Imagens das páginas
PDF
ePub

THE Russian Scientific Expedition to the Amu Daria was to set out on Monday last. The expedition will be commanded by the Grand Duke Nicholas Constantinovitch, assisted by Colonel Stoletoff and Dr. Moreff, secretary. It will include 25 persons, whose work will be divided into four sections :-(1) The Trigonometrical and Topographical. (2) The Meteorological Section, which will construct two stations on the Amu Daria, at one of which hourly observations will be made of all the meteorological phenomena. (3) The Ethnographical Statistical Section. (4) The Natural History Section.

THE meeting of French Astronomers took place last week at the Ministry of Public Instruction, under the presidency of M. Leverrier. It was composed of M. Dumeril, director of the Enseignement, the astronomers from Paris, Toulouse, and Marseilles Observatories, and Officers from the General Staff of the Trigonometrical Survey. Four sittings were held, and an account of them will be issued shortly. Steps have been taken for the determination of the latitude of Algiers, by telegraph. M. du Barail, Minister of War, and M. Saget, his StaffOfficer, visited the Observatory last Saturday, in order to see for themselves how the work may be begun without further delay.

THE additions to the Zoological Society's Gardens during the last week include four Bladder-nosed Seals (Cystophora cristata) from Greenland, presented by Capt. Alex. Gray; a Whitewinged Whydah Bird (Urobrachya albonotus) from West Africa, presented by Mr. J. Fairchild; a Rose-crested Cockatoo (Cacatua moluccensis) from the Moluccas, presented by Mr. H. Baldwin; an Azara,s Fox (Canis acara) from South America; a Snowy Owl (Nyctea nivea) from South America; a Greencheeked Amazon (Chrysotis viridigenalis) from Columbia, purchased.

ON THE REFRACTION OF SOUND*

THE principal object of this paper is to show that sound, instead of proceeding along the ground, is lifted or refracted upwards by the atmosphere in direct proportion to the upward diminution of the temperature; and hence to explain several phenomena of sound, and particularly the results of Prof. Tyn

dall's recent observations off the South Foreland.

The paper commences with the explanation of the effect of wind upon sound, viz., that this effect is due to the lifting of the sound from the ground, and not to its destruction, as is generally supposed. The lifting of the sound is shown to be due to the different velocities with which the air moves at the ground and at an elevation above it. Owing to friction and obstructions the air moves slower below than above, therefore sound moving against the wind moves faster below than above, and the bottom of the sound waves will thus get in advance of the upper part, and the effect of this will be to refract or turn the sound upwards; so that the rays of sound which would otherwise move horizontally along the ground actually move upwards in circular or more hyperbolic paths, and may thus, if there is sufficient dis tance, pass over the observer's head. This explanation was propounded by Prof. Stokes in 1857, but it was discovered independently by the author.

The paper then contains descriptions of experiments made with a view to establish this explanation.

These experiments were made with an electric ball, over a nearly flat meadow, and again over the same when it was nearly covered with snow, and it was found (as indeed it was expected) that the condition of the surface very materially modified the results in two ways. In the first place, a smooth surface like snow obstructs the wind less than grass, hence over snow the wind has less effect in lifting the sound moving against it than over grass; and it is inferred that a still greater difference would be found to exist in the case of smooth water. In the second

On the Refraction of Sound by the A mosphere, By Prof. Osborne Reynolds, Owens College, Manchester. Abstract of paper read before the Royal Society April 23.-Communicated by the Author.

place, the ends of the waves of sound travelling along in contact with the rough ground are continually destroyed by the rough. ness, and the sound from above slowly diverges down to replace that which is destroyed, and this divergence gradually weakens the intensity of the lower parts of the waves, so that, under ordinary circumstances, the sounds which pass above us are more intense than those we hear. The general conclusions drawn from these experiments are:

1. The velocity of wind over grass differs by at elevations of I and 8 feet, and by somewhat less over snow.

2. That when there is no wind, sound proceeding over a rough surface is destroyed at that surface, and is thus less intense below than above; owing to this cause the same sound would be heard at more than double the distance over snow at which it could be heard over grass.

3. That sounds proceeding with the wind are brought down to the ground in such a manner as to counterbalance the effect of the rough surface (2), and hence, contrary to the experiments of Delaroche, the range of sound over rough ground is greater with the wind than at right angles to its direction or than when there is no wind. When the wind is very strong it would bring the sound down too fast in its own direction, and then the sound would be heard farthest in some direction inclined to that of the wind though not at right angles.

