of
grey limestone or white marble. The colour and value of the nests depend
on the quantity and quality of the insects caught, and perhaps also on
the situation where they are built. Their value is chiefly ascertained
by the uniform fineness and delicacy of their texture; those that are
white and transparent being most esteemed, and fetching often in China
their weight in silver.

"These nests are a considerable object of traffic among the Javanese,
many of whom are employed in it from their infancy. The birds, after
having spent nearly two months in preparing their nests, lay each two
eggs, which are hatched in about fifteen days. When the young birds
become fledged, it is thought the proper time to seize upon their nests,
which is done regularly three times a year, and is effected by means of
ladders of bamboo and reeds, by which the people descend into the
caverns; but when these are very deep, rope-ladders are preferred. This
operation is attended with much danger, and several perish in the
attempt. The inhabitants of the mountains generally employed in this
business begin always by sacrificing a buffalo, which custom is observed
by the Javanese on the eve of every extraordinary enterprise. They also
pronounce some prayers, anoint themselves with sweet-scented oil, and
smoke the entrance of the cavern with gumbenjamin. Near some of the
caverns a tutelar goddess is worshipped, whose priest burns incense, and
lays his projecting hands on every person preparing to descend. A
flambeau is carefully prepared at the same time, with a gum which exudes
from a tree growing in the vicinity, and which is not easily
extinguished by fixed air or subterraneous vapours."

"But how are the nests eaten, Uncle Thomas? Are they prepared in any
way, or are they fit for use as they are taken down?"

"They are always prepared before they are eaten. The finest sort, which
are of a clear colour, and not unlike isinglass, are dissolved in broth,
to which they are said to give an exquisite flavour. After being soaked,
they are sometimes introduced into the body of a fowl and stewed; but I
am not quite versed in all the mysteries of a Chinese kitchen, so you
must be satisfied with these two modes of preparation."

"Thank you, Uncle Thomas."

"I have only one more story to tell you about the swallow, Boys, and
then I must turn to two or three other animals, whose peregrinations
exhibit as strong instances of instinct as it does."

"A sw