This is probably the best of Mr. Trollope's numerous works. It is by no means different in kind from its predecessors; for it stands in the path struck out by "The Warden" ten years ago. But it is better, inasmuch as it is later; that is, it is by ten years better than "The Warden," and by four years better than "Framley Parsonage." Mr. Trollope's course has been very even,—too even, almost, to be called brilliant; for success has become almost monotonous with him. His first novel was a triumph, after its kind; and a list of his subsequent works would be but a record of repeated triumphs. He has closely adhered to the method which he found so serviceable at first; and although it is not for the general critic to say whether he has felt temptations to turn aside, we may be sure, in view of his unbroken popularity, that he has either been very happy or very wise. His works, as they stand, are probably the exact measure of his strength.

We do not mean that he has exhausted his strength. It seems to be the prime quality of such a genius as Mr. Trollope's that it is exempt from accident,—that it accumulates, rather than loses force with age. Mr. Trollope's work is simple observation. He is secure, therefore, as long as he retains this faculty. And his observation is the more efficient that it is hampered by no concomitant purpose, rooted to no underlying beliefs or desires. It is firmly anchored, but above-ground. We have often heard Mr. Trollope compared with Thackeray,—but never without resenting the comparison. In no point are they more dissimilar than in the above. Thackeray is a moralist, a satirist; he tells his story for its lesson: whereas Mr. Trollope tells his story wholly for its own sake. Thackeray is almost as much a preacher as he is a novelist; while Mr. Trollope is the latter simply. Both writers are humorists, which seems to be the inevitable mood of all shrewd observers; and both incline to what is called quiet humor. But we know that there are many kinds of laughter. Think of the different kinds of humorists we find in Shakspeare's comedies. Mr. Trollope's merriment is evoked wholly by the actual presence of an oddity; and Thackeray's, although it be, by the way, abundantly sympathetic with superficial comedy, by its existence, by its history, by some shadow it casts. Of course all humorists have an immense common fund. When Cradell, in the present tale, talks about Mrs. Lupex's fine torso, we are reminded both of Thackeray and Dickens. But when the Squire, coming down to the Small House to discuss his niece's marriage, just avoids a quarrel with his sister about the propriety of early fires, we acknowledge, that, as it stands, the trait belongs to Trollope alone. Dickens would have eschewed it, and Thackeray would have expanded it. The same remark applies to their pathos. With Trollope we weep, if it so happen we can, for a given shame or wrong. Our sympathy in the work before us is for the jilted Lily Dale, our indignation for her false lover. But our compassion for Amelia Osborne and Colonel Newcome goes to the whole race of the oppressed.

Mr. Trollope's greatest value we take to be that he is so purely a novelist. The chief requisite for writing a novel in the present age seems to be that the writer should be everything else. It implies that the story-telling gift is very well in its way, but that the inner substance of a tale must repose on some direct professional experience. This fashion is of very recent date. Formerly the novelist had no personality; he was a simple chronicler; his accidental stand-point was as impertinent as the painter's attitude before his canvas. But now the main question lies in the pose, not of the model, but of the artist. It will fare ill with the second-rate writer of fiction, unless he can give conclusive proof that he is well qualified in certain practical functions. And the public is very vigilant on this point. It has become wonderfully acute in discriminating true and false lore. The critic's office is gradually reduced to a search for inaccuracies. We do not stop to weigh these truths; we merely indicate them. But we confess, that, if Mr. Trollope is somewhat dear to us, it is because they are not true of him. The central purpose of a work of fiction is assuredly the portrayal of human passions. To this principle Mr. Trollope steadfastly adheres,—how consciously, how wilfully, we know not,—but with a constancy which is almost a proof of conviction, and a degree of success which lends great force to his example. The interest of the work before us is emphatically a moral interest: it is a story of feeling, the narrative of certain feelings.

