from its own mass, and the variations to which the pressure of the air is naturally subject, render it necessary that every pump shall be considerably shorter than 34 feet.

In philosophical experiments, it is very convenient to make use of a heavier fluid than water to show the pressure of the air: for a vertical column of 34 feet is rather a cumbrous apparatus. It is therefore customary to substitute quicksilver, which is so much heavier, that a column of 30 inches is all that the pressure of the air can raise, weighing as much as a column of water having the same diameter 34 feet long. This is something so manageable, that we may dispense with the lever and bucket altogether, and lift a column simply by filling a tube with it, more than 30 inches long, and closed at one end, and then inverting it in a cup of quicksilver. A glasstube thus filled, and inverted in a cup of mercury, is named a Barometer, and in one form or other is found in almost every house. Not that in every house there are philosophers, but there are always people who are interested in the weather, and the barometer is a weather glass. It has been found, by experiment, though we are unable to explain the phenomenon, that much damp in the air over any place lightens it; and, consequently, shortens the mercurial column, which measures its weight. As it is thus when the air is very damp that bad weather usually comes, by finding that the mercury is falling, we may often be able to prognosticate its arrival, or to guess with some degree of accuracy as to the quality of the coming weather.

We are, in the present state of philosophy, unable to explain how it is that a tendency to rain, or snow, or excessive wind in the atmosphere, should diminish the pressure of the air, and cause the mercury to fall; but such having been found to obtain pretty generally, the instrument is of considerable value as a weather-glass. The following statements may, perhaps, be regarded as an index to its motions :

1. In summer, a rise indicates the approach of fair weather. In winter, it generally indicates frost; but, at all seasons in this region, the same effect is liable to be produced by an

east or north-east wind.

2. In summer, a fall generally precedes rain, or a south or south-west wind, or a hurricane or thunder. In winter, it usually precedes rain or thaw.

3. An unsettled state of the mercury usually obtains in unsettled weather.

4. The good or bad weather, which the barometer announces, will generally be of long or short duration, according as it is a longer or shorter time in coming, after the observed rise or fall of the barometer.

5. If the barometer rise from nine in the morning till three or four in the afternoon, fine weather may be more confidently ex. pected; and if it fall from that hour of the

afternoon until nine or ten at night, rain is Indicated with greater certainty than when the reverse takes place; because these movements are in opposition to its natural horary oscillations.

We have thought it necessary to say so much on the pressure of the atmosphere, because, though it be natural philosophy, rather than chemistry, and not particularly agricultural in its bearings, yet almost the first step in science is to become acquainted with these facts, of which, if we are ignorant, every natural phenomenon must remain a mystery. We shall now make some remarks upon the temperature of the air, in which the agriculturist, more than any other man, is concerned.

The heat of the air is chiefly, if not altogether, produced by the rays of the sun. It is, indeed, comparatively difficult to raise the temperature of gaseous bodies, particularly when they are very thin. Being in the ultimate state to which heat can reduce them, it is not wasted on them. For though the present opinions of philosophers imply an excessive waste of heat, there is every reason to believe, that, were the true theory discovered, we should find here the same economy as in other matters with which we are better acquainted. But though we cannot esteem the present hypothesis as to heat as sound, as this is not a place for criticism, we shall use the common ideas. The atmosphere, at least in its more dense strata, near the earth's surface, is capable of having its heat raised from actual contact with the earth's surface, to which, perhaps,

radiant heat contributes a little.

Of this there can be no doubt, that the temperature of a place mainly depends on the quantity of sunbeams alighting upon it. This, for different places, must be very different, because the earth's form is not a flat surface facing the sun, but a globe, of which of course, except the part which is nearest the sun, all the other parts lie back from him. It is not distance, however, that makes the difference, but the obliquity of the base of all the cylinders of rays, except those which fall towards the centre or equator of the globe. To render this more plain, let the accompanying circle represent the world, and the straight lines

scale, the face of a hill is warmer than its back, and southern than northern slopes, supposing the whole to be equally in the sunshine. But this is not the only cause of the temperature of a place. Although it is of great advantage for a district to lie fairly to the sun, and low, that (other things being equal) it may have a dense atmosphere over it, easily heated; yet the condition of the surface exerts a powerful influence, and the character of the neighbouring countries or seas.

