(680); popular works, almanacs, 657 (642); fine arts, stenography, 627 (584); commerce, 583 (577); classical and oriental languages, archæology, mythology, 533 (481); modern languages, old German literature, 506 (485); agriculture, 433 (421); miscellaneous writings, 423 (378); architecture, railways, engineering, mines, and navigation, 403 (384); bibliography, encyclopædias, 377 (278); geography, travels, 356 (306); war, 353 (337); maps, 301 (300); mathematics, astronomy, 201 (158); philosophy, 125 (139); forests and game, 112 (103); freemasonry, 20 (21).

MESSRS. MACMILLAN AND CO. have in preparation, and will publish this year, A Course of Instruction in Zootomy (Vertebrata),” by T. Jeffery Parker, B.Sc. Lond., Professor of Biology in the University of Otago. The work will consist of full directions for the dissection of the Lamprey, Skate, Cod, Lizard, Pigeon, and Rabbit, and will be illustrated by numerous woodcuts from the author's original drawings.

art.

THE death is announced of Count Alexander Erdödy, a Member of the Pesth Academy of Sciences, vice-president of the Society for Plastic Art, and a liberal patron of science and His death occurred on January 24 at Vep (Hungary); he was eighty years of age. We regret also to announce the death of Herr Gabriel Koch, a Frankfort tradesman and an eminent lepidopterist, whose "Schmetterlingsbuch" has a wide reputation in Germany. He died at Frankfort-on-Main on January 22, aged eighty. On February 2 died Prof. Gorini at Lodi, well known by his works on volcanic phenomena. He was a teacher at the Lodi High School, and one of the warmest advocates of cremation in Italy.

EARTHQUAKES continue at Berne. A new shock, directed from east to west, was felt in the north of the town on February 8, at 5.25 p.m. Shocks of earthquake are reported from Braila on February 11 at 7h. 15m. a.m., and from Galatz at the same time.

IT was not difficult to foresee that the warm weather which prevails now in the Alpine region, together with immense quantities of snow fallen during the previous days, would occasion several avalanches. On February 13 a terrible one descended from the slopes of Mont Pourri, and covered with a mass of snow, thirty feet deep, the village of Brévières, in the Tignes commune. Thirty-two persons were buried under the snow, and no less than three hundred peasants from the neighbourhood were engaged in sinking pits to reach the buried houses. Of the buried, twenty-five were found alive, four were dead, and three are not yet discovered. Two days later, another avalanche descended from the same mountain, and covered a space 10,000 metres wide, with a mass of snow fifteen to twenty metres deep. The pressure of air displaced by the avalanche was so great that all the windows of the village were broken within a few seconds. The quantity of snow fallen during the previous days 'was so great that all communication was broken up between Brévières village and the bottom of the valley; a peasant from Tignes took thirteen hours to reach the next town, Bourg-Saint-Maurice, travelling in the snow more than one metre deep.

THE provincial governments of Navarre and Logroño (Spain) have received the royal sanction to the necessary outlay for constructing and maintaining meteorological stations in these provinces.

OUR ASTRONOMICAL COLUMN ENCKE'S COMET IN 1881.-So far as can be judged without the calculation of the perturbations since 1878 this comet will again arrive at perihelion about November 8 in the present year. In 1848, when the comet passed this point of its orbit on

November 26, it was detected with the 15-inch refractor at Cambridge, U.S., on August 27, as "a misty patch of light, faint and without concentration: its light coarsely granulated, so that were it not for its motion it might be mistaken for a group of stars of the 21st magnitude" (Bond). The theoretical intensity of light at this time was o°21, and we find that, assuming the perihelion passage to occur on November 8, the comet should have this degree of brightness soon after the middle of August next, so that it may be anticipated observations will be practicable with the waning moon about the 20th of that month. The last perihelion passage took place on July 26, 1878, the period of revolution at that time being 1200 ̊58 days according to the late Dr. von Asten. The aphelion distance is 4c879, the perihelion distance 0:3335, and the minor semi-axis I°1675 (the earth's mean distance from the sun = 1). The approach to the orbit of the planet Mercury is still very close (0031) in about 126°5 heliocentric longitude. The nearest approximation of the two bodies that has occurred since the discovery of the comet's periodicity took place on November 22, 1848, when their distance was only o'038. It is known that from his investigations on the motion of Encke's comet, von Asten inferred a much smaller value for the mass of Mercury than had been previously

