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and "Mediterranean" forms, once separated by a land ridge from Scotland to Iceland.
All fish ultimately depend on plant-life for their food. In the ocean floating plants are all-important, minute unicellular organisms living in incredible numbers in the upper layers of the water, in suitable conditions daily multiplying themselves, giving a fertility
FIG. 2.-Floating plants, mainly Ceratium.
to the sea many times that of the best soil. The cycle of life of such pelagic plants in the open ocean is simple, complicated only by fluctuations in sunshine, rainfall, and other meteorological conditions. In coastal waters, especially where broad shelves extend out from the land, such fluctuations are more considerable, and often
enormous seasonal changes in temperature and salinity have to be added. Instead of the
same species of plants all the year round, and in consequence of the smaller animals which feed upon them, there may be a whole series of species, each suitable to some particular phase of seasonal change. Form succeeds form, the old form disappearing, perhaps passing into resting stages upon the bottom, until suitable physical conditions bring them once more into active life. It seems possible that this very destruction and re-creation adds further to the total food of our seas. The peculiar richness of the fishing grounds is, however, mainly ascribed to the abundant landdrainage of western Europe with its teeming population, to this being due much of the nitrogen, phosphorus, and silica in forms available for living 3 organisms.
period of its life, its own wanderings in search of food, etc., and its own peculiar development. The plaice has its southern limit at the isotherm 10° C. The North Sea stock spawns in February, principally off our coasts between Dover and Cromer, and the eggs and young require to be carried by the currents so that the latest larval stages fall on the bottom in not too great intensity in a few feet of water, which must have a salinity of at least o-017. Naturally the Dutch coast is the great plaice nursery, and from here the young fish gradually disperse into deeper and deeper waters, at the same time becoming more suitable to the food they produce, until in their fourth season they undertake their first breeding migration. The eggs, which are somewhat corrugated, have been found carried into the Baltic in undercurrents of warmer Atlantic water, a phenomenon considered to be correlated mainly with viscosity. Growth is a matter largely of temperature and salinity. Thus in the North Sea a fish of 40 cm. long is six years old, as shown by its otoliths, and in Barents Sea (White Sea) about eighteen. The latter rate of growth is found in the brackish Baltic, where 40 cm. and eighteen years are about the limits as contrasted with 70 cm. and fifty years in Barents Sea.
The herring is a feeder on the floating life of the sea, and rises and falls in the water by night and day, shunning the light. It exhibits somewhat similar rates of growth to the plaice as shown by its scales, which form broad, transparent growth-bands in summer as contrasted with narrow, opaque bands in winter, the fish not shedding its scales during its life. By the study of the breadths of the summer bands the areas where fish spent their previous lives may be ascertained, and thus breeding shoals may be analysed. Maturity is reached in different localities in from three to ten years. The spawn is laid on the bottom and at 3° C. hatches in forty days, at 12° C. in eight days. The young are at the mercy of the currents, and good years off Norway are considered to be those in which spawning is late, the currents being more determined and the sea having abundance of minute and suitable plant-life as food.
Prof. Gardiner concludes with a plea for the continuation after the war of the International Council
FIG. 3.--Rates of Growth of Herring. Eight fish of equal age (four years) from: 1. White Sea; 2, Lysefjord, Norway; 3, Zuyder Zee; 4. East Coast of Sweden; 5, West Part of North Sea; 6, Atlantic Ocean; 7, Iceland; 8, West Coast of Norway (Spring Herring). (After Hjort).
Most fish are bottom-feeders, and the ground must be suitable to the animals upon which they feed. Mud, the de- 4 position of which implies the absence of movement, is inimical to all life. Flat fishes are themselves only suited to sand, on which they rest, invisible to their enemies. The cod and haddock prefer respectively rock and sand, but the hake, ling, coalfish, and whiting, belong to a family of such remarkable adaptability in feeding that it is of vast economic importance. The herring deposits its spawn on rocky ground, so that its eggs get well aerated and are not silted over, but most other economic fishes have floating eggs.
As examples the plaice, cod, herring, mackerel, and eel are chosen. Each has its own spawning grounds, its optimal depth, salinity, and temperature at each
for the Exploration of the Sea, which came into existence in 1902. Any control of the West European fisheries must be by international agreement, for which, as he says, there must be a foundation of incontestable evidence. The conferences of the representatives of the twelve countries on the International Council have been highly profitable in the investigations of the economic conditions of fisheries, depend
ing as these do on immense and fundamental scientific problems. Any fishery agreement is useless unless all neighbouring countries are signatories, and the matter is one of the food of a vast number of the human race. Furthermore, in the extension of such international institutions lies the best hope of permanent peace.
