DATES OF EGYPT AND THE SUDAN. 9 



for a few exceptionally early sorts. 1 This apparent discrepancy may 

 be explained for United States localities by the frost interference in 

 the spring and fall, while the Nile delta region is practically frostless; 

 the coast entirely so, while the Gizeh district is subject to rare and 

 only light frosts. With frost immunity in autumn, the dates of the 

 Egyptian maritime belt may hang on the trees, slowly maturing, even 

 after the mean temperature falls below 64.4° F., as it does by the first 

 to the middle of November. It must be remembered, too, that these 

 dates do not mature upon the trees, but are cut and marketed in what 

 is called a "hard ripe" condition, the sugar deposits being probably 

 completed, but with the enzymic actions which promote the ripening 

 not yet begun. 



This region, having a mean temperature of 70° F. from February 

 to October, inclusive, does not produce packing dates at all. The 

 Amri, the one important packing date of the delta, is produced at Sali- 

 hieh, Korain, Fakus, and a few at Birket el Hadji, all points in the 

 margin of the delta lands bordering on areas of bare desert sands. 

 (PL III, fig. 1 .) Manshia, on the margin of the delta, a few miles north 

 of the Gizeh Pyramids, where considerable quantities of both Amhat 

 and Siwah dates are cured, has a climate so influenced by the proximity 

 of the Libyan Desert that it should be considered under the same cate- 

 gory. The record of Abbasia, the suburb of Cairo on the rocky slopes 

 of the naked hills to the northeast of the city, may be taken as most 

 nearly representative of these border localities, especially of Birket el 

 Hadji and Manshia. Here (Table I) the mean for the year is but a 

 fraction below 70°, that for the growing months of February to Octo- 

 ber being 73.68°; and the summation of heat units from May to Octo- 

 ber is 2,714. An incomplete record for Ismailia, 2 on the Suez Canal 

 about 25 and 30 miles southeast of Salihieh and Korain, agrees within 

 an average of 1° in the monthly means with the records of Abbasia 

 and gives an almost identical summation of heat units above 64.4°. 

 The mean relative humidity is between that of Abbasia and that of 

 Heluan, but with less fluctuation than either. 



Even with the additional heat afforded by these localities on the 

 desert border, the dates are pulled from the stems in an immature 

 "hard ripe" condition, and the ripening is completed in drying yards, 

 preferably on floors of coarse pebbles to reflect the heat. 



It is from such higher temperature conditions at Birket cl Hadji, 

 where their groves border the s;m<l hills toward the open Arabian 



> Thoma If. Kearney, on pages 20 and 21 <>r Bulletin !i2of the Bureau of Vlant Industry, entitled "Date 

 Varieties and Date Culture in Tunis," show.s that at Susa on the Mediterranean coast, 120 miles north of 



. ,'arietie; of dale-: are frown where llio summation Of beat Units is probably less than that of 

 Hfar (1,908* F.). 'I he e are, however, varied".- of interior quality and the fruit keeps but a short time 



after gathering, 

 2 Lyons, if. <>.. Phy lography of the Nile River and 11 1 Basin, 111 i>., is pi, Cairo, 1908. 

 w,\; IJull. 271 L5 —2 



