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f black powder could be as well and even more readily secured German experimenters directed their attention not merely to the in the thorough blending or mixing together of batches pre proportions in which the powder ingredients are employed, but cnting some variation in regard to density, hardness, or other also to a modification in the character of charcoal, and the Latures, as by aiming at an approach to absolute uniformity in success attending their labours in these directions led to the he characters of each individual mass composing a charge. practically simultaneous production, by Mr. Heidemann at the It the time that our attention was first actively given to this Westphalia Powder Works, and Mr. Düttenhofer at the Rottlabject of the modification of the ballistic properties of powder, weil Works near Hamburg, of a prismatic powder of cocoahad already been to some extent dealt with in the United brown colour, consisting of salt petre in somewhat higher kates by Rodman and Doremus, and the latter was the first to proportion, of sulphur in much lower proportion, than in rojose the application, as charges for guns, of powder-masses normal black powder, and of very slightly burned charcoal, roduced by the compression of coarsely grained powder into similar in composition to the charcoal (charbon roux) which joulds of prismatic form. In Russia the first step was taken to Violette, a French chemist, first produced in 1847 by the action luire the results arrived at by Doremus, and to adopt a prismatic of superheated steam upon wood or other vegetable matter, and wwder for use in guns of large calibre.

which he proposed for employment in the manufacture of Side by side with the development and perfection of the sporting powder. These brown prismatic powders (or cocoaManufacture of prismatic powder in Rnssia, Germany, and in powders," as they were termed from their colour), are disbis country, new experiments on the production of powder- tinguished from black powder not only by their appearance, but asso suitable, by their comparatively gradual action, for also by their very slow combustion in open air, by their comweployment in the very large charges required for the heavy paratively gradual and long-sustained action when used in guns, millery of the present day, by the powerful compression of and by the simple character of their products of explosion as stares of more or less finely broken up powder-cake into compared with those of black powder. As the oxidizing inLues of greater size than those of the pebble, pellet, and gredient, saltpetre, is contained, in brown or cocoa powder, in visma powders, were actively pursued in Italy, and also by our larger proportion relatively to the oxidizable components, sulphur Be Government Committee on Explosives, and the outcome of and charcoal, than in black powder, these become fully oxidized, sry exhaustive practical investigations were the very efficient while the products of explosion of the latter contain, on the lussano powder, or foudre progressif, of the Italians, and the other hand, larger proportions of unoxidized material, or only alder and large cylindrical powders known as P2 and C?, partially oxidized products. Moreover, there is produced upon Tuduced at Waltham Abbey, which scarcely vied, however, the explosion of brown powder a relatively very large amount rab the Italian powder in the uniformity of their ballistic of water.vapour, not merely because the finished powder conincperties.

tains a larger proportion of water than black powder, but also Kesearches carried out by Captain Noble and the lecturer some because the very slightly charred wood or straw used in the 213 ago with a series of gunpowders differing considerably in brown powder is much richer in hydrogen than black charcoal, as position from each other, indicated that advantages might be and therefore furnishes by its oxidation a considerable amount scured in the production of powders for heavy guns by so modi- of water. The total volume of gas furnished by the brown og the proportions of the constituents (e.g: by considerably powder (at oo C. and 760 mm. barometer) is only about 200 leasing the proportion of charcoal and reducing the proportion volumes per kilogramme of powder, against 278 volumes

sulphur) as to give rise to the production of a much greater furnished by a normal sample of black powder, but the amount raume of gas, and at the same time to diminish the heat developed of water-vapour furnished upon its explosion is about three the explosion.

times that produced from black powder, and this would make These researches served, among other purposes, to throw con- the volume of gas and vapour developed by the two powders berable light upon the cause of the wearing or erosive action of about equal if the heat of its explosion were the same in the under-explosions upon the inner surface of the gun, which in two cases; the actual temperature produced by the explosion lates may produce so serious a deterioration of the arm as to of brown powder, is, however, somewhat the higher of Ianish the velocity of projection considerably, and so affect the the two. euracy of shooting, a deterioration which increases in extent Although the smoke produced upon firing a charge of brown an increasing ratio to the size of the guns, in consequence, powder from a gun appears at first but little different in densebonusly, as the large increase in the weight of the charges fired. ness to that of black powder, it certainly disperses much more

