a certain quantity of timber bound together with rafters athwart, and put into a river to be conveyed down the stream; and even sometimes to carry burdens down a river with the stream.

FLOAT Boards, those boards fixed to water wheels of under-shot mills, serving to receive the impulse of the stream, whereby the wheel is carried round. See the articles WHEEL and MILL.

It is no advantage to have too great a number of float-boards; because, when they are struck by the water in the best manner that it can be brought to come against them, the sum of all the impulses will be but equal to the impulse made against one float-board at right-angles, by all the water coming out of the penstock through the opening, so as to take place on the float-board. The best rule in this case is to have just so many, that each of them may come out of the water as soon as possible, after it has received and acted with its full impulse. As to the length of the float-board, it may be regulated according to the breadth of the mill. See MILL.

FLOATS for Fishing. See FISHING Floats.