prince, to Egypt, and his marriage with the sister of the queen. Besides the devices the canopy was ornamented with a hieroglyphical inscription, the purport of which appears to be that the queen in the future state was in the arms of Khonsu, one of the deities of Thebes, son of Mut and Amen," redolent with perfumes sweet as those of Punt," the present Somali or Guardafui, and "crowned with flowers." Those found in the coffins of this period, and which still preserved their original colours, have been determined to be blue larkspur, yellow mimosas, or acacias, and the white lotus, besides which, according to Mr. Stuart, a moss was discovered in the coffins resembling a kind found only in Greece. The coloured plate of the canopy which accompanies this part of the work gives an idea of the brilliancy of this remarkable piece of leather embroidery as it appeared nearly three thousand years ago. Specimens of this leather canopy, which have been brought to England, show that the colours with which it was painted or dyed still retained their original lustre. From some unknown circumstance they have, like the flowers, never paled by the effects of time.

In his commentary on the text, which it is unnecessary to follow here in detail, Mr. Stuart has given an account of the scarabæus, known as the Copris Isidis of Savigny, and detailed a fact not generally known or described in the account of that insect. Instead of propelling the clay ball or pellet or the dung cased in with clay as the other kinds of this family are said to do with their-hind legs, the male Copris Isidis carries the ball on its head and neck, for which the peculiar formations of the horns and projections of the thorax are specially adapted. One has been found wending its way over the ground with its spherical load, another has been knocked down bearing it as the beetle hummed his drony flight through the air.

Besides the description of the leather pall, Mr. Stuart gives some account of the recently discovered pyramid of Pepi at Sakkarah and that of Haremsaf. The interior of these pyramids, unlike any of the others, was covered with incised inscriptions coloured green, a peculiarity seen also on some sepulchral tablets. The inscriptions of these pyramids are mythological phrases, consisting of formulas like those of the Ritual comparing the passage of the soul of the deceased kings after death through the heavens to the movement of the constellation Orion and the course of Sothis or the Dog Star. Amongst the other new facts mentioned in these inscriptions is that of the tree of life, which is placed in the island of the blest amongst the pools of the fields of the Aahlu or Egyptian Elysium. A new light is shed on the earlier mythology by these texts, which chiefly turn on the Nut or goddess of the Ether, from whom Osiris and the monarch in the character of that god is descended. These remarkable texts have been translated by Brugsch-Bey, and Lauth. It is much to be regretted that these inscriptions are so entirely religious, and that these earliest of hieroglyphic monuments offer no contribution to the history of that remote period, Meidoum, is surrounded by tombs, in one of which the author found the name of Senofru of the 3rd dynasty. The attempts to solve the antiquity of this sepulchre from other sources has failed like all the earliest works of Egypt; for the passage is uninstructive, some scribes of a later age have scrawled or scratched a memorandum of a visit, but the walls are otherwise silent,

and the chamber has not been found in which the royal tenant was deposited. The mastabas of the age do not abound in relics, and the antiquity of some of the terra cotta vases has been impugned, the criteria of the different kinds of pottery being obscure. At Dashour the author found a very early tomb of a person named Afoua, but although the style of art announced a high antiquity, the inscriptions curt, and in the oldest form, offered no novel points of interest, they were like those of the slab of the 3rd dynasty at Oxford, supposed to have been brought by Greaves from Egypt.

Mr. Stuart has published the tomb of Rameses, the governor of Thebes, in the reign of Amenophis IV., and the so-called Khuenaten, and enters into a discussion of the difference between Amenophis IV. and the heretic monarch. The general idea is that Amenophis IV. adopted the worship of the sun's disk soon after his accession, and altered his name from Amenophis, or "the peace of Amen," to that of Khuenaten, or the "splendour of the disk," in honour of the orb of heaven, whose worship he had substituted for that of the Theban god. The fact that the features of Amenophis and Khuenaten essentially differ, the one depicted as a rotund youth, the other that of a haggard septuagenarian, had long attracted attention, and been explained on the hypothesis that the portraits of Egyptian royalty were conventional, and therefore not to be depended on, and that the introduction of the new worship had unshackled the technical details of the Egyptian artists. But who was the mysterious Khuenaten? was he an emasculated virility of the harem, or a withered senility of the Nigritic race who had ascended the throne of Egypt? Was he possibly the old queen Tii, who, ambitious of power, had assumed manly costume and, attended by a mock or daughter queen and attendant princesses, endeavoured to set up a new capital and a foreign cultus at a small but rival capital. All is mystery, the facts pointed out by Mr. Stuart of the different features which could not change with the same facility as the name, the different functionaries of the two courts, the strange and servile homage paid by the courtiers of the old heretic and perhaps impostor, the copious bribery of the novel monarchy only add to the unsolved problem, and are not the least interesting part of the work. The identity of the two monarchs as two single gentlemen rolled into one will be long contested, as even the tomb at Thebes gives the same name and titles to the erased and mutilated heretical forms of Khuenaten. Amongst his miscellaneous plates are one of the mummy of Thothmes III. in its bandages, a box of the queen Makara, and some mummies of the find at Deir-el

