he was very eager to get the meat out of it, and that when later in the day he succeeded, he showed no manner of misgiving as to his legal right to its possession.

Other of my correspondents misunderstand the purpose of the experiment. They see in it a desire to belittle their canine pets. This was very far from my thoughts. We have innumerable anecdotes telling us what dogs can do. I wish, partly I admit with a view to enabling us to sort these stories, to obtain, as data, definite observations showing what dogs will not do. Into most dog stories there creeps the little touch of human nature which makes them and ourselves akin.

Mine is the point of view of an anatomist. A dog has a brain very different from that of man. Brain and mind are the two sides of the same coin; or rather, brain is the coin, mind its value. The dog's brain cannot make a man's thoughts. How near can we come to picturing to ourselves the nature of a dog's thoughts? Without committing ourselves to Flechsig's theory of the division of the cortex of the brain into projection areas " and "association areas," we may on anatomical grounds assert that the cortex of a dog's brain contains fewer association elements than does that of a man. It is an apparatus for transforming sensory impressions into actions, in a more limited and exclusive degree. Probably we can best picture to curselves the work that it does by supposing that the wordless thoughts of animals are direct combinations of sensory impressions; whereas man has invented symbols for his sensory impressions. He works the symbols into thought. Nor do his symbols stand for material objects alone. They also stand for inferences from observations. But this is a subject which perhaps I ought not to touch without having at my disposal more space than I can ask you to give me in your Journal.

We must admit with Sir William Ramsay that dogs make use, in their mental operations, of sensory impressions and not of inferences, although I dissent from his qualification of their impressions of smell as "vague. It is my object to ascertain, by means, if possible, of observations which can be made under properly controlled conditions upon numerous dogs of various breeds, the limits of their power of substituting inferences for sensory impressions materials of thought.

a

as

THE phenomenon mentioned by W. L. must have frequently been noticed; while resembling that described by me as a proof of the spherical aberration of the eye, it is yet due to an essentially different cause. The black line, when placed at a distance of five or six inches from the eye, is within the shortest distance of distinct vision from the latter. A point source of light, situated on the axis of the eye, at a position closer to the eye than the" near point," produces a relatively large spot of light on the retina. If the pupil be now progressively covered froni above, the rays passing through the middle and upper part of the pupil will be cut off, so that those passing through the lower part of the pupil alone remain; these cut the retina in a comparatively restricted area below the point of intersection by the axis of the eye, so that the image apparently rises, at the same time becoming more sharply defined. Under the conditions mentioned, the same phenomenon would be observed if the eye were entirely free from spherical aberration. For this reason I stated that the black band should be placed just beyond the shortest distance of distinct vision from the eye; care must be taken to keep the eye carefully focused on the edge of the black band, er an exaggerated displacement, due to relaxation of the асtотmodation of the eye, may result." It was merely as a proof of the spherical aberration of the eye that I described this experiment as having apparently escaped observation. April 12. EDWIN EDSER.

Is connection with the experiment on the spherical aberration of the eye, described in your issue of April 16, I may relate a striking observation I made some years ago, Regard with one eye any light or bright object on the wall, turn the head away until the object is just covered by the line of the nose; then move the eve to its natural position, and the object will reappear, supposing the nose is not too prominent. Moving the eye several times to and fro, the phenomenon will be easily observed. Leipzig, April 29.

W. BLIZ.

THE SOLAR AND METEOROLOGICAL CYCLE OF THIRTY-FIVE YEARS,

T

ference. We may accept it as an axiom that an animal can draw an inference of this kind. It is not yet established, by experimental methods, that an animal can combine two inferences, or, as I venture to term it, "reason in the second degree." My box-experiment was intended to throw light upon this question. I shall be very grateful for any further suggestions of possible experiments of the same kind. ALEX. HILL.

Downing Lodge, May 2.

Spherical Aberration of the Eye.

WITH reference to the experiment described by Mr. E. Edser (p. 559) as appearing to have escaped observation," perhaps I may be allowed to state that this phenomenon was (to the best of my recollection) described by me before the School Natural History Society when I was a boy at Rugby, about 1873-1874. I could not explain it, and no one at the meeting had any suggestion to make.

I think I connected it in my mind with irradiation phenomena, though I was baffled by the fact that the whole line is bent.

If the black horizontal lines drawn between different advertisements on the outside of NATURE be held five ori six inches from the eye, and the rounded end of a pen be brought down close to the eye, the whole line will be seen to curve upward to meet the pen, becoming also blacker and more distinct. W. L.

