i 
H, A. Hazen—Thermometer Exposure. 377 
The mean results in Table V show nearly identical air tem- 
peratures by the three methods, but a relative humidity more 
than 16 per cent too high for “ Russian” and over 7 per cent 
for “ Pattern.” : 
The following conclusions are advanced : 
Ist, Thermometer shelters when exposed to direct sun heat 
should be at least 36” long. 
» With proper precautions the thermometer “ fronde” 
both dry and wet will give the most correct air temperature 
and relative humidity. 
3d, The interposition of a second louvre seems hardly neces- 
Sary; 1t not only prevents the free access of air, but also if 
ventilation is used it must affect the air which is propelled to 
the thermometer. . 
_ 4th, While the thermometers in a single louvred shelter may 
in heavy storms be wet, yet it takes but a moment to wipe the 
bulb dry, besides in rainy weather both dry and wet indicate 
nearly the same temperature. 
th, For obtaining even approximate relative humidity in 
calm weather single louvred shelters are necessary, and for the 
best result an induced air current is essential especially in the 
; cared in northern countries, 
t the same time that the above experiments were being 
made without artificial ventilation. As many are not in a 
situation to use any but a window shelter the following sug- 
8estions are added for places north of 35° lat. N. 
