ON COAL. 121 



There are in the history of science two eras which, more than all 

 others, strike the imagination and fill the mind with admiration. Or 

 rather, I should say, two moments, the greatest in the intellectual 

 h'story of the human race. They are those in w^hich were horn in 

 the mind of man the fundamental ideas of astronomy and geology — 

 the ideas of infinite space and infinite time, containing other worlds 

 and other creations. You have all, probably, thought of the sublimity 

 of that moment when the idea of infinite space, peopled with worlds 

 like our own, was first thoroughly realized by the mind of man. You 

 have all, probably, shared in imagination the exstacy of Galileo as 

 gazing with awe through the first telescope, the phases of Venus and 

 the satellites of Jupiter suddenly revealed to him the existence of 

 other worlds besides his own. Before that pregnant moment our own 

 was alone in the universe. Sun, moon, and stars were but satellites 

 to the earth. Astronomy was but the geometry of the heavens ; the 

 geometry ot the curious lines which these ^'' luandering fires" traced 

 upon the crystalline concave of the skies. In an instant the great 

 fundamental idea of modern astronomy was born in the mind of 

 Galileo. In an instant man's intellectual vision is infinitely extended, 

 but his own world, before so great, has shrunk into an atom in the 

 midst of infinite space ; has become a younger sister, a comparatively 

 insignificant member in a great family of worlds. 



We have all been accustomed to look upon this as the grandest 

 moment in the intellectual history of man. But there is another 

 moment less known, or if known^ less thought of, because less under- 

 stood and less appreciated^ but not less grand. It is that in which 

 was born in the mind of man the fundamental idea of geology ; in 

 which the idea of other time-worlds besides our own entered the mind 

 of the aged Bufi'on. 



For many years, indeed centuries, it had been observed that organic 

 remains, particularly marine shells, might be found far inland, and 

 even high up the slopes of mountains. There was much speculation 

 among scientific men as to the origin of these shells. They were 

 attributed by some to the deluge, by others more truly to gradual and 

 permanent changes in the relative level of sea and laud. But no one 

 for a moment supposed that they belonged to any period anterior to 

 the present epoch. Some may have supposed that they were extending 

 the known limits of the present epoch, that they were discovering new 

 continents in the ocean of time, but never dreamed that these were 

 the evidences of a neiu icorld in the infinite abyss of time. Buftbn 

 himself had taken active part in these discussions. Finally, near the 

 end of the last century, and in the evening of his great and long life, 

 a large number of these remains, both marine shells and mammalian 

 vertebrates, larger than he had ever examined before, were placed at 

 his disposal and subject to his inspection. To his astonishment he 

 found them entirely different from species now inhabiting the earth. 

 In that moment, in the mind of the venerable Buffon, suddenly, like 

 Minerva from the head of Jove, was born the idea of infinite time 

 containing successive creations. In an instant man's intellectual 

 vision was again infinitely extended ; but his own world again 

 dwindled into a single day in the geological history of the earth. 



