Hence a reason may easily be given, why water from the depths of the ocean, ascending into the summits of the mountains, bursts from them in the form of rivers and flows again into the ocean; so does Nature offer to us the spectacle of perpetual motion. Hence I say, they do not well explain who allege that the water ascends to these heights through the pores of the earth, as a fluid ascends in narrow tubes above the surface of the fluid surrounding; for if such were the explanation of the thing, they would never be able to demonstrate it; for the water so raised to a height from the bosom of the earth, falls again, whereas we see that the fluid in these narrow tubes, although slightly elevated above the surrounding surface, never issues from their orifices and falls into the fluid below. The following is then the more feasible explanation. It is known that water in which much salt is held in solution is heavier than fresh water; now sea-water, as is sufficiently evident from the taste, contains many saline particles; consequently it is heavier than spring or river water; so that it is credible that the earth acts like a filter through the pores of which only fresh water can pass, the saline particles being left behind, and this increases the weight of the water; the fresh water must ascend much higher on account of the immense profundity of the ocean, as it is forced to the highest peaks of the mountains by the presence of the sea-water; and thence, not being able to ascend any higher, it falls in rivers. P. Christopher Scheiner That an earnest belief in the possibility of Perpetual Motion has not been confined entirely to scientific tyros and enthusiastic dreamers, is sufficiently attested by the fact that a respectable number of eminent scientists, many of whom had done great service in their scientific labors, have believed in such possibility. Among these is to be mentioned P. Christopher Scheiner, a German, born 1575, and died 1650. He was a mechanic of note; in his day made valuable additions to what was known of light and optics, invented the Pantagraph, discovered solar spots, besides benefiting mankind by many other distinguished fruits of his genius. The subject of Perpetual Motion claimed some of his attention. He wrote in defense of its possibility. The substance of what he said, translated into English, is as follows: Let the centre of the universe then, or of gravity, be A, and the gnomon A B C, of which the extremity A is pierced and traversed by an axis going through the centre of the world, so that it may turn and revolve freely and easily around the said centre; to the other extremity of the gnomon, C, let a phial full of water be attached.