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is not really much more difficult than the dressing of a of sunlight, condensed by a lens, through the flame of a child for church. The most remarkable part of the candle. I noticed that where the cone of rays cut the process is the painting of the forehead, trunk, and ears, luminous envelope there were two patches of light brighter which follows a thorough washing. “The designs are than the general flame, which were evidently due to sunoften good, and the whole serai, excepting always the light scattered by matter in the envelope which was in a elephant himself, is deeply interested. His mind and state of suspension. The patches corresponded in area trunk wander; he trifles with the colour-pots; so with to the intersection of the double cone by the envelope, each stroke comes an order to stand still. Some mahouts and their thickness was, I may say, insensibly small. are quite skilful in this pattern work."

Within the envelope, as well as outside, there was none In an interesting chapter on the training of animals, of this scattering. The patches were made more conMr. Kipling shows that the skill of the natives of India spicuous by viewing the whole through a cell with an in this difficult art bas often been greatly overrated. The ammoniacal solution of a salt of copper, or through a Oriental brings "boundless patience” to the task, but blue glass coloured by cobalt. In the former case the "he has no steadfastness of aim, nor has he sufficient light from the flame was more weakened than the scattered firmness of hand and will to secure confidence and light, which was richer in rays of high refrangibility ; in obedience.” The cheetah or hunting leopard (Felis the latter case the patches were distinguished by a jubatay, when caught and tamed, undergoes so little difference of colour, the patches being blue, while the training in the field that it loses its natural dash, and is fame with a suitable thickness of blue glass was purplish. often left behind by the antelope. It becomes so mild The light of the patches exhibited the polarization of

light scattered by fine particles-that is to say, when viewed in a direction perpendicular to the incident light it was polarized in a plane passing through the beam and the line of sight.

When the beam was passed through the blue base of the flame there was no scattered light. Aluminous gas flame showed the patches indicating scattered light like the flame of a candle, but less copiously. They were not seen in a Bunsen flame or in the flame of alcohol, but were well seen in the luminous flame of ether. When a glass jar was inverted over burning ether, the blue parl, which does not show scattered light, extended higher, till, just before the fame went out, the luminous part disappeared altogether. A Bunsen fame, fed with chloride of sodium, did not show the phenomenon, though the flame was fairly luminous.

The phenomenon shows very prettily the

separation of carbon (associated, it may be,

UK
Fig. 4.-A restless bedfellow.

with some hydrogen) in the flame, and at
the same time the extreme thinness of the layer

which this forms. It shows, too, the mode of that it is frequently allowed to curl itself under the same separation of the carbon-namely, that it is due to the blanket with its keeper. The keeper, when his bedfellow action of heat on the volatile hydrocarbon or vapour of is restless, "lazily stretches out an arm from his end of 'ether, as the case may be. At the base, where there is a the cot, and dangles a tassel over the animal's head, plentiful supply of oxygen, the molecules are burned at which seems to soothe him.” In the early morning Mr. once. Higher up the heated products of combustion have Kipling has seen a cheetah “sitting up on his couch, a time to decompose the combustible vapour before it gets red blanket half covering him, his tasselled red hood oxygen enough to burn it. In the ether just going out, pushed awry, looking exactly like an elderly gentleman for want of fresh air, the previous decomposition does in a nightcap, as he yawned with the irresolute air of one not take place, probably because the heat arising from who is in doubt whether he will rise or turn in for yet the combustion is divided between a large quantity of another nap.” This is mentioned as an instance of the inert gas (nitrogen and products of combustion, and the curious intimacy that exists in India between animals combustible vapour, so that the portion which goes to and those who have charge of them.

the latter is not sufficient to decompose it prior to comOf the remaining chapters we can only say that all of bustion. them embody the results of a close study of the animal In the Bunsen flame fed with chloride of sodium, the world and of the Hindu character. We may note as of absence of scattered light tallies with the testimony of especial interest the three concluding chapters, on animals the prism, that the sodium is in the state of vapour, though in Indian art, on beast fights, and on animals and the I would not insist on this proof, as it is possible that the supernatural.