CINCINNATI MEASURES OF DOUBLE STARS.-Mr. Ormond Stone has issued an important series of measures of double stars made at the Observatory of Cincinnati, which is under his superintendence, between January 1, 1878, and September 1, 1879. The number of stars measured is 1054, of which 622 are south, and 432 north of the celestial equator: 560 belong to Struve's catalogue, 171 were discovered by the Herschels, 162 by Mr. Burnham, and 85 were found with the Cincinnati refractor, which has an aperture of eleven inches. The measures of the southern stars have a special interest, as there are comparatively few previous ones upon record. In his introduction Mr. Stone points out the most notable differences between the Cincinnati measures of angle and distance, and those of Struve, Sir John Herschel, and others; we shall refer to several of these cases in a future column. The volume is published by the Board of Directors of the University of Cincinnati, and will be a necessary addition to the libraries of those who are making the double stars their special study. Mr. Stone acknowledges his obligation to the Manual of Double Stars lately published by Messrs. Crossley, Gledhill, and Wilson, and M. Flammarion's Catalogue des Étoiles Doubles et Multiples en Mouvement relatif certain."

66

THE MINOR PLANETS IN 1881.-The usual supplement to the Berliner astronomisches Jahrbuch (1883), containing its specialty, elements and ephemerides of the small planets for the ephemerides for every twentieth day throughout the year of 210 present year, has been issued. We have in it approximate planets, the latest being No. 217, and accurate opposition ephemerides of 58. Three planets are omitted for want of proper data for computation, viz. No. 99 Dike, No. 155 Scylla, and No. 206 Hersilia. A glance at this long series of ephemerides shows how wide a range over the heavens the apparent tracks of these small bodies present: thus we find Euphrosyne in opposition in 52° south declination, in the constellation Indus, and Niobe in the vicinity of Persei, with 43° north declination. A favourable opportunity for repeating observations for determination of the solar parallax would have been afforded if, in the first place, the actual position of No. 132 Ethra were pretty accurately known, and if Mr. Gill were able to utilise his helio neter at the Cape of Good Hope this planet on February 28 being distant from the earth less than o'84 of the earth's mean distance from the sun, with 47° south declination and rather greater brightness than a star of the ninth magnitude.

CHEMICAL NOTES

Hautefeuille AND CHAPPUIS state (Comptes rendus) that when a high tension spark is passed through a mixture of nitrogen and oxygen, ozone and "pernitric acid' are produced, but the latter compound is readily decomposed with production of a less oxygenated body and oxygen. When the electric discharge is passed through air in presence of water vapour very noticeable quantities of nitric acid are formed. The same observers have examined the absorption-spectrum of ozone and have recognised certain bands which they state are also found in the solar

spectrum. They think that the blue colour of the sky may probably be partly due to the presence of ozone.

BRAME (in Comptes rendus) recommends the use of baryta in place of sodium carbonate and charcoal, in the ordinary dry test for arsenic. If arsenious oxide is heated with baryta a mirror is obtained consisting partly of metallic arsenic, and partly of barium arsenate: the test does not succeed so well with arsenious sulphide.

A CONSIDERABLE deposit of crystallised (octahedral) sulphur has been found under the soil of Paris, where organic refuse matter has long accumulated. The sulphur appears to be a product of the deoxidising action of the carbon compounds present in the refuse on the calcium sulphate of the soil.

M. LOUGHININ continues, in the Journal of the Russian Chemical Society, his interesting researches on the quantities of heat produced by burning alcohols of the allyl series; he publishes in the Journal the figures corresponding to two new bodies of this series (CH2O and C10H20O), which figures, together with those he has already published in the Comptes rendus (vol. xci.), allow him to draw a complete table of the calories disengaged by the whole of the alcohols of this series.

THE first number of the Gazetta Chimica Italiana for the present year is devoted, with the exception of a paper by M. Fileti on gas analysis, to papers on organic chemistry: these include work on Camphor Derivatives by Schiff; on Picrotoxin by Paterno and Oglialoro; and on Synthesis of Aromatic Aldehydes by the use of Chromyl Dichloride, by Paterno and Scichiloni.

IN the course of a paper on the Photo-chemistry of Silver Chloride, Eder states (in Wien. Akad. Ber.) that this substance is more sensitive to light when substances which absorb chlorine are present, than when in the pure state. To develop the latent image he recommends especially ammonium ferrocitrate, and hydroquinone along with ammonium carbonate.

By the action of potassium dichromate and sulphuric acid on caffeine, Hinteregger has obtained as much as 40 per cent. of dimethyl parabanic acid, and 39 per cent. of the monomethyl

acid from theobromine.

