plovers which have been trampled on by these uncouth marauders in their clumsy and ever eager attempts to 'annex' everything they can in the least possible time." The editor of :he Zoologist pertinently asks why the Wild Birds Protection Act is not put in force.

AT the meeting of the Linnean Society of New South Wales on November 25, Mr. Fred. Turner exhibited specimens of lelopea oreades, F. v. M. (narrow-leaved form), the Victorian Waratah, [collected at the Fitzroy Falls, N.S. W., the most northern habitat yet recorded for the plant; said to be very rare. Also three fungus-smitten grasses from the interior: Eriochloa bunctata, Hamilt., Panicum Mitchelli, Benth. (two valuable pasture grasses-in the case of the second of these the first occasion on which he had seen fungoid growth on it), and Aristida ramosa, R. Br., one of the "three awned spear grasses," a noxious plant. To the presence in fodder of parasitic fungi such as these, the fact that many sheep died so mysteriously at times was, Mr. Turner thought, sometimes possibly attributable.

MESSRS. WHITTAKER AND Co. have made arrangements with the editor of El Telegrafista Español for the translation into Spanish of Mr. Preece's work upon "The Telephone." The book has already been translated into French and German. The same firm will publish shortly, in a cheap form, Mr. A. R. Bennett's papers on the telephoning of great cities and the electrical parcel exchange system.

WE are glad to welcome the first number of The Annals of Scottish Natural History, a quarterly magazine, with which is incorporated The Scottish Naturalist. It is edited by J. A. Harvie Brown, J. W. H. Trail, and W. E. Clarke, and published by David Douglas, Edinburgh. The periodical ought to play an important part in stimulating the study of natural history in Scotland.

AN important botanical work has been planned by T. Durand, aide-naturaliste at the Botanic Gardens of Brussels, and H. Schinz, privatdocent at the University of Zürich. It is entitled "Conspectus Flora Africa," and will be published (by subscription) in six volumes.

THE Botanical Society of Edinburgh prints, in the latest instalment of its Transactions and Proceedings, a capital" preliminary notice" of the Pilcomayo Expedition, by Mr. J. Graham Kerr, naturalist to the Expedition. Mr. Kerr gives a short sketch of the Expedition itself, and then presents a summary of the more striking botanical features of the region traversed by it.

MESSRS. J. AND A. CHURCHILL have published the "Yearbook of Pharmacy," comprising abstracts of papers relating to pharmacy, materia medica, and chemistry, contributed to British and foreign journals from July 1, 1890, to June 30, 1891. The volume also contains the transactions of the British Pharmaceutical Conference at the twenty-eighth annual meeting, held at Cardiff, August 1891.

MESSRS. DULAU AND CO. have issued a catalogue of geological works which they offer for sale. The works relate to crystallography, mineralogy, mining, petrography, boulders, caves, vulcanology, water, &c.

SEVERAL new compounds of carbonyl platinum chloride and bromide with ammonia derivatives are described by Dr. Foerster in the current number of the Berichte. An account of the interesting carbonyl platinum compounds was given in NATURE,

vol. xliv. p. 530, cn the occasion of the publication by Drs. Foerster and Mylius of the results of their investigation concerning them. They were first obtained in 1868 by Schutzenberger by heating spongy platinum first in a stream of chlorine and afterwards in a current of carbon monoxide. The most stable and best investigated of these substances is the compound COPtCl. It is a crystalline substance possessing a somewhat basic character. The crystals readily dissolve in concentrated hydrochloric acid, forming the hydrochloride COPtCl HCI. Nevertheless, the substance appears capable of combining with ammonia or its derivatives, for Schutzenberger obtained a compound, to which he assigned the formula COPtCl. 2NH3, by passing ammonia gas through a solution of carbonyl platinum chloride in carbon tetrachloride. As this ammonia compound does not readily lend itself to accurate analysis, Dr. Foerster determined to prepare a compound with a base such as aniline or pyridine, which would probably form crystals more capable of thorough investigation. For this purpose he chose the base pyridine, CH,N. He finds that carbonyl platinum chloride does not combine with two, but with one molecule of the base, to form the compound COPtCl.C,H,N. This result is all the more satisfactory, inasmuch as Zeise has shown that the compound ethylene platinum chloride, CH,PtCl, forms an analogous compound with one molecule of ammonia of the composition CH,PtCl NH3. The new compound with pyridine, COPtC.C5H5N, is a crystalline substance possessing basic properties, combining with hydrochloric acid to form the hydrochloride, COPtCl. CH5N. HCI. Another new compound is obtained from the hydrochloric acid solution by the addition of more pyridine dissolved in alcohol, crystallizing out upon allowing the solution to stand a short time. When recrystallized from alcohol, this second compound is obtained in fine greenish-yellow crystals. Its empirical composition is COPICI.C,H,N, but its molecular composition is probably represented by the double formula

