The cumulo-stratus is that fleecy cloud which is some times observed to settle on the summit of a cumulus, while the latter is increasing from beneath. It usually prevails in the completely overcast sky, and apparently without any regard to temperature, as it is found to precede either a fall of snow or a thunder-storm. Be fore the latter, it is frequently to be seen in different points of the horizon, rapidly swelling to a great mag- nitudc. Its indication is doubtful, and must be deter mined by the prevalence of the other modifications that accompany it.
The nimbus generally appears in the form of a dense inverted cone of cloud, the upper part of which spreads in one continuous sheet of cirrus to a great distance from where the shower is falling. When the total eva poration of the cloud that remains after the shower takes place, it is reckoned a prognostic of fair weather. When the nimbus appears by itself, it generally moves with the wind, but when formed in the midst of cumuli, it sometimes moves in a contrary direction. This is often the case with thunder showers.
We do not think it necessary to pursue this subject any farther. The above sketch will be sufficient to en able such of our readers as are engaged in meteorolo gical pursuits to record the appearance of the clouds, according to Mr. Howard's classification; and those who wish for farther information upon the subject may con sult, besides the works already referred to, Forster's Treatise on Atmospheric Phenomena.
\Ve come now to enumerate some of the prognostics of the second class, viz. those that are derived from phenomena, which are observed on the surface of the earth, or at least in the lower regions of the atmosphere. These phenomena are of t ari ou s kinds, such as the ex pansion and contraction of flowers—the motions and cries of certain animals—painful sensations in thc hu man body, &c. and though many of them are no doubt fanciful, yet others appear well entitled to the attention of meteorologists. Some of them indeed, especially such as are drawn from the economy of plants, admit of a philosophical and satisfactory explanation, as every body must know who is in any degree acquainted with phisiological botany. Thus it is stated, by Sir J. E. Smith, that " the Convolvulus arvensis, Anagallis arven sis, Calendula pluvialis, and many others, are well known to shut up their flowers against the approach of rain ; whence the ?nagallie, (or Pimpernel,) has been called the pour man's weather glass." It as also bt'en ascer tained, that the Parliera hyyrometra, a Peruvian plant, uniformly contracts its leaves at the approach of lain), weather, which it predicts with the greatest certainty. See BOTANY. In these, and many other instances that might be given, the irritability of the plant is obviously excited by some change in the state of the atmosphere, which change is either the immediate cause, or conco mitart of rain.
It is probably owing to some atmospherical influence of a similar kind on the animal system, that the pecu liar cries or motions of some beasts, and certain sensa tions in the human body, are found to indicate changes in the weather, though it may be difficult, or in the present state of science, even impossible to explain that influence. Thus, it has been long observed, and very generally believed, that rain may be expected when swallows are observed frequently dipping their wings in the water over which they are flying—when the crow or the peacock cries louder and more frequently than usual—when water-fowl are particularly clamorous and active—when dogs appear unusually dull and sleepy— when the croaking of frogs is loud and general—or when worms are seen in great numbers on the surface of the earth. It is commonly supposed too, that the
noise of sea gulls about the coast, and the approach of the porpus and dolphin to the shore, are certain indi cations of a storm at sea, and wind is generally expect ed at land when pigs are observed to run about with evident signs of uneasiness. It is equally well known, that persons subject to rheumatism and other similar diseases, or who have accidentally suffered injury in any of their limbs, generally feel more acute pain in the part affected before a change of weather, than at any other time ; and we know instances in which these pains are most severe, before or during a sudden de pression of the barometer. This coincidence points to something like an explanation of the phenomenon ; but we avoid at present proposing any thing on the subject. Neither do we think it necessary to enter at greater length into a detail of facts with which our readers in general must he familiar, and of which they will find an extensive at,,I amusing collection in Fors ter's treatise on Atmosr;i:erie phenomena, formerly re ferred to. We would only remark, in conclusion, that these popular prognostics, fanciful as many of them un questionably are, and connected as they have too fre quently been with the most absurd and ridiculous su perstitions, ought nevertheless to find a place in every meteorological register ; and to overlook them, is to re ject the means which nature herself seems to have pointed out, for investigating her operations in a very interesting class of phenomena. We are aware, indeed, that the modern philosopher, who fancies that he can never depart far enough from the beaten track of vul gar opinions, may be disposed to smile at the idea of calling in the observations of the illiterate, to aid him in his scientific pursuits, or of attaching any importance to the pretended discoveries, as he may think them, of a class of men, who are always ready to trace cause and effect between any two events, however unconnected they may in reality be, provided they happen about the same time, or nearly at the same place. He ought to remember, however, that what has been stated as matter of fact by thousands in every age and country, as is the case with many of the prognostics alluded to above, is not to be rejected because it may appear to him fanciful or absurd--that instead of endeavouring to set it aside with a sneer, his own philosophy calls upon him to investigate the reality of the alleged phe nomena in the first instance--and that, if it be as it is represented, he is bound by the principles of the same philosophy to admit it as a fact, whether he can assign the cause of it or not. He might be reminded too, of what is perhaps a very humiliating consideration, but not on that account the less true, that the shepherd, who is totally ignorant of the constitution and properties of the atmosphere, and altogether unacquainted with the laws which regulate the distribution of its heat and moisture, can, by his own experience and obseivation, predict the changes of the weather at a greater distance and with more certainty than the philosopher is able to do, with the aid of all the discoveries of modern sci ence. This indeed, is not the only, nor as some may be disposed to think, the most interesting object of me teorological pursuits ; but while it is in itself of general ly acknowledged importance, it serves at the same time to demonstrate, that some at least of the popular max ims that prevail on the subject, are founded on fact, and are in reality the lessons which are taught in the school of nature herself.