Submarine Appliances And Their Uses
Deep Sea Diving, &c., &c.
Forfatter: R. H. Davis
År: 1911
Forlag: Siebe, Gorman & Co., Ltd.
Sted: London
Sider: 183
UDK: 626.02
A Diving Manual
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By means of a simple contrivance, those in the sponge fishing vessels are able to
survey the sea bed for patches of sponge. In clear water it is possible to see to a depth
of nearly thirty fathoms with this device. It consists merely of a copper or zinc
cylinder from two to four feet long by about twelve inches in diameter, treated inside
with lamp-black, a circular glass being fitted at one end and a pair of handles at the
other encl. The searcher pushes the cylinder about a foot under water, puts his head
into the open end, and as the vessel moves along he looks out for fruitful ground.
INTERNAL STRUCTURE OF SPONGE.
Fig. No. 80.
A, Vertical section of outer layer magnified 75 times ; p, pores or openings of canals
for conducting water which flows to a sacs ; e, canal for expulsion of water; g, early
stages of spores; B, sac, transversely divided, 800 diameters, showing sponge par-
ticles with cilia; C, sponge particles highly magnified; f, cilium; m, collar;«, nucleus ;
c, contractile vesicle.
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