27 



Instead of taking the bed of the river as the zero of the scale, it is 

 referred to mean sea level at Alexandria/' It is impossible, therefore, 

 to tell the depth of the water b}' reading- the scale. The gage on the 

 south end of Elephantine Island is of the same character as those on 

 the island of Philae. The modern gage is carefully constructed, being 

 inscril)ed on pieces of white marble. The gages at Philae are the 

 most reliable, as the channel of the river there is composed of granite, 

 and from the records of a great many .vears it is found that the aver- 

 age heights of the river have varied l:)ut little. The gages on the 

 Lower Nile are of little value in comparison, as the bed of the river 

 is constanth" changing. 



B}" far the most celebrated of the gages on the Lower Nile is the 

 one on the island of Rhoda. The graduations are -on a pillar which 

 stands in the center of a well, the bottom of which is connected with 

 the Nile by a passage. This column is of stone, octagonal in cross 

 section, and the well in which it stands is about 10 feet square. The 

 nilometer is graduated in pics and kirats. 



At the present time the irrigation engineers depend for their hrst 

 news regarding the stage of the Nile on telegraphic reports from 

 Khartum. The people, however, look to Assuan for their informa- 

 tion and are scarcely satisfied until reports are received from that 

 place. From apjjroximate gagings . made of the Nile at Assuan the 

 writer has prepared a rating table, from which the yearly discharges 

 of the river have been computed, as shown in ligs. 2 and 3. These 

 diagrams are trustworthy only in so far as the gagings are assumed 

 to be correct. 



The English engineers have established gauges at a number of points 

 along the Nile above Assuan, among which are those at Khartum, Ber- 

 ber, Wad}' Haifa, and Lake Victoria. From the reports received from 

 these gaging stations the engineers know approximately what kind of 

 a flood to expect each year, and the irrigator is advised according!}". 



AGRICULTURAL SEASONS. 



There are three agricultural seasons in Eg3^pt. The land not receiv- 

 ing perrennial irrigation can take advantage of but one. This ])egins 

 as early as the middle of October and ends with March. The crops 

 grown then under the basin sj'stem are sown iunnediately after the 

 su])sidence of the flood, hence the time of planting depends upon when 

 the fields become dry enough for the seed (PI. IV). The lands in 

 southern Egypt are generally ready for the seed about the beginning 

 of November. In the Delta crops are often planted as late as the 20th 

 of December. Wheat is the principal'winter crop, although clover, 



« In the same manner the height of a dam or other structure is usually given by- 

 referring to the actual elevation of its base and top above sea level. 