4. That sounds proceeding against the wind are lifted off the ground, and hence the range is diminished at low elevations. But that the sound is not destroyed and may be heard from positions sufficiently high (or if the source of sound be raised) with even greater distinctness than at the same distances with the wind.

5. In all cases where the sound was lifted there was evidence of diverging rays. Thus although on one occasion the full intensity was lost when standing up at 40 yards the sound could be faintly and discontinuously heard up to 70 yards. And on raising the head the sound did not at once strike the ear with its full intensity nor yet increase quite gradually; but by a series of steps and fluctuations in which the different notes of sound were vari. o:sly represented, showing that the diverging sound proceeds in rays separated by rays of interference.

On one occasion it was found that with the wind sound could be heard at 360 yards from the bell at all elevations, whereas at right angles it could be only heard for 200 yards standing up, and not so far at the ground; and against the wind it was lost at 30 yards at the ground, at 70 yards standing up, and 160 yards at an elevation of 30 feet, although it could be distinctly heard at this latter point from a few feet higher.

It hence appears that these results agree so well with what might be expected from the theory as to place its truth and completeness beyond question.

sound to another phenomenon which admits of a somewhat simiThe author then goes on to argue from the action of wind upon lar explanation. The effect of wind together with that of a rough surface in lifting the sound may be shown to account for many of sounds can be heard at different times; and it gives a reason for the apparently capricious variations in the intensity with which the custom which prevails of elevating church bells, platforms, &c., where the sounds are intended to be heard at a distance. But it does not explain a fact, which has often been observed, namely, that distant sounds can be heard much better during the night than during the day, and on dull cloudy days better than on bright hot days. This phenomena has engaged the attention of Humboldt, Delaroche, and recently of Prof. Tyndall, who have all assumed that the sound is obstructed or destroyed in the bright hot air, and have suggested causes which they thought might produce this effect. These suggestions are all more or less open to objection, and none of them meet the difficulty that any heterogeneous condition of the air which could obstruct sound must more or less refract or reflect light and so render vision indistinct. In this paper the author gives another explanation, in which he shows how, as in the case of wind, the sound may be lifted and not destroyed.

it to move faster below than above, any other cause which proIt is argued that since wind raised the sound simply by causing duces such a difference in velocity will lift the sound in the same way. And since the velocity of sound through air increases with the temperature-every degree from 32 to 70 adding 1 foot per second to the velocity-therefore an upward diminution in the temperature of the air must produce a similar effect to that of wind and lift the sound. Whereas Mr. Glaisher has shown by his balloon observations that such a diminution of temperature exists, and further he has shown that when the sun is shining with a clear sky the variation from the surface is 1° for every

100 ft., and that with a cloudy sky it is only half what it is with a clear sky. These results were from the mean of his observations; under exceptional circumstances the variations were both greater and less. It is hence shown that rays of sound otherwise horizontal would be bent upwards in the form of circles, the radii of which with a clear sky are 110,000 ft., and with a cloudy sky 220,000 ft., so that the refraction is double as great on bright hot days as it is when the sky is cloudy, and still more under exceptional circumstances, and comparing day with night.

It is then shown by calculation that the greatest refraction-110,000 ft. radius-is sufficient to render sound from

a cliff 235 ft. high inaudible on a ship's deck 20 ft. high at 1 miles, except such sound as might reach the observer by divergence from the waves above, whereas when

the refraction is least-220,000 ft. radius-or where the sky is cloudy, the range would be extended at 24 miles with a similar extension for the diverging waves. It is hence inferred that the phenomenon which Prof. Tyndall observed on July 3, and other days--namely that when the air was still and the sun was hot he could not hear guns and sounds from the cliffs of South Foreland, 235 ft. high, for more than two miles, whereas when the sky clouded, the range immediately extended to three miles, and as evening approached much farther, was due, not so much to stoppage or to reflection of the sound by invisible vapour as Prof. Tyndall has supposed, but to the sounds being lifted over his head in the manner described; and that had he been able to ascend 30 ft. up the mast, he might at any time have extended the range of the sound by a quarter of a mile at least. Or had the instruments on the top of the cliff been compared with similar instruments at the bottom, a very marked difference would have been found in the distances at which they could be heard.