COPICI.C,H,N

COPICI.C,H,N

Water instantly decomposes it. In a similar manner two analogous compounds containing bromine have been obtained. The first of these, COPtBr. C3H,N, crystallizes in yellow tabular or acicular prisms, melting at the temperature, very low for a platinum compound, of 78°. The second compound, (COPtBr)2(C5H,N), is distinguished by its difficult solubility, only chloroform dissolving it in sufficient quantity for the purpose of recrystallization.

IN addition to the above compounds with pyridine, an interesting compound with phenylhydrazine has been obtained, COPtCl C¿H5NH ̧, in fine crystals. The hydrochloride of this compound, COPtC. CH3NH3. HCl, has also been prepared; it forms remarkably beautiful orangecoloured crystals. Indeed, it appears highly probable that hydrazine itself, NH, would be found to combine with these carbonyl compounds of platinum in a manner similar to

ammonia and its derivatives.

THE additions to the Zoological Society's Gardens during the past week include a Diana Monkey (Cercopithecus diana ?) from West Africa, presented by Mrs. R. Godfrey; a Rougheyed Cayman (Alligator sclerops) from South America, presented by Mr. Charles Taylor; four Mississippi Alligators (Alligator mississippiensis) from South Carolina, presented by Mr. W. S. Copleston; four Gouldian Grass Finches (Poëphila gouldiæ}, two Crimson Finches (Estrelda phaeton) from Australia, purchased; four Beautiful Grass Finches (Pophila mirabilis) from Australia, purchased.

12-inch. The results obtained by the former indicated a small change, so small indeed that Mr. Barnard with his instrument could not detect any variation, or at any rate any difference of reading that would not be masked in the errors of observation. Mr. Burnham's measures are shown in the form of a curve, a vertical line corresponding to the time of nearest approach of the nucleus to Asterope, while a horizontal one indicates the mean Ad. The dots representing the observations gradually increase their declination, and then more quickly decrease, rising again only when the comet has transited the star. The results are most interesting, and the following is a short extract from the table. The time of nearest approach of the star and the nucleus occurred at 2h. 8.7m. sidereal time.

Difference of Declination between 21 Asterope and 22 Asterope.

Right Ascension.

h. m. S.

4 15 15

13 39 5

3'24

1.26

94.86

2'5

3'5

27

56 33

4'5

5 1 30

5'5

6'5

7'5

8.5

vivivivivivivi

94.60

Sidereal

I

6 O

30 The comet is now a comparatively faint object, but can be seen with instruments of moderate aperture. It is in Eridanus, and moving slowly towards Orion. It has the same declination as Rigel on February 9, and passes about 4° north of this star on March 7.

THE DIFFRACTION EFFECTS PRODUCED BY PLACING SCREENS IN FRONT OF OBJECT GLASSES formed the subject of a communication by Prof. Pritchard to the Paris Academy on December 28. The paper deals with the effects produced by meshes of metallic wires on the photographic and visual images of stars in the focus of refractors (photographic and ordinary) and reflectors. Numerous screens have been used in the investigation, but only the results obtained with three, designated by A, B, and C, are described. A was an iron wire screen having very nearly square meshes about o'9 mm. apart, B a bronze one with meshes having an area of about 0'225 square mm., and C one having circular holes about 2'3 mm. diameter in it. Photometric observations of the intensities of the visual images of a bright star with and without A gave the relation 13636 which, expressed in units of stellar magnitude of the ordinary scale, corresponds to an absorption by the screen of 140 magnitude. The same screen placed in front of a photographic telescope reduced stars of the ninth to the eleventh magnitude. There was thus a variation of of a magnitude in the effect produced by the same screen on the visual and photo. graphic images of the same star. B intercepted light equivalent to 24 magnitude in the case of the observing telescope, and 2.8 magnitude in the case of the photographic one. C gave the values 1'44 and 183 magnitudes respectively. In all cases, therefore, the absorption of light was greater for the photographic than for the visual image. This is most probably due to the different treatment of the lenses by the optician in correcting them for photographic or visual work. Using the

