himself, but is likewise able to extract good work out of other people-a task often more hard to be accomplished than the former one. The Countries of the World. By Robert Brown, M.A., Ph.D. Vol. iii. (London: Cassell.) THIS Volume is devoted to Central and South America, and appears to us to present a fairly full and trustworthy and certainly interesting account of the countries of this most attractive region. Dr. Brown has evidently taken the trouble to search most of the authorities likely to help him. The illustrations to this volume are unusually good and appropriate. 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.] A Carnivorous Goose I INCLOSE to you an account of a Golden Eagle, which I have reason to know to be authentic. The possibility of a bird so purely graminivorous as a goose being taught to eat flesh, and acquiring the power of digesting it, is extremely curious. It is well known, however, that cows are largely fed on fish offal in Scandinavia, and I have heard of a Highland cow devouring a salmon which an unwary angler had hid among fern on the banks of a river in Sutherland. ARGYLL Isola Bella, Cannes, April 7 "March, 1879.-There is in the possession of W. Pike, Esq., at Glendarary, in the Island of Achil, Co. Mayo, a Golden Eagle, now about twenty-five years old, which was taken from the nest and brought up in confinement. This eagle, in the spring of 1877 laid three eggs, which Mr. Pike took away, replacing them with two goose-eggs, upon which the eagle sat, and in due time hatched two goslings. One of these died, and was torn up by the eagle to feed the survivor, who, to the great tribulation of its foster-parent, refused to touch it, together with the other flesh with which the eagle tried to feed it, Mr. Pike providing it with proper food. The eagle, however, in course of time, taught the goose to eat flesh, and (the goose having free exit and ingress to the eagle's cage) always calls it by a sharp bark whenever flesh is given to it, when the goose hastens to the cage and greedily swallows all the flesh, &c., which the eagle, tearing its prey to pieces, gives it. 'I saw them in May, 1878, when, the goose being a year old, had made a nest in the eagle's cage, and laid eleven eggs, and the two birds were sitting side by side on the nest. I hear from Mr Pike that he did not allow them to hatch out, fearing that it might interfere with their attachment to one another. "The eagle is very tame and fond of Mr. Pike; he goes into the cage, and it allows him to handle it as he likes, but will not allow any one else near it. It never attempts to get out of the hole made for the goose to go in and out.' Sense of Force and Sense of Temperature 66 THE sense of force, or of resistance to pressure, and the sense of temperature, have been very commonly confounded under one name, sense of touch." Indeed, I think they are still imperfectly distinguished in many modern works dealing with the sub. ject of sensation. Nevertheless, there can be no doubt as to these two being sensations altogether distinct. It is even quite probable that they are observed and transmitted by distinct nerve-systems. An important and interesting question arises as to the kind of information given to us by these two senses; viz., how far it is merely relative, and how far these senses may, by cultivation, be made to give us absolute information. So far as the sense of force is concerned, it is with most persons chiefly relative. Every one is prepared to say, but generally very roughly, that of two bodies, A and B, A is heavier than B. To test their relative weights we lift first the one and then the other, and decide between them. Sometimes we may go a little farther towards making an absolute estimate by means of the sense of force. I can tell, for example, that a weight is greater than 20 lbs. and less than 30 lbs. by trying to hold it out at arm's length; and most likely with a little practice I could learn to estimate weights to within closer limits than 5 lbs. on each side of 25 lbs. But such testing as this is all that is done in ordinary cases. There is, however, a very remarkable case in which the sense of force is made absolute to a high degree by practice. It is the case of letter-sorters in the Post Office, who learn to distinguish letters that are over a particular weight with accuracy that is perfectly marvellous. It would be very interesting to try a series of experiments with letters of different weight, some slightly under weight for a particular postage, and some slightly overweighted, and to observe the errors or rather the limits of uncertainty. The sense of temperature may also be rendered absolute to a certain extent. Several instances might be mentioned, some of which depend, as in the case of testing force by lifting the greatest possible weight in a particular way, on the limit of