continuity. This conclusion is opposed to Riemann's theory. H. Weber, in his recent edition of Riemann's "Vorlesungen über die partiellen Differentialgleichungen der mathematischen Physik," has contended that a complete calculation of the energy supports Riemann's theory against Lord Rayleigh's objection, but he did not refer to Hugoniot. In the book under review no mention is made of Lord Rayleigh's objection or of H. Weber's contention, but Riemann's theory and Hugoniot's are developed side by side, and the results are compared both with each other and with the results of certain experiments by Vieille. Much of the analysis is worked out and interpreted by the aid of geometrical constructions, but the reader wishes often for a more physical interpretation.

Chapters v. and vi. contain extensions of the theories of the preceding chapters to motion in three dimensions and to waves in elastic solid media. The physical value of a theory of rapid motions, accompanied by strains that are not "small," in an elastic solid, supposed to have a strain-energy function, is extremely doubtful; but no exception can be taken to the analytical methods by which the theory is developed. Chapter vii. brings the theory of waves that do not involve discontinuities of velocity or strain into relation with the theory of characteristics of partial differential equations. The discovery of the relations between these two theories has attracted a good deal of attention recently, and we may be grateful to M. Hadamard for his masterly exposition of the subject. A few notes are appended to the volume. Of these the most interesting is the one in which it is shown that discontinuities of the first order may give rise to vortex motion, even when the pressure and density in the undisturbed state are uniform throughout the fluid.

It is a sign of the healthy state of mathematics in France that the ablest analysts are bringing their powerful methods to bear upon recondite physical questions. The book under notice is a very valuable contribution to a most important and, at the same time, a most difficult subject. It breaks fresh ground, and it cannot fail to stimulate inquiry. It may be expected to conduce to the further advance of our knowledge of aerodynamics. A. E. H. L.

THE GREAT ST. BERNARD PASS. Across the Great St. Bernard. The Modes of Nature and the Manners of Man. By A. R. Sennett. Pp. xvi+444 and 111; illustrated. (London: Bemrose and Sons, 1904.)

A

FLUENT but not too accurate pen, and a general knowledge of the more frequented districts of the Alps appear to be Mr. A. R. Sennett's chief qualifications for writing this book. It has a comprehensive title, and needs it, for the St. Bernard Pass is hardly more than a thread to connect, if possible, quotations in prose and verse, scraps of science and history, descriptions of scenery, and moralisings on things in general. The author has nothing new to tell us about the St. Bernard, which is not surprising, for the pass has been often described, and a carriage road now goes the whole way from Martigny

to Aosta. Mr. Sennett, however, informs us that Hannibal crossed it "with his vast army," of which he proceeds to describe the sufferings. Notwithstanding what has been written by Law, Ellis, Freshfield and others, we are well aware that it is not easy to determine what route Hannibal did follow, but thought that the Great St. Bernard was no longer advocated by anyone who had studied the question.

"its

Other statements are disputable. We are told the soldanella flower protrudes through the edge of the névé (which does not mean the winter snow); that the edelweiss dwells "in snow, owning a habitat where no other flowering plant may survive," and as haunt is far removed from all verdant vegetation and in the most craggy and inaccessible positions," we cannot expect to see it growing at the botanical station in Bourg St. Pierre, and so forth. This village is rather more than 5300 feet above sea-level, and the plant is often found between this and 6000 feet; indeed, it can be cultivated in England. As for the craggy and inaccessible positions, we had thought newspaper correspondents now enjoyed a monopoly of this fiction. Like any other Alpine plant, it may grow in a breakneck place, but its favourite habitat is a rough slope of grass and stone. It used to grow profusely on a place of this kind, where it could be gathered in perfect safety, on a mountain ridge about a thousand feet above San Bernardino.

