Imagens das páginas
PDF

minute survey, crept away about 7 or 8 ft. off and sat down wkh its back to the snake. The other cat, a white one, now caught sight tif the strange object, and, in a like stealthy manner, advanced to within a few inches of the gauze, and was in the act of examining the cobra, when my friend, to see the result ot a suIden sound—for up to this time we had both been still as mice—moved hit feet on the gravel. Had the effect been due to electricity, it would not hare been more instantaneous, nor more startling. At the first grate of the pebbles the white cat flung himself backwards, tumbling—to use expressive terms— 'heels over head" and "allofaheap "for about a couple of yards; whilst the black cat shot vertically upwards to somewhere near four feet in height, the impulse given by the spring of his hind legs being sufficient to throw these and his tail higher than his head.

Now both these cats are tame, and bold to such a degree that they reign supreme over all thj dogs in the house, so that thetr great timidity on this occasion was evidently due to a perception of danger. I have since found, however, that all snakes are not equally feared by them. They will let the harmless green tree snake (Fasstrtia mycterizans) twine round them without showing any signs of repugnance, and soaie other harmless snakes receive but little notice fro n them. Why is this? Is it that the hood of the cobra renders it so frightful an object, or have the cats in their nocturnal wanderings been struck at by cobras? Such is possible, for we know that in nine cases out of ten the strike is made without intention to exert the deadly power of the fangs. I believe indeed that unless irritated by an attacking enemy, or to secure active prey such as rats, &c, the cobra never strikes viciously. Experience of the ease with which ill fangs are drawn an i its helplessness without them would teach it to be careful of them.

Mangalore, Sept. 17 E. H. Pringle

Earthquake in New Guinea

When crossing the main land of New Guinea, from theG;elvinks Biy in the north, to the south coast, I slept on the night of the 12th to the 13th of June, 1S73, in the swamps of the MacCluer Gait (famous for trie murder of some of the crew and the ship's-doctor of H.M.S. Panth-.r and Endeavour, Capt. MacCluer, ia 1791, and by the attack on Signor Cerruti, the Italian traveller, several years ago). About 2 A.m. ol the 13th I awoke, in consequence of a rattling noise like that ol gun-shooting. I roused my six Malay companions, who slept around me in a small native prouw, seized my guns, and listened to what would follow. But nothing happened. It was unintelligible to me what had been the cause of this noise, the natives of these parts having no guns, so far as 1 knew, and even il they had intended an attack, would not announce then' arrival by firing their guns, instead of approaching in silence. Oa the other hand, when sleeping in a virgin forest like that which bordered these swamps, crashing noises from falling trees and from animals breaking down rjtten branches often occur, but never so many together.

Nothing more being heard we fell asleep again. At about 4 A.M. the same thing happened once more. 1 remained awake. At dawn the Papooas, whom I had brought with me from the north coast—ten men—came back to my resting-place ; they had left me, to sleep apart, had heard the noise, but could njt understand it cither.

When on the 13th I came back to Papooan houses at the River Takasi, which falls into the MacCluer Gulf—a mimi'e description of which will be published very soon in " Petcrmann's Mitlheilungen "—I heard the account of a heavy earthquake, which had taken place the night bef ire ; this of course explaining the noises we had heard: many trees having broken down at the same moment in consequence of the movement of the grjund. We did nat fee! the earthquake in our small boat, because it lay entirely in the swamp, which had not propagated the shock.

On the 1SU1 I was back at my little schooner, which was at anchor in the Geelvinks Bay, near a place called Passim. The earthquake had been felt here at the same time, accompanied by heavy underground thunder, and I could make out that thedirection had been N.W. to S.E.

After some days I came to a place just at the foot of the so much spoken of Arfak Mountains, called Audai; the earthquake had been heavy here, and even more shocks were felt on the following day. The direction had been W. E. Several native houses, built on very high poles near the slope of a hill, were

destroyed, the Papooas (Arfaks) still frightened and of opinion that the earthquake had been " made" by their enemies, another tribe on the mountains.

