consequence of what appears to have been a chronic disease of the eyes, the poet lost his sight at the early age of about 32 or 34 years, and that he, once at least, styles himself a downright blind man, in his Hymn to Delian Apollo, ver. 169-73, which derives no mean authenticity from being so pointedly quoted by Thucydides, III., 104, and which runs thus :

ὑππότε κέν τις ἐπιχθονίων ἀνθρώπων

ἐνθάδ ̓ ἀνείρηται ξεῖνιος ταλαπείριος ἐλθών·
ὦ κοῦραι, τίς δ ̓ ὕμμιν ἀνὴρ ἥδιστος ἀοιδῶν
ἐνθ'δε πωλεῖται, καὶ τέῳ τέρπεσθε μάλιστα ;
ὑμεῖς δ ̓ εὖ μάλα πᾶσαι ὑποκρίνασθ ̓ εὐφήμως
τυφλὸς ἀνὴρ, οἰκεῖ δὲ Χίῳ ἔνι παιπαλοέσση,
τοῦ πᾶσαι μετόπισθεν ἀριστεύουσιν ἀοιδαί.

If some day an earthborn man, a wayfaring stranger,
Asks you the name of whom best you like of all the minstrels

you know,

Whose songs are, oh lasses, the most delightful to you,
Oh, then, unanimously, surely, you answer:

It is the blind man who dwells in the rocky island of Chios,
His songs are to us by far the sweetest of all.

I need not add, as a further argument, that Homer frequently was alluded to as the blind and humpbacked man, ὁ κυφὸς καὶ τυφλὸς ἀνήρ,· αnd it seems to me trifling to qualify, or mitigate, the racy juxtaposition of the two epithets.

To what extent colour hallucinations, so frequent in connection with certain forms of blindness, may possibly have impaired the poet's imaginative faculties with regard to the varying hues and shades of colour, it would be for the present, from want, for obvious reasons, of similar observations, difficult to settle. However, I cannot but think that what by some so recently has been called Homer's colour-blindness may be the natural consequence, on the one hand, of the increasing dimness of his recollections as well as owing to these optical hallucinations, and finally, to the defective chromatic terminology of his time. The following some of the Greek and Latin authors who, together with Herodotus, aver and enlarge upon the blindness of Homer :Plutarch, Vita Hom. 12; Thucyd., III. 104; Pausan., II. 33, 3; III. 4, 33; Lycophron, Cassandra, 422; Aristot., Orat., L. P. 703; Cicero, Tuscul, V. 39.

are

I refrain from discussing the question whether, from a physiological point of view, such a profound functional perturbation as is involved in the term of colour-blindness, viz., deficiency in the perception of any plurality of colours in the spectrum, would not seem to be symptomatical of most momentous organic disturbances in the nervous apparatus of the eye, generally conducive to the most hopeless forms of blindness.

Scientific Club

J. HERSCHEL

In reading Mr. Pole's article on Homer's sensations of colour, there is one point which seemed to me to call for explanation. Mr. Pole says that in the solar spectrum he sees only two colours, blue and yellow, and that the red space appears to him yellow. From this one would naturally infer that the whole of the spectrum visible to ordinary persons is visible to him also, but that it presents only these two colours, which graduate into one another without any break, and that the green space appears as yellow. And with a colour-blind person who has allowed me to test his capabilities, I found this actually to be the case. But later on Mr. Pole says that pure red and pure green appear to him not yellow but grey. I would wish, then, to ask Mr. Pole whether the spectrum presents to his vision, in place of the green, a neutral space or an interval of darkness? In other words, have the rays of that particular refrangibility no action at all upon his retina, or is it that they have no action peculiar to

I

The very word of"Ομηρος signified "blind" in the vernacular idiom of Κύμη, or Cumæ, one of the Æolian colonies in Asia Minor, where he lived for some time, and, as will be shown anon, accidentally came by the name of Homer, his original name being Melesigenes, from his happening to be born on the banks of the small river Meles, which flows by Smyrna and runs into the Smyrnian sinus.

