influence popular thought and colour literature. It is obvious that there are certain departments of science which from their very nature can have little or no direct influence. The mathematical researches of men like Sir William Rowan Hamilton are far too technical, too difficult and too abstruse for popular apprehension. They remain a mere name, and not even their general import is understood. The same remark applies to the mathematical work of Augustus de Morgan, who, by the way, gave valuable hints for Hamilton's great work on quaternions. But De Morgan was a logician as well, and the author of the _Budget of Paradoxes_ is worthy of remembrance in literature. In physics the case is somewhat different. The processes by which physicists like Joule and Faraday attain their results remain mysterious, but the general character of the results becomes known, their great importance is obvious, and they generate a confidence in the powers of man which in the present day goes far towards counteracting tendencies to pessimism. There are however certain sciences whose influence upon life and thought is direct, because their results bear upon man's own position in the universe. Astronomy, through its relation to the Mosaic cosmogony, belongs to this class; but its force had been felt long before the opening of the period. It is especially the sciences of geology and biology that have changed men's minds, and it is they that have produced the most books which, apart from the scientific value of their contents, might claim to rank as literature. Geology was at the opening of the period practically a new science. What had previously been done in it was trifling compared with what has been accomplished since, and its bearing upon questions of universal interest was not even suspected by the multitude. Darwin in his brief autobiography relates an anecdote illustrative of the primitive state of the science in his youth. 'I,' says he, 'though now only sixty-seven years old, heard the Professor [of Geology in Edinburgh], in a field lecture at Salisbury Crags, discoursing on a trap-dyke, with amygdaloidal margins and the strata indurated on each side, with volcanic rocks all around us, say that it was a fissure filled with sediment from above, adding with a sneer that there were men who maintained that it had been injected from beneath in a molten condition.' Even more striking than any aberration of an individual is the general fact that the prevailing theory at that time in geology was the 'catastrophic,' and a science with an unlimited command of catastrophes is no more scientific in spirit than a theology with an unlimited command of miracles. [Sidenote: Sir Charles Lyell (1797-1875).]