WEATHER is the condition of the atmosphere at any time in respect of heat, moist ure, wind. rain, cloud, and electricity; and a change of weather implies a change in one or more of these elements. From the direct bearing weather-changes have on human interests, they have from the earliest times been closely watched, so that the causes by which they are brought about may be discovered, and their approach predicted with some confidence. The craving in the public mind for this knowledge is strongly attested by the weather prognostics of every language, which, with much that is shrewd and of considerable value, embrace more that is vague, and not a little positively absurd.
It is not necessary here to refer to Moore, Zadkiel, and other almanac-makers of that class, except as proving by their mere existence a wide-spread ignorance of even the most palpable elements of physical law. Prognosticators of higher pretensions repeat. edly appear before the public, and it is curious to note how their predictions are laid. hold of by the newspapers, and scattered broadcast over the country. Among this class was Mathieu de la Drome, whose predictions of storms and rains made so much noise. that the emperor Napoleon requested the celebrated Leverrier to examine the grounds on which his predictions were founded. The exposure was complete. One of his principal predictions was based entirely on a high average of the rain-fall at a particular season. On examining the rain-fall of the particular years from which the average had been taken, it was found that the excess was entirely due to an unprecedentedly heavy rain which occurred in one of the years at that season. One of the most remarkable predictions of recent times was made by an Irish nobleman in reference to Sept. 1865, which turned out to be in accordance with the prediction—dry, warm, and fine, beyond precedent for that month. The celebrity of this prediction has, however, been greatly reduced by other predictions made since, which the event did not verify.
The changes of the moon were long, and hi many minds still arc, regarded as sup plying the elements of prediction. In order to test the real value of the moon's changes on the weather, the Greenwich observations of 50 years were carefully examined, and it was found that the number of instances in which the weather was in accordance with the prognostication was one instance less than those in which the weather was different. When brought to the test of accurate examination and figures, the theory of the moon's changes on the coming weather is by this, as well as by similar investigations of old.
records of the weather, proved' to be a delusion ; but since most people have a bias toward forgetting the unsuccessful and remembering the successful prognostications, the theory may continue to be accepted, until a sounder knowledge of the natural laws are more generally diffused.
For some years Mr. Thomas du Boulay predicted the general character of the weather of each slimmer from the weather-cenditions which prevailed during the week of the spring equinox preceding, supposing that the general character of the weather of the next six months is already settled, and that it only requires the necessary skill to read its features, since these will remain generally constant till autumn. For a few years he speculated in grain on the faith of the predictions, which turned out pretty correct. Latterly, however, his predictions were not verified.
The truth is, that no prediction of the weather can be made, in the British islands at least, for more than about two days beforehand. Any attempt at a longer prediction is illusory. We would hero refer to the article STORMS, as showing the possibility and mode of making real predictions of the weather. Almost all the weather-changes of Europe begin from westward, and pass over Great Britain, following a generally easterly course. Unsettled or bad weather is accompanied with a low barometer; elsewhere, the barometer is higher. Suppose that from weather-telegrams received, it is seen that everywhere in Europe barometers are high, no storm is imminent and generally none is likely to happen for about two days at least. But if, on the following morning, barometers begin to fall a little in the west of Ireland, and an easterly wind begins to blow over Great Britain and Norway, and a s.e. wind over France; then, seeing the winds blow toward the lowest barometer, or rather a little toward the right of it, the presumption is that a storm greater or less severity is coming up, the center of which is likely to pass over England. This ought., therefore, to be closely watched; and if the winds keep in nearly the same direction, or veering slowly toward the s. and w., increase in force, and barometers in the west of Ireland fall rapidly, a great storm is portended, of the approach of which warning should be at once issued. But if, on the contrary, the winds do not increase in force, and the barometer fall only slightly, or cease to fall, the storm has either passed considerably to the n. of the British islands, or its approach will be delayed for 'some. time; and hence no immediate warning may be necessary.