In one sense of the word, philosophy knows, and atheism says, that matter is in perpetual motion. But the motion here meant refers to the state of matter, and that only on the surface of the earth. It is either decomposition, which is continually destroying the form of the bodies of matter, or recomposition, which renews that matter in the same or another form, as the decomposition of animal or vegetable substances enter into the composition of other bodies. But the motion that upholds the solar system is of an entirely different kind, and is not a property of matter. It operates also to an entirely different effect. It operates also to perpetual preservation, and to prevent any change in the state of the system.

Giving then to matter all the properties which philosophy knows it has, or all that atheism ascribes to it, and can prove, and even supposing matter to be eternal, it will not account for the system of the universe, or of the solar system, because it will not account for motion, and it is motion that preserves it. When, therefore, we discover a circumstance of such immense importance, that without it the universe could not exist, and for which neither matter, nor any, nor all, the properties of matter can account, we are by necessity forced into the rational and comfortable belief of the existence of a cause superior to matter, and that cause is God.

The motion of the earth, therefore, is an effect of Divine power, because there is none other equal to it; and the constant operation of the same cause is requisite to perpetuate its progress. How amazing it is that this globe, so large in circumference, should move at all! Plato attributes motion to the power of God, “How is it possible,” he argues, “for so prodigious a mass to be carried round for so long a time, by any natural cause? For which reason,” he says, “I assert God to be the cause, and that it is impossible it should be otherwise.”50 “Every thing that is moved,” adds Aristotle, “must of necessity be moved by some other thing; and that thing must be moved, either by another, or not by another thing. If it be moved by that which is moved by another, we must of necessity come to some Prime Mover that is not moved by another. For it is impossible that what moves, and is moved by another, shall proceed ad infinitum.”51 Since motion then is not a property of matter, but an effect produced by the power of a Divine agent, what a constant display we have of this efficient energy, in moving this earth, and with such a surprising, swiftness! Surely all men should fear and reverence a Being, who possesses and exercises such a power! He who created all things out of nothing, could, if he pleased, extinguish the light, and shake the solid earth into atoms!

When the ponderous wheel of nature first began to move, time, consisting of days, months, years, and ages, and measured by the duration and revolutions of the heavenly bodies, commenced.

The distinction between day and night is a wise and gracious provision for man. In the morning, after the weary limbs have repaired their exhausted vigor by the indulgence of soft repose, we are pleased with the blessing of light; and, after a few fleeting hours engaged in our diversified pursuits of the day, we begin to court the evening shades, pleased again to enjoy that balmy retreat which alone refits us for the fatigues of the ensuing day. When a few fleeting hours are spent, the day is no longer gratifying; but its light becomes burdensome, and we wish for the shadows of the evening to be stretched over us. This sable period is scarcely gone, when we welcome the dawning day, andleave the place of our rest with gladness.

Day and night, and their alternate changes, are adapted to suggest useful thoughts, and calculated to employ our serious meditation.

A force continually impressed by the supreme Being produces and preserves these different and useful motions, which measure out that portion of time assigned us, for the performance of his work, and the securing of our own salvation. We are directed in his word how to employ this important talent lent to us; also warned to guard against a misapplication of it, and told that a day will come when we shall have to give an account of our stewardship. As day is afforded for the management of those employments which could not be done in the night, how unwise would it be to postpone such concerns till the approach of darkness? So the short period of life is given us that we may “work out our own salvation.” We are favored with the light of Divine truth to illuminate our understandings; the operation of the Holy Spirit to influence our wills; and our pressing necessities should impel us to perform what God requires.

The Greeks have two words for time, χρονος and καιρος: the former signifies time in general; and the latter that part of it which is proper for doing a thing—the present season in which any thing to be done may be done fitly and to advantage. Accordingly Solomon says, “To every thing there is a season, and a time to every purpose under heaven.”

What the apostle says to the Christians at Ephesus is equally applicable and interesting to persons in succeeding ages of the world; giving a view of the importance of time, and directing to a right improvement of it. “See that ye walk circumspectly, not as fools, but as wise, redeeming the time, because the days are evil.”

