178 THE BORDERLAND OF SCIENCE. 



Herschel has shown) may afford perhaps the most 

 satisfactory solution of the difficulties we have been 

 considering. 



The seed-bearing meteors of Sir W. Thomson, if 

 their existence be admitted, must be regarded as 

 holding an intermediate position between the two 

 classes of meteors above referred to. They have 

 neither been for all ages unattached wanderers through 

 space, nor certainly have they been rejected from the 

 fiery interior of a sun such as ours. In fact, Sir W. 

 Thomson tells us very definitely what they are, they 

 are the fragments of worlds which have been destroyed 

 by collision. It is desirable to present Sir W. 

 Thomson's reasoning in his own words (according to 

 the fullest reports), because full justice has not always 

 been done to him when his startling hypothesis has 

 been described or summarised. The theory is amazing 

 -enough even as he presents it; but it is rendered 

 utterly absurd by some of the modifications which it 

 has received in the mouths of exponents. 



Let us first consider how the theory was suggested. 

 The questions which have recently been raised 

 xespecting the origin of life could scarcely pass 

 unnoticed in a review of the scientific work of the 

 year 1872. Accordingly, Sir W. Thomson, as President 

 of the British Association, seemed invited to their 

 discussion. 'How did life originate,' he asks, 'upon 

 the earth ? Tracing the physical history of the earth 

 backwards, we are brought to a red-hot melted globe 

 on which no life could exist. Hence, when the earth 



