The Ohio iJSCaturalist, 



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 Minmum Temperatures for Frost Protection 405 



ScHAFFNER— A Preliminary Survey of Plant Distriljution in Ohio -409 



GoRMLEY— The Roses of Ohio 419 



ScHAFFNER— New find Rare Plants Added to the Ohio List in 1914 432 



Rice— The Ohio Academy of Science 433 



McAvoY— Meeting 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 jDrogressive 

 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 ininimum 

 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 detennine 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 

 infonnation to a large number of places in the State where heating 

 is practiced. 



405 



