The November Shooting Stars. 451 



consequences. In the first place, then, supposing the earth 

 to plunge, in its yearly circuit, into a uniform, ring of innu- 

 merable small meteor-planets, of such breadths as would be 

 traversed by it in one or two days; since during this small 

 time the motions, whether of the earth or of each individual 

 meteor, may be taken as uniform and rectilinear, and those of 

 all the latter (at the place and time) parallel, or very nearly 

 so, it will follow that the relative motion of the meteors referred 

 to the earth as at rest, will be also uniform, rectilinear, and 

 parallel. Viewed, therefore, from the centre of the earth (or 

 from any point in its circumference, if we neglect the diurnal 

 velocity as very small compared with the annual) they will all 

 appear to diverge from a common point, fixed in relation to the 

 celestial sphere, as if emanating from a sideral apex/' 



Here Sir John Herschel refers us to his very interesting 

 remarks in an early chapter on the subject of " celestial per- 

 spective " — "that branch of the general science of perspective 

 which teaches us to conclude, from a knowledge of the real 

 situation and forms of objects, lines, angles, motions, etc., with 

 respect to the spectator, their apparent aspects as seen by him 

 projected on the imaginary concave of the heavens ; and vice 

 versa, from the apparent configurations and movements of 

 objects so seen projected, to conclude, so far as they can be 

 thence cou eluded, their real geometrical relations to each other 

 and to the spectator. - " He then proves that in celestial per- 

 spective " every straight line (supposed to be indefinitely 

 prolonged) is projected into a semicircle of the sphere, that, 

 namely, in which a plane passing through the line and the eye, 

 cuts its surface. And every system of parallel straight lines, 

 in whatever direction, is projected into a system of semicircles 

 of the sphere, meeting in two common apexes, or vanishing 

 points, diametrically opposite to each other." This digression 

 is to explain what is meant by a " sidereal apex." And here 

 let me anticipate. On the morning of Nov. 14th, when I saw 

 the meteors emanating from a point at some distance above the 

 horizon, when I observed many of them mounting overhead, 

 and the whole display retaining the form of a canopy, while 

 tending as if to some point far below the opposite horizon, I 

 felt that perspective had in some way a great deal to do with 

 their aspect, and that I should not think of them as of sky 

 rockets shot in real curves over the house ; but it required the 

 luminous words of Sir John Herschel to place the matter in 

 an intelligible form. Let us now take up the thread of his 

 argument. 



The shooting stars, he says, ought to appear to diverge 

 from a common point ; and he proceeds to tell us, " This is 

 precisely what actually happens. The meteors of the 12 — 14th 



