to him to depend on the difference between dry continental air, and damp winds from sea coasts.

November 15.-Mr. Gabb described the results attained in tabulating Miocene fossils from Santo Domingo. He described 217 extinct and 19 living species, the latter found on both sides of the barrier of Central America, which is capped by Miocene rocks. December 20.-Prof. Cope read a paper on the zoological regions of the earth, and especially those of North America, agreeing as to the first with Drs. Sclater and Wallace in the main, adopting the Australian, Neotropical, Ethiopian, Neoarctic, and Palæartic (including Palatropical of S. and W.), stating that all the southern continents present marked distinguishing characters. In North America he adopted the Pacific, Lower Californian, Sonoran, Central, Eastern, and Austroriparian, which in the main agreed with those of Baird, the last being the southern part of his eastern, as far north as the isothermal of 773 F. The subdivisions were the Floridan, Louisianian, and Texan; those of the eastern after Allen, Caro linian, Alleghanian, Canadian, and Hudsonian.-Prof. O. C. Marsh gave an account of his discoveries in the Rocky Moun. tains since 1870, which included the first American Chiroptera, Marsupials, low forms of Quadrumana, birds with biconcave vertebræ, and several species of a new order, Dinocerata allied to the Proboscidia, but with horns and canine teeth.

January 3.-Prof. P. Fraser read a paper on a hydraulic problem, near Bethlehem Penna.

CALIFORNIA

Academy of Sciences, Dec. 18, 1872. "On the Parasites of the Cetaceans of the N.W. coast of America, with Descriptions of new Forms," by W. H. Dall, U. S. Coast Survey. Among the parasites most widely known as infecting the Cetacea, two classes may be recognised, viz., those which are true parasites, deriving their subsistence from the animal upon which they are found, such as the Pycnogonoids and Cyami, and those which are merely sessile upon the animal, and derive no nourishment or other benefit from it which might not equally well be furnished by an inanimate object, such as the various cirripedes.

VIENNA

I. R. Geological Institute, Jan. 21.-"Fossil Remains of Sirenoidæ found in the Venetian Territory," by Ach. Barone de Zigno. Besides the ribs and other bones of Halitherium which had been discovered many years ago in the upper tertiary beds of the Venetian Alps, the author succeeded in gathering a very rich collection of different species of Sirenoida in the lower tertiary beds (with Serpula spirulæa) of the Monte Zuello, near Montecchio, and in the glauconitic limestone of the basin of Belluno. The glauconitic strata of this basin had been taken till now for Eocene; but fossils found therein by Jaramelli -as Clypeaster placenta Des., Scutella, Subrotunda Lam, &c. -prove that they are of Miocene age.-"On the Eruptive Rocks of Styria," by R. von Drasche. The author gives an accurate petrographical analysis of the different eruptive rocks of Southern Styria, which by former observers had been taken for older porphyries, but which M. Stur has proved to be of tertiary age. They are andesites and trachytes. Some of these rocks resemble indeed very much older porphyries, and prove again the difficulty of discerning by mere petrographical or chemical properties eruptive rocks of different geological age.A. Redlenbacher presented a memoir on the Cephalopods of the Gosau-strata of the Alps. Since the last publications on this matter by Fr. von Hauer, the number of species in our collections has more than doubled. Only eight of them are identical with species out of non-Alpine cretaceous strata, and they belong all to Senonian beds.

and Carpathian sandstone) and are probably of Eocene age. In the highest parts of the valley, in the environs of Boli and Ferriere, the macigno is traversed by numerous masses and dykes of an eruptive rock which is partly gabbro, consisting of large crystals of amphibol and feldspar, and partly serpentine. These eruptive rocks are of a more recent age than the macigno, which is very much altered by contact with them. Partly in the eruptive rocks and partly in the adjacent altered macigno are to be found masses of copper- and iron-pyrites, and of magnetic iron ores; they form boulders of some size, but nowhere regular layers or veins. The mines which have been opened to gain these ores, M. Foetterle thinks, promise no great success. O. Feistmantel on the relations between the carboniferous and the Permian formations in Bohemia. In some of the Bohemian coal-basins, e.g. that of Radowenz at the foot of the Riesengebirge, in the north-western environs of Prague, in the basin of Pilsen, &c., two layers of coal are known, both accompanied by vegetable remains of a pure carboniferous type; but the strata between these layers contain remains of fishes, as Xenacanthus, Acanthodes, Palæoniscus, &c., which belong to the Permian fauna. The author concludes that the upper coal layers of the Bohemian coal-basins belong to the Permian formation, and the lower only to the carboniferous formation, and that both formations are most intimately allied by their identical flora.

