and speculative. There are many departments of natural science in which it seems a necessary condition of experimenting, that it can rarely be so conducted as to leave no room for doubt; and this inherent difficulty presses hard upon the subject of the volumes before us: but time and space fail us for so extensive an inquiry, and with this preliminary caution we must limit ourselves to such general intimations as may justify our favourable estimate of Mr. Hassall's work.

Few sections of natural science are so unpromising as this. The motley scum of the standing pool, the dark slime that makes our garden walks unsightly and our woodland path uncertain, the dregs that offend the sense in the ditch or drain, supply a large portion of its material. We take up what seems to be little else than a confused and accidental mass; and when we have so far conquered our annoyance as to venture on manipulation, we find that there is before us a distinct and marvellous organism, chiefly of fibrous structure, passing through the regular stages of growth, maturity, and reproduction, and presenting, throughout its changes, phenomena which make us halt in our conclusions, and leave us doubtful to what definition of existence we are to refer their forms and movements— whether they are the result of vegetable irritability, or of animal life. These startling appearances are illustrated at considerable length and with much distinctness by Mr. Hassall in his 'Introduction,' and in his remarks on the Characea: we cannot, however, repel the suspicion that, close and apparently complete as may be the researches of such sharp-sighted observers as Vaucher, Unger, and Varley, there is yet much to be done before we can approach the determination of so difficult and complicated a question. Details of such subtle and elusive character as those belonging to the present investigation, require the severest testing. Reiterated experiment, by men of differing views, can alone settle the question; and even after every difficulty seems to have been fairly met, and main facts satisfactorily established, it will excite no surprise in the experienced observer, if it should be found in the event, that some critical circumstance has been overlooked; that some unexpected variation interferes with the general course of movement or transition, and that the entire labour of explanation and construction has to be recommenced. We cannot think that the time has yet arrived when a decisive opinion may be safely given. In one respect Mr. Hassall seems to have failed in supplying sufficient material for determining even the present state of these complicated questions: he has not given their history; and without this; in other words, without ascertaining what has been done, and in what manner, up to the present time; without a

minute specification of the successive steps by which our knowledge has been obtained; it is impossible to gain a right apprehension of the science in its actual state : results are not enough for accurate information. Our author apologises for this defi ciency, and promises to set all right in a second edition-we fear that this may not be quite satisfactory to the purchasers of the first.

Mr. Hassall has, in one instance, advantageously allowed himself to pass over the strict geographical limits of his subject, for the purpose of illustrating a point of some historical interest, respecting which there has been, at one time or other, a good deal of uncertain and unsatisfactory speculation. So far back as 1823, the celebrated Ehrenberg had observed on the borders of the Red Sea, a singular phenomenon, which led him at once to the very obvious explanation of its distinctive name. In that year he was residing at Tor, in the immediate neighbourhood of Mount Sinai.

'On the 10th of December,' he writes, I then saw the surprising phenomenon of the blood-red colouration of all the bay which forms the port of that city. The high sea, without the boundary of the corals, preserves its ordinary colour. The short waves of a tranquil sea bring upon the banks during the heat of the day, a mucilaginous matter of a blood-red colour, and deposit it upon the sand, in such a manner as that, in the course of a good half hour, all the bay, with the receding tide, is surrounded with a red border of many feet in depth. I removed from the water some specimens, with glasses, and carried them to a tent which I had near the sea. It was easy to see that the colouration was due to little tufts, scarcely visible, often greenish, and sometimes of an intense green, but for the most part of a deep red; the water upon which they floated was always colourless. This very interesting phenomenon, sufficient to afford a reason for the etymology of the name which this sea has received, (an etymology up to the present time always buried in complete obscurity,) attracted all my attention. During many days, I observed also the colouring matter with the microscope; the tufts were formed of little bundles of filaments of an oscillatoria; they were fusiform and elongated, irregular, having rarely more than the diameter of a line, and were contained in a sort of mucilaginous sheath.'

The instance, however, was not quite satisfactory, inasmuch as the phenomenon exhibited itself on a scale somewhat too limited for general inference. But it has been more recently observed, over a breadth of surface which gave ample evidence that the singular effect witnessed and explained by Ehrenberg, was by no means confined to the shores of a secluded bay, but that it ranged over so large a portion of the Erythræan sea, as

to account entirely for its ancient designation, originally applied to a much greater marine superficies than that which is shut in by the shores of the Arabian gulf. M. Evenor Dupont, a 'distinguished advocate of the Isle of Mauritius,' on his voyage to Europe, by what is called the 'overland' passage, made it his especial business to look out for all appearances, permanent or accidental, that might afford any illustration of the distinctive term. The results of his persevering observation shall be given in his own lively and expressive language.

The 8th July last (1843), I entered into the Red Sea, by the strait of Babelmandel, upon the steam-boat the Atalanta, belonging to the Indian company. I demanded of the captain and the officers, who for a long time navigated in these latitudes (parages), what was the origin of this ancient name of the Red Sea; if it was owing, as some have pretended, to sands of that colour, or, according to others, to rocks. None of these gentlemen could reply to me; they never, they said, remarked anything to justify this denomination. I observed then for myself, as we advanced; whether the ship approached by turns the Arabian coast, or the African coast, the red was in no part apparent. The horrid mountainous barriers which border the two banks were uniformly of a blackish brown, except when in some places the appearance of an extinct volcano had left long white streams. The sands were white, the reefs of coral were white also; the sea of the most beautiful cerulean blue. I had given up the hope of discovering my etymology.

