-4
II 2 3-3
Observation douteuse
ou 14.7.
Extremement faible.
No.
1
2
3
4
5
6
7
8
9
10
20 Juillet.
9 31 43-5
9 41 58-2
9 51 56-4
10 1 56-5
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham 10 31 577
La Canche
Wrotham 10 41 58*3
La Canche
Wrotham
La Canche
Wrotham
10 II 57-5
10 22 4*5
10 51 57 9
Remarques,
incertajne.
incertaine.
No.
I
3
4
5
6
7
10
21 Juillet.
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
La Canche
Wrotham
9 36 36*0
9 42 7"6
9 46 389
6 39-8
12 o*4
26 38-2
32 1-9
8^
36 47'9
42 0-9
10 46 41-8
10 52 2-3
21-5
ri
Remarques.
Faible.
i'^'"^ Explosion.
2e
i^'^* Explosion.
I'""* Explosion.
2e
i*""^ Explosion
2*
for determining the difference of meridians, &e. 93
M. Largeteau's observations at Fairlight continued.
22 Juillet.
No.
b. m.
8.
Remarques.
La Canche
9 26
35-3
Wrotham
9 32
8-9
La Canche
9 36
39-8
Wrotham
9 42
6-9
La Canche
9 46
42-4
3
Wrotham
La Canche
9 52
«-5
4
Wrotham
10 2
97
La Canche
10 6
V7
5
Wrotham
10 12
07
Douteuse
La Canche
10 16
377
6
r
1-8
i«'* Explosion 1
Wrotham
10 22<
8-0
2^ lobs, incertaine.
3" J
La Canche
10 26
47 9
7
Wrotham
10 32 1
27
9-1
I- Explosion |p^^.^^^^^^^
8
La Canche
10 36
(;9-o
Douteuse,
Wrotham
La Canche
10 46
^7*4
9
Wrotham
La Canche
10 56
37-8
Tres douteuse.
Wrotham
II 2
27
VI. Observations made at the top of the Royal Observatory, Greenwich, on the
rockets at PFrotham.
July 11, 1825. The blue light and all the rockets were this evening distinctly seen
by the naked eye. The observations were made with telescopes, by three observers,
with the same chronometer. The chronometer was compared with the transit clock
both before and after observation. The blue light appeared about 9^ 21°* 25'.
Rockets.
I
2
3
4
5
6
7
8
9
10
App* Time I.
9^310.54.48
9 41 4925
9 SI 4575
10 I 47.5
10 21 46.75
10 31 46.8
10 51 45.8
11 I 50.4
- IL
54.3'
49.4
46.2
47.8
45.8
47-1
47.2
490
46.3
50.5
- III.
- - 54.28
- - 49-2
- - 45-8
- - 47-4
- - 45-4
Absent.
- - 47-3
- - 48.4
- - 46.2
- - 50.6
Mean*
54-30*
49.28
45.92
47.56
45.60
46.92
47.10
48.70
46 10
50.50
Chronometer
Clock.
Comparison before - -
gh ^^.m
16'' 12"" 22».o6
after - -
II 14
18 31 44.67
*» Mean Error and Rate of Sidereal Clock.
Mean of transits of 5 * ' I Corresponding mean error. Rate.
i6'» 24m I 48.36' — 0.02
Chronometer fast i" 17.97*.
The loss of the fifth observation in column I , was occasioned by some accidental derangement of the
telescope. The loss of the eighth was occasioned by the rocket passing through the field of view before
explosion. Observations 9 and jo, in column i, were made with the naked eye.
• In taking the mean of the three observations, those marked (: : ) doubtful, are not considered.
*• The transit observations employed throughout are reduced by the same system of corrections,
and mean right ascensions, as those used at the observatory of Paris for that purpose ; so that no error
in the results, from a difference of catalogues or corrections, is introduced.
94 . Mr. Herschel's account of a series of observations
July 12. All the signals, the blue light excepted, were this
evening visible to the naked eye ; the blue light could not
be seen at all :* the times of the explosions w^ere this even-
ing all observed with telescopes.
Rockets.
App* Time. I
II.
Mean.
: I
2
3
4
5
: 6
7
8
9
lO
9631 50'
41 50.75
51 50.0
10 1 51.5
II 51.8
21 53.0
31 51.0
41 51.2
51 48.0
11 I 49.8
9»'3i'"49.8»
41 50.6
51 50.0
10 I 51.S
II 52.2
21 52.8
31 51.0
41 51-3
51 48.0
11 I 49.7
o
o
a
bo
G
49.90"
50.67
50.00
51.50
52.00
52.90
51.00
51.25
48.C0
4975
Chronometer.
