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the elements still show very considerable divergences, the re- useful work. Prof. Korzynski has explored the Amur region, searches conducted by Prof. H. F. Weber on boron, silex, and with especial reference to the advantages it offers for culture and carbon, regarding the dependence of the specific heats upon the colonization : V. A. Obrutcheff continued the exploration of the temperature, are to be extended to several other elements, Olekma and Vitim highlands ; MM. Yadrintseff, Klementz, and prepared as pure as possible, and also to combinations or alloys Levin took part in Prof. Radloff's expedition to the valley of of them. Further, the densities and the thermic coefficients the Orkhon in Mongolia ; and Dr. Kiriloff continued his studies of expansion of the substances investigated are to be ascertained of Mongolian medicine. The Museum at Irkutsk has been enas carefully as possible.” The following are the conditions : larged, and further enriched by new collections. The publicathe treatises handed in by competitors may be in German, tions of the Society included : the work of the Novaya Zemlya French, or English, and must be sent in by September 30, 1894. Polar Station ; the ornithology of North-west Mongolia, by MM. The examination of the treatises will be intrusted to a Committee Berezovsky and Bianchi ; several volumes of Memoirs ; and the consisting of the following gentlemen : Prof. Pernet, Zürich; Bulletin (Izvestia). The new monthly periodical, meteorological Prof. A. Hantzsch, Zürich; Prof. E. Dorn, Halle-on-the. Vyestnik, and the “ Living Antiquity" (Jivaya Starina) have Saale ; Prof. J. Wislicenus, Leipzig ; Prof. E. Schär, Zürich, been issued regularly during the past year. as member of the Committee offering the prizes. The Prize Committee is empowered to award a first prize of two thousand

We are glad to be able to report an advance in the Meteoro. francs, and minor prizes at its discretion to the amount of one logical Service of Roumania. For some years the official thousand francs. The work to which the first prize is awarded publication of that country has been limited to the yearly

From is to be the property of Schnyder von Wartensee's Foundation, volume containing the observations for Bucharest. and arrangements will be made with the author regarding its January i last, however, the Meteorological Institute has begun publication. Every treatise sent in must have a motto on the

the issue of a monthly bulletin containing observations taken title-page, and be accompanied with a sealed envelope bearing three times daily at Soulina, Bucharest, and Sinaia, 6 feet, 269 the same motto outside and containing the author's name. The

feet, and 2821 feet above the sea, respectively. The various treatises are to be sent to the following address : “An das weather phenomena are represented by the symbols adopted for Praesidium des Conventes der Stadtbibliothek, Zürich (betreffend international meteorological publications. Preisaufgabe der Stiftung von Schnyder von Wartensee für das The Danish Meteorological Institute and the Deutsche See. Jahr 1894).”

warte, conjointly, have recently issued daily synoptic weather At the meeting, on February 17, of the Russian Geographical charts, for the North Atlantic Ocean and adjacent continents, Society, the Constantine Medal was awarded to M. V. Pyevtsoff for the year ending November 1887, completing the series from for his work of exploration in Central Asia, especially during September 1873, with the exception of the following dates : the last Tibet expedition. The Count Lütke Medal was December 1876 to November 1880, being the period which awarded to A. I. Vilkitsky for his measurements of pendulum elapsed from the death of Captain N. Hoffmeyer, who comoscillations in Russia. A newly established prize, consist- menced the work, to its resumption by the two above-named ing of the interest on a sum collected by public subscription institutions; and September 1882 to August 1883, being the after the death of Prjevalsky, was granted to G. E. Grum- | period for which the Meteorological Office published its elaborate Grzimailo for his researches in Central Asia in 1889-90, and synchronous charts for the same area. For three years ending large silver medals, also associated with Prjevalsky's name, November 1886, the Deutsche Seewarte has published a separate were awarded to the companions of his expeditions, V. I. text explanatory of the general conditions of weather for the area Soborovsky and P. K. Kozloff, to the geologist of the embraced by the charts, and showing the effect of the conditions last Tibet expedition, K. I. Bogdanovitch, for his geological upon the navigation of vessels, together with charts, selected work in Central Asia, and to M. E. Grum-Grzimailo for the for various periods of special interest, showing the position and surveys he made in company with his brother in the Pamir. The movements of barometrical maxima and minima. The work great Gold Medal of the Sociely was awarded by the Section of furnishes the best possible materials for studying the connection Ethnography to A. N. Pypin, for his “ History of Russian between the weather of the Atlantic and that of our islands. Ethnography,” and by the Section of Statistics to A. A. Observations of air-pressure during a total solar eclipse Kaufmann for his researches on the economical conditions of reveal an influence of the latter phenomenon on the former. the peasants and indigenes in the Ishim and Tura districts of In a recent number of the Annalen der Hydrographie, Herr West Siberia. Four small gold medals and seventeen silver

