sketched. The great brick-red oval spot, first seen in 1878, is still faintly visible. It is 30,000 miles in length and 7,000 miles in breadth. Its persistence of form is not the least remarkable feature. For years it had a translatory motion of its own, which has now ceased. It is doubtful if photography will ever avail us much, as the image of the entire planet on the negative plate would be only one sixteenth of an inch in diameter, and of course details would be microscopic. Jupiter's fifth satellite was measured on Feb. 27, 1897, by Prof. J. M. Schaeberle at the Lick Observatory, the places agreeing with Marth's ephemeris fairly well. From long-continued observation of Jupiter with the Göttingen heliometer, Prof. Schur has determined the values for the equatorial and polar diameters of the planet to be 37-42" and 35:13" respectively. The apparent diameters generally adopted by astronomers are 49.9" in opposition and 304 in conjunction, or 40·15" at mean distance. His diameter is usually given as 87,900 miles, and his spheroidity about or 5,500 miles, surpassing in this respect all the planets except Saturn."

Comets. Swift's periodic comet was not found on its return in January, 1897. As its period is five and a half years it, like nearly all others having a fractional year period, can only be seen at alternate returns to perihelion, as the half year brings the Sun in the neighborhood of the comet.

Comet f 1896 (Perrine's).—This periodic shortperiod comet is another addition to the long list of Jupiter comets. It was discovered by Perrine at the Lick Observatory on Dec. 8, 1896. It had a starlike nucleus and a tail 30' in length. Like all shortperiod comets, except Encke's, it was not visible to the naked eye. Its elements, except in one particular, bear a close resemblance to those of the long-lost divided Biela's comet. The elements of both are placed side by side for comparison:

Comet 1897 I (Perrine's).—This comet's orbit is a parabola, and therefore it appeared for the first and last time, as only comets moving in elliptical orbits can ever visit our system the second time. Its elements are as below. It was discovered Nov. 2, but reckoned in the order of perihelion passage, instead of date of discovery, it becomes Comet I 1897. Perihelion passage, 1897, Feb. 8-1762, Berlin mean time; node to perihelion, 172° 20′ 59.7"; longitude of node, 86° 17′ 511"; inclination, 146° 8' 24.9"; perihelion distance Earth = I, 1062254.

D'Arrest's Comet.-This long-known short-period comet was found at the Lick Observatory by Perrine on June 28, 1897, in right ascension 30° 11' 9", polar distance 83° 46' 29". This is its seventh return since its discovery by D'Arrest in 1851. It is the faintest of all the short-period comets and often escapes detection, though always carefully and systematically searched for.

The Bulletin Astronomique" for March, 1897, contains a thorough investigation by L. Schulohf of the orbit of Comet Swift 1895 II previous to 1884. He had previously suggested the probable identity of the comet with that of Lexell, and requested astronomers to obtain as long a series of observation of it as possible, in order to obtain its elliptical elements with the utmost accuracy. Those made at the Lick Observatory extended over five months and enabled the elements to be ascertained

with considerable accuracy. The daily motion is 490-51 and the period 7.2043 years. The probable error of daily motion is only half a second of arc, making an error in the period of only three days; but, small as it is, it prevents the accurate computation of the perturbations by Jupiter back to the year of Lexell's discovery in 1779, since which time it has been lost. Even in 1838 it is impossible to say within forty days when the comet was at any assigned point of its orbit. Until this comet has been observed at another return it can only be assumed that the identity of the comet with Lexell's is very probable. It may be again visible in 1902, but it will be very faint and in considerable south declination. If it then escapes detection there is no hope of seeing it before 1931.

