John Herschel, for example, speaks of meteors as "bodies extraneous to our planet, which only becomes visible when in the act of grazing our atmosphere." The idea, however, is wholly erroneous, as we shall presently see. Another remarkable question which was asked soon after the occurrence of the November shower, served still more clearly to exhibit the indistinctness of the views commonly held; meteors having been seen at Cape Town at the same hour (actual time) as in England, it was asked how the same meteors could be seen in both places, unless they had travelled as satellites round the earth? An eminent chemist, who has lately published a work on meteors, speaks of the received opinion of the cosmical origin of meteors, as, after all, merely conjectural, and he evidently leans towards the theory that they are satellites of the earth. Lastly, in Guillemin's "Heavens," a view is expressed (and illustrated by an elaborate figure), which is wholly inconsistent with observed appearances. I refer to the notion that a single stream of bodies could give rise to both the November and August showers. It is evident, therefore, that there is room for a careful examination of the actual state of things during the occurrence of the November shower. By considering the position of England on the rotating earth, during the time of the display, we shall be able to form clear views on this point. I must first, however, mention briefly the true meaning of the existence of a "radiant point." Once this phenomenon is established, all doubt whatever respecting the cosmical origin of a shooting star shower disappears. It is not true that the theory of a cosmical origin is now a conjectural one; it is established on a thoroughly firm basis. The phenomenon of a radiant point proves in fact this, that the paths in which the meteors intersect our atmosphere, are all parallel in space throughout the time that the shower is visible. Now the display lasting several hours, during which the earth moves through a large angle round her axis of rotation, it is quite clear that the display cannot have a terrestrial origin, since if it had, the direction of the shooting stars might be expected to change correspondingly, and would certainly not change after so artificial a manner that for several places at once the effects of the earth's rotation would be exactly compensated. An equatorial telescope, for instance, is made by clockwork always to point to the same star, but we know that no telescope fixed at random and moved at a random rate would do so. Just, therefore, as a person seeing the same star for a considerable time through the tube of a telescope, knows certainly that he is looking through an equatorial rendered artificially independent of the earth's rotation-so, seeing shooting stars moving always from a fixed point among the stars, we know for certain that the direction of their motion is independent of the earth's rotation, and therefore-there being no possibility of an artificial arrangement corresponding to that of the equatorial-that the shooting stars come from external space. The notion of a lunar origin, and the satellite theory of meteors are similarly overthrown, though indeed, at the present day, no competent person entertains either of these views, which are for other reasons, wholly untenable. When the occurrence of a "radiant point" is coupled with "annual periodicity and independence of geographical position, referring us at once to the place occupied by the earth in its annual crbit," the most sceptical (or, in this case, we must say those least able to appreciate the mathematical demonstration of the meaning of a radiant point), must be led "directly to the conclusion that the earth is liable to encounters or concurrences with meteor streams in their progress of circulation round the sun." It must be mentioned that the earth's motions have their effects upon the apparent motion of bodies moving in space. The motion of rotation, however, may be neglected in comparison with the motion of revolution and the proper motion of meteoric bodies. Travelling in space, under the sun's attraction, they cannot, at the moment of encountering the earth, be moving with a less velocity than that due to a body moving circularly round the sun at the earth's distance (a rate very slightly less than the earth's) and they may have a velocity nearly half as great again as this. Between these values their velocity necessarily lies. Further, their velocity, relatively to the earth, must lie somewhere in value between the sum and difference of their actual velocity and the earth's, or between zero and about forty-five miles per hour; the first value giving the extreme case of meteors travelling in the same direction, and at the same rate as the earth; the second giving the case of meteors travelling in a parabolic orbit, and encountering the earth directly, just when they are in perihelion. I have mentioned these limits and considered the nature of meteors' motion relatively to our earth, because it is on this relative motion that the position of the "radiant point " depends. If we suppose the earth reduced to rest, and her motion, reversed, added to the motion of the meteoric stream, we get the same relative motion, and the same radiant point as under the actual circumstances of the case. For clearness of explanation let us suppose this to happen, and that on the night of November 13-14 the earth's motion of revolution is non-existent (her motion of rotation continuing, however), and that the meteors are sweeping towards her from their radiant point (i.e. at a rate and in a direction resulting from the |