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British Rainfall 1867 page 10
self sees their fallacy, and points out some of their
faults; but, though experiments, on a limited scale, have
been tried from time to time, the question has never been
fairly grappled. Good suggestions have been dropped here and
there; and, before anything is actually commenced, all
previous experiments - those of Dalton, Charnock, Daniell,
Howard, Miller, Buist of Bombay, Golding of Copenhagen,
Haughton of St Helena, and others, must be reviewed.
It appears to me that a rather troublesome and costly
process is necessary before we can at all presume to decide
on any instrument for general use, and that it should take
the form of a series of experiments, with compartments of a
cubic yard each, sunk in the ground, waterproof, funnel
shaped at the bottom, with taps and cans. The simplest mode
of carrying it out would probably be to cut a trench about
30 ft. long, and 6 ft. deep, in a spot where perfect
drainage could be secured, and then form the cubes in
brickwork, lined with Portland cement, leaving a sunk path
in front, to give access to the cans, as shown in the
section of one. The cubes could be filled with various
substances; and by their modification, and at one time
leaving the taps (C) open, and another closing them - by
leaving them with no water but the rain, and at other times
keeping their contents in a state of saturation, we should
not only go far beyond anything that has been done before,
but should probably be led to some simple form of instrument
which, even if not itself correct, might bear a known
per-centage of error, and be available for differential
results.
Wherever these or similar experiiments are tried, a regular
record must be kept of the dry and wet bulb thermometers,
and it may also be expedient to try the self-registering
hygrometers invented by Mr. Vivian, of Torquay, and
exhibited at the Oxford meeting of the British Association.
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