Bahari.

These are also known from the photographs of M. Emile Brugsch, attached to the report of Maspero. Some discussions and examples of the Indo-Germanic nature of the Egyptian language are given; but this branch of philology is a knotty point, for the Egyptian language is not of a decidedly Indo-Germanic construction, although many of the words undoubtedly have Indo-Germanic analogies.

The main interest of the work, however, centres in the monuments of the Deir-el-Bahari, especially the leather canopy of Isiemkheb. There are, however, in Egypt such an enormous mass of unpublished monuments and

inscriptions that even the Deir-el-Bahari find is not to compare with the inscriptions on the temples of Denderah and Edfu, and those of the caves of Siut.

HYDROGRAPHICAL SURVEYING Hydrographical Surveying; a Description of the Means and Methods employed in constructing' Marine Charts. By Capt. W. J. L. Wharton, R.N. (London: Murray, 1882.)

CAPT

'APT. WHARTON, who has had considerable experience in nautical surveying, having been in command of surveying vessels for. nearly ten years, has devoted his time, during the short interval he has been unemployed, to writing a work on this part of the naval profession which he modestly describes, in his preface, as an endeavour to collect together information, which has existed for years in a traditionary form amongst surveyors, for the benefit of young officers who may wish to devote themselves to surveying work in the future.

A book of this sort was certainly much needed as since the time of Sir Edward Belcher, only one treatise has been written by a naval surveyor-Capt. R. Mayne, R. N., C.B.- and we think Capt. Wharton deserves the thanks of the profession for his exertions, and we hope to see his work adopted as the text-book for instruction at the Royal Naval College.

Before however reviewing Capt. Wharton's treatise we propose to state briefly what we consider to be the requirements of a nautical survey.

The perfection of marine surveying appears to us to be the representation in a graphic form, readily understood, of the coasts and harbours of the world with their various off-lying dangers; marking distinctly the various features of high and low water lines, showing the dangers to be avoided and the channels available for navigation, placing prominently on the chart those objects on the land which serve best to ascertain the position of a ship, and subordinating all other features to these objects, so that the channels to be used, and the marks by which those channels can be recognised, are easily distinguished; as well as representing the set of the tides and currents and the errors of the compass. To execute such a survey it is evident considerable care must be bestowed in ascertaining accurately the positions of the land marks, as on these depend the whole of the work, but this accuracy need not be carried to such a degree of minuteness that it cannot be shown on the chart; for, after all, the principal object of a chart is to show the soundings; and enough care has been bestowed on the land-marks if their positions are ascertained with sufficient precision for soundings. Of course circumstances occasionally arise when, from other causes, it may be advisable to modify this arrangement, but not for the purpose of navigation.

Capt. Wharton appears to have kept these objects steadily in view in writing his work. The work commences with a description of the instruments used in nautical surveying, which, although previously given by Heather and by Simms, cannot be considered out of place, and then gives a description of marine surveying in general, afterwards entering into particulars. We regret that in the description of the sextant the important errors of centering and graduation have been overlooked.

We much commend the following remark at p. 54, too often ignored by surveyors :-"The accuracy necessary in many details of a chart depends very much upon its scale. Over-accuracy is loss of time. Any time spent in obtaining what cannot be plotted on the chart is, as a rule, loss of time."

