also no opportunity for the filtering through of small portions of dissimilar air, and, if portions do descend into the lower levels, they are broken up, diffused, and dispersed. Still, in the colder half of the year, if the lower wind blows from between east and north, and does not extend to a great height, a strong mist may be produced by its being mixed with detached portions of the westerly upper current, which take a long time to be thoroughly incorporated and dissolved, and contain more vapour than they can hold invisible in contact with the cold surface-breeze. Thus the prevalence of much haze with a north-easterly gale indicates an equatorial upper current, and the polar wind is apt to be replaced by it before long. With regard to showery weather, it may almost be said to be the opposite of hazy weather, and for -First, as we have seen above, the following reasons:showers are produced by the upward projection of lower air, containing a good deal of vapour, into upper cold air of the same kind. Then, they are often the expression of a state of the atmosphere when the interchange between the upper and lower strata proceeds by large ascending columns and large down-rushes, instead of by small convection currents, and ascending and descending filaments The clearness of the air with a over a very large area. showery north-east wind is quite surprising, for it is sufficient to banish to a great extent even London smoke., Here, again, the north-east wind prevails to a great height, and the air is homogeneous and rather dry. When a shower or even a cumulus cloud passes over a large town, the smoke is seen to be drawn up in a moving Probably the chief coluain to the height of the cloud. cause of the clearness of a showery north-east wind is the prevalence, as in other cases, of the same wind in the upper regions, so that there is no admixture of strange threads in its composition, no strands of extra-humid particles to be rendered visible by incipient condensation. (3) Winds between south-west and north. These are, on the whole, clear for a similar reason, for it has been shown that the upper currents in Great Britain usually move from between south-west and north-west. If, as occasionally happens, an east wind blows overhead, they are very far from transparent. (4) Fine settled summer weather, with westerly or southerly winds, is clear not only for the reason above stated, but on account of the general moderate dryness of the atmosphere. In such weather, barometric pressure is frequently highest over Spain or France, and our upper currents are accordingly from north-west, becoming warmer as they advance southwards and increasing in There would be no condensation capacity for moisture. if portions of these currents were to descend into the lower air. is, Settled easterly or northerly winds, with either clear sky or high clouds moving from those directions. Haze does not form where the wind is steady, the air dry and homogeneous up to a great height, and equilibrium stable, for there is nothing to lead to condensation except at the particular level of saturation where clouds are manifested. (6) Easterly or northerly winds with a high continuous cloud canopy moving in the same direction, small range of temperature, and steady conditions; or, with detached cumulus in the daytime, and clear nights. remarks apply here as to the last. The same It (7) North-west wind, reaching that point from west or south, is particularly clear. Great transparency in this case is not a sign of rain, but rather of fair weather. is probably due to its agreement in general direction with upper currents, the increasing dryness as it reaches warmer latitudes, and to the uniformity and equilibrium attained by passing over the ocean. F. A. R. RUSSELL. 65 THE PULSION MECHANICAL TELEPHONE. A NEW mechanical telephone of extraordinary power has recently been exciting considerable attention in London and some other cities and towns in this country. It is of American origin, like so many other modern improvements of exceptional character, being the invention of one Lemuel Mellett, I believe of Boston, U.S. There have been many previous mechanical telephones, as your readers are aware, some of which have obtained much publicity for a short time, and then have been heard of but little more; but having had opportunities of experimenting frequently with the new instrument, and observing its vocal power, so to speak, under very various circumstances, I cannot doubt that it has a great future before it. It may be clearly stated at once that the pulsion instrument is absolutely independent of all electrical aids or appliances, and therefore needs neither battery power to It consists solely of two cheap and bring it into play, nor insulation of any of its parts to keep them effective. simple instruments connected by an ordinary non-insulated wire of copper, or, better still, of a double steel wire, the two parts being slightly intertwisted, say with about a single turn in a