But Mr. Sennett, though prone to discuss scientific questions, does not always win our confidence. The "Tertiary period of the London Clay" is an odd phrase, and adamantine an inappropriate epithet for the firm or upper basin of a glacier; and in what respect the Lago di Garda resembles a diadem we fail to perceive. To his vision of a Europe the glacier fields of which only just failed in reaching the Alps we are perhaps accustomed, but think that most geologists at the present day would speak less confidently of glaciers having scooped out the Alpine lake basins, or having "cut out gorges for themselves through the solid mountain, divided enormous peaks in twain, planed down and levelled great asperities." The Märjelen See does not lie in a lake basin, but simply at the head of a glen, blocked by the great Aletsch Glacier, and after seeing it one day full and the next empty, we utterly disbelieve Mr. Sennett's explanation that it is emptied on the principle of a syphon. The name Mörjelen, which he prefers, may be patois, but the other form is more usual; so also is Gondo for Gonda, Guttannen for Guttenen, Meiringen for Meyrengen, and, notwithstanding Baedeker, Penninus for Pœninus (the title of the Alpine Jupiter). The science is discursive and commonplace, where not enriched by extracts from Tyndall or Ruskin, or yet more ornamental writing. Mr. Sennett may think in English, but is SO prone to translate into journalese that we suspect he was trained in a certain Fleet Street haunt of young lions. We cannot welcome the verb ' resurrect," the adjective " riverian " (of or belonging to a river), or "lithic " (a favourite one) when plain folks would say stony or rocky. The book, however, contains numerous illustrations, often pretty, but it is tiresome to have them (except in the appendix) only

66

numbered, and to be obliged to consult a list to see what they are, especially when we are sometimes greeted with fanciful titles instead of place-names. "Dame Nature's Painters" does not much enlighten us, but it looks very like a view down the lower part of the Via Mala. But the author has tried the dangerous experiment of mingling poetry and science, and we cannot honestly congratulate him on his success.

DR.

TRACHOMA.

66

T. G. B.

Trachoma. By Dr. J. Boldt. Translated by J. Herbert Parsons, D.Sc., F.R.C.S., and Thomas Snowball, M.B., C.M. With an introductory chapter by E. Treacher Collins, F.R.C.S. Pp. lii+ 232. (London: Hodder and Stoughton, 1904.) R. BOLDT'S monograph on Trachoma," published at the end of last year, deals with a subject presenting many problems to which no satisfactory solutions can at present be offered. It is therefore a matter for congratulation that an English translation of such an excellent résumé of the subject has been prepared. Dr. Boldt has been working for many years in one of the trachoma infested centres of Germany,

and has been constantly faced during that time with these unsolved problems, and in the book before us he clears the ground of all the lumber which gathers round any subject of discussion, and states clearly the present condition of our knowledge and the lines on which future investigation must go.

The first and most important difficulty met in dealing with trachoma is that at present the etiological factor is unknown. The discussion of this question in chapter iv. particularly, and incidentally in chapters iii. and v., will be, to ophthalmic surgeons, the most interesting part of the book. The author distinctly inclines to the view that there is a specific organism, the primary cause of trachoma, as yet undiscovered, but that also an individual predisposition and a number of subsidiary causes, such as climate, soil and race, overcrowding, uncleanliness, and other social evils, are also contributing causes.

Many workers at the present time are inclining to lay much greater stress on the importance of the individual predisposition and to hold the view that the disease may be set up by any bacterium which is pathogenic for the conjunctiva. The large number of cases in which some scrofulous taint can be traced is dis

tinctly in favour of this view. It has been frequently shown that in such people any infection will give rise to a lymphoid hypertrophy, and the essential pathology of trachoma is primarily a hypertrophy of lymphoid follicles with subsequent degeneration of the lymphoid tissue and formation of scar tissue. Dr. Boldt, with absolute fairness, gives both hypotheses and the arguments which have been advanced by various writers in support of them.

It would be of undoubted benefit to the community if this book were to get into the hands of two classes in particular, the men who are concerned in the administration of the Poor Laws of the country, and those concerned in the medical and sanitary administration of

the Army. The excellent introductory chapter by Mr. Treacher Collins gives details of the most useful work which is being carried on at Swanley, and of the influence that proper hygienic measures have had generally in checking the disease. Dr. Boldt gives similar details of the progress and subsequent checking of trachoma throughout the various countries of Europe. It would indeed be well if the last chapter were separately printed and distributed as a pamphlet to the various boards of guardians and health officers throughout the Empire.

