of this change seems to be that the temple service had become more complicated, and more time was required by the priests for their preparations. Every additional degree of sun depression would add about five minutes for that purpose. The maximum extra allowance in this group of temples is thirty-five minutes. F. C. PENROSE.

NATURE AND A CAMERA.

THE HE remarkably favourable reception accorded by the public and the press to the earlier effort of the Messrs. Kearton has naturally tempted them to another venture; and the volume before us shows no falling off in the matter of interest and the exquisite execution of the illustrations from its predecessor. Only too frequently authors, having scored one success, are apt to think their hold on the public will permit of a very inferior second effort obtaining the same share of patronage as the first, and any odd scraps of new information they

FIG. 1.-Nightingale on Nest. (From "With Nature and a Camera.") may possess are, with the aid of abundant " padding," worked up to form a volume of the required dimensions. The present work displays in an equally marked degree the freshness and brightness so conspicuous in "British Birds' Nests"; and as covering a wider area is calculated to attract an even larger circle of readers. One of the best tests of a work of this nature is its capability of arousing the interest of young persons, and this, from practical experience, we find to be the case with the volume before us.

Photography in the hands of artists of the capacity and perseverance of Mr. Cherry Kearton is undoubtedly the only real method of portraying animals in their

"With Nature and a Camera, being the Adventures and Observations of a Field-Naturalist and an Animal Photographer." By R. Kearton, with Photographs by C. Kearton. 8vo. Pp. xvi +368, illustrated. (London: Cassell and Co., Ltd., 1897.)

native haunts, and more especially birds on their nests; and in the truthful representations of objects of the latter class the present volume can fear few rivals. Nothing can be more exquisite than the illustration of a nightingale on her nest, which the publishers have permitted us to reproduce (Fig. 1); but this is only one among many of the same excellence and interest, those of the whitethroat and the chiffchaff being, if possible, even more beautiful. The only thing we miss in illustrations of this nature is colour, which would be of especial value in photographs, like the upper one on page 253, dealing with the protective resemblances of animals to their surroundings. Possibly even this want may be supplied in the near future.

alone that calls for commendation in the work; many of But it is by no means the beauty of the illustrations the observations in the text claim recognition from all interested in the habits of British animals, while some have a bearing on considerations of a higher nature. For instance, in regard to protective resemblance, Mr. Kearton says he is puzzled by the circumstance that while young terns instinctively recognise its value, some of their parents apparently do not and others do. This is exemplified as follows: "As a rule, Sandwich terns eggs harmonise closely with their surroundings, and even the experienced field naturalist has to exercise a great deal of care to avoid treading upon a clutch when visiting a breeding station. A friend of mine told me a few years back that he had once visited a colony of these birds on an island where the natural breeding accommodation was so limited that many of them had conveyed patches of pebbles on to the grass, and laid their eggs thereon. We both recognised this as a wonderful instance of the knowledge of the value of protective coloration; but I must confess that last summer at the Farne Islands my faith in the wisdom of these birds received a rude shock when I met with five or six clutches of eggs lying most conspicuously on small circular patches of broken mussel-shells, the dark blue of which contrasted violently with the golden grey of the sand." From this it would almost seem that the birds are unable to distinguish between a mussel- shell and a pebble, and that any cluster of small smooth objects looks to them equally suitable as a nesting site.

Although the greater portion of the work is devoted to birds in their haunts, the subjects treated of are diverse. To the general reader and tourist the chapters on the people and birds of St. Kilda will, perhaps, be the most interesting; while the sportsman will find much to attract him in those on gamekeepers and duckdecoying. To the amateur photographer the volume will appeal not only as a standard of excellence at which to aim as regards his own efforts, but more especially from the account given in the final chapter of Mr. Kearton's method of photographing. From this latter it will be apparent that the task of portraying many kinds of birds especially when they inhabit lakes or beetling sea-cliffs in their native haunts, is no easy one, but rather one beset with numerous dangers to life and limb. In the preface the author deprecates the charge of foolhardiness, and the results obtained go far to justify the risks necessarily incurred.

