Mortises for the thwarts were next cut and the middle thwart was forced into place, after the spall there had been removed. This required that the gunwales be spread slightly, thus increasing the amount of sheer somewhat. Much judgment was needed to do this correctly. The increase in the sheer lifted the ends slightly and put some rocker in the bottom toward the ends. The building frame was lifted out before the rest of the thwarts were placed; usually it was taken apart in the process. In forming the ends of the bark cover, the two sides were held together by a clothespin-like device made of two short, flat sticks lashed together. Increasing the beam at the gunwales by fitting the thwarts after the bark cover had been secured to the gunwales not only increased the sheer but decreased the depth of the canoe amidships as established by the posts placed under the gunwales in setting up. In order to retain the required sheer and the desired depth of side, the gunwales had been sheered up at the ends while being shaped, and had also been treated with hot water and hogged upward amidships by being staked out to dry into shape. The spreading of the gunwales tended to lift the ends of the bottom line, a condition that was controlled in two ways: the usual one apparently was to employ, in combination with a level bed, a building frame slightly wider than was desired for the finished bottom; the second way was to follow Malecite procedure and elevate slightly the middle of the building bed while employing a building frame the width of the finished bottom. The Algonkin procedure of spreading the gunwales during construction was that employed in the northwest and in the building of the fur-trade canoes, as will be seen. The amount of spread to be given the gunwales also affected the angle, or slope, at which the side stakes were driven on the building bed. Even so, some builders who spread the gunwales a good deal would set the stakes almost vertically, instead of at a slant, as this made sewing the side panels easier, particularly in large canoes and in canoes whose covers were made up of a large number of small pieces of bark. [Illustration: Figure 110 ALGONKIN, 2-FATHOM HUNTER'S CANOE, without headboards. Details of building frame, stakes or posts, gauge, and stem.]