EXPECTED METEORIC DISPLAY. 249 



was not seen. " There was not the slightest room," I wrote in 1872 

 (and, despite the opinions which have been since expressed by several 

 astronomers, I see no reason for changing my opinion), *' for question- 

 ing the accuracy of the calculations by which its path had been pre- 

 dicted. Astronomers were certain that, if undestroyed or undissi- 

 pated, the comet would follow the assigned path — as certain as a 

 station-master would be that a train would enter a station along the 

 line of rails assigned to it, unless some accident or mistake should 

 occur. But comets do not make mistakes, though, as we now see, 

 they are not free from accidents. This comet had already met with 

 an accident, being broken by some mischance into two parts, under 

 the very eyes of astronomers. Possibly in 1859 it met with further 

 misadventures. At any rate, something had happened to the comet 

 since its retreat in 1852. ' It is now,' Sir J. Herschel wrote in Feb- 

 ruary, 1866, ' overdue. Its orbit has been recomputed, and an ephem- 

 eris calculated. Astronomers have been eagerly looking out for its 

 reappearance for the last two months, when, according to all former 

 experience, it ought to have been conspicuously visible, but as yet 

 without success — giving rise to the strangest theories. At all events, 

 it seems to have fairly disappeared, and that without any such excuse 

 as in the case of Lexell's, viz., the preponderant attraction of some 

 great planet. Can it have come into contact or exceedingly close 

 approach to some asteroid as yet undiscovered? or, peradventure, 

 plunged into, and got bewildered among, the ring of meteorites, 

 which astronomers more than suspect ? ' " 



But, as I pointed out at the time, there was a convincing objection 

 against the first of these theories in the circumstance that, the two 

 comets into which Biela had separated being more than a million 

 miles apart when they passed out of view in 1852, it was not in the 

 least likely that both would be so far perturbed by asteroidal perturba- 

 tions as to remain thenceforward undiscoverable. " It would be a sin- 

 gular chance," I said (this was before November 27, 1872, when fresh 

 light, presently to be noted, was thrown on this object), " which 

 should bring one of these objects into collision with a minor planet, 

 or so near as to occasion an important disturbance. But, supposing 

 this to happen, then the fellow comet, not traveling in the wake of the 

 first, but side by side, would certainly have escajjed. For it must be 

 remembered that, although 1,250,000 miles is a very small distance 

 indeed by comparison with the dimensions of the solar system, it is an 

 enormous distance compared with the dimensions of the minor planets, 

 some of which have a surface not much greater than that of an Eng- 

 lish county. The minor planet occasioning the comet's disturbance 

 would presumably be one of the smallest, since it has not yet been 

 detected, and the newly-discovered planets are on the average much 

 smaller than those first detected. Now, the earth herself would have 

 no very marked influence on a comet or meteor passing her at a dis- 



