THE HONGKONG GOVERNMENT GAZETTE, 15TH MAY, 1886.
422
We have then :
б a sin (4-8) sec 8-b cos (4-8) sec + ▲ T-a-T
c sec. 8. Where T is the observed clock-time of the mean of the transits over the wires, reduced t middle wire, ▲ T the clock-correction, a the right ascension and 8 the declination of the star the latitude of the observatory. Upper or lower sign is to be taken according as the clamp is
& must be substituted for 8. or east of the meridian, and when the star is sub polo 180°
The sun is observed through a circular opening (larger than the object glass) in a white,
screen.
—
THE F
mean daily table, where
Period.
1885. 1-10,.......... ₤10–20,.......... The total number of transits observed in 1884 amounted to 505, including 55 transits of P20-30,........
The inclination of the 30- 9.......... 25 of the Sun and 19 of the Moon and also a number of southern stars. was observed 150 times.-The total number observed in 1885 was 313, including 14 transits of P9-19,.........
The inclination of the ax 20 of the Sun and 7 of the Moon and also a number of southern stars. observed 117 times.
The values of the constants in 1884 and 1885 are exhibited in the following table. values are given under the same date, the last one was obtained from Polaris sub polo. Where is drawn, it indicates that the instrument was adjusted.
19- 1,..
1-11,. 11-21,.
Whe
21-81,. 31-10,
10-20,. 20-30,. 30-10,.
Date.
C.
b.
a.
Date.
C.
b.
a.
Date.
b.
10-20,
20-30,........
30- 9,........
1884.
1884.
Oct.
5,--1".65
"
6,
- 1.80
+0.37
21,
-1.50
- 1.60
+2".27 +12".6 Nov. 29,
+13.7
Dec. +14.9
-3".70
+4".3
1885. Jan. 2,
-1".05
+ 3".50
30,
-3.15
+ 7.5
53
1,
-2.85
6.9
Jan.
+0.40
14-24,.......
**
31
22,
-1.10
+15.6 "3
-5.50
5,
-1.20
+0.45
23,
-0.75
-2.35
+16.4
9,
-5.15
20,
-2.20
""
"
25,
-1.50
-2.22
+13.3
9,
-6.72
39
10,
-1.35
-7.03
29
Oct. 31,
Nov. 4,
-2.12 + 4.6 -1.05 + 6.2
10,
-5.57
++++
وو
22,
-2.78
clock sto
*
+ 6.8
Mar.
5,
-3.45
the thunde
.8
15, -0.45
-7.70
25
et springs.
a the rate
Dec. 11,
:
+0.42
0.0
Nov.
5,
+2.95
+ 5.4
""
11,
+1.60
-
1.5
Apr. 13, -0.90 June 7,
+3.42
-1.05
+2.62
were con
5,
-1.65
:
+ 3.6
12,
"
+0.70 + 2.7
وو
.8,
-2.25
13,
...
+1.52 +3.20
3.9
39
13,
-0.83
June 25, + 1.3
-2.10
3.47
.8
15,
+1.77
1.9
26, -2.25
3.42
"
35
99
39
22,
-0.60
- 4.78
5.2
19,
-0.50
0.2
27,
-2.25
4.07
و,
33
23,
-1.20
-3.67
3.7
21,
+0.20
2.2
Oct. 2,
-2.10
2.95
39
99
24, -1.50
-4.63
+ 4.3
22,
+0.87
2.1
29,
-2.40
5.00
**
-4.45 25, -2.25
+ 4.5
26,
-0.26
+1.3. Dec.
8,
-2.25
9.93
>>
52
-2.45 27, -1.35
+ 6.8 "
28,
+1.03
3.8
ཉ
29, -1.05-13.92
"
28, -1.05
-3.40 5.1
29,
+1.67
+ 2.3
mean ra
e tempera ormal equ
A disc of white enamel with black cross mounted on a metal plate with movement by screws is fixed on a slate slab, which is cemented into a solid masonry pier built about 70 feet nos the transit instrument. It is observed through an object glass of about 66 feet focal length, wh fixed in a brass plate just inside the northern shutter.-There is also a meridian mark 11354 sequenc the south, which may be observed across the harbour except of course at night or in foggy weather baromet eh in the 1 has the form of an obelisk and is marked with a vertical black line between two black circles.
The shutters of the transit room are a foot wide, quite sufficient for an object glass of 3 the mear aperture. The room has 6 windows and 2 doors to equalize temperature but was unfortunately buat this co the bot arrival here.
28 my the wrong
side of the observatory, the windy side, before The standard sidereal clock by E. DENT & Co., was described by the makers as being of the the ra best possible construction and the study of its rate affords therefore a testimony of the quality ofd, as th work at present issued by that firm.-It has a cast iron back, which is firmly screwed to iron brate ex cemented in the pier placed in the clockroom. The pendulum has the zinc and steel compensatin next originally designed for the Transit of Venus Expeditions. The dial is painted black with white ha mean-t
It has also a giunished. and figures. The dead-beat escapement is executed with the greatest care. contact apparatus omitting one second each minute, with horizontal and vertical adjustments of one and works a three-current relay by aid of one or two bichromate cells. A sympathetic electro-m second pi dial in the transit room is worked by a strong current through the relay.
every ho This dial is an exact counterpart of the dial of the standard clock.-It was actually wo clanché ce 1884 and part of 1885 but the contact apparatus was found to interfere with the going of the star the clo clock. The teeth of the wheel on the second hand arbor, that press the springs while the per beneath a is not touching the pallets, being so very badly constructed that they are of unequal size even teracting unaided vision. The sympathetic dial had therefore to be rejected and the observations are nople comi with a chronometer which is subsequently compared with the standard clock. While the observanic co are, as at present, confined to the determination of local time, the use of a chronometer is correct convenient as the sympathetic dial, the keeping in working order of which takes up. par clocks assistant's time. Besides, the omission of a second every hour on the dial is a serious drawback om surf and ear-observations, of however great advantage it is in working a chronograph. -*
2 feet
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