669784-1885-Report-on-the-Height-of-Victoria-Peak- — Page 1

222 SUPPLEMENT TO THE HONGKONG GOV" GAZETTE OF 7TM MAR., 1885.

GOVERNMENT NOTIFICATION.---No. 107.

The following Report on the height of Victoria Peak, furnished by the Government Astronomer, is published for general information.

By Command,

Colonial Secretary's Office, Hongkong, 7th March, 1885.

ON THE HEIGHT OF VICTORIA PEAK.

W. H. MARSH,

Colonial Secretary,

The height of Victoria Peak has been calculated (from the monthly means of observations made

2h'

H

during 1884) by aid of Ferrel's tables derived from the formula:- b'

H=60521.5 (log. Bʻ-log B) (1+.001017 [t′+t-64°]) (1+.189) (1+.189) (1 + —2——) (1 + 7 )

(1+.002606 cos. 2×).

T

-) −

I

H represents the difference of height betweca the upper and lower stations-here, the Peak and the Observatory; B the barometric pressure reduced to 32° Fahrenheit at the upper station as exhibited in the third column of the following table; B' the same at the lower station as exhibited in the second column; t the temperature of the air at the upper station, t' the same at the lower station as exhibited in the fifth and the fourth columns; b the tension of aqueous vapour at the upper station, b' the same at the lower station as exhibited in the seventh and the sixth columns; h' the height of the lower station above mean sea level-bere, 107.1 feet, and a the geographical latitude of the upper station-- here, about 22° 16′.

Month.

B'

B

t

b'

H

1884.

ins.

ins.

ins.

ins.

feet.

January,

30.093

28.302

62.3

55.4

0.443

0.404

1713.4

February,

30.061

28.244

57.0

50.8

0.377

0.337

1723.0

May,

29.752

28.038

74.8

68.4

0.736

0.662

1703.9

June,

29.662

27.965

80.1

72.4

0.850

0.767

1709.0

July,

29.581

27.893

82.2

74.7

0.908

0.816

1712,6

August,

29.625

27.937

81.8

74.6

0.886

0.802

1709.0

September,

29.685

27.993

81.2

73.9

0.811

0.741

1706.0

October,

29.920

28.198

77.2

70.0

0.698

0.634

1707.8

November,

29.396

28.228

67.8

60.9

0.490

0.457

1715.6

December,

30.119

28.323

59.6

53.3

0.318

0.281

1706.1

Mean,

29.849

28.112

72.4

65.4

0.652

0.590

1710.6

It will be remarked that no correction for barometric gradient has been applied, in fact the height of the barometer reduced to sea level does not differ more than a fraction of a thousandth of an inch between the two stations, nor is a correction for diminution of gravity with increasing height called for as both barometers are mercurial.

The mean of the resulting differences of height increased by 107.1 fect, the height of the lower station above mean sea level, gives finally the height of the Peak at the highest level of the rock where the look-out tower is erected. The differences in the results exhibited in the last column of the table are due principally to the fact, that it has been assumed that the mean of the temperatures of the air at the Observatory and at the Peak, represents accurately the average temperature of the air between the two stations. The probable error of the final result has been determined from these differences, to be about 14 inches. The height is therefore determined with such accuracy and a more accurate result can only be obtained from several years observations.

Altitude of Victoria Peak-1818 feet+1} feet above mean sea level.

Hongkong Observatory, 5th February, 1885.

W. DOBERCK, Government Astronomer.

Printed and Published by NORONHA & Co., Printers to the Hongkong Government, Nos. 5, 7, and 9, Zetland Street.