Something analogous occurred in 1824 and 1825. The terrible inundation of the Rhine in the autumn of 1838, the overflow of the Neva at St. Petersburg, the gales from the S..W., which, according to the observations of Munk e and Schubler, took place in Schlesvig, and in all Holstein, are a proof of this. The barometer oscillated incessantly, and the rains were so abundant that every where, but principally in south Germany, springs burst forth in the streets and squares of the towns. In the same year the mean for the winter months was very high. In Iceland, on the contrary, according to Thorstensen's observations at Reikiavig, the mean of December was several degrees below the ordinary mean, and the barometer was very high, whilst it was very low at Copenhagen. This year, which was so rainy in Europe, was very dry in India; for at Bombay the quantity of rain was 118 centimetres below the mean. In Africa, it appears that there were violent gales; for, in the night of January 19th, 1825, the English ship, Clyde, being 100 myriametres from the coast of Africa, was covered with fine sand, which the east winds had brought from the desert. In east Africa, Ruppel experienced violent storms: phenomena which are very rare in these countries, as may be discovered from the fear of the inhabitants. Ley experienced the same thing in Upper Egypt. In the following summer, all the north part of tropical Africa was a prey to excessive drought, and the inundation of the Nile having failed, there was a complete dearth.

The same disturbances were manifested on the two shores of the Great Ocean. In California, there were violent tempests during the autumn, as there were also at the Sandwich and Philippine Islands. But the trade-winds were no longer blowing regularly over the sea. facts prove that the anormal phenomena of Europe are not isolated, but are propagated over the whole circumference of the globe.

These

In order to demonstrate this truth, I will further relate the following observations. We know that the winter of 1829-30 was one of the coldest that had occurred in Europe for a long time; this same winter was so mild in America, that there was no ice on the west coast: which permitted Captain Ross to advance so far to the north.

The mildest winter that we have had for a long time was that of 1833-4, but it was preceded by violent disturbances. From the commencement of July, the S.W. winds prevailed in almost the whole of Europe. They were frequently of extreme violence, especially at the end of August and be

ginning of December; the journals were filled with news of shipwrecks on the coasts of France and England. In the Alps there were tempests; and such masses of snow and such quantities of rain fell, that the inhabitants were forced to take refuge in the plains with their flocks. From the beginning of September violent gales were experienced in the sea of the Antilles, and at Nova Zembla. În India, in Brazil, and Guiana, the drought was so great, that very many of the inhabitants died of hunger. In China, there were terrible inundations; but the swelling of the Nile was quite insignificant. The contest between the south and the north winds was renewed several times in the course of the autumn; the former always prevailed; and the wind rarely blew from the east for several hours together. Abundant rains fell in January; the rivers overflowed their banks. The south winds extended over to the region of the trade-winds; and ships were delayed in their voyage from France to Demerara. The thermometer rarely fell as low as zero; trees put forth their buds in the month of January, and many species remained in blossom throughout the winter around Halle, I observed the Lamium purpureum, several species of Crepis and the Thlaspi arvense. But we shudder on reading the description given by Captain Back of the cold he endured in his expedition across the north countries of North America. In the United States, and in Persia, the winter was also extremely rigorous. During this conflict of land and sea winds, the barometer in Germany did not deviate much from its mean height; but it oscillated considerably. The weather was rough and disagreeable, and quite in contrast with the mild temperature of the preceding winter. Finally, the east winds predominated the sky became serene, and the sun was able to warm the earth. It seldom rained; and there was a general drought throughout Europe. Meanwhile, the west winds. several times strove to obtain the sway in the atmosphere; but, during the contest, there were violent storms, such as those of the 5th and the 21st of July. On the 21st of July, the barometer began to fall; the sky was still of great purity, because these south winds dissolved all the fogs; but, on the morning of the 21st, the cirri began to multiply. In the afternoon, a violent storm formed: west winds prevailed above; in the lower strata, all the vanes indicated an east wind. Thick clouds extended from the west to the east, whilst all the cumuli moved from east to west. In proportion as the west wind gained the lower levels, the vapours were precipitated; but the east wind incessantly

drove them back. The storm was accompanied with hail and rain. This contest took place in a straight line that passed above Halle, and was directed north and south; for several days this contest was renewed, and its issue was uncertain.

