188 A Physicist on Evolution. 



revelation, lest it should endanger wliat they are pleased to con- 

 sider theirs. 



The lode of discovery once struck, those petrified forms in 

 which life was at one time active, increased to multitudes and 

 demanded classification. The general fact soon became evident 

 that none hut the simplest forms of life lie lowest down, that as 

 we climb higher and higher among the superimposed strata more 

 perfect forms appear. The change, however, from form to form 

 was not continuous — but by steps, some small, some great. " A 

 section," says Mr. Huxley, " a hundred feet thick will exhibit at 

 different heights a dozen species of ammonite, none of which 

 passes beyond its particular zone of limestone, or clay, into the 

 zone below it or into that above it." In the presence of such 

 facts it was not possible to avoid the question, Have these forms, 

 showing, though in broken stages and with many irregularities, 

 this unmistakable general advance, been subjected to no continuous 

 law of growth or variation ? Had our education been purely scien- 

 tific, or had it been sufficiently detached from influences which, how- 

 ever ennobling in another domain, have always proved hindrances 

 and delusions when introduced as factors into the domain of physics, 

 the scientific mind never could have swerved from the search for a 

 law of growth, or allowed itself to accept the antliropomorphisui 

 which regarded each successive stratum as a kind of mechanic's 

 bench for the manufacture of the new species out of all relation to 

 the old. 



Biassed, however, by their previous education, the great ma,jority 

 of naturalists invoked a special creative act to account for the ap- 

 pearance of each new group of organisms. Doubtless there were 

 numbers who were clear-headed enough to see that this was no 

 explanation at all, that in point of fact it was an attempt, by the 

 introdiiction of a greater difficulty, to account for a less. But 

 having nothing to offer in the way of explanation, they for the 

 most part held their peace. Still the thoughts of reflecting men 

 naturally and necessarily simmered round the question. De Maillet, 

 a contemporary of Newton, has been brought into notice by Prof. 

 Huxley as one who " had a notion of the modifiability of living 

 forms." In my frequent conversations with him, the late Sir Ben- 

 jamin Brodie, a man of highly philosophical mind, often drew my 

 attention to the fact that, as early as 1794, Charles Darwin's 

 grandfather was the pioneer of Charles Darwin. In 1801, and in 

 subsequent years, the celebrated Lamarck, who produced so pro- 

 found an impression on the public mind through the vigorous 

 exposition of his views by the author of ' Vestiges of Creation,' 

 endeavoured to show the development of species out of changes of 

 habit and external condition. In 1813, Dr. Wells, the founder of 

 our present theory of dew, read before the Eoyal Society a paper in 



