In the vicinity of the rocks are usually found a few persons accustomed from their infancy to descend into these caverns, in order to gather the nests; an office of the greatest risk and danger, the best nests being sometimes many hundred feet within the damp and slippery opening of the rock. The gatherers are sometimes obliged to lower themselves by ropes (as at _Kárang bólang_) over immense chasms, in which the surf of a turbulent sea dashes with the greatest violence, threatening instant destruction in the event of a false step or an insecure hold. The people employed by government for this purpose were formerly slaves, in the domestic service of the minister or resident at the native court. To them the distribution of a few dollars, and the preparation of a buffalo feast after each gathering, was thought sufficient pay, and the sum thus expended constituted all the disbursements attending the gathering and packing, which is conducted by the same persons. This last operation is however carefully superintended by the resident, as the slightest neglect would essentially deteriorate the value of the commodity[60]. Although the Malayan camphor, which is the exclusive produce of Sumatra and Borneo, is much stronger than the camphor from China, it has not yet been considered an article of extensive export for the European market. It is always, however, in the greatest demand in China, where it is either consumed, or as has been supposed by some, it undergoes a certain process previous to its re-exportation under a different appearance. It is not known in what manner the China camphor for the European market is prepared; and unless the Malayan camphor is used in the composition, it seems difficult to account for the constant demand for it in China, whence it is never re-exported in its original state. Whatever value may be set on the Chinese camphor, that exported from Japan is of a still superior quality, and more in demand for the European market. _Bich de mar_ is well known to be a dried sea slug used in the dishes of the Chinese: it is known among the Malayan Islands by the name of _trípang_, and collected on the shores of nearly all the islands of the Archipelago. It usually sells in China at from ten to fifty dollars per _píkul_, according to its quality, but being an article still more perishable than the birds'-nests, and very bulky and offensive, it seldom composes the cargoes of European vessels. It would be very difficult to ascertain the average price, as it varies according to the difficulties experienced in collecting it, and the immediate demand in the market, for its perishable nature will not admit of the excess of one season being laid by to meet the deficiency of another. It requires constant care on the voyage, and a leaky vessel frequently loses a whole cargo.