Cameron measured the water in his canteen by its weight. Evaporation
by heat consumed as much as he drank. During one of the rests, when
he had wetted his parched mouth and throat, he found opportunity to pour
a little water from his canteen into Warren's.

At first Cameron had curbed his restless activity to accommodate
the pace of his elder comrade. But now he felt that he was losing
something of his instinctive and passionate zeal to get out of
the desert. The thought of water came to occupy his mind. He
began to imagine that his last little store of water did not
appreciably diminish. He knew he was not quite right in his mind
regarding water; nevertheless, he felt this to be more of fact
than fancy, and he began to ponder.

When next they rested he pretended to be in a kind of stupor; but
he covertly watched Warren. The man appeared far gone, yet he had
cunning. He cautiously took up Cameron's canteen and poured water
into it from his own.

This troubled Cameron. The old irritation at not being able to
thwart Warren returned to him. Cameron reflected, and concluded
that he had been unwise not to expect this very thing. Then, as
his comrade dropped into weary rest, he lifted both canteens. If
there were any water in Warren's, it was only very little. Both
men had been enduring the terrible desert thirst, concealing it,
each giving his water to the other, and the sacrifice had been useless.

Instead of ministering to the parched throats of one or both, the
water had evaporated. When Cameron made sure of this, he took one
more drink, the last, and poured the little water left into Warren's