But in the Bay of Dorey, which has so often been visited by expeditions to New Guinea and by naturalists, where I arrived a fortnight later, the shocks appeared to have been the heaviest. All the Papooas in the different settlements there were living on shore in small shelters or huts, hastily erected, whereas they are known always to live in those large houses on the water s> often described. Several of these large houses had broken down, and the natives were still very much frightened ; they would not remove into their houses on the water. On the island of Manaswari (Vtansinam), in the Bay of Dorey, the seat of a missionary, the shocks had been from S.W. to N. E. I afterwards sought information about the extent of this earthquake, and male out that it was felt at Amberbaki, on the North coast of New Guinea, at Salwatti, the island in the North-west, and on the island of Tobie, in the east. The centre had been undoubtedly 01 the Arfak Mountains. Light earthquakes sometimes occur in New Guinea, heavy ones seldom. The destruction by the last heavy one in 1S64 could even be seen by me in 1873 along the seashore from Dorey to Wariab, and up the Arfak Mojntains, in the south of the bay of Dorey. Volcanic eruptions in these parts are not known or recorded from earlier times. But one of the tops of these mountain chains bears in the native language the name of "Fire Mountain," and some of my hunters pretended to have seen on one of their excursions (some thousands of feet high) the ground split open quite fresh, in consequence ot the earthquake, as they believed.

This earthquake has not been felt in Halmabeira and the Molukkos Islands, where shocks occurred some weeks afterwards, so that the convulsions, referred to above, appear to have been local ones in New Guinea. Dr. A. B. Meyer

Sensitive Flames at the Crystal Palace Concerts

Last Saturday, Jan. 31, at the Crystal Palace, while Mr. Vernon Rigby was singing Beethoven's "Adelaida," I heard what I thought was strangely out of place—an accompaniment to the song played on the highest notes of a violin, sometimes closely following the air note for note, at other times being onethird lower. I soon found that this proceeded from one or two sensitive gas jets, notwithstanding they were at the end of the winter concert-room farthest away from the orchestra. The very perfect manner in which they responded to every note, no matter how piano, was curious.

It happened that the gas pressure had just been increased. Had this occurred earlier the effect of Mdme. Normin-Neruda's fine performance of Mendelsohn's violin concerto would have been totally destroyed, as far as regarls a large part of the audience. This shows that it is a matter of no snnll importance in a concert-room to have the size and number of the gasburners properly proportioned to the gas supply.

King's College, Feb. 3 W. N. Hartley

THE PHOTOGRAPHIC SOCIETY

THE metropolitan photographic journals contain evidence that th2 Photographic Society of London is menaced with revolution or dissolution. If both were to befall it, the interests of Science would hardly suffer,since a more singularly inefficient organisation, under the guise of a scientific body, it would hi difficult to find, or one whose results in the scientific world are so trivial.

It is difficult indeed to conceive that a society into whose hands, fautc dc mieux, the recognition and fostering of research in so important a branch of science as photography has fallen, should have done absolutely nothing for so many years but organise itself into a pocket borough in the direction of which no man of eminent scientific capacity takes part; which not only has no scientific reports or even investigations, but seems to care only to make of itself a weak mimicry of an ar; club the chief objects of which are to prove that a photographer ought to have a chance for the Royal Academy, to discuss the most effective style of getting up portraits to revive the trade demand, and to discuss such questions as to whether portraits may be re-touched or not, and whether the printing of a photograph from a half-dozen negatives, more or less, is to be regarded as a work of design or not.

It is not sufficient to put the names of two or three wellknown men of science on the council of a society if the society show no care for science; and if the Photographic Society can do nothing more to merit the nominal position which it holds (without filling it), it is time that it should retire and give place to another. Photography has now become one of the most important aids to research in many fields of Science; every new discovery which shall develop this assistance and make its efficiency more complete is of importance to the whole world—of an importance which makes it almost incredible that the Photographic Society should not only take no part in the investigations which would lead to discovery, but should never even take recognition of them even when made, while the petty jealousies of the dominant clique have driven out of the society most of the really capable and successful investigators who have ever been in it. If the efforts at reform now being made should lead to success and the society become what it should be, a scientific body, so much the better; but if not, it is time that some new organisation should be formed to take in hand seriously the exploration of the still untried fields of chemical research, and make Photography a real branch of Science, and not deal with it merely as an amusement or a trade.

