his country was solely to make observations in natural history. On the
river Niger, in his road to the island Griel, he saw a great number of
pelicans, or wide throats. "They moved with great state like swans upon the
water, and are the largest bird next to the ostrich; the bill of the one I
killed was upwards of a foot and half long, and the bag fastened underneath
it held two and twenty pints of water. They swim in flocks, and form a
large circle, which they contract afterwards, driving the fish before them
with their legs: when they see the fish in sufficient number confined in
this space, they plunge their bill wide open into the water, and shut it
again with great quickness. They thus get fish into their throat-bag, which
they eat afterwards on shore at their leisure." P. 247.

XII. The knowledge and language of those birds, that frequently change
their climate with the seasons, is still more extensive: as they perform
these migrations in large societies, and are less subject to the power of
man, than the resident tribes of birds. They are said to follow a leader
during the day, who is occasionally changed, and to keep a continual cry
during the night to keep themselves together. It is probable that these
emigrations were at first undertaken as accident directed, by the more
adventurous of their species, and learned from one another like the
discoveries of mankind in navigation. The following circumstances strongly
support this opinion.

1. Nature has provided these animals, in the climates where they are
produced, with another resource: when the season becomes too cold for their
constitutions, or the food they were supported with ceases to be supplied,
I mean that of sleeping. Dormice, snakes, and bats, have not the means of
changing their country; the two former from the want of wings, and the
latter from his being not able to bear the light of the day. Hence these
animals are obliged to make use of this resource, and sleep during the
winter. And those swallows that have been hatched too late in the year to
acquire their full strength of pinion, or that have been maimed by accident
or disease, have been frequently found in the hollows of rocks on the sea
coasts, and even under water in this torpid state, from which they have
been revived by the warmth of a fire. This torpid state of swallows is
testified by innumerable evidences both of antient and modern names.
Aristotle speaking of the swallows says, "They pass