But, like as currents of waters, flowing in opposite directions, produce whirlpools, so there were in this case very abundant local showers. Finally, on the 26th of July, the east wind obtained the mastery at Halle, and drove back its antagonist. On the 27th, the barometer rose; the weather again became fine, but in the evening there were violent storms on the borders of the Rhine. On the 29th, Holland and the north of France were the theatres of this contest, and, on the 30th, a violent storm burst over England. For the space of a month the east winds maintained the weather fine, and obtained the mastery in a contest that had commenced in the Alps on the 25th of August, and, by the 27th, was propagated as far as the north of Germany. They then prevailed without interruption until the middle of October, when the west winds prevailed in their turn, after gales that had lasted several days, and changed the physiognomy of the weather. Whilst in Europe the summer was remarkably dry, the swelling of the Nile was considerable, and violent storms inundated India and China.

Such contrasts are not uncommon in Europe, and, in this respect, the Alps often form a remarkable limit; for they separate the climates of the north of Europe from the Mediterranean climates, where the distribution of rain is not the same as in the centre of Europe. Hence the differences between the climates of the north and south of France. If the winter is mild in the north, the newspapers are filled with the lamentations of the Italians and the Provençals at the severity of the cold. Not to multiply examples to no purpose, I will simply allude to the first months of the year 1838, which were so rigorous in Germany, France, England, and Russia. At Lisbon, on the contrary, the weather was rainy, but very mild; at Marseilles, the almondtrees were in bloom in the month of January; at Naples and at Algiers, the winter passed unperceived. But this proves that the Mediterranean climates alone were privileged; for, on the other side of the Apennines, at Bologna, and in Lombardy, where the climate resembles that of the rest of Europe, the cold was very intense.

Thus, then, a great fall of the barometer, or frequent oscillations of the column, prove that there are meteorological disturbances on the surface of the globe, and conflicts of opposite winds, which change the weather. Further,

when the barometer rises and falls rapidly, we may affirm that the weather will be variable for a long time. If we knew the weather that prevailed on the rest of the globe, we might conclude that which could be expected. We ought to know, when the barometer is low, whether the cold is very intense in America or in Asia. In the first case, the west winds will bring rain; in the second, the east winds will bring cold. However, on studying in the spring the barometer and the direction of the gales of wind, we may establish certain probabilities. If the barometer has fallen considerably during S.W. winds, and then rises slowly; if the wind passes from the west to the N.W., and remains in that direction; it is a proof of the predominance of west winds, and the weather will be influenced by them: we saw this in 1833. If the barometer, on the contrary, rises very quickly, and if the wind passes in a short space of time from the S.W. to the N.E., where it stops, we may expect a prolonged cold, like that which prevailed in 1829.

VI.

ELECTRICAL PHENOMENA

OF

THE ATMOSPHERE.

THERE are few men on whom thunder does not make a lively impression; the learned and the ignorant are equally struck with the grandeur of this phenomenon. The people whom the Europeans have discovered in past centuries regarded it as the sign of celestial anger, as did the Greeks and Romans. Also Jupiter Tonans was the greatest of the pagan gods; and in the Bible it is said that thunder is the voice of the angry Lord. Some philosophers of antiquity disputed this opinion; but this prejudice remained: and even in the present day we hear sermons in which the thunderbolt that falls on a house is considered as a punishment deserved by its inhabitants. Some ancients considered thunder as produced by emanations arising from the earth. This idea was adopted by many learned men; and, although Aristophanes ridiculed it in his comedy of The Clouds, yet the fear of the gods always served to weaken it in proportion as the doctrine of Epicurus was the more spread. This opinion still existing at the epoch of the revival of the sciences, thunder was compared to the explosion of a piece of artillery; and it was pretended that saltpetre and sulphur exist in the atmosphere. But, in the middle of the seventeenth century, Otto de Guericke having produced an electric spark, and observed the power by which it is accompanied, more legitimate ideas of it were conceived.