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which comprises the Poetical Books of Scripture, and which, to a large number of readers, will present stronger attractions than any of those which have preceded it. Suffice it, then, to say that the able and interesting introductions to the Book of Job and to the Psalms serve to enhance the high estimate. which we had formed of the learning and judgment of Canon Cook; that much light is thrown upon the historical interpretation of the Psalms, as well as upon their critical and exegetical meaning, both in his own notes and also in those of the learned and accomplished Dean of Wells; and that the thoughtful and suggestive introduction to, as well as the notes upon, the Book of Proverbs are not unworthy of the high reputation of Professor Plumptre.

The typography and the general execution of these volumes are highly creditable to the distinguished publisher who has taken upon himself the entire responsibility of this great work, as well as to those who have actually carried it through the press. We observe, with satisfaction, that numerous alterations and corrections have been made in the later impressions of the first volume. We trust that the work of correction will be extended to the later volumes; that some of the introductions and notes will be thoroughly revised, if not rewritten and that the whole of the critical notes of Canons. Espin and Rawlinson, involving points of Hebrew scholarship, will undergo a careful revision at the hands of some competent Hebrew scholar. Should these emendations be madeso far as it is possible to form any estimate of the forthcoming portion of this work from the names of those scholars to whom the remaining Books of the Old Testament, and those of the New Testament, have been assigned-we confidently anticipate that the Speaker's Bible will take its place upon the shelves of our theological students, not only as the best and most exhaustive critical and exegetical Commentary which England has yet produced, but also as affording one of the most favourable specimens of the advanced Biblical scholarship of the nineteenth century.

ART. III.-1. The Moon: considered as a Planet, a World, and a Satellite. By JAMES NASMYTH, C.E., and JAMES CARPENTER, F.R.A.S. 4to. London: 1874.

2. The Moon, her Motions, Aspect, Scenery, and Physical Condition. By RICHARD A. PROCTOR, B.A., F.R.A.S.

London: 1873.

3. Théorie du Mouvement de la Lune. Par M. DELAUNAY, 'Mémoires de l'Académie de Paris.' 2 vols. 1860-67. 4. Fundamenta Nova Investigationis Orbitæ veræ quam Luna perlustrat. By Professor P. A. HANSEN. Gotha: 1838. THE

HE earth's bright satellite has always been an object of affectionate reverence among the sons of men. In the early days of human history magnificent temples were reared in expression of this feeling. In the present age no less costly buildings are erected and maintained at the public charge, where large bands of carefully-trained and well-appointed ministrants keep watch and celebrate their solemn rites, night after night, in the same service. But perhaps no more noteworthy illustration of the charm which this particular devotion has, even for unimaginative and unimpressionable philosophers, could be found in the annals of human history than is expressed in the beautifully illustrated volume which has just been published under the conjoint authorship of James Nasmyth and James Carpenter, and which really represents more than thirty years' almost unintermittent study and application on the part of a mechanical engineer, who is distinguished amongst his contemporaries and compeers alike for the hard practicality of his head, the adroit readiness of his hands, and the finished cultivation of his taste. The James Nasmyth alluded to in this remark, it will scarcely be necessary to say, is the civil engineer so well known as the inventor of the steam-hammer and of the steam machinery for driving piles. In his schoolboy days, while still attending the classes of the High School at Edinburgh, James Nasmyth was led, by an accidental acquaintance with the son of an ironfounder, to study closely the various processes of casting and forging iron. He had also inherited a strong taste for drawing, being himself the son and grandson of two eminent Scottish artists, and he fostered this taste under the facilities and training which were at his command in the courses of the then recently formed school of arts of the Scotch metropolis. Not very long after the completion of his univer

sity career he began to give some attention to the investigations of astronomy, and was very soon deep in the construction of reflecting telescopes of large size and considerable power. On June 14, 1844, just thirty years ago, he communicated, as one of the firstfruits of his labours in this direction, a paper to the Royal Astronomical Society, describing Certain Telescopic 'Appearances of the Moon,' and exhibited, in illustration of this memoir, a drawing and model representing the aspect of a part of the lunar surface as it appeared in his telescopes under high magnifying power. The tract of the lunar surface which was dealt with in these illustrations is a broken region immediately surrounding the large crater known as Maurolicus, and both drawing and model were made by a telescope of twelve inches' aperture magnifying in linear dimensions 360 times, and were upon the scale of one-eighth of an inch to the mile. About a couple of years after this time, we ourselves had in our possession a copy of a very large drawing of some lunar craters, that had been used by Captain Owen Stanley in one of his lectures, and which was also made by Mr. Nasmyth. This sketch was the prime original of the remarkable group of craters associated with Theophilus, Cyrillus, and Catharina, which appears among the illustrations of the book now under notice. When the memoir on the Telescopic Appearances in the 'Moon' was communicated to the Royal Astronomical Society, its author had been already in close observation and study of the lunar disc for some years, in the conviction that it furnished a very admirable and instructive means of illustrating certain grand features of volcanic operations. In one part of the memoir he drew pointed attention to the brim'ful' crater, which is now presented in the illustrations of the book as Wargentin. The memoir of 1844, which occupied two pages of the sixth volume of the Monthly Notices of the Astronomical Society, was indeed essentially the protogerm of the noble quarto volume now before us. In the brief early memoir there are traces of the leading thoughts that have been developed in the finished book.

