The law is always the same; out of nine times which the E. wind blows, it only rains once; whilst it rains once in three times during the SW. wind. The influence of seasons is also recognised. Whilst it frequently rains in winter during E. or N. winds, these same winds are almost always dry in summer. This fact accords very well with what we have said on the relative humidity of the different winds, for with E. winds the air is very dry in summer, but very moist in winter. Rains brought by NE. winds are even very different from those brought by the SW. When the NE. wind suddenly begins to blow, the temperature falls; large drops of rain fall in abundance for several moments; the sky then again becomes serene. In SW. winds, the rain is fine, and lasts a long time. So the rains are in general due to a cooling, and to the precipitation of the vapours brought by the SW. wind. In high latitudes, on the contrary, the NE. wind suddenly cools masses of air, which can then no longer contain vapours in the elastic state. As these winds succeed each other with a certain regularity, there must follow a very regular succession of changes of weather; on this we will now make a few observations.

305. "When the weather has been fair for a long time, and a SW. wind begins to blow in the higher regions of the atmosphere, cirri make their appearance, and soon cover the sky. Beneath them is formed a stratum of cumulus, which allows a light rain to escape. The wind turns to the W., the clouds become thicker, the rain falls more abundantly, and the air becomes colder. With the N. or NW. wind the rain continues, although the thermometer falls. In winter, the rain passes into the state of snow. the wind does not entirely cease with the N. wind, it is not, however, continuous; the blue of the sky is seen in the intervals which separate the clouds. Showers alternate with sunshine, especially with the NE. wind; but if the wind passes to the E. or the S., the sky is then covered with small rounded cumuli, or else it becomes perfectly serene. These phenomena succeed each other in an almost uniform manner, over

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large surfaces. Mountain-chains alone have the power of slightly modifying the succession of phenomena. If they extend from N. to S., they arrest the SW. wind, and it will rain more on their W. than on their E. side. Thus the SW. is not the rainy wind in the S. of Germany, but the NW.; because the SW. winds lose the water with which they are charged when they arrive on the other side of the Alps. The same thing happens in the Scandinavian peninsula. On the W. side of Norway, rain falls for entire days during SW. winds, the summits of the Scandinavian Alps are covered with hoar-frost; and on the other side of the chain only a few drops disturb the serenity of the sky of Sweden. The sea-winds lose the moisture with which they were charged in traversing the large table-land that separates the two countries; so that it rains more frequently in Sweden with E. than with W. winds. The proof that this is not connected with the vapours which rise from the Baltic is, that a similar relation is found in Finland. Wherever the region of rainy E. winds comes into contact with that of the rainy W. winds, it rains indifferently with all winds; this is remarked at St Petersburg. We are still in want of a sufficient number of observations in order to follow out these laws into their details.

my own observations on this subject. Whatever may be the accuracy of the higher rates of velocity I cannot say, for no ordinary means of judging of them exists, except by seeing the shadows of clouds passing along the ground; but the accuracy of the smaller velocities may very easily be judged of. It is said that wind moving 2 miles an hour is "just perceptible;" and at 3 and 4 miles it constitutes what are called "gentle winds." Let us test these. Suppose the air to be perfectly calm when one is walking at the rate of 3 miles an hour, is there felt any thing like a "gentle wind" upon the face? I think not. Were it therefore moving at the rate of 3 miles an hour, it would be as little felt. Before wind is felt at all, one may safely conclude that the air is moving at a greater velocity than 3 or 4 miles an hour, whatever indication anemometers may give for the human skin is a much more delicate indicator of the gentle motions of the air than any instrument. On this view of the subject Sir Richard Phillips makes these pertinent remarks: "If wind blows 100 miles an hour-that is, 528,000 feet-then, as air is 833 times rarer than water, this moving at the rate of 660 feet, or 1 furlong per hour, would be equal to it, which is absurd. There must be some mistake. A West India hurricane has blown heavy cannon out of a battery, and water at 5 miles an hour would scarcely bend a twig. Balloons have travelled 60 miles an hour, when the anemometer showed but 8 miles."* When I have observed the shadows of clouds flying over the land in a windy day in spring or summer, I was convinced that the wind may move hundreds of miles per hour; and in this country the highest wind has a small velocity compared to that at times in the tropics. It is recorded that such was the noise occasioned by the hurricane that took place at Pondicherry on the 29th October 1768, that when the signal guns were fired to warn the ships off the coast, their reports were not heard by even the inhabitants within the fort.t