endurance. One remarkable case of an absolute determination of temperature by the senses is that of the plumber and tinsmith who are in the habit of holding up the soldering bolt to the face, and judging by feeling whether it is at the proper temperature for a particular piece of work in hand. Probably there are other cases in the arts in which the sense of temperature is cultivated to a high degree. It is in the hope of getting information on this subject through your readers that I address this note to you. J. T. B. April 7 Did Flowers Exist During the Carboniferous Epoch? MR. A. R. WALLACE, in his review of Mr. Allen's, "The posing the fossil insect from the Belgian coal-fields, named BreyeColour Sense" (NATURE, vol. xix. p. 501), has been misled in supria borinensis may be a moth. It was originally described as the hind wing of an orthopterous insect, under the name of Pachytylopsis borinensis (Comptes Rendus, Soc. Ent. Belg. xviii. p. xli). Subsequently it was transferred to the lepidoptera on bad advice, and re-named Breyeria borinensis (same Comptes Rendus, p. lx.). fossil at Brussels in 1877, and have no doubt it belongs to the Its original location was nearer the truth. I examined the pseudo-neuroptera, family Ephemerida (vide my note to this effect in the same Comptes Rendus for 1877, xx. p. xxxvi.). The very dense transverse reticulation did not receive sufficient importThus we remain without any zoological evidence that would tend ance when M. de Borre was induced to refer it to the lepidoptera. to prove the existence of flowering plants in the carboniferous age. R. MCLACHLAN Lewisham, April 4 Water-level Indicators I OBSERVE in NATURE (vol. xix. p. 518) a description of what is stated to be a new form of water-level indicator which has lately been erected by the India-rubber, Gutta-percha, and Telegraph Works Company, at the Leamington New Waterworks. So far as mere form goes, it possibly may be considered new, but hardly so in any other sense, as a water-level indicator, fulfilling the purposes you mention, on a very extended scale, has been in action at the Nottingham Waterworks for many months past. It is not only capable of being made to give smaller indications than one foot, but is actually doing so. This apparatus was designed and constructed in the electrical department of the General Post Office, and has given great satisfaction. I may mention that it was under the consideration of Mr. Preece so far back as the latter end of 1877, and but for his determination to have an instrument perfect in every respect before he turned it out, it might have been at work early in 1878. Nottingham, April 8 Eastern Yucatan H. ROFE Is there any information to be had about Eastern Yucatan? In 1847 the Maya Indians there rose against Mexico and have become independent. The animosity between them and the Mexicans is so great that there is scarcely any possibility of penetrating to the Independent Indians of Eastern Yucatan from the western part of the peninsula, which remains Mexican. But should this not be possible from Belize (British Honduras)? I have heard that the coloured people of the colony trade with the Mayas. Would it be possible then to obtain some information in this way? As to the interest of a visit to the Maya country by an educated traveller it would bear especially (1) on the condition of the people since they are free from their white masters. How does it compare with the condition of the Mayas of Western Yucatan, who live in a de facto serfdom to the large landowners? (2) The antiquities, of which we have a description by Stephens, but certainly would know more. Very likely the Mayas will allow a white man who is not a Spanish-American to travel in their country; they have no special reason to hate anybody except the latter. A. WOEIKOF Jurschtatskaya, 9, St. Petersburg, March 25 Deltaic Growth IN reference to the question as to the amount of sediment brought down by Delta Rivers, I had occasion in 1877 to ascertain the amount of sediment carried by the waters of the River Plate, and found it to amount to thend part by weight. Mr. J. F. Bateman, the well-known hydraulic engineer, in his report on the proposed harbour of Buenos Ayres, fixes the minimum flow of the River Plate at 670,000 cubic feet per second. Assuming its mean volume at 700,000 cubic feet per second (a quantity very much under the mark), it would appear that this river carries seaward some 224,000 tons of sediment every twenty-four hours-or say, in round numbers, 82,000,000 tons every year. Some portion of this sediment is deposited in the 100 miles of river that intervene between Buenos Ayres and the sea, forming the great banks that render the navigation of the River Plate so troublesome, but a large portion is carried out to sea and deposited beyond the mouth. I have been informed by captains of steamers