Mr. Troliope's tales give us a very sound sense of their reality. It may seem paradoxical to attribute this to the narrowness of the author's imagination; but we cannot help doing so. On reflection, we shall see that it is not so much persons as events that Mr. Trollope aims at depicting, not so much characters as scenes. His pictures are real, on the whole. Their reality, we take it, is owing to the happy balance of the writer's judgment and his invention. Had his invention been a little more tinged with fancy, it is probable that he would have known certain temptations of which he appears to be ignorant. Even should he have successfully resisted them, the struggle, the contest, the necessity of choice would have robbed his manner of that easy self-sufficiency which is one of its greatest charms. Had he succumbed, he would often have fallen away from sober fidelity to Nature. As the matter stands, his great felicity is that he never goes beyond his depth,—and this, not so much from fear, as from ignorance. His insight is anything but profound. He has no suspicion of deeper waters. Through the whole course of the present story, he never attempts to fathom Crosbie's feelings, to retrace his motives, to refine upon his character. Mr. Trollope has learned much in what is called the realist school; but he has not taken lessons in psychology. Even while looking into Crosbie's heart, we never lose sight of Courcy Castle, of his Club, of his London life; we cross the threshold of his inner being, we knock at the door of his soul, but we remain within call of Lily Dale and the Lady Alexandrina. We never see Crosbie the man, but always Crosbie the gentleman, the Government clerk. We feel at times as if we had a right to know him better,—to know him at least as well as he knew himself. It is significant of Mr. Trollope's temperament—a temperament, as it seems to us, eminently English—that he can have told such a story with so little preoccupation with certain spiritual questions. It is evident that this spiritual reticence, if we may so term it, is not a parti pris; for no fixed principle, save perhaps the one hinted at above, is apparent in the book. It belongs to a species of single-sightedness, by which Mr. Trollope, in common with his countrymen, is largely characterized,—an indifference to secondary considerations, an abstinence from sidelong glances. It is akin to an intense literalness of perception, of which we might find an example on every page Mr. Trollope has written. He is conscious of seeing the surface of things so clearly, perhaps, that he deems himself exempt from all profounder obligations. To describe accurately what he sees is a point of conscience with him. In these matters an omission is almost a crime. We remember an instance somewhat to the purpose. After describing Mrs. Dale's tea-party at length, in the beginning of the book, he wanders off with Crosbie and his sweetheart on a moonlight-stroll, and so interests us in the feelings of the young couple, and in Crosbie's plans and promises for the future, (which we begin faintly to foresee,) that we have forgotten all about the party. And, indeed, how could the story of the party end better than by gently passing out of the reader's mind, superseded by a stronger interest, to which it is merely accessory? But such is not the author's view of the case. Dropping Crosbie, Lilian, and the more serious objects of our recent concern, he begins a new line and ends his chapter thus:—"After that they all went to bed." It recalls the manner of "Harry and Lucy," friends of our childhood.

But to return to our starting-point,—in "The Small House at Allington" Mr. Trollope has outdone his previous efforts. He has used his best gifts in unwonted fulness. Never before has he described young ladies and the loves of young ladies in so charming and so natural a fashion. Never before has he reproduced so faithfully—to say no more—certain phases of the life and conversation of the youth of the other sex. Never before has he caught so accurately the speech of our daily feelings, plots, and passions. He has a habit of writing which is almost a style; its principal charm is a certain tendency to quaintness; its principal defect is an excess of words. But we suspect this manner makes easy writing; in Mr. Trollope's books it certainly makes very easy reading.

A Class-Book of Chemistry; in which the Latest Facts and Principles of the Science are explained and applied to the Arts of Life and the Phenomena of Nature. A New Edition, entirely rewritten. By EDWARD L. YOUMANS, M.D. New York: D. Appleton & Co.

Though Science has been often vaguely supposed to be something generally distinct from ordinary knowledge, yet the slightest consideration will suffice to show us that this is not the case. Scientific knowledge is only a highly developed form of the common information of ordinary minds. The specific attribute by which it is distinguished from the latter is quantitative prevision. Mere prevision is not peculiar to science. When the school-boy throws a stone into the air, he can predict its fall as certainly as the astronomer can predict the recurrence of an eclipse; but his prevision, though certain, is rude and indefinite: though he can foretell the kind of effect which will follow the given mechanical impulse, yet the quantity of effect—the height to which the stone will ascend, and the rapidity with which it will fall—is something utterly beyond his ken. The servant-girl has no need of chemistry to teach her, that, when the match is applied, the fire will burn and smoke ascend the chimney; but she is far from being able to predict the proportional weights of oxygen and carbon which will unite, the volume of the gases which are to be given off, or the intensity of the radiation which is to warm the room: her prevision is qualitative, not quantitative, in its character. But when Galileo discovers the increment of the velocity of falling bodies, and when Dalton and De Morveau discover the exact proportions in which chemical union takes place, it is evident that knowledge has advanced from a rudely qualitative to an accurately quantitative stage; and it does not admit of dispute that the progress of science is thus a progress from the indefinite to the definite.

