more important discoveries of the last six years, and to make ach general improvements as he has thought likely to be of enefit to his readers.

THE April number of Natural Science, the new monthly reFiew of scientific progress, has articles on factors in the evoluion of the Mammalia, by Prof. C. Lloyd Morgan; some salient Coints in the study of mammals during 1891, by R. Lydekker; he physical features and geology of Borneo, by F. H. Hatch; great lakes, by Clement Reid; life-zones in Lower Paleozoic rocks, by J. E. Marr, F. R. S.; and a new group of flowering plants, by A. B. Rendle.

MESSRS. KEGAN PAUL, TRENCH, TRÜBNER, AND CO.

have issued a second edition of Mr. B. H. Chamberlain's "Things Japanese." The work consists of a number of independent articles, arranged alphabetically, and giving an account of the Japanese people, their country, their ideas, and their industries. It has been enlarged by the insertion of over twenty new articles, while the old have been corrected up to date, and re-written in many parts. The style is compact, fresh, and lucid, and at the end of the more important articles the author gives a list of books in which further information may be obtained. Several subjects have been intrusted to specialists. Prof. Milne contributes the article on "Geology," and Mr. Mason those on "Telegraphs,' ‚”“Chess,” and the game of "Go." THE "School Calendar" for 1892 has been published, this being the fifth year of issue. Mr. F. Storr, referring in the preface to the movement for the registration of teachers, notes that head masters who have hitherto ignored or sneered at the teaching diplomas of the University of Cambridge are beginning to send up their assistants for the examinations of the Syndicate,

or even to enter themselves.

THE new number of L'Anthropologie (tome iii., No. 1) opens with an interesting paper on A. de Quatrefages, by Émile Cartailhac. The paper is followed by a useful list of the principal publications by M. de Quatrefages. M. Marcellin Boule contributes some excellent notes on the formation of fossiliferous deposits in caves. There are also papers on the tumulus-dolmen of Marque-Dessus (commune d'Azereix, Hautes-Pyrénées), by General Pothier; on the respective association of anthropological characters, by Dr. R. Collignon; and on the ethnological position of the peoples of Ferghanah, by Paul Gault. THE U.S. Geological Survey has lately issued a number of important papers in its series of Bulletins. One of them (No. 69) contains a classed and annotated bibliography of fossil insects; another (No. 71), an index to the known fossil insects of the world, including Myriapods and Arachnids. gives the altitudes between Lake Superior and the Rocky Mountains; No. 74, the minerals of North Carolina; No. 75, a record of North American geology for 1887 to 1889 inclusive; No. 79, an account of a late volcanic eruption in Northern Carolina, and its peculiar lava. No. 76 is the second edition of a dictionary of altitudes in the United States.

No. 72

WE have received Parts 41 and 42 of Cassell's "New Popular Educator." Both, like the previous parts, are carefully illustrated. In addition to the cuts introduced into the text, Part 41 has a coloured picture of "the Spectre of the Brocken," and Part 42 a coloured map of the Balkan Peninsula.

THE Hunterian Oration, delivered by Dr. J. Hutchinson, F.R.S., in the theatre of the Royal College of Surgeons on February 14 last, has now been published by Messrs. J. and A. Churchill.

THE additions to the Zoological Society's Gardens during the past week include a Macaque Monkey (Macacus cynomolgus 8) from India, presented by Mr. F. D. Lyon; a Rhesus Monkey

(Macacus rhesus) from India, presented by Mr. J. G. Wythe; a Brush Bronze-winged Pigeon (Phaps elegans ?) from Australia, presented by Mr. H. H. Sharland, F.Z.S. ; two Red Kangaroos (Macropus rufus) from Australia, deposited; two Great American Egrets (Ardea egretta), two Snowy Egrets (Ardea candidissima) from America, two Buff-backed Egrets (Ardea russata), European, purchased; an Eland (Oreas canna 8), born in the Gardens.

OUR ASTRONOMICAL COLUMN.

THE PLANET JUPITER.-During the last year or so the planet Jupiter has been the subject of many observations both at home and abroad. The curious markings that become visible from time to time have been very carefully watched, and the changes which they have been seen to undergo likewise recorded. Those who take a special interest in these observations will find in L'Astronomie, under the title of "Recent Discoveries on Jupiter," a most excellent article written by M. Camille Flammarion. The author, after giving a description of the general state of the planet that can be gathered from a telescopic and spectroscopic survey of his surface, adds a résumé of the important observations made by M. Terby, at Louvain, which were originally addressed to the Belgian Academy. Many very important facts relating to the positions which the dark and light spots take up are here collated, and the numerous illustra tions impress one strongly with the vastness and rapidity of the changes that are continually in progress.