couple of feet. The wire (or wires) is simply looped to the instrument at either end, the connection being made in a few seconds. The instrument consists of a disk in combination with a series of small spiral springs inclosed in a case of some three or four inches in diameter. These springs, arranged in a manner that has been determined by experiment, and so as to produce harmonized vibrations, appear to possess the power of magnifying or accumulating upon the wire the vibrations which the voice sets up in the disk, and the wire seems to possess-undoubtedly does possess-the power of transmitting to great distances, and giving out upon a second pulsion instrument, the sounds of the voice. The ability of this simple system of springs, disks, and wires to convey conversational and other sounds to considerable distances with great clearness and distinctness, reproducing the very tones of the voice and the qualities of musical sounds with but little reduction or modification, is most surprising, and to none more so than to the many men of science who have been recently experimenting with it. The writer of this notice cannot, perhaps, do better than state his own experiences with this system. After examining and experimenting over several short lengths of wire, some of them exceeding a mile and a half, he last week went to the Finchley Road Station of the Midland Railway, from a point near to which a line had been conveyed to near the Welsh Harp Station, a distance of three miles by the line of railway, and of more by the track of the wire, which for the larger part was carried Conversation through this length of line, by the telegraph-posts, to which it was attached by very simple means. of over three miles, was exceedingly easy; indeed, so powerfully was the voice transmitted, that an ordinary hat sufficed for all the purposes of the second instrument, without going near to which conversation was carried on repeatedly by means of the hats of three gentlemen who were present, the tops of which were merely placed against the telephone wire. I then went into the garden of the "Welsh Harp," where a short length of wire had been led between two points, the wire on its way from one point to the other being twice tightly twisted, at an interval of some yards, round small branches of trees, of about 1 inch in diameter, being wound round and round the branch three times in each case. Strange to say, this tight twisting of the wires round the branches in no way interfered with the transmission of the voice from end to end of the wire. A third and last experiment was made with a wire laid obliquely across the Welsh Harp lake, and allowed to sink to, and rest upon, the lake bottom. The length of the line was roughly estimated at about one-third of a mile, and from end to end (excepting a few yards at each end where the wire was led from the water's edge to the telephone box) the wire was completely immersed, and without any other support than the bottom of the lake offered it. Yet, notwithstanding this immersion of the whole wire, conversation was carried on through it by means of the pulsion instruments without the least difficulty. In fact, the voice came through the immersed wire, and the longest wire (of over three miles) previously mentioned, with greater purity and mellowness than through shorter lengths. I must leave to others to explain, and if necessary to discover, the scientific grounds of the success of this extraordinary little instrument. Looking, however, at its practical capabilities as exemplified above, it is not surprising that Post Office, police, railway, and other commercial people, are already overwhelming with applications those who are arranging to supply the new telephone, which from its extreme simplicity is manifestly a cheap one. NOTES. No fewer than 1810 patients bitten by dogs were treated at the Pasteur Institute in the year ending October 31. There were thirteen deaths. THE Daily Graphic, the first number of which will appear on January 4, will be interesting from a scientific as well as from a popular point of view. Twenty years ago, when the Graphic was started, so bold an enterprise would have been impossible. At that time the pictures in illustrated journals were produced only by the old method of wood-engraving, which could not, of course, supply all the needs of a daily illustrated paper. By means of various scientific processes, drawings can now be so rapidly and effectively reproduced, that the issue even of a daily illustrated journal may be safely undertaken. The new paper is likely to afford a very striking instance of the influence of these processes on art and journalism. THE Government of New South Wales has adopted an entirely new scheme of technical education. The present Board of Technical Education is to be abolished, and technical schools will be placed under the direct control of the Education Department. A sum of £50,000 is to be expended in the erection and equipment of a new Technical College