MOSPHERE, BAROMETER, BOILING, CLOUDS, DEW, ELECTRICITY, EVAPORATION, FOG, HAILSTONES, HALOS, HOAR-FROST, LIGHTNING, MAGNETISM, RAIN, S.NOW, STORMS, etc.
We confine ourselves here to a historical sketch of the science.
Owing to the complexity of the phenomena, meteorology is the most difficult and involved of the sciences, and seems, indeed, at first sight, almost incapable of being reduced to a science at all. On this account, the only procedure admissible in the first place is long and patient observation, and a faithful recording of facts.
From the nature of the subjects which make up the science, it may be inferred that they occupied men's minds from a remote antiquity. The splendid and ever-varying panorama of the sky, and the changes of temperature through the days and the seasons, with all the other elements constituting the weather, and thus powerfully affecting the necessities and comfort of man, are of a nature well fitted to arrest his attention. From the time spent in the open air in the early ages, and from the imperfect protection afforded against the inclemency of the seasons, those appearances which experience proved to precede a change of weather would be eagerly recorded and handed down. In this way, many most valuable facts were ascertained and passed current from hand to hand; and, perhaps, there is no science of which more of the leading facts and inferences have been from so early a period incorporated into popular language.
Aristotle was the first who collected, in his work On Meteors, the current prognostics of the weather. Some of these were derived from the Egyptians, who had studied the science as a branch of astronomy, while a considerable number were the result of his own observation, and bear the mark of his singularly acute and reflective mind. The next writer who took up the subject was Theophrastus, one of Aristotle's pupils, who clas sified the opinions commonly received regarding the weather under four heads, viz., the prognostics of rain, of wind, of storm, and of fine weather. The subject was discussed purely in its popular and practical bearing's, and no attempt was made to explain phenomena whose occurrence appeared so irregular and capricious. Cicero, Virgil, and a few other writers also wrote on the subject without making any sub stantial accessions to our knowledge; indeed, the treatise of Theophrastus contains nearly all that was known down to comparatively recent times. Partial explanations
were attempted by Aristotle and Lucretius, but as they wanted the elements necessary for such an inquiry, being all but totally ignorant of .every department of physical science, their explanations were necessarily vague, and often ridiculous and absurd.
In this dormant condition meteorology remained for ages, and no progress was made till proper instruments -were invented for making real observations with regard to the temperature, the pressure, the humidity, and the electricity of the air. The discovery of the weight or pressure of the atmosphere made by Torricelli in 1643 was undoubtedly the first step in the progress of meteorology to the rank of a science. This memorable discovery disclosed what was passing in the more elevated regions of the atmosphere, and thus the elevations and depressions of the barometric column largely extended our knowledge of this subtle element. See BAROMETER.
The invention and gradual perfecting of the thermometer (q.v.) in the same century, formed another capital step; as without it nothing could be known beyond vague impressions regarding temperature, the most important of all the elements of climate. This great invention soon bore excellent fruit. Fahrenheit constructed small and portable thermometers, which, being carried by medical men and travelers over every part of the world, furnished observations of the most valuable description—the comparative tempera ture of different countries became known, and the exaggerated accounts of travelers with regard to extreme heat and cold were reduced to their proper meaning. Scarcely less important was the introduction of the hygrometer (q.v.), first systematically used by De Saussure (died 1799), and afterwards improved by Dalton, Daniell, and August. From the period of the invention of these instruments, the number of meteora!ogical observers greatly incrutsed, and a, Loge body of well-authenticated facts of the utmost value was collected. The climates of particular parts of the earth were determined am, the science made great and rapid advances by the investigations undertaken by distin guished philosophers into the laws which regulate the changes of the atmospheric phenomena.