test of scattering sunlight is not sufficiently delicate to show the presence of so small a quantity of matter in a

solid or liquid state.-Yours sincerely, ON AN OPTICAL PROOF OF THE EXISTENCE

G. G. STOKES. OF SUSPENDED MATTER IN FLAMES.1 EAR PROFESSOR TAIT,- I write to put on paper

P.S.-I fancy the thinness of the stratum of glowing

carbon is due to its being attacked on both sides-on the an account of the observation I mentioned to you to-night, in case you should think it worth communicat

outside by oxygen, on the inside by carbonic acid, which ing to the Royal Society of Edinburgh.

with the glowing carbon would form carbonic oxide. In the course of last summer I was led, in connection [When the above was written, I was not acquainted with with some questions about lighthouses, to pass a beam the previous paper by Mr. Burch, published in vol. xxxi. ! Read before the Royal Society of Edinburgh on June 15, 1891. Re

of NATURE (p. 272), nor did any of the scientific friends to printed from the Proceedings of the Society.

whom I had mentioned the observation seem to be aware

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of it. Had I known of it, I should not have thought my chemistry, geology, mineralogy, animal physiology, botany, paper worthy of being presented to the Royal Society of the principles of mining, navigation and nautical astronomy, Edinburgh, as Mr. Burch has anticipated me in the steam, the principles of agriculture, and hygiene. fundamental method of observation.

Mrs. R. M. CRAWSHAY, writing to us from Mentone, on The reaction mentioned in the postscript is to be taken merely as a specimen of the reactions, on the inside of December 2, about the recent eclipse of the moon, refers to the the carbon stratum, by which the carbon may be re

fact that “the Rev, A. Freeman and Mr. R. T. Leslie are not engaged in a gaseous combination. Carbonic oxide is agreed as to the shadow on the moon's disk having colours or only one of the combustible gases, not originally present, not.” For some time there were illuminations and fireworks which are formed during the process of combustion, and at Monte Carlo on account of the birthday of the Prince of are found inside the envelope in which the combustion is Monaco, and, when these were over, clouds suddenly came up. going on.-G. G. S., November 20, 1891.]

" It was only,” Mrs. Crawshay says, " when the moon was very nearly half obscured that I caught a glimpse of her without any

colouring whatever, orange or otherwise. One could only liken NOTES.

it to a painting in Indian ink." The annual general meeting of the Institution of Electrical MR. GEORGE T. Bettany, who was well-known as a popular Engineers will be held at the Institution of Civil Engineers, writer on scientific subjects, died on December 2 in his forty25 Great George Street, Westminster, this evening (Thursday), second year. For some years he lectured on botany at Guy's at 8 o'clock, for the reception of the annual report of the Hospital. Conjointly with Prof. Parker, he wrote a work on Council, and for the election of Council and officers for the year “The Morphology of the Skull.” He was also the author of 1892. The following paper will be read :-"On the Specifica- “ The World's Inhabitants," and other books. For Messrs. tion of Insulated Conductors for Electric Lighting and other Ward, Lock, and Co., he edited “Science Primers for the purposes," by W. H. Preece, F.R.S., Past-President.

People" and "The Minerva Library.” The Royal Danish Academy of Sciences at Copenhagen An interesting paper on aluminium and its application to offers two prizes of 400 and 600 kronen respectively, for investi- photography, by Mr. G. L. Addenbrooke, is printed in the gations on the exact nature and proportions of the more im- December number of the Journal of the Camera Club. Mr. portant carbo-hydrates present, at different stages of malurity, Addenbrooke thinks aluminium ought now to supersede brass in the cereals in most general use ; and for investigations on the for photographic lenses and the metal parts of cameras. By its Phytoptus galls found in Denmark, with a monograph on the use the weight of lenses, Aanges, and adapture is reduced nearly insects producing them. The prizes are to be awarded in to one-third. He is also in savour of aluminium being used for October 1893

the revolving tripod heads fixed in the bare boards of cameras,

as these are rather too heavy in brass. “In band-cameras," he An improved armillary sphere has been patented by Prof. J. says, “I think the metal should be useful in most places where S. Slater, of Calcutta University, which differs from other

there are metal parts. I am also not without hopes that dark spheres of the same kind in having a latitude circle to which the celestial sphere is hinged, and in being provided with a more compact than the wooden ones.

