a careful and sober-minded inquirer he could not have failed to find the superabundant refutation of what he calls his " arguments" and his "suggestions." He cannot see that "because a puddle in a rainstorm will cut runlets in the soft sand in an hour or two, it must follow that rain or running water will cut glens and valleys, or even sever high mountains, granted millions of years." Minds less filled with prejudices find in this no difficulty. The author ignores the fact that geologists only take up the history of the earth when no longer a nebular or an igneous mass. Consequently when Prof. Huxley speaks of a very remote period when the earth was passing through physical and chemical conditions which it can no more see again than a man can recall his infancy," he does not of necessity contradict Lyell when the latter declares that "the forces now operating upon earth are the same in kind and in degree as those which in the remotest times pro-duced geological (but not pre-geological) changes." "Verifier" asks "If Nature were still carrying on operations by which the globe was made and fashioned, only on a diminished scale, are we not in the first place entitled to expect to catch her in the act of producing some of those elementary substances which enter into the composition of the earth's crust; not of depositing but of creating the metals and simple minerals, gold, silver, tin, quicksilver, iron, the diamond, emerald, &c.? In no instance has any such discovery been made." This is obviously an adaptation of the well-known anti-Darwinian argument, that no one has ever seen an animal or plant in the act of evolution. This objection is obviously of very little value, but as applied by "Verifier" it is even more unreasonable than in its original use. The transformations of organic beings might naturally be expected to take place on the surface of the earth, and if of a nature to attract attention might conceivably be noticed by man. But if elementary substances are being now created there is a very strong probability that the operation would take place underground, where no human eye could possibly witness. Again, is it not probable that all the materials of which our reputed elements consist have been used up in the production of such elements? It will be quite time enough to ask why we never witness the creation of gold when our chemists have detected a something out of which it could be created. Further still, supposing that tin or iron were in some place being actually created and not deposited, how could we assure ourselves that such was the fact? Suppose "Verifier" is standing by the side of a rock and sees a deposit of any metal forming upon its surface, and that with sufficient speed to be noticed, is he aware of the precautions necessary to prove that this is not a mere case of deposition? He tells us that "the sand and mud washed down into the Mediterranean by the Rhone in the days of Hannibal remain to this day incoherent sand and mud." How does he know this? and, painful as the question may sound to him, what is it to the purpose if so short a time of exposure to the action of the sea should produce no decided action? We must therefore utterly repudiate his "obvious conclusion" that the conditions under which these substances were formed exist no longer. "Verifier" next takes his stand upon metamorphism, by which he says, "sandstone may have been converted into quartz-rock, or even into granite." He ought to be aware that sandstone or quartz alone can never form granite, as two other constituents are requisite. To some, he tells us, "hot water charged with chemical carbonates seems to have been the agent" of metamorphism. Why some carbonates should be designated as "chemical" we are not sufficiently versed in pseudo-scepticism to comprehend. He asserts that "it has been impossible to realise metamorphism, or even to imitate it in the laboratory," and imagines he has reached "one unmistakable conclusion, viz., that metamorphism is a thing of the past, its processes not now discoverable, and it must therefore be dismissed from the category of Causes now in action.'" If, however, the author had taken the trouble to make himself acquainted with the results of modern scientific research, he might have become a wiser and a less confident man. The researches of Messrs. Daubrée, Sterry Hunt, and others have decidedly proved that metamorphism can be imitated in the laboratory, and that neither a large quantity of water nor a very high temperature is requisite. We would recommend him to read the "Annales des Mines" (Ser. 3, vi., 78; Ser. 5, xii., 289; Ser. 6, vi., 78), "Memoires Academie des Sciences" (xvii., 1860), "Bulletin de la Soc. Geol. de France" (Ser. 2, iii., 547), "Ann. de Chimie " (xxiv., 258), " Quart. Journal Geol. Soc. of London" (xv., 488). His assertion that metamorphism is not still going on is utterly unproven, and it is, to say the least, contrary to all probability. There are certainly metamorphitic rocks which have been produced at comparatively recent dates. From the very nature of the case we cannot expect to "assist" -in the French sense of the word-at the process. Why metamorph products should be more common among the older than the more recent formations must be self-evident to every geologist. Turning to another part of the book, we find the assertion that earthquakes are most common in plains and low grounds. This is exactly the reverse of the truth: the great earthquake regions-the western coast of South America, the West Indies, New Zealand, Iceland, Japan, the Malay Islands (excluding Borneo, which is more level), Calabria, the Iberian Peninsula, and the Greek Islands-are all mountainous. On the other hand, the vast plains of Eastern South America, of Central and Eastern Europe, and Northern Asia, are almost free from earthquake action. There can surely be no occasion for us to wade further through a book in which the plainest facts are denied or misinterpreted, and in which the all-important evidence of palæontology on the former elevations and subsidences of lands, and on their alternating connections and disconnections, is left out of view. A real Scepticism in Geology" would be welcome, and would do the world good service, but it must produce very different evidence and be written in a totally different spirit from the book before us. "Verifier" has been nine centuries too late. A Treatise on the Law Relating to the Pollution and Obstruction of Water-courses, together with a Brief Summary of the Various Sources of Rivers Pollution. By CLEMENT HIGGINS, M.A., F.C.S., Barrister-at-Law. London: Stevens and Haynes. It is only under very exceptional circumstances that we can, with either benefit to our readers or credit to ourselves, presume to give an opinion concerning the merits or the defects of a work on any branch of law. Even in a case like the present, where we may lay claim to some acquaintance with, and at any rate a deep interest in, the subject-matter of the laws expounded, we can only deal with what may be called collateral issues. We may be able to discuss the question as to what