Several causes undoubtedly combine to bring about the wear rapidly, a difference which is probably due to the speedy absorpS away of the gun's bore, which is especially great where the tion, by solution, of the finely divided potassium salts by the worlacts of explosion, while under the maximum pressure, can large proportion of water-vapour distributed throughout the socage between the projectile and the bore of the gun. 'The called smoke. Tral velocity with which the very highly heated gaseous and This class of powder was substituted with considerable advanqaid (fused solid) products of explosion sweep over the heated tage for black powder in guns of comparatively large calibre ; kwiace of the metal gives rise to a displacement of the particles nevertheless it became desirable to attain even slower or more romposing it, which increases as the surface becomes roughened gradual action in the case of the very large charges required for y the first action upon the least compact portions of the metal, guns of the heaviest calibres, such as those which propel shot of nad thus opposes greater resistance; at the same time, the about 2000 pounds weight. Accordingly, the brown powder has rfect of the high temperature to which the surface is raised is been modified in regard to the proportions of its ingredients to - reduce its rigidity and power of resisting the force of the suit these conditions, while, on the other hand, powder interSipos torrent, and lastly some amount of chemical action mediate with respect to rapidity of action between black pebble pon the metal, by certain of the highly heated non-gaseous powder and the brown powder, has been found more suitable products of explosion, contributes towards an increase in the than the former for use in guns of moderately large calibre. Trive effects. A series of careful experiments made by

The recent successful adaptation of machine guns and comagain Noble with powders of different composition, and with paratively large quick-firing gunz to naval service, more especially her explosives, afforded decisive evidence that the material for the defence of ships against attack by torpedo boats, &c., kuch furnished the largest proportion of gaseous products, and has rendered the provision of a powder for use with them, he caplosion of which was attended by the development of the which would produce comparatively little or no smoke, a matter imaalleat amount of heat, exerted least erosive action.

of very considerable importance, inasmuch as the efficiency of It is probable that important changes in the composition of such defence must be greatly diminished by the circumstance wwders manufactured by us for our heavy guns would have that, after a very brief use of the guns with black powder, the selted from those researches

, but in the meantime, two objects against which their fire is destined to operate, become cient German gunpowder manufacturers had occupied them more or less completely hidden from those directing them, by elves independently, and simultaneously

, with the important the dense veil of powder-smoke produced. Hence much attencaclical question of producing some more suitable powder for tion has been directed during the last few years to the production Seavy guns than the various new forms of ordinary black of smokeless, or nearly smokeless powders for naval use in the por der, the rate of burning of which, especially when confined above directions. At the same time, the views of many military ha dose chamber, was, after all, reduced only in a moderate authorities regarding the importance of dispensing with smoke degree by the increase in the size of the masses, and by such in land engagements has also created a demand, the apparent berease in their density as it was practicable to attain. The urgency of which has been increased by various circumstances,

GRLEN

RED

GREEN

RED

RED

RED

GREEN

for a smokeless powder suitable for field artillery and small SOLAR HALOS AND PARHELIA. arms.

The properties of ammonium nitrate, of which the products! THE recent appearance of solar and lunar halos, pubela of decomposition by heat are, in addition to water-vapour,

and paraselene, has called forth a considerable amour entirely gaseous, have rendered it a tempting material to work correspondence from all parts of the country, and the accomaya upon in the hands of those who have striven to produce a smoke ing figure may be taken as a composite representation des less powder, but its deliquescent character has been the chief solar phenomenon observed. A glance at the times at vkgs obstacle to its application as a component of an explosive agent they occurred earliest in places of highest latitudes. At Denife!

I the halos were observed on the 29th ult., makes it apparent Us susceptible of substitution for black powder for service purposes.

A German chemical engineer, F. Gäus, conceived that, by in in lat. 54°, the halo, with its attendant parhelia, was abserve corporating charcoal and saltpetre with a particular proportion

at 1.34 p.m., and the whole phenomenon disappeared at al of ammonium nitrate, he had produced an explosive material p.m.; at Burton-on-Trent, lat. 52° 48, the halos and partea which did not partake of the hygroscopic character common to were first observed at 2 p.m., and lasted more or less distingh other ammonium-nitrate mixtures, and that, by its explosion, the until 3 p.m. ; whilst about a degree south of this, at Ozilx potassium in the saltpetre formed a volatile combination with Colnbrook, and Walton-on-Thames, the phenomena more nitrogen and hydrogen, a potassium amide, so that, although from about 3.30 to 4.30. The uniform difference in the time containing nearly half its weight of potassium salt, it would when the halos were observed at the places of different latiteks furnish

