[7] VERRILL—DREDGING APPARATUS OF U.S. FISH COMMISSION. 71 
TOWING-NETS. 
Figure 8. 
The rings of the towing-nets generally used by the Fish Commission 
are made of 4-inch brass wire, with three loops of brass wire securely 
soldered to the ring, at equal intervals. Other modes of attaching the 
lines are equally good, and often used by us. The nets are usually made 
of rather open and strong “embroidery canvas.” Sometimes, for special 
purposes, coarse: Swiss muslin is used, when they are to be drawn by a 
row-boat. ‘Crinoline” is also suitable for these nets. The nets should 
be made deep and rather “full.” We have not found any special ad- 
vantage in attaching a bottle with its neck in the bottom of the net, as 
recommended by some writers. We have used several sizes of rings, 
varying from 8 to 14 inches in diameter. The smallest sizes can alone 
be used when a steamer or vessel has much headway. 
THE CHECK-STOP. 
Figure 9. 
This arrangement was devised by Capt. L. A. Beardslee, for use on 
the “Blue Light,” in 1873. Its purpose is to put the strain of the drag- 
rope (B) upon a weaker rope (C), which may be broken so easily, in case 
the dredge or trawl catches upon rocks, as not to cause damage to the 
apparatus, and at the same time to give sufficient warning to allow the 
slack of the drag-rope to be paid out before the headway of the vessel 
can be stopped. It has proved to bea very useful and simple expedient 
for these purposes. The figure shows the arrangement so well that no 
further description is necessary. 
THE CRADLE SIEVE. 
Figures 10, 11. 
This form of sieve was devised by the writer in 1872. It was so 
constructed as to afford the means of rapidly washing out the large 
quantities of mud often brought up by the dredge and rake-dredge, 
and at the same time to keep the mud and water off the deck as much 
as possible. It consists of two wooden end-pieces, in shape forming 
rather more than half a cirele, united by two narrow, wooden, side- 
pieces set into the end pieces so as to leave a flush surface. The 
outside covering consists of two thicknesses of wire netting; the inner 
one with meshes of {5 inch or less, the outer one of stout galvanized-iron 
wire, with 3-inch meshes. The outer netting is only to afford support and 
protection to the inner one. The outer netting is nailed to the edges of 
the wooden end-pieces, and to the side-pieces, and is farther secured by 
a strip of hoop-iron nailed over the edges all around. The inner lining 
of fine wire netting is tacked to the wooden ends and side-pieces, on the 
inside, so that it can easily be renewed when worn out. <A strip of wood 