themselves, but simply produce the general effect of light? In either case the phenomenon seems more anomalous than if he saw all colours as colours, though he could only class them under two heads. To take a familiar analogy, it is as if a man should be perfectly able to distinguish the pitch of notes at either end of the scale, but the notes between should either not affect the auditory nerve at all, or should affect it simply as noise. Pembroke College, Oxford FRANK PODMORE

Anthropometry

As I have stated in the preface that my object in publishing my "Manual of Anthropometry" is to invite criticism with a view to perfecting the anthropometrical chart which it contains, and which forms its chief feature, I may be excused for referring to the notice of the work which appears in NATURE, vol. xix. p. 29. The reviewer objects to the large number of measurements given in the chart, but he has overlooked my statement that many of them are of a secondary character, and that I leave the student liberty to select the measurements which best suit his purpose, requiring only of him that they shall be made and recorded in a uniform manner, and thus become the common property of statisticians. Anthropometry can make no progress as a science, so long as observers are at liberty to make the same nominal measurement of the body in four or five different ways, as is the case, for instance, with chest-girths.

I may add that my manual was not written for the three or four individuals in this country who have mastered the "theory of human proportions" as a mathematical curiosity, but for army surgeons, busy medical men, schoolmasters, and others who are much more concerned with actual facts than theories of probabilities. CHARLES ROBERTS Bolton Row, W.

Divisibility of Electric Light

In all communications on this subject in NATURE and elsewhere, the division of light is considered only with reference to parallel circuits, and this naturally causes great loss of light by the law that heating is proportional to the square of the current. But in electric circuits their resistance has always to be considered; and if two lamps are taken parallel, only half the resistance of the one lamp is obtained, and such resistance can be obtained by taking two parallel circuits of two lamps in series in each; the light obtained then is one quarter in each lamp, as half the current is flowing through each circuit, and as four quarters make a whole, no loss of light is caused by division in such a method of one current to any number of lamps. There are certainly practical difficulties in the way of burning lamps in series, though these are greatly diminished if incandescent wire is used as the light-emitting source. However, there is no inherent reason why the electric light should be wasteful in division, as is described_by Mr. Trant. F. JACOB

Verification of Pervouchine's Statements regarding the Divisibility of Certain Numbers

THE statements of Pervouchine, reported in some recent numbers of NATURE, are equivalent to the following:-That the 210 power of 16 is less by I than some multiple of 7 x 214 + 1; and the 221 power of 16 is less by I than some multiple of 5X225 + I.

Letr be the remainder after dividing the 2n power of 16 by one of the above divisors. Then since the 2+1 power of 16 is the square of the 2a power, n+1 differs from the square of rn by a multiple of the divisor; or +1 is the remainder arising from the division of the square of rn.

Use for the work the scale whose radix is 16. In this scale the above divisors are

I 1200ΟΙ and 1000000 I.

In the first case, calculating on the plan indicated, we find the

Herodot. Halic., vita Hom., 2, 13.

5 10 5

7

11 14 2 14 4

2 15 9 I

10 11 2 15 14 7 I

4 12 I 5 4 12 90

I II

7 4 3 1 7, 4 10 4 11 13 0 0+ 9011 76 16-4 6 6 11 8 8 11

The last four lines of the work are made up thus:-In adding the parts of the square depress the last six places to line 2, leaving the rest in line I; then proceeding to the extreme left, carry the tens figure, in this case o, six places to the right, for subtraction into line 3, and depress the units figure (5) into line 2. Multiply the just depressed figure (5) by 16, and add to it what is found (10) in the place to the right of it in line I (giving 90); again carry the tens figure (9) for subtraction into line 3, and depress the units figure into line 2; repeat the process, moving to the right, until line I is exhausted; then the difference between line 3 and the last seven places of line 2 gives line 4, the result required.