UNIVERSITY AND EDUCATIONAL
CAMBRIDGE.-Prof. Albert C. Seward, professor of
THE Medical College of the University of Cincinnati received several large donations during July. We learn from Science that Mrs. Mary M. Emery promised the University the sum of 50,000l. for a new medical college building, on the condition that an additional 50,000l. be raised by July 1 for its equipment and maintenance. At the appointed time, Dean C. R. Holmes, of the College of Medicine, announced that the 50,000l. had been secured. The sum of 6000l. has just been raised by citizens of Cincinnati for the purpose of maintaining for three years a chair of medicine in the Medical College. The chair will be known as the Frederick Forchheimer chair of medicine, in honour of the late Dr. Frederick Forchheimer, who was for years professor of medicine at the Medical College.
THE new metallurgical buildings at the University
has been erected forms an important addition to the
THE Department of Technology of the City and Guilds of London Institute has issued through Mr. John Murray, Albemarle Street, London, W., at the price of ninepence net, its programme for the session 1915-16. The programme contains the regulations for the registration, conduct, and inspection of classes, the examination of candidates in technological subjects, and the award of teachers' certificates in manual training and domestic subjects. We notice that the syllabuses in both coal-tar distillation and intermediate products and in electro-metallurgy have been revised, that in boot and shoe manufacture has been redrafted, and the revised syllabus in mechanical engineering issued separately last session is now included in the The conditions governing the award of programme. full technological certificates in painters' and decorators' work, cabinet-making, bookbinding, and embroidery have been modified, and the lists of works of reference have been revised. The department now
examines in more than eighty separate branches of technology, and the constitution of the examinations board, the representative character of the panel of consultative examiners, and the large number of practical men among the acting examiners, all provide convincing evidence of the pains taken by the executive committee to ensure that thoroughly practical teaching, based consistently upon sound scientific know. ledge, shall be given in the technical institutions throughout the country.
THE Board of Education has issued its Regulations for Technical Schools, etc., in England and Wales for the session 1915-16. They are not, except for minor matters, materially different from those of last year. The arrangement as to the payment of a fixed, or inclusive (as it is now termed), annual grant in respect of any efficient school occupying a definite educational place in the area and providing approved courses of instruction covering five or more years, is now extended to apply to senior or advanced courses, and the Board will also under certain conditions pay an inclusive grant to a local authority in respect of all courses carried on under its direction for the year 1915-16, and grants may be paid for the year 1914-15 calculated Examinations upon the courses upon the same basis.
of study must be held by the teachers in each year,
IN October next the Athenaeum proposes to start a
important journals into consideration. If all who are engaged in preparing general subject-indexes were to agree as to which periodicals should be indexed, and were to publish beforehand the names of the periodicals they proposed to index, it is possible that such action might have influence upon authors who have not yet decided where they should publish. Unfortunately the periodicals excluded from the list will immediately show cause why they should be included. We have no doubt that the Athenaeum will find a way of dealing with this difficulty, and we wish our contemporary success in its new undertaking.
SOCIETIES AND ACADEMIES.