HE fact that the rainfall of many regions of the earth's surface has, for the last decade or more, been gradually diminishing has led many inquiries to be made concerning the possible periodicity of this meteorological element, and during the last few months more general attention has been drawn to this interest

not only to agriculturists but to others, renders it desirable that all facts which may tend to elucidate the subject should be thoroughly discussed.

The object of the present article is to bring together, without entering into too great detail, a few statistics relating to the rainfall of different stations in various parts of the earth to see whether there be grounds for assuming a continuation of the present small supply, or whether a greater abundance may be looked for with special reference to the condition of the British Isles.

A few introductory remarks may here not be out of place. Eduard Brückner first discovered that wet periods, great droughts, &c., occurred at intervals of about thirty-five years, and he published his important conclusions in a volume which was, and still is, a valuable contribution to meteorological science. take one element only, namely, rainfall, Brückner showed that during the last century the mean epochs of the wet years were 1815, 1846-50, and 1876-80, while those for the dry years were 1831-35 and 1861-65.

To

Since the publication of this volume, many workers have studied rainfall and other records extending over long periods of time. Thus, to take one instance among many that might be cited, Herr Hofrath Julius Hann, the distinguished late director of the Vienna Meteorological Institute, made a minute investigation of the

past, or on the point of coming to a conclusion, and in all cases the general tendency of the long period curve is now to rise again. This indication of the increase of the rainfall is represented in the figure by the dotted continuation of the secular variation curves for each station, and should the apparent law hold good, there seems sufficient evidence to mark that this rise will continue to take place until about the year 1913, which year will suggest the middle of the next wet epoch.

It may be mentioned, however, that owing to the great oscillatory nature of the rainfall from year to year, this rise only represents the mean rise when several

In conclusion, attention may be drawn to the fact that during the last few years a far more close connection between solar and meteorological phenomena has been made out than was the case some years ago, and since this long period rainfall cycle synchronises so well with the solar changes, the latter may render valuable assistance in determining the epochs of these dry and wet cycles. WILLIAM J. S. LOCKYER.

ETIOLATION.

dry years even when the secular variation curve is at a maximum, but on the average they will probably

be wet.

What causes this long period of weather variation is not yet definitely known, but it is of the highest importance to meteorological science that the matter should be cleared up as soon as possible, for not only is our rainfall involved, but all other meteorological m elements show similar fluctuations.

Brückner attempted to account for this long period weather cycle by attributing its origin to a change in the activity of the sun, and he investigated the sunspot data then available for evidence of a periodicity of about thirty-five years. He was not, however, successful in his research, but he concluded that, although this variation must really exist in the sun, yet it might not necessarily be indicated by sunspots. More recently a minute examination of the sunspot observations made since the year 1832, when a systematic method of observation had been initiated, has led to the discovery of such a period, a detailed account of which appeared in a previous number of this Journal (NATURE, vol. Ixiv. p. 196). It was there shown that each sunspot period (reckoning from minimum to minimum) differed in many respects from the one immediately preceding or following it. Some periods, for instance, were not only more "spotted " than others, that is, the summation of the whole spotted area from one minimum to the next varied regularly, but these particular periods were closely associated with comparatively rapid rises from minimum to maximum in those periods. These changes further seemed to be undergoing a regular variation, the cycle of which was determined to be about thirtyfive years.

The connection between Brückner's cycle and this long period solar change of thirty-five years was there briefly stated, and it was shown that at those two epochs of sunspot minima, namely, 1843 and 1878, which follow the cycles of greatest spotted area, the Brückner rainfall cycle was at a maximum.

The close correspondence of the epochs of these two cycles suggested at once a probable cause and effect, a cause which Brückner himself had suggested and looked for, but unfortunately did not find.

In the accompanying figure the uppermost curve represents the sunspot curve from the year 1832, and the minima just referred to are indicated by the vertical dotted lines, which are continued through all the curves. The periods of greatest spotted area just precede these epochs, and the times of maxima are shown by the vertical continuous lines drawn in a similar manner. To show the probable times of the recurrence of these epochs during a portion of the next great period of thirty-five years two vertical lines have been inserted at the years 1905, which is the probable epoch of the next great maximum, and 1913, the following minimum, so that their relation to the probable variation of rainfall, as indicated by the dotted portions of the curves, can be seen at a glance.

Daly Lydig fund

bequeathed by Charles P. Daly, and embodies the results of the author's investigations extending from 1895 to 1902, and one of the first questions it arouses is, to what extent is this sustained experimental work stimulated by the certainty o adequate publication owing to the generosity of patriotic endowment, and to what extent does such work react on the pockets of friendly millionaires and induce the endowments for further work? In any case, Americans are fortunate in their circumstances in these respects.