LONDON INSTITUTION, at 4.- Elementary Botany: Prof. Bentley. GEOLOGISTS' ASSOCIATION, at 8 -Visit to Museum of Practical Geology. TUESDAY, APRIL 22.

ROYAL INSTITUTION, at 3 - Music of the Drama: Mr. Dannreuther. INSTITUTION OF CIVIL ENGINEERS, at 8.-Discussion on Mr. Head's paper on Steam Locomotion on Common Roads-On the Delta of the Danube, and the Provisional Works erected at the Sulina Mouth.-Sir C. A. Hartley.

ANTHROPOLOGICAL SOCIETY, at 8.-Religious Beliefs of Ojibois or Santeux Indians resident in Manitoba and at Lake Winnepeg: A. P. Reid, M. D.Danish aspect of the Nomenclature o Cleveland: Kev. J. C. Atkinson.Rock Inscriptions in Brazil: John Whitfield.

WEDNESDAY, APRIL 23.

LONDON INSTITUTION, at 7.-On some Phenomena connected with Magnetism: W. F. Barrett.

SOCIETY OF ARTS, at 8.-On Silk-Worm Grain: M. Alfred Roland.
ARCHEOLOGICAL A SOCIATION, at 8.

SO IETY OF ANT QUAKIES, at 8.30.-Anniversary.

ROYAL SOCIETY OF LITERATUKE, at 8. 30.-1 he Serio Comic Satirical Poetry
of the 18th and 19th centuries: Sir Patrick de Colquhoun, Q.C., LL.D.
SOCIETY OF TELEGRAPH ENGINEERS, at 7.30.-On the block System of
Working Railways: W. H. Preece and Capt. Mallock.
THURSDAY, APRIL 24.

ROYAL INSTITUTION, at 3.-Light: Prof. Tyndall.
ROYAL SOCIETY, at 8.30.

OUR BOOK SHELF.

LETTERS TO THE EDITOR: -

CONTENTS

Cave Deposits of Borneo.-A. R. WALLACE and A. EVERETT
A Fact for Mr. Darwin.-H. D. MAS Y

The Phoenician Vademecum.-HYDE CLARKE
Earthquake Waves.-HYDE CLARKE
Spectrum of Aurora.-T. W. BACKHOUSE
Spec rum of Nitrogen.-C. H. STEARN.
Instinct -HENRY FORDE.

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462

462

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463

463

Indices of Journals.-Dr. Jo-N YOUNG.

Destruction of Rare Birds: White Tom Cats Phosphorescence in Wood.-RICHARD M BARRINGTON

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THE DUTCH SOCIETY OF SCIENCES.

PHYSICO-CHEMICAL RESEARCHES ON THE AQUATIC ARTICULATA. By

ON AN AIR-BATTERY.

By Dr. J. H. GLADSTONE, F.R.S., and ALFRED TRIBE, F.R.S. (With Illustration). SCIENTIFIC SERIALS

SOCIETIES AND ACADEMIES

THURSDAY, APRIL 24, 1873

SCIENTIFIC ENDOWMENTS AND BEQUESTS S

OME weeks ago we published the notice issued by Trinity College, Cambridge, respecting a Fellowship offered by that corporation for Natural Science, in which Zoology is one of the subjects by which it may be obtained. Candidates are required to send to the electors "any papers which they may have published containing original observations, or experiments, or discussions of scientific questions, or any similar matter in manuscript," and they will be liable to be examined in the subjects of their papers and in subjects connected with them, or in the branch of science to which they refer."

66

A fortnight ago, a New York correspondent gave us the details of a munificent bequest made by Mr. John Anderson, a wealthy merchant of that city, to Prof. Agassiz, and through him to the University of Cambridge, Massachusetts, of Penikese Island, situated about 170 miles east by north of New York, and 12 miles south of Boston, on the New England coast, as a station for the study of Practical Zoology, mainly marine. Finding that pecuniary aid was also absolutely necessary to put the whole in working order, Mr. Anderson, with a liberality almost unprecedented, put 50,000 dollars at Prof. Agassiz's disposal, as a nucleus for a permanent endowment fund" in the formation of his Marine Naturalists' School.

The above-cited cases are two of the most important steps that have been taken of late to advance the thorough study of zoology either in England or America, but the method employed by the one to arrive at this result is so different from that adopted by the other, that the question may well be asked, which of the two in the long run will produce the most satisfactory results? Is it better, as done by Trinity College, to offer considerable and substantial rewards to students of promise, or, as in the case of Mr. Anderson's gift, to simply place undoubtedly great facilities in the way of untried beginners on the subject?