Royal Society, June 28.-Dr. Peach, F.R.S., vice-president, in the chair.-Prof. J. W. Gregory: Contributions to the geology of Benguella and some Cretaceous Echinoidea from the north of Lobito Bay.-G. W. Tyrrell Notes on rocks obtained in Angola by Prof. Gregory.-R. B. Newton: Some Cretaceous shells from Angola.-G. C. Crick: Some Cephalopoda from Benguella.-Mrs. Margaret F. Romanes: Notes on an Algal Limestone from Angola. These six connected papers were based on the visit in 1912 of Prof. Gregory to Angola and Benguella, Portuguese West Africa, and on the material collected and brought home by him. The earliest explorers of this region were Livingstone, who described the chief features of the physiography, and Cameron, who discovered Cretaceous rocks as well as widespread distributions of granite and gneiss. The Cretaceous rocks begin on the coast and end inland in great conglomerates at the floor of the old plateau of gneiss. The following conditions were recognised and described: Bihé Sandstones consisting of soft beds giving rise to the wastes known as the "hungry country "; Oendolongo sandstones, rhyolites, and tuffs, often like the Old Red Sandstone, referred by some to the Devonian, by others to the Torridonian; Lepi greywackes with cherts, tuffs, and slates; Huambo Quartzites, pre-Torridonian. The coast is traversed by numerous step faults, cutting through the Cretaceous rocks. The fossils of these rocks are described by R. B. Newton. A number of the species are new to the area.-W. F. P. M'Lintock: The zeolites and associated minerals from the tertiary lavas around Ben More, Mull. The peculiar facies of vesicle-minerals in a belt of lavas traceable from areas free from contact metamorphism up to the margin of one of the big acid intrusions is described. The non-metamorphosed rocks are albitised olivine basalts, in which the olivine is completely, and the augite partially, chloritised. The vesicles are filled with chlorite, albite, epidote, prehuite, and scolecite deposited in the order named. Frequently these minerals are seated upon a coarsely crystalline layer of albite, augite, magnetite, and chlorite, with which
the vesicle is lined, and it is concluded that the cavities were filled during the cooling of the lava. By contact metamorphism the contents of the amygdales of the lavas around the margins of the intrusion have been altered; the chlorite has gone to hornblende, the scolecite to prehnite, epidote, and ultimately to garnet; the prehnite, to epidote and garnet; whilst the epidote is replaced by garnet and aphene. The effect of the metamorphism has been generally to build up the minerals in the reverse order to that in which they were originally deposited in the vesicles.-R. C. Mossman: A see-saw of atmospheric pressure, temperature, and wind velocity between the Weddell and Ross Seas. By a comparison of the departures from the normal for each of these data during the years 1902-4, 1910-12 evidence was obtained of an opposite
phase relationship or see-saw of meteorological conditions over these seas. The discussion formed part of a much wider inquiry into the meteorology of antarctic regions.-W. J. Walker: The magnetic quality of iron and steel as affected by transverse pressure. The compressing force acted perpendicular to the direction of magnetisation. The induction measured ballistically. The general result was diminution of susceptibility with increase of transverse pressure; but there were variations from this general result which demanded further investigation.-W. Hill Chalk boulders from Aberdeen and fragments from the sea-floor off the Scottish coast; and notes on the structure of the chalk occurring in the west of Scotland. These important papers were found among the author's possessions after his death.-Prof. E. Topsent: Supplementary paper on the sponges collected by the Scotia Scottish National Antarctic Expedition. Dr. R. Kidston: The fossil plants of the Forest of Wyre and Titterston Clee Hills coalfields. With remarks on the geology of the coalfields by T. C. Cantrill and E. Dixon.
Academy of Sciences, July 26.-M. Ed. Perrier in the chair.-G. Bigourdan: The unpublished correspondence of the astronomer, J. N. Delisle.-J. Boussinesq: The importance of the rudimentary dynamics of Aristotle
the progress of Mediterranean civilisation.-C. Gutton An induction balance designed for the detection of buried shells in ground under cultivation. Owing to the danger to agriculturists due to the presence of unexploded shells buried in the soil and the liability of explosion owing to contact with a plough, the author has devised a modification of the Hughes induction balance by means of which two persons can thoroughly explore a hectare of land in about three hours.-J. Maldiney: The retarding action of sugar in the development of photographic negatives and the permeability of gelatine to the metolhydroquinone developer, used alone or with sugar. A plate giving a complete image in five seconds under the influence of the developer alone can be retarded by the addition of sugar, the addition of 60 grams of sugar per 100 c.c. of developer causing a retardation of from three to five minutes. The action appears to be due to physical causes, the increased viscosity of the solution rendering the penetration of the gelatine emulsion slower.
