# Appendix F.
# REPORT OF THE DIRECTOR OF THE ROYAL OBSERVATORY, HONGKONG, FOR THE YEAR 1925.
## 1.-GROUNDS AND BUILDINGS.
The grounds were kept in order by the Botanical and Forestry Department with the assistance of the Observatory coolies.
Underground Chamber for Seismograph and Clocks.-The diurnal inequality of temperature in the underground chamber is negligible and the change in 24 hours seldom exceeds 0°.3 F. The annual range amounted to 11°.3 (F) in 1924 and 11°.9 (F) in 1925. Changes of humidity are at times considerable; as, for example, from November 12d 17h to 13d 16h when the relative humidity decreased from 77% to 43% in response to a fall in the open air from 90% at 12d 15h to 38% at 13d 4h.
In the following table the mean monthly temperature and humidity in the Underground Chamber are compared with the temperature and humidity in the open air. As the air in the Underground Chamber is always still, humidity tables for calm air have been computed and used for obtaining the relative humidity from the readings of the dry and wet bulb thermometers.
### Mean Monthly Temperature and Relative Humidity in the Underground Chamber and in the Open Air, during the year 1925.
Month 1925 In Underground Chamber In Open Air Excess of Underground Chamber over Open Air Temperature Relative Humidity Temperature Relative Humidity Temperature Relative Humidity January 71.6 56.8 February 69.3 56.0 March 68.9 63.7 April 69.1 65.2 83 May 72.9 95 June 76.4 96 July 79.0 98 82.3 +14 August 80.0 82.5 79 September 80.2 81.4 74 +3.7 October 79.1 66 75.4 64 3.7 +2 November 77.6 65 71.9 5.7 December 74.5 +7 62.9 58 +11.6 Range 11.3 26.5 27Appendix F.
REPORT OF THE DIRECTOR OF THE ROYAL OBSERVATORY, HONGKONG,
FOR THE YEAR 1925.
1.-GROUNDS AND BUILDINGS.
The grounds were kept in order by the Botanical and Forestry Department with the assistance of the Observatory coolies.
Underground Chamber for Seismograph and Clocks.-The diurnal inequality of temperature in the underground chamber is negligible and the change in 24 hours seldom exceeds 0°.3 F. The annual range amounted to 11°3 (F) in 1924 and 11°9 (F) in 1925. Changes of humidity are at times considerable; as, for example, from November 12d 17h to 13d 16h when the relative humidity decreased from 77% to 43% in response to a fall in the open air from 90% at 12d 15h to 38% at 13d 4h.
In the following table the mean monthly temperature and humidity in the Underground Chamber are compared with the temperature and humidity in the open air. As the air in the Underground Chamber is always still, humidity tables for calm air have been computed and used for obtaining the relative humidity from the readings of the dry and wet bulb thermome-
ters.
Mean Monthly Temperature and Relative Humidity in the Underground Chamber and in the Open Air, during the year 1925.
In Underground Chamber.
In Open Air.
Month 1925.
Excess of Under- ground Chamber over Open Air.
Temper- Relative Temper- Relative Temper- | Relative
ature Humidity ature
Humidity ature Humidity
O
January,
71.6
56.8
February,...
69.3
56:0
March,
68.9
637
April,
69.1
65.2
83
May,
72'9
95
June,
76:4
96
July,
79'0
98
82 3
August,
80.0
82.5
79
September,. 80'2
814
74
October,
79'1
66
75'4
64
November,.. 77.6
65
71.9
December,.. 74.5
+7
62'9
58
Range 113
SI
26'5
27
++++
O
4
8
%
II
3.3
16
5.2
3.9
4'5
+10
4'7
+14
3.5
+I,
2.5
+15
1.2
+ 3.7
+ 5'7 +116
—
2
5
I!
No comments yet.
Private notes are available after approval.