22 BULLETIN 1125, U. S. DEPARTMENT OF AGRICULTURE. 
ties is about simultaneous, in spite of the remoteness of the localities and 
marked difference in the temperature. At Dakhleh the mean temperature for 
the nine months of the growing period, from flowering to date harvest, February 
to October, inclusive, is 78.40° F. That of Heluan, the nearest record point to 
the Siwah date field, for the same period is 72.54° F., or 5.86 degrees lower. 
As shown in Table I, the summation of heat units from May to October, in- 
clusive, is 1.079 higher at Dakhleh than at Heluan. These figures, showing so 
many more available heat units for the Saidy than for the Siwah, would lead 
us to expect it to ripen earlier, provided the varieties are identical, and they 
offer the strongest argument presented in support of a varietal difference be- 
tween the two. 
The maximum yield of Siwah at Bedrashen is given as 100 kantars of 320 
pounds to the feddan, practically 1 acre, or often only 60 or 70 kantars. The 
maximum yield would then be 32,000 pounds to the feddan, which, allowing 
100 trees to the feddan, would give a yield of 320 pounds to the tree. At 80 
piasters per kantar the money return would be £80, or $400. Placing the yield 
at 60 kantars, the more probable average, the crop would be 19,200 pounds, or 
192 pounds to the tree. At the minimum price of 60 piasters per kantar the 
return would be £36 to the feddan, or $180 per acre; 70 kantars, a medium 
yield reported, would equal 22,400 pounds, or 224 pounds to the tree, a not 
unreasonable yield. This, at 80 piasters, would give £56, or $280 to the feddan 
or acre. This, it should be remembered, is on land valued at the rate of £100 
to £200 per feddan. 
T. W. Brown (6), whose valuable paper, published in 1916, is the 
most reliable and technical study of the date culture of Egypt yet 
made, considers the " Saidi " and " Siwi " as separate varieties, 
though admitting that they are " very closely allied." He says, " It 
has been suggested that the difference of the fruit of the two kinds 
is due to differences of climate. Is it not more probable that the 
Siwi has originated from seed of the Saidi ? " However, no constant 
differences in botanical characters can be found to support the idea 
that the " Sewi " of Gizeh is a seedling of the Saidy of the oasis. 
In the writer's judgment the migration by offshoots of Saidy from 
Siwa Oasis is the more probable explanation. Culturally and com- 
mercially there seems to be no discernible difference. The young 
Saidy trees from the importations of 1904 and 1905, now growing in 
the Cooperative Date Garden, at Tempe, Ariz., are in no way to be 
distinguished from the trees of " Oga de Bedrichen " imported in 
1901. The " Oga de Bedrichen " trees have been identified with the 
" Sewi " of Bedrachen and Hawamdieh. There can be no doubt, 
therefore, that the Saidy variety of the Libyan oases and the 
" Sewi " of Gizeh Province are one and the same. Any slight dif- 
ferences can be explained by difference in soil, water supply, and 
atmospheric temperature and humidity. Their positive identity un- 
der similar environment in Arizona and California seems to be no 
longer in question. The name " Sewi," indicating its origin in the 
Siwa Oasis, is no more than must be expected. With the bringing 
into the Nile Valley perhaps of caravan loads of Saidy dates from 
the oasis of Siwa for centuries past, what could be more natural than 
the desire to possess and cultivate this excellent and celebrated date 
in the Nile Valley? Merchant caravans made their headquarters 
at Kerdaseh and other villages along the desert border of the Nile 
bottoms opposite Cairo. Twelve days from Siwa in February, their 
favorite month for moving offshoots, would put a camel load of 
Saidy offshoots from Siwa into the rich bottom lands of Gizeh. 
In November, 1921, the writer visited the little Bedouin village of 
Abu Koash, a mile beyond the ruined pyramid of that name. It is 
built against the rocky base of Gebel Abu Roash, by some ancient 
