mingle with or interfere in any way with the main caravan. With the rear-guard the available extra porters and prisoners marched, whose duty it was to collect and bring in any loads or sick that had fallen out of the ranks. The caravan road itself merits some description. It is seldom more than ten inches wide, and wherever it goes the width never varies: whether crossing rocky uplands or traversing forests, descending mountains or the steep sides of ravines, it is always the same monotonous track.

It is wearying enough to follow for a few hours, but when the hours grow into days, and the days into weeks, one comes to regard it almost in the light of a personal enemy. After crossing a scorching sandy plain, with its dry blades of grass a foot or two apart — so drear and lonely that the insects do not even hum