For the sake of safety, before proceeding to calculate 17, calculate re again from the complement of re with reference to the divisor, in this case from + 7 13 5 6 6 13. If the same result is again obtained, you may go on confidently. Hampstead JOHN BRIDGE

Vulcan and Bode's Law

In the year 1778-just a hundred years ago the astronomer Bode published an approximation to a law respecting the planetary distances. He took the numbers

0, 3, 6, 12, 24, 48, 96, 192, 384,

1, 4, 7, 10, 16, 28, 52, 100, 196, 388,

if I represents the mean distance of the Vulcan-asteroids, and 28 that of the Ceres-asteroids, it is a fact that after the first ring come four planets, Mercury, Venus, Earth, Mars, and after the second ring four planets, Jupiter, Saturn, Uranus, Neptune, the two sets of planets having marked differences as regards axial rotation and density.

What, then, is beyond Neptune? The law seems to say, a ring of asteroids at an average distance of 772. The motion of Neptune does not lead astronomers to suspect a planet beyond. Perhaps the optical instruments of the future may help to answer this question, Is there a ring of asteroids beyond Neptune? B. G. JENKINS

4, Buccleuch Road, Dulwich

Irish Bog Oak

Can you or any correspondent kindly give me the scientific name of the Irish "bog-oak" (fossil)? It should be either Quercus pedunculata or Q. sessiliflora, the existing species, but though I have seen many specimens, I never got hold of one which would enable me to determine the species, and, for aught I know, there may be some of both. W. F. SINCLAIR 46, Guilford Street, W.C.

OUR ASTRONOMICAL COLUMN

THE TOTAL SOLAR ECLIPSE OF JANUARY 11, 1880.The central line in this eclipse ends soon after reaching the coast of California, where it is possible totality may be witnessed close upon sunset. Tracing the previous path of the shadow through its long course across the Pacific with the aid of the Admiralty chart, it will be found that the only islands included within it are the Coquille, Bonham, and Elizabeth Islands, lying near together, between 169° and 170° E. longitude, and belonging to the Marshall Islands group. The eclipse passes centrally over the largest of the Coquilles, as laid down in the Admiralty chart of this group, according to a calculation in which the moon's place has been made to accord very nearly with Hansen corrected to Newcomb, which gives the following track :

each after the second being double the preceding; to these he added 4, giving 4, 7, 10, 16, 28, 52, 100, 196, 388,

So that the breadth of the shadow in the direction of the meridian does not exceed 33'. Reading off from the chart, it will be found that the centre of the largest of the Coquille Islands is in about 169° 35'5 E. and

3.8, 72, 10, 15°2, (27), 52, 95.3, 1918, 300.3.

The publication of this law, at a time when the asteroids between Mars and Jupiter were as yet undiscovered, drew attention to Kepler's speculation that a planet was wanting between Mars and Jupiter. Twenty-one years after Ceres, the first of the

pears that the total eclipse will commence at 8h.41m.255. A.M. on January 12, local mean time, and continue Im. 16s., and this represents the most favourable condition under which the eclipse can be observed on land. For any other point within the shadow in this vicinity the duration of totality may be determined by the folwich mean time of beginning or ending, according as the upper or lower sign is employed :

TRANSITS OF MERCURY.-Prof. Holden has published an "Index-Catalogue of Books and Memoirs on the Transits of Mercury," which he had prepared to aid him in a search for records of the physical phenomena which have been observed at such transits. The list is not quite a complete one, the publications of observatories not being included, but there is little inconvenience in the omission, as such observations and memoirs can be found by reference to the volumes for transit years, and Prof. Holden gives a list of the dates of all the transits of Mercury so far observed. Catalogues of this description must prove most serviceable to the student and to every one who has occasion to consult the general literature of an astronomical subject, and we hope the American astronomer may find leisure to continue them. Reference has already been made in this column to his very valuable "Index-Catalogue to the Literature of Nebulæ and Clusters," &c., forming No. 311 of the "Smithsonian Miscellaneous Collections." The publication above mentioned forms No. I of "Biographical Contributions," edited by Justin Winsor, Librarian of Harvard University. The copy before us is republished from the Bulletin of the library for October, 1878.