In the chapter on sea-birds and their haunts will be found some of the matter most interesting to the ornithologist, and it is here that some of the most successful of the photographs occur. As an example, we select, partly on account of its small size, the figure of a solitary razorbill mounting guard over its egg reposing lower down on the side of a pinnacle of rock (Fig. 2). But for beauty of detail and execution we may refer to the gull's nest with egg and young, and the group of puffins on p. 269, and also to the nest of the black-headed gull on the following page. To obtain the photograph of gannets nesting on the Bass Rock, Mr. Cherry Kearton ran risks

which evoked the fear of even the adventurous natives of the district. When once their haunts are gained, gannets with young are however, according to our author, very easy birds to photograph, as they will permit the observer to walk among them with no more protest than an occasional peck at his legs. Much has of late years been written on the destruction by human agency of our sea-birds; and it is, therefore, of interest to note that other causes likewise aid to no inconsiderable extent in the diminution of their numbers. "The mortality among sea-birds of all kinds," writes our author, "reckoning the loss of eggs and young ones, from purely natural causes alone, must be very great in the course of a season. We saw a great number of young terns lying dead everywhere upon these islands, and Watcher Darling told us that two years ago very few Arctic or common terns got away. He picked up several dead

FIG. 2.-Razorbill and Egg. (From "With Nature and a Camera.") ones with sand-eels in their bills, and concluded that there was no small fry for them, and that the eels, although the natural diet of Sandwich terns, were too large for the young of the smaller species to swallow."

Most of us suppose that the eider is pre-eminent for the quantity of down she employs for lining her nest; but in this, according to our author, she is beaten by the common wild duck. Did space allow, many other observations of equal interest might be quoted, but for these we must refer the reader to the work itself, which will form a welcome Christmas gift to all, whether young or old, interested in wild nature. R. L.

DR. FRIEDRICH A. T. WINNECKE. T is always a painful duty to review the life work of those who have recently passed away, to estimate the position their names will occupy in the history of a science, and to survey the grounds on which their reputation will finally rest. But in the case of Dr. Winnecke, whose death was recorded last week, the task becomes both painful and difficult. Thirty years ago he occupied a prominent position among continental astronomers, and

was intimately connected with the onward growth and development of the science in many important directions. His enterprise and ability were everywhere acknowledged, and a long career of work and usefulness seemed before him. But while he was still a comparatively young man, the state of his health prevented him from adding to the reputation he had established, and to-day his name is perhaps little more than a memory to many, who, interested in newer problems and more sensational inquiries, may possibly undervalue the work of an older school, which occupied itself mainly in the astronomy of position. But wherever a just and comprehensive view of astronomy as a whole is taken, Winnecke's work will be remembered with gratitude and admiration.

Dr. Winnecke enjoyed the advantage of admirable mathematical training under competent teachers. The school of Bessel was then in the ascendant, and the reputations of Encke and of Argelander were at their zenith; while in the district of Hanover, where Winnecke passed his early years, the memory of Herschel was still treasured, and helped to give direction to his astronomical tastes. He received his training in practical astronomy mainly at Bonn, under Argelander, where he became a proficient in the use of the heliometer, and with this instrument effected a complete triangulation of the stars in the Præsepe cluster, together with a thorough examination of the necessary constants of reduction. This latter part of the work he prepared himself for publication, but never printed, and it forms a painful commentary on his enfeebled energies to remember that this work never saw the light till many years after, when Dr. Schur proved himself an able and sympathetic coadjutor, and arranged the numerical portion of the research for general In 1858, Winnecke left Bonn for Pulkova, where he still interested himself in extra-meridional work. The fine series of observations of the great comet of 1861, which he followed until May 1862, long after it had ceased to be observed in other telescopes, and on which the final orbit rests, is a proof of both his energy and his observational skill. Cometary astronomy always had for him great attractions, and besides the periodic comet which bears his name, he found several others, receiving the prize of the Vienna Academy of Sciences for his cometary discoveries. At Pulkova, too, he took some part in the geodetic work arranged between Dr. Otto Struve, Argelander, and the late Astronomer Royal, for determining the differences of longitude between places on the great European arc of parallel, and, in conjunction with Colonel Forsch and Captain Zylinski, carried through that portion of the scheme which connects Haverford West with Nieuport and Bonn.

use.