slides may be made in it altogether, which will be lighter and movable horizon which adjusts itself to the selected latitude. It

For developing-dishes, can be obtained from Messrs. Walsh, Lovett, and Co., Philpot used in photography is very slight on it, and when there is any,

also, it is very suitable, as the action of most of the chemicals Lane, E.C.

the compounds formed would not be harmful.” The next one-man photographic exhibition organized by the

In his latest communication to the American Journal of Camera Club will consist of pictures by Mr. J. Pattison Gibson,

Science (for November), Prof. Goodale describes his visit to the of Hexham. It will be opened in connection with a concert to

Queensland Museum at Brisbane, under the charge of Mr. be held on the first Monday in January, 1892.

De Vis, rich in specimens illustrating the natural history and With the consent of the Sultan of Muscat, the Survey of ethnology of the colony. An account is also given of the India is about to establish a tidal observatory at Muscat. This well-known Botanic Garden and Laboratories at Buitenzorg in will probably be followed by the establishment of another Java, under the directorship of Dr. Treub, and of the annex on observatory of the same kind at Bushire in the Persian Gulf. a contiguous mountain ; of the Botanic Garden and Experi

mental Garden at Singapore, under the control of Mr. Ridley; We have had some correspondence with Prof. Arnold about

and of the new and at present but poorly developed Botanic our notice of his speech at the recent meeting of the Institution Garden at Saigon in French China. of Mechanical Engineers. Referring to his remarks on Prof. Roberts-Austen's “Report to the Alloys Research Committee,”

POISONING by mussels is a well-known fact. Such poisoning we expressed the opinion that it was rather straining the pre

appears in chronic form in Tierra del Fuego, mussels being rogative of rhetoric to speak of the work done by Prof. Roberts

abundant on the shores, and other kinds of food rare, so that the Austen as “not worth a rush." We did not intend to imply natives eat large quantities of the former daily, both of bad that Prof. Arnold applied the expression "not worth a rush" to

and of good quality. According to a doctor of the Argentine the whole of the work on which Prof. Roberts-Austen reported. fleet, M. Segers, the mussels are rarely injurious at their He wishes us to state that what he said was, that he ihought maximum time of growth, which corresponds with full moon, but 'any analogue obtained from a comparison of simple bodies

when the moon wanes, they become poor and often poisonous. like gold and lead with a complex body like steel would not be

The poisonous quality apparently results from the death of a worth a rush."

large number at this time, and the putrefaction of their bodies

yielding ptomaïnes which are absorbed by the surviving mollusks. The reports of the examiners on the results of the science In any case, the Fuegians are often attacked by a liver comexaminations held in April and May 1891 have been issued. plaint, consisting in atrophy of the organ, with jaundiced colour The examinations related to building construction, naval arcbi. of the skin and tendency to hæmorrhage ; and M. Segers tecture, mathematics, theoretical mechanics, applied mechanics, believes this is due to mussel poisoning. He finds sulphate of magnetism and electricity and alternative elementary physics, atropine an efficacious antidote.