BIELA'S COMET AND JUPITER IN 1794.-It will be remembered by those who may have interested themselves in cometary astronomy, that between the first appearance of Biela's comet in 1772, and the next return at which it was observed, in the latter part of 1805, the elements had undergone alterations of a magnitude that occasioned doubts as to the identity of the comets, notwithstanding the general similarity of orbits, Bessel pronouncing against it, while Gauss pointed out that more than one revolution must have been accomplished

in the interval, so as to admit of the comet having approached one of the larger planets and thereby experienced perturbation to account for the differences in several of the elements. The disturbing body is now known to have been the planet Jupiter, and there has been no difficulty in fixing the epoch when the comet's motion was most deflected, but we do not recollect to have seen the particulars of the near approach of the two bodies stated in any astronomical work. Starting from the final elements for perihelion passage in 1806, determined in the masterly investigation of the late Prof. Hubbard of Washington, it appears that neglecting planetary perturbation in the interval, the comet would have made its nearest approach to the planet at the beginning of June, 1794, when their distance was less than 0.47 of the mean distance of the earth from the sun. The following distances have been similarly obtained :

embryologists. The life-history, however, of the gallmaking species belonging to the Pemphigine has baffled the skill of observers more than that of any other group. Mr. Riley is about to publish some new biological discoveries relating to this family of insects, in connection with a descriptive and monographic paper by Mr. J. Monell, of the St. Louis Botanic Gardens. The paper laid before the Association simply records some of the yet unpublished facts discovered. All of the older writers, in treating of the different gall-producing Pemphigina of Europe, have invariably failed to trace the life-history of the different species after the winged females leave the galls, and, with few exceptions, have erroneously inferred that the direct issue from the winged females hibernates somewhere. The most recent production on the subject is a paper published in the present year in Cassel, by Dr. H. F. Kessler, which is entitled the "Life-History of the Gall-Making Plant-Lice, affecting Ulmus campestris." The author, by a series of ingenious experiments, rightly came to the conclusion that the insects hibernate on the trunk, but he failed to discover in what condition they so hibernate. Led by his previous investigations into the habits of the grape Phylloxera, Mr. Riley discovered, in 1872, that some of our elm-feeding species of Pemphiginæ produce wingless and mouthless males and females, and that the female lays but one solitary impregnated egg. Continuing his observations, especially during the present summer, he has been able to trace the life-history of those species producing galls on our own elms, and to show that they all agree in this respect, and that the impregnated egg produced by the female is consigned to the sheltered portions of the trunk of the tree and there hibernatesthe issue therefrom being the stem-mother which founds the gall-inhabiting colony the ensuing spring. Thus the analogy in the life-history of the Pemphigina and the Phylloxerinæ is established, and the question as to what becomes of the winged insects after they leave the galls is no longer an open one. They instinctively seek the bark of the tree and there give birth to the sexual individuals, either directly or (in one species) through intervening generations.

LEAF ABSORPTION IN PLANTS.-The earlier experimenters on this subject, M. Perault, to wit, and Hales (1731), were persuaded that leaves absorbed dew and rain. For over a century the investigations of others supported this view, until M. Duchartre, in 1857, from his experiments, advanced a contrary opinion-that now held by most vegetable physiologists, and commonly taught in our schools. But, strange to say, gardeners, in their every-day operations, adopt a different notion from that prevailing in science. The subject has recently received the attention of the Rev. G. Henslow, who, in a paper read before the Linnean Society (November 7), shows that, while it may be true that, as Duchartre has said, dew is not absorbed by saturated tissues at night; yet, on the contrary, his (Henslow's) experiments go to prove that absorption does take place at and after sunrise, when transpiration recommences, and an indraught is caused by the moisture, wherever lingering on the leaves. He further corroborates M. Boussingault's late assertion, that, when leaves are purposely or naturally killed by excessive drought, they then do absorb water, as proved by the balance, or otherwise.