312. The subject of Storms, in their origin and direction, after a long period of neglect, has of late again attracted the

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attention of philosophers. So long ago as 1801, Colonel Capper, of the East India Company's service, in his work on winds and monsoons, gave it as his opinion that hurricanes would be found to be great whirlwinds. This idea was adopted and confirmed by Mr W. C. Redfield of New York, in a memoir on the prevailing storms of the Atlantic coast of North America, which appeared in Silliman's Journal in 1831. Colonel Reid, of the Royal Engineers, has since then treated the subject in a philosophical manner in a recent dissertation. His attention was first directed to it in 1831. His military service at Barbadoes, immediately after the desolating hurricane of that year, which in the short space of seven hours destroyed 1477 houses in that island alone, naturally led him to the consideration of the phenomena of hurricanes. After much consideration and investigation, he was impressed with the regularity with which storms appear to pass toward the north pole, always revolving in the same direction, that is, opposite to the hands of a watch, or from the E. round by the N. W. S. to E. From this circumstance he was anxious to ascertain whether the revolution would not be in an opposite direction in the southern hemisphere; and this point was well illustrated by the disastrous storm, in the Indian Sea, of 1809, in which nine sail of Indiamen foundered. found the general phenomena of these storms to be as a great whirlwind, represented by the revolution of a circle, whose centre is made to progress along a curve or part of a curve, which is, in most cases, of a form approaching the parabolic, the rotatory circle expanding as it advances from the point at which the storm began to be felt, its rotatory motion in the northern hemisphere being in a contrary direction to that in which the hands of a watch go round, while in the southern hemisphere the rotation is in the same direction as the hands; the diameter of the circle, over which the whirl of the storm is spread, often extending from 1000 to 1800 miles. In the centre of the whirl is a comparative calm, while in its circumference the storm rages, and the wind blows from every conceivable quarter. ‡

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313. There are concomitant circumstances attendant on storms worth relating. Major Sabine found the magnetic intensity least at St Helena, where there are no violent storms. The line of least intensity passes through the Pacific Ocean; the lines of greatest magnetic intensity, on the contrary, seemed to correspond with the localities of hurricanes and typhoons; for the meridian of the American magnetic pole is found to pass not far from the Caribbean Sea, and that of the Asiatic pole through the China Sea. He found He found two instances of water-spouts, one in the northern, the other in the southern hemisphere, in which the revolutions moved in opposite directions, and both in contrary directions to great storms. He explains the variable high winds of our latitudes, by storms expanding in size, and diminishing in force, as they approach the poles, their meridians at the same time nearing each other, and occasioning a huddling together of the gales.

314. Sir Snow Harris of Plymouth has discovered that there is a connexion betwixt the force of the wind, and the hororary oscillations of the barometer. Thus the mean force of the wind for the whole year, at 9 A.M. was 0.855, and at 9 P.M. 0.605; but at 3 P.M. it was 1.107 of Lind's anemometer.*

315. M. Schübler has shown that winds have a characteristic electric power. The precipitations during the wind from the N. half of the circle of azimuth, have a ratio of positive to negative electricity, which is a maximum, and in the other half it is a minimum; the negative precipitations when the wind is S. being more than double the positive ones. The mean intensity of electricity, independent of its sign, is greatest in N. winds.t

316. There being an atmospherical wave as well as a tidal one, and as any elevation of the atmosphere cannot fail to produce a change in parts immediately below the point of disturbance, there seems no reason to doubt that an analogy exists betwixt the tides and the winds, and also with rain. If high tides at London Bridge happen at 12 or 1 noon, rain falls more

frequently than at other periods, if the wind is in the E. So it seems probable that, when the changes of the wind can be calculated more perfectly, we shall have more correct tide tables. It thus appears that the nearer the high tide is to noon the greater is the probability of rain, because the breeze from the sea is then strongest.