ASTRONOMY IN THE ARGENTINE CONFEDERACY TAR. GOULD, the director of the new Observatory in ■*--' the Argentine Confederacy, continues to send encouraging accounts of the progress of the great astromical works that he has there undertaken. Having laboured to determine accurately the relative brightness of all the stars in the southern heavens visible to the naked eye, he announces that a few weeks will enable him to begin the preparation of this work for publication. Great care has been taken to make a thorough and accurate comparison of the results of the four assistants, and the rule has been to determine the brightness of all the stars down to the 73 magnitude, in order to make sure of losing none as bright as the seventh.

The labour ot the Uranometry was undertaken before the arrival of the large meridian instrument, and as soon as the latter was established (namely, on Sept. 9, 1872), the observations of the zones of all stars as bright as the ninth magnitude were commenced in earnest. Each night three zones are observed whose lengths average about one hundred minutes, the entire observations for the year occupying at least eight hours. The weather is described as having been exceedingly unfavourable for astronomical work during the winter and early spring, until March, April, and May of the present year, when magnificent opportunities were enjoyed. Dr. Gould states that he has observed in all during the p.ist year about fifty thousand stars, and considers that somewhat more than half of the work of observing is already finished.

Astronomers, however, know how great a labour of computation still awaits Dr. Gould and his assistants before his results can be put into that form which is most convenient for use. The photographic work undertaken by him at his own private expense has been prosecuted with all the success that could be expected with a broken lens. Finally, however, he concluded to bespeak another object-glass, which will be purchased for the use of the observatory; and the new lens having arrived in perfect order, he hopes before long to be able to resume his labours under better auspices.

The Cordoba Meteorological Bureau, established [at his urgent representation by the national Government,

has been organised and brought into working condition as rapidly as was practicable ; but as the instruments were necessarily ordered from foreign countries, not more than half of them had arrived at the latest advices. Dr. Gould has, however, had the gratification of finding :»o gentlemen who have each carried on an uninterrupted series of observations for some dozen years past—one in Buenos Ayres, and the other near the Patagonian frontier —and he has secured the co-operation of about nfiKB correspondents. The programme issued for the instruction of his observers differs apparently but little from that of the Smithsonian Institution, the hours of observation being seven, two, and nine, local time.

[merged small][graphic][graphic]

Fig. 63. Fig. '!».

Fir,. 63.—Muscles of the Right Side of the Tongue, i. stylo-glor-a; ;,

stylo-hyoid ; 3, stylo-pharyngcus; 4, hyo-glossus; e, gemo-hywd: «.

gemo-elnsMts; 7. lingualis. Fig. 64.—Head of the Frog Phytlomedusn, showing the tongue fueJ in

front, but free posteriorly.

or tongue-bone. The tongue-bone of the frog 15, as we have seen, relatively far greater than is that of man, and the same may be said-lor the muscles attached to it> since we have no less than four muscles descending from the skull, and implanted into it, on each side. _ This fact might well be supposed to bear direct relation to the size and mobility of the frog's tongue. Th« organ in the frog and toad is singularly different from the tongues of most familiar animals, in that it is not free and moveable in front, but behind. These Batrachians take their food by suddenly throwing forwards, out" of the mouth, the free hinder end of the tongue. The inscr.t or other small animal struck by it, adheres to it, on account of a viscid saliva with which it is coated. The prey is then suddenly drawn into the mouth and swallowed.

Here then is a ready explanation of the development of the os-hyoides and its muscles. There is a difficulty however in that two toads already described, the Pips and the African form Dactylethra (Figs. 11 and 12), have no tongue whatever.

Moreover, there is another toad {Rhiuophrynus) which is even more exceptional in its order than these two; in that its tongue is not free behind, but, like that of ordinary vertebrates, in front (Fig. 13.)

