ORCHARD PROTECTION. 41 



reading. If this comes above thirty-two degrees there is no 

 danger of a frost, but if below there is danger, although frost 

 may not occur owing to wind, clouds or other phenomena. 



DEW-POINT TABLE. 

 Difference of 



reading of dry Temperature of Air in Degrees (Fahrenheit), 



and wet bulbs. 15 20 25 30 35 40 45 50 55 60 65 70 



1 ....".... 11 16 22 27 32 38 43 48 53 58 63 69 



2 6 12 18 24 30 35 41 46 52 57 62 67 



3 7 14 21 27 33 39 44 50 55 60 66 



4 1 10 17 24 30 36 42 48 53 59 64 



5 4 13 20 27 33 40 46 51 57 62 



6 7 16 24 30 37 43 49 55 61 



7 1 11 20 27 34 41 47 53 59 



8 5 16 24 31 39 45 51 57 



9 11 20 28 36 43 49 55 



10 4 16 25 33 40 47 53 



11 11 21 30 38 45 51 



12 4 17 27 35 42 49 



13 11 23 32 40 47 



14 5 18 28 37 45 



15 12 24 34 42 



First Example. 



Dry bulb thermometer 60 degrees 



Wet bulb thermometer 47 degrees 



Difference 13 degrees 



Dew point from table i 32 degrees 



Probably no frost. 



Second Example. 



Dry bulb thermometer 47 degrees 



Wet bulb thermometer 39 degrees 



Difference 8 degrees 



Dew point from table, between 24 and 31 or 27 degrees 

 Probably a severe frost. 



Protection from injurious spring and autumn frosts may be 

 given in various ways according to circumstances: 



(a) By covering up the whole plant and thus retarding its 

 period of bloom until danger of frost is past, as may be done 

 with strawberries and other small fruit. For this purpose they 

 may be covered with earth or mulch. Peach trees are some- 

 times covered with corn dtalks or hay to retard flowering. They 