trading with Buenos Ayres that the soundings shown on the chart of the coast of Uruguay vary considerably, in many places, from the actual ones now existing, and I have little doubt that a correct resurvey of this coast would show changes as marked as those discovered by Mr. Doyle near Rangoon. The subject is one of great importance, as the coast of Uruguay is a difficult and dangerous one to make, and from the low character of the coast, the frequency of fogs, and the great uncertainty of the currents, captains have frequently to depend a great deal on the lead to ascertain their position when making this land. During the last few years several fine steamersFrench, German, and English-have been lost on this coast near the Castillos, when making the land. GEORGE HIGGIN 3, Great George Street, Westminster, S.W., April 10 Temperature Equilibrium in the Universe in Relation to the Kinetic Theory My attention has been called to an ambiguous phrase in my recent paper on the above subject (NATURE, vol. xix. p. 460) which it is necessary to rectify. On page 461 is the sentence "Let us suppose now the excessive temperature to fall, or, in other words, the total energy to diminish." This is meant as a supposition, not as a possible case. The imaginary rise and fall of temperature in the universe are given merely for the sake of aiding the conceptions of the actual facts, by affording imaginary cases to show what the effects would be if such cases were possible. S. TOLVER PRESTON London, April 15 Transportation of Seeds THE penetration of seeds of the so-called "flechilla" grasses into the flesh of Australian sheep is too well known to squatters. On some "runs "" these grasses are so abundant that the annual loss of stock is a very serious matter. The ripe seed falls upon the wool, and, owing to the re-curved barbules with which it is armed, easily penetrates to the skin, when, its point being as sharp as a needle, every movement of the animal tends to drive "On the Possibility of Explaining the Continuance of Life in the Universe Consistent with the Tendency to Temperature-Equilibrium." it into the flesh. I have found the internal organs so crowded with seeds that they felt like a bag of needles if squeezed in the hand. ARTHUR NICOLS Earthquakes A SHOCK of earthquake was felt in this neighbourhood on the evening of Tuesday, April 8, at 8.35 (about). We were sitting in the drawing-room of this house, when we heard a sound like It in the rumbling of a heavy waggon, or distant thunder. creased in loudness till the room slightly vibrated and the window rattled, as it seemed to. pass the house. From the peculiar nature of the sound, and the fact that we are some 50 feet above the road, and 80 or 100 yards from it, I felt certain the disturbance was due to an earthquake and not a passing waggon, but walked to the window to listen, when I heard the sound dying away in the distance. It seemed to come from the south-east, and travel towards the north-west, and to be audible, from first to last, for some seconds, perhaps five or six, because we spoke one to another during the time. I find that the shock was noticed by other people in the neighbourhood, and that in a cottage near Bettws Gormon, a mile or so from here, two glass bottles were thrown down from a high shelf and broken. T. G. BONNEY Bron Celyn, near Bettws y Coed, North Wales, April 10 We were visited by an earthquake of some violence this morning at 2 A.M. (Cadiz mean time). The shock was preceded by a profound subterraneous noise like that of a distant carriage, and it extended to Port St. Mary and Port Royal (six miles). The earthquake travelled from south to north approximately; some clocks stopped. AUGUSTO T. ARCIMIS Cadiz, April 3 OUR ASTRONOMICAL COLUMN BESSEL'S NEBULA IN PERSEUS.--On November 8, 1832, in zone 527, Bessel observed an object, which he recorded as a nebula, distant about one degree from 20 Persei. It is No. 1,063 of Weisse's second Catalogue, where, though called a nebula, it has 9m. attached. D'Arrest, in his "Resultate aus Beobachtungen der Nebelflecken und Sternhaufen," has two observations, in January, 1856, to the first of which he attaches a note that no nebulosity was visible in Bessel's position, and that possibly a comet was observed; the second observation records a star 9'10m., without trace of nebulosity or diameter, the place of which was found to be within a few seconds of arc from Bessel's position, preceded 24225. by a star 9m., 76" to the north. In "Siderum Nebulosorum," &c., D'Arrest remarks: "Star 9m. quæ Besselio quondam nebulosa apparuit... Argelandro in Perlustratione ceu fixa 9°3 magn. apparuit; nobis sæpius inspicientibus nunquam nebulosa visa." This refers to the star in the "Durchmusterung," at 2h. 43m. 56'5s. + 36° 54'2; Argelander has another star of the same magnitude, 9'3, 10' south. Are we to