The fact is, that the large tongue-bone of these animals serves, with the muscles attached to it, as much to facilitate respiration as nutrition.

It has already been said that the frog has no ribs by the elevation and depression of which it may alternately fill and empty its lungs. Neither does it possess that transverse muscular partition, the diaphragm, or midrif, which in man's class is the main agent in carrying on that function.

The lungs of the frog are inflated as follows:—The mouth is filled with air through the nostrils and kept shut while the internal openings of the nostrils are stopped by the tongue, and the entrance to the gullet is closed. Then, by the contraction of the muscles attached to it, the os-hyoides is elevated ; and every other exit from the mouth being closed, except that leading to the larynx, air is thus driven down the glottis into the lungs.

* Continued from p. 189. •

Thus for pulmonary respiration it is necessary to the frog to keep the mouth shut ; and in this way, but for the action of the skin, the animal might be choked by keeping its mouth open.

It has been already stated that the typical segmentation of the limbs is wanting in all fishes, but present in all Batrachians that have limbs at all. Similarly in all Batrachians that have limbs at all the muscles of those* limbs have essentially and fundamentally the same arrangement as in higher animals. In the higher animals, as in man, the muscles of the limbs belong to different categories named from the kinds of motion to which their contractions give rise.

Thus, when two bones are united by a moveable joint (as the thigh-bone and shin-bone) muscles which, by their contraction, tend to make the angle formed by such bones

[graphic]

Fig. 65.—Deep muscles of cxor surface of Frog's hind foot. (Tiic numbers indicate the digits to which the muscles belong.—No. I indicating the first digit or great too). ai<, abductors ; nd. adducli T ; fb, flexor brcvis; fp, flexorcs profurdi; /ph. flexorcs phalangium; op, kopponens muscles: tm, transverse muscles.

acute are termed "flexors.'' Those, on the contrary, which tend to open out such an angle are termed "extensors."

In the forearm of man, and allied animals, there are muscles which tend by their contraction to place the hand in a position either oi pronation or of supination.

When the arm and hand hang down, the palm being directed forwards, the position is that of supination, and the bones of the firearm are situate side by side.

When the arm and hand hang down, but the back of the hand is turned forwards, the position is that of pronation, and the radius crosses over the ulna. When we rest on the hands and knees, with the palms to the ground, the forearms are in pronation.

Muscles which tend to place the forearm and hand in the position of pronation are termed pronators; those which, by their contraction, tend to render it supine are called supinators.

It is somewhat surprising to find in an animal so nearly related to fishes as Menobronchus definite flexors, extensors, pro- and supi-nators essentially like those of

higher animals ; and these distinctions once established, persist up to man himself with increasing complications.

The muscular conformity between the highest and lowest of typically-limbed vertebrates is strikingly shown by the structure of the thigh and leg, the leading muscles of these parts in the frog being so like those of man that the practice of calling them by the same name is abundantly justified.

The perfection of man's hand has been justly the theme of panegyric, esteemed as widely as it is known. The delicacy and multiplicity of the motions of which it is capable are of course greatly due to the number and arrangement of the muscles with which it is provided.

One of the most important of these motions is that of the thumb as placed in opposition to the fingers, and effected by a muscle termed opponens pollicis.

An "opponens" muscle is one which passes from the bones of the wrist to one or other of the bones of the middle of the hand called metacarpals, and the opponens pollicis passes of course, as its name implies, to the metacarpal of the pollex or thumb.

No other finger of man's hand is furnished with such a muscle except the little finger, which possesses an opponens minimi digiti, passing from the wrist to the fifth metacarpal. The same condition obtains in the apes, though in them the opponens of the thumb is smaller and weaker than in man. Though the foot of man is furnished with many muscles, like the hand, yet not one of the toes is provided with an "opponens" or muscle, passing from the bones of the ankle to one or other of the bones of the middle of the foot, which latter are called metatarsals. The same is the case with the apes, except that the Orang-utan has a small "opponens ■ attached to the great toe.

