trict than the
other species--a proof that gnats and other insects do also abound to a
considerable height in the air; they also range to vast distances, since
locomotion is no labour to them who are endowed with such wonderful
powers of wing. Their powers seem to be in proportion to their levers,
and their wings are longer in proportion than those of almost any other
bird. When they mute, or ease themselves in flight, they raise their
wings, and make them meet over their backs.

At some certain times in the summer I had remarked that swifts were
hawking very low for hours together over pools and streams, and could not
help inquiring into the object of their pursuit that induced them to
descend so much below their usual range. After some trouble, I found
that they were taking _phryganeae_, _ephemerae_, and _libellulae_ (cadew-
flies, may-flies, and dragon-flies), that were just emerged out of their
aurelia state. I then no longer wondered that they should be so willing
to stoop for a prey that afforded them such plentiful and succulent
nourishment.

They bring out their young about the middle or latter end of July: but as
these never become perchers, nor, that ever I could discern, are fed on
the wing by their dams, the coming forth of the young is not so notorious
as in the other species.

On the 30th of last June I untiled the eaves of a house where many pairs
build, and found in each nest only two squab, naked _pulli_; on the 8th
July I repeated the same inquiry, and found that they had made very
little progress towards a fledged state, but were still naked and
helpless. From whence we may conclude that birds whose way of life keeps
them perpetually on the wing would not be able to quit their nest till
the end of the month. Swallows and martins, that have numerous families,
are continually feeding them every two or three minutes, while swifts,
that have but two young to maintain, are much at their leisure, and do
not attend on their nest for hours together.

Sometimes they pursue and strike at hawks that come in their way, but not
with that vehemence and fury that swallows express on the same occasion.
They are out all day long in wet days, feeding about, and disregarding
still rain: from whence two things may he gathered; first, that many
insects abide high in the air, even in rain; and next, that the feathers
of these birds must be well preened to resist so much wet. Windy, and
particularly windy weather