The mode of construction is perfectly simple. The labour is divided between the sexes: the women cut large sheets of bark from the birch-trees, scrape and smooth them, and then sew them together, so as to form the outer skin, or “cloak” as it is called, of the canoe. Meanwhile the men are making the skeleton of strips of white cedar-wood, and binding them into shape with thongs made of the inner bark of the same tree, just like the “bass” of our gardeners. The “cloak” is then gradually worked over the skeleton, sewn into its place, and the canoe is finished. A figure of this canoe, as completed, is given in the same illustration as that which represents various forms of boat, page 7. The last improvement is that which was caused by the necessity for large vessels, when planks or iron plates were fastened over the skeleton. But, in all these cases, the vessel is built on the principle of the thorax of a vertebrate animal, that of the whale or a fish being an admirable example. It only needs to take the skeleton of a whale, turn it on its back, and the ribs will be seen to form an almost exact reproduction of those of any ship being built in the nearest dockyard. [Illustration: RIBS OF FISH. RIBS OF SHIP.] I have now before me the spine and ribs of a herring. The fish was over-boiled, and the flesh fell off the bones as it was being lifted out of the dish, leaving most of the ribs in their places. When held with the spine downwards, and viewed from one end, the resemblance to the framework of a ship is absolutely startling, the ribs representing the beams, and the spine taking the place of the keel. I have also before me a sketch representing a section of a Fijian canoe, and it is remarkable that even the very curve of the ribs of the herring is reproduced in those of the canoe. Whether the Fijians derived this peculiar and beautiful curve from the ribs of a fish I cannot say, but think it very likely. * * * * * A STILL greater improvement in ship-building now comes before us, and this also has been anticipated both in the animal and vegetable kingdoms. There are so many examples of this anticipation that I can only give one or two. The improvement to which I refer is that which is now almost universally employed in the construction of iron ships, namely, the making the outer shell double instead of single, and dividing it into a number of separate compartments. Putting aside the advantage that if the vessel were stove, only one compartment would fill, we have the fact that the ship is at the same time enormously strengthened and very light in proportion to her bulk. [Illustration: SECTION OF ELEPHANT SKULL. TRANSVERSE SECTION OF IRON SHIP. STELLATE TISSUES. LONGITUDINAL SECTION OF IRON SHIP.]