The book, which comprises more than 309 pages of text and 176 figures, all admirably done, is divided into three principal sections. There is, first, a summary of the history of the subject, beginning with Ray (1686) and Hales (1727), and occupying 34 pages of more or less critical notes. It is, of course, impossible for us to verify the enormous number of the references to this part of the subject, but if the author has made many such blunders as those on pp. 27 and 29, where on two separate occasions he cites volumes and pages as from Proc. Roy. Soc. when he should have written Philosophical Transactions, the value of his bibliography must suffer. If a leading American plant physiologist does not know the difference between the two publications referred to, it is time he did; if he does, the inference that he has not consulted the original memoirs is as inevitable as it is dispiriting.

The second chief division of the work occupies the bulk of the book, pp. 35-200, and reflects credit on the author and his pupils for their industry and clearness of description, as well as for the interesting choice of plants selected for experiment. These include not only ordinary flowering plants, but also more out of the way forms of monocotyledons and dicotyledons, as well as ferns, Equisetum, &c. The one note of disappointment in this portion of the book will be struck by the want of plan. Numbers of most interesting observations on the behaviour of particular species in the dark, and illustrations of their facies, their anatomy compared with that of normal plants, their curves of growth and so forth will make the book useful to all investigators; but the plants are arranged in alphabetical order, and when the reader turns to a particular species he has no guide as to how it will be treated. Thus, taking at random Salvia, Sansevieria, Sarracenia, Saururus, and Sparaxis, which follow in the order given on pp. 171-180. The first merely heads a small paragraph stating that the corolla is atrophied in darkness. Under Sansevieria the etiolation of the shoot is described only in so far as external changes are concerned. In Sarracenia the effects of etiolation on the histology of the epidermis lining the pitchers " are well illustrated. Saururus figures of the anatomy of etiolated and normal stems, and measurements of height and thick

In

1 "The Influence of Light and Darkness upon Growth and Development." By D T. Macdougal, Ph.D., Mem. New York Bot, Garden. Vol. ii. Pp. xiii + 319. (1903.)

ness form the theme; while Sparaxis heads a short paragraph recording failure of growth.

All this suggests a heterogeneous collection of student's notes as the groundwork of the memoir, and interesting and useful as many of these are, they might have been rendered more valuable by classification and efficient editing.

The third portion of the book is occupied with general considerations, and embraces summaries of the foregoing, theories as to the nature of etiolation, and so

forth.

Here, of course, we look for the author's own views, but with the exception of vague statements here and there, the concluding portions of the book force us reluctantly to decide that, important and interesting as the memoir is, it is so not so much as a work of original thought and suggestion, but as an extensive and more or less critical survey of what others have done. In this category it stands well, and may be recommended, but we do not like such sentences as the following exercise for the grammarian and the physicist :

It is, of course, entirely probable that the action of light may set up chemical processes in the plant is in a manner entirely stimulative, and independent of any communication or transformation of energy (p. 201).

PROF. J. WILLARD GIBBS.

THE announcement of the death of Prof. J. Willard Gibbs, of Yale University, will be received with the deepest regret by the whole of the scientific world. There are few workers who have done so much as Prof. Willard Gibbs to teach the lesson that it is to the mathematician that the experimentalist must look for new ideas. The papers which have made his name famous date from 1873, when he published in the Transactions of the Connecticut Academy Academy his on the geometrical representation of the thermodynamical properties of bodies. Gibbs first discussed the advantages of using different thermodynamical variables for graphic representation, and then discussed the surface formed by taking as coordinates the volume, entropy and energy of a body. "Gibbs's thermodynamical model," or "thermodynamic sur

paper

face" as it is now called, has become best known to English readers through the account given in Maxwell's "Theory of Heat." The study of the properties of thermodynamical surfaces has afforded a wide field of research, which is still continuing to yield new results in the hands of the Dutch school of physicochemists. A remarkable feature of the investigation is the geometric representation of the conditions of thermodynamic stability, which does much to remove the difficulties attaching to any algebraic form of enunciation. A further paper, entitled Graphic Methods in the Thermodynamics of Fluids," was published in 1878.

