258 
THE TIGRIS 
* 
carry off the superflux of waters, when the spring inundations 
from the Euphrates would pour them too abundantly towards 
the Tigris shore. One of these old canals, in better condition 
than the rest, by its sudden filling gives the first signal to Bag¬ 
dad, of the overflowing of the great river. The direction of this 
canal is north-west, and it communicates with the ancient divi¬ 
sion of the city, a little to the southward of the Hillah gate. 
The Tigris varies as much in the rapidity, as in the depth of 
its stream, both being governed by the periodical waters that 
rush from the mountains of Armenia, where its sources are, 
about fifty miles north-west of the valley of Diarbeker. It flows 
thence, with a swiftness that gave it the ancient Persian name of 
Teer or Tir , the arrow, which is descriptive of its course. The 
average rate of its current is about seven knots an hour. Its 
first swell takes place in April, and is produced by the melting 
of the winter snows in the mountains ; its second appears to¬ 
wards the close of October, or the beginning of November, and 
rises immediately after the annual rains in those high regions. 
But it is only during the spring torrents, that a complete inun¬ 
dation covers the land, and the city of Bagdad stands like a 
castellated island in the midst of a boundless sea. This mighty 
flood does not, however, owe all its waters to the Tigris ; those 
of the vaster Euphrates, which flow also from Armenia, having 
received their superabundance about the beginning of March, 
continue increasing in elevation till the end of April; at which 
period, the river being at its highest pitch, remains so until the 
expiration of June ; and, during that time, having spread its 
welcome waters to meet the overflowing Tigris, both, united 
cover the surrounding country, west, east, and south, to beyond 
the reach of sight. Soon after they have subsided, spots, which 