Astronomy and Astro-Physics for March contains also some notes on this planet, communicated by Mr. H. C. Wilson, of the Goodsell Observatory, who, armed with a 16-inch equatorial during the winter of 1891, completed many sketches, some of that as the dark belt approached the great red spot which is situated just north of it, the latter appeared to force it to one side, "there being always a very narrow line of white between the belt and spot." This fact seems to show that, whatever the clouds in close proximity to it. the spot may be composed of, it has the power of dissipating

which are here exhibited. These observations seem to indicate

THE OBJECTIVE PRISM.-Prof. Pickering, in the March number of Astronomy and Astro-Physics, communicates a very interesting article relative to the method of photographing the spectra of the stars with an objective prism. As an account of this method has already been described in these columns in the Draper Catalogue," it is unnecessary for us to enter into the review of the catalogue published under the name of "The details again. At the latter end of the article he mentions also that "a still further advance will be made with the great photographic telescope, the gift of Miss C. W. Bruce." This instrument is stated to be similar to the "Bache telescope," but three times as large, having an aperture of 24 inches. spectra of stars down to the 10th and 11th magnitude are expected to be obtained with it. The engraving which accompanies the text illustrates the method of attaching the large prism to the object-glass end of the telescope.

The

VARIATION OF LATITUDE.-Dr. B. A. Gould, in the Astronomical Journal, No. 257, presents us with some of the work which he has been undertaking with regard to the periodic variation of the latitude at Cordoba, from observations made with the meridian circle. The results obtained by Dr. Chandler showed that by assuming a period of fourteen months, the variations in the latitude, determined between the years 1860 and 1875, could be accounted for. Dr. Gould thought that the same period might be found to satisfy the Cordoba subject of the present inquiry. Owing to the fact that this numobservations, and the computations that he has made form the ber of the Journal does not contain the whole of the work (the latter part of which will be concluded in the next one), we are not able to give the results which he has obtained, but we can mention a point that seems of importance, and which tends to corroborate Dr. Chandler's results.

In a table showing the mean excess of the calculated, above the observed, declinations, the author remarks that "there are two facts which attract attention: first that the times of maxima and minima of the curve are approximately coincident with those deduced by Dr. Chandler from contemporaneous observations in other places; and, secondly, that the corresponding

periodical fluctuations of the curve are markedly inferior to other and larger variations upon which they appear superposed. . . The range included between these extremes amounts to two seconds, and is altogether too large to be attributed either to personal equation or to any instrumental origin."

THE DISCOVERY OF NEPTUNE.-During a visit to England, in 1876, Prof. Holden was frequently with Mr. Lassell, and he then learned a circumstance connected with the discovery of Neptune which is not without interest. Now that Adams and Lassell are both gone, Prof. Holden has published the brief notes he made at the time, as a contribution to the history of the great discovery. It is well known that, in October 1845, Adams submitted to the Astronomer-Royal his computations indicating the existence of an unknown world beyond Uranus. The work was shown to Dawes, and he was so much impressed by it that he wrote to Lassell, asking him to search for Neptune in the region designated by Adams. Had the discoverer of the two inner and faint satellites of Uranus, and the satellite of Neptune, directed his 2-foot reflector to this region, there is little doubt but that the planet would have been picked up. However, the Fates ordained otherwise: Lassell was confined to his sofa by a sprained ankle, and, when he recovered, the letter of Dawes, giving the predicted place of Neptune, could not be found. It turned out to have been destroyed by a toozealous maid-servant. Thus, "by a set of curious chances, the new planet was never looked for by the then most powerful telescope and most skilful observer in England. It was not until many months after the letter of Dawes to Lassell that the planet was found by Galle and D'Arrest, near the position given by Leverrier.

ASTRONOMY AT THE PARIS ACADEMY, MARCH 21.-At the meeting of the Paris Academy of Sciences, on March 21, M. Lewy presented a picture of the Orion Nebula obtained at Toulouse Observatory, with an exposure of five hours, on February 24, 25, and 26.

M. Bigourdan observed Swift's comet on March 17, 18, 19, and 20, and determined its position. He describes it as "a bright nebulosity, 2' in diameter, without a tail, and with a well-defined stellar nucleus, the light of which is comparable with that of a star of the eighth or ninth magnitude." Denning's comet was seen on March 19 and 20, and five observations of position were made. It is described as "a feeble nebulosity without a tail, 25" to 30" in diameter, brighter towards the centre, but without any apparent nucleus. Its light was at the most equal to that of stars of magnitude 13." M. Rayet observed Swift's comet on March 17 and 19, and estimated that its nucleus was of the sixth or seventh magnitude.

M. Terby, in a letter to M. Faye, claims priority for the idea that solar spots and other disturbances on the sun exert an influence on terrestrial magnetism and electricity which varies according to the position of the phenomena with reference to the sun's visible disk. In a paper presented to the Brussels Academy in 1883, "On the Existence and Cause of a Monthly Periodicity of Aurora," he showed that the fluctuations in frequency of aurora were connected with the period of the sun's synodic rotation. Hence, some portions of the solar surface seem more capable of exerting terrestrial influence than others.

