concomitant features of mountain corrugation; and in regions of such corrugation we should look for thermal wa ters. Designating upon a map the localities of the numerous. springs reported by Mr. Gilbert, the first thing noted is that the Mississippi Valley contains no hot spring, nor do the plains of the Atlantic coast. Among the Ozark Mountains of Arkansas we have one. In the Colorado Plateau five localities are noticed. The distribution of hot springs is found to coincide very exactly with that of corrugation. The range of temperature of the waters is far higher in the western region than in the eastern.-Hayden's Survey and Reports, 1876, 145.

CONNECTION BETWEEN SOLAR SPOTS AND TERRESTRIAL ELECTRICITY.

As the result of his study upon the frequency of thunder and lightning storms in Germany and Switzerland, Von Bezold concludes it probable that high temperature as well as a solar surface free from spots are the conditions bringing about years rich in electrical displays. Since, however, the maxima of solar-spot surface agrees with those of greatest intensity of the auroras, it follows that both kinds of elec trical phenomena, thunder-storms and auroras, are in a certain manner complementary to each other, so that years rich in thunder-storms are poor in auroras, and vice versa. Such a connection between sun-spots and thunder-storms implies, however, by no means the assumption of a direct electric interchange between the earth and the sun, but can rather be considered as a consequence of the variable solar insolation as dependent upon the solar-spot surface. The variations of insolation, according to Köppen, are not felt simultaneously, but rather successively in the various latitudes of the earth. The thunder-storms depend not only upon the temperature of the place of observation, but also upon the condition of the atmosphere at points far distant and belonging to other climatological zones, as is best seen in the thunder-storms accompanying extensive storms. In this way perhaps can best be explained the peculiar position which the curve of thunder-storm frequency holds between the solar-spot curve and the temperature curve.-Sitzb. K.-B. Akad. der Wissens., Munich, 1874, IV., 318.

THE FORCE OF SEA WAVES.

In connection with a memoir on the Manora Breakwater, read before the Institution of Civil Engineers, London, by W. H. Price, some remarks were made by Mr. David Stevenson and others on the effect of sea waves in breaking up heavy masses of masonry. A remarkable instance of the power of such waves was afforded in the case of the breakwater at Wick, on the coast of England. The height of the waves at this place was several times measured and estimated, the result being about forty-two feet from crest to hollow. Stones of eight and ten tons' weight were by such waves carried from the parapet to the top of the breakwater. It was resolved finally to construct the outward extremity of the breakwater by depositing three courses of one-hundred-ton blocks of stone on the rubble base, as a foundation for three courses of large flat stones, surmounted by a monolith of cemented rubble built on the spot. The end of the breakwater, therefore, was in substance a monolith weighing upward of eight hundred tons, being about 26 feet by 45, and 11 feet in thickness, cemented to the underlying rubble base. Incredible as it might seem, this huge monolithic mass succumbed to the force of the waves. was actually seen by the resident engineer to be bodily slewed around by successive strokes, until it was finally removed and deposited inside of the pier. In fact, not only the upper portion, but the three lower courses of stone, forming a mass of 1350 tons, were removed without breaking.-Minutes and Proceedings Institution of Civil Engineers, London, 1876, 40.

CLIMATE OF THE CAUCASUS.

It

Dr. Radde, in some remarks on the geology of the Caucasus, shows that the physics of the surrounding land is rendered entirely different by the presence of these great mountain ranges. The limit of perpetual snow in the Caucasus sinks to ten thousand feet in the moist districts of Colchis, but rises on the northern side of the Caucasus, where the dry east and northeast winds prevail, and where there can be only a slight precipitation of snow, until on Mount Ararat, even at the height of 14,300 feet, vegetation is found. There is, therefore, a difference of at least 4000 feet in the

limits of perpetual snow in different portions of the Caucasus. The culture of the vine succeeds without special protection in winter at an altitude of 3600 feet in Colchis, while on the east side of Mount Ararat, even at the height of 3000 feet, the vines must be protected in winter.

Over a hundred hot springs are known in the Caucasian range; and, according to Radde and Abisch, the distribution of these springs is independent of the extensive volcanic activity that exists in the former geological peaks. On the other hand, the springs as well as the volcanic phenomena are distributed in cognate methods along the dividing lines of axes of elevation and dislocation.

The most remarkable collection of mineral springs is at Pjatigorsk, where within the space of twenty-five square miles every possible kind of mineral springs is found: sulphur springs, alkali springs, iron springs, and muriatic-acid springs, all of which are abundantly visited by invalids.Sitzungsb. Ostpreuss, physikalisch-ökonom. Gesells., Königsberg, p. 8.