Winnecke also bestowed some attention on the problem of the sun's distance, which forty years ago was a burning question. Hansen and Le Verrier were contending for the rejection of Encke's value of the parallax as the outcome of mathematical investigations based on the lunar and planetary theories, and were supported by the result of Foucault's mechanical operations arranged to determine the velocity of light. Winnecke was among the first to perceive the importance of obtaining evidence from independent sources, and fully appreciated the value of utilising the observations of Mars as a new element in the discussion. The result of his investigation of the observations made at the 1862 opposition was to assign to the Solar Parallax a value of 8" 964, confirmed by Stone's result of 8" 932.

After leaving Pulkova, Winnecke settled for some years in Karlsruhe, where he was an industrious observer of comets and variable stars. On the conclusion of the Franco-German war, he was invited to take charge of the new observatory at Strassburg. The equipment of this observatory and the details of its arrangement are due to his superintendence, and it certainly ranks among.

agreed that the report should be referred back to the Committee for final consideration, and that as soon as complete it should be issued to the Societies. The Hon. Secretary reported that a National Photographic Record Association had been formed under the presidency of Sir J. Benjamin Stone, M.P., who had been at the head of the original Warwickshire Survey. He was directed to communicate to the Association that "The Congress hears with great satisfaction of the formation of a National Photographic Record Society, and expresses its desire to assist the work in any way it can."

MR. W. A. KNIGHT, writing from Bruton, Somerset, informs us that on November 30, at 10.20 p.m., he was fortunate enough to observe there a splendid lunar rainbow. The moon was sufficiently near the horizon to give a large arc, and although it was scarcely quarter-full, the black clouds looming in the north-east made the bow appear quite bright. There appears to be no doubt that what Mr. Knight saw was a lunar rainbow and not a halo, for it was opposite the moon.

PROF. A. RIGGENBACH has sent us the results of seven years' rainfall observations at Basle, deduced from a selfrecording gauge. Of course the period is very short, and in dealing with monthly and annual means the author combines the values with those of an ordinary gauge, giving altogether a series of thirty-three years. But the principal object of the paper is to bring out some interesting details, which cannot well be obtained from an ordinary gauge. Among these we may mention the frequency and duration of very heavy showers, the great majority of which last only about twenty minutes. Sixty per cent. of these occur between 1h. and 7h. p.m., and 87 per cent. occur between June and September. In the yearly range the rainfall probability reaches a maximum in the early summer and in the late autumn, while the minima fall in midsummer and in the first months of the year. In the daily range the duration of rainfall reaches a maximum between 6h. and 8h. a.m., and falls to a shallow minimum at 7h. to 8h. p.m., after which it rises uniformly to the maximum again. The various phases are shown both in tabular and graphical form. Dr. Riggenbach is perhaps best known to English meteorologists by the success with which he has prosecuted cloud photography. HERR OTTO BASCHIN contributes to the Verhandlungen der Gesellschaft für Erdkunde zu Berlin an account of the fitting out and departure of Andrée's balloon expedition. The different possibilities as to the fate of the explorers are discussed, and the

conclusion reached that there is as yet no reason to give up hope of their return. Under the most favourable circumstances the balloon might easily deposit its passengers on a part of Northern Siberia, from which it would take months to reach the nearest telegraph station.

THE new number of the Mittheilungen von Forschungsreisenden und Gelehrten aus den deutschen Schutzgebieten con. tains some items of geographical interest. Dr. F. Stuhlmann contributes a paper on the German-Portuguese frontier in East Africa, with a new map of the mouth of the Ravuma. In the same region Lieut. Stadlbaur gives a short account of the Turu district and its people; whilst First Lieutenant Freiherr von Stein describes the Ossa or Lungasi lake, on a tributary of the Savaga in the Kameruns.

are these five contributions to human knowledge: the establishment of the principles of evolution; the establishment of the principle of the conservation of energy; the development of mathematical science and its application to physics, mechanics, electricity and astronomy; the development of spectrum analysis and the consequent discoveries respecting light and electricity; and the discovery of the nature and functions of bacteria, and of their influence, for weal or woe, upon living organisms.