Comparison before
After
9" 11°
II 12
Clock.
16* 32" 19.94'
»8 33 39'8o
Mean Error and Rate of Transit Clock.
Mean of 5 • ' I Corresponding error. I Rate.
16" 24"" I 48.27* I —0.08
From mean comparison on nth, to ditto on 12th, chronometer gained 1.02'.
Chronometer fast i" 18.99'.
Rockets I and 6 exploded twice, at an interval of about three seconds. The
first explosion, in each case, was the one observed ; the second, not being expected,
was lost.
• None was fired. (H.)
for determining the difference of meridians , &c. 95
July 13th. All the signals were visible to the naked eye.
Rockets.
App' Time I.
II.
III.
Mean.
I
2
3
4
S
6
7
8
9
10
9" 31-55.8'
9 51 55-75
10 I 55.0
II 57.4
21 57.2
31 56.6
41 56.0
51 55.8
9^31- 55.6 »
51 56.0
10 I 55.2
" 57-3
21 57.0
31 56.6
41 56.0
51 55.6
11 I 56.2
55.6'
55.2
S4.8
57.6
57.0
56.5
5S.8
55.3
56.2
55.67.
55-87
55.0
57-43
57-07
56-57
55-93
55-57
56.2
Comparison. Before -
After -
Chronometer.
9'' 16"
II 13
16'' 41" 16.63'
18 38 35-75
Mean Error and Rate of Sidereal Clock.
Mean of 6 * »
16'' 40"
Mean error corresponding.
48-39'
Mean rate.
+ 0.14
Comparison 12th to ditto 13th. Chronometer, + 0.87.
Chronometer fast 1° 19.86*.
The 2d rocket was lost by all the observers : it did not appear till some seconds
after the time specified; and when it did appear it exploded immediately. It
exploded about 9'' 42" 22*.
The loth rocket in column I. was lost by a derangement of the telescope.
The third observation, column III. is doubtful to half a second.
96 Mr. Herschel's account of a series of observations
July 14.
Rockets.
I
2
3
4
5
6
7
8
9
ID
App* Time I.
9" 31'
42
51
10 I
12
22
31
42
52
2
II
>59.o»
0.7
59.0
58.8
3-4
3-2
59-4
2.4
0.3
1.8
II.
59.2"
0.4
59.0
59-4
3-3
31
59.2
2-3
0.5
2.0
III.
Mean.
59.10-
0.55
59.00
59.40
3-35
3-15
59-30
2.35
0.5
1.9
Comparison of Chronometer and Clock.
Chronometer
Before
After
II"
15
Clock.
i6'»40"' 11.87'
18 44 32.13
Mean Error, and Rate of Sidereal Clock.
Mean of 7 * ' Mean error corresponding.
i6»'2i'» 48.25'
Mean rate.
— 0.16
Comparison 13th to ditto 14th + 0.38.
Chronometer fast i" 20.24".
July 15th. The third, fourth, and last rockets disappeared
without any explosion. In the third column something like
an explosion was noted at the beginning of the ascent of the
third rocket, but no dependance can be placed on it.
Rockets.
App* Time. I.
II.
- III.
Mean.
I
2
3
4
1
7
8
9
10
9>»32'" 8.68
42 8.8
- - 8.5.
- - 8.4s
8.5'
8.93
9.20
8.03
II. 2
9-23
9.07
- - 9.0
- - 9-0
::lo 2 3.0
- - 9.2
- - 8.0
10 12 9.4
22 8.1
32 10.9
42 9-3
52 9.2
- - 9.0
- - 8.0
- - II. 2
- - 9.2 -
- - 9.0
- - 11.5
- - 9.2
- - 9.0
Comparison of Chronometer and Clock.
Chronometer.
Before
After
91*24"
II 10
Clock.
i6'>5^'° 9.80'
18 43 27.04
Mean of 6 • "
iGh o
Mean Error, and Rate of Sidereal Clock.
Mean error corresponding.
47.92-
Mean rate.
— 0.30
Comparison 14th to ditto 15th + 0.47
Chronometer fast i" 20.71s.
for determining the difference of meridia?is, &c, 97
July 16. The third rocket disappeared without explosion.
ckets.
App*Time. I.
