422 ReEpoRT OF THE HORTICULTURAL DEPARTMENT OF THE 
point, the temperature, and the motion of the air. Of the several 
methods used in protecting orchards against frosts, two commend 
themselves to the fruit-grower of this region; namely, one based 
on the warming of the air, and the other on the production of a 
dense cloud of smoke. 
Small fires placed at proper intervals have been found capable 
of raising the temperature of an orchard several degrees. Wire 
baskets several feet above ground holding coal or wood have been 
found the most efficient, though torches, oil pots, and other such 
devices have been used advantageously. From twenty to forty 
Gres [per acrevare- required: 
Smudging is cheaper but less effective, chiefly because the smoke 
is too often carried out of the orchard by winds. Prunings, straw, 
manure, litter of all kinds, tar and crude oil have been used for 
smudging. In the case of the first named materials the burning 
litter is moistened as it burns thus producing a dense, steamy 
smoke which acts as a screen to prevent loss of heat by radiation; 
the heat of the fire raises the temperature somewhat, and the 
smoke may also screen the plants from the sun in the early morn- 
ing. This method of frost-fighting is in use in some of the vine- 
yards of New York. | 
In concluding this topic it must be said that methods of fighting 
frosts are still uncertain and in the experimental stage — especially 
in New York. The several proprietary compositions for burning, 
and the devices for making and distributing smoke, manufactured 
in European countries, but now being offered in America, have 
not been thoroughly tried in this country, and since tests seem to 
show them of doubtful utility abroad, both because of lack of 
efficiency and cost, they may well be left alone for the present in 
this State. 
The importance of the average date of the last killing frost in 
spring to the fruit-grower, has been noted. Table II gives this 
information for New York. The records of killing frosts in 96 
‘stations in the State were used, and for the years 1897 to 1906 
inclusive, in preparing the table. 
By killing frost is meant one which causes the death of the 
tender vegetation of the plants ordinarily cultivated in the region 
under discussion. It is generally considered by phenologists that 
the last killing frost more than any other weather event, character- 
izes the advent of spring. Consideration will show that the fruit- 
grower as well as the phenologist must accept the last frost as 
