180 THE BORDERLAND OF SCIENCE. 



of solid matter fall on the earth. Whence come 

 these fragments ? What is the previous history of any 

 one of them ? Was it created in the beginning of 

 time an amorphous mass ? This idea is so unacceptable 

 that, tacitly or explicitly, all men discard it. It is 

 often assumed that all, and it is certain that some, 

 meteoric stones are fragments which had been broken 

 off from greater masses and launched free into space. 

 It is as sure that collisions must occur between great 

 masses moving through space, as it is that ships 

 steered without intelligence directed to prevent 

 collision could not cross and recross the Atlantic for 

 thousands of years with immunity from collisions. 

 When two great masses come into collision in space, 

 it is certain that a large part of each is melted ; but 

 it seems also quite certain that, in many cases, a large 

 quantity of debris must be shot forth in all directions, 

 much of which may have experienced no greater 

 violence than individual pieces of rocks experience in 

 a landslip or in blasting by gunpowder. Should the 

 time when this earth comes into collision with another 

 body, comparable in dimensions to itself, be when it is 

 still clothed as at present with vegetation, many great 

 and small fragments, carrying seed and living plants 

 and animals, would, undoubtedly, be scattered through 

 space. Hence, and because we all confidently believe 

 that there are at present, and have been from time 

 immemorial, many worlds of life besides our own, we 

 must regard it as probable in the highest degree that 

 there are countless seed -bearing meteoric stones 