As the result of an investigation of the red spectrum of argon, Dr. J. R. Rydberg comes to the conclusion (Astrophysical Journal, November) that it belongs to one single element. Moreover, there seems to him to be no reason to doubt that the blue spectrum belongs to the same element, but corresponds to a higher temperature. As to the supposed displacement of a great number of the lines of the white spectrum towards the red end of the spectrum, it is remarked, "nothing seems to indicate that we have to do with a continuous displacement, but rather with the appearance of new lines on the red side of those of the other spectra, with which they ought to be closely related. In such a case it seems most probable that the interesting observation of Eder and Valenta depends on a change in the relative intensity of two sets of connected lines." IN the Philosophical Magazine for December, Mr. J. D. Hamilton Dickson examines the relation between the electric resistance of a metallic wire and the temperature. Although it has been demonstrated that platinum is a suitable substance for determining temperatures over a very wide range, not much different probably from 2000° C., nevertheless, seeing that each platinum thermometer needs at least to have its constant specially and carefully determined, not by three, but by a series of observations, it cannot be too strongly urged that this work should in each case accompany the record of results when expressed in platinum temperatures; and no one will deny that to have these results expressed at once in terms of the normal airthermometer will permanently enhance the value of the work in such a manner as to amply recompense the extra labour. With the view of helping towards this desirable end, Mr. Dickson proposes a formula of the form (R+a)2= p(t+b), where a, p, b are constants, and gives reasons for considering it as more representative of the connection between temperature and resistance than any formula hitherto proposed, and just as simple as any.

AN interesting extension to space of n dimensions of Euler's and Meunier's theorems on the curvature of surfaces has been

given by Signor Luigi Berzolari in the Atti dei Lincei, vi. IO. The author proves the following propositions:-Given in S, a form of n- I dimensions, the curvature (of Kronecker) at any point of any hyperplane section is equal to the curvature of the hyperplane section having the same trace on the tangent hyperplane at that point divided by the -2th power of the cosine of the angle between the hyperplanes. The curvature of the normal hyperplane section at O is a maximum when the trace of the cutting hyperplane on the tangent hyperplane at O is one of the principal sections S,, - 2 of the indicatrix, and the sum of the curvatures of any n- I hyperplane normal sections mutually at right angles is constant.

DETERMINATIONS of the thermal conductivity of ice by different observers have hitherto exhibited a remarkable discrepancy of results, the values of this coefficient being, according to F. Neumann, 0.34; De la Rive, o'14; Forbes, 0134 and o 128, according to direction; and, according to Mittchel, 030, the centimetre, gramme, minute and degree Centigrade being taken as units. In the Atti dei Lincei, vi. 9, Signor Paolo Straneo describes a simple method of determining this coefficient.

one kind, 0.312 and 0.313 for the other. A further determination gives 0 304 for the first kind; hence, generally, lies between 030 and 0.31. Noticing that certain kinds of ice are anistropic, the properties being different along the vertical and horizontal directions referred to the position when frozen, Signor Straneo, in a subsequent paper, investigates the question as to whether the thermal conductivity varies with the direction. In homogeneous amorphous ice the values for the vertical and horizontal directions were found to be practically equal (0.312 and o 308), but homogeneous non-amorphous ice gave for the same directions 0.328 and 0.301 respectively in one experiment, and 0.325 and 0 308 in another, showing that only ice which is not perfectly amorphous presents small differences in the coefficient of conductivity in different directions.

THE physical aspect of the reversal of the photographic image is the subject of a suggestive paper by Captain Abney in the Journal of the Camera Club. To investigate the matter, a series of photo-micrographs of sections of films which had been given known exposures was taken. From these sections it is seen that the part of the films in which reversal has taken place are markedly different at the upper and lower surfaces. Near the upper surface the section shows comparatively fine grains of silver, whilst at the bottom surface it shows coarser grains. At the top part of the film, where the light has acted strongly, the reversal has taken place. At the bottom the light has not acted much more than usual, owing to the shielding action of the top part. When given areas of the film are examined, the numbers of separate silver particles are found to be very much the same in both cases, showing that there is a sort of normal number per volume which is subject to reduction, and that the main difference is in the size of the reduced particles. In the course of a discussion upon the subject of the paper, Dr. Armstrong, referring to the sections of the unreversed image, considered that Captain Abney had shown that to be the case which must be the case, and that so long as there was no reversal the particles must be practically as large as the bromide particles, and all of the same dimensions. By showing that the particles in the reversed image were so very much smaller, Captain Abney had contributed in an important degree to the solution of the character of the change that took place; it appeared to him that it had been shown that there was in some way a reconversion of the surface of the particle into soluble matterthat evidence had been adduced to prove that there must be a re-transference of the bromine back into the silver at the surface, leaving untouched the silver lower down in the particle, and consequently that when the fixing solution was applied, the particle became reduced in size.

