149
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 formulæ, and also the mean direction of the wind.
Below this is printed a list of the phenomena observed.
15. The following annual Weather Report for 1900 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 838 hours. There fell at least 0.01 inch of rain on
140 days.
Table IV. exhibits the number of hours during a portion of which at least 0.005 inch of rain (or dew) was registered.
Table V. exhibits the number of days with wind from eight different points of the compass. The 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, e.g., 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,
16. The observations of magnetic declination and horizontal force published in Tables XI. and XII. were made with magnet. No. 55 on Kew pattern unifilar magnetometer Elliott Brothers No. 55. The dips were observed with dip-circle Dover No. 71.
The methods adopted in making the observations and in determining and applying the correc- tions are explained in Appendix G. of Observations and Researches made in 1885: "On the verifica- tion of the unifilar magnetometer Elliott Brothers No. 55." The value of log K was 3.44907 at 25°. The value of P was+ 6.597. The mean value of the magnetic moment of the vibrating needle was 580.82.
The times of vibration exhibited in Table XII. are cach derived from 12 observations of the time occupied by the magnet in making 100 vibrations, corrections having been applied for rate of chrono- meter and are of vibration.
The observations of horizontal force given in Table XIII, are expressed in C.G.S. units. The vertical and total forces have been computed by aid of the observed dips.
I have the honour to be,
The Honourable
THE COLONIAL SECRETARY,
&c.,
Sr.,
&c.
Sir.
Your most obedient Servant,
W. DOBERCK,
Director.