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On the night of July 6th a great outburst of the comet was observed at Cincinnati, Ohio, by Mr. Wilson and Professor Stone. The former first noticed a peculiar glare on the side toward the tail. The appearance was that of a large jet of matter, of a red or exceedingly bright color, shooting out from the comet. The phenomenon was so striking as to suggest the incipient separation of the comet into parts.

Encke's comet was detected on August 20th, by Dr. Hartwig and Professor Winnecke, with the six-inch comet-seeker of the Strasburg Observatory. This was its twenty-ninth return since its first appearance in 1786. The positions of this body are observed and discussed with a lively interest at each successive return, as Encke's celebrated theory of a resisting medium must stand or fall by the evidence de

rived from its motion.

The fifth comet of 1881 was discovered on the morning of September 19th, by Professor E. E. Barnard, of Nashville, Tennessee. Its elements are somewhat like those of the comet of 1698, as is shown by the following comparison:

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its descending node, so that the comet is occasionally liable to considerable disturbance.

On the evening of November 16th, Dr. Swift, of the Warner Observatory, Rochester, New York, discovered a faint comet in Cassiopeiathe second detected by him since May 1st.

The Meteors of August and November.-The number of meteors seen about the 9th and 10th of August, 1881, was less than usual-a fact partly due to the brightness of the moonlight. The shower of November 14th-15th also failed, no Leonids having been seen in certain places where looked for. According to the "National Republican" of November 15th, a meteor of great brilliance was seen at Washington, D. C., about five o'clock on the morning of the 14th. It was described as a broad band of meteoric light starting from a point a little west of north, and about 60° above the horizon. This meteor, which was visible at least ten seconds, was probably a member of the Leonid stream.

Motions of the Fixed Stars.-The monthly notices of the Royal Astronomical Society for January, 1881, contain a fourth paper by Sir George B. Airy on spectroscopic results for the motions of stars in the line of sight, observed at the Royal Observatory at Greenwich. According to this table, the following are the rates

of motion of certain well-known stars: Of the two pointers in the Dipper, Dubhe, that the rate of twenty-seven miles per second, nearer the pole-star, is approaching the sun at locity. In the same asterism, Phekda, Migrez, while Merak is receding with nearly equal veAlioth, and Mizar, are all receding at the average rate of sixteen miles per second, while Benetnash is approaching the solar system with a velocity of eight miles a second. In the Square of Pegasus, Alpheratz, Algenib, and Markab, are approaching at the rates of thirtythree, forty-six, and thirty-four miles per second, respectively, while Scheat is approaching at the rate of nineteen. The distance of Castor is increasing twenty-five miles per second, and that of Pollux decreasing at the rate of twenty-six. The distances of Aldebaran and Regulus are both increasing; the former twenty miles per second, the latter twenty-six.

The Distribution of the Variable Stars.—In "The Observatory" for September, 1881, Mr. T. E. Espin gives the following results of a careful study of the distribution of the variable stars: "1. The variable stars show a decidedly well-marked zone inclined 15° or 20° to the equator.

"2. This zone crosses the preceding side of the galactic circle north of the equator, and the following south of it.

"3. In crossing the preceding side of the galactic circle, the zone is not many degrees broad, and is very clearly marked; where it crosses the following side it is broken up into two streams.

"4. The division into two streams occurs where the galaxy is also divided into two

streams.

"5. In this part the variable stars are intimately connected with the galaxy, often falling in the gaps, and constantly on the edges of the gaps, but rarely in the center of the star-sprays from the galaxy. Where the zone crosses the preceding part of the galaxy, it is marked sharply and clearly, and seems unconnected with the galaxy.

"6. It is a remarkable thing that all the temporary stars with one or two exceptions have appeared in the region where the galaxy and the variable star zone are both broken into two streams.

"7. The exceptions to the zone are chiefly found in the bright and short period variables. "8. The addition to the chart of the stars more strongly suspected variable, and that on competent authority, strengthens the zone very much indeed, and but very slightly the number of exceptions."

The fact that nearly all variable stars of short period are found in a particular zone has also been remarked by Professor E. C. Pickering, of the Harvard College Observatory. Professor Pickering describes this zone as extending 16° on each side of a great circle whose pole is in right ascension 195° and north declination 20°. The average distance of thirty-one well-known variables of short period from this great circle is 5° 30', while a random distribution would give an average distance of 30°.