infer that Bessel's star was surrounded in 1832 by nebulosity so conspicuous that it was caught at once in his zone observations, which had wholly disappeared in 1856, or, as appears the more probable conclusion, that at the time of his meridian observation a comet happened to be centrally over the star? In this case the observation gives its place for 1832 November 8 at Ioh. 10m. 25s. G.M.T.; the catalogued position for 18250 is in R.A. 2h. 42m. 5'56s., Decl. +36° 46′ 46′′*7. This observation of Bessel's might at first sight appear of some interest, considering that the comet of the November meteors (1866 I.) must have been near perihelion about November 1832, but upon further examination it will be found that with the elements of 1866 it is not possible to bring the comet near the observed position of the "nebula," upon any assumption as to the time of its arrival in perihelion. BRORSEN'S COMET.-Comparing the second of the two observations on April 4, in Major Tupman's letter pub = lished in NATURE, vol. xix. p. 527, with Dr. Schulze's Mr. Tebbutt, of Windsor, N.S.W., writes that, aided by Dr. Schulze's ephemeris, he found the comet on February 22, and observed it again in the fading twilight on the following evening. It could hardly be seen with a telescope of less than four inches aperture. It had the appearance of an elliptic nebulosity, the major axis of the ellipse extending in the direction of the parallel of declination. NEW MINOR PLANETS.-Prof. Peters, of Clinton, New York, notifies his discovery of No. 194, on March 22, in R.A. 12h. 11m., Decl. + 9° 31', magnitude 10'5. No. 192 was found by M. Palisa at Pola on February 17, and No. 193 by M. Coggia, at Marseilles, on March 1. GEOGRAPHICAL NOTES AT the meeting, March 22, of the Russian Geographical Society, Col. Petroussevitch read a very interesting paper on his exploration of the Amu-daria, from Chardjui, in Bokhara, to the delta of the river, and on its former beds. M. Petroussevitch has arrived at the conclusion, based on a thorough levelling of the country, that the turning of the waters of the Amu-daria into the Sara-kamysh depression through one of the former beds, would not meet with great difficulties. This depression being, however, very wide and deep, the waters of the Amu River once arrived there, would form a great lake, and it would be difficult to direct them further to the Caspian. For this last reason it would be better to open a way for the waters of the Amu along one of its former beds which run southeast from the lake Sara-kamysh. All explorations make it very probable that in this way the Amu-daria could easily reach the Caspian. The Russian Trade Society sends, next summer, an expedition for the study of the lower parts of the Amu-daria, of the best direction for a railway to Central Asia, and of the possibility of a canal between the Amu and the Caspian. Several officers of the Russian general staff, with geodesists, a geologist, a botanist, an archæologist, and an artist will be members of this expedition. They will start from the Ural River, passing through Kara-tugay, Tashkent, and Samarkand; further they will go down the Amu to the Uzboi. UNDER the title of " L'Afrique Centrale en 1522," M. A. J. Wauters, Assistant-Secretary of the Belgian Geographical Society, has drawn up an interesting memoir, in which he has gone with much care into the doctrine of Portuguese geographers respecting the discovery of Central Africa in the sixteenth century. M. Wauters was induced to study the subject by the recent discussions in regard to the geographical data furnished by the great globe in the Lyons Library, and if anything were required to dispose of its claims to originality, this memoir does it most effectually. He traces back the idea of a great central lake, under the name of Saphat or Sachaf, to the days of Martin Hylacomilus and Gerhard Mercator, so that the data on which it was based must have been known previous to the year 1522. M. Wauters's memoir appears in the current number of the Bulletin of the Belgian Geographical Society, and is illustrated by a facsimile map. A LISBON paper gives the text of a letter which Major Serpa Pinto addressed to Sir Theophilus Shepstone from Shoshong, Bamangwato country, on January 2, and which adds some information to that already made public respecting his adventurous journey. He states that he went beyond the Zambesi and purposed proceeding to the east coast through the country of the Choculumbes, when successive obstacles obstructed his passage. Having lost all his resources and being abandoned by his carriers, he found himself in the greatest difficulties, when fortunately he heard of a missionary who had arrived at the Upper Zambesi, and he resolved upon finding him. After a journey of 200 miles he found the missionary, M. F. Coillard, a Frenchman of the Evangelical Mission