PRINCIPAL J. L THOMPSON, of the Hawkesbury Agricultural ledge it would, he thinks, be presumptuous to class Notoryctes College, New South Wales, has no doubt that the climate and among the Monotremes proper, although several leading much of the soil of Asstralia are well suited for the culture of naturalists incline to the opinion that its affinities are closer to the olive. All that is needed, he thinks, is an adequate supply these mammals than to the Marsupials. He prefers for the of labour. He himself has been very successful in preserving present to look upon it as an aberrant Polyprotodont. green olives; and in a paper on the subject in the August oumber of the Agricultura: Gazette of New South Wales he gives the Journal which is to contain, among other things, contributions

The Institute of Jamaica has isued the first number of a following account of the sysłem adopted. The olives are very regarding newly discovered flora and fauna of the island, and carefully picked from the trees when about full grown, but perfectly green. They should be handled like eggs. If they are articles dealing with botany and kindred sciences. Foar braised in any way, they will become black and decompose. In parts will be published in the year. In this first number there the green state, olives contain gallic acid, which gives them an are excellent notes, by Mr. T. D. A. Cockerell, on the transacrid taste. To remove this they are first of all steeped in alkaline formation of some Jamaica Lepidoptera

. He points out

that, water, made either of wood ashes, lime water, or washing soda ; although many species of butterflies and moths have been of the latter, aboat three or foar ounces to the gallon of water. described from Jamaica, the transformations of very few are

known. As soon as the lye has penetrated through the pulp, which is usually in from eight to ten hours, they are put into clean water DR. A. H. Post, the well-known anthropologist, describing and steeped until all acrid and alkaline taste has been removed. in this week's Globus various marriage customs, refers to a During that time the water is changed every day. They are then strange sort of symbolical marriage which is supposed to have put into brine, composed of one pound of salt to each gallon of originated in India. It is a marriage with trees, plants water, and kept carefally covered with a thick linen cloth, for if animals, or inanimate objects. If anyone proposes to enter exposed to the air they will turn black. They are finally put upon a union which is not in accordance with traditional ideas, up in air-tight jars.

it is believed that the ill-lack which is sure to follow may be The Meteorological Department of the Government of India iaverted by a marriage of this kind, the evil consequences being has published Part IV. of “Cyclone Memoirs,” being an inquiry borne by the object chosen. In various regions a girl must not into the nature and course of storms in the Arabian Sea, and a marry before her elder sisters, but in some parts of Southern catalogue and brief tistory of all recorded cyclones in that sea India the difficulty is overcome by the eldest daughter marrying from 1648 to 1889. The work, which has been prepared by the branch of a tree. Then the wedding of the second daughter Mr. W. L. Dallas, chiefly for the use of mariners navigating may safely be celebrated. Dr. Post gives several other instances, those paris, will no doubt be of considerable use to them, as which are likely to be new 10 many students of anthropology. hitherto there were no track charts of the storms in the Arabian ACCORDING to an official French Report, the copper mines of Sea for the different months. For the majority of the storms French Congo are likely to prove of considerable importance. quoted the available materials are admittedly very scanty ; They lie in the district around the sources of the Ludima-Niadi, severtheless, the author has been able to draw some useful con about two days' journey south of Siéphanieville. The ore is clusions from them, with reference to the general behaviour of malachite, which is brought 10 the surface by about 350 negroes. the storms. The paper is divided into two parts—the first gives Their methods of wuk are extremely simple. They reach the the details of each of fifty-four storms in chronological order, malachite by digging out, with implements of hard wood, holes the second treats of their geographical distribution and move or shafts three feet wide and twice as deep. The malachite is ments according to months and seasons, and the discussion is broken on the ground, and afterwards, when pulverized, put followed by charts showing the tracks of the storms in the into a furnace on a tray with charcoal, on which bellows are different months. The cyclones are formed on the northern made to play. In due time the tray is removed by means of limits of the south-west monsoon ; when the northern limits of pieces of bamboo, and the metal is poured into sand moulds. the monsoon reach the land, and also when the north-east The entire district is said to be rich in copper, and masses of monsoon extends from Asia to the equator, which is the case malachite are frequently found in the Ludima. from December to March, no cyclones are formed over the Arabian Sea. The barometric fall is gradual and equal on all