and Museum in Sydney, while branch technical schools will be established throughout the country districts. It is estimated that £50,000 will be required annually to carry out the new arrangements. MR. E. W. COLLIN has been deputed by the Government of Bengal to make inquiries as to the present condition of technical education in Bengal, and to find out what steps should be taken by the Government towards its advancement in that Presidency. The Civil Engineering College at Seebpore, an institution for the training of overseers and civil engineers, is supported by the Bengal Government, but it does not appear that there are any means at present in Bengal for the technical training of artisans. Mr. Collin has addressed a circular to various public bodies asking for information, and he will submit a report on the question about the end of the year. MR. G. BERTIN is to deliver, at the British Museum, a series of four lectures on the religion of Babylonia. The first lecture will be given on November 26, and the others on the three following Tuesdays, at 2.30 p.m. MR. G. B. SCOTT, of the Indian Survey Department, w has lately been employed on a survey of the Wards Estate r Bengal, has been placed in charge of the new Cadastral Surve of Upper Burmah. THE next conversazione of the Royal Microscopical Soney will be held on Wednesday, the 27th instant, at 8 o'clock. MR. THOMAS CHILD, who has just returned from Pekin, ha sent us very beautiful photographs of the two interesting c astronomical instruments at the Pekin Observatory. The.. instruments are the most ancient of the kind in the world having been made by order of the Emperor Kublai Khan in the year 1279. They are exquisite pieces of bronze work, and ar in splendid condition, although they have been exposed to 12weather for more than 600 years. They were formerly up the terrace, but were removed down to their present position make way for the eight instruments that were made by the Jesuit Father Verbiest in 1670, during the reign of the Empere K'ang Hsi, of the present dynasty. THE metric system of weights and measures having bee adopted in the Photographic Office of the Indian Survey, a series of tables for the conversion of these measures to Brits, and vice versa, has been prepared by Colonels Thuillier 20: Waterhouse, Surveyor-General and Assistant-Surveyor-Genera of India. The scope of the tables, however, has been extended so as to meet, as far as possible, the ordinary requirements f general and scientific reference. The multiples and fractions the British and metric units have each their equivalent expressed in the other, so that the number requiring to be converted may be multiplied directly by the decimal fraction representing the equivalent value of one unit of the required denomination. The relative equivalents are given for the conversion of measures ut length, weight, and capacity, cubic and square measures, and also of British-Indian and metric weights. There are also a few miscellaneous tables that may be found generally useful. It is well known that whales can remain a long time unde water, but exact data as to the time have been rather lacking. In his northern travels, Dr. Kuckenthal, of Jena, recentiv observed that a harpooned white whale continued under water 45 minutes. THE elephant skeleton set up in the front hall of the Madras Museum is 10 feet 6 inches high, and it has been stated that this is the skeleton of the largest elephant ever killed in India. Mr. Edgar Thurston, Superintendent of the Museum, in his lates Report, says that this is a mistake. Mr. Sanderson gave 10 feet 7 inches as the largest elephant he had met, and there is a st larger one in the Indian Museum, Calcutta. SOME fragments of a gigantic elephant's tusk (we learn from the Rivista Sci. Ind.) were lately obtained by Signor Terrenzi, the tusk having been found in the yellow Pliocene marine sands of Camartina, Narni. It must have been about 10 teer long. One piece (which seems to have been near the base measured about 2 feet round at the thickest. The tusk had been broken up by the peasants, and distributed as an intallitle remedy for tooth-ache and for belly pains in cattle! It probably belonged either to E. meridionalis, Nesti, or to E. antiquus Falc. The finding of elephant remains in the Pliocene mance sands of Italy is not new, but it is rare. A REMARKABLE paper on "The Ethnologic Affinity of the Ancient Etruscans," by Dr. Daniel G. Brinton, was read before the American Philosophical Society on October 18, and has now been issued separately. Dr. Brinton's attention was specially called to the subject during a sojourn of some months in Italy, early in the present year, when he had an opportunity of study ing many museums of Etruscan antiquities. The object of the paper is to prove that the Etruscans probably came from Northern Africa, and belonged to the same stock as the Kabyles, on the borders of whose country Dr. Brinton had spent some time before his visit to Italy. He thus sums up his