66 



THE DATE PALM. 



TABLE 9. Sum of daily mean temperatures above 18 C. (64.4 F.) for fruiting period of 

 date palm from May 1 to October 81, at the stations named. 



i Until 1903 the temperature records in the Salton Basin were taken by voluntary observers from 

 thermometers exposed without proper shelters. Mr. Bernard G. Johnson, who lives in the Salton 

 Basin between Salton and Indio, Cal., writes as follows: 



" Formerly there were used cheap thermometers, placed at Indio in the shade of cottonwood trees, 

 at Salton under an overlapping roof, and at Volcano Springs under a roof that was but slightly over- 

 lapping. Now they have standard thermometers placed in regulation thermometer shelters, and 

 hence the difference." 



As might be expected, the older records taken at Volcano Springs proved to be much too high, at 

 Salton still too high, though somewhat nearer normal, and at Indio normal or somewhat too low 

 when compared with the records taken in 1903 with properly protected thermometers. 



Mr. Johnson queries: " If this year, for example, May was 8.3 degrees cooler than the average at 

 Volcano, why was it only 4 degrees cooler at Salton, 24 miles west of Volcano and at the level of the 

 valley, while it was 0.9 degree warmer 24 miles farther west at Indio? " 



Nevertheless, the sum of the daily mean temperature from May 1 for 1903 was still enough to 

 'mature the Deglet Noor date perfectly. 



A further proof of the greater sum of heat in the Salton Basin, as compared with the Salt River 

 Valley, is given by Mr. Johnson, who states that cantaloupes ripen at least fourteen days before the Salt 

 River Valley melons at Mesa, Ariz., and that, too, before the really hot weather begins, which occurs 

 about the first week in June. Mr. Johnson observes that if the same proportion continues, the grow- 

 ing season up to November 1 would give about six weeks advantage over Salt River Valley. Now 

 the Deglet Noor date nearly matures at Tempe in the Salt River Valley and will surely ripen where 

 it will receive such a considerable sum of heat more than in the Salt River Valley. 



