464
THE HONGKONG GOVERNMENT GAZETTE, 29TH MAY, 1886.
GOVERNMENT NOTIFICATION.-No. 199.
The following Magnetic Observations made during the Year 1885 are published for g information.
By Command,
Colonial Secretary's Office, Hongkong, 29th May, 1886.
FREDERICK STEWART
Acting Colonial Sec
MAGNETIC OBSERVATIONS MADE DURING THE YEAR 1885. The observations of Declination and Horizontal Force were all made with the Kew p Unifilar Magnetometer Elliott Brothers No. 55. The dip observations were made with the dip- Dover No. 71, partly with two new steel needles, No. 5 and No. 6, the axes of which I caused made of chilled bell metal in 1884. There is no doubt, that by selecting proper pieces of this the maker could produce axes turned as accurately as those made of steel, and I can recommenc needles for use on expeditions and in damp climates. Observations were made also with needle 1 and No. 2, after they had been repaired and furnished with new axes by Dover.
The circle-reading on the Unifilar Magnetometer corresponding to true north was determin observations of Polaris reflected from the speculum. Observations of the Sun near the first ve looking alternately towards and away from the Sun, were found to agree with the observati Polaris but were discontinued as being less accurate than the latter.
The observations of Horizontal Force are expressed in C. G. S. Units (one centimete. gramme, one second) but the monthly synopsis exhibits X, the Horizontal, as well as Y, the Ve and the Total Forces (which latter have been computed by aid of the observed Dips): also in E Units, (one foot, one grain, one second) and in Gauss's Units (one millimeter, one milligramm second). The value of log K at 20° Cent. adopted was 3.44973 in January and 3.44904 in D ber. The values for the intermediate months have been interpolated. The Induction-coeffici 4.917. The reduction of m, the magnetic moment of the vibrating magnet at a temperature of t to the freezing point of water is: +0.000 260t + 0.000 002 44t.
The distances between the centres of the deflecting and the deflected magnets are expressed m m' P
centimeters and the value of the constant P employed in the formula of reduction: X
is: +8.3424.
The times of vibration exhibited in the table are each derived from 12 observations of the time occupied by the magnet in making 100 vibrations, corrections having been applied for rate of chrone- meter and arc of vibration.
The mean value of the magnetic moment of the vibrating magnet was 0.51644 in English Units and 674.25 in C. G. S. Units.
OBSERVATIONS OF MAGNETIC DECLINATION AND DIP,
Declina-
1883.
H. K. M. T. tion,
East.
Ob-
server.
H. K. M. T.
ہے
B,
Dip, North.
Needle.
January,
February,
17 3h 0m p0°45′ 36′′ W.D.
15 2 17 2 40
p
0 46 13
P
0 45 29
59
March,
April,....
17 2 25
p
0 45 34
18 2 55
p
0 41 45
13 3 46
P 17 3 30 15 3 0 p 15 3 0 p 12 4 0 p 18 4 10
24d 3h 50m p 32°28′,36 24 4 15 p
32 28.39 13 3 46 p
32 21.25 32 26.75
90o 0.00 32°28′.36 No. 5
39
28.39 21.25
26.75
Р
May,
18 2 50 p 0 43 45 F.G.F.
16 3 15
Р
16 4 0
June,
16 2 50 p 0 43 55
17 3 17
""
P 17 4 5 P
July,
15 2 55 p0 45 56
August,
............-་་
222222
p
32 23.12 41 44.40 42 6.40 41 50.30 41 55.75 32 23.15 90 0.00 32 28.67 32 27.85 p❘ 32 29.93 32 26.50 32 30.35 16 3 47 Р 32 25.15 16 4 35 p 32 27,61 17 4 5 32 22.52 17 4 45
p 32 28.08 31 3 50 32 28.02 P 31 4 35 p 32 28.41
23.12
22
24.79
22.71
23.15
"3
28.67 27.85
""
29 .93 26.50
29
30.35
"
25.15
"
27.61
1J
22.52
28.08
>
28.02
"
28.41
COLO CO CO ŁO KO LO KO LA CO LO CO 1∞ ∞ IN
5
5
}
6
2
"
September, October,.....
1 3 27
P
0 44 44
39
...
17 3 8
P
0 45 49
November,..
17 3 0
p
December,................
15 2 40 17 2 20
0 47 46
p 0 45 23 p 0 45 8
"
17 4 5
P 17 4 47 p 16 3 25 p 16 4 15 p
32 26.92
32 27.42
32 27.37
32 26.34
W.D.
"
14 2 36 p 32 23.67 14 3 14 p 32 22.44 16 3 29 P
32 22.08
16 3 29 p 32 22.72
: རྣ མ མ མ ཐཱ བྷསྶ ནྟ
26.92
27.42
27.37
26.34
23.67
22.44
22.08
22.72
:-212-256