Steen studies the eclipse of August 29, 1886, in this respect, ones were awarded for works of less importance.

using the records (at intervals of a quarter of an hour) of fourAt the same meeting the yearly report of the Society was teen Norwegian ships between Panama and Madagascar, of read, and we learn from it that the Expedition which has been which four were in the zone of totality, and at least four others sent out for the exploration of the Chinese province Sy.chuang, quite close to it. Having first eliminated the daily period of and the territory on the slopes of the Tibet plateau, will soon air-pressure, he groups the observations of the ships, and forms start from Peking. The leader of the Expedition, the zoologist means; and he finds bɔth these and the individual records M. V. Berezovsky, is already in Peking, preparing to start on reveal two maxima of air-pressure, separated by a minimum. In his journey. N. F. Katanoff is hard at work collecting ethno- the totality zone the first maximum is 35m., and the second graphical materials in Mongolia. K. P. Sternberg continued 2h. 15m., aster the middle of the eclipse ; in the partial zone, his pendulum observations in South Russia and Crimea ; and the first is 25m. before, and the second ih. 40m., aster, the A. E. Radd continued to investigate the magnetic anomalies middle. This double wave, Herr Steen explains thus. During about Byelgorod, in Kursk. L. I. Lutughin has made geo- a solar eclipse, day is changed to night for a short time, and logical explorations and levellings on the watershed between the the transition is much like the ordinary change fron day to Volga and the Northern Dvina ; while the Ministry of the Navy night in the tropics, where the twilight is but short. There the has continued this year the exploration of the Black Sea. In curve of air-pressure has regularly a maximum about 10 p.m., the department of ethnography, the report mentions the work some time after sunset, and a minimum about 4 a. m., shortly of E. R. Romanoff in White Russia, and MM. G. E. Veres. before sunrise ; while a second maximum appears about 10 a.m. chaghin and Shilkoff among the Votyaks. The East Siberian It is natural a total solar eclipse should act similarly. The disbranch of the Society has accomplished, as usual, a good deal of placement of the "epochs” of the air-pressure wave in the partial


pone as compared with the zone of totality is more difficult to publication, to be called British Museum Phycological Memoirs, account for.

edited by Mr. George Murray. It will be devoted exclusively THE Smithsonian Institution has printed a capital study of

to original algological papers, the records of research carried on the puma or American lion (Felis concolor of Linnæus), by Mr.

in the Cryptogamic laboratory of the British Museum in Cromwell F. W. True. The author notes that the puma possesses in a

Road, and is intended to be issued at about half-yearly intervals remarkable degree the power of adapting himself to varied sur

The first part will be illustrated by eight plates, and will contain, roundings. The animal endures severe cold during the winter in

among other articles, the description of a new order of Marine the Adirondack Mountains and other parts of the northern frontier | Algæ. of the United States, and tracks his prey in the snow. He is DR. Baillon's "Dictionnaire de Botanique," the publication equally at home in the hot swamps and canebrakes along the of which was commenced in 1869, is now completed. river-courses of the Southern States. In South America he inhabits the treeless, grass-covered pampas as well as the forests.

A New acid, chromosulphuric, possessing the composition In the Rocky Mountains, as Mr. True is informed by Mr.