Gold Medal of the Royal Astronomical Society. At the annual meeting of the Royal Astronomical Society of London, in February, 1881, the gold medal of the society was awarded to Professor Axel Möller, for his researches on Faye's comet.

ATLANTA EXPOSITION. (See EXPOSITION, ATLANTA.)

ATOMIC THEORY. There have been many attempts to establish a law of numerical relations between the atomic weights of the elements. The discovery of definite ratios between the atomic weights and other quantitative attributes, the division of the elements into specific groups distinguished by well-marked properties, and the tendency to doubt their primary character and to regard them as derivative combinations of simpler bodies, give a fresh impetus to speculation in this direction.

Mendelejeff's periodic law, confirmed as it has been by the discovery of gallium and other predicted elements, and by the agreement of many established facts with his scheme of periodic functions, which more exact quantitative determinations have rendered more complete, has been elevated into the rank of an accepted theory.

The Russian chemist has correlated the elements according to a synthetic law which is the most comprehensive yet established in chemistry, co-ordinating all the physical properties and the chemical affinities of the whole list of simple bodies. Arranging the elements in the order of their atomic weights, their densities, and consequently their atomic volumes,

which depend upon the density, and their combining numbers in compounds with other elements, each follow a certain progressive order in successive groups of the elements. Similar properties recur with complete regularity, and follow the same order of progression in the successive series. The properties are modified as the atomic weights increase; but the modifications affect entire groups, and do not interrupt the gradual progression within the periods. The elements of the different periods in which the same or similar properties are repeated constitute the natural families already established by other chemists upon the ground of their identical combining numbers. The atomic weights of contiguous elements usually differ by only a few units. In cases where there is a considerable hiatus there is also found a gap in one or more of the natural orders, which should be represented here by members of intermediate atomic weights between those of the preceding and the following periods. Some of the gaps in Mendelejeff's scheme have already been filled by subsequently discovered elements. Gallium corresponds in atomic weight and in properties to one of the predicted elements, as do also the descriptions of scandium and ytterbium. Mendelejeff's periodic law is expressed in general terms in the following predicate: All the properties of elements, and consequently of the compounds which they form, are functions of their atomic weights, to which they stand in periodic relations. In the following table all the known elements are arranged in the order of their atomic weights. The horizontal series gives the successive cycles in which the period of progressive development is completed; and the vertical series, the natural or homologous orders of elements in which the same properties reappear.

In the following table, it will be seen, tellurium is the only substance which is out of place. Possibly a redetermination of its atomic weight will give it in this respect the position between antimony and iodine which its intermediate properties indicate. Iron, manganese, and chromium, which differ very slightly in atomic weight, do not exhibit the close resemblance in behavior and properties which the theory requires; and cobalt and nickel, which have almost identical atomic weights and densities, possess, in some respects, quite dissimilar properties. Other differences as remarkable are shown by potassium and calcium, and other proximate elements. Copper, which has many analogies with mercury, here falls in a different group. The gradations of properties are certainly not uniform and proportionate to the atomic weights in the different series, being excessive, for example, between carbon, nitrogen, oxygen, and fluorine.

Besides the density, the malleability, ductility, fusibility, volatility, and conductivity to heat and electricity of elements seem, in the same manner, to be subject to periodic variations following the increasing order of their

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atomic weights. Lothar Meyer has constructed a graphic representation exhibiting the relation of the physical properties of the elements to their atomic weights and volumes. The elements are arranged at distances from the origin along the axis of abscissæ proportional to their atomic weights. The ordinates of the curve indicate their atomic volumes, and the curve the variations of these in their successive order. From the portions of this curve which have been determined, it appears that it represents also variations in the above-mentioned physical properties. It is seen that the position of the elements on the ascending or descending portions of the curve determines their properties, which may thus be very different for bodies possessing nearly the same atomic weight, and yet harmonize in a remarkable manner with the other terms of the theory. The light metals which occupy the summits and contiguous descending parts of the curve are ductile; and the heavy metals at the bottom and lower part of the ascending curve are partially ductile. In the fourth group the ductility is seen to increase and diminish twice in one period of the variations of density. Fusibility and conductivity, with increasing atomic weights, exhibit the same principle of variability. Crystalline form and expansibility by