I
9'»32°'i7.os
2
3
4
42 15.6
10 2 16.8
5
12 16.4
6
22 18.0
7
32 14.9
8
42 21.0
9
52 15.8
10
II 2 15.2
II.
III.
Mean.
16.9s
15.6
17.2
16.3
17.9
14.8
21.0
15.2
15.1
16.98
i6.93«
15.4
15-53
17.1
17.03
I6.S
16.40
18.3
18.07
I5.I
14-93
21.0
21.0
15.4
»5.47
155
15.27
Comparison of Chronometer and Clock.
--
Chronometer.
Before 9^18"'
After II 12
Clock.
i6'» 55" 5.29s
18 49 24.06
Mean Error and Rate of Sidereal Clo
Mean of 5 * » Mean error corresponding.
16.6 47.60*
ck.
Mean rate.
- o.33«
Comparison from 15th to i6th — 0.31.
Chronometer fast i" 20,408.
MDCCCXXVI.
o
98 Mr, Herschel's account of a series of observations
July 17th. The loss of observation 1, in columns I. and
III. was occasioned by the observers mistaking the mi-
nute. It was however very accurately taken by the second
observer.
Rockets.
App* Time I.
II.
- III.
Mean.
I
9'' 32" 20.18
20. i»
2
9*42'"20.0»
42 19.9
:: _fc _•» ip.18
19.95
3
52 20.8
- - 21.3
- - 21.3
21.13
4
10 2 21.4
- - 21.4
- - 21.4
21.40
5
12 19.8
- - >9-3
- - 19-2
1943
6
22 22.9
- - 22.8
- - 22.9
22.87
7
32 24.8
- - 24.8
- - 24.8
24.8
8
42 25.0
- - 25.0
- - 25.0
25.0
9
-
-
:: 10 52 16.0
—
10
II 2 22.5
- - 22.6
- - 22.6
22.57
Comparison of Chronometer and Clock.
Chronometer.
Before 9'* 21°'
After II 11
Clock.
17'
3.68*
18 52 21.72
Mean Error and Rate of Sidereal Clock.
Mean of 7 ♦ s j Mean error.
15" 30°
47-56'
Mean rate.
— 0.06
Comparison from 16th to 17th — 1.40.
Chronometer fast i*" 19.008
The ninth rocket exploded the moment it began to ascend; the time noted
cannot be depended on.
for determining the djffereyice of meridians, &c. 99
July 18th. The first, seventh, ninth, and tenth rockets
could not be observed ; one or tv^^o exploded without ascend-
ing ; the remainder did not explode at all.
Rockets.
App' Time I.
II.
- III.
Mean.
I
—
2
p** 42" 29. IS
- - 29.0'
- - 29.1'
29-07'
3
- 52 32-1
- - 32.3
- - 32.2
32.20
4
lO 2 33.3
- - 33-0
- - 33-2
33-»7
5
- 12 31.1
- - 31.0
- - 31.6
31-23
6
- 22 29.8
- - 29.6
- - 29.7
29.70
7
—
8
- 42 29.9
- - 30.0
- - 29.9
29.93
9
—
10
—
Comparison of Chronometer and Clock.
Chronometer.
Before 9* 37"
After II II
Clock.
i7>»22°' 3.55'
18 56 18 95
Mean Error and Rate of Sidereal Clock.
Mean of 6 ♦*
i6''o°
Mean error.
47- 30*
Mean rate.
— 0.26*
Comparison from the 17th to i8th — 0.93.
Chronometer fast i" 18.07'.
100 Mr. Herschel's account of a series of observations
July 19th. The fifth rocket could not be observed.
Rockets.
App* Time I.
II.
- III.
Mean.
I
2
3
4
5
6
7
8
9
10
9i»32»43.i'
- 42 41.0
- 52 34-1
10 2 36.9
- 22 42.9
- 33 4.8
- 42 40.1
- 52 40.0
::ii 2 43.3
- - 43 -o"
- - 40.9
- - 43-0"
- - 41.0
43^03"
40.97
34-13
36.9
42.9
4^75
40.1
39^97
43^7
- - 34-1
- - 36.9
- - 4^-9
- - 40.0
- - 40.0
:: -43.1
- - 34-2
- - 36-9
- - 42.9
- - 4-7
- - 40.2
- - 39-9
- -43-7
Comparison of Chronometer and Clock.
Chronometer.
Before 8" 48-"
After II 10
Clock.
16*" 36"" 53.84'
18 59 17.02
Mean Error and Rate of Sidereal Clock.