Two distinguishing characters mark Mr. Nasmyth's monograph from the hundred and one treatises that have touched upon the same theme. These are, in the first place, the marvellous beauty and accuracy of the pictorial illustrations, which are altogether without parallel in this branch of art; and in the second place, the lucidity and completeness with which the anthor's views of the moon's physical condition, and probable formative history, have been put into words. The treatment of the subject in this monograph is that of a mind which has

been trained in the methods and discipline of mechanical and engineering, rather than of astronomical and mathematical, science, and which has acquired a very firm grasp of the matter on what may be termed its practical side. It is not too much to say that, under the impress of these characteristics, the book is the most complete and intelligible description of the physical condition of the moon that has yet been published.

In alluding to the exquisite delineations of the typical features of the lunar physiognomy with which his volume is illustrated, Mr. Nasmyth explains that these are the results of more than thirty years of continued study and work. Drawings of the various objects here represented were, in the first instance, made at favourable opportunities when high powers of the telescope could be satisfactorily and advantageously used, and these drawings were then subsequently re-examined in comparison with their originals, and retouched, corrected, and amplified, time after time, until they at last seemed to the practised eye of the artist as perfect as the equally practised hand could render them. In this completed form they were next turned into models in bold relief; these models were afterwards photographed in appropriate positions in strong sunshine, and from these photographs the prints that appear in the book were for the most part finally made by the heliotype process, in permanent pigments which are as fixed and enduring as the ink of ordinary copper-plate engravings. The finest of these pictures actually reproduce to the eye the appearances that are seen in the moon by the aid of high powers of the telescope, applied under the most favourable conditions of lighting and atmosphere. They nearly all of them deal with bold characteristics of lunar scenery, and in many of them the reproduction is so perfect that it seems to an experienced eye as if the old familiar reality were before it when it rests intently upon the pictorial rendering. Even the peculiar frosted-silver texture, and the indescribably delicate frettings and frecklings that start out from the lunar surface in passing instants of the nicest telescopic definition, are there, as mint marks of the coin. Ready proofs of this statement may be especially found in the delineations which represent the terraced landslips, and circumambient mottling of froth-craters, that surround Copernicus-the lunar Etna of Heveliusand the walled hollows of Aristotle and Eudoxus; the long yawning void chasms that shatter the ground near Triesnecker; the bulwarked floors of Shickard and Wargentin;

the serrated shadows of the sombre abyss of Plato, with its sentinel peak Pico, and its clustered outwork of Alpine summits ploughed through by a broad flat-bottomed valley; and, perhaps, before all, the clustered peaks and shadow-fringed chain of the mighty Apennines, with the fissured crackings of the surrounding plain. These particular drawings are certainly as successful an attempt to present, in a pictorial form, what the highest powers of the telescope reveal in this weird field of investigation, as it is possible for the most sanguine enthusiasm to conceive. The result is in these instances beyond all praise. The long, patient, painstaking labour, and the consummate skill of the artist, alone can explain how such marvels of pictorial verisimilitude have been produced by photographing artificial modellings.

Before entering definitely upon the consideration of Mr. Nasmyth's views of the physical condition and history of the moon, it may be well to ask the reader to place compactly before his mind, in a broad, general form, an idea of what the body is that is concerned in the explanation. The moon, it will be remembered, is a solid sphere of material substance having nearly the intrinsic density of flint glass, and of such size that it reaches to about the forty-ninth part of the volume of the earth, and has therefore a surface-area something less in extent than a fourteenth part of the surface of the earth, comprising in exact numbers 14,567,000 square miles. The size and density of this sphere, thus apportioned, are of such amount that the force of gravity upon its outer surface must be not more than a sixth part of the same force upon the earth, so that a heavy body shot off from the outer surface of the moon by any given projectile effort would go six times as far under the impulse as it would if started from the earth's surface in the same way. But the spherical mass thus circumstanced in the matter of size and density, is a bare round ball of solid substance, destitute of all trace of atmospheric investment, whether of vapour or air. The absence of gaseous atmosphere, of whatever kind, in the moon is definitely proved by the simple fact that whenever its opaque body passes along in the sky in front of a fixed star, the shining point is concealed by the passage of the intervening dark body within an immaterial trifle of the time that it ought to be upon the assumption that the occulting body is bare of all gaseous or vaporous investment, which, if present, would have kept the star for some time in sight when actually behind the moon, as the sun is brought into sight by atmospheric refraction when

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