bout twenty or thirty
dollars for the same weight, where I understand it is chiefly converted
into a kind of glue. The difference between the two sorts has by some
been supposed to be owing to the mixture of the feathers of the birds
with the viscous substance of which the nests are formed; and this they
deduce from the experiment of steeping the black nests for a short time
in hot water, when they are said to become white to a certain degree.
Among the natives I have heard a few assert that they are the work of a
different species of bird. It was also suggested to me that the white
might probably be the recent nests of the season in which they were
taken, and the black such as had been used for several years
successively. This opinion appearing plausible, I was particular in my
inquiries as to that point, and learned what seems much to corroborate
it. When the natives prepare to take the nests they enter the cave with
torches, and, forming ladders of bamboos notched according to the usual
mode, they ascend and pull down the nests, which adhere in numbers
together, from the sides and top of the rock. I was informed that the
more regularly the cave is thus stripped the greater proportion of white
nests they are sure to find, and that on this experience they often make
a practice of beating down and destroying the old nests in larger
quantities than they trouble themselves to carry away, in order that they
may find white nests the next season in their room. The birds, I am
assured, are seen, during the building time, in large flocks upon the
beach, collecting in their beaks the foam thrown up by the surf, of which
there appears little doubt of their constructing their gelatinous nests,
after it has undergone, perhaps, some preparation from commixture with
their saliva or other secretion in the beak or the craw; and that this is
the received opinion of the natives appears from the bird being very
commonly named layang-buhi, the foam-swallow. Linnaeus however has
conjectured, and with much plausibility, that it is the animal substance
frequently found on the beach which fishermen call blubber or jellies,
and not the foam of the sea, that these birds collect; and it is proper
to mention that, in a Description of these Nests by M. Hooyman, printed
in Volume 3 of the Batavian Transactions, he is decidedly of opinion that
the substance of them has nothing to do with the sea-foam but is
elaborated from the food of the bird. Mr. Jo