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 (22). 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. 
Heluan. 
Mecca, Calif. 
Maxi- 
mum. 
Mini- 
mum. 
Maxi- 
mum. 
Mini- 
mum. 
Maxi- Mini- 
mum, mum. 
Tempe, Ariz. 
Maxi- 
mum. 
Mini- 
mum. 
January 71.0 
February 75.2 
March 83.5 
April 93.4 
May 101.7 
June 104.0 
July 104.0 1 
August 103.1 ! 
September 99. 1 ! 
October 93.0 I 
November S4. w 
December 74. 1 
Average for the 
year 90.5 ' 
Annual mean . . 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 
64.2 
67.6 
73.0 
S2.6 
90.7 
93.6 
95.5 
93.9 
89.6 
84.6 
75.7 
67.5 
81.5 
45.1 
46.8 
50.4 
59.0 
63.7 
67.3 
69.6 
70.2 
67.3 
64.4 
56.3 
48.4 
59.0 
70.2 
r 
66.3 
72.3 ! 
78.4 I 
85.7 J 
91.3 
101.8 
104.1 
104.8 
99.5 
S9.5 
36.9 
41.2 
48.9 
55.1 
60.3 
68.1 
75.8 
74.2 
67.1 
55. 5 
44.6 
36.5 
86.7 
71.0 
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 
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. 