Mean of 3*' I Mean error. | Mean rate.
1 6*' 50""
47.i6«
— 0.19*
Comparison from i8th to 19th — 1.81
Chronometer fast x™ 16.268
Observation 10 in columns i and 2 doubtful to half a second.
for determining the difference of meridians , &c. lois.
July 20. The rockets this evening were miserably bad;
five only were observed ; the eighth however might have
been a good one ; it was lost by all the observers looking:
for it too late.
Rockets.
App' Time I.
- - - n.
- - - III.
Mean.
I
2
3
4
5
6
7
8
9
<
^h j2>n 36.6s
52 56.2
10 22 45-7
36.73
- - 56.0
- - 45-8
10 32 53.0
36.93
- -56.1
10 12 39.2
- 22 46.1
- - 53->
36.73'
56.1
39-2
45-87
53-05
lO
Comparisons of Chronometer and Clock.
Chronometer. Clock.
Before 9'' 6" le** 58" 53.06s
After II 10 1 19 3 »3-34
Mean Error and Rate of Sidereal Clock.
Mean of 5 • ^ I Mean error. I Mean rate
iji* 40"
47.228
-^0.03"
Comparison from 19th to 20th, + 0.35
Chronometer fast i"* 16.618
102 Mr. Herschel's account of a series of observations
July 21. The rockets much worse this evening than they
were last. Only one out of the whole number mounted at
all. All the others were seen, but nothing was sufficiently
definite to admit of being noted. *
Rockets
1
2
3
4
S
6
7
8
9
lO
App* Time I
9'' 42'" 48.88
II.
48.8'
- III.
- - 48.8'
Mean.
48.8»
Comparisons of Chronometer and Clock.
Clock.
!»» 9n> 50.88*
Chronometer.
Before 9'' 13""
After II 10
19 7 9.93
Mean Error and Rate of Sidereal Clock.
I •». Error. Rate.
i;"* 26"".
47-37
+ 0.20'
Comparisons from 20 to 21, +1.02
Chronometer fast i™ 17.63'
* It is much to be regretted that some attempt at least to note them was not
made. Had it been done, this night's result, which is now dependent on a single
signal, might perhaps (as they were for the most part tolerably well observed at
Wrotham), have been placed nearly on the same footing with the rest. H.)
X
for determining the difference of meridians y ^c. 103
July 22. Rockets extremely bad ; four only could be
observed.
Rockets.
App»Time I.
- - - II.
- - - III.
Mean.
I
2
3
4
1
7
9»'32'" 51. 2S
- 42 49-9
- 52 51-4
51-35'
- - 49.8
- - 5'-3
10 2 52.4
5i.4«
49.6
51-3
- - 52-4
51.32.
49-77
5«-33
52.4
8
9
10
—
Comparisons of Chronometer and Clock.
Chronometer. Clock.
Before 9* 23" I 17^ 23™ 48*
After
II II
19 12 5.59
Mean Error and Rate of Sidereal Clock.
Mean of 5*'.
15^ 47^
Mean error.
47-57'
Mean rate.
+ 0.21
Comparisons from 21 to 22, + 0.32.
Chronometer fast 1™ 17.95*
The means of the Comparisons, with the true Sidereal
Time corresponding.
July II
12
»3
H
15
16
17
18
19
20
21
22
Chron.
lo'^4m 30'
10 II 30
ID 14 30
10 15 O
ID 17
10 15
10 16
10 24
9 59
10 8
10 II
10 17
o
o
o
o
o
o
30
o
Clock.
171122™ 3.36*
17 32 59.87
17 39 56.19
17 42 22.00
17 50 18.42
17 52 14.67
17 57 12.70
18 9 11.25
17 48
18 I
5-43
3.20
18 8 30.405
18 17 56.79
True Sidereal
Time.
7'»2i™ i5.o»
7 32 11.60
39
41
49
5»
56
8
47
o
7
17
7.80
33-75
30.52
27.09
25.14
23-97
18.27
15.98
42.03
9.20
104 Mr. Herschel's account of a series of observations
True Sidereal Time of the explosions.
r
July II.
Rockets.
I
2
3
4
5
6
7
8
9
lo
True Time.
i6''48^
-58
17
18
8
18
28
38
48
58
8
18
13.3928
30.54
28.82
32.11
31-79
34.85
36.56
39.80
38.84
44.8
July 12.
Rockets.
