Page:Popular Science Monthly Volume 15.djvu/433

Rh , at all resembling those existing on the earth should exist on other planets or in other solar systems. It is conceivable that very low forms of vegetable life may exist on other planets and may have been by some means transported to the earth; the idea is conceivable, though highly improbable. But it is quite impossible that that infinitely complex series of circumstances which on the earth has conspired to produce from the lowest living forms a crustacean, for example, should have occurred elsewhere; still less is it possible that a bird or a mammal should exist elsewhere; still more impossible, again, that there should be elsewhere a monkey or a man.

With regard to any future scientific expeditions, it would, however, be well to bear in mind that the deep sea, its physical features and its fauna, will remain for an indefinite period in the condition in which they now exist and as they have existed for ages past, with little or no change, to be investigated at leisure at any future time. On the surface of the earth, however, animals and plants and races of men are perishing rapidly day by day, and will soon be, like the dodo, things of the past. The history of these things once gone can never be recovered, but must remain for ever a gap in the knowledge of mankind.

The loss will be most deeply felt in the province of anthropology, a science which is of higher importance to us than any other, as treating of the developmental history of our own species. The languages of Polynesia are being rapidly destroyed or mutilated, and the opportunity of obtaining accurate information concerning these and the native habits of culture will soon have passed away.

work was left unfinished by the author at his death last year, and it has been edited and prepared for the press, as is understood, by Mrs. Lewes, who prefixes to the volume this brief note: "The following problem is published separately, in obedience to an implied wish of the author, and has been printed from his manuscript with no other alterations than such as it is felt certain that he would have sanctioned. Another volume will appear in the autumn."

Like all of Mr. Lewes's philosophical writings, this book is worthy the attention of those interested in the subjects he discusses, for he had an acute and fertile mind, wayward if not independent, and by no means wanting in originality. But he was too versatile for preëminence. A man can not be great in all things, nor really great in anything if he dabbles in everything. Mr. Lewes was novelist, dramatist, linguist, critic, editor, physiologist, historian of philosophy, and psychologist. Much of his work was poor, much middling, and some of it excellent, but he left no impression upon any one subject such as he might have made by concentrating his powers upon it with an exclusive devotion. He was a brilliant talker, and an admirable story-teller; was sought by society, and was fond of of it, all his striking and varied acquisitions coming readily into play in cultivated social circles. In the latter portions of his life he was more secluded, and gave himself more closely to a restricted line of serious study which resulted in the publication of his maturest work, "The Problems of Life and Mind," of which the present volume is the last issued. He will probably be longest known by his "History of Philosophy," but in the present transition state of biological and psychological theory these latter works will be found well worth consulting. The volume now issued is expository and controversial with regard to various important psychological questions, but propounds little that is new, the author being content to reargue more fully various positions that he has heretofore assumed. It has undoubtedly been improved in style by passing through the editorial hands of Mrs. Lewes.

is careful to employ the term "sewer-air" instead of "sewer-gas," inasmuch as the latter phrase gives rise to the erroneous idea that in sewers there exists a distinct gaseous substance possessed of marked distinguishing characteristics; whereas the fact is, that the gas or air of sewers is a continually varying mixture of the gases which makeup the atmosphere, blended with a relatively small proportion of certain other gases formed by the decomposition of the sewage, together with aqueous vapor and vapor of organic compounds. The noxious substances in sewer-air would appear to be either minute solid particles or else particles of vapor, and not gaseous.