AN article of perhaps no little interest to many persons in this country, and of some substantial importance to Spanish industries, is the so-called gut from silkworms. This is useful for fishing purposes, partly on account of its great tenacity and partly owing to its transparent quality, the line attaching the hook when in the water not being visible. The manner of obtaining this threadlike gut is described in the Journal of the Society of Arts as follows:-After the grub has eaten enough mulberry leaves and before it begins to spin, which is during the months of May and June, it is thrown into vinegar for several hours. The insect is killed, and the substance which the grub, if alive, would have spun into a cocoon, is forcibly drawn out from the dead body into a much thicker and shorter silken thread. Two thick threads (from each grub) are placed for about four hours in clear cold water, after which they are dipped for ten or fifteen minutes in a solution of some caustic, for which purpose soft soap dissolved in water is used. This serves to loosen a fine outer skin, which is next removed by the hands while the

workman holds the thread between his teeth. The silk is then

hung up to dry, care being taken to choose a shady place, as the sun has the effect of making them too brittle afterwards. In some parts of the country these silk guts are bleached with sulphur vapour, which makes them look beautifully glossy and snow-white, like spun glass, while those naturally dried retain always a yellowish tint.

THE current number of the Annali d'Igiene Sperimentale contains a note by Dr. Casagrandi on a yeast producing a red pigment which, in many respects, resembles the one described by Demme some years ago, and isolated by him from a cheese. Demme stated that his variety was not endowed with any fermentative properties; that isolated by Casagrandi, on the contrary, ferments glucose very readily. This fermentative power is not, however, a trustworthy one for establishing differences between very similar varieties of bacteria, for, as in other cases so in this, Casagrandi has found that Demme's yeast can be induced to ferment glucose if particular precautions are adopted. Both Demme's and Casagrandi's specimens are pathogenic to guinea-pigs, rabbits and rats, when subcutaneously introduced into these animals; whilst of much interest is the fact that when grown in milk they are both capable of so modifying the character of this liquid that dogs and rabbits fed with such milk develop diarrhoea, and the same symptoms have been observed in babies which had partaken of milk in which this red yeast had been growing. This yeast appears to be present in our surroundings, and may, therefore, at any time make its presence felt by obtaining access to milk if the latter is left unduly exposed. We already have one well-recognised red yeast, the so-called Rosa hefe, but Casagrandi does not claim that his variety is anything more than an offshoot from the second red yeast, known to us as the Saccharomyces ruber discovered by Demme some seven years ago.

No. 11, vol. iii., of Spelunca contains, among much other cavern-lore, an illustrated account of M. Martel's explorations in the British Isles in 1895.

IN the November number of the Irish Naturalist, Mr. G. H. Kinahan urges the importance of a careful study of quartz-rocks, when not metamorphosed, with a view to the recognition of structures that may prove some of them to be of organic origin, like the modern sinter produced by the algae of hot springs.

MR. W. JEROME HARRISON has reprinted, from the Glacialists Magazine, "A Bibliography of Norfolk Glaciology," on the lines of his similar work on the Midlands. Over four hundred papers are catalogued, in approximate order of publication, and short abstracts of the most important are given. There is also a list of the Geological Survey maps, and an author-index. A reproduction of a photograph of one of the great chalk-masses in the drift of Runton forms a frontispiece to this useful reprint.

To commemorate the incorporation of the University College of Sheffield, a number of scientific papers by members of the College have been brought together and printed in a volume for private distribution. The subjects of physical papers included in the volume are :-The influence of carbon on iron, by Prof. J. O. Arnold; the preparation of pure iron by electrolysis, by Prof. W. M. Hicks, F.R.S., and Mr. L. T. O'Shea; vortex aggregates with gyrostatic quality, by Prof. Hicks; functions connected with tesseral harmonics, by Prof. A. H. Leahy; superheated steam-engine trials, by Prof. W. Ripper; the amount of carbonic anhydride in the atmosphere, by Prof. W. Carleton Williams; and contributions to the knowledge of the Triazole series, by Dr. George Young. In biological science there are papers on the comparative intellectual value of the anterior and posterior cerebral lobes, by Dr. C. Clapham; the development of the ovipositor in Periplaneta orientalis, by Prof. A. Denny;