LOCATION OF THERMOMETERS
1. They must be properly exposed.
2. A good circulation of air around them is necessary.
3. They must be properly protected from the rays of the sun.
Note: If these instructions are not carefully followed out, errors are apt to occur, and you will be misled.
For a change of wind towards northerly directions, a thermometer falls. For a change of wind toward southerly directions a thermometer rises.
Fig. 50
GILBERT RAIN GAUGE