The theory of Newton that every particle of matter attracts all other particles of matter in right lines joining their centers, and in an inverse ratio to the squares of their distances bj"virtue of an inherent force called gravity, accounted for the motions of the planets so satisfactorily that it has been almost universally adopted by subsequent physicists as a natural law. Nevertheless there have not been wanting those who have doubted the correctness of this theory. Among these Faraday has been perhaps the most conspicuous. Without doubting the fact that 1-yhat we call gravity varies as the squares of the distances, he claimed that the supposition that a single force could so vary was in conflict with the highest law in physical science capable of comprehension by the human mind, namely, the conservation of force. The pamphlet before us is a very modest and calm statement of a doubt in regard to the truth of this celebrated and generally accepted theory, and though metaphysical, as all discussion upon an abstract notion of force must be, calls in mathematics to aid in the elucidation of a new theory which is, that& rdquo; that all planetary movements are caused by the effect of force on matter-not inherent in matter ; and further, that the one primal force on which planetary movement depends, modified by special effects upon substances differing; in kind, in arrangement, and in position, is that which, under the modified conditions, is called by the variOus names of force, as of attraction and repulsion, cold and heat, electricity,magnetism, weight,” etc. The latterof the essay, in which it is attempted to sustainthe theory, are, as the author claims, merely suggestive; the first part being devoted to the attempt to demonstrate mathematically that the theory of Newton is untenable. We are disposed to be lenient withthe errors ot an author who expresses his views 80 temperately and candidly as this, and though it would not be diffiCult to show some defects that, in our opinion, vitiate the whole argument, we do not think the topic of sufficient value to enter upon its discussion. Indeed the author himself asserts that he claims no scientific value for the discussion or the idea which led to it. We must therefore placethisbook among those works of which the world has seen too many; works seemingly written to no purpose but to indulge the love for speculation which has been a characteristic of certain minds in all ages. The Gold Fields and Mineral Districts of Victoria With N otes on the Modes of Occurrence of Gold and other Metals and Minerals. By R. Brough Smyth, F.G.S., Secretary for Mines for the Colony of Victoria. Melbourne : Printed and published by John Ferres, Government Printer. H. T. Dwight, 232 Bourke street, East. London: Triibner&Co., Paternoster Row. This is a compilation in large quarto form; of an immense mass of information, historical, statistical, and technical, relating to the mineral resources of the Colony of Victoria in Australia. The perusal of the volume will, without doubt, excite surprise even in the minds of many Englishmen accustomed to regard Australia as a sort of El Dorado, yet having only a vague and very imperfect idea of the immense resources of that continent. Even many Anglo-Australians have only a partial knowledge of the country they inhabit, a country destined, perhaps, at some period, to play as prominent a part in the history of the world as GreatBritain itself. It would be futile to attempt a review of this work in any space we can at present allot to it. Suffice it to say, that we deem it one of the most important works of its class ever published. As a work of reference it will prove of great value, as it is thoroughly indexed, and also contains a glossary of mining terms, with plates illustrating scenery, also apparatus, implements, etc., used in the Australian mines. The entire work is, moreover, illustrated in a very artistic manner. The reader will And in another column an extract from this work, with an illustration of the “ Welcome stranger Nugget,” found near ,Donolly in Australia, the largest mass of pure gold eyer found native in the history of gold mining. ThE Progress and Condition of Several Departments OF Industrial Chemistry. By J. Lawrence Smith, U S Commissioner to the Paris Universal Exposition, 1867. This is one of the series of able and instructive reports which have been prepared and published.on the great FrenchExposition. We have met w»th no similar document of greater interest and value than this, and we find in its perusal that we shallbe able to select many extracts ofinterest which we shall in due time lay before our readers, premising that some of the deductions of the author in regard to the effect of legislation upon similar industries in the United States do not receive our sanction. An extract from this report, entitled “ Applications and Progress of the Manufacture of Sulphuric Acid,” will be found in another column, and is the iirst of several extracts we shall make upon this, and other important branches of manufacture. USEFUL Information for Railroad Men. Compiled for the Ramapo Wheel and Foundery Company by W. G. Hamilton, Engineer. Second Edition. Revised and Enlarged. New York : D. Van Nostrand, Publisher, 23 Murray street, and 27 Warren street. This is a hand, or rather a pocket book of information in a condensed form, mainly compiled from the standard works of Clark, Colburn, Bourne Haswell, Hurst, Molesworth, Nystrom, Percy, Scribner, Tempteton Ure Price, and Williams, and is filled with useful and practical formula ruleB statistics, recipes, tables, etc., etc., thoroughly indexed, and provided with a rubber clasp, One of those books of reference most useful to practical jaen,and published in admirable style. Railway Economy. Use of Counter-Pressure Steam in the Locomotive Engine as a Brake. By M. Le Chatelier, /Irl,geniew en Chief Des Mines. Translated from the Authors'Manuscript. By Lewis D.B. Gordon, F.R.S.E., Honorary Member of the Institution of Engineers in Scotland. Philadelphia : J. B. Lippincott&Co. There is nothing new in the general idea ofcounter-pressure brakes. As practiced previous to the investigations and inventions of M. Le Chatelier, there were, however, insuperable objections to the employment of the system. These objections are fully set [(>Eth in the little work before us, as well as the progress of the experiments by which such an important modifi cation of the system has been made, that, at the present date, upward of twt> thousand engines are running in France and Spain with this improvement attached, and it is also being introduced on the German railways. We have now in process of preparation an engraving of this improvement, and will ggive, in a future number, all necessary explanatory details in regard to it. We are in receipt ot the first number of a neally-printed quarto sheet called The Polytechnic, a semi-monthly of twelve pages, Montague L. Marks, editor and proprietor, 208 and 210 River street, Troy, N. Y. The prospectus informs us that the design is to establish this paper permanently as a high-class college scientific publication, to be increased both as to quantiity and quality of Us contents according to the amount of patronage it may receive. Tlie connection ofthis paper with the Rensselaer Polytechnic Institute gl ves it command of many resources, both from the talent always to be found in that excellent school and from the alumini, among whom are many of our best engineers and scientific men, The first number is spirited and its contents are interesting. 'We wish our new co- temporary the success it merits. Subscription price per annum.