The quantity of edible birds'-nests alone, annually exported from Java to China on vessels of this description, is estimated at not less than two hundred _píkuls_, of which by far the largest proportion is the produce of the Javan rocks and hills. It is well known that these are the nests of a species of swallow (hirundo esculenta) common in the Malayan islands, and in great demand for the China table. Their value as a luxury, in that empire, has been estimated on importation to be weight for weight equal with silver. The price which these nests of the best quality have of late years brought in the Canton and Amoi market, has been forty Spanish dollars per _káti_, of rather more than a pound and a quarter English. They are usually classed into first, second, and third sorts, differing in price from forty to fifteen Spanish dollars, and even to ten and less for the most ordinary. The price in the Batavian market rises as the period for the departure of the junks approaches; but as the principal produce of Java is still a monopoly in the hands of government, it is difficult to fix the price at which they might be sold under other circumstances. Generally speaking, however, they sell throughout the Eastern Islands considerably lower than they are calculated to do in China, which may be accounted for by the perishable nature of the commodity, and the great care necessary to preserve them from the damp, as well as from breakage. On this account, they are seldom bought by European traders. Birds'-nests consigned by the Javan government to the Canton factory in 1813, sold to the amount of about fifty _píkuls_, at an average rate of about twenty dollars per _kati_: but this was at a period when the China markets were unusually low. The quantity of birds' nests obtained from the rocks called _Kárang bólang_, on the southern coast of Java, and within the provinces of the native princes, is estimated, one year with another, at a hundred _píkuls_, and is calculated to afford an annual revenue to the government of two hundred thousand Spanish dollars. The quantity gathered besides by individuals, on rocks and hills belonging to them, either in private property or held by farm from the government, in other parts of the island, may amount to fifty _píkuls_; making the extent of this export not less than one hundred and fifty _píkuls_, besides the amount of the collections from the other islands of the Archipelago.