I
2
3
4
5
6
7
8
9
10
True Time.
16^52™ 24.98s
17 2 27.38
28.27
31.51
33.66
36.21
35.93
37.82
36.19
39-59
18
12
22
32
42
52
2
12
22
July 13.
Rockets.
I
2
3
4
5
6
7
8
9
10
True Time.
i6'> 56" 26.45=
17
18
16
26
36
46
56
6
16
26
29.95
30.73
34.81
36.09
37.33
38.23
39.50
41.77
July 14.
July 15
July 16.
Rockets.
True Time.
Rockets.
True Time.
Rockets.
True Time.
I
lyh Qin 26. 1 OS
I
17'' 4'n 31.64*
I
lyh gm 37.06*
2
— 10 29.20
2
— 14 33.72
2
— 18 37.34
3
20 29.30
3
3
4
— 30 31.34
4
4
— 38 42.03
5
— 40 36.94
5
— 44 39.04
5
— 48 43.04
6
- 50 38.39
6
— 54 39-39
6
— 58 46-36
7
18 0 36.00
7
18 4 44.21
7
18 8 44.95
8
— 10 40.87
8
— 14 43.88
8
— 18 52.58
9
— 20 40.66
9
— 24 45.35
9
— 28 48.68
10
— 30 43.71
10
10
— 38 50.12
July 17.
July 18.
July 19.
Rockets.
True Time.
Rockets.
True Time.
Rockets.
True Time.
I
i7'»i2ro 38.098
I
I
17** 20"* 56.91*
2
— 22 39.58
2
I7h jgm 46.25'
2
— 30 56.55
3
— 32 44.40
3
— 36 51.02
3
— 40 51.34
4
— 42 44.30
4
— 46 53.62
4
— 50 55.77
5
— 52 43-96
5
— 56 53.31
5
6
18 2 49.06
6
18 6 53.42
6
18 II 5.09
7
— 12 52.63
7
7
— - 21 28.65
8
— 22 52.48
8
18 26 57.05
8
- 31 5.58
9
10
— 42 55.29
9
10
9
- 41 7.1 1
— 51 12.50
10
July 20.
Rockets.
True Time.
July 21.
Rockets.
True Time.
July 22.
Rockets.
True Time.
1
2
3
4
5
6
7
8
9
10
1 7'' 24"! 46.90*
17 45 9.60
18 4 55.95
— 15 4.28
— 25 13.12
I
2
3
4
5
6
7
8
9
10
I7*»38m 56.10*
I
2
3
4
S
6
7
8
9
10
1
I
7^32°' 53.27*
- 42 53.36
- 52 56.56
8 2 59.28
for determining the difference of meridians, ^c. 105
Statement of the method of combining and calculating the Obser-
vations, and obtaining the Rates of the chronometers.
Previous to stating the result of these observations, it will
not be irrelevant to explain the method pursued in reducing
them, and the principles on which the calculation has been
made ; and it may be here remarked, that the brevity and
facility of the computations which will appear to be required
for this purpose, is not the least recommendation of the
method itself.
Suppose A and Z to be the two extreme points whose
difference of longitudes is to be determined, and at each of
which the true sidereal time is supposed to be known by
transits of well determined stars and registered by exact
clocks, or carefully compared chronometers. Intermediate
between these, suppose two, or any number of stations,
B, C, &c. chosen, at each of which are placed observers fur-
nished with telescopes and good chronometers ; and again,
intermediate between these, and in the order
A, a, B, 6, C, c, Z,
let posts or stations a, b, c, be selected, at which signals are
made, by the explosion of gunpowder, the discharge of
rockets, the extinction of lamps, or otherwise, at regular
concerted times, and so arranged that the signals at a shall
be visible from both A and B ; those at b from both B and C ;
and those at c from B and Z. Now let a signal be made at
a, and observed both from A and B, and the moment of its
happening noted at A by the sidereal clock, and at B by the
MDCCCXXVI. P
106 Mr, Herschel's account of a series of observations
chronometer ; then, if the observations were perfect, the
difference of the clock at A, and the chronometer at B, would
become exactly known. Let this be denoted by A — B.
A short time after, let a signal be made at 6, and observed by
the chronometers at B and C, whose difference (which we
will in like manner denote by B — C,) becomes thus precisely
known at the time of making the signal. In the same manner
may the difference C — Z of the chronometer at C and the
sidereal clock at Z be known at the moment of explosion of
a signal at c ; and so on, if there be more intermediate
stations.