H,Cr,(S0.)4, is described by M. Recoura in the current numbe. William T. Hornaday, he ascends to the high altitudes in which

of the Comptes rendus. A short time ago the same chemist

obtained a remarkable isomeric form of chronic sulphate, the mountain sheep are found. Mr. Livingston Stone saw tracks of the puma on the summit of Mount Persephone in California, Cr,(SO4)3, which exhibited neither the reactions of a sulphate at an elevation of 3000 feet. Similarly, Darwin states that he

nor of a salt of chromium. For instance, its solution yielded saw the footprints of the puma on the Cordillera of Central Chili

, isomeric form of chromic sulphate is found to combine directly

no precipitate of barium sulphate with barium chloride. This at an elevation of at least 10,000 feet. According to Tschudi, the puma is found in Peru in the highest forests and even to

with one equivalent of sulphuric acid or of a metallic sulphate to the snow-line.

produce the new acid, or a salt of it. Thus, when a solution

of zinc sulphate is mixed with a solution of the isomeric sulphate In his Report on the Royal Botanic Gardens, Trinidad, for of chromium in equivalent molecular proportion, zinc chromo1890, just issued, Mr. J. H. Hart, the Superintendent, says sulphate is formed, ZnCry(S0.4. The solution of this zinc salt that, while on a journey to St. Vincent, in August 1890, he so obtained gives none of the reactions of sulphuric acid, nor discovered a form of Agave rigida, Mill., previously unknown does it yield those of chromic acid, but it exhibits the usual to West Indian floras. It produces a useful fibre, but appears reactions of zinc salts; hence it must be a zinc salt of a specific to be too short in the leaf to rival the variety known as Agave acid, chromosulphuric. When the solutions of the new acid and rigida, var. sisalana, of Perrine. The same species has also its salts are allowed to stand, they gradually decompose, and since been found in Barbados, and identified with the above. barium chloride commences to precipitate barium sulphate, hence “With nothing,” says Mr. Hart, “ is it more easy to make a they appear not to be very stable, but to decompose slowly into a mistake than the various species of Agave, and special care mixture of ordinary chromic sulphate and sulphuric acid or the should be taken by growers for economical purposes to have metallic sulpbate. Boiling brings about the decomposition at their plant identified by competent persons, before expending The acid itself has been obtained in the solid state, large sums on cultivation. As an instance, I may mention that combined with eleven molecules of water ; it is a green powder, the Coratoe of Jamaica was for long years popularly supposed which is very hygroscopic, and rapidly deliquesces in moist air to be no other than the Tropical American Agave americana, but is quite permanent in a dry atmosphere. Its solution posuntil an examination was made into its characteristics by Mr. sesses a brilliant green colour when freshly prepared, but, upon D. Morris when that gentleman was resident in Jamaica. The standing, changes to blue, and, after a few days, passes comsame thing occurred in Trinidad. The Langue Bauf of the pletely into a violet-coloured solution of ordinary chromic sulBocas Islands was for many years supposed to be Agave vivipara, phate mixed with free sulphuric acid. The potassium salt has Linn., but a plant sent to Kew from these Gardens proves it to also been obtained in the solid state, combined with four molebe the Mexican Agave polyacantha, Haw. A plant from St. cules of water, as a green powder whose dilute solution yields Lucia, recently received, shows characteristic points differing no precipitate with barium chloride, but at once gives the usual from any of the above, though popularly supposed to be iden- potassium precipitates with platinic chloride and picric acid. tical with our Bocas Island plant, and it may be found that This salt also appears to be formed when chrome alum is deseveral unknown Agaves exist in the West Indies that have been hydrated first for some time at 90°, and finally at 110°. The passed over by botanists from their similarity of growth to the sodium and ammonium salts have likewise been obtained, and commonly known forms of the larger islands and mainland." are found to resemble the potassium salt closely in their nature An excellent series of “Museum Hand-books” is being

and properties. issued by the Manchester Museum, Owens College. A The additions to the Zoological Society's Gardens during the “General Guide to the Contents of the Museum " has been past week include two Silver-backed Foxes (Canis chama), two prepared by Mr. W. E. Hoyle, Keeper of the Museum, and Leopard Tortoises (Testudo pardalis) from South Africa, preProf. Milnes Marshall has drawn up an “Outline Classification sented by Mr. C. Holmes; a Vulpine Phalanger (Phalangista of the Animal Kingdom," and a "Descriptive Catalogue of the vulpina 8 ) from Australia, presented by Mr. W. J. C. P. Macey; Embryological Models.”

a Ring-tailed Coati (Nasua rufa) from South America, preWe have received the tenth Annual Report of the U.S.

sented by Miss M. Tew; a Fallow Deer (Dama vulgaris ! ), Geological Survey to the Secretary of the Interior, 1888-89, by British, presented by Mrs. Edith Hilder ; a Milky Eagle Owl Mr. J. W. Powell, Director It is divided into two parts, the

(Bubo lacteus) from Mashonaland, South Africa, presented by first relating to geology, the second to irrigation.

