The great naturalist who was born a hundred years ago to-day, and who, though an almost lifelong sufferer from chronic illness, for more than forty years poured forth a stream of scientific works of supreme importance as well as of popular interest, is yet very imperfectly known to the present generation of readers. It is twenty-eight years since the last volume of the series appeared, and it is probable that, with the exception of his "Naturalist's Voyage Round the World," few of the readers of this notice have any first-hand knowledge of the long series of his scientific works, ten in number, without counting those on geology and descriptive natural history. Such works as "The Origin of Species," "The Descent of Man," "The Fertilisation of Orchids," "The Expression of Emotions in Man and Animals," "The Movements and Habits of Climbing Plants," and "The Formation of Mould by Earth Worms," should be read by everyone who wishes to know why Darwin is estimated so highly that the only doubt seems to be whether he should rank as among the greatest, or as the very greatest, of scientific discoverers and writers.

     This lofty place has been given to him by his contemporaries, first, on account of his great discovery of the law of natural selection; next for his thorough study, for twenty years before making it known in all its applications and far-reaching consequences; and, lastly, for the unexampled mass of facts and experiments he had accumulated, and the extreme fairness and great logical power he had devoted to its exposition and demonstration. Such an amount of carefully-examined facts and sound reasoning, characteristic of the whole series of his works, has probably never before been adduced in support of a grand and newly-discovered theory.

     Like many great and original thinkers, Darwin showed no special ability at school or college. He spent seven years at Dr. Butler's school at Shrewsbury, where the teaching was wholly classical, and he tells us that he was considered by all his masters, and by his father, as rather below the common standard in intellect. He cared nothing for the dead languages or for ancient history, but became at once interested in any natural phenomena or instruments for scientific research. His elder brother experimented in chemistry at home, and Darwin constantly helped him, and was rebuked by Dr. Butler for wasting his time on such useless subjects. He was afterwards for two years at Edinburgh University studying medicine, but here he found the lectures "intolerably dull," and the same was the case at Cambridge, where he had to work very hard to get his degree. During all this time his greatest delight was in sport, especially shooting, which he practised incessantly while at Cambridge. He also early developed a taste for collecting shells, coins, minerals, etc., as well as trying to find the names of all the plants he met with. But at Cambridge he was initiated into the pleasures of beetle-collecting, which soon became a passion, and he had the delight of finding some species new to Britain.

     His real education consisted, however, in association and conversation with a number of clever or eminent men whom he met at his home, at Edinburgh or at Cambridge; and more especially in his becoming a favourite pupil of Professor Henslow, the botanist, who taught him much geology and botany during their walks together, which were so frequent that he was known in the university as "the man who walks with Henslow." This was probably the turning-point in his life, as by the Professor's recommendation he obtained the appointment of naturalist on the "Beagle;" spent four years in the Southern hemisphere; made a reputation as a geologist and a collector, and obtained that knowledge of the distribution and inter-relations of living things which forced upon his attention the great problem of the origin of species, and gave him the determination to devote himself to its study in order, if possible, to discover the solution.

     How strange it seems to us now, that, but for the fortunate chance of a naturalist being wanted just when Darwin had passed his examination, and Professor Henslow being the person asked to recommend one, he would almost certainly have become a clergyman; in which case he would have been, no doubt, an admirable country parson, but the "Origin of Species" would not have been written, or, if something like it had been produced without the preliminary twenty years' of continuous work which Darwin devoted to it, the whole theory might have fallen into oblivion for another half-century, choked and smothered by the avalanche of scorn, bigotry and misrepresentation which would have been poured upon it, and under which, without the help of his already half-convinced friends Hooker, Lyell, and Huxley, any less adequate presentation of it would almost certainly have been overwhelmed.

     If we call to mind the great names of those who have devoted their lives to science there is only one other which can be placed on an equality with Darwin--that of the illustrious Sir Isaac Newton. And although their spheres of thought and work were so different, there was much general resemblance between them. Both possessed the qualities of high reasoning powers, of immense industry, and almost unexampled patience and modesty as regards their own discoveries. But it must be remembered that Darwin had to do more preliminary work than had Newton. By long-continued study, observation, and experiment he had to collect a vast body of facts, as did the great astronomer, Tycho Brahe; to compare and organise those facts so as to elicit some of the natural laws underlying them, as did the illustrious Kepler; and also by an inspirational flash of genius comparable with that of Newton, to discover the fundamental principle which, when applied to these vast masses of facts and phenomena, brought order out of chaos and illuminated the world of life as Newton's law illuminated the universe of matter. Not, therefore, without cause do the disciples and admirers of Darwin claim for him the highest place in the hierarchy of science.

     Darwin tells us, in his most delightful fragment of an autobiography, that it was in 1838, two years after his return home from his great voyage, that the idea of natural selection occurred to him on reading Malthus' "Principles of Population." He at once saw that it would explain some of the most curious facts he had observed during the voyage, but he also saw the necessity of collecting every possible fact bearing on the subject in order to ascertain if it would explain them all. To this enormous work he devoted himself for twenty years, studying the vast literature of horticulture and the breeding of animals, and on all points where information was deficient supplementing it by ingenious and varied experiments carried out with the greatest patience and most thorough accuracy. He had also sketched out and composed a portion of a great work upon the subject; and though often urged by his few intimate scientific friends to prepare and write a condensed account of his views, he always refused, till his hand was forced by the independent discovery of his fundamental theory; and thus the "Origin of Species" was published in 1859, after twenty-one years of preparation.

     In the case of Newton the idea of Universal Gravitation came to him in 1666 (when twenty-four years of age) as the result of witnessing the fall of an apple from the tree. Reasoning from the known laws of fallen bodies, he concluded that the earth's attraction caused them; and as all planetary bodies seemed to require some such attraction to keep them in their orbits, he reasoned out a hypothetical law applicable to all matter. Applying this law to the distance and motions of the earth and moon, as then known, he found a discrepancy of about 12 per cent., and therefore put aside his theory for a time. About five years later a new and more accurate measurement of the earth was made, and by using this he found that the discrepancy disappeared, and he became convinced of the correctness of his theory, which by 1684 he had demonstrated mathematically. It was, however, only through the solicitations of his friend, the great astronomer Halley, and of the Royal Society, that he put his whole mathematical theory into form, and the "Principia" was published in 1687, also twenty-one years after its inception.

     There is, I believe, in the whole history of science no other case than these two of a great world-embracing theory capable of modifying the whole field of scientific thought, having been for so long a period deliberately withheld from publicity in order that it might be presented with such a full array of facts and of reasoning as almost to compel acceptance by those best able to form an independent judgment. Both physicists and biologists may, therefore, perhaps agree to place Newton and Darwin side by side as the great twin-brethren of scientific discovery.