317. The approach of high wind may be anticipated from these general prognostics :-when cattle appear frisky, and toss their heads and jump-when sheep leap and play, boxing each other-when pigs squeal, and carry straw in their mouths-when the cat scratches a tree or a post-when geese attempt to fly, or distend and flap their wings when pigeons clap their wings smartly behind their backs in flying-when crows mount in the air and perform somersets, making at the time a garrulous noise-when swallows fly on one side of trees, because the flies take the leeward side for safety against the wind-when magpies collect in small companies, and set up a chattering noise.

318. These are general indications of a storm:-When the missel thrush (Turdus viscivorus) sings loud and long, on which account this bird has received the name of the storm-cock-when sea-gulls come in flocks on land, and make a noise about the coast, and when the porpoise (Phocana communis) comes near the shore in large numbers.

319. Every one is aware of the uncertainty of foretelling the state of the weather, but every one who has attempted to foretell it, and has not succeeded, is not aware of the nature of the many particulars which render his success doubtful. These particulars are thus well enumerated and arranged by Mr Mudie:-" Though one of the most interesting subjects connected with the economy of our globe, and its use and comfort to man, this is one of the most difficult subjects that can engage his inquiry. One reason of this is, the vast number of elements that have to be studied and taken into account; the different laws which each of these obey; the indeterminable nature of many of them; and the modifying influences which

they have upon each other in their joint working. Thus, the daily and seasonal motions of the earth, and the action of the sun and moon; the reciprocating influences of the hemispheres-those of sea and land, of plain, or valley and mountain, and of surfaces covered with vegetation of different characters-are all causes of the weather; but in most instances, particularly in such variable climates as present themselves about the middle latitudes of the quadrant, and near the shores of the sea-more especially in small countries surrounded by it-these causes are so blended with each other, that it is impossible so to analyse the result as to assign to each of them its due state in bringing about the particular weather of any day, any week, or any period, longer or shorter."

320. BOTANY.-The student of agriculture should become acquainted with systematic botany and botanical physiology. The former will enable him to recognise any plant he may meet with in the fields and pastures, and the latter will make him acquainted with the internal structure and functions of the plants he is about to cultivate in agriculture.

321. Systematic botany may be acquired by two methods, the artificial or Liunean, which was the only method known for many years, and the natural method, which was later discovered and established by Jussieu. It has become the practice of some botanists to decry, of late years, the Linnæan method of acquiring a knowledge of the particular parts of plants, and to extol the excellences of the natural method. For my part, I should be sorry to see the Linnæan method entirely abandoned, because I am persuaded that a beginner will much sooner be able to recognise any plant he finds by it than by the natural method: and after all, the Linnæan is a natural method of studying the construction of plants, inasmuch as the component parts of a flower, upon which the system is founded, as much belongs to the making up of a plant, as its aspect, form, and habits; and besides, the Linnæan method does not neglect the form of the leaf, the character of the stem,

or the structure of the root, any more than the natural or Jussieu method. No doubt, when plants are grouped in relation to their general structure, form, habits, and uses, they become objects of much greater interest and beauty, than when examined with a view to be placed in any artificial arrangement; and on this account the natural method possesses a charm which the longest and most intimate study of the Linnæan method could never present; still it is only when the botanical student has far advanced into the study of plants, and has become acquainted with their properties and uses, that he can appreciate the beauties and advantages of the natural method. Such being the case, it appears to me the most rational method of acquiring a knowledge of botany is to become acquainted with individual plants as well as possible; and which may be done bythe Linnæan method, and then to contemplate them in groups according to the natural method of Jussieu.

322. Botanical physiology, which makes us acquainted with the internal structure and functions of the several parts of plants, and the circumstances by which the exercise of these functions is observed to be modified, can only be successfully acquired after the study of systematic botany, and, I should say, after it had been studied in the manner recommended above. This is a science which has been but recently developed, and its development has been mainly brought about by the persevering researches of the chemist, and the use of the microscope. We have only to look into the works of Professor Johnston and of M. Raspail, to be convinced of the vast amount of labour which has been bestowed by chemists in analysing in the laboratory, and observing with the microscope the minutest details of the structure of plants, most of which had eluded human research. In the absence of a sufficient knowledge of their structure, the functions of plants were misunderstood, and in consequence the wildest conjectures were advanced to account for the phenomena they exhibited; but now the functions of plants are daily becoming more and more understood; we now know that plants only receive their food from the soil in a state of solution,