1 64 THE BORDERLAND OF SCIENCE. 



never carry to other systems any appreciable portion of 

 the velocity it had acquired while traversing the system 

 of which Sirius is the ruling centre. 



Our difficulty remains, then, still unexplained. But 

 before searching anew for an explanation, we may note 

 another very curious inference from what has already 

 been shown. We have seen that meteoric bodies which 

 travel with such enormous velocities as have been noted 

 in some instances, must certainly have come from the 

 domain of another sun than ours. But precisely as 

 meteors approach our sun, and then pass away for ever, 

 so meteors that come to us from the domains of other 

 stars must, in many instances, have passed into those 

 domains from the domains of yet other stars. Nor can 

 it be regarded as likely in the nature of things that 

 only two or three such voyages have been per- 

 formed. On the contrary, it must be regarded as 

 almost certain that, in some cases, meteors traverse 

 inter-stellar spaces many hundreds of times, visiting 

 each time a different stellar domain, and perhaps 

 even completing more than one circuit around some 

 stars. Remembering that the least interval in which 

 a body can pass from the domain of one star to that of 

 another is about a million of years, we begin to recog- 

 nise the wonderful antiquity of many of those bodies 

 which have been thought fit emblems of all that is 

 transient and perishable. 



But it is when we seek for an explanation of the 

 excess of velocity that we are led to the most startling 

 conclusion. Let it be remembered that this excess of 