only volatile products. The views of Mr. Gäus regarding necessarily follows from the fact that they are farmed by = the changes which his so-called amide powder undergoes upon action upon solar rays of prismatic crystals of ice suspendent explosion were not borne out by existing chemical knowledge, in the air by the ascending currents which especially stara while the powder compounded in accordance with his views the spring and autumn. Those prisms that are in such posits proved to be by no means smokeless, and was certainly not non

that the rays from the sun in transmission through there alle hygroscopic. Mr. Heidemann has, however, been successful, minimum deviation are the cause of the formation of halos, as by modifications of Gäus's prescription and by application of his since the angular distance of the sun equal to minimum devuda own special experience in powder-manufacture, in producing an is about 22°, this must be the radius of the halo, and there ammonium-nitrate powder possessed of remarkable ballistic ternal circle, being produced by two such refractions in successes properties, furnishing comparatively little smoke, which speedily has a radius of about 46°. disperses, and exhibiting the hygroscopic characteristics of am

The halos recently observed do not differ in the main fres monium-nitrate preparations in a decidedly less degree than any those frequently seen in higher latitudes, and consisting on other hitherto prepared. The powder, while yielding, a very without, and at an angular distance of 22 or 23°: (2. a zor!

a first circle or halo concentric with the sun, red within, vale brown powder, is considerably slower than the latter; the circle or halo, similar to the preceding, but at an angular charge required to produce equal ballistic results is less, while the chamber-pressure developed is lower, and the pressures along the chase of the gun are higher, than in the case of brown powder.

The ammonium-nitrate powder contains, in its normal, dried condition, more water than even brown powder ; it does not exhibit any great tendency to absorb moisture from an ordinarily dry or even a somewhat moist atmosphere, but if the

1 amount of atmospheric moisture approaches saturation, it will rapidly absorb water, and when once the process begins it continues rapidly, the powder-masses becoming speedily quite pasty. The charges for quick-firing guns are enclosed in metal cases, in which they are securely sealed up; the powder is therefore prevented from absorbing moisture from the external air, but it has been found that if the cartridges are kept for long periods in

a was seen at 3.35 p.m.; b at 3.45 p.ro : cand d'ar z zap.m. *** ships' magazines, in which, from their position relatively to the

fat 4. to p.m. ships' boilers, the temperature is more or less elevated, some times for considerable periods, the expulsion of water from some tance of 46°; (3) a portion of the parhelic circle appearing is portions of the powder masses composing the hermetically sealed zontal and diametral, and at the points of junction of this crak charge, and its consequent irregular distribution, may give rise with the two halos, there is increased luminosity, which are to want of uniformity in the action of the powder, and to the been taken for images of the sun ; (4) horizontal ares, tangu occasional development of high pressures. Although, therefore, to the circular halos, and a vertical line making a cross with this ammonium-nitrate powder may be regarded as the first horizontal portion of the parhelic circle. successful advance towards the production of a comparatively Mr. John Lovell thus describes the phenomena observede smokeless artillery powder, it is not uniformly well adapted to Driffield :-"A splendid solar halo, with its attendant rarela the requirements which it should fulfil in naval service.

was observed this afternoon at 1.34 local time. The Attention was first seriously directed to the subject of smoke (diameter 45°) was almost perfect, the lower part only be less powder by the reports received about four years ago of slightly obliterated by the thick atmosphere near the horsen remarkable results stated to have been obtained in France with Attached to the upper side, an inverted portion of a similar hes such a powder for use with the magazine rifle (the Lebel) which appeared, brilliantly illumined on the concave side, the love was being adapted to military service. These reports were part giving out a dull red light. Again, 221" above this, as! speedily followed by others, descriptive of marvellous velocities also inverted, about 60° of arc beautifully coloured with the obtained with small charges of this powder, or some modifica- bow colours was clearly visible, the red side lowest. This ** tions of it, from gunz of very great length. As in the case of if it had been produced, would have circled the renith. To mélinite, the fabulously destructive effects of which were much mock lights on each side of the halo were drawn out into s vaunted at about the same time, the secret of the precise nature cones of intensely bright light, while the inner sky of the bak of the smokeless powder was so well preserved by the French was of a very dark shade. The most noteworthy featare all authorities, that surmises could only be made on the subject display was a brilliant patch of pure white light in the word even by those most conversant with these matters. It is now western sky, at a distance of 90' from the western moed well known, however, that more than one smokeless explosive and undoubtedly emanating from it, and which remained vele has succeeded the original powder, the perfection of which was for nearly ten minutes. The whole phenomena disappelied reported to be beyond dispute, and that the material now 2.8 p.m., the sky then being covered with streaky cirro-sena adopted for use in the Lebel rifle bears, at any rate, great haze from the north-north-west." similarity to preparations which have been made the subject of The patch of white light referred to by Mr, Lovell was dok patents in this country, and which are still experimental powders less produced by the junction of the perbelic circle with our in other countries.