On the 15th July, the burning sun of Arabia awoke me suddenly by shining all at once from the horizon, without spot, and in all its splendour. I turned myself mechanically towards the window of the poop to seek a remnant of the fresh air of the night, before the ardour of the day had devoured it. What was my surprise, to behold the sea tinted with red as far as the eye could reach! Behind the ship, upon the deck, and on all sides I saw the same phenomenon. I interrogated the officers anew. The doctor pretended that he had already observed this fact, which was, according to him, produced by the fry of fish floating on the surface. The others said that they did not recollect having seen it before. All seemed surprised that I should attach such interest to it. If it be necessary to describe the appearance of the sea, I should say, that its surface was covered with a compact stratum, of but little thickness, but of a fine texture, of a brick red, slightly tinged with rouge; sawdust of this colour of mahogany, for example-would produce very nearly the same effect. It seemed to me, and I said at the time, that it was a marine plant. No one seemed of my opinion; so, with a pail tied at the end of a rope, I was able to gather, with one of the sailors, a certain quantity of the substance; this, with a spoon, I introduced into a white glass bottle, thinking that it would be the better preserved. The next day the substance had become of a deep violet,

and the water had taken a pretty pink tinge. Fearing that the immersion would hasten the decomposition instead of preventing it, I emptied the contents of the bottle upon a piece of cotton (the same which I remitted to you). The water passed through it, and the substance adhered to the tissue. In drying, it became green, as you actually saw it. I ought to add, that on the 15th July, we were by the side of the town of Cosseir; that the sea was red the whole day; that the next, the 16th, it was the same until near mid-day, the bour at which we found ourselves before Tor, a little Arabian village, the palms of which we perceived in an oasis on the border of the sea, below the chains of mountain which descend from Sinai, even to the sandy shore.'

We avail ourselves of the present opportunity to give a brief but emphatic recommendation of Dr. Harvey's Phycologia. It is at once scientific and artistic; we cannot recollect that we have at any time inspected a work of more perfect execution. Dr. Greville's volume, independently of its incompleteness, is a work of science rather than art; Dr. Harvey's is both. The first number is exquisite; and if we seem to detect a little less handiwork, and somewhat inferior delicacy of texture in the later plates, we are glad to recollect that we have been made fastidious by the earlier examples, and to believe that such scrupulous elaboration has been rendered impracticable by an increasing and urgent demand.

Art. V.-History of the Eighteenth Century, and of the Nineteenth, till the overthrow of the French Empire. With particular reference to Mental Cultivation and Progress. By F. C. Schlosser, Privy Councillor and professor of history in the University of Heidelberg. Translated, with a Preface and Notes, by D. Davison, M.A. Two vols London: 1843-4.

PROFESSOR Schlosser enjoys a European reputation, and his history, we are told, has excited great attention on the Continent. It has already appeared in a French and Dutch translation. The author exhibits throughout a deep and intimate acquaintance with his subject, unfolds many new views, and draws his general conclusions, in a manner indicative of a man of sense and true philosopher. The theme is certainly an interesting one. Scarcely any period in the history of the world affords such scope for deep contemplation as the eighteenth century. It was emphatically an age of transition,

'sometimes gradual and peaceful, and sometimes rapid and revolutionary, from the still lingering usages and institutions of the middle ages, to the full light and liberty of the present day. The progress is continuous in our own century, notwithstanding occasional drawbacks, pointing onward to a period of still freer institutions, of greatly increased knowledge, of higher degrees of mental refinement and moral culture.'

This work may be looked upon as the more useful and important, inasmuch as the author stands aloof from the two great parties which almost share between them, the literary world in Germany. Hence his opinions are likely to be the more straightforward, and uttered with the greater freedom. He treats literature, for the most part, only as it bears upon life and morals, and the English more incidentally (though, by the bye, sometimes a little too severely, we think,) than the French and German. With regard to the choice of authors for discussion, he pursues a plan which we shall endeavour to imitate, only on a much smaller scale, in the few pages to which we are limited-He selects such authors only as at once indicated a great change in the modes of thought and morals of the people, and exercised an important influence in promoting and confirming that change. His great object, we are informed, and as we soon discover, is to draw a true picture of the moral and social condition of the age, and to show in what respects and through what intrumentality the men and the literature of one country, acted upon and affected those of another. As respects his treatment of English literature, the novelty and interest consist, especially in the new results which are deduced, in the new connections which are pointed out, and in the manner in which the literature of England is shown to have been derived from that of France, and the effect, which, in its turn, it produced both in France and in Germany,-effects which are still, not only visible, but which characterise the whole prevailing literature of Europe.'

The attentive student of history will not have failed to observe that as there are two essentially distinct classes of the human family, when considered with reference to the question of civilization, so there will necessarily be a real difference between the history of nations, which may be said to be stationary, and that of those which are progressive, that is, between the history of the oriental nations, such as China, Japan, India, ancient Egypt, Persia, and the early times of the Greeks and Romans, and that of the Western States, coming under the denomination of modern history. Of course these two different species of history, require a different method of treatment. At first view, it might be thought that the middle ages, inas