VARIABILITY OF NEBULE.-In NATURE of January 14 (p. 261) some observations were described which seemed to indicate that a nebula in R. A. 3h. 36m., Decl. 95' 2'1, was variable. Dr. Lewis Swift notes, in Astronomy and AstroPhysics, that he has again looked for the nebula, and on January 31 succeeded in getting two glimpses of it, using a power of 195. Although Dr. Swift is not inclined to believe that the nebula is variable, it is strange that he should at one time have picked up the object whilst sweeping, and yet not be able to find it afterwards, even with the most persistent searching. That Dr. Dreyer, also, should have failed to see the nebula on several occasions, although he knew where and what to look for, is almost unaccountable, if the brightness is uniform. It is to be regretted that the illumination of the sky at Rochester, from the electric lights, seems likely to prevent Dr. Swift from continuing his search for nebula.

SOLAR PROMINENCE PHOTOGRAPHY.-As the great spotgroup of February was again coming round the sun's east limb on March 3, M. Deslandres observed over it a prominence. He also photographed it, and, at the meeting of the Paris

Academy of March 14, communicated the results obtained. The Fraunhofer lines H and K are very bright on the photographs, and the entire series of ultra-violet hydrogen lines are plainly visible. Other lines are seen which have not previously been recognized as chromosphere lines, viz. the magnesium triplet about A 383, and lines at AA 375'93, 376'14, and 368*53, the origins of which are unknown.

THE AURORA SPECTRUM.-The aurora of February 13 was seen at Chicago, and Prof. Hale made some observations of its spectrum, using a small direct-vision spectroscope. A bright band was made out in the red, near C, and another was identified as the characteristic aurora-line. A very faint line, broad and hazy, appeared in the green, near the position of 6, and a faint one near F.

THE PROPERTIES OF AMORPHOUS BORON. THE properties of pure amorphous boron form the subject of a contribution to the current number of the Comptes rendus by M. Moissan. In our chemical note of March 3 (p. 421), the method was described by which M. Moissan has recently succeeded in preparing the amorphous form of boron in a state of almost perfect purity. The method consisted in reducing an excess of boric anhydride with powdered metallic magnesium, and subsequently repeatedly extracting the soluble products by acids. He now proceeds to describe the physical and chemical properties of the element as thus obtained. Pure amorphous boron is a fine chestnut-coloured powder, which may be readily moulded into adhesive masses by pressure. Its density is 2:45. It is infusible, even at the temperature of the electric arc. When heated in the air to a temperature in the neighbourhood of 700°, it inflames, and burns with formation of boric anhydride. If a small quantity is heated strongly in a test-tube, and, while hot, thrown into the air, a host of brilliant sparks are produced. When the powder is heated in a current of oxygen it burns with an intensely luminous flame, which, when the experiment is performed in a dark room, is observed to possess a green tint. The rays emitted are almost devoid of actinic power, the greater portion of the chemically active end of the spectrum being wanting. Pure amorphous boron reacts in a beautiful manner with sulphur at a temperature of about 610', brilliant incandescence occurring with production of sulphide of boron. This latter substance is decomposed by water with liberation of sulphuretted hydrogen. Selenium reacts with amorphous boron in an analogous manner at a higher temperature, but without incandescence, the selenide of boron produced evolving hydrogen selenide when brought in contact with water. Tellurium, however, may be fused in presence of boron without any reaction occurring.

When amorphous boron is heated in an atmosphere of chlorine to 410, combination accompanied by bright incandescence occurs with formation of chloride of boron, which, if the experiment is performed in a suitable apparatus, distils over into a receiver placed to intercept it. Bromine combines with boron to form the liquid bromide of boron at a temperature approaching 700°, the reaction likewise being accompanied by incandescence. Even bromine water attacks boron, although slowly, at the ordinary temperature, and an aqueous solution of bromine in potassium bromide attacks it rapidly. Iodine appears to be without action even at a red heat. Amorphous boron only combines directly with nitrogen at a high temperature, mere traces of the nitride being produced at temperatures below 900 when the powder is heated in a current of nitrogen; but at about 1200° combination rapidly occurs. The vapours of phosphorus, arsenic, and antimony do not react at available temperatures. When amorphous boron is heated in the electric arc in an atmosphere of hydrogen, boride of carbon is formed with a portion of the carbon of the poles.

The behaviour of metals towards amorphous boron is somewhat singular. The alkali metals may actually be distilled over the powder without any apparent trace of combination. Magnesium, on the contrary, combines with boron to form a boride at a low red heat. Iron and aluminium also form borides at a red heat, and silver and platinum react with even greater facility.