Of course the scale on which a survey should be executed should be settled after due consideration. It is evident that an inaccessible coast, off which there is deep water, does not require the same accuracy of delineation as a coast studded with bays and harbours, or off which numerous dangers exist; or those portions of the globe little frequented by shipping the same care as the coasts of the United Kingdom. These points must to a great extent be left to the officers in charge of a survey, but the scale once settled no time should be wasted over details which cannot be shown on that scale.

Capt. Wharton's remarks on soundings are excellent. There is no doubt that this, the most important work of the marine surveyor, is very monotonous. To sit in a boat day after day, from early morn to dewy eve, marking in a book soundings and angles, with the salt from the spray drying up one's skin, and the sun blistering one's nose requires more than ordinary zeal, patience, and perseverance; and only long practice enables the surveyor to really take an interest in this work. Young surveyors should, however, remember, that every other detail is subordinate to this, and that until they can really sound, thoroughly, over a given patch of ground without loss of time they cannot be considered masters of the profession.

Capt. Wharton's remarks on obtaining latitudes and running meridian distances are excellent. We think indeed that, in the latitude, the same results might be obtained with less figures, but it is by no means easy to draw a hard and fast line.

In the remarks on tides, no mention is made of the importance of referring the result obtained to a fixed mark on the shore, nor any observation as to the diurnal inequality, and consequently the necessity of, on all occasions, when practicable, registering both day and night tides. In the Eastern Archipelago the diurnal inequality is in some places 4 to 5 feet, and in Australia the mean tide level also differs at different times. These facts appear to have escaped Capt. Wharton's notice, but probably will be inserted in another edition.

In the remarks on searching for Vigias, and ascertaining the position of a ship at sea, Capt. Wharton seems tothink accurate observations cannot be obtained, as he asserts the position of a ship to be doubtful to three miles.

On this point we must differ from him, as long experi ence has proved, to our own satisfaction, that provided the weather is fairly clear the position of the ship can be obtained to half a mile. Nor in asserting this do we rest. on single evidence, as Capt. Moriarty, R.N., C.B., in the Great Eastern, had no difficulty in picking up the end of the Atlantic cable when it had been slipped from the ship.

The fact is the great error in sea observations is due to the refraction of the horizon, but it must be borne in mind that, excepting in shallow water, this is but slight, and that it can always be corrected by observing on opposite sides of the horizon.

By taking advantage also of the bright planets passing the meridian in the day time good observations can be obtained for latitude and longitude at the same time (a great point), whilst the sun is above the horizon, as well as at sunrise and sunset, when by Sumner's method three or more stars can be combined to give the position. We admit that constant practice is required to take these observations accurately, but they can be obtained, and as it is very useful to be able to make certain of a ship's position, as often as possible, all officers should practise themselves in observing both Venus and Jupiter with the Isun above the horizon.

Whilst however not agreeing with Capt. Wharton on some few points, we think his work will be found most useful, not only for young officers taking up surveying but also as a book of reference for older surveyors, and personally feel much obliged to him for combining in one volume so many useful remarks and tables which have hitherto been only in MSS. or pamphlets.

THE HORSE IN MOTION

The Horse in Motion as shown by Instantaneous Photography; with a Study on Animal Mechanics, founded on Anatomy and the Revelations of the Camera, in which is demonstrated the Theory of Quadrupedal Locomotion. By J. D. B. Stillman, M.A., M.D. Executed and Published under the Auspices of Leland Stanford. (London: Trübner and Co., 1882.)

THE

HE above is the somewhat long title of a large and important work issuing from the well-known Cambridge (U.S.) University Press. Long as is the title, the name of the principal contributor to the volume is left unrecorded there, though indeed even a cursory glance over its contents shows how much indebted is the whole question of the mode of motion in the horse to the elaborate series of investigations of Mr. J. Muybridge. Leaving aside the anatomical and teleogistic arguments of Dr. Stillman, as contained in some hundred pages of letterpress, we cull from a postscript to the same the following interesting information, which we give as we find it in the book. Some time in 1872, Mr. L. Stanford, of Palo Alto Farm, in California, had his attention called to the very controverted question as to the action of a trotting horse, and conceiving the idea that the photographic camera might be made available to illustrate the action, he, according to the authority before us, consulted with Mr. Muybridge and induced him to undertake some experiments in instantaneous photography. Some ten years ago, a photograph taken in the space of the onetwelfth of a second was considered quite a success, and it would seem that the experiments made then by Mr. Muybridge were inconclusive. In 1877 Mr. Muybridge, however, renewed his experiments. A few pictures were taken of "Occident," a noted trotter belonging to Mr. Stanford, while he was in motion, and one of these, representing the horse with all his feet clear of the ground was enlarged, retouched, and distributed. This result was so extraordinary and so successful, that it was determined to try others on a more extended scale. It was assumed that if one picture could be taken instantaneously, an indefinite number might also be taken, and so the various positions assumed by the horse in a single complete stride could be illustrated.