the halos concentric with the sun. It is perhaps hardly see (To be continued.)

sary to note the relation that exists between halos and år

the

seratas clouds, and that the space included within the halo is verted circle was seen, the greater part of which was lost in the frequently of a more intense grey, or of a deeper blue than the blue of the sky above. The right-hand mock sun was fainter rost of the sky,

than the other, on account of the grey haze being more dense.” The son of Sir W. Herschel observed the phenomena at Mr. Buckton's observation is a demonstration of the principle Lielunt, and noted : "The sun was near the horizon. On laid down-namely, that parhelia always appear at the same kather side of it, at a distance of five or six diameters of the sun, elevation as the true sun, and are united to each other by a 32x a mock sun, not very bright, of the colours of the rainbow, white horizontal circle, whose pole is the zenith. This circle de mne on the right being the brighter. There was a scarcely changes in elevation with the true sun ; and the apparent semiperceptible rainbow, of which red was the only colour visible, diameter is always equal to the distance of the luminary from saning the two mock suns. This rainbow was brightest directly the zenith. Ater the sun. As far off again as the first was a second rainbow, Mr. Nagel, of Trinity College, Oxford, notes that :-"The ken, int fairly bright, which was equally visible from earth to solar halos on the afternoon of January 29 were very clearly arth. Vertically above the sun, a third, a very bright rainbow, seen in Oxford; the tangential arc to the outer halo' was exruched the second, being inverted, and having its centre straight tremely brilliant, and the two mock suns at the extremities of verhead. It did not look quite as large as the second. The the horizontal diameter of the inner halo were well marked. reather was clear, but the clouds on and above the horizon were During part of the time the halos lasted, a whitish incomplete Ka uniform grey colour, fading off gradually to a nearly clear circle was seen about 80° from the sun, and consequently beyond in overhead. There seemed always to be a much lighter shade the zenith. This circle seemed to correspond to that' first clouds where the sun and the two mnock suns described by Helvelius in 1661."

NIC.

It is evident from the descriptions given that the parhelia The coloared parhelia observed indicates the refraction and are not, as is sometimes supposed, images of the real sun at all, ks-persion of solar light by vertical prisms, whilst the phenomena but only the junctions of two of the circles formed. The upper

inverted arches are produced by the light which passes and the lower parts of these mock suns were drawn out and burragh horizontal crystals, at different azimuths.

connected with the first halo, whilst their sides were observed to Mr. Frank E. Lott, at Burton-on-Trent, observed a third be drawn out and to merge into the parhelic circle. phelia on the part of the first halo vertically above the sun, strilst Mr. H. G. Williams, of Caterham, observing the phenoacna about 4 p, m., noted that the sun appeared about 100 above ke horizon. So far, the observations of two or three parhelia THE INSTITUTION OF MECHANICAL sub two halos and two inverted arches agree with many former

ENGINEERS. Bescriptions. In the diagram appended, however, and in the mujority of sketches received, the inverted arch is not given as the arc of a circle, but hyperbolic.

of Mechanical Engineers took place on January 29, 30, Ne A. J. Batler, observing at Walton-on-Thames, remarks: and 31, in the theatre of the Institution of Civil Engineers. The byperbolic band above the sun was carefully noted ;" and The papers down for reading and discussion were as follows: Mr. C. A. Carus-Wilson, in the following observation made at on the compounding of locomotives burning petroleum resuse in Barnes, supports this view :