Acids react with amorphous boron with considerable energy. At 250 sulphuric acid is reduced to sulphur dioxide. Nitric acid in small quantities produces incandescence. Phosphoric anhydride is reduced at 800 to phosphorus. Arsenious and

arsenic acids are reduced at low redness with sublimation of annuli of arsenic. When the powder is dropped into a warm solution of iodic acid, iodine is liberated, and if a mixture of amorphous boron and crystallized iodic acid is slightly warmed, it takes fire, and a cloud of iodine vapour is produced. Gaseous hydrofluoric acid attacks amorphous boron at low redness, hydrogen being liberated, and fluoride of boron produced. Hydrochloric acid only reacts at bright redness.

Steam does not react with boron below a red heat, but the moment incandescence commences at any point the decomposition proceeds with explosive violence, hydrogen being liberated and boric anhydride produced. Carbon monoxide is reduced by boron at 1200°, with formation of boric anhydride and deposition of carbon. When amorphous boron is heated to low redness in a current of nitrous oxide, incandescence is produced, and boron nitride and boric anhydride are formed. Nitric oxide, however, does not react with boron under these circumstances.

Metallic oxides are much more readily reduced by boron than by carbon. For instance, when a mixture of copper oxide and amorphous boron is heated in a glass test-tube, the heat produced in the act of reduction is so great that the glass immediately fuses. Oxides of tin, lead, antimony, and bismuth are immediately reduced upon slightly warming, and the mass becomes white hot. When peroxide of lead is rubbed in a mortar with amorphous boron, a violent detonation occurs. Oxides of iron and cobalt are reduced at a red heat, but the alkaline earths are not attacked by boron. When caustic potash is fused in contact with amorphous boron, a vigorous reaction occurs, with rapid evolution of hydrogen.

The great affinity of boron for oxygen may be readily shown by making a gunpowder in which carbon is replaced by boron; if such a mixture of amorphous boron, sulphur, and nitre is made, it will be found to explode considerably below the lowest red heat. If a few particles of amorphous boron are allowed to fall into fused potassium chlorate, quite a pyrotechnic display is produced. The behaviour of certain fluorides towards amorphous boron is interesting. Silver fluoride, for instance, reacts in the cold upon simple contact in a mortar, with incandescence and detonation. Many other fluorides are similarly decomposed on warming.

Sulphates of potassium and sodium are reduced to sulphides at a low red heat by amorphous boron with great energy, the mass becoming white hot. Fused nitre, however, only reacts at the temperature at which oxygen commences to be evolved, but fused nitrites of the alkali metals react with violence, and production of light and heat. Sodium carbonate, moreover, is reduced at the temperature of low redness with vivid incandescence. The reducing capabilities of boron appear to be even manifested in presence of water, for the powder rapidly decolorizes a solution of permanganate, and reduces solutions of ferric salts to ferrous. Silver nitrate in solution is reduced with deposition of crystals of metallic silver; gold chloride also yields an immediate precipitate of finely divided gold, and platinum chloride is likewise reduced with precipitation of platinum upon warning. A. E. TUTTON.

THE MANCHU RACE.

THE origin of the Manchus the race to which the reigning dynasty in China belongs-is discussed by a writer in the North China Herald, of Shanghai. He says that the Tungus people are scattered about in Siberia and Manchuria in rather small communities of several hundreds or thousands each. In 1854 there were about thirty-five or forty thousand persons altogether in Siberia belonging to this race. Being hunters and fishers they find it best to live on the banks of rivers and on the seaside for fishing, and in wooded hill countries for hunting. They are met with, consequently, on the shores of the Baikal, and on the upper waters of the Lena, which rises among the

mountains west of that inland sea. These few colonies of this race are under the jurisdiction of Irkutsk. Still farther west there are a tribe or two on the Yenissei. Those on the Lena are near the part where the mammoth and other wild animals formerly had their haunts. The frozen remains of these ancient creatures are found chiefly at the mouth of the Lena, which flows north to the Arctic Sea through about twenty degrees of latitude from the neighbourhood of Baikal. On the east of the Baikal, Nerchinsk and the banks of the Orchon and Onon Rivers are preferred by this people, who are irregularly scattered,

among the Buriat tribes in this part of Siberia. In the Amur territory of Russia they occupy parts of the sea coast, and are known as the Orotches and Goldi. It is because the salmon and other fish that they live on are found in abundance that they here build their movable huts. In the Russian Amur province there are about forty thousand of them, representing an ancient race which, as their language, joined with the facts of Chinese history, shows, must have occupied these same territories and prosecuted these occupations for thousands of years. In Kirin province there are, it is likely, a corresponding number, for the trade with China always demands sable skins, otter skins, squirrel skins, beavers, ermines, and fox skins in an everincreasing quantity. It is this demand for skins that maintains the tribes in the north part of Kirin province residing on the banks of the Usuri and other streams which flow north into the Amur.

