94
THE ESSEX FIELD CLUB.
that into the funnel; that will melt the snow and take it all down as water ; then
deduct the amount which you have added as warm water, and the difference
between that and the total will be the snow. Another good plan is simply to
take the funnel off the bottle, invert it in the snow, turn it round, and you will
find that you can lift a complete cylinder of the snow, and you will then be able
to see what you have got. A further rule is to measure a vertical depth of
snow. Snow differs in its density; I have measured snow so dense that four
inches of snow would give an inch of water, and snow so light that thirty-
three inches only made one inch of water, and therefore it is difficult by the
mere measurement of depth to know what quantity you have got. It is always
desirable to measure that in the gauge, and also to take a cylinder up and
measure that. Roughly speaking, snow is on the average just one-twelfth of the
density of water, that is to say a foot of snow will give you an inch of water.
But the method of measuring the depth of the snow, to determine the amount of
water present, is a very rough one, and should not be adopted excepting in cases
of necessity.
There is now, I think, but one other point to be noticed ; one that will persist in
coming into everything connected with accurate scientific research, and that is the
money question. You may want to know what a rain-gauge costs, and what
would be the expense attending the making of persistent and useful observations
on the rainfall of your respective neighbourhoods.
Rain-gauges cost from 10s. 6d. to £1 1s. each, according as they are made of
japanned tin, of galvanized iron, or of copper, and the makers generally charge
about 1s. 6d. for a packing case to send it home in. The pattern I recommended
and figured above, the "Snowdon Rain-gauge" can, no doubt, be obtained from
any optician, but it may be convenient to give, in alphabetical order, the names and
addresses of a few of the principal makers:—Casella, L., 147, Holborn, E.C.;
Hicks, J. J., Hatton Garden, E.C.; Negretti and Zambra, Holborn Viaduct and
Cornhill, E.C.; Pastorelli, F., 10, New Bond Street, W. There is one point to
be observed, and that is — wherever, and of whomsoever, rain-gauges may be
bought it is very desirable that the purchaser should insist upon having
certificates of their accuracy. Rain-gauges are examined, and certificates
issued, by Kew Observatory, and by myself, the charge in each case is the
same, namely, 2S. 6d. Roughly speaking, therefore, you may take it that about
17s. or 20s. will provide you with a gauge all complete, and sufficient for all
ordinary observations. As I hinted above it is desirable to have a second
gauge of greater capacity for the purpose of checking the records, but even in
this case the outlay would not be very alarming, and with care well-made gauges
will last a long time. The only other expense is the very trifling one of some
form of register in which to record your observations [already referred to on page
92.—Ed.].
Now we have to consider the practical results obtainable from meteorological
observations, and I am afraid that I should give vent to some rather heretical ideas
if I were to tell you exactly what I thought of such matters. Weather observations
can be divided into two branches, or, perhaps, more. First of all we have the very
practical one with respect to our wells, springs, and river supplies, and then we have
what I may call climatical observations which afford information as to the relative
advantages of different health resorts, the times at which it is good to sow
or to reap, or to go to Brighton, or to Lowestoft in search of fresh air and fine
weather, and various considerations of that sort. That is what I call climatical