|

Mr. Muybridge was authorised to procure the needed apparatus, and a building suitable to the purpose was erected on Mr. Stanford's farm. By 1878 preparations were complete, and every resource of the photographic art had been provided. Twelve cameras were placed in the building at intervals of twenty-one inches, with double shutters to each, and these shutters were so arranged that the whole series of exposures were made in the time occupied by a single complete stride of a horse. The very ingenious mechanism invented by Mr. Muybridge it would be impossible to describe without the assistance of illustrations, but it may be stated that he was thereby enabled to double the number of his cameras, and the whole of the large series of twenty-four figures each, which are used to illustrate this volume, were taken by him. They were very accurately taken, and the heliotypes are perfect transcripts of the original photographs.

Thanks to the zeal and energy of Mr. Muybridge, and the liberality of Mr. Stanford, we are now enabled to see for ourselves the various attitudes assumed by a horse in running, trotting, leaping, and the result is most strange. It would seem as if most civilised nations had failed to recognise the true action of this noble quadruped, as if all had settled down into being content with a conventional idea of how a horse in motion ought to be represented. Now our artists will have no excuse; they can directly interrogate nature, as represented to them in these silhouettes, no doubt at first they may follow her with fear, for some of the positions look strange, not to say grotesque, but soon both artist and the public will have learnt to recognise the truth: and once this is so, the old style will be in its turn regarded as grotesque, and as representing but an early stage in the development of art.

Mr. Muybridge's photographs will be of immense importance to all art students, and they should be attentively studied by all admirers of the horse. A few other photographs are given in this volume of the various stages of motion in the cow, dog, deer, and boar.

OUR BOOK SHELF

Unexplored Baluchistán: a Survey of a Route through Mekrán, Bashkurd, Persia, Turkistan, and Turkey. By Ernest A. Floyer. (London: Griffith and Farran, 1882.)

AN entertaining book of travel, but by no means an exploration of" Unexplored Báluchistán," as is indeed sufficiently evident from the sub-title. Nevertheless, Mr. Floyer has investigated and partly solved some interesting geogra phical questions in the little-known province of Bashkurd (Bashakard), on the Perso-Mekrán frontier, which he visited on two separate occasions during the years 1876-7. This region, which had been merely skirted by Goldsmid, Lovett, Ewen Smith, St. John, and others connected with the Perso-Balúch Boundary Commission of 1872, and with the development of telegraphy in Persia and Mekrán in 1873-4, was ascertained to comprise six separate territories or districts - Gavr and Parment in the east, Jagda in the west, Marz and Pizgh north and south respectively, and Daroserd with the capital, Angurhán, in the centre. The town, which appears to be a place of great natural strength, was found to lie in 26° 40′ N. lat., 57° 55′ E. long., or about thirty miles from the position Band range, between Daroserd and Pizgh, was crossed assigned to it on Major St. John's map. The Aphen-inear its western extremity, and ascertained to run east and west under 26° 30' N., at a mean elevation of 3600

feet, the culminating point of the whole province being apparently the Gu-Koh peak (6,400 feet) in the Parment district.

A survey of the Ab-washur water-parting, between Bashkurd and Hormuz Strait, considerably reduced the supposed eastward extension of the Mináb basin, and showed conclusively that it was in no way connected with the Bampur River, which many geographers have hitherto made to discharge through the Mináb into the Persian Gulf. Mr. Floyer now argues with much force that the true outlet of the Bampúr is the Sadích (Sadaich), which reaches the coast in 58° 40′ E., in the Gulf of Omán, and which seems to flow from the Shahri country, through the Shimsani Pass, in the Band-i-Marz range. He found that where he crossed the Haliri in 28° N., 57° 40' E., it was already a considerable stream, 90 feet broad, and 4 feet deep. The furthest head-waters of this important river, of which next to nothing was previously known, are in the Jemal Bariz range, whence it flows in a south-easterly direction to the Rudbar and Shahri districts. Here it would be almost necessarily joined by the Bampúr River, coming from the north-east, and the united stream, whose further course has hitherto remained an unsolved problem, would appear to flow thence through the Shimsani Pass southwards to the Sadích. Hence the Sadích would seem to be the lower course of the Haliri-Bampúr, thus draining nearly the whole of the region in south-east Persia, between 57°61° E., and 25° 30-29° N. But this interesting point cannot, of course, be finally determined without a more thorough exploration of the Rudbar and Shahri districts between Bampúr and the Ab-washur water-parting.