The Tungus tribes to which the Manchus belong first appear in history in the Chow dynasty. They are the Sokdin or Sushen of that age, and they were powerful in the eleventh century before our era. They are mentioned in the preface of the Book of History, so that we have next to classical authority for their existence at that distant period as a powerful state. The historian Tso mentions them in the sixth century, and from the way in which he speaks they were the strongest race in Tartary at the time. But in the third century, after nine hundred years of honour, their star went down, and the age of Turkish ascendency arrived. The Hiung-nu Turks of the Han dynasty had emperors of their own, who at least on one occasion were received in China on terms of equality with the haughty sovereigns of their southern neighbours. They could call themselves eldest sons of heaven and brothers of the sun and moon, just as the Chinse could, and therefore they did so. But their star also went down. The Turkish race has been used to rule wild tribes for 2000 years. We know that the Hiung-nu were Turks by the words left of their vocabulary which are found recorded in Chinese history. But their power declined, and then the Sushen, or Tungus, rose again to influence, and it was because they lived in the eastern provinces, where the valleys are rich in productive power, and because they had the good sense to profit by Chinese teaching. When China conquered the Moukden province and Corea, a century before the Christian era, the result was that the habits of life of the Chinese and their moral and intellectual activity spread to the east and north-east. Tungus and Corean tribes came under this new influence, and grew more powerful in proportion to the progress they made in the adoption of a civilized life. The Tungus Ambassadors arrived at Loyang in A. D. 263 and 291; and a few years later, when the Tsin Emperor had removed his Court to Nanking, they appeared there. Probably they came from the mouth of the Newchwang River by sea, for we know that the Chinese junk-masters navigated the Gulf of Pechili fully 2000 years ago. The troops which subjugated Corea at that time were there in large junks. Meanwhile other branches of the Tungus race had become sufficiently powerful to disturb the quiet of North China. Among them were the Owan and Sien Pi. The Sien Pi and the Hiung-nu conquered large portions of Chinese territory. The Tungus people ruled in the province of Peking. The Turks occupied Shansi, and Tibetan tribes took possession of Shensi. Each of these races seized on that part of North China which lay contiguous to their homes in Tartary. This state of things lasted till the latter part of the fifth century, when the Chinese drove the Tartars out. Again, however, at the beginning of the twelfth century a Tungus race conquered North China, and was followed later by a Mongolian dynasty, to which the Chinese of north and south all submitted for a hundred years.

The Mongols as a race are probably an offshoot from Tungus stock. There are differences, but there is on the whole a great resemblance. The consanguinity that exists between Manchu and Mongol is greater than that which is found to prevail between Mongol and Turk; and therefore it may be concluded that the Tungus, either in Siberia or in Manchuria or on the Amur, threw off a branch which became Mongol. This would be of a very ancient date,ifor otherwise the grammars of the Mongol and Manchu would be more alike than they are. Genghis Khan and his tribe started on the conquest of the Asiatic continent from the neighbourhood of the gold mines in Nerchinsk, and the Mongols are not fishermen by preference nor hunters of the sable martin and the beaver. They are rather keepers of sheep and riders of horses and camels. They

might easily develop their language in the vicinity of the Altai Mountains and the Baikal.

As to the Manchus, they have forgotten their early occupa tions since coming to China, and they attend now only to the duties of the public service or to military training. The language, like the Mongol, is rich with the spoils of antiquity. All the various forms of culture, whether belonging to Shamanism, Confucianism, or Buddhism, with which they have become successively familiar, have contributed a share. Το these must be added the vocabulary of the huntsman, the fisherman, and the shepherd, and all the terms necessary for the feudal relationship as well as those of the trades and occupations of the old civilization.

SOCIETIES AND ACADEMIES.
LONDON.

Physical Society, March 11.-Prof. A. W. Rücker, F.R. S., Vice-President, in the chair.-Mr. H. M. Elder read a paper on a thermodynamical view of the action of light on silver chloride. In the decomposition of silver chloride by light, chlorine is given off, and a coloured solid body of unknown composition (sometimes called "photochloride") formed, the reaction being indicated by the formula #AgCl = Ag„Clπ-1+¿Cl2. If the experiment be carried out in a sealed vacuum, the chloride is darkened up to a certain point, but regains whiteness when left in the dark. These facts have led the author to believe that the pressure of the liberated chlorine is a function of the illumination or intensity of light falling upon the chloride, in the same way as the pressure of a saturated vapour is a function of the temperature. Since illumination is a quantity in many respects analogous to temperature, he considers it not unreasonable to apply thermodynamic arguments, and regard chlorine in presence of silver chloride and "photochloride" as the working substance in a light engine." He therefore supposes a Carnot's cycle to be performed on the substances at constant temperature, the variables being pressure, volume, and illumination. Since the cycle is strictly analogous to Carnot's, except that illumination is written for temperature, he infers that the efficiency is a function of the two illuminations. It also follows

