a very high tide, but a star of the same description, which, in its elliptic course about the sun, directly struck the earth. Let us examine closely what would be the effect of such an event.

Let us conceive a solid body proceeding in a straight line with a certain rapidity, and upon which from the outset another much smaller body had been merely placed. These two bodies, although not fastened together, will not separate in their progress, because the force which moves them will have gradually and from the commencement imparted equal velocities to them. But let us suppose that an insurmountable obstacle suddenly presents itself in the way of the first body, and stops it instantly; the fore part of the surface, the parts struck, are, strictly speaking, the only parts whose velocity is directly destroyed by the obstacle; but as all the other parts are intimately attached to the firstas, from our hypothesis, the body is solid-the whole of that body will stop.

It will not be so with the small body which we have simply laid upon the first. This we may stop without the other, to which nothing attaches it, unless it may be a slight degree of friction; and it will experience no effectlose none of its celerity. By virtue of this acquired and undiminished velocity, the small body will separate itself from the large one, and will continue to move in the original direction until the moment when its own weight shall