of His strength being exhausted, Major Pinto was taken Sesuto, Basuto-land, director of the station of Lesibo. seriously ill, but on his recovery succeeded in reaching Shoshong with M. Coillard and accompanied by eight of his followers, the only ones who continued faithful. THE Danish Government has appointed Lieut. Jensen to explore all the fjords in Greenland from Holsteinborg to the coast facing Disco. The explorations will bear on the moving ice-fields which send so many icebergs into the Polar Ocean. MR. IM THURN paid a second visit to the Kaieteur Falls, on the Potaro River, British Guiana, in February and March last, when the river was in full flood. Referring to our remarks on his previous visit, he states that he by no means intended to depreciate the grandeur of the fall. At his last visit he found it " so infinitely more grand, so infinitely more beautiful, that it is painfully hopeless to try to express in words anything of its beauty and grandeur." Mr. im Thurn's brief account contains several interesting notes on the botany and zoology of the region traversed. THE WOLF FISH F late the wolf fish (Anarrhichas lupus) has been somewhat plentiful in the Frith of Forth. A specimen which lived in the Edinburgh Aquarium for a little over a week, came into my possession a few days ago, and I have thought that an account of the dental armature of this curious fish may prove interesting to readers of NATURE. The wolf fish is a near relative of the Blennies. In this fish we see the same elongated dorsal fin, and the same anal fin as in the Blennies; but the dental arrangements of the wolf fish are of a much more specific and unusual kind than are seen in the former group. The specimen dissected measured twenty-five inches from the top of the nose to the extremity of the caudal fin. It was therefore by no means a large specimen, since from six to seven feet is not an unusual length for the sea wolf to attain. Its dark grey body was faintly banded with brown, but the head was beautifully and distinctly marbled with black on a grey ground. The aspect of the mouth, provided with its well marked teeth, partakes somewhat of a feline sea cat," often look, and has suggested the name applied to it on these northern shores, where the fish is frequently eaten, it somewhat resembling the cod in taste. The appearance of the mouth is highly characteristic. In front of both jaws is found an array of sharp incisor teeth. The upper jaw bears five of these pointed teeth, the two lateral teeth being large, and the central three teeth small. The lower jaw possesses six teeth of similar pattern, the two central teeth being larger than the four lateral ones; and when the jaws are closed the lower teeth interlock in an exact manner with the upper. The hold or grip of a wolf fish must therefore be of a tenacious kind. Behind these incisor teeth, both above and below, are seen a few small teeth, destined by the ordinary laws of dental succession in the fish-group to replace the incisors in case of injury or loss. These front teeth are firmly anchylosed to the bones on which they are borne. More interesting are the palatal teeth, and the corresponding teeth of the lower jaw. To these latter, the name of "molars" or "grinders" is frequently applied. Close to the front of the upper jaw we find a series of three tooth-masses, one central and two lateral, arranged in diverging fashion. The central and largest mass resembles the tuberculate molar of a bear in form, and is composed of four firmly united segments, each segment in turn consisting of two pieces. The lateral teeth of the palate, similarly consist of a double series of firmly united segments, but in each of these lateral pieces the outer row of pieces is composed of sharp-pointed segments, resembling miniature incisors. The accompanying diagram will afford an idea of these curious palatal arrangements: A is the central piece; B and C are the lateral pieces, the outer teeth of which (pp) consist of pointed and incisor-like pieces. It follows from this description that the sea wolf possesses in its mouth an apparatus not merely adapted for tearing its food but for exercising a triturating and bruising action as well. perfection in such widely-removed fishes as the Elasmobranchiate Skates, Rays, and Cestracion. The stomach of the specimen I dissected was greatly distended, and contained fully four ounces of digestive débris, consisting chiefly of disintegrated Ophiuroids, spider-crabs, broken shells, shrimps and prawns, along with sand and small gravel. The pyloric aperture was firmly contracted and the collection of matter in the stomach clearly pointed to some obstruction of the digestive canal as the cause of death. It was also instructive to find that close to the vent the rectum was largely distended with broken pieces of shells and fine gravel. These