Walking, in the Scripture style, is a word frequently used to denote the whole course of a man’s life and conversation, including all his thoughts, words and actions. Walking circumspectly, ακριβως, signifies correctly, accurately, consistently, or perfectly. In another place the same word is rendered diligently. Herod said to the wise men come from the east, Go to Bethlehem, and search ακριβως, diligently, narrowly, for the young child Jesus. But the word circumspect is from the Latin circumspicio, and signifies to look round about, on all hands, to be every way watchful, wary, and cautious, in order to avoid danger, discern enemies before they come too nigh, and secure a man’s interest by every possible and lawful means.52

The necessity of this duty is suggested in the Greek text, βλεπετε ουν see then or therefore, take care of this as a matter of the highest concern and greatest importance; it is that on which your all depends. He adduces a cogent reason for this—“Not as fools, but as wise.” As if he should say, It is your wisdom to walk circumspectly, and not to walk so would be your folly: to walk circumspectly is the wisdom that God recommends to you, and which is adapted to make you truly wise, both in this world and in that which is to come.

The word redeeming, εξαγοραζομενοι, literally signifies buying time. The term buying is proper in reference to civil contracts, but it is here applied morally. Properly speaking, time cannot be bought: it is a commodity for which all the treasures in the world would not be an equivalent. Its price is above rubies. But the term imports the great value of time, and intimates that we should be willing to suffer any privation or inconveniences, rather than lose it. Redeeming properly implies the laying down a price for re-purchasing or recovering that which was ours, but which has fallen into the possession of another. A captive sometimes is redeemed out of the hand of an enemy. Now, in this sense, to redeem time already past is impossible, for when once gone it is irrecoverable. So that by redeeming time, nothing else can be understood but a diligent and prudent improvement of it, which is the only way in our power to counterbalance the loss we have sustained by our former neglect. The effects of our past negligence should be counteracted by double diligence in future: we should do much work in a little time. This is to redeem that time, concerning which we have allowed worldly business, unprofitable visits, sensual indulgence, carnal recreations, and vain thoughts, to rob us, and, as it were, to take and keep us captive. To redeem time then is to be diligent in future, wisely improving it so as may make amends for our very culpable remissness. Future diligence is, as it were, the price of redemption paid down for what we had mortgaged into the hands of those things which we have suffered to deprive us of it.

The argument used to enforce the practice of this duty is, “because the days are evil.” Time, in itself, properly speaking, is neither good nor evil; but in regard to the moral state of mankind may be so called. The days here primarily intended by the apostle, denominated evil, were those of his own time, in which he himself and his contemporaries lived, and which abounded with trouble and danger, by reason of the opposition made by unbelieving Jews and Gentiles against Christianity. But all our days, as well as those, may be called evil, because of the prevalence of sin, Satanic delusion, and hostility of the ungodly against real religion. Many persons can adopt the language of the patriarch Jacob, “Few and evil have the days of the years of my life been.” Job gives a similar testimony, “Man that is born of a woman, is of few days, and full of evil.”

The whole argument runs thus: seeing that you cannot enjoy true quiet and substantial comfort in this terrestrial abode, and are in danger of being quickly deprived of all opportunity of getting and doing good, fail not to improve the present time to the best advantage, in reference to the future state, that you may secure for yourselves a happy and glorious eternity.

CHAPTER III.
SECOND DAY.

ON THE ATMOSPHERE.

Composition of Atmospheric Air — Atmosphere divided into three regions — Air a fluid — Its compressibility and elasticity — Weight and pressure — Equilibrium — Transparency — Wind — Causes of Wind — Variety of Winds — Velocity of Winds — Destructive Winds — Wind under the control of God — Wind a similitude of the Holy Spirit’s operations.

On the second day God made a space or expansion, surrounding the solid earth to a certain height, called the atmosphere. This word is derived from ἀτμός and σφαῖρα, and signifies a body of vapor in a spherical form. By this name we understand the “entire mass of air which encircles all parts of the terrestrial globe, which moves with it round the sun, which touches it in all parts, ascending to the tops of its mountains, penetrating into its cavities, and incessantly floating on its waters. It is a fluid which we inhale from the first to the last moment of our existence.” The Hebrew word רקיע rakiâ, from רקע rakâ, used by Moses, (and which our translators, by following the firmamentum of the Vulgate, which is a translation of the στερεωμα, of the Septuagint, have improperly rendered firmament,) signifies to spread out as the curtains of a tent or pavilion.53 It corresponds with those beautiful words of Isaiah, “It is he that stretcheth out the heavens as a curtain, and spreadeth them out as a tent to dwell in.” “Thus,” as a learned and pious author justly observes, “the second great production of the Almighty was the element which is next in simplicity, purity, activity, and power, to the light, (or, rather fire,) and no doubt was also used by him as an agent in producing some subsequent effects.”54

