42. Variable or regulating lashing. By laying the piece, a f,
horizontally, it can be slipped along the rope, b; by raising or
lowering this, we shall raise or depress the weight, c, the cord, b,
running over the two pulleys, d, from the piece, a f, in the direction
shown in the figure. The friction of the cord, b, passing through the
hole, e, sufficiently fixes the piece, a f, and holds the weight, c,
securely.