very great detriment, although they publicly acknowledged his zealous and economical services,' and 'acquitted him, collec'tively and individually, of all blame.' Economical, in truth, they might well be called, even if he had saved no money to his employers by regulating the expenditure of their other servants. For we find by the statement of his expenses, that the whole charge he makes for his own, his son's, and two other gentlemen's voyage, and journey, and residence, all over the vast route through which we have followed them, during nineteen months, did not exceed one thousand pounds.

ART. XI.-1. Natural Theology, or Evidences of the Existing Attributes of the Deity, collected from the Appearances of Nature. By WILLIAM PALEY, D.D. Illustrated by a series of Plates and Explanatory Notes. By JAMES PAXTON, Member of the Royal College of Surgeons, London. 2 vols. 8vo. pp. 523. Oxford. Vincent. 1826.

2. Animal Mechanics, or the Design Exhibited in the Mechanism of the Bones, Muscles, and Joints of Animals, from the Library of Useful Knowledge, published under the Superintendence of the Society for the Diffusion of Useful Knowledge. 8vo. pp. 32. Baldwin. London. 1827.

AQUARTER of a century has elapsed since the publication of Dr Paley's admirable work, in which he applied the learning of Ray and Derham to a far more argumentative use, than they had been equal to, and brought their physical statements down to the present improved condition of our natural knowledge. We gave an account of this useful work in the Second Number of this Journal; and, of course, it is no part of our present purpose to say anything further of the original work. But it seems singular that a work so popular as the author's great name, and its own real merits, made it from the day of its publication, should not, until now, have received the aid and ornament of those illustrations which, with so little trouble, and so moderate a portion of learning, might, at any time, have been bestowed upon it, and which the nature of the subject in many places required. Dr Paley, as is well known, relies entirely upon the attention and fancy of his reader to follow him in his descriptions, both of structure and functions. When a complicated contrivance, therefore, in animal and vegetable nature is to be unfolded, there is frequently some difficulty in keep

ing steadily before the mind's eye the picture which his unassisted language, how plain and graphic soever, presents. Readers unacquainted with the sciences are, above all, apt to be embarrassed by this; and even those who are generally possessed of the requisite information, unless they happen to recollect the form of the thing described, from having actually seen it represented before, cannot attain so clear and precise a notion of it, as if they had it pictured before them. Now all this could be remedied with great ease, by a few drawings, and some notes referring to them. Mr Paxton has first thought of supplying the desideratum, and he has executed the task, in a manner so satisfactory, as well deserves the thanks of the public. So much of the subject belongs to anatomy and physiology, that it was plainly desirable that it should be done by a surgeon; and, if the difficulty of finding one disposed so to occupy himself was considerable, the obligation he has laid us under is proportionably great.

Mr Paxton very properly begins with the outset of Paley's argument, where he makes that plain and homely, but powerful and characteristic statement, of the different conclusions drawn by an observer from a Stone which he chances to pick up, and a Watch, should he, for the first time, find one. A plate is then given, of the various parts of watchwork taken to pieces, with their names and uses very curiously stated in a note. Sections and figures of the eye and ear follow; then extremely good drawings of the skull and vertebræ, the ribs, bones, and joints of the legs and arms, muscles and tendons of the various parts, the heart, stomach, and other principal organs of the trunk, with the leading vessels separately. There are also two figures, exceedingly well contrived for showing the parts in their connexion, the one enabling us to trace the course of the food from its reception through the alimentary canal, to its final elaboration and reception into the thoracic duct, and the other exhibiting, what Paley calls the packing of the body. After illustrating by appropriate figures of the infantine gums, and the fœtal heart and arteries, the extraordinary provisions of a prospective nature-the preparations made before hand, with a view to a use which is to spring up or arise after a considerable interval of time, there are excellent plates of the duck's bill, the air bladder of fishes, the fangs of snakes, and several other subjects in comparative anatomy; and a plate exhibiting the structure of the sting and proboscis of insects of various kinds, as seen by the microscope. Some very neat figures are also given of the parts of plants; and some fine drawings, in four plates, of the vallisnera spinalis, the cuscuta Europea, the Dionaea muscipula, the colchicum autumnale. There

are also diagrams in one plate showing Saturn and his ring, and illustrating the statement of the planetary motions.

We are the more particular in recounting the nature of the illustrations, because we are very desirous of recommending Mr Paxton's book; and knowing the reluctance of most purchasers of a work, to take a new edition, which thereby seems to render their former purchase useless. But our author has very properly accommodated these unwilling buyers, by publishing the series of his prints, with letter-press descriptions in a separate form. It is, therefore, to be hoped, that no reader of the original book will be without it.

Without any wish to detract from Mr Paxton's merits, we shall throw out a few criticisms, rather by way of hints for the improvement of subsequent editions.

Some of the references are not correct, and the reader is thus puzzled to follow the description. Thus in vol. II. p. 66, note, the reference should be to plate XXXV. not XXXIV. In vol. p. 138. note, a b are called a tendon of the extensive muscles of the toes, instead of b c; and is said to be the flexor of the foot instead of d, and e is called the annular ligament, instead of a.

I.