It is particularly deserving notice, that, after the creation of caloric, the atmosphere was the next regular production. If heat had not previously existed, could the atmosphere have been formed? The Creator, having first impressed certain principles on matter, impregnating it with repelling forces and systematical attractions, proceeded with his work according to these radical and fixed laws. One of the general laws discovered by Dr. Black, and which is laid down as a chemical axiom, is, that “Whenever a body changes its state, it either combines with caloric, or separates from caloric.” “The most probable opinion concerning the nature of caloric,” says Mr. Dalton, “is that of its being an elastic fluid of great subtlety, whose particles repel one another, but are attracted by all other bodies. Every kind of matter has its peculiar affinity to heat, by which it requires a certain portion of the fluid, in order to be in equilibrium with other bodies at a certain temperature.”55 It is now generally supposed, adds Mr. Parkes, that the air owes its elasticity to the caloric which it contains; and, that if it could be deprived entirely of this, it would lose its elastic form. The expansibility of the air is effected by the operation of caloric: for being rarefied by heat, it occupies a larger space than otherwise it would. It is extremely probable, says Lavoisier, that air is a fluid naturally existing in a state of vapor; or, as we may better express it, that our atmosphere is a compound of all the fluids which are susceptible of the vaporous or permanently elastic state, in the usual temperature, and under the common pressure.56

For the discovery of the composition of atmospheric air, we are indebted to Scheele, an able chemist, born 1742, at Stralsund, in Germany, who was a member of the Academy of Stockholm, and one of the Royal Society of Medicine at Paris, and whose laborious investigations of nature have perpetuated his memory. When the nature of atmospheric air began to be understood, it was imagined that it was a mere mixture of oxygen gas and nitrogen gas; and Mr. Dalton is still of this opinion: but, says Mr. Parkes, we have now abundant reason to believe that it is a mere chemical compound; that is, that the oxygen and nitrogen form atmospheric air by a chemical union. Atmospheric air is a chemical mixture of oxygen and nitrogen rendered aërial by the expansive power of caloric: it likewise contains a portion of carbonic acid gas, which was formerly calculated at one per cent.; but Mr. Dalton has lately demonstrated that it does not amount to more than one part in a thousand.57 Carbonic acid gas is nearly twice as heavy as common air; hence it is evident that it must combine chemically with the atmosphere, or it would be found only near the surface of the earth. If it were merely mixed with atmospheric air, its gravity would prevent it from ascending to any great height: but it is found to exist in the atmosphere at the greatest heights, (though probably not in the same proportion) as well as near the surface of the earth; which is a proof that it is not a mere mixture, but that it is chemically combined with the air. There are about 22 parts of oxygen, and 78 of nitrogen, in every 100 measures of atmospheric air, or 23 of the former and 77 of the latter, if the calculation be made by weight.58

Antony de Marti observes, If a few hundredth parts of oxygen only were wanting in atmospheric air, fire would lose its strength, candles would not diffuse such complete light, and animals would with difficulty separate the necessary quantity of the vivifying oxygen. On the other hand, if the atmosphere were more charged with oxygen than nitrogen, animals indeed would acquire a more free respiration; but, let us consider the activity which fire would acquire by air of superior purity. We know that, on some occasions, the least spark excites the strongest flame in a combustible body, and which increases so much as to consume it in a few moments: candles then would be no sooner lighted than they would be destroyed, without answering any other purpose than that of dazzling us for a few moments: iron would be calcined, instead of acquiring from the fire that softness necessary for transforming it into its various instruments, and which it cannot receive in a more moderate heat. Nothing would be capable of checking the progress of this destructive element, which is nourished by vital air, if this aëriform substance were not abundantly mixed with mephitic air, which serves to restrain it.

Pure atmospheric air is composed of three gaseous substances only, but is perpetually contaminated by a variety of exhalations from the earth. “The atmosphere is a vast laboratory,” says Fourcroy, “in which nature operates immense analyses, solutions, precipitations, and combinations: it is a grand reservoir, in which all the attenuated and volatilized productions of terrestrial bodies are received, mingled, agitated, combined, and separated. Notwithstanding this mixture, of which it seems impossible for us to ascertain the nature, atmospheric air is sensibly the same, with regard to its intimate qualities, wherever we examine it.” Hence, whatever may be the nature of the aërial fluid, when absolutely pure, that which we breathe, and which commonly goes under the name of air, must be considered as an exceedingly heterogeneous mixture, various at various times, and which it is by no means possible to analyze with accuracy. The whole mass of it contains a great deal of water, together with the vast collection of particles raised from all bodies of matter on the surface of the earth by effluvia, exhalations, &c., so that it may be termed a chaos of the particles of all sorts of matter confusedly mingled together. And hence it has been considered as a large chemical vessel, in which the matter of all kinds of bodies is copiously floating; and thus exposed to the continual action of that immense surface, the sun, from whence proceed innumerable operations, sublimations, separations, compositions, digestions, fermentations, putrefications, &c.