MR. ERNEST E. THOMPSON, of Toronto, contributes to the new sides, except near the centre, and a depression of o-25 inch volume of the Proceedings of the U.S. National Museum (vol. below the average is indicative of the existence of a cyclone in xiii.) a valuable study of the birds of Manitoba. He gives an enthe neighbourhood. When the storms are in confined waters thusiastic description of the music of prairie larks, large numbers they may burst with great suddenness, but in other cases strong of which, at dawn, may be beard in the spring to "burst all together wiods are felt for several hundred miles around the centre. The into a splendid explosion of song, pouring out their rich, strong northern parts of the Arabian Sea are liable, during the pre- voices from every little height and perch, singing with all their valence of the north-east monsoon, to be disturbed by small might.” They sing all day, and at night joyously hail the moon. cyclonic storms descending from the highlands of Persia and As their notes become more complicated, the most casual Beluchistan, but the whole of the south-west of the Arabian Sea, observer cannot fail to perceive “that the love-fires are kindling, thoagh liable to south-west gales during the summer monsoon,

and that each musician is striving to the utmost of his powers to and to strong north-east winds during the winter monsoon, is surpass all rivals and win the lady lark of his choice.” “On free from cyclones.

one occasion,” says Mr. Thompson, “as I lay in hiding near a DR. STIRLING's Notoryctes typhlops, the lately discovered fence, three larks came skimming over the plain. They alighted

within a few yards of me, and two of them burst into song, Australian animal, to which we have repeatedly called attention, sometimes singing together and sometimes alternately, but the forms the subject of an interesting note in the “Hand List of third was silent. When at last they flew up, I noticed that the Australian Mammals,” hy J. Douglas Ogilby, an advance copy silent one and one of the singers kept together. I had been of a portion of which has been forwarded to us. The con.

witness to a musical tournament, and the victor had won his clusion at which Mr. Ogilby has arrived, after an exhaustive

bride." study of Dr. Stirling's pamphlet, is that in this ani nal we have at last obtained a definite connecting link between the Mono. ANOTHER of the many birds of Manitoba about which Mr. tremes and the Marsupials. At the present stage of our know.' Thompson has something interesting to say is the crane. The first intimation of its adveat in the spring is usually a loud decorated, and some in very odd shapes, and several specimens trumpeting or croaking that seems to shake the air for miles. of a big stone wheel, and a stone cylinder fitting into it, But the cranes themselves, generally in pairs, soon begin to be probably used for some sort of game. The mounds contain seen. Their food at that season is chiefly rose-pips, in houses, and, as usual, most of the relics are found near the gathering which they stalk over the bare plains. At first little can dead bodies, which are always buried under the floor, partly be noted but their excessive wariness, but as the warmer weather under the wall. These people must have been there before the quickens their feeling, they often “so far forget their dignity arrival of the cave and cliff dwellers, but who they were it as to wheel about and dance, Alapping their wings and shouting would not yet be safe to say. as they 'honour their partners,' and in various ways contrive

MESSRS. T. COOKE AND Sons, of Buckingham Works, to exhibit an extraordinary combination of awkwardness and agility.” This dance Mr. Thompson has seen ouly during the York, have issued a new illustrated catalogue of telescopes, pairing season.

surveying and other optical instruments. REFERRING to the question

MESSRS. GURNEY AND JACKSON (Mr. Van Voorst's succes" whether squirrels are torpid in winter,” Mr. C. Fitzgerald writes in the December number of the sors) hope to have ready for publication by the end of this year

the first volume of “A Synonymic Catalogue of LepidopteraZoologist that, during many winters pa-sed in the backwoods of