conclusions:(1) The uniform testimony of the ancient writers and of their own traditions asserts that the Etruscans came across the sea from the south, and established their first settlement on Italian soil near Tarquinii; this historic testimony is corroborated by the preponderance of archæologic evidence as yet brought forward. (2) Physically, the Etruscans were a people of lofty stature, of the blonde type, with dolichocephalic heads. In these traits they corresponded precisely with the blonde type of the ancient Libyans, represented by the modern Berbers and the Guanches, the only blonde people to the south. (3) In the position assigned to woman, and in the system of federal government, the Etruscans were totally different from the Greeks, Orientals, and Turanians; but were in entire accord with the Libyans. (4) The phonetics, grammatical plan, vocaIlary, numerals, and proper names of the Etruscan tongue present many and close analogies with the Libyan dialects, ancient and modern. (5) Linguistic science, therefore, concurs with tradition, archæology, sociologic traits, and anthropologic evinence, in assigning a genetic relationship of the Etruscans to the Libyan family. A LAKE-DWELLING has been discovered in the neighbourhood of Somma Lombardo, north-west of Milan, through the draining of the large turf moor of La Lagozza. The Berlin Correspondent of the Standard, who gives an account of the dis. Livery, says that this "relic of civilization" was found under the peat-bog and the underlying layer of mud, the former being I metre in thickness, and the latter 35 centimetres. The building was rectangular, 80 metres long and 30 metres broad; and between the posts, which are still standing upright, lay beams and half-burnt planks, the latter having been made by splitting the trees, and without using a saw. Some trunks still retain the stumps of their lateral projecting branches, and they have probably served the purpose of ladders. The lower end of these posts, which have been driven into the clay soil, is more or less pointed, and it can be seen from the partly still well-preserved bark that the beams and planks are of white birch, pine, fir, and larch. Among other things were found polished stone hatchets, a few arrow-heads, flint knives, and unworked stones with traces of the action of fire. measured during 101 days, ending with October 1, by means of an anemometer placed at 994 feet above the ground, and compared with the results of a similar instrument at the Paris Meteoro logical Office, placed at 66 feet above the ground. The average velocity on the tower was 16 miles an hour, being over three times the amount registered at the Meteorological Office, where it was only 5 miles an hour. At the lower station the diurnal variation showed a single minimum about sunrise, and a single maximum about 1 h. p.m. On the tower the minimum occurred about Ioh. a.m., and the maximum about 11h. p.m., while the characteristic maximum of lower regions about the middle of the day was hardly perceptible on the tower. It is remarkable that this inversion, which is usual upon high mountains, should occur at so small a height as that of the Eiffel Tower. The ratio of increased velocity was constant at about 5: I between midnight and 5h. a.m.; it then decreased rapidly and became 2:1 at about roh. a.m., and maintained this value until 2h. or 3h. p.m., when it again rose regularly until midnight. These results are of considerable importance to the study of aerial navigation. THE new number of the Mineralogical Magazine opens with an important paper, by Mr. L. Fletcher, F.R.S., on the meteorites which have been found in the desert of Atacama and its neighbourhood. This paper is accompanied by a map of the district. Prof. McKenny Hughes, F.R.S., has a paper on the manner of occurrence of Beekite and its bearing upon the origin of siliceous beds of Paleolithic age. There are also three short papers by Dr. M. F. Heddle, and one by Mr. R. H. Solly. SOME experiments on the photography of the red end of the spectrum, by Colonel J. Waterhouse, appear in the Proceedings of the Asiatic Society of Bengal for April 1889. In order to render the ordinary commercial gelatine dry plates sensitive to the red rays they are bathed for one or two minutes in a solution of I part of alizarin blue (C,-. H. NO4) to 10,000 parts of distilled water with I per cent. of strong ammonia added. Plates treated with this dye show very intense action through the violet and blue regions as far as b; from E to C there appears to be a minimum of action; the sensitiveness, however, increases between C and A, and is strongest between C and B and a to A. Below A the sensitiveness quickly diminishes. Colonel Waterhouse finds that plates saturated with a special preparation of cyanin and sulphate of quinine have their maximum sensitiveness between D and B, but between B and A the action is much weaker than that obtained by using alizarin blue, hence the latter dye is valuable as a ready and