that just as Carnot's cycle is used to determine an absolute scale of temperature, so this cycle may be applied to determine an absolute scale of illumination. It only remains to determine an empiric scale analogous to the air therinometer, and to compare it with the photodynamic scale, provided a method of inaking the comparison can be devised. Assuming the axioms applied to Carnot's cycle are true when illumination is written for temperature, the author shows mathematically that poc IP/T, where is the pressure, I the illumination, T the absolute temperature, and p the heat of combination per gramme-molecule of chlorine evolved. If P be the heat of formation of silver chloride, the fraction p/P may be considered as expressing the fraction of the total chlorine that can be removed by the action of light upon it, supposing the gas removed so as to keep the pressure below that corresponding to the illumination. chemical equation might then be written

P/pAgCl = Agp Clpp-1+ Cl2;

The

thus the formula for "photochloride" would be AgpCpp-1. Prof. Rücker read a letter from the President (Prof. Fitzgerald) on the subject of the paper. He inquired what axiom corresponding with the second law of thermodynamics was employed. He was not sure that the engine was perfectly rever. sible, and felt doubt on the subject of phosphorescence mentioned in the last operation of the cycle. Nevertheless, the paper was a most interesting one, and very suggestive. Prof. Herschel pointed out that Becquerel's phosphoroscope showed that all kinds of light produced phosphorescence, and thought that, in considering the subject, the non-thermal character of photogenic light should' be kept in view. Mr. Baker said he had been working on silver chloride for several years, and found that no darkening whatever took place if kept dry and in vacuo. He considered oxygen necessary to the action. Dr. C. V. Burton, referring to the moivity of the system, said that only a small fraction of the energy of the illumination was actually made use of. He also thought it necessary to consider how far the second law of thermodynamics could be treated as an axiom. He himself had been led to be- |

lieve the law did not hold for mixtures of substances differing in a finite degree from one another. Some time ago he experimented on a solution of sodium sulphate placed in a dialyzer kept at constant temperature. The more acid portion pas ed through the membrane, and on mixing a rise of tempera. ture was observed; the dialyzer thus acted like Maxwell's demons, and the mixing increased the motivity of the system. Prof. Rücker expressed his doubts as to whether the cycle described in the paper was strictly analogous to that in Carnot's problem. In the latter case the parts of the working substance only differed infinitesimally from one another, whilst in the former the working body was a mixture of two solids and a gas. In order that the increa-ed illumination should not alter the temperature, heat must be carried away. According to the paper, the first part of the cycle must be both adiabatic and isothermal. This seemed hardly possible. If the chlorine alone be considered, it could not be true, and it could only hold if the chloride absorbed all the heat given out by the compression of the chlorine. This seemed improbable, but, if true, it would be very important. Captain Abney saw another difficulty in the fact that at low temperatures silver chloride is not acted on even by violet light, whereas heating greatly increases the action. In his opinion the conclusions arrived at required confirmation, but the paper would form a starting-point for many new experiments. Mr. Elder, in reply to Prof. Fitzgerald, said the axiom corresponding to the second law as stated by Clausius might be formulated thus: Energy cannot of itself pass from a less bright to a brighter body. In the paper he had assumed that the energy given out during compression at the lower illumination was of the same quality as that absorbed at the higher. The whole question depended on comparisons of intensities of illuminations of different wave-lengths. In the expression IPT, p was probably a function of T, and Captain Abney's objection was not necessarily fatal. Speaking of the presence of oxygen being essential to decomposition, he believed some sensitizing body was necessary, but judging from experiments he had seen, an infinitesimal quantity would probably be sufficient, for the action seemed to be of a catalytic He felt the weight of Prof. Rücker's objections, but thought they might possibly be met.-A paper on choking Regarding a choking coils was read by Prof. Perry, F.R.S.

nature.

coil as a transformer with one primary and many secondaries represented by the conducting ma-ses, he pointed out that all the secondaries might be replaced by a single coil of n turns, and resistance ohms, short-circuited on its If. Assuming no magnetic leakage, the equations for the two circuits at any instant are V = RC NOI, and O = re+nel, where N and # are the turns, R and the resistances, I the total induction in 10 C.G. S. lines), and C and c the primary and secondary currents respectively. Since the exciting current, C, is all-important in choking coils, and its value depending on the law of magnetization, the equations are treated in a different manner from that adopted in ordinary transformer calculations. Expressing the magnetic law as a Fourier series, I = Σ A,σ; sin ix, the value of A (viz. NC + nc) is deduced, and when V or I is given as a periodic function of the time, C may be calculated. Assuming V = V sin kt, the author finds