This being premised, the foot of the Frog may well excite surprise as to its rich muscular structure. In addition to very numerous other muscles on both surfaces every one of the toes is provided with a separate opponens muscle, each having a muscle which passes from the bones of the ankle to its middle foot bone or metatarsal.

The question naturally occurs on beholding this prodigality of muscles—What special purpose is served by the Frog's foot? Surely mere jumping and swimming cannot require so elaborate an apparatus.

In fact, however, the Frog docs make use of his feet for a purpose requiring actions no less dexterous and delicate than nest-building.

In 1872 Dr. Gunther observed a Frog busily occupied, and industriously moving its hind legs in a singular manner. On approaching closely he found it had constructed for itself a shelter in the shape of a little bower, constructed of dexterously interwoven blades of grass. The circumstances have been kindly transmitted to the author by the observer, in a private letter, as follows :—

"The 'nest-building' Frog was a large example of Rana temporaria, or esculenta (I forget which), which I had brought into the garden behind my house. It had taken up its abode in grass, near the edge of a tank, from which the turf sloped abruptly to the level of the garden. When I first disturbed the Frog from its lair, I found that it had lain in a kind of nest, which I cannot better describe than by comparing it to the form of a hare, with the grass on the edges so arranged that it formed a sort of roof over it. Sometimes the animal returned to it, sometimes it prepared a new form close to the old one, which remained visible for several days until it was obliterated by the growing grass.

"When in its nest, nothing could be seen of the Frog but the head.

"One day I poked the Fiog out of its 1 lir; af'.er two or three jumps it returned to the old spot, and, squatting down on the grass, by some rapid movements of the hind legs it gathered the grass nearest to it, pressing it to its sides, and bending it over its body so as to be partially hidden.

"In all these operations no material was collected by the animal for its nest, but only the growing grass was either pressed down, or arranged so as to form a complete retreat.

"Unfortunately, the Frog soon disappeared altogether."

It is very probable that other functions, as yet unnoticed, may be performed by these members, since though the observation just above related is the first known observation of the kind, yet the manoeuvre recorded is no doubt a constant habit of the animal.

Doubtless, also, the very singular actions performed by the male Pipa and Obstetricans are performed by the help of the hinder extremities.

At the same time that the Frog shows so startling a resemblance in its leg muscles to higher animals, it shows

[graphic][merged small]

Kici. 65.—Muscles of Ventral Surface of MtHoiraiuhut. On the right side, superficial muscles; on the left side, deeper muscles, the mylohyoidei, pectoralis, and external oblique being removed. Also superficial flexor muscles of right pectoral limb of Menobranchiis. B, biceps; CBl and CB2, coraco-brachiahs ; CHE, cerato-hyoidcus cxternus; EO, external oblique; PL, flexor longus; GH, genio-hyoid; JlfH' and AfH2, mylo-hyoideus ; _ OH, omo-nyoid: P, Pi, and P-, pectoralis; F, rectus; 5", subclavitis; SH, stcrno-hyoid; SL, supinator longus;' T, triceps.

as striking a difference from the leg muscles of animals with which it is nearly allied,—namely, with those of its class-fellows, the Urodela.

In Reptiles we meet with a muscle which takes origin from beneath the joints of the tail, and is inserted with the thigh-bone, and which has no certain representation amongst mammals, and is called ihe/emorocauda/.

In the Urodela we also meet with a femoro caudal, but no such structure exists in the Anoura. This is not so surprising when we recollect the abortive condition of the tail of the Frog. It might, however, have been expected that in the Tadpole, during the co-existence of the tai with the hind legs, and while it thus externally resemble

[merged small][graphic][ocr errors][graphic]

Fie. 68. -Deeper Muscles of Extensor Surface ot Right Leg of Menopomi. B. biceps j.SB, extensor brevis; EH, extensor hallucis: ELD. extensor longus digitorum ; FC, lemoro-caudal: C.lfrfand G.Vi, muscles like the lesser glutei ; GMx and RF, great extensors of the thigh ; /, muscle resembling the iliacus . lie, ilio-caudal; IP, ilio-peroneal; SM and ST, muscles like the semimembranosus andsemi-tcndinosus respectively; TA, tibialis amicus.

the use of the members, as novel and interesting as the one just cited with regard to the nest-building actions of the Frog.

