Jacques Wardlaw Redway

“ The specific locality sometimes requires its own rain measurements. A rain gauge of the Weather Bureau pattern is useful, but a metal container with straight sides will answer fairly well, and an inch rule will answer the purpose of a measuring stick. The volunteer observer who studies the rainfall of a locality may thus gain the essential information required; namely, the minimum amount of rain, and also the optimum rainfall both as to amount and distribution, for a specific crop. ”

“ The wind is the chief obstacle to accuracy of rainfall measurement and shielding the gauge from the full strength of the wind is the best means to insure an accurate catch. The Nipher shield is a trumpet-shaped metal device about 20 inches across which surrounds the mouth of the gauge. ”

“ In suburban localities and in communities where buildings are 100 feet apart the gauges are better placed in such positions as have the full sweep of the rain-bearing winds. If two places 100 feet or more apart show no material difference in the catch, either location is probably suitable. With gentle rain and still air the two gauges should be in close agreement; if the wind blows in strong gusts there may be a material difference. ”

“ A gauge 40 inches high with an interior diameter of 10 inches provided with a Nipher shield, is used at the station where not less than two observations a day are made. The accumulation of snow is weighed from time to time on a spring balance, the dial of which reads hundredths of an inch instead of ounces. A mechanical device lifts the receiver from its support so that it can be readily removed to the swinging arm that carries the balance. ”

“ A pit and ring of concrete with a movable cover of wire mesh, coarse enough to permit rain to enter without obstruction and fine enough to keep leaves out makes an ideal position for a rain gauge in an open and fairly level country. ”

“ In California, however, the floods of the Sacramento and San Joaquin River valleys are largely predetermined by the snowfall in the mountain slopes to the eastward; and in many arid regions the crop production which depends on irrigation must be foretold mainly by the total of snowfall. ”

“ In the case of the first three, the observer may remove the receiver and tube from the gauge and catch the precipitation in the barrel. In the last case about the only way to overcome the difficulty is to make a considerable number of measurements where no drifting is apparent. One must use care to avoid measuring old snow with a fresh fall. ”