、'1 + 2e sin ƒ+e2, sin { kt −90+tan‍ tanƒ+

=

cus f

where e = nakir, f is the hysteresis term, and and m constants depending on the law of magnetization. For ordinary transformer magnetizations, b 0'2, and m = 005. From the above expression it will be seen that if there is no hysteresis (i.e. fo), the effect of the eddy currents, e, is to increase the amplitude of the important term, and to produce a lead of 90° cot-le, whereas the effect of hysteresis without eddy currents is to leave the amplitude unaltered, and produce a lead f. Putting = o gives results in accordance with experimental observation, hence the author is inclined to believe that there is no hysteresis in transformers. He also points out that the higher harmonics must exist, and thinks it probably that a choking coil with finely divided iron may prove a method of increasing frequency by mere magnetic means. Taking the case of a 1500-watt transformer (2000 volts) unloaded, in which the loss in eddies was 40 watts, it is shown that a secondary of 2 turns, and resistance 19 ohms, would replace the eddy

current circuits. Assuming constant permeability and no eddy currents. the value of C comes out o 07398 sin (kt - 90°), whilst with eddy currents and some saturation

C=0 07911sin(k! − 69°·2) — 0 ̊014796 cos 3 kt -0.003695 cos 5kt. Dr. Fleming said he was working on the subject of choking coils, and had found that, in closed-circuit transformers unloaded, the real watts were about 07 times the apparent watts. This, on the assumption of sine functions, would indicate a lag of about 45%.

A similar rule for open circuit transformers was much needed. It was important to know what size of core and coil was required to choke down to a given current. Dr. Sumpner thought it better to treat the subject graphically rather than by analisis, and described a construction whereby the fundamental equations could be readily integrated. Prof. Perry said he had reason to think that ordinary hysteresis curves were not applic. able to transformers. By analysis of the experimental E. M.F. and current curves, one could work backwards and find the true hysteresis curves.

Chemical Society, March 3.-Prof. A. Crum Brown, F.R.S., in the chair.-An address was read, which it is proposed to present to Prof. Bunsen, who has now been for fifty years a foreign member of the Society.-The following papers were then read :-A rule for determining whether a given benzene mono-derivative shall give a meta-di-derivative or a mixture of ortho- and para-di-derivatives, by Prof. A. Crum Brown and Dr. Gibson. If a benzene mono-derivative be converted into a di derivative by replacement of a second atom of hydrogen in the nucleus by a radicle of the same kind as the one already present, the product may consist either of the meta-di-derivative or a mixture of ortho- and para-di-derivatives. The authors suggest a rule for determining which of these two cases will result in any instance. If the hydride of the radicle employed is directly convertible into the corresponding hydroxide, the meta-di-derivative will be obtained on further substitution by the same radicle. If the hydride of the substituting radicle is not directly oxidizable to the hydroxy-compound a mixture of ortho- and para-di-derivatives will result. For example, when the substituting radicle is chlorine, as in the case of monochlorobenzene, hydrogen chloride not being directly oxidizable to hypochlorous acid, the rule indicates that a mixture of orthoand para di derivatives will be obtained on further chlorination. Nitrous acid is readily converted by direct oxidation into nitric acid, so that on nitration of nitrobenzene, meta-dinitrobenzene alone should be produced if the rule be a correct one. In these, as in the other cases cited by the authors, the rule is found to hold good. The relative orienting effect of chlorine and bromine; (1) The constitution of parabrom- and parachloranilinesulphonic acids, by H. E. Armstrong and J. F. Briggs. Parachlorobromobenzene on sulphonation yields one sulphonic acid, CH. Br. Cl. OH, possessing the constitution CI: SO,H: Br 12:4. = The authors were unable to obtain two sulphonic acids on sulphonating parachloraniline; only one was produced, which separates from its aqueous solution in three distinct forms. This also holds true for the sulphonation of parabromaniline, the sulphonic acids having the constitution Cl or Br: SO,H: NH, =1:2: 4-Note on anhydrides of sulphonic acids, by H. E. Armstrong. When para-dichloro-, chlorobromo-, and dibromobenzene are treated with sulphuric acid containing about 20 per cent. of sulphuric anhydride, sulphonic anhydrides are obtained. These compounds probably owe their formation to the dehydration of the corresponding sulphonic acids first formed.-Contributions to the knowledge of the aconite alkaloids; Part II. The alkaloids of true Aconitum napellus, by W R. Dunstan and J. C. Umney. The roots of true Aconitum napellus were extracted with cold fusel oil. The solution so obtained was, after some preliminary treatment, extracted with ether.