St. George Mivart {To be continued)

THE ACOUSTIC TRANSPARENCY AND
OPACITY OF THE ATMOSPHERE*

II.

T^E have now to consider the complementary side of the phenomena. A stratum of air, 3 miles thick, on a perfectly calm day, has been proved competent to stifle both the cannonade and the horn-sounds emoloyed at the South Foreland; while the observations just recorded, one and all, point to the

mixture of air and aqueous vapour as the cause of this extraordinary Dhenomenon. Such a mixture could fill the atmosphere with an impervious acoustic cloud on a day of perfect optical transparency. But, granting this, it is incredible that so gieat a body of sound could utterly disappear in so short a distance, without rendering any account of itself. Supposing, then, instead of placing ourselves behind the acoustic cloud, we were to place ourselves in front of it, might we not, in accordance with the law of conservation, expect to receive by reflection the sound which had failed to reach us by transmission? The case

[subsumed][graphic]

[A tunnel 2 in, square, 4 ft. S in. long, open at both ends, and having a glass front, runs through the box a b. The space above and below is divided into cells opening into the tunnel by oblong orifices exactly corresponding vertically. Each alternate cell of the upper series—the 1st, 3rd, 5th, &c.—communicates by a tube (Jil) with the upper reservoir (g), its counterpart in the lower series having a free outlet into the air. In like manner the 2nd, 4th, 6th, &c, of the lower series of cells are connected with the lower reservoir (/) ; and each has its direct passage into the air through the cell immediately above it. The gas distriDutors are filled from both ends at the same time; the upper with carbonic acid gas, the lo^er with coal-gas, by branches from their respective supply pipes {/, /;). A well-padded box (/) opening upon the end of the tunnel forms alittle cavern, whence the sound-waves are sent forth by an electric bell. A few feet from the other end of the tunnel, in a direct line, is a sensitive flam; {/:), provided with a funnel as sound collector, and guarded from chance currents by a shade.

The bell was set ringing. The flame, with quick response to each blow of the hammer, emitted a sort of musical roar, so regular were its alternate shortenings and lengthenings as the successive sound-pulses reached it. The gases were then admitted. Twenty-five flat jets of coal gas ascended from the tubes below, and twenty-five cascades of carbonic acid poured down from the tubes above. That which was a homogeneous medium had now fifty limiting surfaces, from each of which a portion of the sound was thrown back. In a few moments these successive reflections became so effective that not a single sound-wave having sufficient power to affect a flame so sensitive as to be knocked down, crushed, as it were, by a chirrup, or jingle, at twenty feet distance, could pierce the clear, optically-transparent, but acoustically-opaque atmosphere in the tunnel. So long as the gases continued to flow, the flame remained perfectly tranquil. When the supply was cut off, the gases rapidly diffused into tbe air. The atmosphere of the tunnel became again homogeneous, and therefore acoustically transparent, and the flime bowed down to each sound-pulse as before. Alternate layers of common air and air saturated with various vapours produce the same effect]

would then be strictly analogous to the reflection of light from an ordinary cloud to an observer placed between it and the sun. My fir.-t c»re, in the early part of the day in question, was to assure myself that our inability to hear the sound did not arise from any derangement of the instruments. At one P.M. I was

* Royal Institution, Friday evening Discourse by Prof. Tyndall, D.C. T,. Ml1 F. R.S. Jan. 16. (Continued from page 253.)

rowed to the shore, and landed at the base 01 the South Foreland cliff. Ths body of air which had already shown such extraordinary power to intercept sound, and which manifested this power still more impressively later in the day, was now in front of us. On it the sonorous wave3 impinged, and from it they were sent back to us with astonishing intensity. The instruments, hidJcn from vi-;\v, were,on the summit of a cliff

« AnteriorContinuar »