IN a little mathematical note in the Comptes rendus M. Thollon investigates the general equation for the passage of light through a prism, and thence deduces the proposition that for every prism there is an angle of minimum resolving power. Differentiating the general equation with respect to the index of refraction, he obtains, first, a differential equation expressing the dependence of the angular distance between two rays upon the dispersive A separate differentiation with respect to the angle of incidence yields a second differential equation expressing the dependence of the apparent width of the slit as seen through the prism upon the angular aperture of the slit, as viewed from the prism through the collimator. Hence a relation can be obtained between the angular distance between two rays and their apparent

index.

breadth. Further examination of the equations shows that for a certain incidence there will be a minimum of resolution (i.e. an incidence at which the rays are least well defined), and that for another incidence there will be a minimum of dispersion; these two incidences being symmetrically related to the angle of incidence corresponding to minimum deviation. M. Thollon states that these deductions may be readily verified by the following experiment:-A dense flint glass prism is adjusted in the position of minimum deviation for the rays D upon its supporting table in the spectroscope, lit by a sodium flame. The slit is then narrowed or widened until the two yellow rays are just in mutual contact. On then turning the prism around its axis so as to increase the angle of incidence the two rays are seen to separate and to become perfectly distinct, the angular distance between them diminishing all the while. But if the prism be turned in the opposite direction, so as to decrease the angle of incidence, the yellow band is seen to become wider, but without being resolved into two rays. Perhaps this research may explain why the so-called "half prism" spectroscope failed to realise allthe hopes of its inventor.

RECENT observations by Hrn. Wüllner and Grotrian (Wied. Ann. No. 12) seem to prove that the specific volume of vapours is independent of the size of the space in which it is determined. They also confirm Herr Herwig's result, that vapours always undergo precipitation before reaching the socalled maximum tension. Further, the tension at which condensation begins is found to have a relation to the maximum tension, which depends on the nature of the liquid, but is nearly independent of the temperature. Experiments made in order to find in what measure vapour must be compressed so as to present maximum tension, gave the unexpected result, that there is in general no maximum tension in the sense hitherto accepted; but that the tension of saturated vapours, even when they are in contact with a large and excessive quantity of liquid, is perceptibly increased by compression.

THE varieties of the electric discharge in gases are fully No. 12). The chief conclusion is that there are four wellinvestigated by Herr Lehmann in a recent paper (Wied. Ann characterised modes of discharge to be distinguished, viz. glow, brush, band, and spark discharge; and these may all be obtained in air of ordinary (as well as of less) density, and also in other gases, with inserted resistances and breaks, and with sharp and rounded form of electrodes, at great or small distances. The principal characteristics are these:-1. Glowdischarge; positive glow, negative light pencil, consisting of two parts separated by a dark space. 2. Brush-discharge; positive brush, consisting of stem and branches; negative light-pencil. 3. Band-discharge; positive light with two places of intermittence, sometimes stratified, and separated from the negative glow by a dark space. 4. Spark-discharge: band of light connecting both electrodes; with two places of intermittence, brushes of metallic vapour at both ends, the positive longer, the negative thicker; sometimes oblique dark spaces.

THE influence of traction and vibrations of a metallic wire on its electric conductivity is the subject of a paper by Dr. De Marchi in the Reale Ist. Lomb. Rend. (vol. xiii. fasc. xix.). The results he arrives at are summed up thus: 1. Any traction of a metallic wire increases in general its resistance; when the traction is very slight however there is diminution instead of increase; with increase of traction the case comes under the general law. 2. In general the increments are proportional to the increments of traction, up to a certain limit, beyond which the variations of resistance are manifested in sudden bounds, indicating an instan taneous and profound perturbation of the molecular state of the wire. 3. The law of increments of resistance is apparently independent of that of the elongations. 4. Any vibration of a wire is accompanied by a variation of resistance generally very perceptible. In most cases there is decrease of resistance if the vibration be sonorous, and more so if harmonic; increase, if the vibration be silent. This last law however requires confirmation.