We have nothing but praise for the way in which the translators have carried out their work. We could nowhere detect a trace of German origin in the style.

OUR BOOK SHELF.

The Cyclones of the Far East. By Rev. José Algué, S.J. Second (Revised) Edition. Pp. 283. (Manila: Bureau of Public Printing, 1904.)

IN the present edition the author has extended the area dealt with in the earlier editions, and as abundant additional data have been collected, not only from the

Philippines themselves, but also from the surrounding

changed from

The

coasts, this information has now been embodied. author says that, "owing to the opening up of the Far East in recent years, an endeavour has been made to extend the usefulness of the work by giving a greater compass to the study of the phenomena which cause, accompany, and follow the atmospheric perturbances which are experienced in the various seas of the Far East." The title of the revised edition is Cyclones of the Philippines" to "The Cyclones of the Far East." The present edition appears in English, and is freed from the formidable list of errors found in the English version of an earlier edition. Among the many additions contained in this for navigating in case of encountering a typhoon, and new edition may be mentioned some practical rules a list and description of the ports of refuge during storms in the Far East, especially in the Philippine Archipelago.

Commendation should certainly be given of the careful arrangement and division of the whole work, which aid much the general study and grip of the valuable material, whilst numerous illustrations add much to the elucidation of the subject. Father Algué must be credited with what is only too commonly overlooked. At the conclusion of each chapter reference is given to the works which may be consulted in connection with the branch of the subject dealt with. The references appear to have been chosen with the the work as complete as possible. This example may greatest impartiality and with the sole desire to render commend itself to authors of other branches of scientific work.

The principal cause which influences the progressive movement of typhoons is said to be the general movement of the atmosphere in which they take place, not of that part only which overlies the land and sea over which they pass, but especially of that portion of the atmosphere which moves at higher altitudes, as we are to look there for the seat of the greater part of the energy and power which nourish and sustain the atmospheric whirls. This opinion is endorsed by all who discuss the nature and law of storms, but,

unfortunately, too little light can be thrown on the movement of the upper air, although praiseworthy efforts are being made in this direction.

The storms which visit the Philippine Archipelago vary greatly in frequency according to season, the months with the greatest number being July, August, and September, whilst the months with the least frequency are January, February, and March. Much good work is done in the classification of cyclones, and diagrams are given showing the paths of eleven different types. Considerable attention is paid to the precursory signs of cyclones, and naturally much importance in this direction is attached to the form and movement of clouds.

The whole treatise is suggestive of further scientific inquiry, and Father Algué has done much by this work to advance our knowledge of the law of storms.

C. H.

The Animals of New Zealand: an Account of the Colony's Air-breathing Vertebrates. By F. W. Hutton and J. Drummond. Pp. xiv+381; illustrated. (Christchurch and London: Whitcombe and Tombs, Ltd., 1904.)

SOME months ago, when noticing Captain Hutton's valuable "Index of the New Zealand fauna, we had occasion to refer to the impending issue of the present volume; now that it is before us, we are happy to be able to state that it fully realises our expectations, and forms a most valuable history of the air-breathing vertebrates of the colony, written in a pleasant style which cannot fail to make it acceptable to a large circle of readers. At starting, the authors refer to their indebtedness to the late Mr. T. H. Potts, who did such good work in describing a fast vanishing fauna before it was too late. The melancholy story of the waning of this curious and interesting fauna forms, indeed, the key-note of the introduction of the volume. From the time that Captain Cook, in 1773, turned down pigs in Queen Charlotte's Sound, the native fauna has had to contend with competitors from Europe of a stronger and more aggressive type, the natural result being that many forms, like the tuatera lizard, have already disappeared from the mainland, although in some instances surviving in the adjacent islets, and many more are destined to go ere long. Among the latter (if, indeed, it be not already extinct) is the short-tailed bat, the sole representative of the genus Mystacops, its rarity, or extermination, being attributed to the destruction of insect life caused by the introduction of European birds.

