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THE ESSEX FIELD CLUB.
guarantee these observations will all be going on next year; therefore one
welcomes what at first sight might appear an unreasonable number of observers,
because even if you have three in a town, two out of the three, or even all three may
from one cause or another disappear, and the consequence is that it is not easy to
have too many, because you will readily understand that the first thing one wants in
meteorological work is continuity. I could illustrate that perhaps as well by
one fact upon which I shall have to say something, as in any other way, and that
is the question of the deficient water supply which has occurred in some parts
of Essex, I believe, even up to the present time, and which was produced by the
drought of last year. But was 1887 one of those exceptionally dry years which is
going to turn up only once in a century ? Nothing of the sort! I have all the figures
here, and have made a little table which some day may appear in the Essex
Naturalist. Many persons fancy that 1887 was something unprecedented as
a dry season; it was so in other parts of the country, but not so in Essex.
And therefore if there is, as I am told is the case, a deficiency in the quantity
of water in a good many of the Essex wells, it is due to the distribution of
the rainfall rather than to the total amount during the year.
Now, with respect to the measurement of rainfall, I said that it was an
extremely simple operation, and I think I shall convince you that there is
not only no one in this room who could not do it, but that you could hardly
find a housemaid who would not make a first-rate observer. It is simply a
case of a little patience and trial. I have not brought a rain-gauge with me,
but I think we can do nearly as well without. Most of you know what
a funnel is, and a funnel and a bottle make a rain-gauge with the single exception
of the measure. The essential feature of a rain-gauge is the funnel, which is to
be placed near the ground—about a foot above it. It must be level, and should
be quite unsheltered by trees or houses. That funnel naturally collects the
rain which would have fallen on the little bit of ground over which it is standing ;
the water passes down it into the bottle, and in a well-constructed rain-gauge no
evaporation of the rain can take place when once it gets there. It is in fact
a rain trap ; the water is caught, and stops there until it is measured.
As to the patterns of rain-gauges and where to buy them, I must be cautious
in what I say, for there is considerable jealousy among the manufacturers, and
I am almost certain to be accused of favouritism by some one. As, however,
I have never patented any pattern of rain-gauge, I may be credited with
a certain impartiality in discussing the subject, and I will leave the field open to
all, only giving a few hints to guide you in your choice.
Upon one point it is necessary to be despotic, viz., that amateurs should never
try to make their own gauges ; if they do, they are almost certain to go wrong in
some respect, and nothing is more vexing, both to the observers and to myself, than
for it to be discovered after observations have been recorded for a long time that
the labour of years has been vitiated by the use of an inaccurate instrument.
For use in ordinary localities I think that the annexed (Fig. 1) is the best
pattern; it is known as the Snowdon gauge; it is five inches in diameter, is
easily fixed by four stakes, as shown; the 'glass jar, each division on which
denotes 1/100th of an inch of rain, when filled up to the top division holds
0.50 in., or half an inch; the bottle holds about three inches of rain, and
of course, in the very rare case of the fall exceeding that, the excess is
saved by the can, and must be carefully measured. A rain-gauge should not
be set on a slope or terrace, but on a level piece of ground, at a distance