BRITISH NEWTS. From an article by M. Ferrand Lataste in the last volume of the Journal of the Société Zoologique de France, it appears that the supposed fourth species of British newt-Gray's banded newt (Ommatotriton vittatus) of Mr. Cooke's "Our Reptiles"-may be altogether removed from the British catalogue. It was first introduced into the British list by Jenyns, in 1835, on the faith of some specimens found in a bottle in the

British Museum by the late Dr. Gray, which, being associated with some British newts, were supposed to have been obtained in the neighbourhood of London. Through a somewhat similar error, some specimens in the collection | of the Jardin des Plantes at Paris were believed by Valenciennes to have been obtained in France, near Toul, and other examples were supposed to have been found living at Antwerp. It has thus come to pass that naturalists, copying one from another, have assigned "England, France, and Belgium" as the locality of this newt. It now turns out, from M. Lataste's researches, that all these localities are erroneous, and that the so-called Triton vittatus is no other than the Triton ophryticus of Berthold, an Eastern species of newt which is found in Syria and Asia Minor. The British newts are now, therefore, reduced to three in number-the crested newt (Triton cristatus) and the smooth newt (Triton taniatus), both of ordinary occurrence, and the rarer palmated newt (T. palmatus).

SPERM WHALES ON EUROPEAN COASTS. - Prof. Turner, of Edinburgh, has been collecting and investigating a number of rare prints of sperm whales stranded on European coasts at the end of the sixteenth and beginning of the seventeenth centuries. One of these illustrates a whale caught in the port of Ancona in 1601, 56 feet long, 33 feet in girth; the scene is an active and lively one, representing a landscape, fishing-boats, men engaged in cutting up the whale, spectators, &c. The Netherlands seem to have had numerous specimens stranded. These, like those occasionally visiting the Scottish coast, are all males, which, when fully grown, appear to go singly in search of food. Other whales, as cachalots, visit the south in larger numbers. Over thirty cachalots, mostly females, were stranded in 1784 in the Bay of Audierne, department of Finisterre; and a school visited Citta Nuova, in the Adriatic, in 1853.

AMERICAN JURASSIC DINOSAURS. - Prof. O. C. Marsh publishes in the current number (November) of the American Journal of Science and Arts the principal characters of some new species of dinosaurs. On the flanks of the Rocky Mountains a narrow belt can be traced for several hundred miles, which is always marked by the bones of gigantic dinosaurs. The strata consist mainly of estuary deposits of shale and sandstone, and the horizon is clearly upper Jurassic; the dinosaurian remains in this series of strata are mostly of enormous size, and indicate the largest land animals hitherto known. One new species (Atlantosaurus immanis) must have been at least eighty feet in length and several others nearly equalled it in bulk. With these monsters occur the most diminutive dinosaurs yet found, one (Nanosaurus) not being larger than a cat. Some of these new forms differ so widely from typical dinosauria that Prof. Marsh has established a new sub-order to receive them, called Sauropida, from the general character of the feet. They are the least specialised forms of the order, and in some of their characters show such an approach to the mesozoic crocodiles as to suggest a common ancestry at no very remote period. In them the front and hind limbs are nearly equal in size; the feet are plantigrade with five toes on each foot. The carpal and tarsal bones are distinct; the precaudal vertebræ contain large, apparently pneumatic cavities; the sacral vertebræ do not exceed four, and each supports its own transverse process. The pubic bones unite in front by a ventral symphisis; the limb bones are solid. One of the species described and partly figured in Prof. Marsh's paper is called Morosaurus grandis; when alive it was about forty feet in length; it walked on all four legs, was probably very sluggish in its movements, and had a brain proportionately smaller than any known vertebrate.