From the point of view here taken it would appear that during the present century no science has made such rapid and unprecedented strides as Chemistry; and its progress becomes all the more striking, when we consider the state of the science previous to the French Revolution. For centuries nothing had been done in it whatever. Besides the commonest previsions of every-day life, the ancients knew scarcely anything either of chemistry or physics, except that amber possessed attractive properties. The discovery of the strong acids by the Arabs Giafar and Rhazes, and of phosphorus by Bechil, are almost the only landmarks in the history of the science, until the discovery of oxygen and the destruction of the phlogistic theory by Priestley and Lavoisier, together with the introduction of the balance and the thermometer into the laboratory, rendered quantitative experiments possible. Since then its progress has been unexampled. The law of definite proportions, not long since disputed or unwillingly accepted, has been proved to hold even among organic compounds. A nomenclature has been invented and perfected, such as no other science can boast of, whether we consider the extent to which it facilitates practical operations, or its logical value as a means of mental discipline. Chemistry has also interacted with the different branches of physics, giving us the voltaic battery, the telegraph, and the wonderful results of spectrum-analysis. On the other hand, it has analyzed the proximate constituents of animal and vegetal structures, and has even gone far toward determining some of the conditions of organic existence; while every one of the arts, whether æsthetic, therapeutic, or industrial, has received from it many and important suggestions.

In a science which advances so rapidly there is great need of popular books which shall clearly and succinctly present the very latest results of investigation, without burdening the reader with technical details. For some time there has been no such work in this country. To ascertain the newest discoveries, it has been necessary to consult the journals and memoirs of learned societies, the excellent works of Professor Miller being too cumbrous to be of much service either to the unscientific reader or to the general scholar. On the other hand, the text-books in common use have been positively detestable. The information furnished by many of them is worse than ignorance. We are tired of works on chemical physics which discourse of "calorie" and "the electric fluid,"—of works on organic chemistry which ascribe the phenomena of life to "a vital principle which overrides chemical laws." A book at once clear, concise, and modern has long been the great desideratum.

This need is most amply supplied by the recent work of Dr. Youmans. Laying no claim to the character of an exposition of original discoveries, and thus keeping aloof from involved discussion, it is at the same time so lucid in its statements, so pertinent in its illustrations, and so philosophic in its reflections, as to invest with a new charm every subject of which it treats. The author deserves high praise for taking into account the circumstance that the reading public is not entirely composed of physicists and chemists. It has been too much the fashion for writers on scientific subjects to give definitions which can be rendered intelligible only by an intimate acquaintance with the very matters defined. It would be tedious to enumerate the countless absurd explanations given in elementary text-books of the phenomena of interference, polarization, and double refraction,—explanations as enigmatical as the inscriptions at Memphis and Karnak,—explanations useless to the optician because needless, and to the student because obscure. It would seem that subjects so simple and beautiful as these could not be rendered difficult of comprehension, except by the most awkward treatment; and yet we know of no work previous to that of Dr. Youmans which does not utterly fail to give the general scientific reader any idea whatever of their nature and theory. Here, however, they are explained with clearness and elegance, and their bearing on the undulatory theory of light is distinctly shown. As other instances of most admirable exposition, we may call attention to the paragraphs on crystallization, on the atomic theory, on isomerism and allotropism, on diamagnetism, magnetic induction, and electric "currents," on the sources of heat, on the chemical and thermal spectra, on the correlation and equivalence of the forces, on the theory of ozone, on the exceptional expansion of water and the supposed complexity of its atom, on the structure of flame, on the constitution of salts, on the colloid condition of matter, on types and compound radicles, on the dynamics of vegetable growth and the production of animal power, and, above all, to the passage which describes the phenomena of latent heat. Throughout, in treating of these subjects, the author's felicity of exposition never fails him. The most difficult phenomena are rendered perfectly easy of comprehension, and their mutual relations are not left out of account. Each set of facts is treated, not as forming an isolated body of truth, but as an integral portion of the complex and logically indivisible universe. In this respect Dr. Youmans's work is far superior to the recent production of Dr. Hooker, in which, for example, the mere existence of such a doctrine as that of the correlation of forces is grudgingly noticed, and its ultimate significance entirely overlooked.