THE ESSEX FIELD CLUB.
95
work. The general public have an idea that if they buy a barometer, and,
perhaps, a couple of thermometers, they will know what weather is about to
prevail next day and the day after that, but in that impression I do not at all
agree. I have had something over thirty years' work at meteorology and
weather observations, but I am quite sure that I don't yet know half as well as
the ordinary sailor does what weather is coming. The fact is meteorological
prediction can only be properly accomplished by the aid of those charts and maps
which you see in the newspapers. The barometer at one place may be going up
or down, and that is all you can determine by yourself from the barometer that
you have bought, but the meaning of the rise or fall can only be ascertained by
comparison with what the barometer is doing at other places ; and consequently
I should be sorry for anyone to run away with the idea that because they buy a
barometer and some thermometers, and because they observe them regularly every
morning at nine o'clock, and every evening at nine o'clock, they will be able
to foretell what the weather will be. I believe they would know a great deal
more if they left their instruments alone and looked at the clouds and the
sunsets for inspiration as to the coming weather changes. But there is a
further aspect of the case; climatical reports are required for medical men and
for other purposes. Now it is a curious thing, which I cannot quite
account for at the present time, that there is not a single climatical station in
Essex. I believe this is the only county in England which does not contain
a single climatical station. The expense for a climatical station is much more
than for a rain-gauge, but it is not serious by any means. You require
what is known as a Stephenson Screen. The original arrrangement was I believe
made from a meat-safe, and the screen is certainly strongly allied to the meat-safe
in its general appearance. It is a square box made with sides something like
Venetian blinds, and thermometers are placed inside that. You require the screen
which costs about £2, and four thermometers which cost about £1 each, so you
have altogether £6 for that, and these with your rain-gauge will complete your
equipment. The thermometers you have inside are the maximum and the
minimum—the dry and the wet—bulb thermometers; and having these your
station is completely equipped. You will have noticed that I have said nothing
about a barometer, and I have done so for this reason, that the barometer is not
essential for climatical purposes. The changes of the barometer do not affect the
public health to anything like a sufficient extent for it to be necessary for that
purpose. Of course, if it marks a change of several inches in air pressure you
would have results worthy of note, but short of so large a change as that there is
no need of it for purely climatical purposes. The barometer is of more service
in another way, and I should strongly recommend it to the members of the club
if they are interested in knowing the relative heights of different places.3 The
Aneroid Barometer has had a large amount of abuse, but I for one have always
stood up most strongly in its favour. They are extremely portable, and very
reliable if reasonably well looked after.
Ere concluding I may tell you that when thinking about what I was going to
say to-day, I called to mind the name of a man who was almost the first, certainly
the second, observer in this kingdom of rainfall, and he was an Essex man.
allude to the Rev. Wm. Derham, of Upminster. He was born in 1657, and
3 Pocket Altitude Tables, containing short and simple rules for accurately determining altitude
barometrically, have been prepared by Mr. Symons, and can be obtained at 2S. 6d. post free, 011
application to him at 62, Camden Square, London, N.W,—Ed.