Gegenschein. This is an exceedingly faint circular patch of evenly diffused light seen by the naked eye only, always in the zodiac and opposite the Sun or 180°. Its diameter varies somewhat, being generally about 20° in diameter, and sometimes as much as 25°. Dr. E. E. Barnard sees a zodiacal band 3 or 4° in width extending from it to both the morning and evening zodiacal light. He has been assiduous in its observation for many years, as has also Prof. Searle, of Harvard College Observatory. Barnard has recently described in "Gould's Astronomical Journal," No. 403, May, 1897, its various appearances as follows: "When first seen in autumn it is unaccompanied by a zodiacal band, but later, when its right ascension is 0h 0m, it becomes elliptical and the band appears extending to the apexes of the evening and morning zodiacal light. There appears at different times an oscillation east and west of about 1°, with a tendency to a less longitude than 180°. It is impossible to explain on any hypothesis the cause of this light or counterglow, as it is often called.

The writer of these notes, after much reflection resulting from his own observations, suggests the following as the cause of the Gegenschein-viz., that it is caused by refracted and reflected sunlight precisely in the same manner as the red Moon when totally eclipsed. The sunlight passing tangentially through the Earth's atmosphere, which forms the boundary between sunlight and darkness, is refracted down upon the Moon and then feebly reflected to the Earth, rendering her visible, although totally immersed in the Earth's shadow. In this case it is the Moon that is the reflector, but in the case of the Gegenschein it is cosmic dust that is the reflector. That our atmosphere, and indeed all space, is impregnated with dust, is conceded by all astronomers. That the light is always opposite the Sun is a significant point in favor of this hypothesis. The subject is attracting increased attention, and there is hope that the cause of this strange phenomenon may be satisfactorily explained.

Zodiacal Light.-Another phenomenon, equally inexplicable and perhaps indirectly allied to the Gegenschein, is the zodiacal light, visible as a broad conical luminous beam in the west after sunset during the autumn and winter months and in the east before sunrise during the spring months. The spectroscope has recently shown that the light is sunlight reflected from some kind of noncoherent matter in the solid form. It has been seen circling the sky from the western to the eastern horizon, and must be treated, therefore, as a luminous ring circling the Earth instead of the Sun.

Unification of Time.-The international unification of time has been adopted in nearly every country except France, Spain, and Portugal. England, Belgium, Holland, and Luxemburg use western European time. Central time is adopted by Italy, Switzerland, Germany, Denmark, Norway, and Sweden. Russia, Roumania, Bulgaria, and Euro

pean Turkey use eastern time. In Natal, Australia, New Zealand, and Japan the time zones used are eight, nine, ten, and eleven hours fast of Greenwich. Canada and the United States use four time zones, four, five, six, seven, and eight hours slow of Greenwich time. Since May, 1897, Belgium has reckoned time continuously from 0 to 24h that is, the next hour after noon will be thirteen o'clock.

Largest Spectroscope. The largest spectroscope in the world has just been completed by John A. Brashear, of Allegheny, Pa., for Dr. Hans Hauswaldt's Astronomical and Physical Observatory, Magdeburg, Germany. It is 21 feet long and requires for working it a room 28 feet square. The size of the grating is 6 inches, and it is ruled with 18,333 lines to the inch, between which there is no difference greater than three millionths of an inch. It reveals in the solar spectrum over 2,000 lines belonging to iron. In the infancy of spectroscopy the sodium line (Fraunhofer's D) was considered single, which the spectroscope of to-day doubles, called D. This mammoth instrument shows each to be double and so wide apart are the pairs that 15 lines are revealed between them. Some of them, and perhaps all, may turn out to belong to our atmosphere. It also doubles the famous helium line, or D. The spectrum of the Sun has been photographed by it to 60 feet in length, crowded with lines from end to end. It is so arranged that, no matter what part of the spectrum is desired to be photographed, the negative plate is always in focus. The following method of photographing the solar spectrum and that of other heavenly bodies can not fail to settle many disputed points and may originate as many new ones as it settles. Suppose it is desired to ascertain whether any terrestrial substance, say calcium, is in the condition of a gas in the Sun's atmosphere: The sunlight is turned into the slit of the spectroscope, narrowly closed for sharpness of the lines to be photographed, and photograph the center of the Sun on the center only of the negative plate. An opaque bar is now placed over this part of the plate. The electric are light, in which has been placed in the concavity of the lower carbon pencil a small piece of calcium, is turned on the slit and the spectrum of calcium is photographed on each side of the opaque bar. When the plate is developed there is a picture on which the calcium spectrum with its lines is shown, and if there be any in the Sun's spectrum they can in a moment be identified by their coincidence. If this be the case we know that calcium exists in the state of vapor in the Sun's atmosphere.

