What the Rosetta stone is to the history of the Pharaohs, these Greenwich tables have been to the weather-hieroglyphics. They have afforded something like a key to the language in which the secrets are written; and it remains for industrious observation and scientific zeal to complete the modern victory over ancient ignorance. Already the results of the Greenwich studies of the weather have given us a number of curious morsels of knowledge. The wholesale destruction of human life induced by a fall in the temperature of London has just been noticed. Besides the manifestation of that fact, we are shown, that instead of a warm summer being followed by a cold winter, the tendency of the law of the weather is to group warm seasons together, and cold seasons together. Mr. Glaisher has made out, that the character of the weather seems to follow certain curves, so to speak, each extending over periods of fifteen years. During the first half of each of these periods, the seasons become warmer and warmer, till they reach their warmest point, and then they sink again, becoming colder and colder, till they reach the lowest point, whence they rise again. His tables range over the last seventy-nine years--from 1771 to 1849. Periods shown to be the coldest, were years memorable for high-priced food, increased mortality, popular discontent, and political changes. In his diagrams, the warm years are tinted brown, and the cold years gray, and as the sheets are turned over and the dates scanned, the fact suggest itself that a gray period saw Lord George Gordon's riots; a gray period was marked by the Reform Bill excitement; and a gray period saw the Corn Laws repealed. A few more morsels culled from the experience of these weather-seers, and we have done. Those seasons have been best which have enjoyed an average temperature--not too hot nor too cold. The indications are that the climate of England is becoming warmer, and, consequently, healthier; a fact to be partly accounted for by the improved drainage and the removal of an excess of timber from the land. The intensity of cholera was found greatest in those places where the air was stagnant; and, therefore, any means for causing its motion, as lighting fires and improving ventilation, are thus proved to be of the utmost consequence. Some day near the 20th of January--the lucky guess, in 1838, of Murphy's Weather Almanac--will, upon the average of years, be found to be the coldest of the whole year. In the middle of May there are generally some days of cold, so severe as to be unexplainable. Humboldt mentions this fact in his Cosmos; and various authors have tried to account for it--at present in vain. The favorite notion, perhaps, is that which attributes this period of cold to the loosening of the icebergs of the north. Another weather eccentricity is the usual advent of some warm days at the beginning of November.