Gibbs's epoch-making papers par excellence are, however, those dealing with the equilibrium of heterogeneous systems, the first of which, dealing with chemical phenomena, was published in June, 1876, while the second, dealing with capillarity and electricity, appeared in July, 1878. The most essential feature of Gibbs's discoveries consists in the extension of the notion of the thermodynamical potential to mixtures consisting of a number of different components, and the establishment of the properties that this potential is a linear function of certain quantities which Gibbs has called the potentials of the com

ponents, and that where the same component is present in different phases which remain in equilibrium with each other, its potential is the same in all the phases, besides which the pressures and temperatures of the phases are equal.

The importance of these results was not realised for a considerable time. It was difficult for the experimentalist to appreciate a memoir in which the treatment is highly mathematical and theoretical, and in which but little attempt is made to reduce conclusions

to

It

the language of the chemist; moreover, it is not unnatural to find the pioneer dwelling at considerable length on comparatively infertile regions of the newly-explored territory, while points of vantage which have subsequently proved to be the most productive fields of stud study were dismissed very briefly. was largely due to Prof. van der Waals that two new and important fundamental laws were discovered in the paper, namely, the phase rule and the law of critical states, and the consequences of the first of these laws were the subject of remarkable developments in the hands of Bakhuis Roozboom, Schreinmakers, Storten-. beker and Wilder Baneroft. The well-cultivated tracts of knowledge which represent a most important branch of modern physical chemistry bear but little resemblance to the crude, often circuitous path, full of stumbling blocks and difficult obstacles by which Gibbs first opened up this region. The study of dissociation phenomena has afforded some of the most beautiful experimental verifications of Gibbs's theories, which have done much to convert theoretical chemistry into a branch of applied mathematics.

It is not the physicist and chemist alone who are indebted to Prof. Gibbs; he has also made his mark among mathematicians in connection with the study of quaternions and vector algebra. Physicists claim that in the Hamiltonian system of quaternions there is a loss of naturalness from the fact that the square of a vector becomes negative. Gibbs met the objection by suggesting an algebra of vectors with a new notation, the expression for the product of two vectors being formed in such a way as to give a positive value for the square of a vector. His paper on "Multiple Algebra " was published in the Proceedings of the American Association for 1886.

of

Gibbs's attention has recently been turned to remodelling the mathematical theories underlying the kinetic theory of gases, and the law of pa partition energy. His work on statistical mechanics has been before us for about a year, but so difficult is the subject that a considerable further time must elapse before it can be widely understood and appreciated. His interpretation of the determinantal equation as the principle of conservation of extension in phase, his methods of dealing with ensembles of systems, and his establishment of the existence of irreversible phenomena in connection with such ensembles are all distinct advances, but in connection with the lastnamed properties an idea necessarily forces itself on one that there must be some assumption underlying the proof which might with advantage be discussed more explicitly than was done in the treatise in question, and his loss at the present time deprives us of the prospect of further enlightenment on difficulties which no amount of mere mathematical formulæ will clear up.

As mentioned last week, he was elected Foreign Member of the Royal Society in 1897, and received the Copley medal in 1901. He was also an honorary or corresponding member of the British Association, the Cambridge Philosophical Society, and many other learned societies both in this country and abroad.

G. H. B.

NOTES.

THE annual conversazione of the Royal Society will be held on Friday, May 15.

THE following fifteen candidates have been selected by the council of the Royal Society to be recommended for election into the Society: Dr. W. M. Bayliss, Prof. T. W. Bridge, Dr. S. Monckton Copeman, Mr. Horace Darwin, Mr. W. P. Hiern, Mr. H. R. A. Mallock, Prof. D. Orme Masson, Mr. Arthur G. Perkin, Prof. E. Rutherford, Prof. R. A. Sampson, Mr. J. E. Stead, Mr. A. Strahan, Prof. J. Symington, Prof. J. S. Townsend, and Mr. A. N. Whitehead.

Ar the annual general meeting of the Institution of Civil Engineers, held on April 29, Sir William H. White, К.С.В., F.R.S., was elected president for the sessional year 19031904.

DR. P. CHALMERS MITCHELL has been elected secretary of the Zoological Society in the place of Mr. W. L. Sclater, who held the office as acting secretary since the retirement of his father, Dr. P. L. Sclater, F.R.S., last year.