simple means of photograph orthochromatic photography, rhodomine was found to be almost as efficient as erythrosin, and to be especially useful for photographing the region immediately about D. The photographs were taken by means of Rowland's plane and concave diffraction gratings. MR. R. ETHERIDGE, JUN., contributes to the Report of the Australian Museum, just received, an interesting appendix on the limestone caves at Cave Flat, junction of the Murrumbidgeeing the spectrum between C and A with ordinary dry plates. For and Goodradigbee rivers, county of Harden. Having recorded the observations made by him in these remarkable caves, Mr. Etheridge offers some remarks on the Murrumbidgee limestone. This, he says, is of a dense blue-black colour. It is much winted and fissured, highly brittle in places, with a hackly | coachoidal fracture, and crammed with fossils, especially corals. As a display of these beautiful organisms in natural section, he has never seen its equal. Large faces of limestone may be seen, with the weathered corals, and particularly Stromatopora, standing out in relief and in section also. Many of these masses of coral, particularly those of Stromatopora and Favosites, are as much as 4 feet in diameter. The Murrumbidgee limestone has been classed as Devonian by the late Prof. de Koninck, but Mr. Etheridge has not yet sufficiently examined the fossils of this deposit either to gainsay or confirm this view. He thinks it not improbable, however, that Prof. de Koninck's view may be correct. THE Comptes rendus of the Paris Academy of Sciences, of November 4, contains a note by M. A. Angot, on the mean hourly velocity of the wind at the summit of the Eiffel Tower, A NEW mode of preparing marganese, by which the metal can be obtained in a few minutes in tolerably large quantities and almost perfectly pure, is described by Dr. Glatzel, of BresA quantity of manlau, in the current number of the Berichte. ganous chloride is first dehydrated by ignition in a porcelain dish, and the pulverized anhydrous salt afterwards intimately mixed with twice its weight of well-dried potassium chloride. The mixture is then closely packed into a Hessian crucible and fused in a furnace at the lowest possible temperature, not sufficient to volatilize either of the chlorides. A quantity of metallic magnesium is then introduced in small portions at a time, the total quantity necessary being about a sixth of the weight of the manganous chloride employed. Provided the crucible has not been heated too much above the melting-point of the mixture of chlorides, the action is regular, the magnesium dissolving with merely a slight hissing. If, however, the mixture has been heated till vapours have begun to make their appearance, the reaction is extremely violent. It is therefore best to allow the contents of the crucible, after fusion, to cool down to a low red heat, when the introduction of the magnesium is perfectly safe. When all action has ceased, the contents of the crucible are again heated strongly, and afterwards allowed to cool until the furnace has become quite cold. On breaking the crucible, all the potassium chloride and the excess of manganous chloride is found to have been volatilized, leaving a regulus of metallic manganese, fused together into a solid block, about three parts by weight being obtained for every two parts of magnesium added. The metal, as thus obtained, is readily broken up by hammering into fragments of a whitish-gray colour possessing a bright metallic lustre. The lustre may be preserved for months in stoppered glass vessels, but, when exposed to air, the fresh surface becomes rapidly brown. The metal is so hard that the best files are incapable of making any impression upon it. It is so feebly magnetic that a powerful horse-shoe magnet capable of readily lifting a kilogram of iron has no appreciable effect upon the smallest fragment. It was noticed that the introduction of a small quantity of silica rendered the manganese still more brittle, and caused it to present a conchoidal fracture, that of pure manganese being uneven. The specific gravity of the metal, former determinations of which have been very varied, was found to be 7:3921 at 22° C. This number, which was obtained with a very pure preparation, is about the mean of the previous determinations. Dilute mineral acids readily dissolve the pulverized metal, leaving a mere trace of insoluble impurity. It is also satisfactory that practically no magnesium is retained alloyed with the manganese, and the introduction of carbon is altogether avoided by the use of this convenient method. THE additions to the Zoological Society's Gardens during the past week include a Common Marmoset (Hapale jacchus) from South-East Brazil, presented by Mr. O. Burrell; a Common Squirrel (Sciurus vulgaris), British, presented by Miss B. Tatham; a Common Stoat (Mustela erminea) from Northamptonshire, presented by Mr. Cuthbert Johnson; a Wattled Crane (Grus carunculata) from West Africa, presented