Now, the clocks at A and Z being all along supposed to
keep strict sidereal time, if the watches at B, C, did the same,
it is manifest that the difference between any two of them
determined at one moment would be the same at every
other ; and therefore the intervals elapsed between the
signals would be out of the question, and the observations
might all be regarded as simultaneous ; so that the sum of
the differences (A — B) + (B — C)+ (C — -Z) =A — Z
would express strictly the difference of the true sidereal times
at the extreme points, /. e, their difference of longitudes ex-
pressed in time, without any further calculation or reduction.
It is equally evident that, whatever be the rates of the
watches, if the intervals elapsed between the signals were
infinitely small, so as to reduce their gain or loss in these
times to nothing, the same would hold good. Since this
however cannot be the case, it is obvious that the difference
of longitudes so obtained will be affected by the rates of the
watches and the intervals of the signals, which must accord-
for determining the difference of meridians ^ &c. 107
ingly be allowed for. Now, as the intervals at which the
signals are made at the successive stations are small (only
five minutes), the gain or loss of the watches used may be
calculated for such small times to great nicety ; and, if the
watches were regulated to sidereal time, and of any ordinary
degree of goodness, the correction on this account would be
almost insensible ; or, if regulated, as is generally the case,
to mean time, the reduction from mean to sidereal time only
need be applied, neglecting the deviation of the rates from
strict mean time. The calculation then becomes of extreme
simplicity ; for since the watches have equal rates, we have
no occasion to apply aiiy correction to their observed dif-
ferences ; and it will suffice to apply to the uncorrected
value of A (= A — Z, or)
^^ (A —B) + (B' — C) + (C - Z")
the mere reduction from mean to sidereal time for the in-
terval elapsed between the first and last signal ; or in other
words (regarding the whole operation as a species of tele-
graphing), for the time the message has occupied in its trans-
mission from one observatory to the other.*
For example. On the 19th, a signal was made at Mont
Javoult, and noted at Paris to have happened at 18^ 39"" 5^' -5
true sidereal time at Paris, and at Lignieres at 10^ 49°* 4i'.o
by the Lignieres Chronometer. About 5°* after this, a signal
made at La Canche was observed at Lignieres to happen at
.10" 54° 53'-s, and at Fairlight at 10^ 46" sT-S by the Fair-
light chronometer. Finally, a third signal was made about
5" later still at Wrotham, and observed at 10^ 51°" 59^.4 by
• Might not telegraphs be employed to ascertain the difference of longitudes of
the stations between which they are established ?
108 Mr. Herschel's account of a series of observations
the Fairlight chronometer, and at 18^ 41"" 7M1 true sidereal
time at Greenwich. The calculation then stands thus
+ A = +i8 39 52 '50. — B = — 10 4941-00
+ B'=+io 54 53-20 — €'=— 10 4637-50
+ C"=+io 51 59-40 — Z"=:— 18 41 7-11
B' — B rz + o 5 i2'2o
C"— C'= + o 5 21-90
Sum o 10 34-10
Sum = +38" i44°i65s-io —^S^ i36"858.6i
r: o'' 8° 79*-49 or rso" 9" 198.49 the uncorrected value of A
Reduction from mean to ^
Sid. T. for an interval y= + 1*73
of io"» 34»-io . . J — — — —
o 9 21-22 r= A
the corrected difference of longitudes.
Such is the result of the transmission of a single signal
along the line, and such the whole calculation required to
deduce it. It is chosen at random from among the observa-
tions, yet is probably entitled to at least as much confidence
as any value hitherto previously obtained ; a circumstance
which sets the excellence of this method in a very strong
light.
Such would be the process of calculation in the simplest
state of the data, viz. when the signals are seen along the
whole line without a failure, so that each message so trans-
mitted arrives at its destination and gives a complete result.
But this (in the present instance at least) has not been always,
or'generally the case. It has much more commonly happened
that a signal made at one station (a for instance, has not been
simultaneously observed, or not observed at all, at A and at B,
while the other signals, at 6, c, &c. have been regularly seen
and registered. In every such case (of which endless combi-
nations may occur) a link of the chain fails, and no result can
be obtained from this series of observations taken singly. A
very slight consideration will suffice to show that were we
for determining the difference of meridians , &c, 109
to reject all such broken series, the observations of a whole
night might easily be thrown away, though capable of
affording a result quite as good as any other. Such a case
actually occurs in the observations of the 18th, where no
complete transmission of any one signal from end to end of
the line took place, yet the mean result of that night's obser-
vations deviates less than two-tenths of a second from the
result finally adopted as the truth.