matters, along with those in the stomach, had evidently been intussuscepted before the arrival of the fish in the aquarium and probably caused death by the irritation consequent on their non-removal by digestion. ANDREW WILSON No less characteristic are the dental arrangements of the lower jaw. In the front of this jaw are four incisor teeth, each fully three-quarters of an inch in length; whilst two smaller incisors exist as already mentioned, one at each side of the larger series. Behind these incisors are the rudiments of succeeding teeth, and these rudimentary teeth gradually merge into the main dental arrangement of the lower jaw, which consists of a prominent row of blunt teeth anchylosed to form a common mass, and partially forming a double row on each side of the jaw. Section of the jaw shows that the teeth are imbedded in a common groove, and that complete and thorough ossification of the various dental pieces renders the whole apparatus compact and solid. The arrangement seen in the mouth of the wolf fish suggests the idea of the high specialisation of this type of fish, as indicated by the development of the dental apparatus. In none of the near neighbours of this fish have we at all a near approach to the perfection of teeth thus exhibited; and in respect of its complexity and differentiation of type, we may well be inclined to lend some countenance to the idea of the independent origin in widely removed fishes of structures seen in still greater IT THE ETNA OBSERVATORY T will be within the recollection of some of our readers that in September, 1876, Prof. Tacchini, of Palermo, communicated to the Accademia Gioenia of Catania a letter, "Sulla Convenienza ed utilita di erigere sull' Etna una Stazione astronomico-meteorologica" (vide NATURE, vol. xv. p. 262). This letter was published in the Atti of the Academy, and afterwards appeared in the form of a quarto pamphlet with ground-plan and elevation of the proposed building. The project was at once taken into consideration both by the Italian Government and by the Municipality of Catania; plans were prepared, money was voted, and it was confidently believed that the observatory would be commenced in July, 1878. Owing, however, to certain delays, this was found to be imprac ticable, and the commencement was postponed till June, 1879. There is every reason to believe that the building will be erected and the instruments in working order by the end of this year. The cost will be borne by the Government, the Municipality of Catania, and the Province of Catania. Merz, of Munich, has offered to construct a 12-inch lens for the great refractor, at the price of a 10-inch lens, and the enterprise has received encouragement and support from various sources both at home and abroad. The observatory will be erected at the Casa degl' Inglesi, 9,652 feet above the level of the sea. At the present time the Casa is an oblong building constructed of blocks of lava, and containing three rooms (vide the accompanying plan). It was built by the English when they occupied Sicily in 1811, and has since been used by those who ascend the mountain as sleeping quarters. A few years ago it had fallen into decay owing to the accumulation of snow in winter and to other causes, but it was put into complete repair in 1862 on the occasion of the visit of the present King of Italy. The observatory will be the property of the University of Catania, and will indeed be a kind of offshoot of the Bellini Observatory of Catania. It is to be devoted not only to astronomical and spectroscopic observations, but it will also be furnished with a complete set of meteorological and seismological instruments. Between the Etna Observatory and Catania three or four meteorological stations will be established at different elevations, as at Nicolosi, and the Casa del Bosco, and observations will be made at the same hour daily at each of these stations, at Catania, and at the Etna Observatory. The Merz lens of 12 inches diameter, has a focal distance of 5 metres. The telescope and clock-work movement are in course of construction by Signor Carignata, the mechanician of the Padua Observatory, who constructed the instruments which were employed by the Italian astronomers who went to India to observe the transit of Venus in 1874. The observatory will only be inhabited during the months of June, July, August, and September, and the large lens will then be transported to Catania, and fitted to a duplicate mounting in the Bellini Observatory. But a number of self-recording instruments will remain in the observatory, and thus results will be registered during the winter months. Prof. Tacchini, to whom the whole undertaking_owes its existence, specially desires that it should be an International Observatory. With this object in view, the large telescope will be fitted with a second tube, the length