A sentry's challenge rang out sharply.
One glance at their papers, and he waved them on.
Up and down hill they tramped. The day was superb, and legions of light, fleecy clouds sent legions of delicate shadows skimming across the landscape. But though peace was in nature the ambulanciers were always forcibly reminded of the fact that the great war was going on all about them.
Over the brow of another ridge a sign conspicuously nailed to a tree brought them to a pause.
"No vehicles further than this by daylight," they read.
"I am a sufficient believer in signs to pay attention to that warning," remarked Chase, with an uneasy look on his face.
"It certainly wouldn't be wise to venture where vehicles may not go," laughed Don.
"Scarcely!" put in Dunstan, dryly.
Retracing their steps, the three soon reached a rather narrow crossroad running in an easterly and westerly direction over a series of hills. After following the much-traveled thoroughfare for a considerable distance, the boys discovering, by the aid of Dunstan's map, that they were being taken out of their way, decided to leave it. The ascent up a steep slope, plentifully bestrewn with vegetation, was so hard and toilsome that all were delighted, on arriving at the top, to discover a broad, almost level field stretching over to a tree-crowned ridge about two hundred and fifty yards away.
"Thank goodness!" panted Chase.