285
15. Mr. J. I. PLUMMER determined the time, attended to clocks, chronometers, chronograph and time-ball and reduced transit observations, Mr. F. G. FIGO issued weather-forecasts and storm- warnings, drew storm-tracks, and made magnetic observations. Miss DOBERCK attended to marine meteorology, and the native assistant, under close supervision by Mr. FIGG and myself, attended to the meteorological instruments and the construction of meteorological tables, assisted by the native staff of computers and telegraphists.
16. The cisterns of the barograph and standard barometers are placed 109 feet above M.S.L. The bulbs of the thermometers are rotated 108 feet above M.S.L., and 4 feet above the grass.
The solar radiation thermometer is placed at the same height. The rim of the rain-gauge is 105 feet above M.S.L., and 21 inches above the ground.
17. The monthly Weather Reports are arranged as follows:-
Table I. exhibits the hourly readings of the barometer reduced to freezing point of water, but not to sea level, as measured (at two minutes to the hour named) from the barograms.
Tables II. and III. exhibit the temperature of the air and of evaporation as determined by aid of rotating thermometers. Table II. exhibits also the extreme temperatures reduced to rotating ther- mometer by comparisons of thermometers hung beside them. Table III. exhibits also the solar radia- tion (black bulb in vacuo) maximum temperatures reduced to Kew arbitrary standard.
Table IV. exhibits the mean relative humidity in percentage of saturation and mean tension of water vapour present in the air in inches of mercury, for every hour of the day and for every day of the month, calculated by aid of Blanford's tables from the data in Tables II. and III.
Table V. exhibits the duration of sunshine expressed in hours, from half an hour before to half an hour after the hour (true time) named.
Table VI. exhibits the amount of rain (or dew) in inches registered from half an hour before to half an hour after the bour named. It exhibits also the estimated duration of rain.
Table VII. exhibits the velocity of the wind in miles and its direction in points (1-32). The velocity is measured from half an hour before to half an hour after the hour nained, but the direction is read off at the hour.
Table VIII. exhibits the amount (0-10), name (Howard's classification) and direction whence coming of the clouds. Where the names of upper and lower clouds are given, but only one direction, this refers to the lower clouds. With regard to the names of clouds: nimbus (nim) is entered only when the rain is seen to fall; when no rain is seen to fall cumulo-nimbus (cum-nim) is entered. This name indicates clouds intermediate between cum and nim. Cumulo-stratus (cum-str) is the well-known thunder cloud, while strato-cumulus (str-cum) signifies a cloud intermediate between stratus and cum. Sin-cum means alto-cumulus.
Table IX. exhibits for every hour in the day, the mean velocity of the wind reduced to 4 as well as 2 directions, according to strictly accurate formula, and also the mean direction of the wind.
Below this is printed a list of the phenomena observed.
18. The following annual Weather Report for 1898 is arranged as follows :-
Table III. exhibits the mean values for the year (or hourly excess above this) obtained from the monthly reports. The total duration of rain was 809 hours. There fell at least 0.01 inch of rain on 141 days.
Table IV. exhibits the number of hours during a portion of which at least 0.005 inch of rain (or dew) was registered.
The
Table V. exhibits the number of days with wind from eight different points of the compass. figures are obtained from the mean daily directions in Table VII. of the monthly reports. Days with wind from a point equidistant from two directions given, are counted half to one of these and half to the other, eg, half of the days when the wind was NNE are counted as N, and the other half as NE. Table VI. exhibits the number of days on which certain meteorological phenomena were regis- tered, and also the total number of thunderstorms noted in the neighbourhood during the past year.
Table VII. shows the frequency of clouds of different classes.
Table VIII. is arranged as last year.
Table IX. exhibits the monthly and annual extremes.
Table X. contains five-day means.
I have the honour to be,
Sir.
Your most obedient Servant,
The Honourable
THE COLONIAL SECRETARY,
&C.,
gc..
&c.
W. DOBERCK,
Director.