same

screens in connection with reflectors, the intensities of the visual and photographic images were found to be the same, and the quotient of the intensity without a screen into the intensity with a screen was very nearly equal to the square of the portion of the screen traversed by the light.

REFRACTIVE POWER OF COMETARY MATTER.-Mr. Barnard communicates a paper to the Astronomische Nachrichten, No. 3072, on observations made of the difference of declination of 21 Asterope and 22 Asterope at the passage of Wolf's couet, 1891 September 3, through the Pleiades. As the opportunity afforded a good test to determine the refractive power of cometary matter, he, together with Mr. Burnham, instituted a series of measures of the declination of these stars before, during, and after, the transit of the comet over Asterope. Mr. Burnham's observations were made with the filar micrometer of the 36-inch equatorial, while Mr. Barnard used that of the

HIMMEL UND ERDE.-The December number of this monthly " " contains an interesting article by Dr. W. Zenker on "The Heating of the Earth's Surface by the Sun." That on "The Great Ice Age," by Prof. Dr. Albrecht Penck, begun in the November number, is here completed.

"WASHINGTON OBSERVATIONS, 1886."-This volume, just issued, contains the results of all the observations made during the year 1886 at the United States Naval Observatory, under the superintendence of Commander A. D. Brown, U.S.N. Under the heading of "The Transit Circle" and "The Meridian Transit Instrument," are given descriptions of the instruments, catalogues of miscellaneous stars observed, constants used in reductions, adopted corrections, clock rates and corrections, positions and semi-diameters of sun, moon, and planets, and many other details. Under "Observations and Results' are tabulated all the results obtained by the use of the transit circle, meridian circle, the equatorials of 26 and 9.6 inch aperture, &c. The magnetic observations made during the years 1888 and 1889 at the same Observatory by Ensign J. A. Hoogewerff, U.S.N., under the superintendence of Captain F. V. McNair, U.S. N., are also given, including both tabular statements and fourteen large plates.

MOLECULAR WEIGHT OF GADOLINIA. IN Bihang till K. Svenska Vet.-Akad. Handlingar, Band 17, Afd. ii., No. 1, Prof. A. E. Nordenskiöld returns to a subject which will always have a peculiarly fascinating interest for chemists. In spite of the vast amount of time and labour which has been expended upon the investigation of the rare earths contained in such minerals as gadolinite and samarskite, the mystery involved in the peculiar nature and reciprocal relations of these bodies is still far from having been solved.

It was in 1794 that Gadolin first examined the mineral gadolinite. Since that time the exceedingly complex nature of the new earth which he discovered has been continually demonstrated. Every fresh investigation seemed to result in the announcement of the discovery of a new element. The task of separating these different earths, which are so closely allied in their chemical properties, was exceedingly difficult and tedious. Mosander was one of the first to make use of the process of fractional precipitation, which, combined with spectroscopic methods, has in the hands of such scientific men as Delafontaine, Marignac, Lecoq de Boisbaudran, and Crookes, led to such interesting results. The investigations of Crookes on these rare earths resulted in the famous lecture on the "Genesis of the Elements," delivered before the Royal Institution in 1887.

