105
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 hour named.
It ex- hibits also the observed 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 named, 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-nin) is entered. This name indi- cates 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. Sm-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 formulæ, 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 1903 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 773 hours. There fell at least 0.01 inch of rain on 135 days. Table IV. exhibits the nuinber 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 registered, and also the total number of thunder- storms 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.
19. 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 ELLIOT BROTHERS No. 55. The dips were observed with dip-circle Dover No. 71.
The methods adopted in making observations and in determining and applying the corrections are explained in Appendix G of Observations and Researches made in 1885-"On the verification of the unifilar magnetometer ELLIOT BROTHERS No. 55." The value of log K determined during the year, was 3.44914 at 25°.
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The value of I was 6.10. The mean value of the magnetic moment of the vibrat- ing needle was 574.91.