THE EASTWARD PROGRESS OF STORMS.

Robert Tennant, Esq., has endeavored to elucidate his views on the causes by which storms progress in an easterly direction. According to him the barometer rarely indicates the pressure due to the weight of the air directly above it; but owing to the sluggish currents at the surface of the earth and the rapid currents above, the pressure is diminished at the surface of the earth, although it may remain undiminished at higher altitudes. When in consequence of high winds the barometer falls, a spiral inflow then takes place toward the centre. This inflow is unequal on the different sides, being for Great Britain less on the east and northeast side, and greatest on the southwest side, in consequence of which the centre of the barometric depression moves eastward. As regards the truth of his statement that the barometer can not give a true indication of weight when the atmosphere is in motion, there can be no doubt; but the exact amount of the diminution of pressure, as calculated by well-known formulæ, is probably much less than that assumed by Mr. Tennant.-Proceedings Royal Society, Edinburgh, VIII., 612.

HAIL-STORMS IN FRANCE.

Sales contributes a pretty full study upon certain hailstorms which visited France in June and July, 1874, of which that which occurred on the 28th of July was especially remarkable. Two occurred on the 26th of June, covering quite distinct sections of country, between which there seemed good reason to believe that some connection existed, although its exact nature is not indicated by the theory. Very curious are the isolated points observed by him at which hail fell apparently without any connection with other more extensive hail-storms occurring at a distance. The principal object of his inquiry has been the connection between hailstorms and altitude above the ocean. In general the hail begins in the valleys, and rarely is observed at stations more than one thousand feet above the sea; which limit seems to offer insuperable obstacles to its formation in France, although not in America, where the heaviest hail-storms occur at higher altitudes.-Mém. Acad. des Sciences, Toulouse, 1875,

285.

RED SNOW ON THE PIC-DU-MIDI.

The establishment by the United States of meteorological observatories on Mount Washington and Pike's Peak seems to have stimulated the action of other meteorological offices in the same direction. Thus, in France, the observatory on the summit of Pic-du-Midi has formed quite an epoch in meteorological study. A number of interesting results, drawn from the first year's observations, are presented to the Academy of Sciences of Toulouse by Dr. Armieux, who specially calls attention to the hypsometric results, and to the peculiarly interesting phenomena of red snow. After a short historical survey of our knowledge of the red snow, to which he himself had previously contributed somewhat in his article "Topography of the Sahara," published at Algiers in 1865, he shows that the presence of red snow on the Pyrenees has been established beyond doubt. It has therefore thus far been observed both here and also in the Alps, Spitzbergen, Greenland, and New Shetland, and in the antarctic zone, to which we may also add an occasional record of its appearance in North America. From the draw

ings and description of the red coloring particles as seen under the microscope of Dr. Armieux, it is evident that with the red particles are mixed occasionally green ones; and the cryptogamous nature of the substance is placed beyond a doubt.

The explorers in the Swedish North Pole expedition have seen marine algæ growing and fruiting at a temperature far below zero, while at higher temperatures the spores completely disappeared. There are therefore some vegetables which can only live in intense cold and continuous dryness; and to these the cryptogams of the red snow must be nearly allied. Many of the figures observed by Armieux bear close analogy, he states, to those figured by Cohn in his beautiful memoir published at Breslau in 1872; whence he concludes an intimate relation between the Protoccocus nivalis and the Protoccocus pluvialis.-Mém. Acad. des Sciences de Tou louse, 1875, 195.

THE WINDS AND RAINS OF INDIA.

A valuable memoir on the winds of Northern India, presented by Henry Blanford, of Calcutta, to the Royal Society of London, has recently come to hand, in which this subject is treated of in the fullest and most admirable manner. He first describes the general scheme of the wind system of Northern India, in which he shows that it is very different from that of the adjacent seas. Instead of two monsoons from northeast and southwest prevailing alternately during about equal periods of the year, we find a great diversity of prevalent wind currents depending upon the direction of the mountain ranges and of the great valley plains; and with respect to period to be classified under three rather than two distinct seasons, excepting, indeed, in Upper Assam, where the normal monsoons prevail. In the cold weather months, from November to January, the wind appears to flow in a gentle current from a distinct source in the hilly regions southward, down the valleys of the Indus and Ganges, or across the water-shed of Central India. In hot weather the winds draw around to the westward, and dry currents radiate out over the whole region, and, becoming heated, form the well-known hot winds of April and May. These winds, however, are essentially diurnal winds. In June