Heterocera," which Mr. W. F. Kirby, of the Zoological DepartNorth America, he has seen squirrels frisking among the trees in the coldest weather. On bright sunny days especially they delight

ment, British Museum, has been for some time engaged upon. in chasing tach other from tree to tree among the evergreens, and SIR J. D. Hooker's well-known book of travels, “ Himalayan cover the snow with their tracks. The young of the ordinary Journals,” has been reprinted in the Minerva Library series red squirrel are born early in the spring. The “Chipmunks," (Ward, Lock, Bowden, and Co.). It is reprinted from the first or little striped ground squirrels, lay up in the autumn a store (unabridged) edition, with the omission of some of the apof provisions o? grains, nuis, &c., for winter, and on fine days pendices, which were only of limited general interest. Mr. may be seen sunning themselves. Mr. Fitzgerald has on several Murray has supplied copies of the original woodcuts, many of occasions come across their hoards, and once saw two large them from drawings by the author. bucketssul of shelled buckwheat taken from the hollow of an old birch tree that the woodmen had chopped down on the edge of

A New Review, which will be partly scientific, is about to be a clearing which had been cropped the previous summer with

issued at Rome. It is to be published twice in the month, and

will be entitled Natura ed Arte. that grain.

The admirable Harveian Oration recently delivered by Dr. W. At the meeting of the Linnean Society of New South Wales

H. Dickinson has just been published by Messrs. Longmans, on October 28, the fifth part of Mr. E. Meyrick's “ Revisiɔn of

Green, and Co. Australian Lepidoptera” was read. This paper practically concludes ibe Australian Geometrina, except in so far as future PART 9 of Cassell and Co.'s “ Universal Atlas " has just been discoveries may produce fresh material. One hundred and issued. It contains a map of the Balkan Peninsula, another of twelve species are included, of which forty-seven are described China and Japan, and one of Japan alone, the first occupying

a double page. MR. Carl LUMHOLTZ contributes to the cursent Bulletin of Two communications upon phosphides of boron have been the American Geographical Society a very interesting report on published by M. Moissan and M. Besson respectively in the his explorations in Northern Mexico. The most remarkable most recent numbers of the Comples rendus. M. Moissan has caves he met with were at the head of the Piedras Verdes River, obtained two compounds of phosphorui and boron of the com6850 feet ahove sea-level. These caves contain groups of position PB and P,B5, by the reduction of the new compound deserted houses or small villages, and the houses are splendidly PBI, recently prepared by him (comp. NATURE, vol. xlv. p. 67) made of porphyry pulp, and show that the inhabitants had in a current of hydrogen gas. M. Besson, however, in July of attained a comparatively high culture. The dwellings were this year published a note upon one of these compounds, PB, sometimes three stories in height, with small windows, and which he obtained by heating the compound BBrg.PH, to the doors made in the form of a cross ; and occasionally there were temperature of 300° C , and in the current number of the Comptes stone staircases. The caves, which number about listy in a rendus calls M. Moissan's attention to the fact. The e comstretch of twenty miles, are from 100 to 200 feet above the pounds of boron and phosphorus appear to be somewhat rebottom of the cañon, and the largest is some fifty feet high. markable substances, and the following is a brief account of One series of them, on the shady side of the cañon, had been their mode of preparation and properties, as described by Messrs. reserved for burial-places. Here, at a depth of three feet, Mr. Moissan and Besson. The curious compound PBI, is a substance Lumholtz dug out a number of bodies in a wondersul state of crystallizing in vacuo in beautiful bright red crystals. When preservation, the salt petre which is mixed with the disintegrated These crystals are heated in a current of dry hydrogen to a temrock having for centuries preserved them, making them look perature of 450°-500°, three things happen : a small portion of like mummies. Several had their seatures, hair, and eyebrows the compound volatilizes unchanged, and forms an annular red perfect, and these were photographed. The hair is very deposit upon the cooler part of the tube ; another portion loses slightly wavy, and softer than that of the ordinary Indian, iodine and yields a second sublimate, yellow in colour, of the almost silky in fact. They were small people, and reminded Mr. other conip und of phosphorus, boron and iodine, (PBI),, preLumholtz strikingly of the present Moqui village Indians. The pared by M. Moissan ; the remainder of the PBI, becomes Moquis, like the Zuñis, have a tradition that they came from converted in situ into the normal phosphide of boron, PB. The the south, The same district abounds in mounds, some of heating of the PBI, is best effected in a U-shaped tube immersed which are very large. Mr. Lumholtz thinks that an explorer in a bath of sused nitre. After the reduction is completed as might find in these mounds a fine field for investigation. far as possible, which is determined by the cessation of the With his own limited force of men he was not able to make evolution of vapour of hydriodic acid, the U-tube is removed as extensive excavations as he wished to make ; but still, a from the bath, and the residual phosphide extracted, powdered good deal of work was done. He unearthed a great many rapidly, and again placed in the tube, and the reduction continued polished stone implements, about 300 jars, most of them for a short time longer, in order to insure the removal of the last