It seems that there were instruments at the bottom, and it is singular that throughout his report Prof. Tyndall makes no comment on their performance, unless they were at once found to be so inferior to those at the top that no further notice was taken of them; this seems possible, since beyond mentioning that they were there, Prof. Tyndall throughout his report never refers to them.

It also seems that besides those results of Prof. Tyndall's experiments, there are many other phenomena connected with sound, of which this refraction affords an explanation, such as the very great distances to which the sound of meteors has been heard as well as the distinctness of distant thunder. When near, guns make a louder and more distinctive sound than thunder, although thunder is usually heard to much greater distances. In hilly countries, or under exceptional circumstances, sounds are sometimes heard at surprising distances. When the Naval Review was at Portsmouth, the volleys of artillery were very generally heard in Suffolk, a distance of 150 miles. The explanation being that owing to refraction (as well as to the other causes) only under exceptional circumstances that distant sounds originating low down are heard near the ground with anything like their full distinctness, and that any elevation either of the observer or of the source of sound above the intervening ground causes a corresponding increase in the distance at which the sound can be heard.

SCIENTIFIC SERIALS

Memorie della Societa degli Spectroscopisti Italiani, February.Father Secchi contributes a paper On his Observations of Solar Prominences from April 23 to October 2, 1873. From his tables it appears that the sun was observed on 127 days, when 1,052 prominences were seen, being more than 8 a day, the maximum number visible on any one day was 13, and the minimum 2. The greatest number of prominences over 64" high occurred in lat. 30° 40' N. and 20° 30' S. The greatest number of prominences of all kinds were in lat. 20° 30' N. and 10° 20' S. The same author also makes some remarks on the spectroscopic observations of the transit of Venus.

He

Astronomische Nachrichten, Nos. 1,980-1,981.-These numbers contain a large quantity of observations of positions of the minor planets and comets made in 1873 by Leopold Schulhof. also gives the positions of more than 100 variable stars, with remarks on a new variable position for 1850, RA 23° 10′ 35′′ Dec. - 19° 39'7. Prof. Peters gives the position of Planet 135, Feb. 18, 1874, at 14h. 37m. 40s., Hamilton College, M.T., RA 11h. 19m. 42'75. Dec. + 4° 25′ 5" 11 mag. G. Spoerer gives

the positions of spots and prominences for February last. J. Palisa gives the position of the planet discovered by him on March 18, 4h. 46m. 39s. RA 12h. 22m 2'123. Dec. -3° 19' 33" 4 No. 1,982 contains a long paper On a Method of Computing Absolute Perturbation, being in great measure similar to that of Laplace.

Journal of the Franklin Institute, March.-This number contains an account, by Mr. Crew, of the "prismoidal" onerail railway (of his invention), of which he has made two years trial in Alabama, with encouraging results. The cats are kept securely on the prismoidal track by a combination of wheels; a centre one, at either end, on the rail, kept on the track by revolving flanged wheels at either side; and wheels on the sides of the prismoid, with strong wrought-iron bars to the side of the car; these keep the car upright. One proposed application of the system is that of elevated rapid transit by steam through crowded streets in populous cities. As to speed, Mr. Crew thinks even 100 miles an hour would be possible; there is no Principles of Shop Manipulation for Engineering Apprentices; oscillation through lateral motion. Mr. Richards continues his treating of belts, gearing, hydraulic and pneumatic apparatas as means of transmitting power, and of "machinery of applica tion" of power.-Mr. Isherwood points out a method of ascer taining what portion of the feed-water admitted to a boiler is entrained in the form of spray by the escaping steam.-Details with reference to the Girard Avenue Bridge (which will form the chief entrance to the West Park, at Philadelphia), are furnished by Mr. Hering.-Prof. Thurston claims for Count Rumford a higher place in connection with thermo-dynamics than has hitherto been assigned to him; affirming that he first, and half a century before Joule, determined with almost perfect accuracy the mechanical equivalent of heat, while the sole credit of discovering the true nature of heat is due to him.-We may note, in addition, a paper On Railway Crossings and Turnouts, by Mr. Evans, and one On the Sanitary Care and Utilisation of Refuse in Cities, by Dr. Leas, who describes, more especially, the system followed in Baltimore.