National Academy of Sciences, July 15 (Proceedings No. 7, vol. i.).-W. S. Adams and F. G. Pease: Nova Geminorum No. 2 as a Wolf-Rayet star. A continuous series of observations on Nova Geminorum No. 2 has shown the development of the spectrum of this star through the successive stages characteristic of novæ into one very strongly resembling that of planetary nebula; and then, by the gradual elimination of the nebular lines and their replacement by WolfRayet bands, into a spectrum identical with this characteristic type of stellar spectra.-A. A. Michelson: The ruling and performance of a 10-in. diffraction grating. A 10-in. grating (actual ruled surface 9.4 in. by 28 in.) having a theoretical resolving power of about 660,000, shows an actual power of about 600,000. The methods of obtaining exact ruling is also discussed.-E. E. Barnard: A singular dark marking on the sky. From a dark object in Cepheus and those in Taurus the author gets the impression that the interstellar spaces are suffused with a feeble nebulosity and that the dark marks are due to the projection upon this background of nearer dark, opaque objects. A. L. Parson: A highly sensitive electrometer. The principle of working in a condition approaching instability is used to increase greatly the sensitiveness
of electrometer, and obtain an instrument theoretically sensitive enough to detect 10-6 volts (though unsteadiness makes it as yet impossible to detect an isolated potential-difference of less than 3 x 10-5 volts). -C. Wissler: The distribution and functions of tribal societies among the plains Indians: a preliminary report. Field-work conducted by the writer and his associates in the American Museum of Natural History leads to the conclusion that the societies have spread from tribe to tribe by culture diffusion of a desultory kind; that certain features of organisation are traceable to particular tribes, and no one tribe can be the originator of the society system as a whole.-T. W. Richards and L. B. Coombs: The determination of surface tension. Attention is directed to various sources of error in the measurement and in the calculation of surface tension by the capillary-tube method, an improved form of this method is described, a new correction for the meniscus is proposed, and exact measurements with a number of liquids are presented.-Ales Hrdlička: An exhibit in physical anthropology. The exhibits prepared under the direction of the author for the Exposition at San Diego are described briefly to indicate their breadth, their permanent value, and their capability of forming the foundation of an anthropological centre.-T. W. Richards The compressibilities of the elements and their relations to other properties. This paper records all the recent work on the compressibility of the elements performed at Harvard, reduced to the best available standard-the newly-determined compressibility of mercury. It is pointed out that the reciprocals of the melting points are very closely associated with the coefficients of expansion, and that both these properties seem to be essentially connected with atomic volume and compressibility.-E. B. Frost: Radial velocities within the great nebula of Orion. We must alter our conceptions of the nebula as an enormous mass of quiescent gas, and regard it as seething with local whirlpools, besides perhaps having a considerable motion of rotation as a whole.-W. S. Adams: The radial velocities of the more distant stars. The radial velocity of stars increases rapidly with the proper motion, and only very gradually with the spectral type. This agrees with Eddington's hypothesis that the relation between velocity and spectral type may be a relation between velocity and distance.T. H. Morgan: Localisation of the hereditary material in the germ-cells. The chromosomes not only furnish a mechanistic explanation of Mendelian heredity, but in the case of non-disjunction and in the case of the point by point correspondence between the linkage groups and the chromosomes, furnish a verifiable explanation of the results. In the case of crossing-over and of interference the chromosomes give us the only objective explanation of the results that has been as yet offered.-G. P. Merrill: Researches on the chemical and mineralogical composition of meteorites. Abstract of extensive investigations which will appear as a memoir in the series of Memoirs of the National Academy.-W. B. Ford: The representation of arbitrary functions by definite integrals. The function f(x) is represented as the limit of a definite integral depending on a parameter when the parameter becomes infinite, or by a series of definite integrals.J. B. Murphy and J. J. Morton: The lymphocyte as a factor in natural and induced resistance to transplanted cancer. A marked increase in the circulating lymphocytes occurs after cancer inoculation in mice with either a natural or induced immunity. When this lymphoid reaction is prevented by a previous destruction of the lymphoid tissue with X-ray the immune states are destroyed; hence the lymphocyte is a necessary factor in cancer immunity.-W. D. MacMillan:
Some theorems connected with irrational numbers. The presence of the factors i-jy in the denominators of series rising in celestial mechanics does not affect the domain of convergence of the series, provided; is a positive irrational number which satisfies a rather mild condition.
Descriptive Geometry. By H. W. Miller. edition. Pp. 149. (New York: J. Wiley and Sons, Inc.; London: Chapman and Hall, Ltd.) 6s. 6d. net. Fighting the Fly Peril. By C. F. Plowman and W. F. Dearden. Pp. 127. (London: T. Fisher Unwin, Ltd.) is. net.
Fungoid Diseases of Farm and Garden Crops. By Dr. T. Milburn. Pp. xi+118. (London: Longmans and Co.) 25. net.
Alcoholometric Tables. By Sir E. Thorpe. xiv+91. (London: Longmans and Co.) 3s. 6d. net. British Museum (Natural History). British Antarctic (Terra Nova) Expedition, 1910. Natural History Report. Zoology. Vol. ii., No. 5. Nemertinea. By H. A. Baylis. Pp. 113-134+2 plates. (London: Longmans and Co,, and others.) 2s. 6d.
