res, thus sailing about, discovers with far-seeing eye the carrion
below, he immediately drops from his high orbit, and wings his way
downward. He is observed by that one circling nearest him; who, well
knowing the cause of the altered flight of his companion, at once
forsakes his own orbit and follows; and he, in his turn, is followed by
another; and so on to the end of the chain."

"But how can one of them tell that the other is gone in pursuit of
prey?" inquired Francois, interrupting Lucien in his explanation.

"Suppose you saw Basil at a great distance off on the prairie, could you
not tell by his actions when he had started game, and was in pursuit of
it?"

"Oh! yes! I could easily."

"Well, then, the vultures, who have far keener sight than you,
understand each other's movements thoroughly--even to the shaking of a
feather--so that they can easily tell when one of their number has a
good dinner in sight.

"I think I have shown," continued Lucien, "that they all start within a
few seconds of the same time; and as they fly in a nearly direct line
towards the object, if we knew the rate at which they go, it would only
remain for us to mark the date of their arrival, to be able to tell how
far they had come. Of course it is supposed that we have already noted
the time when the first one came upon the spot.

"If we suppose," continued Lucien, as he pointed up to the vultures,
"that the first of these has alighted here two hours ago, and we allow
them a flight of thirty miles an hour, we may then safely conclude that
some of those now coming in have made a journey of sixty miles this
morning. What think you of my theory?"

"It is, to say the least of it, a curious one, brother," replied Basil.

"But what are they waiting for now?" demanded Francois; "why don't they
at once fall to, and enjoy it while it is fresh?"

Francois' interrogatory was a very natural one. Most of the vultures,
instead of attacking the carrion, were, as we have already seen, sitting
perched upon rocks and trees--some of them in listless attitudes, as
though they were not hungry, and did not care to eat.

Basil proffered an explanation.

"No doubt," said he, "they are waiting until the flesh becomes putrid.
It is said that they prefer it in that state."

"And that," remarked Lucien, "is another assertion that has no
foundation in fact. They do _not_ prefer it in that state. On the
contrary, it is certain that vultures like the