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METEOROLOGY. 



cal stations in the White mountain region, 

 which will be equipped with suitable instru- 

 ments, and the records of which will be turned 

 over to the New England Meteorological So- 

 ciety for discussion. Of such stations reports 

 were made in 1886 from Berlin Mills, Quincy, 

 Shelburne, Stratford, and West Milan, K H. 

 The United States Signal Service has also a 

 station on Mount Washington. 



Fading out of the Red Sunsets. Prof. A. Ricco, 

 of the observatory at Palermo, in a commu- 

 nication to the Acaddemia dei Lyncei, on the 

 6th of October, 1886, remarked that the nor- 

 mal conditions in the matter of the red sun- 

 sets had at that time been resumed. The 

 means of all the observations, taken from the 

 beginning of the phenomena to 1885, indicated 

 a gradual diminution of intensity. Calling the 

 maximum, on the 3d of December, 1883, as 

 10, the mean intensity from December, 1883, to 

 April, 1884, was 5 '6 ; and from December, 

 1885, to April, 1886, it fell to 2'2. Bishop's 

 Ring had been invisible at Palermo, and also, 

 according to Prof. Tacchini, at Rome, for some 

 time. M. Ricco had perceived it, but very 

 faint, on the 15th of May; and its visibility 

 had since diminished. The author could not, 

 however, say that it had wholly disappeared, 

 for the clearness of the sky goes for a good 

 deal in his observations, and he had been able 

 to perceive it, under usually favorable circum- 

 stances, as late as the 19th of August. The 

 eruption of Ferdinatdea Island in 1831, and the 

 recent eruption of Etna, have contributed im- 

 portant facts to the study of the red sunsets and 

 the blue sun. The mass of vapors thrown up by 

 Ferdinandea was enormous, and comparable to 

 that which was launched from Krakatoa ; it 

 formed a column over the volcano at least fifteen 

 miles high. But no ashes were carried away by 

 the winds from Ferdinandea, because the sea- 

 water rushed into the crater after each eruption ; 

 and this explains the formation of such masses 

 of vapor. But, although there were no ashes 

 the phenomena of blue or green suns and red 

 twilights were observed over a great part of 

 Europe. Etna, .in its recent eruption, sent out 

 a column of vapor which, on the morning of 

 the 21st of May, was about eight, and in the 

 afternoon of the 24th, fourteen kilometres 

 high. Furthermore, ashes were thrown out, 

 which fell like a fine rain, at Reggio and at Pa- 

 lermo. For several days after the eruption, 

 the sun appeared rose-colored, but not green 

 or blue. The coloration was produced by the 

 volcanic dust in suspension, which intercepted 

 the rays of shorter wave-lengths. The red 

 twilights that were observed were, however, 

 but little marked. This may be attributed to 

 the lack of vapor thrown out by the volcano, 

 contrary to what took place at Ferdinandea 

 and Krakatoa, which were in immediate juxta- 

 position to the sea. The author believes that 

 we may regard the red twilights and blue or 

 green suns following grand volcanic eruptions 

 as caused, not by the ashes, but by the vapors. 



International Meteorological Congress. An In- 

 ternational Meteorological Congress met at 

 Biarritz, October 4, 1886, and was attended 

 by 1,100 members, among whom some eleven 

 or twelve countries were represented. Dr. 

 Durand-Faudel was chosen president of the 

 Congress, and delivered the opening address. 

 Numerous papers were presented ; among 

 them several relating to the climates of the 

 bathing and thermal stations of the south 

 of France. M. Teisserenc de Bort deliv- 

 ered an address on weather-prediction, in 

 which he estimated how far science had ad- 

 vanced in the effort to fix the laws by which 

 the development and changes of atmospheric 

 phenomena are governed. It seems to be es- 

 tablished that the most important factor in 

 determining the conditions of weather is the 

 distribution of centers of barometric depres- 

 sions, and that these are preponderantly con- 

 trolled by conditions of temperature. Hence 

 are deduced as fundamental rules: 1. That 

 whenever a region of considerable extent pre-t 

 sents an excess of temperature either absolute 

 or relatively to the temperature of other points 

 in the same latitude, there is a tendency to the 

 formation of a barometric minimum in that 

 region, which is manifested either by the ex- 

 istence of a close minimum, or by the flexion 

 of the isobars; and, 2. Barometric maxima, 

 points whence air escapes in all directions, 

 tend to be established in the vicinity of regions 

 where the temperature is low, either absolutely 

 or relatively to the latitude. By the operation 

 of these rules, winds move from zones of high 

 pressure toward the points where the barome- 

 ter is low. Hence, also, the points of relative 

 cold or high pressure, and of relative heat 

 or low pressure, have been designated grand 

 centers of atmospheric action. The shift- 

 ing of these centers, which is always taking 

 place to a certain extent, and occasionally oc- 

 curs in a marked degree, may be regarded as 

 the occasion of those anomalies of season 

 which are sometimes remarked. The con- 

 tinued study of weather-prediction, then, in- 

 volves a more complete study of the general 

 circulation of the atmosphere, in order to 

 ascertain the causes of the normal repartition 

 of the centers of action; the determination of 

 the effects of displacement of the centers on 

 the meteorological elements wind, temper- 

 ature, rain, moisture, and cloudiness and the 

 discovery of the causes of the displacements of 

 the centers of high and low pressures from 

 their normal positions. Another series of 

 abnormal phenomena, which seem to be of 

 regular occurrence, like the May frosts and 

 the Indian summer, invite study, the object of 

 which should be to ascertain whether they are 

 really periodical, and whether they are con- 

 nected with some direct solar action or with 

 extra-terrestrial phenomena of some other pe- 

 riod than that of the earth. The author is 

 hopeful that with the extension and the com- 

 plete systematization of weather observations, 