SOCIETIES AND ACADEMIES
LONDON

Royal Society, April 23.-On some points connected with the Circulation of the Blood, arrived at from a study of the Sphygmograph Trace, by A. H. Garrod, B. A., Fellow of St. John's College, Cambridge.

x =

=

The author commences by giving a table containing a fresh series of measurements of the ratio borne by the cardiosystole to its component beat in the cardiograph trace. These tend strongly to substantiate the law previously published by him, viz., that the length of the cardiosystole is const int for any given pulse rate, and that varies as the square root of the length of the pulse-beat only, being found from the equation xy = 20r when the pulse-rate and y the ratio borne by the candiosystole to the whole beat. A similar series of fresh measurements are given in proof of the law previously published by him, that in the sphygmograph trace from the radial artery at the wrist, the length of the sphyg mosystolet is constant for any given pulse-rate, but varies as the cube-root of the length of the pulse-beat, it being found from the equation = 47x, where x = the pulse-rate, and y = the ratio borne by the sphygmosystole to the whole beat.

By measurement of sphygmograph tracings from the carotid in the neck and posterior tibial artery at the ankle, it is then shown that the length of the sphygmograph in those arteries is exactly the same as in the radial; so that the above-stated law as to the length of the sphygmosystole in the latter applies to them also, and must therefore equally apply to the pulse in the

aorta.

Such being the case, by comparing the equations for finding the length of the cardiosystole with that for finding the aortic sphygmosystole, the relation between the whole cardiac systolic act and the time during which the aortic valve remains open can be estimated with facility; for by subtracting the shorter sphygmosystole from the longer cardiosystole a remainder is obtained which can be nothing else than the expression of the

The cardiosystole is the interval between the commencement of the systole and the closure of the aortic valve in each revolution.

The sphygmosystole is the interval between the opening and closure of the aortic valve in each cardiac revolution.

time occupied by the ventricle at the commencement of its systole in raising its internal pressure to that of the blood in the aorta, which must occur before the aortic valve can open up. This interval is named the syspasis. Its length is found to decrease ve y rapidly with increase in the pulse-rate, and to become nil at a pulse-rate of 170 a minute. An attempt is made to explain these phenomena.

If the above considerations are correct, certain independently obtained measurements ought on comparison to correspond; for by reference to one of the papers in the Society's Proceedings it is shown that the length of the there-termed second cardioarterial interval (which may be called the second cardio-radial interval, as the artery under consideration was the radial), can only represent the time taken by the second or dicrotic wave of the pulse in travelling from the aortic valve to the wrist. This being so, there is every à priori reason in favour of the earlier primary wave taking the same time in going the same distance; which can be expressed in other terms by saying that the length of the first cardio-radial interval, from which that of the syspasis has been subtracted, ought to be exactly the same as that of the second cardio-radial interval. That such is the case is proved by the two measurements, which have been arrived at independently, agreeing in all cases to three places of decimals, which is great evidence in favour of the accuracy of the methods and arguments employed.

The latter part of the paper is occupied with the description of and the results obtained by the employment of a doublesphygmograph, by means of which simultaneous tracings are taken from two arteries at very different distances from the heart. The arteries experimented on are the radial at the wrist and the posterior tibial behind the ankle, 29 and 524 inches respectively from the aortic valves. From the resulting traces the time occupied by the pulse-wave in travelling the differenceof distance (525-29) = 23.5 inches is given-is found to be 0.0012 of a minute in a pulse of 75 a minute, and it is shown that this varies very little with difference in pulse-rate, as other considerations would lead us to expect; it is also proved that there is a marked acceleration of the pulse-wave as it gets further from the heart.

By superposing the simultaneous trace from the wrist on that from the ankle, direct verification is obtained of the earlier proposition, that the sphygmosystole at the wrist and at the ankle are of exactly similar duration. The peculiarities of the ankle trace are also referred to.