Yerkes Observatory. The largest and most powerful refracting telescope in the world has recently been successfully mounted in the Yerkes Observatory, at William's Bay, Wisconsin, near the shore of Lake Geneva, 75 miles north of Chicago. The glass, 40 inches of clear aperture, has been by experts pronounced of superior excellence and has been received by the trustees. Much is expected of this gigantic telescope, which, from some discoveries already made and reported, will not disappoint the generous donor, Charles T. Yerkes, of Chicago, The following data will give the reader something of an idea what the making and mounting such a telescope in time, skill, labor, patience, and money means. The amount of the latter, including the observatory, was more than $1,000,000. The two disks of crown and flint glass, 41 inches in diameter, each free from striæ, bubbles, and inequality of density, cost in Paris, in the rough, about the shape of two large, thin grindstones, $40,000. Four years were spent by the late Alvan G. Clark, at Cambridgeport, Mass., in grinding them to the right curves and polishing them. The clear available aperture is 40 inches, and so perfect are the figures

two

of the four surfaces that every ray of light from a star falling on the great disks is refracted and dispersed by the crown disk and again oppositely refracted by the flint to a very small point. The price of the completed objective, as an object glass is called, with its cast-iron cell, was $100,000. It weighs 1,000 pounds. The outer crown lens is 24 inches thick at the center and inch at the edge, and weighs 200 pounds. The heavy flint-glass disk is 2 inches thick at the edge and 1 inch at the center, and weighs over 300 pounds. The glasses in their cell are 83 inches apart. The resulting focus of the combined lenses is 66 feet. The tube is of sheet steel, 64 feet long and 52 inches in diameter at the middle, tapering toward the ends, and weighs 6 tons. The pedestal and head, which are of cast iron, rise to a height of 43 feet, and weigh 50 tons. A winding staircase ascends to the driving-clock room and reading circles and to the balcony surrounding the head. The polar axis is of steel, 15 inches in diameter, 13 feet long, and weighs 3 tons. The declination axis is also of steel, 12 inches in diameter, 114 feet long, and weighs 1 ton. The driving clock weighs 1 ton, and is wound automatically by an electric motor. A double conical pendulum controls the driving clock, and is geared to the main driving wheel, 8 feet in diameter, which, together with the tube, weigh 20 tons, driven in exact sidereal time. circular floor, 75 feet in diameter, is raised and depressed 25 feet by an electric motor by simply touching a button, so that a high observing chair is not required. The center of motion of the telescope is 70 feet from the floor. The dome is the largest in the world, and weighs 70 tons.

The

Publications. - Harvard College Observatory has lately published two volumes of its annals, one concluding the zone observations, which has extended through Vols. XV, XVI, XXV, XXXV, and the one just issued, XXXVI. The other is devoted to a description of the spectrum of bright stars photographed with the 11-inch Draper telescope, and discovered by Miss A. C. Maury. Two hundred and fifty pages of Vol. XXV are devoted to discussion of the proper motions of the stars, deducible from the observations. In a series of preliminary notes she has discussed the relation of the spectra of the Orion stars to that of helium.

