TWO YEARS LATER. 45 



sciously, follow the guidance of the principle in ordinary 

 life. We are out walking, suppose, and a drop of rain 

 falls upon us ; now, there is no absolute reason why a 

 single drop falling from the sky should not light upon 

 us ; yet so certain are we that the odds against such an 

 event are enormous, that we conclude at once that rain 

 is falling over a wide space all around us. Or again, 

 suppose we meet some day five or six persons dressed 

 in a peculiar costume, and not forming one party we 

 conclude at once that there is to he some gathering of 

 such persons on the day in question. And so in a 

 thousand instances which will occur to every one. 



I conclude, then, with the utmost confidence that 

 for every meteor system encountered by the earth 

 there must be thousands which she does not en- 

 counter. 



And these multitudinous systems, illuminated as 

 they must be by the sun's rays, might very reasonably 

 be expected to become visible under favourable circum- 

 stances as, for example, when the sun is eclipsed. 

 Nay, knowing that the meteors travel in paths re- 

 sembling those of comets, and in some cases associated 

 in the most intimate manner with the paths of known 

 comets we may conclude that large numbers of meteors- 

 pass as close to the sun as some comets have been ob- 

 served to do, or even nearer, for observed comets form 

 but a small proportion of the total number of such 

 objects. Now, Sir John Herschel has shown that the 

 comet of 1843 passed so close to the sun that it must 

 have been subjected to a heat exceeding three and a 



