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side northward or on the south side eastward. The most of the centres of low pressure that follow the north coast of Norway turn east and southeast and pass on to the north of Nova Zembla into Russia. The other important stormpath is up the east coast of Greenland, west of Iceland, Jan Mayen, and Spitzbergen, then suddenly eastward to the north coast of Nova Zembla. The storms that pass up the west coast of Greenland are not felt at all on its east coast.
Mühry (Petermann's Mittheilungen, 1877, § 21), from the study of three westerly storms in Europe in 1873 (i. e., January 23, March 11-13, December 16-19), concludes that these represented great equatorial currents penetrating from the Atlantic eastward deep into the interior of the cold region of Asia.
OPTICAL PHENOMENA. The application of the spectroscope to the study of the atmosphere continues to be urged in a desultory way by Professor Smythe, who notes the occurrence of a severe rain on August 21, 1877, “marked by a heavy rain band in the prismatic spectrum of the daylight.” The studies of Hennessey upon the atmospheric bands at the time of sunrise and sunset give, however, the proper clue as to the best method of making and utilizing this class of observations.
In discussing a large number of accurate observations of the scintillation of the stars, Montigny is led to the conclusion that the intensity of this phenomenon increases with the approach of rainy weather or moist weather at all sea
The increase is noticeable one or two days before the rain arrives, and diminishes immediately after the rain ceases. When a barometric depression with strong winds passes near the observer, the scintillation is remarkably increased.
Lommel, after calling attention to the knowledge possessed by Biot, Brewster, Goethe, Arago, and Billet in reference to the polarization of the light of the rainbow, shows that the so-called Cartesian angle of incidence is that for which, for every substance and every color, according to Fresnel's theory, one ninth of the light polarized perpendicular to the plane of incidence will be reflected. For the whole rainbow the effectual rays are those that possess the maximum polarization. For a single prism the angle of minimum deviation corresponds to that of minimum polarization.
ELECTRICAL PHENOMENA. Dr. Munk, of Marburg, quotes a sentence from the Talmud (Tosefta, Sabbath VII.) showing that in the fourth and fifth centuries before Christ the use of the lightning-rod was understood. Dr. Wiedemann adds that, according to Dumichen, the Egyptians gilded and coppered the highest projections, etc.,“ in order to protect from the celestial lightning.”
The protection of buildings from lightning has been treated of recently by the eminent electrician J. C. Maxwell, who elucidates the idea, already defended in these pages, that a discharge cannot occur between two points within a building if the exterior is surrounded by a metal cage or sheathing, which latter need not be connected with the ground, but must, however, be joined to the gas or water pipes, in case any such enter into the building from without.
In a memoir upon the aurora of April 7, 1874, published in the report of the Chief Signal Officer for 1876, the author concludes that the auroral light emanated from a very low region in the earth's atmosphere, and spread east and west from certain well-marked localities.
An elaborate paper by Mann is reprinted with additions in the Papers on Professional Engineering.
RELATIONS WITH SUN-SPOTS. The connection between solar-spot frequency and terrestrial phenomena has continued to receive some attention during the year, but not much progress has been made by the advocates of an intimate connection. Meldrum reports that the cyclones of 1876 in the Indian Ocean exhibited markedly diminished intensity, in accordance with his theory; Hunter, Hill, and Archibald have shown that the registers for different parts of India may be so construed as to lend plausibility to the idea that years of maximum and minimui rainfall follow the years of maximum and minimum sun-spot activity. The importance of the question in India is acknowledged in view of the disastrous famines that visit that land, and the British Government has been urged, through the London daily press, to institute a comprehensive system of hydraulic engineering, such that the surplus rains of one season may be husbanded for use in time of need. Such a system was a thousand years ago in full operation, both in India and Ceylon, but has long since fallen into neglect.
Balfour Stewart has a very excellent paper in the proceedings of the London Royal Society, concluding that there is a slight balance of evidence in favor of a connection between atmospheric and solar phenomena.
Professor Langley, of Pittsburgh, as the result of a careful approximate calculation of the direct effect of sun-spots on terrestrial temperatures, shows that the least change in the mean annual temperature of the globe in the course of an eleven-year spot period is not less than one twentieth of a degree centigrade, and the greatest change is not greater than three tenths of a degree. In this estimate he only considers the direct effect of the diminished radiation of the spots, and can conclude nothing as to other, perhaps more important, changes, of which the spots are merely accompaniments.
RELATIONS WITH METEORS. The meteors that encounter our atmosphere certainly communicate to its upper layers the heat due to the sudden stoppage of their motion, but of the exact amount of this heat we have but very indefinite ideas. A contribution to our knowledge of this subject has been made by Govi.