From a purely commercial standpoint the authors do not, however, by any means condemn the introduction of many of the foreign species, having even a good word to say for the much abused sparrow. “Without the sparrow, or some other bird equally common," they write,"residents in the colony would be over-run with the insects again, and life would be insupportable. The phrase concerning insects, it may be explained, refers to the "plagues" of various species which occurred when European food-crops were first introduced into the colony. On the other hand, the introduction of certain species, such as the greenfinch and, above all, the rabbit, is most strongly condemned. The acclimatisation of several kinds of deer is considered to be of considerable advantage to the general prosperity of the islands, as it leads to the visits of European sportsmen.

Among the species which have suffered most severely from foreign competition may be mentioned the two bats, the kiwis, the weka rail, and the tuatera. The moas appear to have been completely and the Notornis all but exterminated by the Maories before the European advent.

Limitations of space alone prevent further commendation of a very excellent, interesting, and beautifully illustrated work.

By Prof. Dr.

Zellenmechanik und Zellenleben.
Rhumbler. Pp. 43. (Leipzig: J. A. Barth, 1904.)
Price I mark.

THIS little work represents a sketch of the author's
views on the causes and means of manifestation
of cellular activity. The point of view adopted is a
materialistic one. It is considered that the whole
subject should be dealt with from the physical or the
physico-chemical aspect, even when this fails to present
a complete solution of all the difficulties that may arise.
It is becoming more and more recognised that many
of the acts which used to be regarded as specially the
outcome of vital activity find their parallel in inorganic
nature. An amoeba when ingesting a filament of
oscillatoria much longer than itself is able com-
pletely to enclose it because the algal thread becomes
coiled up within the protoplasmic body of the proto-
zoan. But an exactly similar state of things is pro-
duced if a drop of chloroform is placed in water and
a filament of shellac be then presented to it. The fila-
ment is drawn into the chloroform, and coiled up much
as the alga in the amoeba; and if a short glass thread
be coated with shellac, it is also "ingested,
" but as
the lac becomes dissolved the glass thread is
gradually extruded. The whole question here resolves
itself into one of surface tension, and perhaps the pro-
cesses of ingestion and excretion may ultimately prove
to be essentially similar in nature.

Again, the remarkable uniformity in the details of nuclear divisions (karyokinesis), from whatever source the cells may originate, strongly suggests that a comprehensive physical explanation of the process will one day be forthcoming.

But although the physical aspects of cellular activity will certainly become more clear and definite, this is only the first step on to the threshold of the temple in which the secret of life is guarded. Behind the proximate physical phenomena lies a vast complex of changing chemical conditions, and it will be long before we are likely to be able exhaustively to analyse them. The more successfully we do so, however, the more nearly shall we be able to grapple with the physical problems of movement and the like. Rhumbler regards changes of surface tension, and the reactions that affect it, as constituting one of the most profitable of the many possible lines of cytological investigation.

Studies in Astronomy. By J. Ellard Gore, F.R.A.S., M.R.I.A. Pp. xi+336. (London: Chatto and Windus, 1904.) Price 6s.

In this book the reader is presented with a series of disconnected essays on a variety of astronomical subjects, many of which include interesting and suggestive results of calculations made by the author. The subjects range from "giant telescopes "to the "construction of the visible universe," but Jupiter is the only planet to which any detailed reference is made, and the sun is only dealt with from the point of view of its stellar magnitude and its motion in space. The chapter on "Messier's nebulæ," bringing together all the recent information with regard to these objects, will be of considerable value to those who possess telescopes, and the notes comprising "recent advances in stellar astronomy give a useful summary of the state of our knowledge of the subjects dealt with at the beginning of the present year.