heat are found also to depend upon atomic weight, according to the same law of periodicity. Fizeau's experiments have proved that the co-efficient of expansion rises and sinks regularly as the atomic weight increases. Dulong's law of relativity between atomic weights and specific heats, probably for lack of exact measurements, can only be determined in cases where atomic weights and atomic volume are both low. Dulong's law is not periodic, the specific heat being uniformly inversely proportional to the atomic weight. Lecoq de Boisbaudran has proved that, in the homologous series of elements, the wave-lengths of the luminous rays which they emit are proportional to their atomic weights. The electro-chemical character of the elements follows the law of periodic variations, the passage from the electro-positive to the electro-negative character taking place in certain groups twice in the same period of density variation. The electro-chemical condition governs the power of combination, to a certain extent; the stable protoxides, for example, being formed with electro-positive metals, and powerful acids rich in oxygen with electro-negative elements. Electro-negative hydrogen, on the contrary, forms its most stable simple compounds with electro-positive elements.

In each of the periodical series the capacity of combining with oxygen seems to increase up to a certain point, and then to decrease. The series headed by silver may be taken as a type of the oxygen compounds formed by the elements in the other periods, the formulæ being here doubled for the sake of uniformity:

Ag2O; Cd202; In,O,; Sn2O.; Sb2O.; Te208; 1207; OsO1; IrO2; PtO2.

The first five members of every period but one follow these types exactly. The variations of affinities for chlorine and hydrogen within the groups are made evident by the following formulæ, combinations with hydrogen being confined to the last four terms of the groups: Li Cl; G Cl; B Cla; C Cl. Na Cl; Mg Cl2; Al Cl; Si Cl. CH.; NH3; Ó H2; F H. Si H.; P H.; S H2; Cl H. Dumas, to whom the merit of grouping the elements into natural families belongs, called attention again to Prout's neglected hypothesis in 1879. The French chemist discovered simple numerical relations between the metalloids and some of the families of metals belonging to each group. In the sulphur group, for instance, at the head of which oxygen is now placed, there is a progression representing additions to the atomic weight of the initial body of multiples of a common difference. Starting with oxygen, whose atomic weight is 8, the next member, sulphur, has the atomic weight 16, formed by the addition of the increment 8; selenium has 40, corresponding to the addition of four times this difference to the weight of oxygen; and tellurium 64, an increment of seven times the difference. In the lithium and magnesium groups there are like simple progressions. In the families of fluorine and nitrogen he has established arithmetical relations of a more complex order.

A recalculation of atomic weights, based on the determinations of Stas and other data, has impelled Professor F. W. Clarke, following Mallet and Dumas, to revive the abandoned hypothesis of Prout, according to which the atomic weights of all the elements are multiples of the atomic weight of hydrogen. Among the 65 determined elements when their atomic weights are referred to that of oxygen, in order to avoid the multiplication of the variation of oxygen from Prout's hypothetical law, it is found that 39, as calculated by Clarke, do not vary more than 0.1 from exact multiples of the atomic weight of hydrogen; and of the remaining 26, 3 are almost exact half-multiples; 5 are rare or vaguely determined elements; 2 are subject to the constant error from the occlusion of oxygen, detected by Dumas in the 'case of silver, potassium, and iodine; 1, thallium, is brought within the limit by a correction of Crookes's calculation; 2, glucinum and ytterbium, can also be brought by a recalculation within the limit; and 1, antimony, is almost an exact multiple of hydrogen, according to a recent analysis of the bromide; for 4,

mercury, chromium, vanadium, and gold, new determinations are wanted; and the remaining 8 are still subject to slight revision. Professor Clarke concludes, then, that as three fourths of the well-determined atomic weights agree with Prout's hypothesis, the seeming exceptions may be due to undetected constant errors, such as have been brought recently to light in some of the most familiar bodies in the entire list of elements.

Maximilien Gerber has sought to determine common factors in the atomic weights of the component members of each of the elemental groups, and has determined empirically certain common divisors in the several groups whose multiples vary but slightly from the experimentally-determined atomic weights. In the group of mono-atomic elements the common factor is 0.769. The alkaline metals, lithium, sodium, potassium, rubidium, and cæsium, which combine with oxygen after the type R2O, and with chlorine according to the formula R Cl, have, excepting the last named, the additional common factor 3. The non-metallic halogens, fluorine, chlorine, bromine, and iodine, are another division of this class, and are likewise multiples of 0.769.