A remarkable meteor was visible from Kansas to New York on the evening of the 21st of December, 1876, and approximate determinations of its movements have been published by Kirkwood, Abbe, and Newton; the latter states that previous to encountering the earth's atmosphere it must have been coming from a point near to and a little south of the ecliptic, in the southern or eastern part of the constellation Capricornus; he solicits additional observations from those who saw this meteor, as he hopes to continue his study thereupon.
CLIMATOLOGY. The climate of Chili is treated by Hann in an excellent résumé of the volumes of observations published by the Central Meteorological Office at Santiago, 1868 to 1872. The last volume is, he says, the most complete meteorological annual report that has as yet appeared from any part of America.
The climate of the Fiji Islands, as based on meteorological observations made during five years by R. S. Holmes, is the best account we as yet have seen of the climate of any of the South Pacific islands. The mean annual temperature is 79°, the highest 98°, and the lowest 58°; the number of rainy days 170 per year, and the annual rainfall 124 inches. The climate is a healthy one as compared with most tropical countries. Uniform northeast trades prevail.
Chambers, of Bombay, communicates to the Royal Society a memoir on the meteorology of that part of India, in which, after giving the results of twenty-seven years of observation, he discusses the relation of the facts thus presented to the present state of theoretical or deductive meteorology.
Dove has published his annual volume of monthly and five-day means for Prussian, Austrian, Swiss, and Italian stations.
Mr. C. Todd has published a work on the climate of South Australia, which is highly spoken of. He has at his disposal seventy rainfall stations, from which also weather reports are received. He finds that barometric changes progress eastward, occupying from two to four days in passing from Western Australia to Adelaide, and from twenty to forty hours in passing thence to Sydney and Brisbane, on the east coast.
The climate of Yarkhand forms the subject of the first of the Indian memoirs by Blanford, and introduces uso to one of the most interesting spots on the globe. At an elevation of 4000 feet its temperature is that of Gibraltar and Messina in summer, but of Stockholm in winter. A high, thick haze of fine sand-dust replaces the clear skies of other parts of India.
Woeikoff gives in the Vienna Zeitschrift for November 1st, 1877, a sketch of the climate of inner Asia, based principally upon the recent explorations of Przewalski and Pylzof, who journeyed in Thibet, Mongolia, China, Gobi, and Alaschan.
Plantamour has published in one fine volume “Nouvelles Études sur le Climat de Genève," embracing a discussion of the observations since 1826.
The climate of Peking has been thoroughly worked up from twenty-three years' observations in a memoir by Fritsche. The temperature of Peking, as shown by observations in 1757-62, has not sensibly changed in 100 years.
The meteorological observations made at Abbasie, near Cairo, under the direction of Ismael Bey, have, we believe,
never as yet been published in full, but an interesting collation of such as have been made accessible to meteorologists has been compiled by Hann. The observations extend from 1868 to 1874, and are made eight times daily (at 0, 3, 6, 9 o'clock, etc.).
The diurnal and annual periods of the meteorological data for Cracow, as deduced from observations during 1867 to 1873, have been published by Dr. Karlinski.
The climate of Kerguelen Island, on the 49th parallel of southern latitude, has been approximately deduced by Hann from the collected results of observations made there by Ross in 1840, Cook in 1776, and the German Transit of Venus Expedition, 1874 – 75. On comparison with other points in the southern hemisphere, he finds this island to have an abnormally low mean annual temperature.
The climate of Switzerland is well presented by Billwiller in the means from twelve years of observations at the normal stations in that country.
The nations that have published their climatological data in accord, or nearly so, with the form recommended by the Vienna Congress, are as follows: Italy, 24 stations; Netherlands, 4 stations; Great Britain, 9 stations.
Wild has published, as a supplementary volume to his Repertorium, the first two sections of a great work on the distribution of temperature in the Russian Empire. These sections deal with the diurnal periodicity and the reduction of isolated observations to daily means. The subject is handled with great clearness and discretion, and will be a model for many future investigators.
HYPSOMETRY. A year ago there was published a memoir by Grassi, of Milan, on "Barometric Hypsometry," in which he drew attention to the formula of Saint-Robert, published in the Philosophical Magazine for 1864, and in tabular form in the Memoirs of the Academy of Turin, Vol. XXV. This formula is based directly upon Glaisher's balloon observations, and, according to Grassi, gives most excellent results; but in a very interesting paper by Hartl it has been recently shown that the Saint-Robert formula gives altitudes decidedly too small throughout the year, at least for Mount St. Bernard,