281 
from the Nile to the Red Sea. 
of the inundation, is 9 feet above the high-water, and 14 above 
the low- water level at Suez ; and, farther, that the mean height 
of the river corresponds very accurately with that of the tide. 
The actual height of the high and the low Nile at Bubastis, 
where the ancient canal commenced, seems not to have been ob- 
served ; but assuming that the surface of the river declines uni- 
formly, the height of the low Nile there has been estimated by 
the French engineers at 10 feet ; the increase during the inun- 
dation at 18 feet; and the extreme height, of course, at 28 feet, 
above the Mediterranean. 
As the modern artifice of locks was unknown to the ancients, 
their canals were necessarily upon one level, and could communi- 
cate with the sea only when the tide had the same, or nearly the 
same, elevation as the water in the canal. Besides, to carry the 
water of the Nile to Suez (90 miles) in sufficient quantity, to sup- 
ply the waste occasioned by evaporation and infiltration, a fall 
of one or two feet would be requisite. Now, the greatest height 
of the'Nile at Bubastis, being 28 feet above the Mediterranean, 
or S feet above low tide at Suez, a canal carried from the one 
place to the other, though filled at the extreme rise of the inun- 
dation, would scarcely have a greater height than was necessary 
to keep it on a level with the low tide in the Red Sea. But the 
Nile retains this extreme height at Bubastis, only for a few 
weeks ; and hence the probability is, that the passage from sea 
to sea, by the Nile, could only be open for a corresponding pe- 
riod. The French engineers think, that, when the Pelusiac 
branch of the Nile was open, the water might stand 2 or S feet 
higher at Bubastis than at present, and that the canal might 
then afford, at the utmost, two months’ navigation. The known 
tendency of rivers, in alluvial districts, to raise their beds, ra- 
ther warrant an opposite opinion ; but the subject would not re- 
pay the labour of discussion. On any hypothesis, it is evident 
that the transit from the river to the Red Sea, must have been 
limited to a very short period of the year. The canal, however, 
if cut deep, might continue navigable for boats four or five 
months instead of one ; but these boats being unable to enter 
the Gulf, must have had their cargoes transhipped at Arsinoe. 
Hence the canal must have been used almost solely for internal 
traffic, and that only for four or five months in the year. The 