IT is known that M. Plateau distinguishes between an internal and a surface viscosity of liquids, a distinction which Signor Marangoni does not consider warranted. Herr Oberbeck (Wied. Ann. No. 12) has approached the question experimentally thus: A brass cross is hung bifilarly with two platinum wires by one arm; its horizontal arms carry weights whose positions can be varied by screwing, so as to vary the swing; it carries a mirro reflecting a scale, and to the lower arm is attached a thin plat

or cylinder of brass to swing in the liquid at various depths. The whole can be raised or lowered with a micrometer screw, and it is thrown into slight oscillation by means of a magnet. A rectangular glass vessel is used for the liquid. The author finds that with distilled water the resistance increases suddenly and to a quite considerable extent whenever the upper edge of the plate comes into the free surface, and he does not doubt this is due to increased friction in the surface layer. The increase of resistance from the last previous position of the plate was 60.9 per cent., and with four aqueous salt solutions there was also an increase, varying between 75°1 to 54°1 per cent. Precautions adopted to prevent the presence of foreign particles on the surface (filtration, covering with moist filter-paper, &c.) had hardly any influence on the values. Long-standing of the liquid increased the surface-resistance, and stirring then diminished it; still it was always considerable at first. With M. Plateau, Herr Oberbeck found a decrease of resistance at the surface in some liquids; this was comparatively small (alcohol 119 per cent., oil of turpentine 12.6, sulphide of carbon 26.3, &c.). A small addition of alcohol to water lessens its surface-resistance property in a marked degree, and with further addition the mixture behaves like pure alcohol.

IN a paper on dew and fog (Zeits. für Meteor. Bd. xv. p. 381) Herr Dines, from observations of the former with watchglasses exposed on different substances at night, estimates the annual dew formation to be about 35'5 mm. (on grass, 26 mm.); at the best 38 mm. The average nightly dew (in 198 observa. tions) was hardly o'I mm. ; in a few cases o°3 mm.; average on grass 0'07 mm. Morning fog along a river course arises when the water is warmer than the air over it. The evaporation goes on more quickly than the vapour can be carried away; hence the latter is condensed and spreads as fog (similarly with fogs over the Gulf Stream). The evening fog on moist low-lying meadows is due to the fact that the grass surface cooled by radiation cools the lowest air-layers, so causing condensation of the aqueous vapour. The fine drops of dew, Herr Dines estimates, are about o'oor mm. in diameter; while the finest rain-drops have a diameter of 0'3 to 0°33 mm. The particles of fog vary in diameter from o'016 to 0°127 mm.

THE colour-changes presented in the microscope by various substances (chiefly mineral) of uneven surface, when immersed successively in liquids of different refracting power, have been made by Herr Maschke (Wied. Ann. No. 12) the basis of a method of distinguishing substances. Such changes may be had, e.g. with small glass particles, observed in water, in oil of almonds, and in mixtures of the latter with oil of cassia. The dark and the bright parts of the image show different series of colours. That the effects are simply due to prismatic action of the object appears from the fact that they may be got without the microscope, by looking_e.g. through a tube at a piece of rockcrystal in water, &c. For mineral objects Herr Maschke used five liquids; amylic alcohol and glycerine, besides the three just named. By various mixtures of these a series of liquids is obtained, giving any desired index of refraction from 1333 to 1606. (Coloration begins when the refraction of the liquid is near that of the object; when the former greatly exceeds the latter a certain stability of colour appears.) The method is not applicable to bodies opaque in the microscope, or having too strong colours of their own; nor yet to bodies having a greater index of refraction than oil of cassia. It may, too, prove difficult sometimes to find a liquid sufficiently indifferent to the object. Herr Maschke indicates how the refractive indices of substances may be compared by his method, and (a more difficult task) numerically determined. He also gives a number of his own determinations.

AN interesting study, by Herr Holtz, of the electric discharge in insulating liquids appears in Wiedemann's Annalen, No. 12. Among other results the length of spark is found hardly at all dependent on quantity or on retardation of the discharge. Naturally it differs in different liquids, but only in one liquid (sulphuric ether) did it increase with velocity of rotation of the disk (this appears to be due rather to the mode of preparation than to the nature of the liquid). As in air, with dissimilar electrodes, the spark-length is conditioned by the polarity of the electrodes. The thickness, sound, and luminous force of the spark depend chiefly on the electric quantity and the retardation. The spark is thinner than in air, but brighter (brightest in sulphide of carbon, least bright in olive-oil and ether). It is more crooked than in air. Throughout its length it shows innumer

able very small dark spaces. With large striking distance it appears within a largely-branching brush. (The appearances of the brush discharge, get best in petroleum, are also described.)

FROM data obtained in various parts of Germany, Austria, and Switzerland (Wied. Ann. No. 12), Herr Holtz finds a wellmarked increase in risk from lightning in these parts since 1854, while no such increase appears in the number of thunderstorms. Hence he infers the causes to be telluric, and he suggests as probable causes the clearing of forests and increase of railways (attracting storms more to towns and villages); further, the increased use of metal in buildings.