Most of the papers have already appeared as magazine articles, and, notwithstanding the revision which has been made for the present purpose, there is necessarily a considerable amount of repetition. Apart from this, however, the book provides a very acceptable course of not too difficult reading for those who have a general elementary acquaintance with the subject.

1904.) Price 3s. 6d. net.

THIS book is intended to serve as an introduction to the study of practical chemistry, and has for its basis a series of notes intended for use in the Edinburgh classes. In an interesting preface Prof. Crum Brown states his belief in the possibility of devising a course that would be "something better than a mechanical training to enable students to pass a mechanical examination consisting in the detection of simple salts in solution." Notwithstanding this assurance, one finds that about half the book consists of descriptions of the ordinary tests and schemes of analysis common to most books treating of elementary practical chemistry.

The first part of the work consists of a short and very clear account of the general physical properties of salts and salt solutions. An outline is given of the ionisation hypothesis and of its applications, some of which are practically illustrated at a later stage. After a short account of the nature and use of indicators, a chapter is devoted to alkalimetry and acidimetry. The experimental part of the book, excluding the sections on qualitative analysis, is only represented by about twenty-five pages, and although the selection of experiments has evidently been carefully made, it seems a pity that the practical illustration of a really excellent theoretical introduction should be so meagre.

The remainder of the book is taken up with a description of the reactions of metallic and salt radicals, and with schemes for analysis. In several small particulars a departure from the conventional methods has been made with distinct advantage. Dry-way reactions, which so few chemists appear to appreciate, are relegated to an appendix, which also contains the inevitable and perfectly useless description of the reactions of the so-called rare elements. Teachers who have the management of large practical classes should find the volume of value.

LETTERS TO THE EDITOR.

[The Editor does not hold himself responsible for opinions expressed by his correspondents. Neither can he undertake to return, or to correspond with the writers of, rejected manuscripts intended for this or any other part of NATURE. No notice is taken of anonymous communications.]

Radiation Pressure.

ON p. 515 of your issue of September 22 I stated that there is a retarding force on the earth as it moves along its orbit amounting in all to about 20 kgm. The calculation was made on the supposition that the earth is a full radiator of uniform temperature. I have found on revising the calculation that there was an error in the arithmetic, and that the force is considerably greater, though still too small to have an effect worth considering. The following is a simple method of obtaining its value. It assumes that the earth may be treated as a black sphere exposed to sunlight, radiating as much as it receives, and with all its surface at one temperature.

on

If the stream of solar energy falling normally I sq. cm. is S per second, a black sphere, radius a, receives a S per second. If it radiates R per second per sq. cm. its total radiation is 4a2R, and the assumption of equal receipt and expenditure gives RS/4. The total repulsive force exerted by the sun's radiation is STа2/U, where U is the velocity of light. The total retarding force due to velocity u in the orbit is 4/3 Ru/U2.a. This is the Doppler effect due to crowding of energy in front and open

At the earth's distance u/U is about 10-', so that the retarding force is about 1/30,000 of the solar repulsion.

If we take S/U as 5.8 × 10-3 dyne/sq. cm. (Phil. Trans., loc. cit., p. 539), and the radius of the earth as 6.37 × 108 cm., the total solar about repulsion is 75×10° kgm., say 75,000 tons, and the retarding force is about 2500 kgm.

But another effect comes in which will more than counterbalance this. The hemisphere of the earth which is advancing in the orbit is on the whole colder than that which is retreating, owing to the lag in the warming of the surface exposed to the sun. I find that if one hemisphere is at 301° A. and the other at 300° A., the greater radiation from the warmer side gives a net push directed from that side to the colder of about 165,000 kgm. Of course this hemispherical distribution of temperature is only a rough approximation to the real condition, and even if the force be as large as 165,000 kgm. only a component of it acts along the orbit tending to accelerate the motion. Still, that component must almost certainly be much greater than the retarding force due to the Doppler effect, and on the whole, therefore, there is probably a small acceleration in the orbit. A force of 2500 kgm. would destroy about 4/101 of the earth's momentum in one year. Even if the accelerating force were twenty-five times as great as this it would only generate 1/101 of the present momentum in one year. This illustrates the insignificance of radiation pressure on the larger bodies in the solar system.