Thus, if there be much marshy ground, wet land, or any condition of surface calculated to charge the air with damp, the air will be comparatively cold; because, as we have found, in explaining the barometer, much damp in the air lightens it, and light air, as has been stated, is with difficulty heated. Water itself, too, whether in a liquid state or as vapour, is extremely difficult to be heated; and therefore both circumstances combine to make wet lands cold lands. It is very interesting to observe how beautifully the laws of nature operate to keep down such a state of things, and how kindly they combine with the husbandman, rendering his labours to ameliorate the soil a means of ameliorating the climate also. That there shall not be much air cold and very damp at the same time, is provided for by the law, that the power of air to contain damp diminishes as its temperature falls. And that the climate shall be improved by improving the condition of the soil, and the improvement of the soil, once effected, be for ever kept up, is provided for by the same law. For when the surface has been drained, and the water run off to the sea, or gathered together in deep pools, which present but a small surface compared with a field, and from which, of course, a comparatively small evaporation can take place, then the average temperature of the place rises, and its average power of taking up damp increases; so that though the same quantity of rain should fall in the course of the year as before improvement, still the air will take it all up, and keep the soil in good condition. Instead, then, of ascribing the foulness of our pastures -the lateness and poorness of our crops-the stiffness of our land-the miriness about the farm-the wetness of the land-the coughs and consumptions of the family, to the quantity of rain that falls, let the ground be effectually drained, and the heart of the air will be warmed towards the farmer. Rain will be sent in due quantity to refresh the fields, but it will no longer be left in the furrows. The warm air will suck it up as soon as could be wished. Without draining off the superfluous water, it may be safely stated, that an elevation in the temperature of the air would be productive of the most fatal consequences. But the fevers which originate from the lungs being exposed to cold, damp air, in a sterile country, are mild to a degree (the very idea of death is often carefully banished by the

disease), compared with those fierce and fatal ones generated by warm damp air in regions of vegetable luxuriance. The intermittent fevers or agues of our own fenny districts are light matters; but those which visit other climates of greater heat, rival the plague itself, to which, in fact, they are most nearly related. Thus, in the year 1754 or 1755, a particular wind, named the Harmattan, which rushes from the south-east upon the coast of Guinea, loaded with vegetable exhalations with which it becomes charged in sweeping over the immense uninhabitable swamps and oozy mangrove-thickets of the sultry regions of Benin, produced such devastation in the Negro towns, that the living were not sufficient to bury the dead; and the gates of Cape Coast Castle were shut up for want of sentinels to do duty.*

But not only does the nature of the surface, in reference to water (and had we been particular, we might have said in reference to colour, porosity, &c.), affect the temperature of the air; the character of the neighbour. hood extends often a great many miles. Thus, who does not admit the coldness and injurious character of our east winds in spring? And yet they seem to be generated so far away as the snows of the north of Europe, but because we have a more temperate climate and lighter air, at an earlier part of the season they blow our way, having here a less pressure to keep them off. Such accidents as these we cannot help. Happily they send our vessels rapidly from the Baltic, laden with flax, and are disposed also to forward wool to us in great quantities, to make warm clothing against their influence.

Having touched on the subject of winds, perhaps it may not be wrong to state a few things with regard to their cause and effects. The circumstances in which we see these best illustrated, are in the cases of the land and sea breezes of climates warmer than our own. When the sun-beams shine down, we shall say upon an island, the island and the air above it are heated faster than the sea; for water, as has been already stated, is very slow of heating. Heated air is thinner or lighter than cold air: for it is a property of heat to expand all bodies, or rather we should say, that we call air, hot or cold, according as it naturally is more or less expanded. But if the air over the island be lighter than that over the sea, it will be squeezed up into higher regions of the atmosphere, by the cool air from the sea pressing in upon it, which itself in a little becomes heated over the land, and so is squeezed up in its turn by the air at its back, and thus, during the sunny hours of the morning and forenoon, a breeze blows in upon the land from the sea on all sides. During the absence of the sun, the current is reversed, because the sea, though longer in heating than the

'Good's "Study of Medicine," vol. ii. p. 65.

