The computation of the power of the Waves is less satisfactory. While only the average power of the wind, and the average height of the tide, were taken before, now the extreme height of the waves is used, for they are made to rise ten feet above the level of the sea, to which, adding ten more for depression, we have twenty feet, or the extreme height of a wave. Indeed, the power of the waves, which is produced by the wind blowing obliquely and at disadvantage upon the water, is made to be, not only three thousand times greater than that of the tide, but one hundred times greater than that of the wind itself, meeting its object at right angles. Moreover, this power is measured by the area of the vessel, and not by its length mainly, and it seems to be forgotten that the motion of the waves is chiefly undulatory, and exerts a power only within the limits of a vibration, else the very continents, with their extensive coasts, would soon be set adrift. Finally, there is the power to be derived from Sunshine, by the principle on which Archimedes contrived his burning-mirrors, a multiplication of mirrors reflecting the rays of the sun upon the same spot, till the requisite degree of heat is obtained. The principal application of this power will be to the boiling of water and production of steam. So much for these few and more obvious powers, already used to a trifling extent. But there are innumerable others in nature, not described nor discovered. These, however, will do for the present. This would be to make the sun and the moon equally our satellites. For, as the moon is the cause of the tides, and the sun the cause of the wind, which, in turn, is the cause of the waves, all the work of this planet would be performed by these far influences. “We may store up water in some eminent pond, and take out of this store, at any time, as much water through the outlet as we want to employ, by which means the original power may react for many days after it has ceased.... Such reservoirs of moderate elevation or size need not be made artificially, but will be found made by nature very frequently, requiring but little aid for their completion. They require no regularity of form. Any valley, with lower grounds in its vicinity, would answer the purpose. Small crevices may be filled up. Such places may be eligible for the beginning of enterprises of this kind.” The greater the height, of course, the less water required. But suppose a level and dry country; then hill and valley, and “eminent pond,” are to be constructed by main force; or, if the springs are unusually low, then dirt and stones may be used, and the disadvantage arising from friction will be counterbalanced by their greater gravity. Nor shall a single rood of dry land be sunk in such artificial ponds as may be wanted, but their surfaces “may be covered with rafts decked with fertile earth, and all kinds of vegetables which may grow there as well as anywhere else.”