Geological Society, April 15.-John Evans, F.R.S., president, in the chair.-The following communications were read: About Polar Glaciation, by J. F. Campbell. The author commenced by referring to a reported statement of Prof. Agassiz, to the effect that he supposed the northern hemisphere to have been covered in glacial times from the pole to the equator by a solid cap of ice. He described his observations made during thirty-three years, and especially those of last summer, when he travelled from England past the North Cape to Archangel, and thence by land to the Caucasus, Crimea, Greece, and the south of Europe. His principal results were as follows:-In advancing southwards through Russia a range of low drift hills occurs about 60° N. lat., which may perhaps form part of a circular terminal moraine left by a retreating polar ice-cap; large grooved and polished stones of northern origin reach 55° N. lat. at Nijni Novgorod, but further cast and south no such stones could be seen. The highest drift beds along the whole course of the Volga seem to have been arranged by water moving southwards. In America northern boulders are lost about 39°, in Germany about 55°, and in Eastern Russia about 56° N. lat., where the trains end and fine gravel and sand cover the solid rocks. action, in the form either of glaciers or of icebergs, is necessary to account for the transport of large stones over the plains, and the action of moving water to account for drift carried farther south. There are no indications of a continuous solid ice-cap flowing southward over plains in Europe and America to, or nearly to, the equator; but a great deal was to be found on shore to prove ancient ocean circulation of equatorial and polar currents, like those which now move in the Atlantic, and much to prove the former existence of very large local ice-systems in places where no glaciers now exist.-Note regarding the Occurrence of Jade in the Karakash Valley, on the southern borders of Turkestan, by Dr. Ferdinand Stoliczka, Naturalist attached to the Yarkund Mission. In this paper the author described the jade-mines on the right bank of the Karakash river formerly worked by the Chinese There are about 120 holes in the side

Ice

of the hill, and these at a little distance look like pigeon-holes. The rocks are a thin-bedded, rather sandy syenitic gneiss, micaand hornblende-schists, traversed by veins of a white mineral, apparently zeolitic, which in turn are traversed by veins of jade.

Zoological Society, April 21.-Viscount Walden, F.R.S., president, in the chair.-The secretary read a report on the additions that had been made to the Society's Menagerie during the month of March 1874. Amongst these particular attention was called to a scarce Parrot (Chrysotis finschi), of which a specimen had been presented by Mrs. Chivers.-A communication was read from Mr. Morton Allport On the capture of a Grilse in the River Derwent, in Tasmania, showing that the salmon had really been successfully introduced into the colony.-Communications were read from Dr. J. E. Gray, F.R.S., On the very young of the Jaguar, Felis (Leopardus) onca; On the shorttailed Armadillo, Muletia septemcincta; On the young of the Bosch Vark, Patomocharus africanus, from Madagascar; and On the Skulls of the Leopard in the British Museum.-A communication was read from Dr. O. Finsch, containing the description of a new species of Penguin, from New Zealand, which he proposed to call Eudyptula albosignata.—Mr. Edwin Ward exbibited the skull and horns of a fine specimen of the Persian Stag (Cervus maral) from the Crimea.-A communication was read from Capt. W. H. Unwin, containing an account of the breeding of the Golden Eagle (Aquila chrysaetos) in North-Western India.--Mr. J. E. Harting read a paper On a new species of Tringa, from St. Paul's Island, Alaska, which he proposed to name Tringa gracilis.-A communication was read from Lieut. R. Wardlaw Ramsay, giving the description of an apparently new species of Woodpecker, which he had obtained in a teakforest, about six miles to the north of Tanghoo in British Burmah. Mr. Ramsay proposed to name it Gecinus erythropygius.—Messrs. W. T. Branford and H. E. Dresser read a monograph of the genus Saxicola, Beechstein, being an attempt to reduce into some order the excessively confused nomenclature of the species composing this genus.

Royal Horticultural Society, April 15.-Scientific Committee.-M. T. Masters, M.D., F.R.S., in the chair.—Mr. Worthington Smith exhibited a drawing of a very curious fasciation in the aerial roots of Aerides crispum, in which the roots presented the curious flattened appearance so often met with in the branches of the ash, the shoots of asparagus, &c.—Mr. W. G. Smith also showed a drawing of the very rare Angræcum ellisii, from the collection of Mr. Day, of Tottenham. Mr. Smith remarked that the flowers turn brown when bruised.—Mr. Smith also showed a wood-engraving made on the wood of green ebony, Brya ebenus. Mr. Smith reported that for engraving purposes this was as good as bad box.-Prof. Thiselton Dyer showed dried specimens of a variety of Hibiscus rosa-sinensis from Zanzibar, where it was found wild by Dr. Kirk. The petals are palmately cut, as in Clarkia, Schizopetalum, &c. Dr. Masters made some remarks on the analogy the divided petals of this plant presented with the stamens of mallows, which it is now supposed consist of five primary organs, subsequently dividing into numerous anther-bearing filaments. It is doubtful whether Hibiscus rosa-sinensis has been heretofore observed in a truly wild condition. The discovery of the plant in east tropical Africa is therefore particularly interesting. It is possible, however, that it may prove a distinct species.-Prof. Thiselton Dyer also showed an elegant white fungus, having the appearance of lace, from Santarem. The Rev. M. J. Berkeley considered it probable that it was the fungus published by Kunze as Rhizomorpha corynephora. -Mr. Andrew Murray exhibited a fungoid production existing on trees over a considerable space in the Yosemite Valley, in California. Mr. Berkeley considered it near to the fungus called Dothidea morbosa, but there was also a gall on the same shoot.Mr. Murray exhibited larvæ of a beetle closely allied to Hamma. ticherus heros, a beetle very destructive to timber in Germany, found feeding on the roots of fir near Enfield. Specimens of the perfect living insect have from time to time been found in the gun-stocks of walnut wood in the small-arms factory. It seems, therefore, a fair inference that the insects had escaped thence, and may perhaps have become naturalised-a most undesirable thing, for the larva is very destructive to timber. Mr. Blenkins remarked that he was familiar with the insect in the Crimea.

