_fourth_, or lowest kind, is
called _aia_ of Cambaia, being sold into that country[148]. Thus sorted,
and prices affixed to each, there are merchants from all countries ready
with their money, so that in a few days all the pearls are bought up,
according to their goodness and weight.

[Footnote 148: Pearls are weighed by _carats_, each of which is four
grains. The men who sort and price them have a copper instrument with
holes of various sizes, by which they estimate their several
values.--_Hakluyt_.]

In this sea of the pearl-fishery there is an island called _Manaar_,
over-against Ceylon, inhabited by Christians who were formerly Gentiles,
and in which island there is a small fort belonging to the Portuguese.
Between this island and Ceylon there is a narrow channel with a small
depth of water, through which only small ships can pass at the full and
change of the moon, when the tides are high, and even then they must put
their cargoes into lighters to enable them to pass the shoals, after
which they take in their goods again, and proceed on their voyage. But
large ships going for the eastern coast of India pass by the coast of
Coromandel, on the other side of this gulf, beside the land of
_Chilao_[149], which is between the firm land and the isle of Manaar. On
this voyage ships are sometimes lost, but they are empty, as ships going
this way discharge their cargoes at _Periapatam_ into small
flat-bottomed boats named _Tane_, which can run over any shoal without
danger, as they always wait at Periapatam for fine weather. On departing
from Periapatam, the small ships and flat-bottomed boats go always
together, and on arriving at the shoals about thirty-six miles from that
place, they are forced through by the winds, which always blow so
forcibly that they have no means of taking shelter during the passage.
The flat boats go through safely; but if the small ships happen to miss
the proper channel, they get fast on the shoals, by which many of them
are lost. In coming back from the Indies, instead of this passage, they
take the channel of Manaar, which has an ouze bottom, so that even in
case of grounding they are generally got off again without damage. The
reason of not using this passage on the outward voyage is, that the
prevailing winds between Ceylon and Manaar frequently occasion that
channel to have so little water that it cannot be navigated. From Cape
Comorin to the island of Ceylon, the distance is 120 miles.