Sessional_Paper_1889 — Page 138

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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 in inches registered from half an hour before to half an hour after the hour named.

Table VII exhibits the velocity of the wind in miles and its direction in numbers. The velocity of the wind is measured from half an hour before to half an hour after the hour named; but the direction is read off at the hour except when it is very light and changeable, in which case the average direction during the hour is estimated, taking into account the velocity from different quarters. The direction is not noted when the velocity is below 1.5 miles an hour. The vane is to be depended on except when the velocity is uniform (which is of course a rare occurrence) and below 3 miles an hour.

Table VIII exhibits for every hour in the day, the mean velocity of the wind reduced to 4 and also to 2 directions, as well as the mean direction of the wind :-

The number of miles traversed by winds from directions 31, 32 and 1 and half the number of miles from 30 and 2 are termed (N.) The number of miles from 3, 4 and 5 and half the number of miles from 2 and 6 are termed (NE), etc. We have thus :—

N=(N) + (NE) cos. 45° + (NW) cos. 45°

E=(E) + (NE) cos. 45° + ( SE ) cos. 45°

which are the components exhibited in this table.

etc.

Table IX exhibits the direction (to two points) and force (0-12) of the wind estimated at Victoria Peak and the rainfall measured at 10a. and entered to preceeding day at the Peak and at the Observatory, as well as the duration of rain estimated at the Observatory.

Table X exhibits the readings of the barometer reduced to freezing point of water but not to sea level, and of the thermometers at Victoria Peak.

Table XI exhibits the relative humidity and tension of vapour at 10a., 4p. and 10p. daily at the Observatory and at the Peak.

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Table XII exhibits the amount (0-10), name and direction whence coming of the clouds. Where names of upper and lower clouds are given, but only one direction, this refers to the lower clouds. These observations are made with the unaided vision. BRAUN's nephoscope, which has lately been again brought out in Sweden, has not been used.

29. The following annual weather report for 1888 is arranged as follows:-

Table III exhibits the mean annual values (or mean hourly excess above this) obtained by aid of the mean values printed in the monthly reports. The mean hourly intensity of rain is obtained from the sixth table of the monthly reports in connection with the fourth table of this report. The total amount of rain measured daily at 10a. was 104-585 inches at the Observatory and 111·17 at the Peak. The total duration registered at the Observatory was 854 hours. The rainfall was at least 0.01 inch on 173 days at the Observatory, and on 111 days at the Peak.

The excess of the black bulb above the air maximum is given as usual. It would have been much better to compare the former with the temperature registered at noon, but that is not done elsewhere.

Table IV exhibits the number of hours during a portion of which rain was registered.

Table V exhibits the total distance traversed by as well as the duration and average velocity of winds from bi-quadrantal points, obtained from the tables published on the first page of each monthly weather report.

Table VI exhibits the number of days on which certain Meteorological phenomena were noted and also the total number of thunderstorms observed in this neighbourhood during the year.

Table VII shows the frequency of clouds of the different classes.

Table VIII exhibits the values of different quantities as explained in previous reports. The hourly intensities of rain have been obtained from the data in the ninth table of the monthly reports.

Tables IX and X exhibit the monthly and annual extremes. The extremes of humidity and vapour tension have been obtained from the eleventh table of the monthly reports and are therefore as usual not quite complete as the values for only 10a. 4p. and 10p. daily are calculated.

Tables XI and XII are arranged as explained in the report on five-day means for 1886,