Prizes. The following prizes have been awarded to astronomers since the last report: The Laland prize of 540 francs was awarded to M. Puiseux for his selenographical work. The Valz prize was bestowed on M. Possert for the reduction of old observations previously inaccessible. The Janssen prize was given to M. Deslandres for his studies and investigations in spectroscopy. The Mrs. JacksonGwilt medal, of the Royal Astronomical Society of England, was awarded for the first time to Dr. Lewis Swift, of the Lowe Observatory, Echo Mountain, California, for his numerous discoveries of comets and nebula. It consisted of a large bronze medal and $125.52 in cash. The prizes of the Paris Academy of Sciences have been awarded as follows: The extraordinary prize of 6,000 francs has been divided between M. Darrions and to M. Banle, for the application of the gyroscope to determine the altitude of the stars at sea. M. Faye, the distinguished astronomer of France, has been awarded a gold medal by the Paris Academy, in honor of his jubilee, he having been elected a member in 1847. The Royal Astronomical Society of England bestowed its gold medal on Dr. E. È. Barnard for the discovery of the fifth satellite to Jupiter, and other important discoveries in astronomy. The German astronomer Prof. Dr. Arthur Auwers, has received from the German Emperor a gold medal for his services to science, especially to astronomy.

rays and not high temperatures which exert this bactericidal action. That these matters are of importance in limiting the life of bacteria in our streets and rivers, and that the sun is our most powerful scavenger, has been shown." The speaker emphasized the need of recognizing that bacteriology only touches animal pathology at a few points, and of the public learning that, so far from bacteria being synonymous with disease, the majority of these organisms appeared to be beneficial rather than inimical to man. Cases were cited as pointing to the conviction that a school of bacteriology which had nothing to do with medical questions, but investigated problems raised by the forester, agriculturist, and gardener, the dairyman, brewer, dyer, and tanner, etc., would yet be established in connection with some great botanical center. The speaker then went exhaustively into the discoveries regarding the exact relation of bacteria to the various methods of cheese and butter manufacturers, and pointed out the value of the researches of many well-known scientists in this subject. Prof. Ward next dealt with the action of fungi upon the roots of forest trees, and then explained the nature of researches and the nitrifying organisms found in manure and soils. With respect to these it was shown that there now exists a sketch of the whole of the down grade of the cycle of organic nitrogen in Nature; it only needs supplementing by the history of the fixation of free nitrogen from the atmosphere by leguminous plants and certain soil organisms to complete the sketch. In conclusion, he dealt with wheat rust and the use of manure.

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Among the more important papers read before this section were the following: "On the Mycelium of a Witches' Broom Fungus," by P. Magnus; "Stereum Hirsutum: A Wood-Destroying Fungus," by H. Marshall Ward; "The Nucleus of the Yeast Plant," by H. Wager; "A Disease of the Tomatoes," by W. G. P. Ellis; "The Chimney-shaped Stomata of Holocantha Emeryi: Some Consideration on the Functions of Stomata" and "Distribution of Nebraska Trees," by Charles E. Bessey; "On the Species of Picea in Northeastern America," by D. P. Penhallow; "Contribution to the Life History of Ranunculus," by John M. Coulter; Vegetation of the Region of the Prairie Province," by Roscoe Pound and F. E. Clements; "The Zonal Constitution and Distribution of Plant Formations" and "The Transition Region of the Caryophyllales," by F. E. Clements; 'Note on Pleurococcus," by Dorothea F. M. Pertz; "Spermatozoids of Zamia Integrifolia," by H. J. Weber; Diagrams illustrating the Result of Fifty Years' Experimenting on the Growth of Wheat at Rothamsted, England," by H. E. Armstrong; "Preliminary Account of a New Method of Investigating Stomata," by Francis Darwin; "Notes on Lilæa," by D. H. Campbell; "Lecture on Fossil Plants," by A. C. Seward; "On the Existence of Motile Antherozoids the Dictyotacea," by J. L. Williams; "Insemination in Ferns and "On more than One Plant from the Same Prothallium," by E. J. Lowe; "Results of Some Experiments in Cross Fertilization," by W. Saunders; "On a Hybrid Fern, with Remarks on Hybridity," by J. B. Farmer; "Morphology of the Stele in Vascular Plants" and "The Gametophyte of Botrychium virginianum," by E. C. Jeffrey; "Remarks on Changes in Number of Sporangia in Vascular Plants," by F. O. Bower; Notes on Fossil Equisetacea," by A. C. Seward; "On Streptothrix actinomycotica and Allied Species of Streptothrix," by E. M. Crookshank; "Observations on the Cyanophycea," by H. B. Macallum.

