Foretelling Frosts. 121 
vens, on the same occasion, reports success in sav- 
ing orange trees from cold by burning rosin, secur- 
ing both heat and smoke. -He makes cones six 
inches high and six wide of common hardware paper 
which has received a coat of paint. These cones 
are filled with cheap rosin and set near the trees. 
A little of the rosin is pulverized on top, and it 
is then set on fire from a bit of oiled waste which 
is dropped on it. Six pounds of rosin burn about 
an hour. 
THE PREDICTION OF FROST. 
In considering the means of predicting frost, it 
is first of all important that the student should ob- 
tain a clear idea of the usual or average dates of 
the opening and closing of the seasons of his locality. 
Records made by himself upon his own farm from 
year to year are invaluable. He may derive very 
much help, also, from the records of meteorological 
bureaus. A general tabulation of spring and fall 
seasons (see pages 123 and 124) may be suggestive 
in this connection :* 
“The data for the accompanying tabulation of 
the killing frosts of the region east of the Rocky 
Mountains was compiled from the bulletins and an- 
nual reports of the United States Weather Bureau. 
The table is divided into dates for spring and fall, 
and these in turn into earliest, latest, and average 
*\ade by Alexander D. MacGillivray, Assistant in Entomology, Cornell Uni- 
versity. 