Notwithstanding the extreme liberality shown by Mr. Anderson in his bequest, we cannot help feeling that most of the previous attempts that have been made to advance science by providing increased facilities for work, without at the same time improving the general prospect of a sufficient livelihood for those who devote the whole or the most of their time to it, have met with but little success; and perhaps there is nothing more disappointing to those who are anxious for the progress of the subject, to see the way in which establishments excellently planned at great cost, are often almost at a standstill for want of their most important element pupils. Such a method of procedure, if numbers are obtained, is likely but to produce an assemblage of amateur students, whose work, as it must be from the lack of sufficient stimulus to great mental effort, is poor from its want of thoroughness, and therefore comparatively useless in the long run, only encumbering the subject and leading lookers-on to suppose, from the few results arrived at, that the science is not worthy of deeper consideration. No. 182-VOL. VII.

Zoology and Biology generally have suffered much already from such kind of work.

The tendency of all observation as to the origin and development of the sciences which are now firmly established, is to prove quite clearly that what was required in each of them to give it a start, and make it continue to advance rapidly, was that it should have a practical bearing of some kind or another. There cannot be the least doubt that the rapid advances which have occurred in the study of electricity, and the large number of valuable discoveries and important laws that have been found out concerning it, are but the expression of the mercantile value of the telegraph system as it now exists; the forensic and manufacturing importance of chemistry has in great measure raised it to the important position it now holds; and the money voted for the observations of the transit of Venus is indirectly connected with the importance of astronomical observation in facilitating navigation. But it is not at all easy to show clearly that there are any direct practical results to be arrived at from the study of zoology; the knowledge of the facts that our relationship with the higher apes is more intimate than has been till lately supposed, and that we must consider an Ascidian as the Noah of our zoological pedigree, may be of interest to many as curious results, but they do not lead to or suggest fresh methods of action on the part of anyone, and cannot otherwise be made profitable. Consequently other means must be employed to cause the science to progress in a manner which does credit to the large number of new facts which are continually being brought forward, and the method adopted by Trinity College is one which promises the best results. That the prospect of a Fellowship is a strong inducement to work is undisputed, and what all biologists would like to see, is a little more willingness on the part of other colleges in both Universities, to give them to deserving students of the subject. Some profess to place natural science on the same footing as the other University final examinations, with regard to pecuniary rewards, but it is very seldom, scarcely ever indeed, that we have the opportunity of recording in our columns any elections to natural science fellowships. As long as classics hold the position that they do-one maintained only by the funds and appointments which, but from an excessive and short-sighted conservatism, would have been in great measure diffused in other directions long before now, no complaint can be made of the comparatively non-practical bearing of zoology and comparative anatomy; for though classics may be a good mental training, so is the latter, and the study of the former has certainly not a more practical bearing.

The principle on which the election to the New Trinity Fellowship is to be conducted, is evidently the result of mature consideration and experience, partly no doubt arrived at after the unsuccessful experiment in the same direction a little more than two years ago, in which it was made too evident that a simple examination on the subject could not ensure the discovery of a genuine Zoologist. A much more successful result may be anticipated from the new system of election, for it is difficult to believe that any candidate, who at the time of election has completed sufficient good work to satisfy the electors, can possibly, on account of its intrinsic

DD

interest when he has arrived so far, give up the further pursuit of scientific work. When the governors of any institution can bring men up to this point, and can then supply them with the necessary means, they may consider that their work is finished.

CLERK-MAXWELL'S ELECTRICITY AND

MAGNETISM

A Treatise on Electricity and Magnetism. By James Clerk-Maxwell, M.A., F.R.S., Professor of Experimental Physics in the University of Cambridge. (Clarendon Press Series, Macmillan & Co., 1873.)

IN

N his deservedly celebrated treatise on "Sound," the late Sir John Herschel felt himself justified in saying, "It is vain to conceal the melancholy truth. We are fast dropping behind. In Mathematics we have long since drawn the rein and given over a hopeless race." Thanks to Herschel himself, and others, the reproach, if perhaps then just, did not long remain so. Even in pure mathematics, a subject which till lately has not been much attended to in Britain, except by a few scattered specialists, we stand at this moment at the very least on a par with the élite of the enormously disproportionate remainder of the world. The discoveries of Boole and Hamilton, of Cayley and Sylvester, extend into limitless regions of abstract thought, of which they are as yet the sole explorers. In applied mathematics no living men stand higher than Adams, Stokes, and W. Thomson. Any one of these names alone would assure our position in the face of the world as regards triumphs already won in the grandest struggles of the human intellect. But the men of the next generation-the successors of these long-proved knights-are beginning to win their spurs, and among them there is none of greater promise than Clerk- Maxwell. He has already, as the first holder of the new chair of Experimental Science in Cambridge, given the post a name which requires only the stamp of antiquity to raise it almost to the level of that of Newton. And among the numerous services he has done to science, even taking account of his exceedingly remarkable treatise on "Heat," the present volumes must be regarded as pre-eminent.