Also the following reports were presented before

the section: "On the Preservation of Plants for Exhibition and "On the Fertilization of the Phæophyceæ." On Aug. 24, as previously noted, this section met in joint session with Section I. Popular Features.-On Aug. 19 their Excellencies the Governor General of Canada and the Countess of Aberdeen gave an evening reception to the officers, members, and associates of the associa tion in the legislative building. The first evening lecture, on "Canada's Metals," by Prof. W. C. Roberts-Austen, was delivered on Aug. 20. On the evening of Aug. 21 a lecture for the workingmen of Toronto, on "British New Guinea: The Country, its People, and the Problems which the Region offers to Naturalists and Geographers," was given by Dr. H. O. Forbes. Special sermons were preached on Aug. 22 in St. James's Cathedral by Bishop Sullivan; in St. James's Square Presbyterian Church by President Patton, of Princeton University; and in St. Michael's Cathedral by the Rev. P. A. Halpin and the Rev. Father Ryan. The usual devotional service of the association was held in the university on Sunday under the direction of the Rev. Principal Sheraton. The second evening lecture was on "Earthquakes and Volcanoes," and was delivered on Aug. 23 by Prof. John Milne. The usual conversazione was given by the local executive committee in the university building on Aug. 24. On Aug. 25 a dinner was given in honor of Lord Kelvin, Lord Lister, and Sir John Evans in the pavilion of the Horticultural Gardens. Two interesting ceremonies during the week were the convocations of the University of Toronto on Aug. 20, when the honorary degree of LL. D. was conferred on Lord Kelvin, Lord Lister, and Sir John Evans, and that of the University of Trinity College, on Aug. 24, when the honorary degree of D. C. L. was conferred on Sir John Evans, Lord Kelvin, Lord Lister, Sir William Turner, James H. Bryce, and Sir George S. Robertson. The afternoon entertainments included garden parties, several of which were held on each afternoon during the week. In addition to the foregoing, a series of four special excursions -as follow: To Niagara river, Niagara Falls, and return; to Muskoka and return; to Penetanguishene and return; and to Hamilton, Niagara Falls, and return-were arranged for Aug. 21; and subsequent to the meeting the following excursions were provided for: To Toronto, Ottawa, Ottawa river, Montreal, and return; Toronto, Kingston, St. Lawrence river, Montreal, and return; and Toronto, Parry Sound, Algonquin Park, Ottawa, Montreal, and return.

Attendance and Grants.-At the concluding meeting, held on Aug. 25, it was reported to the association that those in attendance at the meeting comprised 120 old life members, 8 new life members, 286 old annual members and members of the American association, 125 new members, 682 associates, 100 ladies, and 41 corresponding honorary members. Total in attendance at the association's meeting, 1,362.

A report from the Committee on Recommendation, setting apart grants to the amount of £1,350 for scientific investigations, was adopted. The grants were as follow: To establish a meteorological observatory on Mount Royal, £50; to further investigate the fauna and flora of the Pleistocene beds in Canada, £20; the collection, preservation, and systematic registration of Canadian photographs of geological interest; the biology of the lakes of Ontario, £75; the northwestean tribes of Canada, £75; to organize an ethnological survey of Canada, £75; the establishment of a biological station in the Gulf of St. Lawrence.

Next Meeting.-The association will meet in 1898 in Bristol on Sept. 5-17, and for the presi