


104. LIVERPOOL BIOLOGICAL SOCIETY. 
by which the closing cord is made fast to the lower part of 
the lock. 
The opening cord consists of two links of brass (c., d.) 
each two feet in length, at the end of which is a loop 
similar to that just mentioned (fig. 1, 7.) for attachment to 
the lock. There is also a cord or chain (n.) of a little over 
three feet in length, the function of which is merely to 
prevent the links (c., d.) from hanging loose when the net 
is brought up closed. 
2. The Lock. 
This portion of the apparatus is destined to enable the 
naturalist, by means of weights, known as “‘messengers,” 
which slide down the line, to let go the closing and 
opening cords in succession. One half of it is shown from 
the median side in fig. 5, whilst a perspective view of the 
whole is given in fig. 6. It is seen to consist of two . 
corresponding halves (a., a’.), each of which is a solid brass : 
casting of oblong shape, with a prominence at one end. 
Each portion has a groove (/.,/.) so arranged that when 
the two are applied to each other an oblique tunnel is 
produced, in which hes the rope by which the apparatus is 
towed. ‘The rope having been laid in the groove of one of 
the pieces, is held in place by two bolts (fig. 7), the lower 
threaded portion being passed through the holes (e., e’.) 
so that when a nut (like those in fig. 6, 7., 2.) is applied to 
the outside and screwed down, the hooks on the bolts grip 
the rope with the required degree of firmness. The other 
half of the lock is then placed o¥sr the rope and secured 
by similar nuts working upon the upper threaded portions. 
The lock can thus be made perfectly secure upon any part 
of the rope, and furthermore the thickness of the rope may 
vary within pretty wide limits. 
In the left hand margin of each half of the lock is seen 