by Mr. Robert Sinclair, Jun. ; a Redshank (Totanus calidris) from Devonshire, presented by Mr. R. M. J. Teil; a White-backed Piping Crow (Gymnorhina leuconota) from Australia, presented by Mr. W. H. Felstead; a Grey-headed Porphyrio (Porphyrio poliocephalus) from India, presented by Dr. Gerard Smith; a Common Chameleon (Chamaleon vulgaris) from North Africa, presented by Mr. G. W. Alder; a Dwarf Chameleon (Chameleon pumilus) from South Africa, presented by Mrs. Leith; a Green Lizard (Lacerta viridis), European, presented by Mr. C. H. Whitlow; a Common Jay (Garrulus glandarius), European, purchased; five Carpet Snakes (Morelia variegata) from Australia, received in exchange. Remarks. (1) Sir John Herschel's description of this nebula is as follows -! Bright, very large, very much extended. The spectrum 2. not yet been recorded. The .. In the ear... (2) This is a star of Group II., in which Dunér recorks har 2-8, but states that they are neither wide nor dark. falls in species 13 of the subdivision of this group, and well advanced towards Group III. Metallic lines, and poss hydrogen lines (dark) may therefore be expected. stages of the group, no hydrogen lines appear, the radiation form the interspaces between the meteorites being balanced by absorption of the gas surrounding the incandescent stones, in the more advanced members, as in a Orionis, the absorpt will probably be found to slightly predominate. The prese or absence of the F line, and of metallic lines, and their relative intensities, should therefore be noted. (3) This is a star of either Group III. or Group V., and th usual criteria (see p. 20) should be observed in order to dete mine which. At the same time, the relative intensities of "*; hydrogen lines and the metallic lines (say and D) shouldi recorded, so that the star may be placed in a line of temperature with others. (4) According to Gothard this is a star of Group IV. Tusual observations are required. (5) Dunér classes this with Group VI. stars, but states the the type of spectrum is a little doubtful. Further observativas are therefore required. As the most advanced stars of the great are very red, the colour of this star indicates that it probably belongs to an early stage of the group, in which the carr bands would be narrow, and therefore somewhat difficult to observe with certainty, in that case traces of b and D might be expected. The colour should also be checked. (6) Gore gives the period of this variable as 3256 days, 158 the range as 7'4-90 at maximum to < 13 at minimum. The maximum will occur on November 30. The spectrum is of the Duner states Group II. type, and belongs to species 9. that the dark bands, especially 7 and 8, are very wide. I several variables of this class (R Leonis, R Andromedæ, &c Espin has observed bright hydrogen lines near maximum, an the question is, Is this common to all the variable stars of this type? As stated with reference to 15 Arietis, under norma conditions the hydrogen lines in the earlier species of the gro are absent, because the interspacial radiation balances the absorption; but if through some cause the temperature increases & maximum, more hydrogen would be driven into the interspaces and radiation would predominate. It may be mentioned that. according to the meteoritic theory, the increase of temperature and luminosity is brought about by the periastrion passage of a secondary swarm through the outliers of the central one. not unlikely that slight variations of colour will take place fres colour should be noted when the spectroscopic observations are maximum to minimum, and it is important therefore that the made. It is A. FOWLER. OUR ASTRONOMICAL COLUMN. OBJECTS FOR THE SPECTROSCOPE. Sidereal Time at Greenwich at 10 p.m., November 21 = 2h. 3m. 21s. 18-31 Feb. 8-21 Mar. 2-6 17-31 April 11-30 May 10 10 1-5 10-26 27 18 July 12-24 June 1-15 15 28-31 The same spot. If the small spots that were seen from May 6-9, and also on May 27, be neglected, it will be seen that there would be a period without spots extending from April 11 to June 15-th is, sixty-six days; but if these small spots be considered we find en interval of twenty-five days without spots-namely, from April 11 to May 5. The minimum period, therefore, appears to have passed about the end of April, this being the time when the greatest number of days passed without spots being observed on the sun. The new period opened with the appearance of a large spot on June 16. RETURN OF BRORSEN'S COMET. The following elements and ephemeris for this comet are given by Dr. E. Lamp in Artronomische Nachrichten, No. 2933 : T = 1890 February 24°1358 Berlin midnight. writes to remind us that Houzeau's "Vade Mecum" was issued after the appearance of the second volume of the "Bibliographie Générale de l'Astronomie," the publication of which began in 1879. Moreover, the "Vade Mecum" was only a second edition of the "Répertoire des Constantes de l'Astronomie," inserted in 1877 in the first volume of the new series of the "Annales Astronomiques" of the Brussels Royal Observatory. The numerous materials brought together for the "Bibliographie Générale " suggested to Houzeau the idea of issuing a new edition of the "Répertoire" considerably corrected and enlarged. A NEW COMET.