674926-1884-Government-Notification-No-456 — Page 1

SUPPLEMENT

HONGKONG GOVERNMENT GAZETTE of 27th December, 1884.

GOVERNMENT NOTIFICATION.--No. 456.

lowing Report from the Government Astronomer, is published for general information.

By Command,

al Secretary's Offic, Hongkong, 27th December, 1884.

HONGKONG OBSERVATORY.

Magnetic Observations made during the year 1884.

W. H. MARSII,

Colonial Secretary.

rvations of Declination and Horizontal Force were all made with the Kew pattern Unifilar tor. Elliott Brothers No. 55. The Dip observations were made with one of the needles 1 of the Dip-circle, Dover No. 55, the other needle being found useless on my arrival here, it apparently been insufficiently packed. The needle No. 1 quickly deteriorated and became use- rly as August, although I did my best to preserve it. The Swedish man-of-war Vanadis the port in October an officer was good enough to lend me two needles by Dover, and the first n on October 22nd was made with No. 2, the second observation as well as that made on the day were made with No. 1. The mean of these observations was adopted for September,

r. November and December.

The circle-reading on the Unifilar Magnetometer corresponding to true North was determined by rvations of Polaris reflected from the speculum, and also occasionally by observations of the Sun bril stars near the first vertical. The typhoon in September blew the roof off the magnetic hut, the mean of the observations made in August and October was adopted for September.

The abservations of Horizontal Force are expressed in C. G. S. Units (One centimeter, one gramme 4) but the monthly synopsis exhibits X, the Horizontal, as well as Y, the Vertical, and tl. T! Forces, which have been computed by aid of the observed Dips, also in English Units, (one foo

in ene second) and in Gauss's Units (one millimeter, one milligramme, one second). Me value of log K adopted is 3.44997 at 20° Cent., the Induction-Coefficient is: 4.915 the dm, the magnetic moment of the vibrating magnet at a temperature of t° Cent. to the freezing water is: +0.000 293t + 0.000.0016t2.

The distances between the centres of the deflecting and the deflected magnets are expressed in

ters and the value of the constant P employed in the formula of reduction:

m

m'

P

(1

X

X

T2

The times of vibration exhibited in the table are each derived from 12 observations of the time by the magnet in making 100 vibrations, corrections having been applied for rate of chrono-

are of vibration.

The mean value of the magnetic moment of the vibrating magnet was 0.54245 in English Units, 17.20 in C. G. S. Units.

OBSERVATIONS OF MAGNETIC DECLINATION AND DIP.

H.K.M.T.

Declination, East.

Observer.

H.K.M.T.

A.

B.

Dip North. Observer.

18 11 30 a.

16. 4. 6 p. 0° 51′ 15′′| 17 10 55 {L.

52 2 47 50

W.D.

>>

15 12 58 a. 0 49 25

>

15

16

10 6 16

** co co m

3 12

2 17

3 15

222

P. 0 47 47

""

0 46 13

15

194 3h. 27. p. 19 5 20 P.

14 1 25 P. 32 16 12 20 p. 14 5 10 16 1 16 P.

32° 23'.2

82

:

p. 0 48 18

15 4 {}

31

17 12 32

15 12

43

p. 0 47 52

"

3 0

p. 0 47 48

15

21 5 53

3

50

21

18 1 26 p. 0 48-39

27

17 11 51 •3. 0 46 59

29

22 5 47

23

5 20 p.

ÂÂ ÂÂÂÂ Â Â Â Â Â Â

19.9

32 21.2

P.

41 51.3 41 52.6

3885

88=

90° 0.0 32° 23′2 F.G.F. 23.7 90 0.0

23.7 W.D.

90 0.0

90 0.0

19.9 21.2 21.8

""

""

57 52.0 34 42.2 42 7.3 41 50.9

25.0

"J

28.2

90 0.0 90 0.0 20 3 45 p. 42 8.9 41 37.9

32 27.2 90 0.0 32 28.5 32 33.9

27.2

وو.

28.5

>>

33.9

"}

22.9

22 5 10 p. 32 31.4 90 0.0

31.4

32 29.6 90 0.0

29.6

32 29.4 90

0.0

29.4

F.G.F.

W

13 1 22 p.0 45 46

31

14

4 35 p.0 45 12

བ ཁ

"J

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