The mention of this remarkable lecture brings us to the subject of the present paper, for one of the arguments employed by Crookes was that we had proof of the existence in nature of a mixture of isomorphous bodies, always associated together, and presenting a molecular weight so constant that they almost constitute a single body. That statement was made by giving

importance (an exaggerated importance according to Marignac's criticism) to an interesting observation made by Prof. Nordenskiöld, who had announced (Comptes rendus, ciii. (1886), 795) the fact that the crude mixture of yttria earths, as precipitated from different minerals, although really a compound body, has nevertheless always a constant molecular weight, whatever may be the mineral from which it is extracted. To this mixture of earths, which thus behaves like an element, Prof. Nordenskiöld gave the name gadolinia, or oxide of gadolinium. In a subsequent paper (Ofversigt af Vetenskaps-Akademiens Förhandlingar, 1887, No. 7) in answer to the criticisms of Marignac and Rammelsberg, he showed that although the molecular weights for the individual earths which make up gadolinia vary between 136 and 394, yet the molecular weight for the mixture as a whole, obtained from a number of different minerals from various localities, only varied from 258 to 271.

The work of which an account is given in the paper now before us was undertaken in order to discover whether the above slight differences were only dependent on variations in the experimental methods. The author has not attempted to make any separation of the individual earths, but has confined himself to further determinations of the molecular weight of the group as a whole. The result of fifty-four determinations made upon such minerals as gadolinite, orthite, samarskite, monazite, &c., from various localities was to show that gadolinia from widely different sources has a molecular weight ranging from 2479 to 2758. The gadolinia used in these determinations was obtained by first separating the cerium metals by precipitation with potassium sulphate, precipitating the filtrate with ammonia, dissolving this precipitate, and reprecipitating with oxalic acid. Care was taken to avoid any fractionation which might occur, but any fear on this account was discounted by the unexpected discovery made during the course of the work that any gadolinia fractioned out (e.g. thrown down with the cerium oxides in the K,SO, precipitate) had a molecular weight differing only very slightly from that of the rest of the earth.

The criticism which the author next applies to eighty-one molecular weight determinations made by Blomstrand, Engström, Rammelsberg, and others, leads to the rejection of forty, either owing to the small amount or to the impurity of the material used. The numbers in the case of the forty-one determinations retained fall within the limits obtained by the author.

Now, the molecular weights of the twelve earths which are at present stated to enter into the composition of gadolinia range from that of scandia, 136, and yttria, 227, to that of ytterbia, 394; so that the fact that, in spite of this wide divergence in the molecular weights of the constituents, the molecular weight of gadolinia itself only varies by at most 5'4 per cent. from the mean value, 262, is sufficiently startling. Thus no gadolinia has yet been found containing exclusively one only of these individual earths. The author shows, by a review of other minerals containing isomorphous groups of elements, how distinct in this respect is the behaviour of this group of yttria earths.

We have seen what use Crookes has made of these curious facts. We will conclude, therefore, by giving Marignac's conclusions on the same subject, as contained in his criticism of the author's previous paper. He is of opinion that all that can be affirmed is that yttria is always met with in nature mixed with a variable number of analogous and isomorphous earths of much higher molecular weight, and that it is always the dominating element in this mixture. G. T. P.

SOCIETIES AND ACADEMIES.
LONDON.

Physical Society, December 18, 1891.-Prof. W. E. Ayrton, F.R.S., President, in the chair.-The President announced that it had been found necessary to alter the dates of the meetings to be held after Christmas from those already published to the following: January 22, February 12 and 26, March 11 and 25, April 8, May 13 and 27, June 10 and 24.-A note on interference with alternating currents was communicated by Mr. M. H. Kilgour. Whilst studying Dr. Fleming's paper on some effects of alternate current flow in circuits having capacity and self-induction, the author constructed some additional curves. He was thereby led to investigate whether the serious rises of pressure produced by adding capacity would occur over considerable ranges of capacity, or whether they would only take place when the capacity was nearly equal to a particular value.

