The Ohio £J\£a turn list, 
and Journal of Science 
PUBLISHED BY 
The Biological Club of the Ohio State University. 
Volume XV. JANUARY, 1915. 
No. 3. 
TABLE OF CONTENTS 
Smith— Predicting Min'mum Temperatures for Frost Protection.405 
Sch affner— A Preliminary Survey of Plant Distribution in Ohio.. 409 
Gormi.ey —The Roses of Ohio ... 419 
Schaffner —New and Rare Plants Added to the Ohio List in 1914.432 
Rice— The Ohio Academy of Science. 433 
McAvoy—M eeting of the Biological Club ... 436 
PREDICTING MINIMUM TEMPERATURES FOR FROST 
PROTECTION. 
J. Warren Smith 
(Professor of Meteorology, Columbus, Ohio.) 
The question of protecting fruit and truck crops from frost 
damage by building fires of oil, coal, or wood, is receiving consider¬ 
able attention in Ohio and some 40 to 50 of the most progressive 
fruit and truck men are now practicing orchard heating. 
The United States Weather Bureau has encouraged these 
efforts by establishing special frost-fruit stations for the purpose 
of studying local temperature conditions and for giving informa¬ 
tion as to the probable temperatures that may be expected on 
nights when frost damage is likely. 
It is known that fruit buds will stand lower temperatures at 
some periods of their growth than at others and that the minimum 
temperature will vary greatly under different topographic con¬ 
ditions. The ability to determine approximately the lowest 
temperature for any night when fruit buds or truck crops are in a 
critical condition will determine whether plans must be laid for 
starting the fires. 
The officials of the Weather Bureau by studying the approach¬ 
ing weather conditions from the daily weather maps and by a 
knowledge of the average daily range in temperature, the dew 
point temperature, and the varying temperature under different 
elevations makes very close temperature forecasts and sends this 
information to a large number of places in the State where heating 
is practiced. 