-A new comet was discovered on November 17 by Mr. Lewis Swift, of the Warner Observatory, Rochester, New York. Place at November 17, 6h. 35m. 2s. G. M. T.; R.A. 22h. 42m. 24s.; N.P.D. = = 78° 9'. Daily motion in R.A., + 2m.; in N.P.D., - 15'. The comet was only faint. MIRAGE IN THE SOUTH AMERICAN 39 428 WAS staying in the Pampas of the Argentine Republic, near Melincue, a small town of the Province of Santa Fe, from September 1888 to March 1889. During my stay I had the opportunity of observing certain mirage phenomena. It is possible that my notes may contain something of interest. They were, designedly, taken without reference to any previous knowledge of the theory of mirage that I might possess. 38 47 4 - 38 28 5 38 93 37 49 8 37 30'1 -37 10'1 - 36 49 8 -36 29°2 36 8:4 35.47'2 35 25.8 - 35 4'1 - 34 42 0 34 196 -33 56 8 53 32.33 336 30... 55 17... - 33 10 o GENERAL BIBLIOGRAPHY OF ASTRONOMY.-The second part of Vol. I. of this comprehensive bibliography has been pubished. It represents Houzeau's last work, and hence it is well that his biographical note, by A. Lancaster, should be included. The first part of Vol. I., published in 1887, contained the references to historical works and those relating to astrology; the part just published contains the references to biographies of astronomers and their epistolary communications, general astronomical works, astronomical societies and their proceedings, and everything relating to spherical astronomy. Works on theoretical astronomy are also well represented. The third and last part of Vol L is now in press, and contains references to all the published matter on the mechanism of the heavens, physical, practical, and descriptive astronomy, and the systems of cosmogony. The utility of this bibliography, when completed, needs no comment. J. C. HOUZEAU'S "VADE MFCUM."-With reference to our biographical note on J. C. Houzeau (p. 20), M. A. Lancaster To illustrate my observations I had drawn eight diagrams; but, for the purpose of insertion in NATURE, I have been obliged to reduce these to two. Hence I fear that my descriptions may not be as clear as I should wish. The most general conclusion at which I arrived was that there were two classes of mirage of very different character. The one I shall call "the summer mirage," the other "the winter mirage." I would observe that, without a telescope of some sort, one would be unable to make observations of much value; and that, as I had but a binocular telescope, in many details I failed to make out as much as I could had I possessed a larger telescope steadily mounted. I. The Summer Mirage. (1) This mirage is seen in full day. I was told that in normal years it is most remarkable in the extreme heat of summer. The summer of December, January, and February 1888 and 1889 was abnormally wet, however. And I myself saw the mirage most frequently in spring (September, October, and the earlier part of November), the grass being then short and very dry. Later on the grass became very long, and unusually green and damp, owing to the heavy rains. And then I saw the mirage but rarely in the grass plains, though on the several occasions on which I passed, in the blaze of a summer day, the dry sandy bed of an old laguna, the mirage was there to be seen very clearly. On one or two occasions in spring I saw the mirage when there full day. was a fairly cold wind and no perceptible sunshine, but still in (2) This kind of mirage usually appeared as a strip of " water running more or less parallel to the horizon, at one end narrowing to a point, and at the other end opening out into the sky. It appeared much as an arm of the sea, or an estuary, seen near the horizon, and running parallel to it. The "water" was of the same colour as the sky above it near the horizon. (3) Viewed through glasses, the whole of the land seen above and beyond the " water," the "water" itself, and to a less extent the land seen just this side of it, appeared wavy and illdefined, flocculent, and (when there was any breeze) possessed of a drifting movement down the wind. At the thin end of the "water," and just beyond it in the line of the layer, one could see broken fragments of "water" drifting over the land; and, in like manner, the peninsula of land appeared to end in a line of drifting fragments. (4) It appeared to me that the land seen beyond the watery layer was either within the limits of the natural horizon, or not much beyond them. One did not, as one did in the "winter mirage," see houses, &c., that were normally out of sight. (5) Cattle, &c., seen in the watery layer were ill-defined. But on the whole it seemed that their legs were hidden, and bodies were reflected inverted, much as if they had been standing in shallow water. |