PROF. BOMBINI has lately communicated to the Bologna Academy an interesting paper on spherohedry in crystallisation (Riv. Sci. Ind. No. 21), by which he means any known manner

of production of a fibrous-radiate structure. From a survey of facts he concludes that the great phenomenon of crystallisation comprises two different orders of attractive energy. In the first there is simple centralised attraction, with concurrence of the elements attracted to a common centre. In the second there is attraction with directive polarity according to certain axes of symmetry, and concurrence of the attracted elements towards nodal points in a certain reticular system. Between these two kinds of crystallogenic action there are many gradations, or rather syntheses, superpositions. Further, the correlations between the sphericity characteristic of the liquid state; the spherohedry of globosity with radiated structure; the isometry of radiate pseudocubical groups; leading from the amorphous state of liquids to the absolutely reticular state of the true crystals (isotropic, orthoprismatic, and clinohedric) confirm the cubicity of the first system, and at the same time point to some further significant terms in the progressive series of the physical states of inorganic matter. Prof. Bombini indicates three con. ditions: I. Spherohedric crystallisation; II. Polyhedric crystallisation; and III. Pseudocubic, &c., crystallisation. The third may be considered intermediate between the first and the second; the first appearing as a term of transition between the sphericity of the liquid state and the polyhedry of physical solidity.

GEOGRAPHICAL NOTES

THE February Proceedings of the Geographical Society opens with Capt. Holdich's paper on the "Geographical Results of the Afghan Expedition"; but of more importance from a geographical point of view are Mr. Wilfred Powell's "Observations on New Britain and Neighbouring Islands." The latter is accompanied by a sketch-survey of the north-east portion of New Britain by the author, which of itself is of considerable value. A correspondence between Admiral Ryder, Naval Commander in-Chief at Portsmouth, and the Council of the Society follows, by which we learn that the latter, in declining his offer to establish certain medals, are of opinion that "the plan of granting medals to officers and seamen for independent surveys is impracticable," and further that they do not consider it their business to take any action in regard to an international congress of hydrographers.

UNDER the title of "Union Géographique du Nord de la France," a geographical association was formed some time ago, with its head-quarters at Douai, and branches at Amiens, Arras, Boulogne, Cambrai, Charleville, Dunkerque, Laon, Lille, St. Omer, St. Quentin, and Valenciennes. In the first part of the Bulletin of the Union, which has been sent to us, the list of members covers about fifty pages. The object of the association is by every means to promote the development and spread of geographical knowledge, investigating specially questio s relating to the industry, commerce, and agriculture of the region of the Nord. The Bulletin, a volume of some size, contains papers on the Exploration of the Sahara, Nordenksjöld's last voyage, a Project for Exploring the Wellé, the Proposed Canal between the Atlantic and the Mediterranean, and the Maritime and Commercial Statistics of Dunkerque. In the Comptes rendus of the meetings of the various societies are abstracts of papers on a great variety of subjects, and there are besides a geographical chronicle and a pretty full bibliography. We have no doubt the Association will do much good in the North of France.

PROF. UJFALVY bas left St. Petersburg on his return from Central Asia. The journey he made during last summer was not so successful as his preceding travels, because of a serious

illness which kept the traveller in his bed for more than two months. Nevertheless the ethnographical collections brought in are very interesting.

THE Smolensky Vestnik gives the following information as to Colonel Prjevalsky. He was born on April 12, 1839, at the village of Otradnoye, in the Smolensk district. His mother and his old nurse, both still alive, were the first who inspired him with a warm love of nature, and his life, on the estate of his mother, contributed to the development of this love. He studied at the Smolensk College (gymnasium), and notwithstanding the desire of his mother, who wished him to enter a university, he entered as a sub-officer in the Polotzk infantry regiment. Promoted to the grade of officer, he went to the military academy, and soon we find him as an officer during the Polish campaign, and afterwards as a teacher of geography and history in the cadet school at Warsaw. A keen hunter, he could not stay long in a city, and he soon undertook a journey to the Oussouri. This determined his ultimate career; the richness of the fauna and the pleasure of hunting in uncivilised countries determined him to undertake further journeys, first to Southern Mongolia, then to Lob-nor, and finally to Tibet, which he reached last year.