The most advantageous way of employing such a broken
series of observations as we have described is not at once
obvious. It may depend on circumstances too nice for cal-
culation, and which can be felt only by the observers them-
selves. The fairest however, and that which by employing
all the observations according to one uniform rule leaves
nothing to partiality, seems to me to be the following.
Let A be the time marked by the sidereal clock at the first
extreme station A, then calling E the time marked by the
same clock at any assumed arbitrary epoch, A — E will denote
the sidereal time elapsed since that epoch. Call j3 the rate
or sidereal time of the chronometer at the 2d station (B),
/3 being supposed negative when the chronometer loses, (as
for instance when it shows mean time). At the same moment
that the clock at A marks A, let this chronometer mark B,
then, since /3(A — E) is the quantity it has gained, since the
epochs, B — jG (A — E) must be the time it would have indi-
cated, if instead of gaining or losing, it had kept true sidereal
time since the epoch. Consequently (the clock being sup-
posed to have no rate) A— | B— /3 (A— E) jor A— B+ iQ(A-E)
will be the difference of the clock and chronometer reduced
jio Mr. Herschel's account of a series of observations
to this epoch, i. e. the difFerence they would have indicated if
instead of comparing them at the time A, they had been
compared at the time E.
Every signal simultaneously observed at A and B, gives a
direct comparison of the clock and chronometer ; but it is
only when thus reduced to a fixed epoch that these compa-
risons become comparable inter se ; but when so reduced
their mean may be taken, and is of course preferable to the
fesult of any single comparison. Hence if we put
P = mean of all the ( A — B) + /3 x mean of all the (A - E)
P will express the difference of the clock and chronometer
at the epoch more probably than any of the individual values
derived from single observations.
It follows therefore that at any other sidereal time A', the
time indicated by the chronometer at B, (or B') may be cal-
culated from the expression
B'= (A'^P) + /3 (A'— E) (a)
more probably than it can be derived from any single actual
observation. This equation gives
A'= ^^^^j^=^ = B' -f P — ^ (P + B' — E)
neglecting squares and higher powers of jS, whence the
time by the clock at A becomes known at any instant in
terms of that shown by the watch at B.
Now let a signal be made between B and C, and noted to
happen at the moment marked B' by the watch at B, and C
by that at C. Let )3 and y denote their respective rates on
sidereal time ; then since B' — jS (A'— E) and C— y (A'— -E)
are the times they would have marked had they kept strict
for determining the difference of meridians , &c. iii
sidereal time since the epoch, their difference reduced to the
fixed epoch will be
(B'— C')-(;3-y)(A'_E)
in which, substituting for A its value above found, we get
(B'_C')-(/3-y)(P + B'-E)
neglecting powers and products of jS and y. Putting then
Q=:mean of all the{B*-- C)-(3'-r/)—meanofall the (P+B'— E)
we get the most probable value of the difference of the
chronometers at the epoch which can be obtained from any
number of such comparisons.
Finally, if we make a comparison at any time A" (Paris
Sid. T. ) between the watch at C and the clock at z, and call
their indications at that moment C" and Z", their apparent
difference will beC — Z", and their difference reduced to the
epoch will be
(C— Z") — y(A'— E).
But Q being the most probable difference between the chro-
nometers B and C at the epoch, and (jS — y) the difference
of their rates
Q + i^-Y){A"-E)
will be their difference at any other moment A"; hence
B''-~ C'= Q + (/3 - y) (A"-- E).
But by the equation (a:) since B" and A" are correspond-
ing times, we have
B"=A"-P-|-^(A''— E).
Consequently substituting this for B" we get
C'= A"-,P — Q + y ( A"-E)
whence A"= P + Q + C"— y { A"— E)
= P + Q + C"-y (P + Q + C"-E)
neglecting the square and higher powers of y :
112 Mr, Herschel's account of a series of observations
Consequently, still neglecting the same things we get
C— Z"— y {P+Q+C— E}
for the difference of the timekeepers C and Z reduced to the
epoch, and putting
R= mean of all the (C - Z") - y.mean of all the (P+Q+C— E)
R will be their most probable difference reduced to the fixed
epoch.
P, Q, and R, being thus obtained, we must obviously have
for the correct difference of longitudes,
A = P + Q+R.