General Meeting.-H. Little in the chair. - The Rev. M. J. Berkeley commented on the plants exhibited. Arthropodium cirrhatum was an interesting plant of striking habit from New Zealand. When first introduced into this country, some years ago, it was supposed to have come from New Holland.

:

Physical Society, April 18.—Dr. Gladstone, F.R.S., in the chair.-Dr. W. H. Stone read a paper On Wind Pressures in the human chest during performance on wind instruments. The author's object was to ascertain (1) what was the extreme height of a column of water which could be supported by the muscular act of expiration transmitted by the lips this was found to be about 6 ft.; and (2) what was the actual pressure corresponding to the full production of a note on each of the principal wind instruments. It was found that with the majority of wind instruments the pressure required for the high notes is considerably greater than that required for the low notes, each instrument having a pressure-ratio of its own. The clarinet is an exception to the rule.-Mr. Tribe illustrated by experiments the action of hydrogen upon finely divided metals, such as are produced by precipitation.

EDINBURGH

Royal Physical Society, April 22.-R. Scot Skirving, president, in the chair. Recent Modes of determining the Impurity of Milk, by J. Falconer King, City Analyst. The only sure way to determine the quality of milk is to make a proper and careful chemical analysis of it.-Additional Note on the Suspension of Clay in Water, by Wm. Durham. Finely-powdered silica was found to behave in a manner generally similar to clay. Experiments seem to show that each solution has a specific capacity of sustaining clay, and also that this capacity varies in a specific manner according to the strength of the solu tion.-Note on the Formation of Boulder Clay, by D. J. Brown. Mr. Brown advocated that the usually accepted theory of the land origin of boulder clay would not explain the nature of this remarkable deposit, and considered that it was formed at the line of junction of the Arctic glacier with the sea. -On Fused Stones, showing Columnar Structure from a Pictish Tower, by the Rev. Jas. M. Joass, Golspie. These stones, in their columnar structure, illustrate, though on a small scale, an important geological phenomenon. The instance usually cited in illustration of the development of columnar structure in a melted mass is that of grain-tin, which forms rude columns on cooling. The author ventures to think that these fused stones afford a new and rather better illustration of the geological phenomenon, more closely analogous to the case of lavas, inasmuch as we have, in fact, a fused silicate, an artificial lava, forming columns the same in character as those of the Giant's Causeway, Samson's Ribs, or the pillars of Fingal's far-famed cave.

PARIS

Academy of Sciences, April 20.-M. Bertrand in the chair. -The following communications were read :-Letter relating to a calculation, by Pouillet, on the cooling of the sun's mass, by M. Faye. The author showed that Pouillet's calculation tacitly implied that the sun's mass was not susceptible of contraction, and again restated his belief that solar radiation is not maintained by external causes, but is to be looked for in the formation of the sun itself, and in the enormity of its mass.-Observations concerning a communication, by M. Crocé Spinelli, on the lines of aqueous vapour in the solar spectrum, a letter from P. Secchi to the perpetual secretary. The author stated, that although the elements of water would be dissociated at the high temperature of the sun, their combination might take place in the ascending currents accompanying spots and eruptions owing to the lowering of temperature in these currents produced by expansion.-Tenth memoir on the formation of various crystalline substances in capillary spaces, by M. Becquerel.-New researches on the cyanogen series, by M. Berthelot. A continuation of this author's valuable researches in thermo-chemistry.-Heat of formation of the Cyanogen compounds, by M. Berthelot.-On Phylloxera and the American vines at Roquemaure (Gard), a note by M. J. E. Planchon.-Collimating level and its employment for foggy horizons, by M. G. M. Goulier.-On Orometric dials, specially applicable to pocket barometers, by the same author. On partial differential equations which can be integrated without arbitrary functions, by M. de Pistoye.On the "singular points" of algebraical plane curves, by Mr. Halphen. On the role of salts in the action of potable waters on lead, by M. Fordos. The author recommended, as the results of his experiments, the filtration of all water issuing from leaden conduits.-Mode of preservation of the wood employed in large manufactures and in railways, by M. Hubert. The preservative is hydrated ferric oxide. On the absorption of oxygen and the emission of carbonic acid by leaves kept in darkness, by MM. P. P. Dehérain and H. Moissan. The

