SUMATRA. 
141 
The birds neO:, fo much celebrated asapecyliar delicacy of thetable, ®^rdi 
efpecially among the Chinefc, is foimd in different parts, but in the great- 
eft abundance about Croee, near the foiith end of the ifland. Four miles 
up the river of that name, is a large cave, where the birds, called Z^'- 
ens layo?*g, and which appear to be the common martin, build in vaft 
numbers. The nefts are diftinguiflied into white and black, of which 
the firft are by far the more fcarce and valuable,* being found in the 
proportion of one only to tw^enty five* 
The white fort fells in China, at the rate of a thoufand to fifteen hun- 
dred Spanifh dollars the pecul; the black is iifually difpofed of at Bata- 
via for about twenty dollars the fame weight, where I underfland it is 
chiefly converted into glue, of which it makes a very fuperior kind. The 
difference between the two, has by forae been fuppofed to be owing to 
the mixture of the feathers of the bird, with the vifcous fubflance, of 
which the nefts are formed ; and this they deduce from the experi- 
ment, of ftceping the black nefts for a ihort time in hot water, when they 
are faid to become, in a great degree, white. Among the natives I have 
heard a few affert^ that they are the work of a different fpecics of bird. 
It was fuggefted to me, that the white might probably be the recent 
nefts of the fcafon in which they were taken, and the black, fuch as had 
been ufed for a number of years fnccelEvely. This opinion appearing 
plaufible, I was parcicular in my enquiries as to that point, and learned 
what fecmed niuch to corroborate it, M^hen the natives prepare to take 
the nefts, they enter the caves with torches, and forming ladders accord- 
ing to the ufual mode, of a fingle bamboo notched, they afcend and pull 
down the nefts, which adhere in numbers together, from the fide and 
top of the rock, Tliey informed me, that the more frequently and re- 
gularly the cave is ftript, the greater proportion of white nefts they are 
fure to find, and that on this experience they often make a pratftlce of 
beating down and deftroying the old nefts, in larger quantities than they 
♦ I ha4 an opporhiity of giving to the Britlfh Mufeum, forac of ihefe white neftj, with f^^^s 
in them* Thofe found in the Saltpetre caves btfore mentioned, arc probably of the fame fpecies 
of hUd, 
trouble 