Two alkaloids were thus extracted, and were separated by means of their hydrobromides into a crystalline and a gummy alkaloid. The former of these was found to be aconitine, whilst the noncrystallizable compound is a new alkaloid which the authors term napelline. This alkaloid is soluble in e her and alcohol, and has a very bitter taste, but does not give rise to the tingling sensation so characteristic of aconitine. Its salts could not be crystallized. By further extraction of the fusel oil with chloroform, aconine was obtained. The roots of true Aconitum napelus, therefore, must be held to contain three alkaloids, one of which, viz. aconitine, is crystalline, whilst two are amorphous, viz. napelline and acontne. Indications have been obtained of the presence of a fourth alkaloid, which is amorphous and

closely resembles napelline. Aconitine is by far the most toxic of the alkaloids contained in Aconitum napellus.-Contributions to our knowledge of the aconite alkaloids; Part III. The formation and properties of aconine and its conversion into aconitine, by W. R. Dunstan and F. W. Passmore. When pure aconitine is hydrolyzed by heating it with water in closed tubes at 150°, aconine and benzoic acid are obtained in accordance with the following equation

41

no picraconitine or methyl alcohol is obtained at any stage. Anhydro-aconitine is formed by the interaction of aconine and ethyl benzoate at 130°, leaving no doubt that aconitine is benzoyl-aconine. Aconine yields a crystalline hydrochloride, C26H1NO11, HCl, 2H,O, whose specific rotatory power [a] -7071. Pure aconine is a hygroscopic, brittle gum, having the composition C6H4NO11, and the rotatory power [a]D = + 23. Its solution reduces Fehling's solution and gold and silver salts. Its aqueous solution is slightly bitter, and A crystalline gives rise to a burning sensation in the mouth. methydroxide, CH45 NO12,CH,. OH, have been prepared. aconitine methiodide, C3345NO12,CH,I, and an amorphous A simple laboratory shaking appliance, devised by Prof. Dunstan and Mr. Dymond, was exhibited at the conclusion of this paper.-Note on the carbon deposited from coal gas flames, by W. Foster. The author quotes analyses of cokes obtained by carbonizing sugar and starch. From the similarity in composition of these cokes to that of the soot obtainable from coal-gas flames, he is of opinion that these substances are all formed by somewhat similar chemical processes.-The volumetric estimation of mercury, by Chapman Jones. The author has devised a modification of the cyanide method of estimating mercury.— Chromic acid, by Eleanor Field. Results are quoted showing that the crystals obtained on cooling with ice a solution of chromium trioxide saturated at 90° consist merely of the trioxide, CrO3, and not of chromic acid, HCrO4, as stated by Moissan. -The origin of acetylene in flames, by V. B. Lewes. The author has sought to determine whether acetylene is the product of high temperature change or of oxidation. The experiments described consisted in passing hydrocarbon gases and mixtures of such gases with others through a heated platinum tube. The results obtained appear to point to acetylene being formed by the action of heat alone.

Geological Society, March 9.-W. H. Hudleston, F. R.S., President, in the chair.-The following communications were read-The new railway from Grays Thurrock to Romford : sections between Upminster and Romford, by T. V. Holmes. In the Hornchurch cutting of the new railway, boulder clay, of which about 15 feet is seen, rests upon the London Clay near the 100-feet contour-line, and is overlain by 10 to 12 feet of sand and gravel. The author gives reasons for inferring that this sand and gravel belongs to the oldest terrace of the Thames Valley gravel occurring in this district, and states that it demonstrates the truth of Mr. Whitaker's conclusion that the Thames Valley deposits are (1 cally) post-Glacial, or newer than the local boulder clay. After the reading of this paper the President said that geologists were much indebted to Mr. Holmes for drawing attention to this interesting section before it was too late. Amongst the many points arising from the discovery of boulder clay at less than 100 feet above Ordnance datum was one as to the probability of the pre- Glacial age of the Thames Valley system. Mr. H. B. Woodward, Mr. H. W. Monckton, Mr. C. Reid, Dr. Hicks, Mr. Lewis Abbott, and Mr. Whitaker also spoke.-The drift beds of the North Wales and Mid-Wales coast, by T. Mellard Reade. This paper is a continuation of papers by the author on the drift beds of the north-west of England and North Wales. The author first treats of the Moel Tryfaen and other Caernarvonshire drifts; he describes the drifts of the coast and coastal plain, connecting his observations with those of the Moel Tryfaen drifts. An important feature of the investigation is the numerous mechanical analyses of the various clays, sands, and gravels. In all the samples but one, a large proportion of extremely rounded and polished quartz-grains have been found, which the author maintains to be true erratics, and a certain sign of marine action. He shows that the Moel Tryfaen marine sands are in part overlain by typical till, composed almost wholly of local rocks with a small percentage of clay, whereas the sands and gravels are full of erratics, including rocks from Scotland and the Lake District, numerous flints, Carboniferous Limestone, and