=

A =

R2 + L2 R

(2)

Taking R 10, and p 2π. 1000, curves plotted from equations (1) and (2) between C and L, and between A and L had been drawn. The CL curve rises to a very sharp peak at L = 0.0015, and falls rapidly. That between A and L starts horizontal and bends upwards, and approximates to an inclined straight line for values of L greater than o'002; when L = o'1, A = = 63. Considering the question of the range of capacity with which a given rise of pressure can occur, it was pointed out that when the values of L, R, and p are such as to make a large rise possible, a rise exceeding a moderate value can only be obtained for values of C differing little from that given by equation (1). On the other hand, when the circuit is such that the maximum rise possible is not large, then a rise exceeding a given moderate value can be obtained over a much wider range of capacity. Hence the author concludes that the larger the possible rise the smaller is the probability of a serious rise occurring. The effect of shunting the condenser by a circuit of resistance and inductance is next dealt with in the paper, and the values of C which make λ a maximum determined, as well as the maximum value L can have. Subsequently the feeding a transformer through a concentric cable may be simpliauthor examines whether the practical case of an alternator fied without introducing serious error by assuming the capacity concentrated at either end of the cable, and concludes that in ordinary cases little error will be thus made. In an experiment made with a 100 kilowatt alternator, mile of concentric cable, and an 18 kilowatt transformer, a rise of per cent. was found to occur at the terminals of the alternator when the cable was connected. Putting on the transformer unloaded or loaded with but a dozen 16 candle-power lamps produced little change in the rise of pressure, this in all cases being between o*2 and 0.3 per cent. Dr. Sumpner asked whether the conclusions as to the range of capacity with which a given rise of pressure was possible, were true for small rises such as occur in practice. Cases where the maximum possible rise was of the order 63 were not likely to occur at ordinary frequencies. The highest rise he had ever known was II. He thought the time-constant of the inductive coil chosen-viz. 1 of a second-was very large. In circuits containing iron it was practically impossible to get such large time-constants, for the power spent in the iron increased the effective resistance. Referring to the narrow range of capacity within which large rises were possible, he pointed out that such cases were found in Hertz's resonators, where the rises were immense, but to obtain them the adjustments had to be very accurately made. Dr. S. P. Thompson said he regretted that Prof. Fleming was not present, for he had recently investigated Hertz's experiments, and had obtained curves very similar to those got for the Deptford mains. The curve between A and L was very interesting. It was, in fact, a curve between the secant of the angle of lag and L, as could be seen from formula (2). In practice one would be working on the lower portion, and hence the rises would be small. Mr. Kilgour explained that in the paper his first object was to show that the product of the ange of capacity between which a rise greater than a given value would occur and the maximum possible rise was approximately constant for different circuits. Secondly, he wished to prove that the capacity of concentric cables could be assumed to be localized at either end without introducing much error in the rises of pressure calculated therefrom. Dr. Thompson, speaking of nomenclature, regretted that the word inductance should be used sometimes for L and at other times for Lp, and thought its meaning should be restricted to the latter. Prof. Perry said a name was needed for coefficient of self-induction. Resistance was practically independent of frequency, and "inductance" should have no reference to frequency. Dr. Sumpner thought it important to have a name for Lp, for that quantity comes into calculations most frequently. He would have preferred that

attraction and its measurement by Cavendish and his successors, dealing specially with the work of Boys, whose methods he explained and whose apparatus he exhibited to the Society.

AMSTERDAM.

