254 NATURAL SCIENCE [October 
tion from the place where such are found. Therefore, at the fish- 
ing ground, fishermen do not throw away any oily substance out of 
the boat; moreover, they keep very quiet, uttering no word. 
The sweep seine.—There are many kinds of this seine, 
different in structure as well as in the method of using. I 
shall describe some nets of special interest. 
The double floats seine (Fig. 1)—This is simply a long, narrow 
net, of which the height is greatest in the middle and decreases gradu- 
ally towards either end. The length of the rope at both upper and 
lower margins of the net is 600 feet. This net has a very long and 
narrow netting added to its upper margin like a roof, to prevent the 
fish from leaping out of it. The narrow netting has its own floats on 
the free margin, hence the seine has two rows of floats. This special 
structure makes the net adapted for the capture of the mullet. When 
the net is in use, a small boat constantly attends to the roof-like net- 
ting to make it keep the right position and not to collapse; this is done 
by binding two or three floats together, as the seine is gradually drawn 
towards the shore and the two wings approach each other more and 
more. This seine is used by a boat manned by seven men to encircle 
a shoal of fish, and it is done under directions from a watch-tower 
on shore. When the seine is completely put out, it is dragged in by 
about thirty men on shore. This net can be used only in flat sandy 
shores. 
The sweep-seine fishery with a sunken rope.—In certain parts of 
Central Japan a peculiar method is employed. During the night a 
big straw rope is sunk to the bottom of the sea at right angles to 
the coast line, and fishermen wait silently on land for the approach 
of fish with a boat ready in which a sweep seine is loaded. It is 
said that when a shoal of fish approaches, some fish are frightened by 
the sunken rope and leap out of water. The fishermen hearing 
the sound of the leaping fish, jump into the boat and hastily encircle 
the seine. 
The dip net (Fig. 2)—Of this net also there are many 
kinds. It is used generally on rocky ground. It is rectangular 
or square in shape, and is mostly of a large size (some nets measure 
about 240 feet by 120 feet). The net is sunk at a convenient 
place in the route of migration of the fish. In some cases the net is 