The work, whose chief fault is its misguiding title, is written in a pleasant, vivacious style, and contains much useful information touching the ethnical, social, and linguistic relations of the Balúchi tribes on the PersoMekrán frontier. A. H. KEANE

A Synopsis of Elementary Results in Pure and Applied Mathematics: containing Propositions, Formulæ, and Methods of Analysis, with Abridged Demonstrations. By G. S. Carr, B.A. Vol. i., Section ix. (London: C. F. Hodgson and Son, 1882.)

IN our notices of the previous sections we have sufficiently indicated the scope of this work. The present section is devoted to the integral calculus, and takes up its numbered articles at 1900, and closes at 2997: the pagination being pp. 313-440 of part ii. of vol. i. The same honest work, for which we have already commended the author, is conspicuous here, and the utility of having such a handy manual on the calculus is evident. It would be impossible to furnish here the results of a thorough examination of the text; the preparation for such a task would take up a very long time; but we would recommend a testing of the several parts to which a reader may have occasion frequently to refer, so that the book might be consulted with full confidence. We are glad to find that the likelihood of the occurrence of such errors as we mentioned in our notice of the first part, is reduced to a minimum by the very careful method of revision now adopted by Mr. Carr. We have much pleasure in commending this new section to the notice of our mathematical readers.

A Collection of Examples and Problems on Conics and some of the Higher Plane Curves. By Ralph A. Roberts, M.A. (Dublin: Hodges, Figgis, and Co., 1882.)

THESE Examples will serve as an excellent compendium of results to a student who is working through Dr. Salmon's Treatises on Conic Sections and on the Higher Plane Curves. In fact it was whilst the author was reading the above-named works that he conceived these useful illustrative exercises. Mr. Roberts shows himself to be

an apt mathematician, and to have a very extensive acquaintance with the classes of curves considered. These are mostly curves of the second, third, and fourth orders. The Problems have been, in general, suggested by Dr. Salmon's treatises and by Dr. Casey's Memoir on Bicircular Quartics: Mr. Roberts also acknowledges his indebtedness to Darboux's Sur une classe remarquable de courbes et de surfaces algébriques. Occasional explanatory matter is thrown in here and there, and concise proofs are given in several cases. As the text-books contain a limited number of examples, this work will be a useful supplement to them. We like almost everything about the book except the paper, and that appears to us to be of a very inferior character.

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. No notice is taken of anonymous communications.

[The Editor urgently requests correspondents to keep their letters as short as possible. The pressure on his space is so great that it is impossible otherwise to ensure the appearance even of communications containing interesting and novel facts.] The Recent Unseasonable Weather

IN view of the recent unusually cold weather in England and Scotland, which has been so well described and proximately explained in last week's NATURE, the following paragraph, extracted from the Standard of June 15, appears to me highly suggestive, especially as regards one of the probable causes for the "unwonted high pressures" on the northern side of the depression which is accused of being the immediate source of these unseasonable conditions:

"News from Iceland states that the Spitzbergen floe-ice surrounds the north and east coast, entirely preventing navigation. A Norwegian steamer endeavouring to reach Bernfiord, on the south-east coast, last week, was caught in the ice and had vegetation has made no progress, causing a great loss of horses to put back. Owing to the presence of these immense ice-fields

and sheep through starvation. Epidemics of measles and smallpox have been introduced into the island from Europe, and are making extensive ravages among the population; the former is especially prevalent in Rejkjavik.