the lens containing a liquid is placed between a collimator and an observing telescope, furnishes the datum from which the index of refraction of the liquid can be calculated. The determinations that have been made indicate that the method is susceptible of high accuracy.-Researches on the application of measurements of rotatory power to the determination of combinations formed by sorbite in aqueous solution with acid sodium and ammonium molybdates, by M. D. Gernez.-Metallic borates, by M. H. Le Chatelier. The author has prepared, purified, and analyzed borates of magnesium, calcium, and zinc. He concludes that many of the complex borates previously described are in reality mixtures of comparatively simple borates with boric anhydride, and that the only types of borates of which the composition is sufficiently established are: BO3, 3MO; B2O3, 2MO; BO, 15MO; and BO3, MO. -On isomeric chromic sulphates, by M. A. Recoura.On a silicon chlorosulphide, by M. A. Besson. compound SiCl,S2 has been obtained as a white solid, crystallizing in long needles melting at 74°, readily decomposing in the air, and acted on with violence by water.— A new crystallized copper phosphide, by M. Granger.-The solution of antimony chloride in saturated solutions of sodium chloride, by M. H. Causse.-On a double cyanide of copper and ammonium, by M. E. Fleurent.-Study of the thermal properties of bibasic organic acids: influence of the alcoholic function, by M. G. Massol.-Disodium glycol, by M. de Forcrand.-Action of dilute nitric acid on nononaphthene, by M. Konovaloff.-The formation of acetylene from bromoform, by M. P. Cazeneuve.-Action of phosphorus pentachloride on methylnaphthyl ketones: a and 8 naphthylacetylenes, by M. J. A. Leroy.-Observations on the subject of a note of MM. Arm. Gautier and R. Drouin, by MM. Th. Schloesing, fils, and Em. Laurent.-On the formation of cordierite in the sedimentary rocks fused by the coal fires at Commentry (Allier), by M. A. Lacroix. An examination of some rock specimens from Commentry, where the underground combustion of coal has been going on for some time, shows that the most abundant mineral constituting the lavas formed (especially the ropy varieties) is cordierite. This mineral occurs in small crystals, which have not, however, been isolated and analyzed. It is accompanied by octahedric spinellids in connection with anorthite, and small, almost rectangular, microlites. The augite often exhibits the chrondritic structure of meteorites. The variation in the relative abundance of cordierite, anorthite, and augite, their very unequal dimensions in different specimens, and the relative abundance or rarity of the glass, give rise to numerous interesting petrographical varieties. Mallard's rhabdite has been easily recognized. The facts show that cordierite is easily formed by the action of heat on sedimentary rocks; indeed, it appears from the observations to be an habitual product of Carboniferous rocks modified by heat.Functions of the pectiniform organ of scorpions, by MM. Charles Brongniart and Gaubert.-On the régime of the oceanic sardine in 1890, by M. Georges Pouchet.-On the presence of Heterodera Schachtii in cultures of carnations at Nice, by M. Joannes Chatin.-On a phtiriasis of fibrous copper, caused, in an infant of five months, by Phtirius inguinalis, by M. Trouessart.-Observations on the cellulosic membrane, by M. L. Mangin.-On the penetration of the violet filaments of the Rhizoctone fungus in the roots of beetroot and lucern-grass, by M. Ed. Prillieux.On the assimilation of parasitic plants by chlorophyll, by M. Gaston Bonnier.-Earthquake of October 28, 1891, in Central Japan, by M. Wada.

BERLIN.

Physiological Society, December 11, 1891.-Prof. du Bois Reymond, President, in the chair.-Prof. Fritsch gave an account, illustrated by specimens and preparations, of the general result of his investigations on feebly electrical fishes, as far as these dealt with the structural arrangement of the electric organ, the nerves to the same, and the nerve centres.-Dr. C. Benda spoke about his recent researches on spermatogenesis, entering fully into the part played by the archoplasm in the development of spermatozoa.

Physical Society, December 18, 1891.-Prof. Kundt, President, in the chair.-Prof. Schwalbe recalled to the Society the loss it had sustained in the death of Dr. Ewald, one of its earliest and formerly most active members.-Dr. Budde gave a résumé of the work which has been done during the last ten years on supersaturated solutions, and an account of the present state of the question.-Dr. Paschen spoke on gravitational

branches have two points of sharp intersection. In the first coexist the double salt with FeCl3.6H2O, in the second the double salt with mixed crystals containing the highest possible percentage of FeCl3. These results confirm the rule that with systems of three bodies the composition of a solution is variable when only one solid phase lies at the bottom, but determined when there are two solid phases. The occurrence of mixed crystals besides double salts modifies the behaviour of the solution when one or other of the composing salts is added continuously.-Mr. J. A. C. Oudemans spoke on levels. He had had to try two levels of an altazimuth of the Sumatra triangulation, having each an air chamber at one of their ends; using a bubble not longer than one-third of the scale, he found the value of a division in the first and last third two or three times larger than in the middle, so that he inclined to reject the levels. But trying the same levels with long bubbles-for instance, of twothirds of the scale-they proved much better, the inclination given by the level-trier being nearly proportional to the indication of the level, and the remainder of the irregularity being easily taken into account by a table. The necessity of making up, by experiment, a table of the inclination in a function of the level-reading, being once admitted, the judgment about a level ought to depend, not so much on the uniformity of the curvature, as on the constancy (the bubble remaining of the same length) of the reading, the inclination being the same; which property may easily be tested by the level-trier.