An accurate rain gauge may be easily constructed from galvanized iron, as shown in the sketch herewith.
The funnel, A, overlaps and rests on the body, B, and discharges into the tube, C, the area of which is one-tenth that of the top of the funnel.
The depth of the water in C is thus ten times the actual rainfall, so that by measuring it with a stick marked off in tenths of an inch, we obtain the result in hundredths of an inch.
A good size to make the rain gauge is as follows: A, 8 in. diameter; C, 2.53 in. ; length of C, about 20 in.
It should be placed in an exposed location, so that no inaccuracy will occur from wind currents.
To find the fall of snow, pour a known quantity of warm water on the snow contained in the funnel and deduct the quantity poured in from the total amount in the tube.
Excerpt from the book:
THE BOY MECHANIC
700 THINGS FOR BOYS TO DO
WITH 800 ILLUSTRATIONS
1913, BY H. H. WINDSOR CHICAGO
POPULAR MECHANICS CO. PUBLISHERS