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traces of iodine. The phosphide of boron thus obtained is a years. Since the observed transits of Mercury extend over more brown powder, very light in texture, and insoluble in every

than two centuries, M. Tisserand has discussed them with the solvent which has yet been tried. In contact with oxygen the

idea of determining whether the term 3":842 is really indicated by

them. He finds, hou ever, that the extreme transits are not so compound ignites at a temperature about 200°, and burns with a

well represented with the new term as without it, although the very brilliant flame, forming boric and phosphoric anhydrides. difference is not very great. This result, therefore, is unfavourWith chlorine gas it infames at the ordinary temperature, pro

able to the idea as to the variability of the sidereal day, or at ducing boron trichloride and phosphorus pentachloride. Vapour

least to a variation sufficient to reconcile the result of Airy's

This of sulphur converts it into sulphides of boron and phosphorus.

research with the calculations of Adams and Delaunay.

being so, it is concluded that the increase in the lengih of the When thrown into a little fused nitre instant incandescence and

day, produced by tidal action, has nearly the same value as the deflagration occur. Its behaviour with vitric acid is charac. diminution which results from the contraction of the earth caused teristic; it immediately becomes incandescent, and moves rapidly by secular cooling, and that, on account of the compensating to and fro over the surface of the acid, all the while burning action of the two effects, the length of the sidereal day remains with a most dazzling flame. It reduces concentrated sulphuric very nearly invariable. acid to sulphur dioxide. Fused potash decomposes it with

STATE OF SOLAR ACTIVITY.-Prof. Tacchini gives, in evolution of phosphoretted hydrogen and formation of potassium made at the Royal Observatory of the Roman College during

Comptes rendus for November 30, a résumé of solar observations borale. Sodium or potassium, in an atmosphere of hydrogen, July, August, and September of this year. The number of days react upon warming with great energy, the mass becoming white- of observation were 31 in July, 31 in August, and 19 in hot. Magnesium, heated with the phosphide to 500°, also reacts September, and the results obtained are as follows:with incandescence. Even silver and copper react violently

Relative frequency

Rela'ive magnitude upon heating with phosphide of boron. Vapour of water

of days
decomposes it at 400°, with production of boric acid and phos- 1891.
phoretted hydrogen. Heated to 300° in ammonia gas it takes

July
18:65

76-25

82'03 fire, and burns with formation of nitride of boron and deposition

August ...

8.84

0'06 of phosphorus.

September 17:52

114.45

6110 The second compound of boron and phosphorus, PzPz, was

A comparison of these numbers with those determined in the obtained by M. Moissan by heating the compound PB just preceding quarter shows that solar activity lias sensibly increased,

for the spotted surface has twice the area. It will be seen that described in a current of hydrogen to a temperature near 1000°. the minimum magnitude of faculæ occurred at the time of a Under these circumstances a portion of the phosphorus is maximum of spots. The following are the results obtained for eliminated, and condenses in drops in the colder part of the prominences :

Prominences. tube, leaving the P,B, in the form of a light brown powder,

Number of 1891.

days of which is distinguished from the normal phosphide BP by its

height. indifference to chlorine and nitric acid. It is much more stable than the normal phosphide, but is, like the latter compound,

July

30 August

30 decomposed with incandescence by fused nitre.

