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the weight of men crossing, a few stakes, C D,fig. 15, with forks left near their heads, may bethrust down, through the branches, to the bot-tom of the river, and hitched to the mainbranches of the trees; or the force of the cur-rent may be made to yield vertical support tothe communication, by applying a few planks,forming a plane, A B, fig. 15, inclined to thesurface of the current in an angle of about 50°,by which that power which, in the flying bridge,acts horizontally, may be obtained vertically,in a manner that will greatly add to the stabi-lity of the rough structure.

If no communication can be established withthe further bank, fell two large trees, and oneof middling size, and place them in the water.Take one of the former—place it as representedby A B in fig. 14, and confine it in that positionby a rope to the bank c; press the heel A ofthe first tree down in the water, by placing twoor three men on it, in order to raise the head asmuch as possible during the following operation:— Lash one end D of the small tree D E uponthe tree A B, at about a fourth of its lengthfrom the top, the end E abutting on the bank;float the remaining tree downwards, and placeit’s heel upon the second tree, at a few feet fromit’s junction with the first, by keeping down the