I take this opportunity of correcting another error in the address in NATURE of September 22, which has been pointed out to me by Mr. C. T. Whitmell. It arose from some very faulty arithmetic on p. 541 of the paper in the Philosophical Transactions already referred to. Apparently in the formula giving the radius of each of two equal spheres the mutual radiation-repulsion of which balances their gravitative attraction, a square root of 10 was omitted, and the value of that radius should be a=0.6902/101p. A wrong value was also assigned to the density of the sun. Mr. Whitmell has very kindly re-calculated the results depending on this formula, and I have worked them out independently. We now find that two equal spheres will have equal radiationrepulsion, and gravitative attraction with radii as given below:

The last was given previously as 3-4 cm.

Radius in centimetres

1930

6'1 0'5645 113

The effect of radiation pressure on terrestrial dust is worthy of consideration, for it may be quite appreciable when the particles are small and are among surroundings at different temperatures. For simplicity of calculation, let us suppose a very small dust particle, of density p, to be cylindrical with radius a and length a, and let its flat ends be black and let its curved surface be perfectly reflecting. Let it be situated between two indefinitely extended parallel vertical walls, one at a temperature 0,° A., the other at a lower temperature 0,° A., and let its ends be parallel to the walls. The two faces of the dust particle will, if it is small enough, be at very nearly the same temperature, so that we may leave out of account the pressures due to the emitted radiation and consider only those due to that received from the walls. If is the radiation constant 5.32 X 10-5, and if U is the velocity of light, the difference of pressure on the two sides will be 20(0,4-0,4)/3U, and the acceleration due to this on area ra2 and mass pra3 is 20(0,*-0,4)/3 Upa. When p=1, a= = 10-3, 0=400° A., 2=300° A., this acceleration is 0.02 cm./sec.2.

If the law of radiation pressure can be taken as still holding when the radius is reduced to a = 10-3, the acceleration is 2 cm./sec.2. This implies that such a particle of dust, in a vacuum, and between vertical walls respectively at 27° C. and 127° C. would not fall vertically, but would deviate about 2 mm. per metre towards the colder wall.

The effect found by Prof. Osborne Reynolds (Phil. Trans., ii., 1879, p. 770) on a silk fibre exposed to radiation from a hot body, and assigned by him to "radiometer" action, is far larger than this. The radius of the fibre was 0.000625 cm., and its length was probably about 15 cm. When it was hung up in a test tube containing hydrogen at atmospheric pressure, and was exposed to radiation from a neighbouring jar filled with boiling water, the lower end of the fibre moved through 0.01 cm. This would imply an acceleration of about 0.7 cm./sec.2, about sixty times the acceleration on a dust particle of the same radius under the conditions assumed above. The action detected by Reynolds increased, too, very rapidly as the pressure fell, being ten times as great when the pressure was reduced to 1 inch of J. H. POYNTING.

mercury.

The University, Birmingham, December 15.

As regards the Gymnosperms, evidence has been accumulating for some time past indicating their connection with the fern-phylum rather than with the Lycopods. Some account of this evidence will be found in my discourse at the Royal Institution on the origin of seed-bearing plants (1903), while a more recent summary is given in Mr. Arber's article on Palæozoic seed-plants in NATURE for November 17, p. 68.

The seed-like organs of some Palæozoic Lycopods, such as Lepidocarpon and Miadesmia, seem to be cases of homoplastic modification, and not to be indicative of any affinity with those groups of seed-plants which have come down to our own day. D. H. SCOTT.

Jodrell Laboratory, Kew.

The Date of Easter in 1905.

