To make them.—A directing circle consisting of two hoops, kept apart by bits of wood, to which both the hoops are secured with packthread, is first made. The diameter of the hoops must be such as to permit of the pickets for the gabion being driven between the exterior of the one, and the interior of the other. The directing circle is then laid on a level piece of ground, and from seven to twelve pickets are driven at equal distances apart, between the hoops; the number of pickets depending on the size of the rods, or brushwood with which the basket-work is to be made. The circle is then raised, and fastened to the middle of the pickets, and the web is made above it, two or three rods being used at the same time; the workman twisting them round each other while he interlaces them with the pickets, striking down the web from time to time with a stick. The randing, or basket-work, is continued to near the top of the pickets, where it is secured with four gads, each one passed round one of the pickets and four or five of the rods, which should be from 8 to 10 feet long, and not more than half an inch in diameter. The gabion is then pulled up, the finished end is placed on the ground, and the directing circle being removed, the remainder of the web is completed and secured as before described.
Two men can make a gabion in three quarters of an hour, using about 80 rods for each gabion.
In forming the revetment, the gabions are placed touching each other with a slope of one quarter the height; the first row is surmounted with two rows of fascines side by side, and a second row of gabions rests on them.
SOD, OR TURF.
A revetment is sometimes made with sods of unequal sizes, called headers, and stretchers.
The headers are 1 foot 6 inches long, 1 foot wide, and about 4½ inches thick.
The stretchers are 1 foot wide, and long, and about 4½ inches thick.
Sometimes the sods are first cut all of the same dimensions—viz., 1½ foot long and 1 foot wide; this sod is then cut diagonally, across, so as to form two, and they are then all laid as headers. This saves nearly half the turf, and labour. The sods should be cut from good meadow land, previously mown, and watered; but the sods should not be laid or built when wet, because they would shrink in dry weather, and all the joints would open. The sod-work is laid with the grass downwards, either alternately headers, and stretchers, or two stretchers to one header; care being taken that the joints of no two rows fall immediately over one another, which is termed breaking joint. If the layers of sods are laid perpendicular to the slope, they will answer better than if laid horizontally. Each sod should have two or three pegs driven through it, to secure it to the work beneath. When the revetment is completed, the whole should be cut off smooth to the proper slope; a pair of hedge-clippers, or a cutting knife, will answer well for this purpose.
One man can lay 19 square yards of sod-work in eight hours, when the sods are brought to the spot, and require no previous trimming.
PLATFORMS.