Weather Signs, and Protection from Frost. 159 



To Predict Frost (Kedzie). 



1. When the sunshine is very hot and the shade very 

 cold and the shadows very deep, "there is frost in the air," 

 because the air is very dry and radiation of heat little checked. 



2. When the dew point is more than 10 F. above frost 

 point, there is little danger of frost. To find approximately 

 the temperature of dew point when the temperature of the air 

 is between 45 and 65 F. , multiply the difference between the 

 wet-bulb and dry-bulb thermometers by two and subtract the 

 product from temperature of dry-bulb. If the remainder is 

 above 42 F., there is little danger of frost. The nearer this re- 

 mainder comes to 32, the greater the danger of frost, espe- 

 cially if the air is still and clouds disappear at sunset. 



T. Protect Plants from Light Frosts. 



1. Make a smudge in the garden or vineyard at night when 

 the frost is expected. Rubbish or litter and tar make the best 

 smudge. 



2. Syringe the plants thoroughly at night-fall. 



