veller in the
desert. After that the General often sent for the Sheikh Moussa to ride
with him on the march; and he questioned him, and compared his answers
with the maps and plans he had. And the more he was tested the more
genuine did the man appear. The tribe, too, to which he claimed to
belong was known to be friendly, and not as yet overawed into owning
allegiance to the Mahdi.

And so the square dragged slowly on from well to well through the long
scorching mornings and the bright moonlight nights, and was swallowed up
in the desert.

CHAPTER TEN.

SENT OUT SCOUTING.

It is one of the first principles of warfare that an army should always
keep up communication with what is called its _base_, that is, the safe
place from which food, ammunition, stores of all kinds, and fresh men to
supply the place of those who fall, can be sent to it, and to which the
sick and wounded may be returned. But as there is no universal rule in
anything, and people have often to do what they can, rather than what
they know to be best, it so happens that columns have sometimes to be
launched into an enemy's country without any communication with seaport,
town, or friendly frontier, so that they are entirely self-dependent,
with no resources beyond what they have at hand, and liable to be
attacked on all sides.

This is termed being "in the air," and is a very great risk, which is
only voluntarily incurred for the sake of gaining some equally great
advantage. In civilised warfare failure under such circumstances means
surrender; in expeditions against barbarians it involves utter
destruction.

Hicks Pasha's little army was now thus isolated, and, after several
days' march across the desert, matters began to wear a very serious
aspect. As has been said, ten miles a day were the utmost that could be
accomplished, and the distance between the places where water could be
obtained increased as they advanced.

Water was carried by camels in tanks with galvanised linings, which kept
it fresh, and free from the nauseous taste which it gets from the skins
in which travellers generally have to keep it. It is true that there is
an earthenware water-bottle, which is in much request, and the
inhabitants of a town on the Nile earn their livelihood by manufacturing
them. But the porousness of the clay, which keeps the contents so
deliciously cool, makes them very brittle.

In these tanks sufficient water could be carried for twenty