land, is also longer in cooling, and the air over the land is more heavy during the night than that over the sea. Now, this explanation as to the cause of the land and sea breezes (the former of which, by the way, is very well pronounced in our own climate during summer), supplies all that we know regarding the cause of winds, viz. a difference of temperature in different portions of air, and the destruction of equilibrium or stillness resulting from it. Electricity is no doubt powerfully concerned; but we are too ignorant of its action in the atmosphere, to be able to avail ourselves of it in explaining the phenomena of winds. The effects of winds upon the earth's surface are very beneficial, and having selected the land and sea breeze to illustrate their cause, we may still make use of it to illustrate their effects. During the night, as has been stated, a breeze blows from the land, when men and animals generally are asleep, and when the vital functions of vegetables also, in consequence of the cold, are relaxed, when, in a word, the whole organic creation is less irritable than during the day. Now, this land breeze, borne over the marshy grounds of the interior, is charged with unhealthy exhalations, and those organic particles, which, of whatever nature they may be, are the cause of fever. We see, then, the wise provision in causing it to blow, and carry off to the sea these noxious malaria, when nature is asleep and animals housed. Nay, there is a moral on its breath. For, though it blows over putrescent swamps, it is also wafted over mountains and valleys, covered, in these climes, with fragrant flowers; and though it is charged with infectious particles, like apothecaries' drugs, they are disguised with delicious odours, tempting the senses. But the man who indulges to excess suffers, like other voluptuaries. Let us now see how matters change in the morning. The sun rises and awakes all nature; and, after a devotional stillness for a time, when the bright hours of the day come, the breeze sets in from the sea, cooled, and purified by the salt water, from its putrescent particles, and worthy of being called the Doctor, by which name the English sailors designate the breeze. In this case, then, we see the effects of winds in purifying the air over any given place. On the great scale, winds are equally efficient in purifying the whole atmosphere, by bearing it successively over the ocean, the absorbing power of which probably destroys its putrescent particles. This carrying to the ocean is not conducted with much regularity in our own latitudes, where, in consequence of the low temperature of the air, it is not so subject to be corrupted by decomposing plants and animals, and where the cold of winter probably destroys the life or morbid activity of these mysterious atoms. But, in warm climates, there is a strong

breeze constantly blowing over the Atlantic, Pacific, and Indian Ocean; and were this the place for it, it might be shown, that, in a certain time, the whole atmosphere must perform the tour of these currents, and be swept clean by the ripple on the surface of the sea beneath. Besides purifying the air, winds are of very great use in carrying about heat from place to place, so as to equalize the temperature of the globe, as far as its globular form will permit. Aqueous vapour is borne about by them in the same way; and it is highly probable that these great oceanic currents which have been mentioned, as purifying the atmosphere, are the means also of charging it with a supply of moisture to refresh the dry land. They are also valuable in accelerating the spontaneous evaporation of water; for, though the cause of the phenomenon may not be very well understood, the fact is certain, that water is carried into the air much more rapidly when a strong wind is blowing, than when the air is calm.

If our globe were of the same quality of surface every where, the gradation of heat and climate, from the tropics to the poles, would be quite regular. But the irregular distribution of land and water gives rise to a very different state of things. The former, as has been stated, is much more easily heated than the latter; and as there is a much greater quantity of land in the northern than in the southern hemisphere, it is much warmer. For the same reason, countries having land lying south or sunward of them, enjoy a far more temperate climate than those which have sea; because the land diffuses northward a part of its superior heat derived from a more vertical sun. For this reason, the east-coast countries of Europe are very temperate, being warmed by heat conducted from Africa, as from an oven, and from its own southern provinces. For the same reason, the western coast of America is comparatively cold; for an immense tract of ocean lies to the south and west.

But it is now time to remark, that the heat of the air not only depends on latitude, or its distance from the equator; the altitude of a place produces the very same effect. This arises from the fact which has been already stated, that thin air is much more difficultly heated than dense air, and we know that air becomes thin as we ascend. From experiment, it is found that for every 300 feet that a place lies above the level of the sea, we must allow a degree less of mean heat, which, though it seems a small quantity, tells wonderfully upon the ripening of a crop. The consequence of this diminution of heat in the higher regions is the existence of a certain altitude over every place, where water can only exist in the solid form, where, in short, there is perpetual frost, and where, of course, all vegetation must cease. This line, named the Snow Line, or

LANGUAGE."