UNDER the title of "The Expiring Continent," Mr. A. W. Mitchinson gives an account of his travels in Senegambia, mainly of journeys he made up the rivers Senegal and Gambia. The work contains no dates, thus detracting somewhat from its scientific value, and abounds with speculations and reflections on all sorts of subjects connected with Africa. His notes on what he saw during his journeys are of value as showing the recent con. dition of the country visited, and, as may be inferred from the title, the author's views are rather desponding. His inference from his observations on the small district visited by him, that the African continent as a whole is "expiring," is far too sweeping. While like the other continents it contains "desert places," the bulk of it, so far as we know it, is capable of the greatest industrial development. That its waters are drying up as a whole there is no reason for believing; but evidently in this and in other respects there is ample room for trustworthy scientific examination. The publishers are Allen and Co.

THE February number of Petermann's Mittheilungen begins with a paper on the Chukchis on the shores of the Arctic Ocean, their number and present position, based on two articles by O. Nordqvist and Lieut. Hovgaard. Dr. Gustav Radde contributes the first part of a narrative of his journey to Talgsch, Aderbeijan, and Sawalan in 1879-80. From the papers in the North American Review a long account is given of M. Désiré Charnay's explorations of the ruins in Central America. There is an elaborate and detailed map, with accompanying text, illustrating Dr. Junker's journey through the valley of the Chor Baraka, in the Egyptian province Taka in 1876.

MESSRS. W. AND A. K. JOHNSTON have sent us the first two parts of a "Statistical Atlas of England, Scotland, and Ireland," by Mr. G. Phillips Bevan. These two parts include Religious and Educational Statistic, and subsequent parts will be devoted to Industry, Crime, Marine, Agricultural, Railways, Geology, and Mining, &c.; there will be fifteen parts in all. In the first two parts a vast amount of useful statistics are graphically exhibited on the maps, and systematically arranged in separate tables. Much of the information thus exhibited could not be obtained from any other single source.

No. 90, the concluding part of the fifteenth volume of the Zeitschrift of the Berlin Geographical Society, contains the conclusion of the late Dr. Erwin von Bay's interesting journal of his journey from Tripoli to Ghât and Air, and a paper on the region which caused the recent contest between Chili and Bolivia, by Dr. C. Marten. The rest of the number, 130 pages, is occupied with the bibliography of the past year, one of the most valuable features of this most important of geographical journals. The bibliography is practically exhaustive, is arranged in a thoroughly systematic manner, and includes works relating to all departments of geography.

M. SIBIRIAKOFF has safely returned to St. Petersburg, where he had a brilliant reception. At a meeting of the Society for the Furtherance of Russian Commercial Navigation, M. Sibiriak off pointed out the grave errors contained in Russian marine charts, which caused two of his captains to mistake the Gydan Bay for the Yenisei Estuary. They entered it on September 12, and soon met with thick-packed ice. The Nordland had stopped at once, the Oskar Dickson proceeding some 100 versts further to the

south. Thence the travellers had journeyed to Obdorsk, with Samogedes as guides.

THE Rüppell fund at Frankfort-on-the-Main, which was founded in honour of the Nestor of African travellers, Dr. Eduard Rüppell, and for the exclusive object of supporting scientific exploration, consisted of the sum of 35,570 marks (1770%.) at the end of last year. From this the Senkenberg Naturforschende Gesellschaft, at their last meeting, granted the sum of 3000 marks (150/.) to Dr. Wilhelm Kobelt of Schwanheim, an eminent conchologist. Dr. Kobelt is now engaged upon the investigation of the existing and fossil molluskan fauna of the Mediterranean, and had during the last few years repeatedly visited Italy and Sicily for this purpose. His next tour, which is to extend from March to September, will comprise Spain, Algeria, and, if possible, Morocco. We may remind our readers that the journeys of Drs. Noll and Grenacher to Spain and the Canary Islands in 1871, as well as those of Verkrüzen to Newfoundland in 1874 and 1875, were also largely supported by grants from the Rüppell fund.

GEODETICAL measurements will be begun next spring on the stretch between Great St. Bernard and the St. Gothard for connecting together the Italian and the Swiss geodetical network.

A NEW expedition will start, next spring, for the exploration of the Obi, under the direction of M. Moïséeff. Six pupils of the Marine School of Arkhangelsk will accompany him.

THERE is some talk of uniting the three geographical societies of Switzerland, those of Berne, Geneva, and St. Gall, as well as those which may be created afterwards, into one great Swiss geographical association, which will have a central committee and an annual general assembly devoted to the study of geographical questions, and especially of those which have a commercial interest.