Russia, by Mr. Thomas Urquhart, Locomotive Superintendent, * The sun was just setting behind a bank of hazy mist, appear Grazi and Tsaritsin Railway, South-East Russia ; on the burning bg as a crimson disk enveloped in blue grey cloud; I first of colonial coal in the locomotives on the Cape Government boticed a distinct bow, of light grey tint, and coloured for a railways, by Mr. Michael Stephens, Locomotive Superin. Lart distance at its left extremity with the ordinary rainbow tendent; and on the mechanical appliances employed in the nis-red inside. There then appeared a part of a second manufacture and storage of oxygen, by Mr. Kenneth S. Murray, bow outside the other, coloured throughout the whole length of London. The latter paper was communicated through Mr. rabit-red inside. From the sun vertically upwards to the first Henry Chapman, we, there was a band of white light, quite distinct from the Mr. Urquhart's paper is one of a series of excellent and Light grey tint of the lower bow, and above the lower bow this thoroughly useful descriptions of work done by that gentleman and continued as a hyperbolic brush of white light: this brush on his railway, and had been for some time promised to the 12a much brighter and better defined than the vertical band. A Institution. In order to satisfy himself as to the utility and 12 y measurement, with a pocket sextant, of the angular radii of saving of fuel in compound locomotives, he obtained the ke two tuws, gave 46° and 23' for the outside and inside bɔws sanction of the Government for altering one locomotive by way impedively."

of experiment. The altered engine was put to work, and the Ms

, il. w. Pyddoke also remarks :-" The most noticeable driver was allowed over a month's running to get fully acung of all was the shape of the upper bow, which was like a quainted with the handling in regular service. Comparative bytherbole except at its ends where it bent round again very trials were then made of the compound against a non-comhtly;" and other correspondents concur in this description | pound locomotive with the same weight of train, on the if the shape of the first inverted arch.

same days, so as to expose them both to the same circumFrom the descriptions and figures given it is evident that the 'stances in regard to weather. It was clearly proved that the wo parhelia on the parhelic circle are the respective centres of compound burnt 22 per cent. less of the petroleum refuse lalua similar to the first halo concentric with the real sun ; the used as fuel than the non-compound engine, and the author's ntersection of these two circles with that surrounding the sun experience has left no doubt in his own mind that compound rives the appearance of a hyperbolic curve at the top of it. An locomotives are the engines of the future in all countries. Mr. sactly similar appearance was drawn by Pastorff as occurring on Urquhart's results are thoroughly borne out by those obtained December 29, 1789, and is found in his “Beobachtungen der in this country by Messrs. Worsdell and Webb. Some engianenitecke", and L'Astronomie for August 1889 contains a neers suppose that this great economy in fuel is due to the drawing and description of a very similar appearance.

higher working steam pressure, and therefore greater expansion Lanar halos followed the solar halos on the 29th ult., and in the compound engines as compared with the non-compound a the following day Mr. G. B. Buckton, F.R.S., observed engines. bree ine parhelia and a halo at Ilaslemere, and describes The paper by Mr. Michael Stephens is a description of the them as follows :

South African coal-fields, their discovery, and general working "The sun shone brightly, but through a moderate haze. On within the last sixteen years. It appears from the paper that ile nght and ou the left, at equal altitudes with the sun, an the local coal cannot be burned to advantage without a special stilong bright patch of light appeared. That on the left was the arrangement of fire-bars—as may be well imagined, since it beghtest

, and formed a blurred image of the sun with all the contains nearly 30 per cent of incombustible matter. pristnatic colours of the rainbow, but the colours were reversed Mr. Kenneth S. Murray gives an interesting account of the in order. The upper and lower parts of these mock suns were commercial preparation of oxygen from the atmosphere by trawn out, and formed portions of a large circle of about (by eye means of the alternate heating and cooling of the monoxide of er imate) zoo radius. These images were connected with the barium. About thirty years ago the eminent French chemist have, but a lower stratum of finely striated cloud came between Boussingault made the discovery that, at a temperature of about the eye and these patches. Immediately above the true sun a 1000° F., the monoxide of barium would absorb oxygen readily third patch of light occurred, througti which a portion of an in- from the atmosphere, with the resulting formation of the dioxide;

and that at a higher temperature of about 1700° F, the oxygen the thirteen races which he proposes for his classification, adders thus absorbed would be given off again, and the monoxide would separate remarks on the varieties of each. The dog, by 1.6 apparently be restored to its original condition. The paper de Mortiliet. Assuming from negative evidence them clearly describes the machinery required for the manufacture of existence of the dog in the Quaternary age, the author traces de oxygen by means of barium oxide.

