166 BULLETIN OF THE UNITED STATES FISH COMMISSION. 
tally, these being pushed to their place below the surface of the water 
by means of a forked stick. The upper part of the weir is ordinarily of 
more loosely woven brush placed perpendicularly, the upper extremities 
extending to a point 2 or 3 feet above high water, and as the rise and 
fall of the tide averages 20 feet, and in spring tides nearly 30, the 
amount of material used is considerable. Formerly only pine, spruce, 
and other soft wood was employed, but in the larger and more exposed 
weirs hard wood is now almost invariably substituted, and the size of 
the posts and stringers is considerably increased. Of late some of the 
fishermen are replacing the brush by heavy netting in that portion of 
the weir which is exposed at low water. 
The principle upon which the weirs are constructed varies consider- 
ably, according to the locality in which they are to be placed. The 
principal forms are known as bar weirs, channel weirs, shore weirs, and 
patent weirs. The first named is so placed that a ledge runs across its 
mouth, this being covered by the tide to a depth of 8 or 10 feet at 
high water, but gradually approaching the surface as the tide recedes 
and being left dry at half ebb, thus effectually preventing the escape of 
the fish. Channel weirs are built in the strong currents between the 
islands and ledges or between the main-land and an island. They have 
brush wings running out to either shore to turn the fish toward the 
mouth of the weir, which is so constructed that they find difficulty in 
escaping. The shore weirs vary endlessly in shape, but in most cases a 
wing extends diagonally outward for several yards from the mouth of 
the weir, which is usually just at the edge of the water-line at low wa- 
ter, another often running diagonally from the opposite side of the 
mouth to the shore, while the shore forms the inner side, the fish being 
retained in the weir proper, which resembles slightly a semicircle in 
shape. The patent weir is constructed on a principle similar to that of 
the pound-nets so extensively employed in the Great Lakes and along 
the southern shores of New England. It consists of a leader of brush 
extending at right angles to the shore into 15 or 18 feet of water at low 
tide, with an inclosure for the fish from 20 to 50 feet across at the outer 
extremity. Where the bottom is hard and stakes can not be driven 
ballasted weirs are built. These are similar in form to those already 
described, but have the stakes strongly secured and braced to a large 
platform, corresponding in shape to the bottom on which it is to be 
placed, this being heavily weighted with stones and sunk into place, 
the stones holding it securely against the current. Nearly half of the 
weirs built at Deer Island during the present season are of this kind. 
From year to year the material for building the weirs has become more 
scarce, and, consequently, more expensive. As a result, the fishermen 
now usually take out the brush above the line of low water and keep it on 
shore during the winter, replacing it when the weir is put in order the fol- 
lowing spring. A weir properly constructed will last for five or six years, 
the stakes at this time usually being so badly worm-eaten that they are 