constitutes "pollution" in a river. We may show the impracticability of certain standards that have been laid down, and point out others more feasible and rational. But the interpretation of statutes we must dismiss as a matter not within our competence. The treatise before us is divided into two parts. The first of these is devoted to an exposition of the "Rivers' Pollution Prevention Act" of 1876. The author examines what constitutes an offence under the Act as to solid matters, sewage pollution, manufacturing refuse, and mining pollutions, and then treats of the institution of proceedings, and of facilities for conveying the refuse of factories into sewers. It is in this part of the work only that certain chemical questions arise. What constitutes "pollution" is the first difficulty. The author remarks that "The successful working of the Act will much depend upon the meaning placed upon the word "polluting" as therein used by those with whom its interpretation rests. It may be comparatively easy to determine whether any particular manufacturing, mining, or other refuse is poisonous or noxious, but it is certainly far more different, on account of the different meanings placed upon the word, to say whether it is or is not polluting. No attempt has been made by the framers of the Act to define the word, but they are content to say merely that the term "polluting" shall not include innocuous discolouration." This exception seems to us an element of danger. No one can contend that the colouring matters of logwood, fustic, peachwood, &c., if present in a river are likely to be injurious to man, beast, or plant. But who knows what accompanying and really noxious pollutions they may hide? On this account we think that transparency and the absence of colouration are characteristics to be desired, especially as they may be attained by known. methods. The author continues :-" Neither do the decisions of the judges either in courts of law or equity furnish a definition of the word such as to meet the requirements of the Act." As the only way of solving the difficulty he gives a summary of the expressed opinion of scientific men. Under this head we find once more the recommendations of the Rivers' Pollution Commissioners, on which surely nothing further need be said, especially as they have not been deemed fit for legislative adoption. Mr. Higgins gives along with them some-though by no means all-of the objections raised against them. He then quotes with marked approval the two recommendations given by Mr. Crookes, F.R.S., in his evidence before the Committee of the House of Lords. These are simply that the river itself should be the standard of purity, and that no liquid should be permitted to fall into a river if such liquid contains a greater percentage of impurity than the river itself. These suggestions, Mr. Higgins thinks, may be safely followed by county court judges in their decisions under the Act. As regards solid matter thrown into rivers another difficulty arises. "No offence against the Act is committed unless the solid refuse, rubbish, cinders, or other waste or putrid solid matter finding its way into the river results either in interfering with its due flow or in polluting its waters." Here, we fear, the Act is scarcely stringent enough. The gradual silting up of rivers from natural causes is a source of danger which requires to be jealously watched and contended against, as the records of the past winter will show but too plainly. Surely, then, it is intolerable that the evil should be intensified by the sloth or the greed of those who would make the rivers general depositories of filth and refuse of all kinds. On this subject the Rivers Pollution Commissioners in 1868 spoke very judiciously. They recommended that not merely "the casting of solid matter of whatever kind into rivers and running water" should be prohibited, but also the placing of solid refuse in such positions on the banks of rivers as to render it liable to be washed away by floods." They also suggested that any Act passed for this purpose should take effect immediately. In treating of sewage and of liquid manufacturing refuse, Mr. Higgins, though himself a chemist, and far better qualified to speak on the subject than many who have come forward as the instructors of the public, does not enter into the comparative value or efficiency of the various methods of dealing with polluted waters. He even reminds manufacturers, municipal and sanitary authorities, &c., that "it is not the business of the Courts to give instructions in sewage purification. The second part of the work is devoted to "Riparian Rights and their Protection." The author treats of such rights arising ex jure naturæ, or by way of easements or custom, of their protection by injunction or by an action for damages. The appendix contains statutory provisions relative to water-courses and the vesting of sewers, There are also tables of statutes and of cases. As far as we are capable of judging this work is a valuable contribution to the literature of the sewage question, the law of which, as well as its chemistry and its engineering, requires to be brought clearly before the public. The New Formula for Mean Velocity of Discharge of Rivers and Canals. By W. R. KUTTER. Translated from articles in the "Cultur-Ingénieur," by LOUIS D'A. JACKSON, A.I.C.E. London and New York: E. and F. N. Spon. THE author tells us in his preface that "while the lead in engineering progress generally, both theoretical and practical, seems to have been almost entirely taken by the English-speaking races, and whilst improved construction, perfected appliances, and higher economy have progressed in the last thirty years at a speed perhaps greater than has ever been previously known, yet in the hydraulic branches of engineering no similar claim can be very satisfactorily made out for our own country. This seems at variance with our present requirements. We have in India a vast empire existing in a state of mutual dependence with England, whose enormous wealth is dependent on its population, whose population is dependent upon agriculture, and whose agriculture depends chiefly upon irrigation; where water is like silver, and the science of its judicious application and control is like gold. We have in semi-tropical regions large colonies which suffer from devastating floods alternating with drought." Thus far we are with the author; the evils which he has enumerated might doubtless be obviated by a proper system of reservoirs to catch the rains when they fall; of by. washes to carry the surplus part through towns and cultivated lands without occasioning devastation, and of conduits for the judicious distribution of the stored-up water in the dry season. To do these things is the work of the hydraulic engineer, and if he is to do them well he must not be required to work upon erroneous data. Two incidents in our modern domestic history -the Holmfirth and the Sheffield floods -confirm the author's view that hydraulic science-at least in its practical applications -has not progressed amongst us as might be desired. Is it |