presence onwards from the Kjokkenmoddings, in when abundant remains of this animal are to be found. Pasing the

the prehistoric ages in Europe he considers at length the existe UNIVERSITY AND EDUCATIONAL

that can be advanced of the existence of several vanetirs de INTELLIGENCE.

dog among the Egyptians, and later on among the soos OXFORD.-The lecture lists for this term include the following Greeks and Romans; and in the fact of the innamento courses :-Prof. Clifton, Magnetism, Mr. Baynes, Thermo varieties of Canis domesticus, M. de Mortillet believes we dynamics ; Prof. Odling, Diacidic Olefine Acids ; Mr. Veley, one of the most conclusive proofs of evolution. -Observale Physical Chemistry. Prof. Burdon-Sanderson has resumed his on the skeletons of two young orangs, by M. Herve - Pu lectures, and Mr. Gotch is treating of the Physiology of Muscle. Columbian ethnography of Venezuela, by Dr. Marcano, TV Dr. Tylor lectures on the Development of Religions.

most interesting report in this treatise is that referring te An open Fellowship in Mathematics at Christ Church has Grotto de Cerro de Luna, owing to the almost absolute ceramy been awarded to Mr. C. H. Thompson, Queen's College, Lec. that it had never been entered since Guiana was first visited turer in Mathematics at Lampeter. No other mathematical

white men. Here Dr. Marcano recovered fifty two ask. Fellowship has been awarded for about seven years.

forty-three female skulls, with five of children, together it The arrangement of the Pitt-Rivers anthropological collection numerous long bones. Among these skulls many were pre at the Museum is proceeding as rapidly as the constant acqui- red, and others had obviously been embalmed. The gears sition of new material allows, and a large portion of the collec- mean of their cephalic index was 79, while the facua tion is now open for public inspection.

characters were mesorrhinic and prognathic. -On correlaire

variations in the biceps, by M, G. Hervé-A report of CAMBRIDGE.--At the next meeting of the Cambridge Philo. Seventh Conference on Transformism, by M. M. Duval

. The sophical Society, on Monday, February 10, the following papers author here gives an interesting biographical notice of the grea will be read :

French savant Lamarck, entering at the same time fally in (1) W. Bateson (St. John's), on the perceptions and modes of the character and scope of his researches, and showing how far feeding of fishes.

his views differed from, or approximated to, those of Darer (2) A. C. Seward (St. John's), notes on Lomatophloios. As a résumé of what Lamarck attempted on the same line 1

(3) S. F. Harmer (King's), on the origin of the embryos in inquiry so successfully followed by. Darwin, M. Duval's reper the ovicells of Cyclostomatous Polyzoa.

presents much interest for the English reader.On the mehr Prof. Stuart has communicated to the Vice-Chancellor his of Morbihan, by M. Gaillard. - On the discovery of Rates intention of resigning the Chair of Mechanism and Applied hausian fint implements near Macon, by M. Lafay.-CompeScience before the end of the current academical year.

son of three sub-species of man, by M. Lombard.

SCIENTIFIC SERIALS.

SOCIETIES AND ACADEMIES. American Journal of Mathematics, vol. xii., No. 2 (Baltimore, January 1890). —The number opens with the concluding

LONDON. part of Mr. Forsyth's paper on “Systems of Ternariants that Royal Society, January 23.—"On a Photographic Meibo are Algebraically Complete" (pp. 115-160). It is illustrated for determining Variability in Stars." By Isaac Robert with numerous tables and closed with a useful abstract of con F.R.A.S. Communicated by Prof. J. Norman Lockya tents.- In the following memoir (pp. 161-190), by Prof. Franklin,

F.R.S. on “Some Applications of Circular Co-ordinates," the author Some of the uncertainties which necessarily attend the investigates, with the aid of these co-ordinates, some interesting termination of variability in the brightness of stars by ere theorems relating to the orientation of systems of lines given observations are removed by the application of photographic in a recent volume (vol. x. p. 258) by M. Humbert. Several methods, and particularly by that of giving two or more es further illastrations are given, and the memoir closes with a posures of the same photographic plate to a given sky space discussion of the curve given by the equation sin xdx = sin ydy.-- with intervals of days or weeks between each exposure. Mr. F. N. Cole writes (pp. 191-212) on “Rotations in Space In this way any errors caused by atmospheric, actinic. of Four Dimensions." The present article is preliminary to a chemical changes, together with those due to personal bius second paper on groups of rotations in four-dimensional space eliminated, and the study of stellar variabiliiy can be parnese which is to follow.