We meet with three sharply-defined classes of writers on scientific subjects (and the classification extends to all such subjects, whether mathematical or not). There are, of course, various less-defined classes, occupying intermediate positions.

First, and most easily disposed of, are the men of calm, serene, Olympian self-consciousness of power, those upon whom argument produces no effect, and whose grandeur cannot stoop to the degradation of experiment! These are the a priori reasoners, the metaphysicians, and the Paradoxers of De Morgan.

Then there is the large class, of comparatively modern growth, with a certain amount of knowledge and ability, diluted copiously with self-esteem-haunted, however, by a dim consciousness that they are only popularly famous -and consequently straining every nerve to keep themselves in the focus of the public gaze. These, also, are usually, men of "paper" science, kid-gloved and blackcoated-with no speck but of ink.

Finally, the man of real power, though (to all seeming) perfectly unconscious of it-who goes straight to his

mark with irresistible force, but neither fuss nor hurry— reminding one of some gigantic but noiseless "crocodile," or punching engine, rather than of a mere human being.

The treatise we have undertaken to review shows us, from the very first pages, that it is the work of a typical specimen of the third of these classes. Nothing is asserted without the reasons for its reception as truth being fully supplied-there is no parade of the immense value of even the really great steps the author has made-no attempt at sensational writing when a difficulty has to be met; when necessary, there is a plain confession of ignorance without the too common accompaniment of a sickening mock-modesty. We could easily point to whole treatises (some of them in many volumes) still accepted as standard works, in which there is not (throughout) a tithe of the originality or exhaustiveness to be found in any one of Maxwell's chapters.

The main object of the work, besides teaching the experimental facts of electricity and magnetism, is everywhere clearly indicated-it is simply to upset completely the notion of action at a distance. Everyone knows, or at least ought to know, that Newton considered that no one who was capable of reasoning at all on physical subjects could admit such an absurdity: and that he very vigorously expressed this opinion. The same negation appears prominently as the guiding consideration in the whole of Faraday's splendid electrical researches, to which Maxwell throughout his work expresses his great obligations. The ordinary form of statement of Newton's law of gravitation seems directly to imply this action at a distance; and thus it was natural that Coulomb, in stating

his experimental results as to the laws of electric and magnetic action which he discovered, as well as Ampère in describing those of his electro-dynamic action, should state them in a form as nearly as possible analogous to that commonly employed for gravitation.

The researches of Poisson, Gauss, &c., contributed to strengthen the tendency to such modes of representing the phenomena; and this tendency may be said to have culminated with the exceedingly remarkable theory of electric action proposed by Weber.

All these very splendid investigations were, however, rapidly leading philosophers away towards what we cannot possibly admit to be even a bare representation of the truth. It is mainly to Faraday and W. Thomson that we owe our recall to more physically sound, and mathematically more complex, at least, if not more beautiful, representations. The analogy pointed out by Thomson between a stationary distribution of temperature in a conducting solid, and a statical distribution of electric potential in a non-conductor, showed at once how results absolutely identical in law and in numerical relations,

could be deduced alike from the assumed distance-action of electric particles, and from the contact-passage of heat from element to element of the same conductor.

But we must give Maxwell's own frank and ample acknowledgment of his debt to these two men.

"The general complexion of the treatise differs considerably from that of several excellent electrical works, published, most of them, in Germany, and it may appear that scant justice is done to the speculations of several eminent electricians and mathematicians. One reason of this is that before I began the study of electricity I resolved to read no mathematics on the subject till I had

first read through Faraday's 'Experimental Researches on Electricity.' I was aware that there was supposed to be a difference between Faraday's way of conceiving phenomena and that of the mathematicians, so that neither he nor they were satisfied with each other's language. I had also the conviction that this discrepancy did not arise from either party being_wrong. I was first convinced of this by Sir William Thomson, to whose advice and assistance, as well as to his published papers, I owe most of what I have learned on the subject.

"As I proceeded with the study of Faraday, I perceived that his method of conceiving the phenomena was also a mathematical one, though not exhibited in the conventional form of mathematical symbols. I also found that these methods were capable of being expressed in the ordinary mathematical forms, and thus compared with those of the professed mathematicians.