Catalogue of the Mesozoic Plants in the British Museum (Natural History). Part vi. The Cretaceous Flora. Part ii. Lower Greensand (Aptian) Plants of Britain. By Dr. Marie C. Stopes. Pp. xxxvi +360+ xxxii plates. (London: Longmans and Co., and others.) 21s.
THURSDAY, AUGUST 12, 1915.
THE PROBLEMS OF SCIENCE.
Problems of Science. By Prof. F. Enriques. Authorised Translation by K. Royce. Pp. xvi+392. (Chicago and London: The Open Court Publishing Co., 1914.) Price 10s. net.
ESIDES two introductory chapters of a more or less metaphysical kind, this work contains four others dealing respectively with logic, geometry, mechanics, and the extension of mechanics; the last concluding with a section on the phenomena of life. This range of subjects is so great that, as might be expected, the treatment of them is unequal; but the fact that they are all discussed by a mathematician is significant, and for at least two of the main topics (geometry and physics) the author's special knowledge is of great value.
Naturally, a reader will be inclined to attach most weight to the section on geometry; in some respects he will be right. In this domain Prof. Enriques is a leading authority, and a leading authority, and as he is treating of a subject with which he is thoroughly familiar, the result is very lucid and informing. We have a valuable historical account of the development of geometrical concepts, culminating with projective geometry in its modern form, and the different non-Euclidean theories, including the non-Archimedean geometry of Veronese; a good discussion of postulates; and a certain amount of psychological criticism, which is of a more controversial kind. One remark may be noticed as being (in English, at any rate) rather misleading. Before discussing Veronese's geometry, the author says:-"In the preceding examples the postulates that correspond to the various geometries express different physical hypotheses." As it stands, this is incorrect; any geometry, as such, is independent of physics altogether. What is probably meant is that each of the three Archimedean geometries is conceivably admissible as the "real" geometry most suitable for the physicist to assume in constructing his hypotheses. For instance, certain observations might make it simpler to assume a Riemann geometry than to modify the laws of motion. There is, on the other hand, no possibility of detecting by observation the existence of a non-Archimedean space, and there does not seem to be any possible development of physics which would naturally require the assumption of such a space.
and physical time which is likely to be really valuable, if used with the proper reservations; and he makes several useful remarks which illustrate the difference between a mathematician and and an unmathematical metaphysician. For instance, it is pointed out that "the notion of before and after does not furnish any criterion for comparing two intervals of time which have not a common beginning (or end) "-or, we may add, are derived from a succession A, B, C, D, which involves that BC<AD. For instance, yesterday and to-day together are longer than to-day; but from this we cannot infer anything about the length of to-day as compared with that of yesterday. The importance of having a clear concept of time has been recently emphasised by the theory of relativity (discussed pp. 349-63), and hypotheses in elasticity and thermodynamics where the influence of "heredity" is assumed (pp. 316-17).
The sections on physics are very interesting, and, so far as we can judge, give a sound and clear view of its main principles, as at present understood. The author's general attitude is stated on p. 366 in a passage too long to print here. Briefly, it is that in any physical science we form a set of concepts and hypotheses by abstraction from a set of experiments; we thus have a provisional "scheme of relations" which we test by more refined experiments. The latter may refute one or more of our hypotheses; as a matter of fact, the more usual result nowadays, at least in physics, is to suggest corrections or modifications in our formulæ, by which they become more concordant with the results of observation. This summary, of course, does not do justice to the author; it is in the way he shows historically how these tendencies have been at work that one great merit of his work consists. In this respect he may be compared with Mach, by whom he has evidently been much influenced.
The section on biology might well have been omitted; the time has not come for making any such general statements about the principles of biology as we can make about those of mathematics and physics. We are glad to find, however, that on p. 201 he does protest (all too mildly) against some of the absurdities of the experimental psychologists, when they wander from their proper sphere. That Wundt, for instance, should attempt "to derive the planary structure of intuitive space from the fact that the arrangement of the bones is such as to favour rectilinear movement" is one of the most extraordinary examples of begging the question we have ever seen. As Prof. Enriques points out, (like Bergson) a distinction between psychological the arrangement of the bones is not in favour of
To us the most interesting part of the book is that which deals with time. The author makes