under conditions that admit of the necessary exactitude. Bulletins de la Société d'Anthropologie, tome xii., serie iii., method, the enlargement on paper from the negative is

As an illustration of the applicability of this dual photographer fasc. 3 (Paris, 1889). --Continuation of M. Dumont's paper ou submitted. It shows the results obtained by two exposure the natality of Paimpol, in which he treats at great length of the the same plate to the sky in the region of the great nebals causes which influence the ratio of marriages contracted in every hundred of the population in the maritime districts of Brittany,

Orion. The first exposure was of two hours' duration and of the number of children born in each family. In both these January 29, and the second of two and a half house respects the means rank amongst the lowest for all France. February 3, 1889. The stellar images formed during the One cause for this may be the preponderance of women over two exposures are 00122 of an inch apart, measured from entre men, a large number of the latter being engaged as seamen, or

to centre, and therefore comparable with each other in the lis taking part in the Iceland and other distant fisheries. Another

of a microscope. When the images are examined in factor in this problem is probably the subdivision of property among

manner thus indicated, and their diameters als measarel all the members of a family, who in the peasant and small

means of a suitably made eye-piece micrometer, it is found the burgher classes, not uncommonly remain together all their lives,

at least ten of the photographed stars, the magnitudes of whiru and avoid marriage in the fear of diminishing their individual

are estimated to range between the 7th and 15th, have changed shares of the patrimony. This, coupled with the repugnance,

to a considerable extent in the short interval of five days. so common among the French peasantry, against large families,

The ten stars referred to are to be found within an area of lan leads indirectly to late marriages or to celibacy, and has thus

than two square degrees of the sky, and in the table given exercised a baneful influence on the normal increase of the

the co-ordinates of their positions with reference i Onkis. population.--An essay on the classification of human races,

The measurements of the diameters of their photo-images based entirely on physical characters, by M. Denniker. Believe

scale of o'oooo2 of an inch are also given. ing in the long persistence of types in spite of the constant inter "Physical Properties of Nickel Steel." By J. Hopkinik mixture of races, the author thinks that it is only by a careful D.Sc., F.R.S. study of the typical characteristics in a so-called ethnic group Mr. Riley, of the Steel Company of Scotland, huku that we can arrive at any correct idea of the affinities between sent me samples of wire drawn from the material concerning as different races. In an elaborate synoptical table he enumerates magnetic properties of which I recently made a communicare

the Royal Society. As already stated, this material contains was then allowed to return to the temperature of the room, and per cent of nickel and about 74 per cent. of iron, and over was subsequently heated, the actual observations being shown arge of temperature from something below freezing to 580° C. by crosses on the lower branch of the curve ; the heating was han exist in iwo states, magnetic and non-magnetic.

continued to a temperature of 680° C., and the metal was then The wire as sent to me was magnetizable as tested by means allowed to cool, the actual observations being still shown by a magner in the ordinary way. On heating it to a dull red crosses. From this curve, it will be seen that in the two states

it became non-magnetizable, whether it was cooled slowly of the metal, magnetizable and non-magnetizable, the resistexceedingly rapidly by plunging it into water. A quantity ances at ordinary temperatures are quite different. The specific the wire was brought into the non-magnetizable state by resistance in the magnetizable condition is about o'000052, in aling it, and allowing it to cool. The electric resistance of a the non-magnetizable condition it is about 0'000072. The curve stion of this wire, about 5 metres in length, was ascertained of resistance in terms of the temperature of the material in the terms of the temperature ; it was first of all tried at the magnetizable condition has a close resemblance to that of soft diaary temperature, and at temperatures up to 340°C. The iron, excepting that the coefficient of variation is much smaller, canic resistances at these temperatures are indicated in the as, indeed, one would expect it to be in the case of an alloy ; me by the numbers 1, 2, 3. The wire was then cooled by at 20° C. the coefficient is about 0.00132, just below 600° C. it sans of solid carbonic acid; the supposed course of change of is about 0.0040, and above 600° it has fallen to a value less than stance is indicated by the dotted line on the curve ; the actual that which it had at 20° C. The change in electrical resistance ervations of resistance, however, are indicated by the crosses effected by cooling is almost as remarkable as the change in the the neighbourhood of the letter A on the curve. The wire magnetic properties.

