There is only one possible way of explaining the floating power of birds, and that is by associating it with the rapid motion acquired originally by wing flapping, and afterward husbanded, so to speak, by absolutely perfect adjustment and balancing. To this the answer is often advanced that it implies ignorance of the laws of dynamics to suppose that rapid advance can affect the rate of falling, as is implied by the theory that it enables the bird to float. Now, as a matter of fact, a slight slope of the wings would undoubtedly produce a raising power, and so an answer is at one obtained to this objection. But I venture to assert, with the utmost confidence, that a perfectly horizontal plane, advancing swiftly in a horizontal direction at first, will not sink as quickly, or anything like as quickly, as a similar plane let fall from a position of rest. A cannon-ball, rushing horizontally from the mouth of a cannon, begins to fall just as if it were simply dropped. But the case of a horizontal plane is altogether different. If rapidly advancing, it passes continually over still air; if simply let fall, the air beneath it yields, and presently currents are set up which facilitate the descent of the flat body; but there is no time to set up these aerial movements as the flat body passes rapidly over still air. As a matter of fact, we know that this difference exists, from the difference in the observed behavior of a flat card set flying horizontally through the air and a similar card held horizontally and then allowed to fall. I believe the whole mystery of aerial flotation lies here, and that as soon as aerial floating machines are planned on this system, it will be found that the problem of aerial transit--though presenting still many difficulties of detail--is, nevertheless, perfectly soluble.--_R.A. Proctor, in Newcastle Weekly Chronicle_. * * * * * AN ASSYRIAN BASS-RELIEF 2,700 YEARS OLD. There was exhibited at the last meeting of the Numismatic and Antiquarian Society, in Philadelphia, on May 7, an object of great interest to archaeologists, with which, says _The Church_, is also connected a very curious history. It appears that about forty years ago a young American minister, Rev. W.F. Williams, went as a missionary to Syria, and he visited among places of interest the site of ancient Nineveh about the time that Austin Henry Layard was making his famous explorations and discoveries; he wrote to a friend in Philadelphia that he had secured for him a fine piece of Assyrian sculpture from one of the recently opened temples or palaces, representing a life size figure of a king, clad in royal robes, bearing in one hand a basket and in the other a fir cone. One portion of the stone was covered with hieroglyphics, and was as sharply cut as though it had been carved by a modern hand instead of by an artist who was sleeping in his grave when Nebuchadnezzar, King of Babylon, was yet an infant.