Mr. E. A. Maund ; sour Herring Gulls (Larus argentatus), a

Lesser Black-backed Gull (Larus fuscus), two Black-headed MESSRS. GAUTHIER-VILLARS have published a work en

Gulls (Larus ridibundus), a Jackdaw (Corvus monedula), a titled “Leçons de Chimie,” by Henri Gautier and Georges Tawny Owl (Syrnium aluco), British, an Orange-cheeked MaxCharpy. It is intended mainly for the use of students of

bill (Estrelda melpoda) from South Africa, two Hooded Finches special mathematics.

(Spermestes cucullata) from West Africa, an Indian Silver-bill We learn from the Journal of Botany that the first part will (Munia malabarica) from India, twelve Barbary Turtle Doves shortly be issued by Messrs. Dulau and Co. of a new botanical Turtur risorius) from North Africa, presented by Mrs. Kate

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Taylor; a Sharp-nosed Crocodile (Crocodilus acutus) from The centre of gravity of Algol, and the distant unknown comHavana, presented by Mr. Arthur Morris ; a Chimpanzee panion, and the uniform proper motion of the latter being (Anthropopithecus troglodytes 8) from West Africa, a Bison

- O'odios. and + oʻ':01 20 annually, in the two co-ordinates (Bison americanus 8) from North America, an Anaconda

respectively. The annual parallax of the star is about o":07.

The mean period of light variation is 2d. 20h. 48m. 56'oos.” It (Eunectes murinus) from South America, deposited ; a Brazi- seems very probable, from Dr. Chandler's communication, that lian Tapir (Tapirus americanus ) from South America, four the inequalities in the periods of other variables of the Algol Hairy-rumped Agoutis (Dasyprocta prymnolopha) from Guiana, type will admit of a similar explanation. a Mexican Agouti (Dasyprocta mexicana) from Mexico, four THE SUN.SPOTS OF FEBRUARY.-Some facts with regard to Scarlet Ibises (Eudocimus ruber) from Para, a Blue and Black

the dimensions of the recent sun-spots appear in the March Tanager (Tanagrella cyanomelæna) from South-East Brazil, a

number of the Observatory. The group of spots apparently

connected with the great magnetic disturbance of February Prince Albert's Curassow (Crar alberti !) from Columbia,

13-14, and the aurora which was visible at a large number of purchased.

places on the latter date, was first seen on the east limb of the sun on February 5. It passed the central meridian six days

later, and disappeared rourd the west limb on February 17. OUR ASTRONOMICAL COLUMN.

“The total spotted area measured on the photographs taken at CORDOVA OBSERVATORY.- A publication of some importance Greenwich on February 13, when the group reached its maxihas recently been issued from the Observatorio Nacional Argen- mum, was no less than 1/350 of the sun's visible hemisphere. tino. It contains the observations made under the direction of At Greenwich the area of spots is measured in millionths of the Dr. Gould, in 1880, for the General Catalogue, arranged and sun's visible hemisphere, and this extensive group had an area published by Mr. J. M. Thome, the present Director of the of 2850 millionths, corresponding to 3360 millions of square Observatory. The mean places of 10,923 stars have been found miles. The centre of the group was then at 260° long., and in from 33,837 separate and complete determinations, and this lat. – 23°: The group was a broad band extending over 22° of during one year of observation. In addition, 1613 observations longitude in length and 10° of latitude in width, corresponding of circumpolars, and 1738 of time-stars, have been made for roughly to a greatest length of 150,000 miles and a width of determining instrumental corrections. It is therefore well re- 75,000 miles. The large central spot of the group was 15° in marked that “the dimensions of the volume almost entitle it length in longitude and 8° in width in latitude.