The atomic weight of hydrogen is related to this number in the ratio 10:13, and that of silver is an exact multiple. The di- and tetraatomic elements have the common divisor 1·995. Oxygen has an atomic weight equal to eight times this number, and the weights of sulphur, selenium, and tellurium are multiples of that of oxygen.

The alkaline-earthy metals, magnesium, calcium, and strontium, which have the combining formula RO, have the quadruple of the original factor for a divisor; but barium, which belongs to the same group, does not. Carbon, silicon, titanium, zirconium, and tin, have only the one common factor. Mercury, molybdenum, tungsten, and uranium, are also multiples of this number. The tri- and penta-valent elements, the group of nitrogen, boron, etc., which form a stable oxide of the type R,O,, and chlorides of the types RC, or RCs, have most of them the common factor 1.559 in their atomic weights. The fourth and most numerous class, combining into the oxides RO and R.Os, have atomic weights which are approximate multiples of 1.245. Gerber's provisional determination of common divisors is found to agree with two recent corrections of atomic weights: that of tellurium, which, as redetermined by Will, is 127-8, a number which accords better with Mendelejeff's scheme; and that of glucinum, which, according to the findings of Nilson and Petterson, should not be classed among the diatomic alkaline-earthy metals, as its oxide is of the type RO, as originally established by Berzelius, and its atomic weight must therefore be taken as 13.65.

AUSTRALIA AND POLYNESIA. I. GENERAL STATISTICS.-The area (in square kilo

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An intercolonial conference of statesmen convened in Sydney, in January, to consider in what particulars and by what methods federal action would at the present time be desirable. It was the continuation of a conference which was held in Melbourne in the latter part of 1880, which discussed an arrangement regarding the border customs between New South Wales, Victoria, and South Australia. Those three colonies alone participated in the former conference. In the present one all the colonies were represented, informally, by prominent administrative officials. It was composed of the following members: Henry Parks, Colonial Secretary of New South Wales, chairman of Conference; Graham Berry, Chief Secretary, and William M. K. Vale, Attorney-General, Victoria; James Watson, Colonial Treasurer, New South Wales; Thomas Dick, Colonial Secretary, New Zealand; William Morgan, Chief Secretary, and C. Mann, Treasurer, South Australia; A. H. Palmer, Colonial Secretary, and Boyd D. Morehead, PostmasterGeneral, Queensland; W. R. Giblin, Colonial Treasurer, and W. Moore, Colonial Secretary, Tasmania; Chief-Justice Wrenfordsley, Western Australia.

The final federal union of the Australasian colonies has been looked forward to since the

The movement of population in the several release of the principal colonies from crown colonies was as follows in 1878:

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administration alike by British and colonial statesmen. Confederation might have been accomplished with less difficulty at the time when the right of self-government was first conferred, and before the development of divergent policies. The conflict of policies and diversity of laws since the growth of population and material prosperity has brought the colonies into closer contact afford the real incentive, while constituting a serious practical difficulty, to the movement, which has been begun, toward conformity and federation.

The greatest actual obstacle in the way of a

The financial condition of the colonies in federal union is the opposite commercial poli1879 was as follows:

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cies pursued by the two leading and contiguous colonies, Victoria and New South Wales. Victoria has lived ten years under a tariff framed for the encouragement of domestic industries, and her people tenaciously adhere to the protective idea. Her neighbor and rival, New South Wales, is equally attached to her revenue tariff, and the people are thoroughly devoted to free-trade principles. The less populous colonies incline to the British doctrine, and have constructed tariffs which do not differ

The commercial statistics for 1879 were as greatly from that of New South Wales, and follows:

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can, without friction, be brought into exact conformity. The Intercolonial Conference did not hesitate to attack the vital subject of a customs union, although an immediate agreement is out of the question. Amid the protests of Mr. Berry at the proposed "insulation" of Victoria, the conference voted that a joint commission be appointed by the autonomous colonies to construct a common tariff.* Vic

*West Australia is the only Australasian colony which

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