nt kinds. The sand-martin is the
smallest of the family; as the birds fly by us you notice that the
back part is brown, or mouse colour; the under part white. The back of
the house-martin is of a glossy black or bluish-black colour; it is
white underneath; while the swallow, which is larger than the other
two, has a glossy back, like the house-martin; but underneath it is
more or less tinged with buff; and see, as I speak here is one flying
past us. To-day is the 12th of April, about the time the swallow
generally comes to this country. Now you see clearly enough its
colour, and you will notice, too, a very marked difference in the form
of its tail; see how much forked it is, much more so than the tail of
the martin. This forked appearance is produced by the two outer tail
feathers, which are much longer than the rest. Now I hope you will
take notice of these differences, and call things by their right
names, instead of jumbling them all up together under the name of
swallow. I have not spoken of the swift, which does not visit this
country till May; it is the largest of the swallow family, and has the
whole of its body, both above and beneath, of a blackish-brown colour,
except a small patch of dirty white under the chin.

"But, papa," said Jack, "do all these four kinds of swallows come from
Africa? It is very curious to know how they can find their way
backwards and forwards from Africa to this country, and how they come
back to the very spots they visited the year before?" Indeed, it is a
very curious thing; nevertheless experiments have been made to show
that these birds return every year to the same localities.

Many years ago Dr. Jenner procured several swifts from a farmhouse in
Gloucestershire, and marked them by cutting off two claws from the
foot of twelve of them. Next year their hiding places were examined in
the evening, when the birds had gone to roost, when Dr. Jenner found
many of the birds he had marked by cutting off the two claws. For two
or three consecutive years he examined their nesting places, and
always found some of his marked birds. At the end of seven years a cat
brought a swift into the farmer's kitchen, and this was one of those
which Dr. Jenner had marked. Now, Willy, I will ask you a question in
geography. The swallow family visits this country from Africa. What
sea, then, must the birds fly across? "The Mediterranean, papa." Quite
right; and now can you tell me the narrowest part of th