92
THE ESSEX FIELD CLUB.
The observations should be taken each morning, sometime between 8 and
9 o'clock, and the amount measured at 9 a.m. on any day should be set against the
previous one ; because the amount registered at 9 a.m. of, say the 17th, contains the
fall during 15 hours of the 16th, and only 9 hours of the 17th. All columns of
figures of observations should be cast twice—once up and once down, so as to
avoid the same error being made twice. Never copy a total, always cast the
column afresh. When there is no rain, a line should be drawn rather than cyphers
inserted.
When very heavy rains occur, it is desirable to measure immediately on their
termination, and it will be found a safe plan after measuring to return the water
to the gauge, so that the morning registration will not be interfered with. Of
course if there is the slightest doubt as to the gauge holding all that falls, it must
be emptied, the amount being previously written down.
In view of any unavoidable absence every observer should train some one as an
assistant; but where this is not possible, instructions should be given that the
gauge be emptied at 9 a.m. on the 1st of the month, and the water bottled,
labelled, and tightly corked, to await the observer's return.
Hardly a year passes in which some of our observers do not allow their gauges
to overflow, it is therefore necessary to call attention to the fact that there does not
seem to be any part of the British Isles where 4 inches may not fall in 24 hours.
It is not desirable to purchase any guage of which the capacity is less than
4 inches.
Each observer should decide upon a specific name for his station, and notify
immediately to the general recorder any change in the position of the gauge or
the discontinuance of his record. Old established gauges should not be moved,
nor their registration discontinued until, at least, two years after a new one has
been in operation, otherwise the continuity of the register will be irreparably
destroyed. Both the old and the new ones must be registered at the same time,
and the results recorded for comparison.
It is desirable, but not indispensable, that observers should have two gauges,
and that one of them should be capable of holding 8 inches of rain. One of the
gauges should be registered daily, the other weekly or monthly as preferred, but
always on the 1st of each month. By this means a thorough check is kept on
accidental errors in the entries, which is not the case if both are read daily.
Observers having two gauges and recording both daily, should keep the records
distinct, and forward a copy of each to whoever has undertaken the task of
collating the records for the county or district. Never take a mean of the two
series of observations.2
Everyone will admit that to make and record the above described observations
is not a very serious undertaking; it comes always with one's breakfast. At the
end of the month whoever makes these observations, makes a copy of them, and
sends them off to, we will say, the Secretary to the Essex Field Club, and the
2 For the convenience of observers, Mr. Symons has drawn up a set of blank forms, diagrams,
etc., as follows :—
Any of these will be sent, post free, at the prices named, on application to Mr. G. J. Symons,
62, Camden Square, London, N.W.—Ed.