from a search in unpublished Portuguese documents, relating to the geography of the eastern coast of Africa, he thinks himself able to prove that the region assigned to the diminutive Doko' is really inhabited by the tall, muscular, and powerful Shankalli negro." The French traveller, M. d'Abbaadie, discovers in this race the Doko themselves. The name Doko he conceives to be a general designation of the slave country, or of a country imperfectly known. The dwarfs, whose existence he does not deny, he supposes to be the Gonga people. Upon this subject Mr. Johnston intimates his possession of some important evidence. The Doko of Harris he explains to be a tribe of monkeys, to which, however, he is willing to allow an unusual portion of instinctive cleverness, and therefore of capacity for domestication; and his belief is strengthened "from the fact that the ancient Egyptians did call to their aid such a species of animal servants; and in many of the representations of the habits and arts of that people, monkeys are employed upon the duties they are so well adapted for that of collecting fruits for their masters."

Of the Gongas, Mr. Johnston offers some illustrations. Occupying, in remote ages, the whole table-land of Abyssinia, they endeavoured, by all means in their power, to exclude the intercourse of strangers; and their geographical position favoured the design. They appear in ancient history under various names. Their commerce was almost entirely confined to the exchange of gold for salt; and their transactions with the trading caravans were conducted without the intervention of language. Johnston confirms the conjecture of Heeren, which identifies the altar, or table of the sun, of the Ethiopians, mentioned by Herodotus, with the market-place, "in which, at a later day, the trade with the strangers was transacted." The members of the Gonga nation, whom he had an opportunity of observing, were Zingéro and Kuffah slaves. They are small in stature, not exceeding five feet four inches, "delicately made, and of a pale yellow complexion;" the aperture of the eyelid being in some of them straight-in others obliquely divided. "Their hair was straight and strong; a triangular formed face, the forehead being low and long, and the chin very pointed." The recognition of many corresponding customs between the Gongas and the Hottentots of the Cape impressed Mr. Johnston with the conviction that they ought to be referred to the same family. Of this remarkable people in northern Abyssinia, the Adjows and the Falasha are the remains an investigation of whose manners and customs is recommended to future travellers in that portion of the mysterious wildernesses of Africa.

Our readers will perceive, from these analytical specimens of

Mr. Johnston's travels, that they contain much information, both new and important, respecting that mysterious country which is now attracting the earnest gaze of the philosopher and the Christian, not less than of the politician and the merchant. If the view afforded by Johnston be less extensive than that given by Harris, it is certainly more minute. His pictures of the domestic manners of the Abyssinians possess a decided value. His style, without being elegant, or indeed correct, is always simple and unaffected. The occasional indications of religious opinion might have been withheld with advantage; and we mention, only to condemn, the attempt to explain one of the most miraculous interpositions of Divine Providence in the history of the ancient Hebrew people. With these qualifications, we recommend these "Travels" to all who feel a sympathy with ignorance, beginning, we trust, to emerge from its long night of delusion and guilt.

ART. VIII.-Geology; Introductory, Descriptive, and Practical. By DAVID THOMAS ANSTED, M.A., F.R.S.; Fellow of Jesus College, Cambridge; Professor of Geology in King's College, London. Two vols. 8vo. London: Van Voorst.

1844,

THE important station which Professor Ansted occupies, and the reputation which he has obtained in fulfilling its duties, led us to expect a good book at his hands; but the work before us has exceeded our expectations, being by far the best suited to the real wants of the age of any work on geology, that has yet appeared: these wants have been understood by one who is fully competent to supply them, and who has done so in a very pleasant, and therefore a very acceptable manner. Men who write for the information of others, to do it properly, should put themselves into the position of those others, and enquire what, in such a case, they themselves would desire-what kind of information, and in what manner imparted? Books ought not to be written in order to parade the superior attainments of the writer, but solely to convey information in the best possible way. When the professors of a science meet together to hear papers read, these may be as dry and technical as they please; they may be all the better for being only such as those who understand the science will enjoy. And if these papers are published as transactions, well and good; still they are still only in the form of books calculated for those who are adepts in the science. But to make books, for general reading, technical, as the transactions of a society, shows want of tact: and to make a show of condescending to popular ignorance is worse

-is, in fact, the impertinence of a coxcomb and shows an utter disqualification for instructing others; for it evinces a want of the first requisite for writing intelligibly.

Professor Ansted well knows the kind of information that men need in the present age, which is such information as men of taste and refinement require: not to make gentlemen become miners and coalheavers, but that gentlemen may obtain that scientific information which will enable them to bring the resources of science to the aid of our labouring population, increasing the products of industry thereby; while, at the same time, a science like geology furnishes an occupation to the mind, second only to astronomy in grandeur and importance; and even more interesting, in one sense, than the study of the heavenly motions, as making us acquainted with our present home-as concerning the knowledge of that place which is, during life, the all in all to man.

