150 (GARDENS AND THEIR MEANING 
construction of a simple apparatus for measuring rainfall. 
The purpose is obviously to measure the depth of the sheet 
of water that would lie on level ground after a rain, suppos- 
ing that none of the water were lost by evaporation or by 
soaking into the soil. This is done at experiment stations by 
exposing a cylindrical vessel, or rain gauge, to the storm, and 
measuring the depth of rain or snow that it receives. A good 
gauge should have a circular rim and a diameter of at least 
five or six inches. The edge should be sharp, with a vertical 
face on the inside. This gauge should be placed in a level 
and open space, some distance, if possible, from trees and 
buildings (a distance at least twice their height is the rule) ; 
then it should be fastened in place, to avoid being blown over 
by the wind. The rim should stand a foot above the ground, 
and should be carefully leveled. A movable funnel is generally 
placed within the gauge, so as to protect the water that lies 
beneath it from loss by evaporation. 
At a station the measurement of the amount of rain col- 
lected is usually taken by pouring the water from the gauge 
into a measuring tube of a certain smaller diameter, so that its 
area shall be one tenth of that of the gauge. The water then 
rises in the tube to ten times the true depth of the rainfall. 
This magnified depth is then measured by a graduated stick, 
the record being made to a hundredth of an inch. Record 
should be taken, if possible, at the close of every storm and 
always once a day, although some observers measure the 
rainfall only at a certain hour each day, without regard to 
the time when the rainfall ceased. The amount measured 
should always be entered in the record book before the 
measuring tube is emptied. Just here the hint of an expert 
gardener may well be followed. " Buy a barometer,” he says. 
” By obeying a few simple rules you will be able to forecast 
the weather.” 
