228 Chronicles of Science. [April, 



in space facing the earth, as it travelled onwards at the rate of 

 65,000 miles an hour would have seen its northern pole well 

 within the darkened half-disc ; England would have heen hrought 

 into view before Cape Town, — England more than an hour before, 

 Cape Town nearly an hour after, local midnight. Now, if between 

 our observer and the advancing earth, there were situate a plane of 

 meteors inclined 19° to the ecliptic, he would have seen the lower 

 or southern half of the disc plunging first through the plane, 

 the upper, or northern half, appearing last. The fact, then, that 

 some ten minutes or a quarter of an hour elapsed between the max- 

 imum displays at Cape Town and England, is fully accounted 

 for. The earth in that time travelled forwards some 14,000 miles, 

 but its motion relatively to a plane inclined 19° to the ecliptic would 

 be only one-third of this, or (roughly) about enough to shift the 

 plane from Cape Town to England. The fact that the display was 

 somewhat less rich at Cape Town is explained by the circumstance 

 that the earth's surface encountered the plane less directly on the 

 southern hemisphere, where contact first took place, than on the 

 northern hemisphere, which was bowed down towards the plane. 

 The fact that the display lasted nearly three hours shows that the 

 thickness of the meteor zone cannot be less than 60,000 miles. 



The fact that no display was seen in America does not prove, 

 as many have supposed, that the extent of the zone is small. It 

 follows conclusively, from the results just examined, that America 

 was on the following (or sheltered) hemisphere of the earth during 

 the whole time that she occupied in plunging through the meteor- 

 zone. Therefore, the invisibility of the display in America affords 

 additional evidence respecting the thickness of the zone, showing 

 that it cannot greatly exceed the above-named estimate, but supplies 

 no evidence whatever as to the extent of the zone. 



From the fact that England was far advanced upon the earth's 

 forward hemisphere at the epoch of maximum display, it is demon- 

 strable that every meteor which then made its appearance above 

 the horizon of any place in England, must have reached the earth's 

 surface, or have been dissipated in the atmosphere, — unless we 

 assume a height of several hundred miles for the meteors. Even 

 this assumption, which is opposed to all evidence resulting from 

 exact observation, would only allow the escape of a few meteors, 

 seen low down towards the north-west. The fact that, for every 

 meteor which grazes our atmosphere, hundreds must enter it in a 

 direct line for the earth's surface, seems to have escaped the notice 

 of many who have theorized on the subject. It shows that for all 

 but the largest meteors our atmosphere acts as an efficient " buffer," 

 deadening their impulse so thoroughly that they are vaporized by 

 the heat equivalent to their lost velocity. 



The spectrum-analysis of the November meteors appears to 



