Throughout the whole of the journal of this long cruise, which Darwin afterwards published in an enlarged form, it is impossible not to be struck at every turn with the way in which his inquisitive mind again and again recurs to the prime elements of those great problems towards whose solution he afterwards so successfully pointed out the path. The Darwinian ideas are all already there in the germ; the embryo form of the 'Origin of Species' plays in and out on every page with the quaintest elusiveness. We are always just on the very point of catching it; and every now and again we do actually all but catch it in essence and spirit, though ever still its bodily shape persistently evades us. Questions of geographical distribution, of geological continuity, of the influence of climate, of the modifiability of instinct, of the effects of surrounding conditions, absorb the young observer's vivid interest at every step, wherever he lands. He is all unconsciously collecting notes and materials in profuse abundance for his great work; he is thinking in rough outline the new thoughts which are hereafter to revolutionise the thought of humanity. Five years are a great slice out of a man's life: those five years of ceaseless wandering by sea and land were spent by Charles Darwin in accumulating endless observations and hints for the settlement of the profound fundamental problems in which he was even then so deeply interested. The 'Beagle' sailed from England to the Cape de Verdes, and already, even before she had touched her first land, the young naturalist had observed with interest that the impalpably fine dust which fell on deck contained no less than sixty-seven distinct organic forms, two of them belonging to species peculiar to South America. In some of the dust he found particles of stone so very big that they measured 'above the thousandth of an inch square;' and after this fact, says the keen student, 'one need not be surprised at the diffusion of the far lighter and smaller sporules of cryptogamic plants.' Would Erasmus Darwin have noticed these minute points and their implications one wonders? Probably not. May we not see in the observation partly the hereditary tendencies of Josiah Wedgwood towards minute investigation and accuracy of detail, partly the influence of the scientific time-wave, and the careful training under Professor Henslow? Erasmus Darwin comes before us rather as the brilliant and ingenious amateur, his grandson Charles as the instructed and fully equipped final product of the scientific schools.