FURTHER particulars of the work and position of the National Antarctic Expedition have been brought by the New Zealand mail, and are published in Wednesday's Times. The chief scientific work accomplished by the expedition is summarised as follows:-(1) The discovery of extensive land at the east extremity of the great ice barrier. (2) The discovery that MacMurdo Bay is not a "bay," but a strait, and that Mounts Erebus and Terror form part of a comparatively small island. (3) The discovery of good winter quarters in a high latitude-viz. 77° 50′ S., 166° 42′ E.-with land close by suitable for the erection of the magnetic observatories, &c. The lowest temperature experienced was 92° of frost Fahrenheit. (4) An immense amount of scientific work over twelve months in winter quarters, principally physical and biological. (5) Numerous and extensive sledge journeys in the spring and summer, covering a good many thousand miles, of which the principal is Captain Scott's journey, upon which a latitude of 82° 17′ south was attained, and an immense tract of new land discovered and charted as far as 83° 30' south, with peaks and ranges of mountains as high as 14,000 feet. (6) The great continental inland ice reached westwards at a considerable distance from the coast and at an altitude of 9000 feet. (7) A considerable amount of magnetic work at sea, also soundings, deep-sea dredging, &c. Commander Scott's narrative of the expedition and statement of scientific observations, telegraphed from Lyttelton, and given in our issue of April 2 (p. 516), is thus confirmed. It was not clear at the time of the cable message why the Discovery could not get out of the ice, though the relief vessel, the Morning, had done so and returned to New Zealand. It is now known, however, that the Morning only got within about eight miles of the Discovery, and the stores had to be transferred by means of sledges. As the Discovery has not returned to Lyttelton, there is little doubt that the expedition has been forced to spend a third winter in the Antarctic. additional expense will thus be incurred, and it is estimated that from 12,000l. to 20,0ool. more will be needed to meet it.

Much

THE death is announced of Mr. C. Bartlett, late superintendent of the Zoological Society.

A UNIVERSAL Exposition of Sciences, Arts, and Industries is to be held at Liége in the year 1905.

THE death is announced of M. de Bussy, member of the Institute of France, and well known as a naval engineer.

An earthquake shock, lasting five seconds, was felt in villages between Worksworth and Derby on Sunday, May 3, at 9.20 p.m.

ACCORDING to a Central News message from San Francisco, dated May 1, a report from San Juan states that the Santa Maria volcano in Guatemala is in a state of active eruption.

THE Louis Pillet prize of the Chemical Society of Paris has been awarded to M. E. Theulier, director of the technical staff and head of the research laboratory of Messrs. Lautier fils, of Grasse.

An international exhibition of agriculture and horticulture, which the Cercle grand-ducal d'Agriculture et d'Horticulture du Grand-Duché de Luxemburg is organising at Luxemburg on the occasion of the fiftieth anniversary of its foundation, will be held from August 29 to September 7.

It is announced in Science that the Donohoe comet-medals of the Astronomical Society of the Pacific have been awarded to M. Michel Giacobini, of Nice, for his discoveries of unexpected comets on December 2, 1902, and January 15,

1903.

THE proposed electric railway to the summit of Mont Blanc is to be commenced shortly. The municipal authorities of Saint Gervais-les-Bains have accepted the scheme, and have accorded the concession to the French engineers, MM. Deruad and Duportal.

A NOTEWORTHY point in connection with the illuminations of Paris, organised by the reception committee in honour of the King's visit, was the electric incandescent lamps of different colours in the chief streets and avenues and on many large buildings. The effect was very brilliant, and the large crowd of sightseers admired it exceedingly.

THE council of the Society of Arts is prepared to award, under the terms of the Benjamin Shaw Trust, a prize of a gold medal, or twenty pounds, for the best dust-arresting respirator for use in dusty processes and in dangerous trades. Inventors intending to compete should send in specimens of their inventions not later than December 31 to the secretary of the Society of Arts, John Street, Adelphi, London, W.C.

INVITATION cards in the name of the president of the Institution of Electrical Engineers are being issued to members of the Institution for a concert to be given at the Royal Albert Hall on the evening of Thursday, June 11, on the occasion of the International Telegraph Conference.

The annual conversazione of the Institution will be held at the Natural History Museum on the evening of Tuesday, June 23. This date has been selected as one on which it will be possible for the members of the International Telegraph Conference to be present.

On Tuesday next, May 12, Prof. G. H. Darwin delivers the first of two lectures at the Royal Institution on "The Astronomical Influence of the Tides," and on Thursday, May 14, Prof. S. H. Vines begins a course of two lectures Proteid-Digestion in Plants." The Friday evening discourse on May 15 will be delivered by Dr. D. H. Scott on the Origin of Seed Bearing Plants."

on

THE new Johnston Laboratory at University College, Liverpool, is to be opened by Mr. Walter Long, M.P., President of the Local Government Board, on Saturday, May 9. Many distinguished men of science have expressed their intention to be present at the ceremony. On Monday, May 11, a conference on tropical sanitation will be held in the college.