NITRIA BAHAR BELA MA. 
129 
The season of collecting this substance is in the 
month of August, in the interval between seed- 
time and harvest. The natron trade was former- 
ly engrossed by the inhabitants of the canton of 
Terane, who annually collected about twenty-five 
thousand quintals, the greater part of which was 
exported to Venice, France, and England. 
The use of natron ascends to a very high anti- 
quity. Pliny, who prefers the Macedonian to the 
Egyptian, on account of its superior purity and 
clearness of colour, celebrates its numerous medi- 
cal virtues, and relates, that, when liquified with 
sulphur, it was formed into vases. Near one of 
the lakes, the vestiges of a manufactory of glass 
may still be traced, by the fragments of scoria, 
and the ruins of its furnaces. Perhaps a more 
favourable situation could not have been selected 
for procuring the two materials of glass, soda and 
vitrifiable sand. 
To the west of Nitria, and extending in the 
same direction, lies the valley of the river with- 
out water, denominated by the Arabs, Bahar Be- 
la Ma, which is conjectured to have formed the 
communication between the lakes Moeris and Ma^ 
reotis, and is separated from the valley of Nitria 
by a ridge of calcareous stone, covered with sand. 
As this valley forms the western barrier of Egypt, 
all vegetation is choked, and the soil is encumber- 
ed with banks of the sand which it intercepts a§ 
VOL. IT. I 