ZOOLOGICAL STATION AT TRIESTE.-It may not be generally known that the University of Vienna in addition

to having a zoological establishment in Vienna, has also founded a zoological station on the borders of the Adriatic Sea at Trieste. The general director of both is Prof. Dr. Claus. The assistant at Vienna is Dr. C. Grobben, and the inspector at Trieste is Dr. Ed. Graeffe. As a first fruits of these two excellent establishments Prof. C. Claus has published Part I of a handsome 8vo volume entitled "Work Done at the Zoological Institute of the Vienna University and at the Zoological Station in Trieste." The work done consists of I. A very exhaustible memoir, by Dr. Claus, on a new species of Halistemma (H. tergestinum), with remarks on the minute structure of the Physophoridæ. This memoir is illustrated by five folding plates. 2. Contributions to our knowledge of the male reproductive organs in the Decapod Crustacea, with remarks on their comparative anatomy as compared with the same organs in the rest of the Thoracostraca, by Dr. C. Grobben, with six folding plates. 3. On the origin of the nervous vagus in the Selachians, with special regard to the electrical lobes in Torpedo; this is illustrated with woodcuts and one plate. The University of Vienna and Prof. Claus are indeed to be heartily congratulated at these first results from their

new institution.

GEOGRAPHICAL NOTES

AT the meeting of the Royal Geographical Society on Monday last, a paper on "Usambara, East Africa, and the Adjoining Country," was read by the Rev. J. P. Farler, who has spent the last three years there in connection with the Universities' Mission. Usambara is described as the Switzerland of Africa, and forms a link in the great East Coast range, which extends from Abyssinia to Natal; roughly speaking, it lies between S. lat. 4° 20' and 5° 25', and E. long. 38° 20' and 39° 10'. The mountains form four detached lines running due north and south, and rising in the higher peaks to about 6,000 feet above the sea-level. The range was evidently thrown up by volcanic action, and consists of granite mixed with spar, with sandstone in the lower spurs containing plumbago. Mr. Farler describes the scenery as varied and beautiful, now soft valleys and hill-sides with hanging woods, now again wild ravines with precipitous cliffs of bare granite. Usambara is drained by four rivers: the Zigi, with its affluent, the Kihuwi, the Mkulumuzi, the Ukumbini, and the Luari, the two firstnamed emptying into Tanga Bay; none of the four, however, are navigable. Trees are found in the region in great variety, but mostly of stunted growth; euphorbias, fan-palms, and mimosa thorns are seen everywhere, and occasionally baobabs, tamarind-trees, and clusters of the Borassus palm; there is also a kind of wild palm-tree. Various animals are found in the Mjika, or wildernessantelopes varying from the size of a cow to that of a small goat, gazelles, lions, leopards, hyænas, and large apes. Mr. Farler mentions a noteworthy peculiarity in regard to the River Mkulumuzi, which in the rainy

season becomes a torrent: "The stream has cut a deep bed for itself in the granite sides of the mountain, and exploring this bed in the dry season, I have found perfectly round, well-like basins in the rock, varying from a foot in diameter and depth to 10 feet in diameter, and from 8 to 12 feet in depth. There is always a stone at the bottom of these basins, and they must have been formed by the torrent giving, during the rainy season, a rotary motion to the stone." The soil throughout Usambara is a red disintegrated clay upon a granite and sandstone foundation, and covered with a rich vegetable loam; the bottoms of the valleys contain beds of alluvial clay. Probably no more fertile soil could be found in the world, and it is capable of producing every tropical plant. The flora of the region is extensive; in the forests are found ebony, copal, teak, acacia, the india-rubber tree,