X.---Sea.
1. The direction from which the waves of the sea come should be registered. If there are swells from other quarters they should be also registered.
2. The disturbance of the sea should be noted in figures -
0. Calm.
1. Very smooth.
2. Smooth.
3. Slight.
4. Moderate.
5. Rather rough.
6. Rough.
7. High.
8. Very high.
9. Mountainous.
XI.-Time of Observation.
1. The hours of observation adopted in tropical regions are 10a, 4p and 10p (local mean time), which must be adopted at all stations for the sake of uniformity. From readings taken at these hours a near approximation to the average values of the meteorological elements can be deduced.
The instruments are read in some Chinese harbours and lighthouses every three hours beginning with midnight. If made in an honest and careful manner such registers are most valuable.
At sea the instruments are read every two hours beginning with midnight.
During typhoons the readings may with advantage be taken every hour.
If from any cause a reading is taken either too early or too late, the precise minute at which it was taken should be entered.
If a reading has been omitted, a line should be drawn in the space for it. A gap is better than a deceptive entry.
In case the observer is himself unavoidably prevented from making the observation at the proper time, he may entrust some other competent individual with making it, but the name of the observer should then be stated at every observation made by him.
2. The order in which the entries are generally made is as follows:-
AT 10 A. AT 4 P. AT 10 P. Attached thermometer. Attached thermometer. Attached thermometer. Barometer. Barometer. Barometer. Dry bulb thermometer. Dry bulb thermometer. Dry bulb thermometer. Damp Damp » Nebulosity. Nebulosity. 55 Form of clouds. Form of clouds. Form of clouds. Direction whence coming. Nebulosity. Direction whence coming. Wind direction. Direction whence coming. Wind direction. force. Wind direction. force. Weather now. force. Weather now. since last. Weather now. since last. since last. Duration of rain. Duration of rain. Sea direction. Sea direction. disturbance. disturbance. Amount of rain. Duration Sea direction. disturbance.Maximum thermometer.
Black bulb
Minimum
25
Minimum on grass.