UNDER the title of "Das Frauenleben der Erde," illustrated by A. von Schweiger-Lerchenfeld, A. Hartleben of Vienna has published a highly interesting description of the social life of the women of all nations. The work contains much that is of ethnographical value, and the numerous well-executed illustrations, as well as the attractive style of the text, are likely to render it of popular interest.

THE Austrian Section of the German and Austrian 'Alpine Society held its annual meeting at Vienna, on January 26 last. The Section now numbers 1302 members.

ON January 29 a branch of the Berlin "Centralverein" for commercial geography was formed at Düsseldorf. The new branch is directing its main attention to South Africa.

IN the place of the late Dr. Mook, Dr. Manthey has joined the Riebeck expedition, which will leave Cairo in the course of a few days, and will, first of all, proceed to Socotra by way of Aden.

ABNORMAL VARIATIONS OF BAROMETRIC PRESSURE IN THE TROPICS AND THEIR RELATIONS TO SUN-SPOTS, RAINFALL, AND FAMINES

MR. F. CHAMBERS, in his valuable and highly interesting article (vol. xxiii. p. 88) under the above title, has made an important step towards placing the relation between secular weather changes and sun-spots on a more substantial basis than it has hitherto occupied. This has been mainly effected by his employing the most reliable data we at present possess of the latter phenomena, thereby bringing the salient features of their minor variations for the first time into direct comparison with a definite meteorological element, which, it may be remarked, possesses the distinct advantage of representing the integrated effect of changes occurring throughout the entire atmospheric envelope.

He has also shown how the remarkable lag which takes place in the occurrence of the critical barometric epochs at the more easterly stations may be utilised to previse famines from a knowledge of what is going on at more westerly ones.

This however would only be practicable if we knew for certain that famines in all the districts mentioned. invariably took their rise from one set of conditions, such as failure of the usual summer rains, preceded and accompanied by high barometric pressure. In attributing the majority of the famines occurring within the tropics to such a proximate cause, Mr. Chambers

would no doubt be correct; but this relation between pressure and rainfall, strange though the fact may appear, does not apparently hold in the winter in the sub-tropical region of Northern India, nor is famine always caused in this region by a failure of summer rain alone.

For as Mr. S. A. Hill has shown in a paper on "Variations of Rainfall in Northern India" ("Indian Meteorological Memoirs," No. vii. p. 204), a heavy winter rainfall generally coincides with a high barometric pressure over Northern India, and vice versa, while two of the most severe famines in Mr. Chambers' list, viz., those of 1837-38 and 1860-61, in Northern India were caused by a partial failure of the summer rains, followed by an almost complete absence of the usual winter fall."

It is straining the evidence therefore to attempt to relate the e famines, as Mr. Chambers has done, to the previous occurrence of high barometric pressures, since if the law just quoted held good, the famine of 1860-61 was mainly due to the absence of winter rain, caused by the low pressure which observations show actually existed at that time, and the same was very probably the case in 1837-38, a strongly-marked epoch of sun-spot maximum.

It has moreover been shown by Mr. Hill in the paper just referred to that "the summer rains of the North-West Provinces and Rajpootana have failed quite as often when. sun-spots were numerous as when they were few, but whereas in the former case a comparatively slight scarcity has generally been developed into a severe famine through the failure of the winter rains, this has seldom happened in the latter case, the distress at such times being alleviated by the in-gathering of the rabi harvest, rendered more abundant than usual by a copious winter fall." This saving clause with respect to the winter rainfall of Northern India does not unfortunately apply to Southern India, where failure of the usual monsoon supply means drought and probably famine until the next monsoon, e. for an entire year.

On the whole it is plain that high and low atmospheric pressures differ specifically in their effects in different parts of the Indian peninsula, since while the former is generally a sociated with drought in the southern provinces, the latter in the winter is almost equally fatal in the northern provinces. If therefore the future prevision of famines is to be based on the empirical law connecting high barometric pressure with the occurrence of drought and famine, propounded by Mr. Chambers, it must be remembered that this law strictly applies only to regions where the annual water-supply is dependent upon the monsoons alone, and therefore lying for the most part between the two tropics.

It may be remarked that at least half of the Indian peninsula lies north of the tropic of Cancer.