and aperture of which can be altered at will, so that astronomers from any part of the world can bring with them their objectives and eye-pieces, and can fit them to the telescope of the observatory. Special arrangements will be made for photographing the sun and moon, and for spectroscopic observations. The observatory will contain the large telescope covered by the usual dome in the centre; on each side there will be rooms for the other instruments, and below, sleeping quarters, a dining-room, and kitchen for the use of travellers. The following plan, for which, together with many of the above facts, we are indebted to Prof. Tacchini, will show the general arrangement of the observatory. In his report on the subject Prof. Tacchini commences by pointing out that since the year 1868 the study of the physical constitution of the sun has made very rapid progress. In these studies the spectroscope has played a very important part. But the spectroscopic observations are often hindered, and their exactitude is disturbed by atmospheric causes, and these disturbances are mainly due to the lower layers of the atmosphere. Hence an observatory at a considerable elevation would greatly facilitate such observations. The isolated Mount Etna affords an admirable locality for such an observatory, The blueness of the sky is intense, the stars shine with an extraordinary brightness, Venus casts shadows, spectroscopic lines which cannot be seen at the Palermo Observatory are perfectly distinct when viewed from an elevation of 10,000 feet. Ora il mio desiderio," says Tacchini, “sarebbe quello di andare sull' Etna per verificare la tanto decantata purezza del cielo e il suo colore speciale, osservare l'aureola del sole, studiarne lo spettro se sarà possibile e fare anche qualche tentativo di fotografia. He then mentions some of the observations made by Young with a 9-inch refractor at an elevation of 2,800 metres, and describes his own observations made on Etna with a Dollond refractor of 99 mm. aperture, a, b, c, the three rooms of the already existing Casa Inglesi; d, circular chamber, 8 metres in diameter, with a massive pillar in the centre, upon which the great refractor will be placed; e, a room for guides who accompany those who ascend the mountain; g, kitchen and offices; stable for mules;, staircase. On the upper floor, a, b, c, will be bed-rooms; e, g, i, instrument-rooms; and d, the circular chamber for the refractor, extending through both floors, and surmounted by a movable dome of iron. and a spectroscope of great dispersive power constructed by Tauber. La cromosfera era magnifica e dettagliata abbastanza tenendo conto della piccolezza del magnesio e dello 1474, ciò che non vidi a Palermo collo stesso cannocchiale.' Then having made the suggestions which are in part carried out, and which have entirely been adopted, he concludes by a fervid peroration which we heartily endorse :-"Io ritornerò dunque all' Etna, lo spero, e in migliore stagione, e sin d'ora mi figuro coll' immaginazione, la vista della nuova specola, che mi ricorderà l'epoca fortunata e la circonstanza solenne, che qui mi tiene ora unito a voi, e il nome del grande Bellini, che prima ancora di dare alle scene il suo capo lavoro, la Norma, volle in omaggio alla scienza degli astri, suonare all' osservatorio di Palermo la celeste melodia della preghiera alla casta Diva." While we feel perfectly convinced that important results will accrue to more than one science from the establishment of the new observatory, we must not shut our eyes to the fact that many difficulties will have to be encountered. The observatory on Vesuvius stands upon a projecting spur of rock, and lava-streams of any ordi nary magnitude breaking out on this side of the cone would divide, and leave the observatory as on a rocky island. But the Etna Observatory will stand near the upper termination of the Piano del Lago, the plain out of which the great cone of Etna rises. A great eruption, leading to the breaking down of the cone and flow of lava in this direction, could not fail to overwhelm the Observatory. Fortunately the lava usually finds vent by a bocca del fuoco on the sides of the mountain below the great cone. The building must be of very great strength; it will be subject to violent shocks of earthquake, to fierce storms of wind, and to the accumulation of great masses of snow upon its dome and roof. Those who have read the history of the mountain know with what tremendous power it scatters its terrors abroad; how hours of loud bellowings and detonations are followed by days of violent earthquake, and weeks during which many square miles of country are inundated by millions of cubic yards of molten lava. That the new Observatory may flourish, unassailed by the fearful forces of the imprisoned Cyclops, will be the wish of all our readers. G. F. RODWELL |