It has passed into a sort of bye-word, that the most important part of a lady's letter is to be found in the postscript. We think that it applies to books also; for we have often found that the most important chapter of a book, for letting us into the mind of the author, has been the concluding chapter. This has brought us into the habit of reading the last chapter first, that we may know what the author has done, and not hastily accuse him of neglecting that which he never intended to do: or we suspend our judgment concerning the success with which an author has accomplished his first intentions, until we have compared the introduction with the conclusion of the work; and thus know fully what his intentions were, and how far he has realized them to his own satisfaction. In the concluding chapter of Professor Ansted's work, he thus expresses himself:

"The nature of geology-an account, that is, of the materials of which the earth's crust is made up; of the order in which those materials are arranged; of the changes in the original arrangement produced by subsequent mechanical violence; of the organic bodies found associated with the inorganic materials; and lastly, of the practical benefit that is to be derived from knowing something of these facts; all this has now been stated in as simple and clear a manner as my ability and knowledge of the subject have permitted. It has been my object throughout the entire work to set before the reader, in their proper light, these various matters; and I have carefully avoided introducing such disputed points as were likely to create confusion, or require that he should afterwards have to unlearn anything that is here taught."(p. 532).

We highly approve of this: it has our most hearty concurrence. In what is proposed to be done, and what he abstained

from doing, Professor Ansted has exactly chalked out the course which every discreet geologist ought to pursue, in the present state of our knowledge; and the very words in which it is expressed seem to us remarkably well chosen-to every one of them we cordially assent. Professor Ansted continues :→→

"But, although the subjects of discussion have been hitherto thus limited, it is not right that I should conclude without informing the geological student that there is such a science as physical geology, and that many of those persons to whose investigations the most important discoveries in descriptive geology are due, have also exercised themselves in endeavouring to reduce to a system the observations that have been made, and discover, if possible, the nature and mode of operation of the laws according to which the earth has, after countless ages, assumed its present condition. But the theories of geology have not yet been thoroughly confirmed by experiment; nor can this be a matter of surprise when we consider how recent is the date of many of those observations, without including an explanation of which no one should venture to propound a theoretical speculation. It has seemed, therefore, to me more prudent to avoid all allusion to such theories, than to mention them only to point out their imperfections, and thus perhaps add to the difficulties with which the subject is surrounded.......I have endeavoured throughout the present work to confine myself to the explanation of phenomena, and the elucidation of laws of the first degree of generality; those of greater generality, the theories of geology properly so called, not being perfectly elaborated; and the analysis of phenomena, the immediate object of such theories, not having been yet fully effected." (p. 534).

We can admire the delicate and gentlemanly feelings which dictated the above-the unwillingness to differ from his friends in anything the reluctance at seeming only to go a certain length with them. But we have no doubt that ultimately it will be found that the cautious course is the only right road, as, in the present state of our knowledge, it is the only path which is either wise or safe. Had all geologists conducted their investigations in the same patient and truly philosophic spirit, we should have been spared many of the painful and insulting things which, as men and Christians, it has been our misfortune to hear and read. There is nothing of this distressing character in the work of Professor Ansted-nothing contrary to the good taste, as well as good feeling, of respecting both himself and his readers. There is a dignity of this kind in all the productions of well-stored and well-cultivated minds, which we have found so invariably, that we have come to the conclusion that it is a necessary concomitant of minds of the first order, and that they are inseparable the one from the other.

There is nothing blameable in the mere act of forming an

hypothesis, or framing a system to account for and classify unusual phenomena. On the contrary, we think it indispensable for accurate investigation, and for giving any new facts their true place among the sciences, that we should form some general notions in our own minds of the way in which these discoveries may be ranged under those principles or general laws with which we are already acquainted. If it be merely in order to keep analogous facts together, some classification is necessary; for it is only by systematic arrangement, and the comparison out of which it springs, that we arrive at clearness. Systems only become dangerous when, having founded them on insufficient facts, we refuse to abandon them when new and contrary facts appear; but, in perverseness of spirit, endeavour to wrest those facts to bring them within our hypothesis. And they become still more dangerous and reprehensible when, from insufficient facts of one kind, we draw inferences against conclusions of another kind, which rest on a totally different basis, and depend upon an entirely different chain of reasoning, and of which the mere geologist is not more competent to form an opinion, than a mere monk of the dark ages would be to express an opinion concerning modern geology. We quite agree with Professor Ansted, in thinking that we have not yet a sufficient number of facts before us to construct any durable systemany theory in which there will not, of course, be much to learn." We will, therefore, follow the example set us by Professor Ansted, and, waiving such topics at the present time, proceed with the pleasing duty of giving some account of the work now before us.

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The work, as its title imports, is divided into three partsintroductory, descriptive, and practical geology. The first part, consisting of four chapters, occupying eighty pages, lays out very clearly the foundations on which geology, as a science, may be understood to rest, pointing to effects which we know to be produced by causes now in action, as explaining geological phenomena which appear so very similar to these effects, that they may fairly be ascribed to similar causes. And the various technical expressions are explained, so as to enable the reader to understand what is meant by stratification, and the structural phenomena of rocks, and everything else which relates to these large masses and these grand distinctions-the only distinctions which can be taken into account by those who prepare geological maps and sections. The remaining chapters of the introduction treat of the contents of these strata, as indicating, by the difference between one stratum and another, the order in which they were formed, and the interval of time