Several of the plates give important parts too small, perhaps in order to represent their true proportion to the others. Thus in XIX. the receptaculum chyli, and the letters of reference in the figures, are sometimes invisible; a great but very common fault; and in popular works a very inexcusable one. Thus some of the letters in XIX. are not to be observed, and those the most important ones. This can always be remedied by drawing out the reference to the side of the figure, and connecting the letters there with the parts they apply to, by means of lines, as our author has frequently done.

Some useful additions might be made to the book; but of these we will mention but a few. Plate XIX., one of the most important, if not the most important of the whole, instead of being merely an exposition of the course taken by the secretion of the blood, might very well, and without any confusion, pursue some of the other secretions, as the urine and bile-of the former of which we have a very excellent drawing separately. The course of the blood might also be given through the main vessels in the trunk, and to the points where these supply the great limbs. But this would require a separate plate. Perhaps, too, the brain should be given, and the singular variety in the channels of circulation there, adapted to the exigencies and risks of that important viscus.

The notes are, except to explain the figures, somewhat scanty,

and do not point out the defects of the text in almost any material instance. Thus, there are very good figures in Plate IV., and a fit description for explaining the curious mechanism of the nictitating membrane; but the great omission of the text is not supplied, namely, that the contrivance is mathematically exact for giving a great augmentation of velocity, according to the most ordinary principles of dynamics. This could easily have been shown by a few lines, and a single diagram on the plate now referred to. So in Chapter VIII., the text having omitted to note the reason for the different bones of the skull being placed and joined in the way we find them; a very scanty addition is made to this by the single remark, that the vitreous tablet being so brittle is not joined by dovetailing. In discoursing of the eye, Paley falls, we apprehend, into an error in supposing that Dolland was led to his discovery of the different dispersive, which he calls refractive, powers of glasses, by considering the composite structure of the eye. The ingenious papers of that great optician, in the Philosophical Transactions, give the history of his discovery, and they make no mention of this fact-and, indeed, give a quite different history of the discovery, vol. iv. p. 733. At all events, he certainly was not the person who first reasoned to the improvement of glasses, from the construction of the eye, as Paley represents, in vol. i. p. 20, when he says; at last it came into the mind of a sagacious optician to inquire how this matter was managed in the eye,' &c. For David Gregory's Treatise (Catoptrica et Dioptrica Sphærica Elementa) published in 1713, concludes thus: Quod si ob dif'ficultates physicas, in speculis idoneis torno elaborandis, et poliendis etiamnum lentibus, uti oporteat, fortassis media diversæ ' densitatis ad lentem objectivam componendam adhibere utile 6 foret, ut a Natura factum observemus in Oculi fabricâ ubi 'christallinus humor (fere ejusdem cum vitro virtutis ad radios lucis refringendos) aqueo et vitreo (aquæ, quoad refractionem, haud absimilibus) compingitur, ad imaginem, quam distincte ' fieri potuit, a naturâ nihil frustra molienti, in oculi fundo de'pingendam.' Neither Paley nor his commentator have remarked that the eye is not, in fact, an achromatic instrument, without an adjustment; and that if that be altered, or if objects be viewed by one-half of its lenses, the different refrangibility is not correct, and colours are produced-as any one may see, by viewing an object, as a candle or the bar of a window, and covering part of his eye. As he draws the obstacle near the bar, the sides of it will be, one blue, and the other red or orange. Nothing is said too of the singular artifice, on the purest principles of optics, by which the crystalline humour is made more

6

dense in the centre, its substance actually varying. We may note another plain omission under the head of the Bee. Neither under the head of instinct, nor when he is describing the convenience of the comb under that of insects, does Paley give by far the most extraordinary of all instincts and of all the accommodations of the comb; the size of the angles, and their being discovered by mathematicians (through the resource of the fluxional calculus) to be the precise size, which makes the greatest possible saving of room and of materials. This omission, the present edition does not supply.

We have noted these in passing, as a few instances of defects. We should certainly hold it none, that any one branch of the immense subject under discussion was wholly left out; for its vastness, coextensive with all creation, makes a selection the very essence of such a work. But where any subject is introduced, and a very important consideration belonging to it is left out, nay, as in the case of nictitation and of the honey-comb, by much the most striking illustration, it becomes proper to request the learned author's attention to the matter, for a future edition.

When we first gave an account of Paley's work, in 1803, we observed that Natural Theology was a subject which admitted of no originality, and on which we never expected discoveries to be made. We doubt if we should have said so, had we then known that the work which stands next to Mr Paxton's was, after so considerable a lapse of time, to make its appearance. The Treatise on Animal Mechanics possesses very great originality; and may be regarded, not in principle, perhaps, but in applying principles to facts, as having made discoveries.

This is one of those admirable works for which we are indebted to that very important Institution, among the best fruits of the enlightened times we live in, the Society for Diffusing Useful Knowledge, whose proceedings formed the subject of an article in our last Number. The Treatise before us has appeared as a kind of appendix, or practical application of the doctrines of Dynamicks, unfolded in some previous works of the Society, composing portions of the Library now published by them periodically;—and none of these publications has, we believe, given greater satisfaction. By an extraordinary union of profound anatomical and physiological knowledge, with the power of striking illustration, and plain, perspicuous writing, the learned and ingenious author of this work has lent a much more scientific aspect to the doctrines of Natural Theology, than they before had possessed. Indeed, with the exception of Mr Ray, a great naturalist, and Dr Derham, a respectable one, most of the writers who treated on final causes, were divines or moralists,