SAIDY DATE OF EGYPT. 



29 



mean temperature curves of Mecca and Tempe on the diagram of 

 means of 12 Egyptian and Sudan stations (Fig. 4), heretofore pub- 

 lished (£2). The difference in the form of these two American 

 curves, as compared with those of Egypt, must at once call atten- 

 tion to the different type of climate into which this date has been 

 transplanted in America. The American curves are higher and 

 narrower toward the apex than any of the Egyptian — that is, the 

 range of monthly means for Mecca is greater than for Dakhla or 

 for any Egyptian station except Aswan, but the extreme summer 

 temperatures are not so long sustained. For the first two months 

 of the year the American stations have the temperatures of the 

 cooler stations of Egypt, but pushing relatively higher and passing 

 all the Lower Egypt stations as the season advances, though escap- 

 ing the extreme heat of the " Desert tropical " {22) stations and of 

 Dakhla from March to June. Through July and August alone 

 Mecca is hotter than Dakhla, and Tempe is equal to it. But the 

 Mecca curve drops below all the upper Nile stations in September 

 to the level of Dakhla and falls below all Egyptian and Sudan 

 stations from October to the end of the year. 



Table 1. — Monthly mean, maximum, and minimum temperatures, in degrees F., 

 of Dakhla Oasis and Heluan, in Egypt, and of Mecca, Calif., and Tempe, 

 Ariz. 



Month. 



Dakhla Oasis. 



January 



February 



March 



April 



May 



June 



July 



August 



September 



October 



November 



December 



Average for the 

 year 



Annual mean.. 



Maxi- 

 mum. 



71.0 



75.2 



83.5 



93.4 



101.7 



104.0 



104.0 



103.1 



99.1 



93.0 



84.0 



74.1 



90.5 



Mini- 

 mum. 



74.9 



42.3 

 43.9 

 50.0 

 60 6 

 66.2 

 72.1 

 73.4 

 73.0 

 69.8 

 62 6 

 54.7 

 44.6 



59.4 



Heluan. 



Maxi- 

 mum. 



64.2 

 67.6 

 73.0 

 82.6 

 90.7 

 93.6 

 95.5 

 93.9 

 89.6 

 84.6 

 75.7 

 67.5 



81.5 



Mini- 

 mum. 



45.1 

 46.8 

 50.4 

 59.0 

 63.7 

 67.3 

 69.6 

 70.2 

 67.3 

 64.4 

 56.3 



59.0 



70.2 



Mecca, Calif. 



Maxi- 

 mum. 



Mini- 

 mum. 



66.3 

 72.3 



78.4 

 85.7 

 91.3 

 101.8 

 104.1 

 104.8 

 99.5 

 89.5 

 78.6 

 68.3 



36.9 

 41.2 

 48.9 

 55.1 

 60.3 

 68.1 

 75.8 

 74.2 

 67.1 

 55.5 

 44.6 

 36.5 



55.4 



71.0 



Tempe, Ariz. 



Maxi- 

 mum. 



67.5 

 70.3 

 76.9 

 84.5 

 93.0 

 103.1 

 104.2 

 102.3 

 99.6 

 87.1 

 75.4 

 64.8 



85.7 



Mini- 

 mum. 



68.2 



35.3 

 37.9 

 43.5 

 48.1 

 52.4 

 60.5 

 72.2 

 72.7 

 63.3 

 50.2 

 39.5 

 34.1 



50.8 



Saidy palms at Mecca must make up in the extra heat of July 

 and August for the heat units in which Dakhla has been ahead 

 from March to June. That they actually do this is proved by the 

 fact that the Saidy trees at Mecca ripen their fruit a little earlier, 

 if anything, than those at Dakhla. 



The Tempe mean curve has the same form as that for Mecca 

 and is nearly parallel with it, but after January it is about 3° F. 

 lower throughout the year. From the relation of this curve to 

 that of Heluan we should expect the Saidy to ripen at Tempe, 

 for it shows Tempe to be the warmer station by from 3° to 6° F. 

 through June, July, August, and September. It is only the analysis 

 of the maximum and minimum temperatures of these stations that 

 shows where Tempe fails. 