The spotto the rank of a General Catalogue, and the results for the group is the largest ever photographed at Greenwich, and is the month of December alone, when 5938 determinations of posi- largest which has appeared on the sun since 1873." tions were made, would form a fair Annual Catalogue." In

A New COMET. - Prof. Lewis Swift, of the Warner Observaorder to get through this immense amount of work, the meridian

tory, discovered a comet on March 6 in R.A. 18h. 59m., and circle was manned with an observer, a microscope reader, who N.P.D. 121° 20'. Unfortunately the comet is at present too far also pointed the telescope, and a recorder ; and on four nights south to be seen in these latitudes. of eight hours each, in December, these three observers made, on the average, 1549 complete determinations. And the work

PROF. KRUEGER (Astronomische Nachrichten, No. 3077) conhas been done in such a thorough manner, in spite of the rapidity tributes an important paper on the determination of the perof execution, that one cannot but admire the dexterity of Messrs.

turbations set up in the motions of periodic comets as they Bachmann, Davis, and Stevens, who have assisted Mr. Thome. approach the sun, owing to their proximity to the planets. The right ascensions are referred to the “Standard Places of Fundamental Stars,” second edition, published in 1866. The mean

PHOSPHOROUS OXIDE. places of these stars for the beginning of each year, to 1880 inclusive, are published in the American Ephemeris tables, and IN addition to the well-known pentoxide formed when phostheir apparent places in successive volumes. The magnitudes re.

phorus is burnt in air or oxygen, a second oxide of corded in the Catalogue are generally the results of estimation.

phosphorus has long been surmised to exist. Very little, howStars, however, which occur in the “Uranometria Argentina

ever, has hitherto been known concerning this second oxide. have had their magnitudes taken from the data collected for that

It is usually described in current chemical literature as a white work. Catalogues of southern stars are hardly so plentiful as

amorphous powder of the composition P,Oz, very voluminous, those containing places of stars north of the equator. This

somewhat more volatile and more readily fusible than the volume is therefore doubly welcome. It represents work carried

pentoxide P,Os, and instantly dissolved with great rise of out in spite of the vicissitudes to which an Observatory in the

iemperature by water, with formation of phosphorous acid. Argentine Republic must be subject, and the results obtained During the last three years an investigation has been carried out will be appreciated by all.

in the laboratory of the Royal College of Science by Prof.

Thorpe and the writer, which has resulted in showing that Algol.-In a series of contributions to the knowledge of the phosphorous oxide is a substance possessing properties entirely variable stars, which has appeared in the Astronomical Journal, different from these. Full details of this work have recently Dr. S. C. Chandler has discussed the periods, motions, and

been laid before the Chemical Society, but a short account of laws of variable stars. His last communication, contained in the manner in which the pure oxide has been isolated in Nos. 255 and 256 of the Journal, deals with the inequalities in quantiiy, of its somewhat remarkable properties, and of a few the period of B Persei ; the theory which satisfactorily accounts

of its more important reactions, may, perhaps, not be uninterestfor these and other phenomena being stated as follows :

ing to readers of NATURE. “Algol, together with the close companion—whose revolution in 2d. 20:8h. produces by eclipse the observed fluctuations in light,

Properties of Phosphorous Oxide. according to the well-known hypothesis of Goodriche, confirmed Before describing the mode of preparing the oxide, it will by the elegant investigation of Vogel—is subject to still another be advisable to briefly indicate the external appearance and orbital motion, of a quite different kind. Both have a common essential properties of the substance. Phosphorous oxide is not revolution about a third body, a large, distant, and dark com- an amorphous powder, but, at temperatures not exceeding 22° panion or primary, in a period of about 130 years. The size of C., a pure white crystalline solid, compact and beavy, soft and This orbit around the common centre of gravity is about equal to wax-like in character. Its most striking property is the ease that of Uranus around the sun. The plane of the orbit is with which it melts, the warmih of the hand which holds the inclined about 20° to our line of vision. Algol transited the vessel containing it being more than sufficient to convert it to plane passing through the centre of gravity perpendicular to the liquid state. Its melting point is 22°.5 C., hence upon a this line of vision in 1804 going outwards, and in 1869 coming warm summer's day or when placed in a warm room it takes inwards. Calling the first point the ascending node, the posi- the form of a clear, colourless liquid, very mobile, but sometion-angle, reckoned in the ordinary way, is about 65o. The what heavy. It is best preserved in sealed glass tubes, the orbit is sensibly circular, or of very moderate eccentricity. The air of which has been replaced before the introduction of the longest diameter of the projected ellipse, measured on the face of oxide by carbon dioxide or nitrogen in order to avoid the action the sky, is about 2".7. A necessary consequence of this theory of the oxygen contained in air, which rapidly converts is an irregularity of proper motion with an amplitude of some- phosphorous oxide to phosphoric oxide. When such a tube con. thing over a fifth of a time-second in right ascension, and nearly iaining the liquid oxide is cooled by immersing it in cold water one and a half seconds in declination ; the middle point being or allowing it to stand in a room of ordinary iemperature (17020° C.) the oxide rapidly resolidifies in a most beautiful manner, these volatile crystals in larger quantity, and of separating them large crystals shooting out in all directions until the whole is one entirely from the pentoxide, a method has at length been found compact mass of interlacing crystals. When the liquid is heated by which as much as twenty-eight grams of the pure oxide have in a distillation flask previously filled with one of the indifferent been obtained in an experiment of five hours' duration. gases carbon dioxide or nitrogen, it soon commences to boil, and Two sticks of phosphorus are cut into pieces about an inch the vapour condenses in the condensing tube and the unchanged and a half long, and placed in a glass tube bent into the shape oxide runs down into the receiver placed to intercept it in the shown at a in the figure, so as to retain the phosphorus when in form of liquid, which eventually condenses to the solid again. the melted condition. The tube should be of 11-inch bore, and Its boiling point is 173°1 C.