410 I'9

September... 23 9:26 414 The additions to the Zoological Society's Gardens during the The number of prominences recorded is greater than during the past week include a Formosan Fruit Bat (Pteropus formosus) preceding three months. The highest prominence (142") was

observed in August. from Formosa, presented by Mr. Thomas Perkins, F.Z.S. ; a Palagonian Cavy (Dolichotis palachonica) from Patagonia, pre

OBSERVATIONS OF A CEPHEI.-Mr. J. E. Gore made some

observations of the variable star u Cephei, the "garnet star" of sented by Mr. H. H. Sharland, F.Z.S. ; a Blotched Genet

Sir William Herschel, between January 1888 and December (Genetta tigrina) from South Africa, presented by Mr. Edmund 1890, which show that the variation of light is very irregular, R. Boyle ; a Grey Ichneumon (Herpestes griseus) from India, and that the star sometimes remains for several months with presented by Mr. G. F. Hawker ; a Little Grebe (Tachybaptes little or no perceptible change of magnitude (Proc. Royal Irish fluviatilis), British, presented by Mr. T. E. Gunn; a Tuatera Acad., January 26, 1891). Lizard (Sphenodon punctatus) from New Zealand, presented by

Astronomische Nachrichten, No. 3067, contains an account of Mr. W. King; a Brush-tailed Kangaroo (Petrogale penicillata)

the investigation, carried out by Herr Dr. Walter Wislicenus from New South Wales, purchased ; three Carpet Snakes

on the “Influence of Ring and Disk Blinds in Micrometic

Measurements,” in order to account for the following pheno(Morelia variegata) from New South Wales, received in

If one lifts a transit off its pillars and places it so that exchange.

2'2

it does not interfere with the line of sight of the collimators, and then brings the central wires of each collimator exactly in

coincidence, it is found that, by putting the meridional circle OUR ASTRONOMICAL COLUMN.

back again, and placing it in its vertical position with the

apertures in the central cube open, coincidence of the wires no THE SECULAR ACCELERATION OF THE MOON AND THE longer exists, but a slight displacement is noticed. It may be LENGTH OF THE SIDEREAL DAY.-Laplace showed that the remembered that this question was raised at Greenwich as early secular diminution of the eccentricity of the earth's orbit ought as the year 1868, while in the two following years, from to produce in the longitude of the moon a term proportional to observations made in that interval, a correction of o":48 and the square of the time, and which he determined as + 10",0":58 was found for the difference of reading. In 1874 this where t is expressed in centuries. Adams and Delaunay have discrepancy was accepted as real, and corrections for it were made, reduced this term to + 6":111". From a discussion of eclipses Airy but no real origin for it was assigned. Mr. Turner, in the year concluded that the coefficient of acceleration is as much as 12" 1886, also investigated this difference of reading, employing the or 13"; and accepting this, the question arises as to the cause, collimators of the transit circle at Greenwich, and ihe numerical other than that indicated by Laplace, which will account for the results obtained were given in vol. xlvi. p. 329, of the Monthly difference of 6"A. This forms the subject of a paper by M. Notices. By using a wooden model of ihe central cube of the Tisserand in Comfles rendus, No. 20, 1891. Prof. Darwin transit, he got essentially the same results as those given found that the tidal action between the earth and the moon was by the cube in the ordinary manner, but both were in sufficient to furnish an apparent acceleration equivalent to the discordance with the readings taken when nothing was interrequired complement. The accompanying decrease in the earth's posed. To account for the difference he says : “ The discrepancy rotational velocity produces an apparent acceleration of 3":842 in is due to a real difference between the lines of collimation of the case of Mercury, an amount which may make the longitude the central and eccentric portions of the object-glasses of the of the planet vary by as much as 15" in a couple of hundred ) collimators.”

menon.

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