The canoe was built on a level building bed, in most instances apparently, with the ends of the building frame blocked up about an inch. It seems possible, however, that narrow bottom canoes may have been built with the bed raised 2 or 3 inches in the middle, rather than employing a narrow building frame. The construction of the building frame was the same as among the western Indians and as described in Chapter 3. [Illustration: Figure 83 ST. FRANCIS-ABNAKI CANOE FOR OPEN WATER, a type that became extinct before 1890. From Adney's drawings of a canoe formerly in the Museum of Natural History, New York. Details of Abnaki canoes are also shown.] In preparing the ribs, a common practice was the following: Assume, for example, that there are 10 ribs from the center to the first thwart forward; these are laid out on the ground edge-to-edge with the rib under the center thwart to the left and the rib under the first thwart to the right. On the rib to the left the middle thwart is laid so that its center coincides with that of the rib, and the ends of the thwart are marked on the rib. The same is done to the rib on the far right, over which the first thwart is laid as the measure. On each side of the centerline the points marking the ends of the thwarts are then joined by a line across the ribs, as they lie together, to mark the approximate taper of the canoe toward the ends, at the turn of the bilge. Each rib is taken in turn from the panel and with it is placed another from the stock on hand to be set in a matching position on the other side of the middle thwart, toward the stern; the pair, placed flat sides together, are then bent over the knee at, or outside of, the marks or lines. The ribs in the next portion of the canoe's length are shaped in the same manner, using the lengths of the first and second thwarts as guides. Thus, the ribs are given a rough, preliminary bend before being fitted inside the bark cover and stayed into place to season. This method allowed the bilge of the canoe to be rather precisely determined and formed during the first stages of construction. At the ends, of course, the ribs are sharply bent only in the middle. Since the full thwart length makes a wide bottom, by setting the length of the rib perhaps a hand's width less than that of the whole thwart, the narrow bottom is formed. The rough length of the ribs was twice the length of the thwarts nearest them. Hackmatack was used for thwarts by the St. Francis Indians, rock maple being considered next best. Cedar was first choice for ribs, then spruce, and then balsam fir. Longitudinals were cedar or spruce. All canoe measurements were made by hand, finger, and arm measurements. Basket ash strips were often used in transferring measurements. [Illustration: Figure 84 MODEL OF A ST. FRANCIS-ABNAKI CANOE UNDER CONSTRUCTION, showing method of moulding ribs inside the assembled bark cover.]