ALREADY queries have been addressed to me on the subject of the date of Easter in 1905, owing to the fact that, according to the almanacs, the moon is full at 4h. 56m. Greenwich mean time on the morning of March 21 next, and that therefore, according to the Prayer Book rule, it would appear that Easter Day should be the Sunday following March 21, viz. March 26. As the misunderstanding on the subject seems widely spread, perhaps you will allow me to explain that the moon referred to in the ecclesiastical calendar is not the actual moon in the sky, which is full at a definite instant of time, but a fictitious moon, the times of the phases of which are so arranged as not to differ much from those of the actual moon. These phases are held to occur, vaguely, on certain days, and therefore hold good for all longitudes, and so avoid a practical inconvenience that would arise from the use of the actual moon. Thus, in the instance before us, in which the actual moon is full at 4h. 56m. a.m. Greenwich mean time, the same moon is full at 11h. 48m. p.m. (on the preceding day) Washington mean time. The people adopting Greenwich time would, therefore, in the supposed circumstances, keep Easter Day on March 26, whilst those adopting Washington time would keep it on April 23.

Perhaps the simplest expression for the date of the Paschal full moon is March (44-epact), which gives the date directly when the epact is less than 24. When the epact is equal to or greater than 24, this expression gives the date of the preceding full moon, and the Paschal full moon is found by adding 29 to this date.

Thus in 1905 the epact is 24, therefore the calendar moon is full on March 20, and again on April 18. The latter is, by the rule, the Paschal full moon, and Easter Day is the following Sunday, viz. April 23.

H.M. Nautical Almanac Office.

A. M. W. DOWNING.

Fishing at Night.

THE notice in your Journal of the "Sea Fishing Industry," written by Mr. Aflalo, suggests to me that he or some other of your readers may inform me why sea fishing takes place for the most part at night. I have heard the subject discussed all my life, and the answers have been of the most opposite and unsatisfactory character, such as to obtain a supply of fish for the morning markets, and because fish come nearer to the surface in the dark. Everyone must be familiar with the sight of our fishing boats preparing to take their departure as the evening approaches in the different harbours on our coasts. Some of the masters, unfortunately, like the Apostle Peter, have toiled all night and caught nothing. S. W. December 20.

A New British Bird!

A FINE example, a male, of the Pacific eider-duck, Somateria v-nigrum, was killed at Scarborough on December 16. This is the first recorded instance of the occurrence of this bird on our shores. Closely resembling the common eider, Somateria molissima, it may yet be readily distinguished therefrom by the bright orange colour of the bill, and the sharply defined, black V-shaped mark on the throat-hence the specific name v-nigrum.

The Pacific eider occurs in abundance along the coasts of north-western America and north-eastern Asia. W. P. PYCRAFT.

Natural History Museum, South Kensington.

Lepidocarpon and the Gymnosperms.

of

THE Concluding sentence in your note on Mr. H. E. H. Smedley's admirable models of the fructifications Paleozoic plants (NATURE, December 22, p. 183) may possibly be misleading to some of your readers. As the models of Lepidocarpon shown in your figure were prepared from my instructions, I may be supposed to share the responsibility for the hypothesis of an affinity between the lycopodiaceous cones and the Gymnosperms, stated to have been urged by "the author," especially as the points of agreement mentioned are quoted, with some slight abridgment, from my paper on the seed-like fructification of Lepidocarpon in the Philosophical Transactions.' Such 1 Phil. Trans. R.S., Series B, vol. cxciv., 1901, p. 320. See also NATURE, vol. lxiii., 1900-1901, pp. 122 and 506.

Intelligence of Animals.

IN reference to the question of intelligence in animals, it may be of interest to mention a case of distinct reasoning power in a cat which for nine or ten years associated himself with our family; he would have scorned the suggestion that he belonged to it. When he found himself on the wrong side of a closed door-a very constant occurrence-he stood up and, catching the handle in his fore paws, rattled it. I do not think he tried to turn the handle, but he certainly knew that it played an essential part in the opening of the door. He is now no more, and de mortuis nil nisi bonum bars any further reference to his career, for he was a dissipated old scoundrel; but it is a pleasure to me to pay, with your permission, the above little tribute to his memory. Greenock, December 17. T. S. PATTERSON.