Symons’s Rain Gauge resembles Howard’s, but has the advantage of having the glass receiver enclosed in a black or white japanned metal or copper jacket with openings permitting an approximate observation of the collected rain. The metal jacket is also furnished with strong iron spikes, which are firmly pressed into the soil, as shown at Fig. 49, thus ensuring perfect steadiness by its power to resist the wind. The graduated measure contains half an inch of rain (for a 5 inch circle) divided into 100ths.
50.
Symons’s Storm Rain Gauge.
Scale about 1/12.
Mr. Symons has devised another rain gauge of so ingenious and interesting a character that it needs only to become generally known among amateur meteorologists to be in universal demand. By its means an observer at a distant window may read off the rain as it falls. It is shown at Fig. 50, where the usual 5-inch funnel surmounts a long glass tube attached to a black board bearing a very open scale marking tenths of an inch in white lines; a white float inside the tube constitutes the index, which rises as the rain increases in quantity. If, as sometimes happens during a thunderstorm, the rainfall is excessive, a second tube on the left permits the measurement of a second inch of rain. It will be obvious that if the time at which the rain begins to fall be noted the rate at which it falls, as well as the quantity, is indicated at sight by this instrument.
51.
Beckley’s Pluviograph. Scale about 1/7.
Crossley’s Registering Rain Gauge has a receiving surface of 100 square inches. The rain falling within this area passes through a tube to a vibrating bucket, which sets in motion a train of wheels, and these move the indices on three dials, recording the amount of rain in inches, 10ths, and 100ths. Printed directions are furnished with each instrument, and the simplicity of the mechanism ensures due accuracy. A test measure, holding exactly five cubic inches of water, sent with each gauge, affords the means of checking its readings from time to time.
Beckley’s Pluviograph possesses the exceptional merit of recording with equal precision all rainfalls, from a slight summer shower to a heavy storm of rain. It may be placed in a hole in the ground, with the receiving surface raised the standard height of ten inches above its level.
Fig. 51 illustrates the construction of the instrument.