Now it has been ascertained with some considerable degree of certainty by Messrs. Blanford and Eliot, the Government meteorologists in India, that a heavy winter snowfall over the Northlowering the temperature and elevating the atmospheric pressure west Himalaya exercises a marked and prolonged influence in and thereby directly affecting the winds and weather, over the whole of Northern India, and parts of Central India; and indirectly to a much greater distance. Turning to Europe, we find the distance from Rejkjavik, on the west coast of Iceland to London is about 1140 miles, or about the same as from Lahore to Calcutta (1080 miles), while from Cape Horn on the east coast of Iceland to Edinburgh the distance is only 750 miles, or about the same as from Calcutta to Agra. To any one familiar with Indian weather charts or the meteorology of that country, it would appear absurd not to attempt to correlate the meteorological conditions at places so comparatively near as the above-mentioned towns; and in fact experience has shown that the meteorology of the Punjab is not only intimately connected with that of Lower Bengal, but also with that of Southern India. If therefore it has been found that an abnormally heavy snowfall in the North-West Himalaya, such as that which characterised the winters of 1876-77 and 1877-78, exercised a marked effect on the meteorology of Northern India, which was felt at places situated 1000 miles or more from the seat of action, may it not be reasonably inferred that the presence of a large mass of ice or snow in the Icelandic area would be likely to give rise to similar atmospheric conditions over these islands? It seems therefore not at all improbable, that the abnormal weather during the past few weeks may be directly due in some considerable measure to the coincident appearance of large masses of ice off the eastern coasts of Iceland, like those which, from the account in the Standard, appear to be at present prevailing to an unusual extent.

In the case of India an abnormally heavy fall of snow in the

Himalayan zone is found to be associated, not only with the subsequent conditions already named, but also with an initially, and therefore according to experience subsequently weak southwest monsoon, which in its turn invariably causes local, if not general drought and famine. These heavy snowfalls are found to have a tendency to recur at the minimum sun-spot epochs, and are proximately due to some condition of the upper anti-monsoon current, at present not exactly known, by which a larger amount of vapour is deposited in the winter, on the Himalaya as snow, and on the North Indian plains as the "winter rains."

It does not appear that we can so readily account for the occurrence of the present ice-floes off Ireland or for the large masses which have been encountered this spring in the Western Atlantic. They must however to some extent be due to the unusually warm winter which seems to have prevailed pretty uniformly over the North Atlantic and North-West Europe, and which has detached a larger proportion than usual of the Arctic ice-fields. And though it is improbable that we shall find any such regular periodicity in the amount of these ice-floes in the Atlantic as in that of the Indian winter snows and rains, it is worthy of notice to observe that they have a decided tendency to occur to an uuwonted extent about the times of maximum sunspot-like the present. Thus Prof. Fritz, of Zurich,1 gives the following as the list of years in which floating ice was found most abundantly in the lower latitudes of the North Atlantic :Years of greatest frequency Epochs of maximum

of floating ice. 1789

sun-spot.

1788.1

1804'2

1816'4

1829 9

1837'2

1848'1

1860'1

1870.6

It is also interesting to notice that in 1862 Heis's "Wochenschrift" mentions that the floating ice-masses in the Atlantic caused "a noticeable cooling of the weather in June over Europe.' And it is further significant to find in a detailed list of the ice met with every month in the Atlantic by ships belonging to the North German lines from 1860 to 1869, that 1868 and 1869 (the year in which similar weather to the present is mentioned as having been observed by the writer of the paragraph in NATURE) were the years in which the greatest quantity of ice was encountered. Though I agree with Dr. Hann in attributing more importance to the tropical than to the polar area, in influencing the general weather of these latitudes, I think it very probable on theoretical grounds that we are relatively more influenced by the latter area in summer and by the former in winter, and that just as it has been inferred that the regular recurrence of periods of diminished temperature in Europe, is due to the regular movements of the ice in the polar area so we may reasonably conclude that abnormal movements of the ice, especially in the Spitzbergen area, are likely to produce periods of abnormal coolness such as that which at present prevails. In any case the moral to be drawn, if we really do intend to solve the weather problem, is by all means to have a meteorological station in Iceland, and endeavour to study the weather as we are fortunately able to do in India, on a large scale, instead of merely confining our attention to the minute range of conditions we are able to observe within the limited area of these islands.

E. DOUGLAS ARCHIBALD

The Analysis of the Tuning Fork

IN NATURE last week there is a short description of Mr. W. F. Stanley's well-devised experiments, by which the tuningfork "is shown not to depend upon a vibrating ventroid."