THAT the English language, whilst it is daily extending its empire abroad, is daily encountering contempt and insult at home, is a truth which it is equally grievous and imperative to admit. Our magazines and light publications the whole of our periodical literature, in fact, seems devoted to the cause of introducing amongst us, bad French and Italian, to the exclusion of all the forcible phrases which our own language can afford. One of our annuals has inserted, this year, a whole tale in French; and none of the many reviews which have noticed it, have done so in terms of reprobation, with the single exception of the Gentleman's Magazine, the last strong-hold of good old English feeling, and pure old English idiom. What adds to the absurdity of this is, that the professed author of this tale, though a Frenchman by birth, has long resided in England, is perfectly acquainted with its language, and has even composed in it essays and other light productions; so that he could, if required, have furnished the tale in our mother tongue. Others of this popular class of periodicals are ornamented with prints, bearing French and Italian titles, and illustrated by tales, written in that despicable gibberish, unfortunately but too prevalent, composed of English sentences, interlarded with French phrases and French idiom.

There is no doubt that this miserable affectation, this vulgar parade of superficial learning, is the surest sign of utter ignorance that can be shown. Those who are really and thoroughly acquainted with these languages are aware, that in many, nay, in most particulars, the English language completely surpasses them, that in capabilities it is unrivalled, and that, though all those capabilities have not yet been sufficiently exerted or adequately called into action, they may be safely awakened from their slumber upon occasion, by magicians of no very extraordinary powers. If the gentlemen who so liberally intersperse their composition with foreign terms, had that knowledge of their native language which they ought to possess, we should not see English books disgraced by the intrusion of the wretched French phrase coup de soleil for the brief and forcible sunstroke, leger de main for sleight of hand, eclaircissement for clearing up, pas de trois for dance of three, vinaigre de quatre voleurs for four thieves' vinegar, &c.; all which it is reasonably expected that every reader shall pronounce aright, according to the French fashion, as if it were a sacred duty incumbent upon every Englishman, to study a language

* From the Gentleman's Magazine for March..

his own.

What renders this infatuation still more provoking, is, that it has reached (what I hope may be) its topmast height, at a time when England boasts of authors, second to none in the annals of literature, save a few of the great names of antiquity; and when France is absolutely inferior in this respect, not only to England, but to Germany, Italy, and Spain. If the relative situations of the two nations in regard to literature were exactly the reverse, the phenomenon might be satisfactorily accounted for. It is no very unusual occurrence, for servile imitations of good foreign models to be carried so far, as to cause it to be forgotten, that it should be aimed at to transfer their characteristic excel. lencies to our own idiom, instead of servilely repeating them in theirs. But our present conduct is to stoop from our own proud preeminence, to the level of an acknowledged in. ferior; we, the imitated, act as if we were the imitators; and by so doing we merit to be sneered at, as we are by our foreign com petitors.

It is evident to all those who have devoted any portion of attention to the subject, that the English language would, if proper care were devoted to its advancement, stand an excellent chance of becoming more universally diffused, read, and spoken, than any other now is, or ever has been. In Europe, the study of it seems to be gradually spreading. In Germany, Russia, and Scandinavia it is esteemed an essential, in France a highly useful, branch of education; in Africa it is gradually superseding the Dutch, and becoming the medium of valuable information. In Australasia it is not only widely spoken, as the only European language known on that vast continent, but written and printed in an almost incredible number of newspapers, magazines, and reviews. In Asia so great is the desire manifested to learn it, that it was thought by Bishop Heber, that, if proper facilities were afforded, it would, in fifty years, supersede Hindoostanee, and become the court and camp language of India. In America, millions already speak, write, and read it, as their mother tongue; and it is rapidly obliterating the savage languages and French from Canada, and the rest of the north of the Northern Continent. Never before did language look forward to so bright a prospect as this, and nothing could retard its swift march but our own incredible folly. By stupidly and (I may almost say) wickedly introducing French into our books, we are, as it were, compelling all those who wish to study English literature, to acquire the French language also.

That tongue has already acquired an almost inexplicable preponderance in Europe, which certainly possesses at least half a dozen supe rior in every particular. It is admitted as the