should be made from new soft glass tubing, which is quite hard The vapour of phosphorous oxide possesses a very character: enough to stand the heat of burning phosphorus. The tube is istic odour, which appears to be the same as that so noticeable drawn out somewhat, but quite open, at the end where the air is about a lucifer-match manufactory. Owing to its great volatility, to be admitted, and at the other is narrowed slightly, so as to both the solid and the liquid are constantly vapourizing, even at fit into the condenser b, a tight joint being obtained by means of the ordinary temperature, and hence the odour is always strongly a caoutchouc ring or a little bicycle cement. This condenser, b, marked in their neighbourhood.

is intended to retain the phosphorus pentoxide and any free Phosphorous oxide may also be obtained by spontaneous phosphorus produced during the combustion, and is maintained evaporation in vacuo in beautiful large isolated crystals, at such a temperature that the phosphorous oxide passes uncon. probably belonging to the monoclinic system, which are quite densed through it. It is therefore constructed of brass instead colourless and transparent, and very highly refractive; crystals of glass, and is made double, that is, with an outer jacket also have frequently been obtained in this manner an inch in length of brass, so that the space between the two brass tubes may be and broad and thick in proportion, showing numerous prism and filled with water of the required temperature.

This water may pyramid faces. Similar crystals are obtained when solutions of be run in by means of a funnel through a small vertical tube, d, the oxide in carbon bisulphide, chloroform, ether or benzene, a second such tube, e, serving for the introduction of a thermoin which the substance readily dissolves, are evaporated out of meter. The size of condenser found most convenient is 2 feet contact with the air.

in length, and the inner brass tube has a bore of 25 millimetres. Instead of reacting with violence with water, as appears to At the end of the condenser furthest from the phosphorus, a have been generally supposed, phosphorous oxide is plug of glass wool about half an inch long is inserted, the


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paratively indifferent to that liquid, only dissolving with great fibres being arranged transversely as much as possible ; such a slowness. If a few drops of the liquefied oxide are dropped plug forms an excellent means of filtering off any pentoxide into water of about the same temperature they at once fall to the which would otherwise escape into the phosphorous oxide conbottom of the tube, and the two liquids do not mix. If the denser, especially after the first few minutes of the combustion, water is at the ordinary temperature the oxide solidifies as it falls when its meshes become loosely filled with porous pentoxide. to the bottom. A few grams of the oxide, either liquid or solid, Directly into the end of the brass condenser fits tightly, by require several hours for complete solution. The solution con- means of a cork annulus, the large glass U-tube condenser, c, tains phosphorous acid. When phosphorous oxide is warmed in which the phosphorous oxide is condensed. The yield of with water to a temperature just below 100°, a violent reaction oxide appears to depend somewhat upon the shape and dimensions of an entirely different nature occurs; spontaneously inflammable of this condenser, that found most advantageous having the phosphoretted hydrogen is evolved with a loud explosion, and shape shown in the diagram, a height of 35 centimetres from red phosphorus and phosphoric acid are largely formed.

the bottom of the bend, and an internal bore of 14 millimetres.

