.182 
THE NATIONAL GEOGRAPHIC MAGAZINE 
rope to accommodate the diver's foot. 
The stone is suspended at a depth of 4 to 
5 feet below the surface by means of a 
cord attached to an outrigger. 
When ready to descend, the diver 
places one foot on the stone, the other on 
the rim of a rope basket attached to a 
rope, inflates his lungs, loosens the slip- 
knot holding the stone, and sinks rapidly 
CO the bottom. There he at once disen- 
gages his foot and quickly crawls over 
the bottom, tearing loose all the oysters 
he can reach and putting them in the 
basket. When near the limit of his en- 
durance, he gives a signal with the bas- 
ket rope and is quickly hauled up by the 
watchful attendant, or "manduck," with 
whom the diver is provided. The helper 
has meanwhile pulled up and secured the 
diving stone, and when the basket is 
hauled in he culls the catch from the mis- 
cellaneous refuse that is attached to the 
oysters. 
HOW LONG CAN A DIVE;r RE^MAIN UNDER 
WATER ? 
The divers usually operate in pairs, 
with a common attendant and diving 
stonCo The descents occur at intervals of 
5 or 6 minutes. The best divers are care- 
ful to dry their bodies thoroughly after 
each descent and to take sufficient rest. 
Between dives they often smoke a pipe 
or cigarette, sometimes while in the 
water just preparatory to a dive. 
The divers have learned by experience 
that they may increase the length of 
their submergence by making 9 1 .mber 
of deep, forced respiratory effort; before 
taking the plunge. Most exaggerated 
stories have been told and are still cur- 
rent regarding the length of time the 
divers can remain under water. 
The Arab divers wear nose-clasps of 
flexible horn attached to a cord around 
their neck, while the divers of other races 
simply compress their nostrils by hand 
during the descent. This practice can 
hardly make any difference in efficiency, 
and we must conclude that the expert- 
ness of the Arabs depends on an aptitude 
born of long experience. 
Their usual time below the surface is 
60 to 75 seconds, the normal maximum 
not exceeding 90 seconds, while the 
Tamil and Moormen divers range from 
35 to 50 or 60 seconds, depending on the 
depth. There is a well authenticated case 
in 1887 of an Arab who remained undo: 
for 109 seconds in water 7 fathoms deep 
The most curious feature of many ot 
the ancient and some of the modern ac- 
counts of the pearl fishery is the remark- 
able ability to remain under water as- 
cribed to the Arabs and others, and it h 
noteworthy that this ability increases 
with the remoteness of the time. Per- 
cival, whose "Account of the Island of 
Ceylon" was published in London in 
1803, said the usual time for the divers 
to remain submerged "does not much 
exceed two minutes, yet there are in= 
stances known of divers who could re- 
main four or even five minutes. , . . 
The longest instance ever known was of 
a diver who came from Anjango in 1797. 
and who absolutely remained under 
water full six minutes." 
Le Beck, in his "Asiatic Researches," 
London, 1798, reports that he saw a 
diver remain down for seven minutes. 
Sir Phiiiberto Vernatti reported to the 
Royal Society of London in 1667, in re- 
sponse to a special inquiry of the society, 
that "the greatest length of time that 
pearl-divers in these parts [Ceylon] can 
continue under water is about a quarter 
of an hour." 
The Dutch anatomist Diemerbroeck. 
in his '^AnsLomy of the Human Body" 
(1672), cites the case of a diver who, 
under ^.is own observation, used to work 
und€ water for half an hour at a time : 
and Batuta, another .ris ^ of science, 
writing of pearl-divers in 1336, said that 
"some remain down an hour, others two 
hours, others less." 
The number of oysters taken at each 
dive necessarily varies greatly, depend- 
ing on the diver, the depth, and the den- 
sity of the growth. On what is regarded 
as good ground, the average per man 
per dive is 25 to 35 ; but it sometimes 
rises to 75 or drops to 5 or nothing at 
the end of a fishery. On one day m 
1904 twelve boats manned exclusively 
by Arabs fishing from dawn till noon 
had an average catch per boat of 22,811 
oysters. Usually the men do not like to 
work on grounds that yield less than 15 