"For instance, Faraday, in his mind's eye, saw lines of force traversing all space where the mathematicians saw centres of force attracting at a distance: Faraday saw a medium where they saw nothing but distance: Faraday sought the seat of the phenomena in real actions going on in the medium, they were satisfied that they had found it in a power of action at a distance impressed on the electric fluids."

It certainly appears, at least at first sight, and in comparison with the excessively simple distance action, a very formidable problem indeed to investigate the laws of the propagation of electric or magnetic disturbance in a medium. And Maxwell did not soon, or easily, arrive at the solution he now gives us. It is well-nigh twenty years since he first gave to the Cambridge Philosophical Society his paper on Faraday's Lines of Force, in which he used (instead of Thomson's heat-analogy) the analogy of an imaginary incompressible liquid, without either inertia or internal friction, subject, however, to friction against space, and to creation and annihilation at certain sources and sinks. The velocity-potential in such an imaginary fluid is subject to exactly the same conditions as the temperature in a conducting solid, or the potential in space outside an electrified system. In fact the socalled equation of continuity coincides in form with what is usually called Laplace's equation. In this paper Maxwell gave, we believe for the first time, the mathematical expression of Faraday's Electro-tonic state, and greatly simplified the solution of many important electrical problems. Since that time he has been gradually developing a still firmer hold of the subject, and he now gives us, in a carefully methodised form, the results of his long-continued study.

A sentence like the following has a most cheering effect when we meet with it in a preface; and we need only add that our author has been thoroughly successful in the endeavour he promised

"I shall avoid, as much as I can, those questions which, though they have elicited the skill of mathematicians, have not enlarged our knowledge of science."

He might with truth, and with propriety, have added that he would also avoid, as far as possible, those socalled experimental illustrations which require in the operator training akin to that of a juggler, and which are calculated to mystify, and to retard the progress of, the real student, while gratifying none but the mere gaping sight-seer.

It is quite impossible in such a brief notice as this to enumerate more than a very few of the many grand and

valuable additions to our knowledge which these volumes contain. Their author has, as it were, flown at everything;-and, with immense spread of wing and power of beak, he has hunted down his victims in all quarters, and from each has extracted something new and invigorating -for the intellectual nourishment of us, his readers.

The following points, however, appear to us to be especially (we had almost said exceptionally) worthy of notice :

1. Though not employing the Quaternion Calculus, Maxwell recognises its exceeding usefulness in exhibiting (merely by the extraordinary simplicity and comprehensiveness of its notation) the mutual relations of various di

rected, or vector, quantities; together with their derivation from scalar quantities, such as potentials, by the use of the Hamiltonian V, the operator whose square is the negative of the scalar operator in Laplace's equation. There can be little doubt that in this direction must lie the next grand simplification of the somewhat complex mathematics of electro-dynamic investigations.

2. The notion of electric Inertia, first clearly pointed out by Helmholtz and Thomson, is here developed in a most splendid style. The mechanism whose inertia has to be overcome before a steady current of electricity can be started or stopped in a conductor, and which opposes a resistance exactly analogous to the inertia equivalent of an ordinary train of wheels, is treated by means of the general equations of motion in the forms given respec tively by Lagrange and by Hamilton. Maxwell has adopted from Thomson and Tait's "Natural Philosophy" the idea of commencing with the impulse required to produce a given motion of a system, and has developed in this way the general equations in a form suitable for electric problems where the mechanism is as yet entirely unknown.

3. The chapter dealing with Electrolysis we may specially refer to, as containing, not merely an admirable summary of what was previously known but also, several new ideas apparently of great value.

4. Another curius feature of the work is the amount of labour bestowed upon the exceedingly userul, but dry and uninteresting, pursuit of accuracy in the tracing of the forms of Lines of Force and determinations of strengths of electric and electro-magnetic fieids, and their deviation from uniformity under various conditions, some or excessive complexity. For the theory of the newer instruments, especially Thomson's electrometers and galvanometers, and also for their applicability to problems in quite different branches of physics, these results are very valuable.

5. Another feature in which this differs from all but a very few of the very best scientific works is the particular care bestowed upon the modes of measurement, the units employed, and the Dimensions (in terms of these units) of the various quantities treated of-such as, for instance, Electric Quantity, Electric Potential, Electric Current, Electric Displacement, &c.

6. The subject of Electric Images is developed at considerable length, and the reader is led up by easy steps to a sketch of the grand problem which, though solved in simple finite terms a quarter of a century ago by Thomson, has remained unnoticed till very recently, viz., the statical distribution of electricity upon a spherical bowl.