Few persons would readily obtain the experimental steel rod, or would care to attempt the feat of sawing through the bend of the fork down into the stem, and some musical readers may like to know that (missing, of course, the pretty effects) there is a less arduous way of arriving at the conclusion to which Mr. Stanley has directed attention. By very simple experiments I have been accustomed to show that Chladni's analysis, as generally accepted,

In his work, "Ueber die Beziehungen der Sonnen flecken-periode zu den Meteorologischen und Magnetischen Erscheinungen," p. 175.

is not in all particulars borne out by the evidence of facts. If a vibrating tuning fork is held in its upright position by means of a knife-blade passed through the prongs, pressing upon the inner bend so that the stem is in contact with the table, without its being held by the fingers, there will be a communication of vibra tions fully as strong as when held in the usual manner, with variation of intensities according to differences in the degrees of pressure. In this experiment the fork at its bend is subjected to pressure both above and below. The argument, therefore, is that the existence of a segment in transversal vibration, occupying the bend of the fork as figured in Chladni's analysis, is incompatible with the evidence. As in all musical instruments, the communicating of transversal vibrations from one solid to another is invariably through the nodes, and as segments are always destroyed by firm pressure, it seems clear that the analysis should be amended. If a vibrating fork is drawn across a stretched string with pressure, the prong passing from the bend towards the point or end, the integrity of the vibrations of the fork is not impaired, and there is but a slight transference of vibration to the string; but it is otherwise with respect to a stretched wire, as when the prong comes into contact with the wire, its vibrations cease; the wire will not be subordinated to the coercive activity of the prong as the string is; yet if the fork is placed with the prongs astride the wire, so that the bend, at the seat of the alleged segment, rides upon the wire, the wire readily conveys the vibrations, and acts as a sound-post. It may be shown that the stem of the fork acts likewise as a sound-post, since we may substitute a free stem; if a vibrating fork is held by the stem, and if through the prongs another fork has the shoulder of its stem pressed upon the bend, then, when the point of this second stem is brought into contact with a solid, the vibrations of the fork are transmitted through it from the bend, with nearly the strength of tone as would be produced by the original fixed stem. The stem itself may be dispensed with as a part of the system, for if the fork is held so that the external part of the bend, where it joins the stem, is pressed against the edge of a table or other solid, its vibrations are not interfered with; neither is the strength of tone diminished, except as in each of these instances, varying in the usual way according to the degree of pressure. HERMANN SMITH June 19

ALL who have watched waves breaking on the sea-shore must have noticed the furrowed or "combed " appearance of the back of a wave as it curls over. If the water is not much disturbed by wind, it is seen, on attentive watching, that this "combing" appears suddenly, and begins at the advancing edge of the crest, and spreads backwards. With small waves a foot or so in height and of long extended front, such as are seen in shallow water, it may be observed that the crest, which in this case rolls down the front of the wave, is at first smooth and even, while the back of the wave is also smooth and unfurrowed, but the edge of the crest suddenly becomes crenated, and almost simultaneously the combing appears on the back of the wave, travelling rapidly backwards from the crenated edge. Moreover a considerable length of the wave appears to be similarly affected almost at the same instant. With larger waves, whose crest falls rather than rolls upon the concave front, I have observed that the edge is at first smooth and even, but that it suddenly becomes uneven, and often fringed with a row or rows of drops, and that at the same instant the combing appears. In both cases, if there is much wind, the regularity of the phenomenon is disturbed, and observation is in other ways rendered difficult. The action is so exactly parallel to something which takes place in the splash of drops, and which I have described in detail in a paper recently read before the Royal Society (see Proc. Roy. Soc., No. 218), that I think your readers may be interested in a brief statement, with special reference to this more familiar case of waves, of the explanation there put forward. The explanation amounts to this:-It is well known that a long cylinder of liquid is unstable, and will, if left to itself, at once tend to split into a row of equal, equi distant drops; the splitting being effected by a constriction of the cylinder in certain places, and a bulging out in others. Again, if a mass of liquid is bounded by an edge whose surface is approximately a portion of a long cylinder, there is good reason for supposing that this cylindrical edge will be subject to similar laws of stability, and that it will tend to cleave in the same way, the surface being forced in in certain places, and out in others. Now a wave's crest presents such a cylindrical edge.

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