The boys made fair progress, taking advantage of clumps of bushes, trunks of trees, and fallen timber.
"Slower," whispered Bob in his brother's ear. "They are getting uneasy. Notice how often that old bull throws up his head and sniffs the air? He trots away, only to come back again to his family. Now, again forward. This log will give us a good boost, I think."
"We don't want the old bull," Sandy managed to say in the other's ear.
"Hardly. He'd be too tough eating. You take the half-grown calf, and leave the cow to me," said the older hunter; and then made a gesture that prohibited further communications.
Presently Bob realized that they had crept as close as seemed necessary.
He caught the eye of Sandy, and nodded his head. Knowing what the programme was to be, for they had gone through it many times together, the other gradually managed to raise himself to a position where he had one knee on the ground. This was an ideal position for shooting, as it gave him a chance to rest his elbow on the other knee, to steady himself at the final instant.
To Bob it was given to pick the time of firing. He had to watch closely, in order to make sure that both animals selected were free from trees, so that they might not uselessly waste precious ammunition.
"Shoot!" he said, quickly.
Bang! roared his own heavily-charged musket. The cow went floundering down, and never again arose, for Bob's aim had been true.
Sandy was not quite so fortunate. Just at the second when Bob gave the word to fire, the half-grown young buffalo chanced to step behind a large tree trunk, so that it was out of the question to dispose of him while standing still.