Though I am sceptical as to the idea of motion from west to east, conveyed by the existence of a lag at the more easterly stations, this in no way affects the possibility of prevision as long as the lag remains fairly constant. I am therefore of opinion that in regard to this question the evidence furnished by Mr. Chambers is exceedingly valuable, and that so long as districts are only taken into account that lie within the tropics, such as Southern India, the possibility of prevising famines by noting the occurrence of barometric maxima at more westerly stations may in time be accomplished. For Northern India, and probably other similar sub-tropical regions, the matter is at present more complicated. E. DOUGLAS ARCHIBALD

P.S. In the preceding letter I have only dwelt upon the limitation to be applied to Mr. Chambers's conclusions in the case of Northern India. It is obvious however that there are at least two distinct difficulties to be explained, before they can be finally accepted, even for countries within the Tropics, viz. (1) Why the barometric waves should commence on one meridian rather than on another, and (2) if, as Mr. Chambers thinks, the waves of pressure travel slowly round the earth, why they do not reappear at the place where they started after an interval of

stations, could only be utilised to previse famines if we knew for certain that famines in those districts to which the method is applied invariably took their rise from one set of conditions, such as failure of the usual summer rains, preceded and accompanied by high barometric pressure. It appears to me, however, that if the variations of the rainfall can be definitely related in any manner to the corresponding variations of the barometric pressure, there is no necessity for such a limitation. If, for instance, in Northern India, "a heavy winter rainfall generally coincides with a high barometric pressure, and vice versa," as Mr. Archibald seems prepared to admit, then the occurrence in the winter of a high pressure would portend a heavy winter rainfall, and vice versa, and in this case the failure of the winter rains might be foreseen by observing the progress eastward of the barometric minima.

But I am not aware that the relation above mentioned between the barometric pressure and the winter rainfall of Northern India has yet been worked out with sufficient definiteness for the purpose in view, for although there does appear to be some evi dence in favour of that relation when the average pressure and the total rainfall of the whole winter are taken into account, yet on the other hand it is now known that the short rainy periods of the winter are periods of relatively low pressure. It is not improbable that these periods of low pressure, and the rainfall which accompanies them, are connected with the feeble cyclonic disturbances which (as appears from the charts of stormtracks published by the American Government) óccasionally enter the north-west of India in the winter months and travel down the Ganges Valley sometimes as far as Bengal. The facts concerning these winter rains seem to accord far better with this view of their origin than with the old notion of their connection with the upper anti-monsoon current, an idea which I observe has now been abandoned by Mr. Blanford, the Meteorological Reporter to the Government of India, although up to a recent date it was still retained by some other Indian meteorologists. The question is as yet involved in much obscurity, and I must, with the above suggestion, leave it to be dealt with by those more immediately concerned.

But whatever the relation between the winter rainfall and the barometric pressure may be, I cannot help thinking that Mr. Archibald attaches an exaggerated relative importance to these winter rains, for, from the register of Allahabad, the capital of the province, it appears that the winter rain amounts on the average to only 1'54", whereas the average summer rain amounts to 36 84". And similarly at Delhi, the average total winter rain is only 3'01", while that of the summer is no less than 24*60′′. Such being the case, I think it would be difficult to prove that "the famine of 1860-61 in the North-West Provinces was mainly due to the absence of the winter rain," more especially as the summer rain of 1860 in that province was deficient to the extent of nearly one-half, the fall having amounted to only 54 per cent. of the average.

Neither does it seem clear why the methods of forecasting the general character of a coming season, which are suggested in my paper, should of necessity be applicable only to intertropical regions. It is true that I have dealt only with barometric data furnished by stations lying within the tropics, but my only reason for doing so was that there seemed a better prospect of obtaining definite results from the records of tropical stations, where the weather is generally of a comparatively settled character, than from those of stations situated in extra-tropical regions, where the weather is generally more disturbed. Indeed I am not without hope that the results I have obtained will induce European meteorologists to take up the subject with a view to the possibility of prevising the general character of coming seasons in Europe from observations recorded in America. FRED. CHAMBERS

STANDARD THERMOMETERS

in Mr. Chambers's paper). At present there does not appear to be the slightest evidence to show that they reappear at all, and if they do not, when and where do they disappear?—E. D. A.

MR. E. D. ARCHIBALD states in his friendly criticism of my 66 Abnormal Variations of Barometric Pressure in the paper on Tropics, and their Relations to Sunspots, Rainfall, and Famines," that the occurrence of a decided lag in the barometric movements at easterly, as compared with westerly

forward you the enclosed Memorandum on Standard Thermometers, and to request on their behalf that you would be so good as to publish it in NATURE if you consider it suitable for insertion. G. M. WHIPPLE Kew Observatory, Richmond, Surrey, February 9

DR. LEONARD WALDO has recently communicated to the American Journal of Science an article entitled " 'Papers on Thermometry from the Winchester Observatory of Yale College."