WEATHER IN CRANBERRY CULTURE 51 



is'none of the liquid in the small enlargement of the other end of the channel from 

 the bulb. The column must be restored if the liquid is separated in cither of these 

 ways. This is done readily by whirling the thermometer vigorously at the end of 

 a stout string of convenient length passed through the support holes in the other 

 end from the bulb. Care must be taken in doing this, for the instrument may 

 be a dangerous missile if it breaks away. 



Thermometer scales should be rubbed with ivory-black occasionally to con- 

 dition them for eas>- reading. 



Growers who wish to try their local weather data, where this is possible in the 

 formulas for computing minimum bog temperatures, should have dry-bulb and 

 wet-bulb thermometers, mounted in a shaded open-air porch or in a white- 

 painted wooden instrument shelter, to serve as a psychrometer. These may be 

 stationary, with a water cup and wick for the wet bulb, or be on a whirling 

 apparatus. The instrument shelter should be at a convenient height from the 

 ground for reading the thermometers and be 10 to 15 feet above the bog level. 



A table of dew-point temperatures, as published by the Weather Bureau, likely 

 to be useful to cranberry growers, is given here for convenience. 