Now, substituting for P, Q, R, their values, this gives
A=mean of (A — B) + mean of ( B' — C) + mean of(C' — Z")
-{-^.mean of {A — E)
+ {y^P).mean of {P + B'— E)
— y.mean 0/ (P + Q + C" — E)
that is, reducing,
A =zmean of (A— B) + mean o/(B'— C) + mean o/(C"— Z")
+ (3. mean of A-\' {y — fi), mean ofB' — y, mean of C
_P/3_Qy.
This value of A is however susceptible of still further
reduction by substituting for P and Q their values ; which if
done, and the powers and products of (3 and y neglected, as
has all along been done, we get
A = mean of {A — B) + mean o/(B'— C) + mean of (C'^Z")
+ ^.mean of A + (y — jS ) mean of B'— y. mean of C"
— /3 . mean of (A — B) — y. mean of (B' — C)
that is, finally (since the numbers of the observations of
A and of B are necessarily equal, and therefore the mean of
the values of A — B is equal to the mean of A — the mean
for determining the difference of meridians, &c. lis
of B, and so for the rest) reducing and striking out all the
terms which desti*oy each other.
A = mean of A — mean ofB-{- mean ofB' — mean of C •{•
+ mean of C" — mean of Z"
+ (2 { mean of B—mean of BI-^- yimean ofC — mean of C\
or simply, denoting by A, B, A', B', &c. no longer the indi-
vidual observed times (to which there will be no occasion
again to refer) but the means of all those which have cor-
responding observations.
A = A — B+B'— C+ C — Z"
+ i3(B-B')+y(C~C"(
This expression is, as it obviously ought to be, independent
of the arbitrary epoch E, which may be assumed any number
of hours or days before or after the observations.
The first line of this value of A may be regarded as an
approximate one ; the second as a correction depending on
the rates of the watches ; and it is clear that the several
portions of which this correction consists are the respective
gains of the chronometers on Sid. T. during the mean
amounts of the delay of the message between the several
stations, taking the expression in its algebraical sense, where
a negative delay corresponds to an anticipation.
If all the signals succeeded, the coefficients of jS and y
would be each o** 5", and the amount of the correction would
be ( jQ + 7 ) •-|-T= ^^ • It would therefore require no less
a deviation of one of the chronometers from its assumed
rate than 29^" per diem, or of both of them i4j, and the same
way, to produce an uncertainty in the result to the amount
of a tenth of a second; deviations incompatible with the
MDCCCXXVI. Q
114 Mr. Herschel's account of a series of observations
character of ordinary good watches, not to speak of chro-
nometers.
The worst case that can happen is where the first signal
only at a gives corresponding observations at the stations
adjacent, the last only at 6, the first again only at c, and so on.
In this case the coefficients of /3 and 7 would each equal the
whole interval between the first and last signal at each post,
or (in the present case) 1^ so"". The correction here would be
^2 X 24 — 16
In this extreme case, the sum of the deviations of both
watches from their assumed rates, need only amount to i'.6
to produce an uncertainty of a tenth of a second in the result ;
and though such a case as here supposed is in the last degree
improbable, yet as a certain approach to it is not unlikely, it
may be of use to show how the rates of the watches, if not
otherwise known, may be obtained, or if known, verified, by
the observations themselves.
If we consider the observations on two successive nights,
at two of the extreme stations, A and B for instance, calling
A and B the means of the simultaneous observations on the
first night, and A^ B^ on the second, we have, assuming for
an epoch some time E = any number of days before either of
the night's observations,
b^r- P = A— .B + iG(A — E)
But since this is generally true, if the observations be made
in sufficient number on both nights to destroy their indivi-
dual errors in the mean result, we must also have
P = A,-B,+ /3(A,-E)
equating which we get
for determining the difference of meridians, &c. 115
A — B — /3(A — E)=A,— B, — ^(A, — E)
whence we find , , „ , , ^ „,
^ (A, — B,) — (A — B)
H — A, — A
In this formula it is to be observed that A, and B^ are each
greater than 24 hours ; but as timekeepers only register
excesses above 12 hours and its multiples, if we wish' to
denote by A^ and B^ the mere readings off of the time-
keepers, we must put 24*^ + A^ and 24^ + B, for A^ and B^ if
the interval be one day ; 48^ + A, and 48^ + B, if two days,
and so on, so that (n being the number of days elapsed)
^^ ^^* — 5 = (A.-B,)-(A-B)
f^ n X 24*+ A^ — A
In like manner may the rate