A short vertical tube is fused on at the bend, and passes down Preparation of Phosphorous Oxide.

into a bottle, into which the oxide may be melted at the end of It is quite a mistake to suppose that when phosphorus is each combustion. The whole condenser is surrounded by a tall burnt in a combustion-tube in a slow current of air the wooden box, indicated by dotted lines in the figure, containing lower oxide, and not phosphorus pentoxide, is produced. pounded ice. To the end of the condenser is attached a wash. Scarcely a trace of phosphorous oxide is obtained under these cir. bottle, f, containing sulphuric acid, which serves to prevent cumstances, the white amorphous powder deposited being pent- access of moisture to the oxide condensed in the U-tube, and oxide. It is only when the current is at all rapid that phosphorous also to measure the rate of the current of air drawn through the oxide commences to be formed. Its advent is at once apparent, apparatus by the water pump. as it crystallizes all along the upper portion of the horizontal In making a preparation, as soon as the phosphorus, dried by combustion-tube in beautiful feathery crystals, which at once blotting-paper, has been introduced and the tube containing it melt is the finger is laid upon the exterior of the tube, while attached to the brass condenser, which at first is quite cold, the the pentoxide settles out along the bottom of the tube. After phosphorus is warmed to the igniting point and the pump set several less successful attempts to devise a method of producing working by turning on the water tap to which it is firmly attached. After about ten or fifteen minutes, crystals begin to combination (as determined from its halogen derivatives) and make their appearance in the U-tube ; the oxide then rapidly which is somewhere about 25-3, and another when in the free collects in the form of a waxy mass. The best refrigerator for state, which is approximately 20*9. Oxygen, too, is usually the U-tube is pounded ice; if salt is mixed with it, the oxide supposed to have two values, one of 7.8 when it is linked to condenses so rapidly in the first cooled portion of the condenser two different atoms, single linkage as it is termed, and another as to form a bridge and stop the operation until it is melted of 12'2 when doubly linked to one and the same atom of another down. When nearly half of the phosphorus is burnt, the brass element. If we subtract six times 7.8, that is deduct the coudenser is warmed by pouring in water heated to about 70°- specific volume due to six atoms of oxygen, from the specific 80° C., and the condenser is maintained at this temperature volume 130'2 of phosphorous oxide, we arrive at the number until about three-quarters of the phosphorus has been burnt, 83'4 for four atoms of phosphorus, or 20'9 for that of one atom. when the operation is stopped by slowly turning off the water If any of the oxygen atoms were doubly linked the number would working the pump.

be considerably less than 20-9, hence this number represents When phosphorus is burnt under these conditions, three the greatest possible value of the phosphorus in phosphorous oxides are produced ; more or less of the red suboxide P.O is oxide. always deposited in the immediate neighbourhood of the It would appear, therefore, that the phosphorus in phosburning phosphorus, a certain amount of pentoxide is formed phorous oxide possesses the same specific volume as free and retained in the glass tube beyond the seat of combus-phosphorus itself

, a result of interest in view of the fact tion and in the brass condenser, and phosphorous oxide is revealed by the determinations of molecular weight that there produced in large quantity, and, being considerably more vola- are four atoms of phosphorus in the molecule of the oxide just tile, is carried forward to the cooled condenser, any which may as there are in the molecule of free phosphorus itself. be deposited in the brass condenser during the earlier stages of The liquid oxide, considering that it contains such a highly the combustion being carried along into the in the refractive substance as phosphorus, possesses a remarkably low current of escaping nitrogen when the warm water is introduced power of refracting light. "Its resractive index at 27°:4 C. is into the brass condenser. Scarcely a trace of pentoxide escapes only 1'5349 for the red line of lithium, and 1.5614 for the blue through the glass wool filtering plug, the product in the U-tube hydrogen line G. Not only is the refractive index of phosphorus being almost pure phosphorous oxide. In the course of five (2.0677 for the red hydrogen line C) enormously reduced by its hours three such charges of phosphorus may be burnt out and the combination with oxygen, but the length of the spectrum is total phosphorous oxide produced, which should amount to at

reduced to about one-fifth. least twenty grams, can be condensed in the same U tube, the product from each charge being melted down into the bottle so as

Action of Light. to prevent choking of the tube. In order to free the product from any traces of impurity, it should be distilled in a slow current of it usually condenses after distillation, is remarkably sensitive to

