i.] ANTECEDENTS. 9 



in point of time and by doing so they become 

 leaders of thought. They direct the intellectual 

 energy of the day into the channels they 

 opened ; it would have run in other channels 

 but for their labour. It is therefore due to 

 them, not that science progresses, but that her 

 progress is as rapid as it is, and in the direction 

 towards which they themselves have striven. 

 We must neither underrate nor overrate their 

 achievements. I would compare the small 

 band of men who have achieved a conspicuous 

 scientific position, to islands, which are not 

 the detached objects they appear to the vulgar 

 eye, but only the uppermost portions of hills, 

 whose bulk is unseen. To- pursue this meta- 

 phor ; the range of my inquiry dips a few 

 fathoms below the level at which popular 

 reputation begins. 



It is of interest to know the ratio which the 

 numbers of the leading scientific men bear to 

 the population of England generally. I obtain 

 it in this way. Although 180 persons only 

 we iv on my list, I reckon, as already mentioned, 

 that it would have been possible to have in- 



