FROST RESISTANCE OF EUCALYPTUS IN CALIFORNIA 413 



devices used to raise temperature in the citrus groves. Near Pomona 

 orange trees vi^ere constantly sprayed with water, and ice formed as it 

 fell. Ice 3 inches deep formed in a watering trough north of the city 

 of San Bernardino, where in 30 years there had never been more than 

 a thin film of ice which melted during the day. 



TEMPERATURES 



Low temperatures in different localities within the affected area 

 varied somewhat, as is indicated in the following table. The figures 

 given are taken in part from the Monthly Weather Review and in part 

 from apparently reliable observations by private individuals. Consid- 

 erable discrepancy sometimes occurred in the records from the two 

 sources, due probably for the most part to differences of exposure and 

 to lack of thermometer shelters in the observations not taken by the 

 Weather Bureau. In each case that figure has been selected which 

 appears to indicate at all accurately the lowest temperature to which 

 the trees were actually exposed. 



Table i 



Day of month, January, 1913 

 Location 4567 8 



Minimum temperatures, degrees Fahrenheit 



, ^ ^ 



San Bernardino 22 26 18 18* 19* 



Redlands 24 22 18 18* 24* 



Riverside 21 18 18 19 22* 



Del Rosa 24 26 17 14 21 



Colton 28 22 18 19* 27* 



Highland 22 16 16 23 



Etiwanda 20 19 17 



Rialto 30 26 23 24 



Beaumont 29* 20* 16* 24* 32* 



Banning 24 21 16 I2(?) 



Ontario 26 25 20 27 



Pomona 28 25* 20 18* 22* 



Monrovia 26 28* 23 18* 19* 



Covina 22 23 22 21 24 



Santa Ana 24 25 24 24 



Los Angeles 32 31 26 18 36* 



Pasadena 29 31* 25* 21* 25* 



* These figures arc based on Weather Bureau records. 



The following minimum temperatures during the January. 1913. cold 

 spell were given by persons living at or near the places mentioned, but 

 the reliability of the record cannot be vouched for because of the poor 

 grade of thermometers in general use. The figures in the temperature 

 columns indicate the number of times that the temjierature at the top 

 was noted in the locality : 