Phosphorous oxide, in the white wax-like solid form in which absolutely clear liquid which soon solidifies to a snow-white light. Ten minutes exposure to bright sunshine suffice to turn

it” red, and after half an hour it is rendered quite dark red. mass of crystals. The tube should be at once sealed and, for a

The red substance which is formed is the red modification of reason which will be found under the Action of Light, kept in the dark.

phosphorus, but even after several months' exposure the amount

produced bas never been found to exceed 1 per cent. of the Molecular Composition of Phosphorous Oxiile.

weight of the oxide. The beautiful isolated crystals obtained Quantitative analysis of the substance whose properties and by sublimation in vacuo appear to be unaffected by light, but it mode of preparation have just been described of course yields is a curious fact that if one of them is melted by the warmth of numbers which agree with the empirical formula P,O3. But the hand, and the liquid globule afterwards suddenly cooled to as the oxide is volatile it was of the first importance to delermine The wax-like sorm, the latter becomes red on exposure to day. its vapour density, with the view of obtaining information light. Whether the reddening is due to the conversion of small regarding its molecular weight. This determination was the quantities of admixed yellow phosphorus into red phosphorus, more interesting from the fact that Prof. Victor Meyer had or to the decomposition of the waxy form of the oxide by light, previously found that the analogous oxides of arsenic and anti- there is not yet sufficient data to determine. mony gave vapour densities corresponding to the double molecular formulæ As,06 and S6,06, and also from the fact that

Action of Heat. the molecule of phosphorus itself is found to contain four atoms.

It has been seen that the oxide boils without decomposition The vapour density was determined by Hoffmann's well-known method in the Torricellian vacuum at the temperatures of boiling

at 173°'1. It may be heated in a closed tube to considerably

over 200° without change. It commences to decompose, howamyl alcohol (132°), oil of turpentine (1599) and aniline (184°).

ever, between 210° and 250°, becoming turbid from the separaThe numbers obtained from several such determinations are in

tion of solid decomposition products, one of which is free phosperfect accordance with the molecular weight corresponding to

phorus, which becomes more and more deeply coloured until at the double formula P,06. This result has been fully confirmed 300° it is quite red. At about 400° the oxide is totally decom, by a determination of the molecular weight by the totally different method of Raoult, which depends upon the degree of posed into solid products, consisting of both yellow and red

Occasionally, when lowering of the freezing point of a solvent

, in this case benzene, only the lower half of the tube has been immersed in the heating by the introduction of a small quantity of the substance under bath, the formation of crystals has been observed in the cooler going investigation.

portion of the tube, which appear to be identical with some Hence phosphorous oxide must be symbolized by the formula described in a previous communication to the Chemical Society P,08 and not P,03, phosphorus thus resembling its family which gave numbers on analysis agreeing with the formula relatives arsenic and antimony in the nature of its lower combination with oxygen.

P,O,, and which yielded a solution with water capable of re

ducing mercuric chloride to calomel. Hence the final decomPhysical Properties of Phosphorous Oxide.

position by heat may be expressed by the equation The specific gravity of the solid oxide at 21° C., compared with

5P-06 = 6P,05 + 8P, water at 4° is 2'135, and that of the liquid oxide at 24°:8 is but under suitable circumstances the intermediate formation of 19358. Hence there is about nine per cent. of contraction the teiroxide may occur according to the equation upon the passage of the liquid into the solid state.

2P,08 = 3P,0, + 2P. A somewbat interesting result has been obtained from the determination of the specific volume, that is, the number

Action of Oxygen. obtained by dividing the molecular weight by the density at the boiling point. The actual density, of course, cannot be experi- Phosphorous oxide takes up oxygen spontaneously at the mentally determined at the temperature of ebullition, but by ordinary temperature. It is provable, however, that the making a careful determination of the rate of expansion and oxygen only reacts in the cold with the vapour. For if a small knowing the density very precisely at some lower temperature quantity of the oxide is placed at the bottom of a glass Tube the density at the boiling point can be calculated. The value closed at one end and previously filled with oxygen, and the thus sound for the specific volume was 130-2. Now, phosphorus tube is sealed and left in the dark in an upright position, the is known to possess two specific volumes; one in the state of oxide is gradually converted to a voluminous mass of pentoxide,

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