authors have proved that leaves kept in the dark give off a quantity of CO, increasing with the temperature, that the quantity of CO, given off is comparable to that given off by cold-blooded animals, that the leaves absorb more oxygen than they give off CO, and that they continue to evolve ČO, in an atmosphere deprived of oxygen.-Facts concerning the vitration of the air in sonorous pipes, by M. E. Gripon.-On a new thermo-electric pile, by M. C. C. Clamond. On a volume regulator for gas currents, by M. H. Giroud. On tetra-iodide of carbon, by M. G. Gustavson. This substance has been obtained by the action of tetrachloride of carbon upon dialuminic hexiodide, according to the equation 3C1, + 2AlI. = 3CI, + 2Al2Cl; the two substances being dissolved in carbon disulphide. It was described as a red crystalline substance decomposed by heating in the air into CO2 and free iodine.-New researches on black phosphorus, by M. Blondlot.-Action of pure hydrogen on silver nitrate, by M. H. Pellet. The author stated that a neutral or slightly acid solution of the salt is not reduced in the cold by pure hydrogen, and that an alkaline solution is reduced in the cold to an extent proporreducing action.-Researches on soluble phosphates used in agritional to its alkalinity, elevation of temperature increasing the culture, by M. A. Millot.-On the direct determination of the degree of intensity of explosive mixtures: application of the method to gunpowders, by M. Chabrier.-Action of bromine on dibromsuccinic acid; tribromsuccinic acid, by M. E. Bourgoin. The following substances are obtained by the action of bromine and water on the acid: tribromsuccinic and dibrom maleic acids and dibrominated ethylene dibromide.-On the alcohols contained in the acid liquors of starch manufactories and in the products of the butyric fermentation of glucose, by M. G. Bouchardat. These are ethylic, normal propylic, and butylic alcohols.-On the determination of alcohol in water, wines and saccharine liquors, by M. Salleron.-General method for the transformation of alcohols into nitric ethers, by M. P. Champion. The reagent employed is nitro-sulphuric acid.-On phenyl-allyl, by M. B. Radziszewski. -On pyrogallol in presence of iron salts, by M. E. Jacquemin. volatile acids of wine, by the same author.-Movements excited -On the colouring matter of wine, by M. E. Duclaux.-On the in the stamens of Mahonia and Berberis; anatomical conditions of this movement, by M. E. Heckel.-On the direction of the wind in the high and low (atmospheric) regions during the storm of April 13, 1874, by M. Chapelas.-During the meeting a com. mission was appointed to prepare a list of candidates for the vacancy of foreign associate caused by the death of M. De la Rive.

BOOKS RECEIVED

ENGLISH.-Handbook of Practical Telegraphy. 6th edit.: R. S. Culley (Longmans).-Mental Physiology: W. B. Carpenter (H. S. King & Co.)The Design and Construction of Harbours: Thos. Stevenson (A & C. Black) -Our Inheritance in the Great Pyramid: C. Piazzi Smyth (Isbister & Co.k -Longevity: John Gardner (H. S. King & Co.).-The New Chemistry: Josiah P. Cooke (H. S King & Co.).-Hydrostatics and Pneumatics: Lardner and Loewy (Lockwood).-Geology of Suffolk: J. R Taylor (White).-Toe Universe and the Coming Transits: R. A. Proctor (Longmans)-Hayda's Dictionary of Dates. 14th edit.: B. Vincent (Moxon).

[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][ocr errors][merged small][ocr errors][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small]
« AnteriorContinuar »