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wamples of the wire were next tested in Prof. Kennedy's ' 1889, in company with Mr. James Eccles, to whom the author is Wcralory for mechanical strength. Five samples of the wire deeply indebted for invaluable help. The paper deals with the ere taken which bad been heated and were in the non-mag. following subjects :-(1) The Andermatt Section. By the geoes zable sate, and five which had been cooled and were in the logists aforesaid, a highly crystalline white marble which occurs

petizable state. There was a marked difference in the on the northern side of the Urserenthal trough, at and above plness of these two samples; the non-magnetizable was ex Altkirch, near Andermatt, is referred to the Jurassic series emely soft, and the magnetizable tolerably hard. Of the five non (members of which undoubtedly occur at no great distance, bagnetizable samples the highest breaking stress was 50'52 tons almost on the same line of strike). The author describes the kes equare inch, the low e-t 48-75; the greatest extension was 33-3 relation of the marble to an adjacent black schistose slate, and esetat., the lowest 30 per cent of the magnetizable samples, discusses the significance of some markings in the former which e highest breaking stress was 88'12 tons per square inch, the might readily be considered as organic, but to which he assigns met was 8576; the highest extension was 8.33, the lowest a different origin. He shows that there are most serious 70. The broken fragments, both of the wire which had difficulties in regarding these two rocks as members of the same ngmally been magnetizable and that which had been non series, and explains the apparent sequence as the result of a ngnetizable, were now found to be magnetizable. If this sharp and probably broken infold, as in the case of the admitted maserial could be produced at a lower cost, these facts would band of Carboniferous rock at Andermatt itself. That the secaxe a very important bearing. As a mild steel the non-mag tion is a difficult one on any hypothesis the author admits, but petizable material is very fine, baving so high a breaking stress in regard to the former of these, after a discussion of the

so great an elongation at rupture. Suppose it were used for evidence, he concludes, “that tendered on the spot demands a sy purpose for which a mild steel is suitable on account of this verdict of 'not proven '—that obtainable in other parts of the onsiderable elongation at rupture, if exposed to a sharp frost Alps, will compel us to add, 'not provable.' (2) 'The Schists is properties would be completely changed—it would become of the Val Piora. These schists, already noticed by the author sentially a bard steel, and it would remain a hard steel until in his Presidential address to the Society in 1886, occur in force 1 hai been beated 10 a temperature of about 600° C.

near the Lago di Ritom, and consist of two groups—the one

dark mica-schists,sometimes containing conspicuous black Geological Society, January 22.-W. T. Blanford, F.R.S., garnets, banded with quartzites, the other various calc-mica l'resident, in the chair. --The following communication was schists; between them, apparently not very persistent, occurs mosi:- On the crystalline schists and their relation to the Meso a schist containing rather large staurolites or kyanites. On Punk rocks in the Lepontine Alps, by Prof. T. G. Bonney, the north side is a prolongation of the garnet-actinolite

R.s. In the debate upon the paper on two traverses of the (Tremola-) schists of the St. Gothard and then gneiss, cryslalline rocks of the Alps (read December 5, 1888) it was on the south side gneiss. There is also some rauchwacké. oduled that rocks had been asserted on good authority to exist in This rock, at first sight, appears to underlie the Piora Be Lepontine Alps, which contained Mesozoic fossils, together schists, and thus to be the lowest member of a trough. If al gamets, staurolites, &c., and thus were undistinguishable so, as it is admittedly about Triassic in age, the Piora schists. from crystalline schists regarded by the author as belonging to would be Mesozoic. The author shows that (1) the latter rocks che presumably Archaean massifs of that mountain-chain. In do not form a simple fold ; (2) they are, beyond all question, Teply the author stated that he regarded this as a challenge to demonstrate the soundness or unsoundness of the hypothesis to

altered sediments; (3) they have often been greatly crushed

subsequent to mineralization ; (4) the garnets, staurolites, sbich he had committed himself. The present paper gives the &c. (if not injured by subsequent crushing) are well deresult of his investigaticos, undertaken in the month of July veloped and characteristic, and are authigenous minerals. See Add.ess to the Institution of Electrical Engineers (Nature, January

(3) The Rauchwacké and its Relation to the Schist. (a) The Val Bil

Piora Sections : The author shows that the rauchwacké, which

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