Though, in this view, the atmosphere seems to be a kind of sink or common sewer, where all the poisonous effluvia arising from putrid and corrupted matter is deposited; yet it has a wonderful facility of purifying itself, and one way or other, of depositing those vapors contained in it; so that it never becomes noxious, except in particular places, and for a short time; the general mass remaining, upon all occasions, pretty much the same.59 The way in which this purification is effected, is different according to the nature of the vapor with which the air is loaded. Aqueous vapor ascends; and also much of that vapor arising from decayed and putrid animal and vegetable substances, (and which, by some modern philosophers, is called phlogiston, attaching itself to the aqueous vapor,) ascends along with it; and probably descends again with the rain; whence the fertilizing qualities of rain-water above those of any other: while another part is absorbed by vegetables; for the phlogistic vapor is probably the food for plants. But sulphureous, acid, and metalline exhalations, produced principally by volcanos; vapors, arising from houses where lead and other metals are smelted; descend, in consequence of their specific gravity, and suffocate and spread destruction around them, poisoning not only animals, but vegetables also. From all these, the air seems not capable of purifying itself, otherwise than by winds, or by letting them subside by their superior gravity, till they are absorbed either by the earth or water, according as it is their nature to unite with one or other of these elements. Of this kind also seem to be the vapors which are properly called pestilential. The contagion of the plague itself seems to be of a heavy, sluggish nature, incapable of rising in the air, but attaching itself to the walls of houses, bed-clothes, and wearing apparel. Hence, scarcely any constitution of the atmosphere can dispel these noxious effluvia; nor does it seem probable that pestilential distempers ever cease until the contagion has operated so long, and been so frequently communicated from one to another, that, like a ferment much exposed to the air, it becomes vapid, communicates a milder infection, and at last loses its strength altogether.

The atmosphere, or body of air encompassing the earth on all sides, is generally divided into three regions. The lowest region extends from the earth to the place where the air is no longer heated by the rays which the earth reflects: this region is the wannest. The middle region begins where the preceding one ends, and goes to the summit of the highest mountains, or even the highest clouds; this is the space where rain, hail, and snow are engendered: this region is much colder than the preceding one. The third region extends from the middle one to the utmost height of the atmosphere; whose limits have not been ascertained.60 If the air were of an equal density throughout, the height of the atmosphere might be determined: but since the density of the air decreases with the pressure, it will be more rarefied and expanded the higher we go; and by this means the altitude of the atmosphere becomes indefinite, and terminates in pure ether. But though we cannot assign its real height, it is certain, from observations and experiments, that a distance of 45 or 50 miles is the utmost limit where the density is sufficient to refract the rays of light. For the beginning and ending of twilight show, that the height at which the atmosphere begins to refract the sun’s light is about 45 English miles; and therefore that may be reckoned the altitude of the air to the least degree of density.

The air is justly reckoned among the number of fluids, because it has all the properties by which a fluid is distinguished. It requires but little attention to be convinced of this. The air yields to the smallest force impressed on it; its parts are easily moved among themselves; it presses according to its perpendicular height, and its pressure is every where equal. That the air is a fluid consisting of such particles as have no cohesion among themselves, but easily glide over one another, and yield to the smallest impression, appears from the ease and freedom with which animals breathe in it, and move through it without any difficulty or sensible resistance. The ease with which it is penetrated, and driven about in every direction, and the motion of it in pipes and channels, however crooked and intricate, demonstrate its fluidity. It is also known to be a fluid, by the easy conveyance which it affords to sound.

Compressibility and elasticity are evident properties of air. Its elasticity was first ascertained by some experiments of Lord Bacon. The air nearest the earth is in a state of compression, occupying a smaller space than it otherwise would do, were it not compressed by the superincumbent air. It must therefore be in a state something resembling that of a quantity of fine carded wool thrown loosely into a deep pit; the lower strata supporting the weight of the upper strata, and being compressed by them; and so much the more compressed as they are further down, while the upper stratum only is in its unconstrained and most expanded state. If we should suppose this wool thrown in by a hundred weight at a time, it will be divided into strata of equal weights, but of unequal thickness, the lowest being the thinnest, and the superior strata gradually increasing in thickness.61

When the air is in a state of compression, we find that the same force with which we compressed it is necessary to keep it in its bulk; and that if we cease to press it together, it will swell out and regain its natural dimensions, which shows its elasticity. This distinguishes it essentially from such a body as a mass of flour, salt, and such like, which remains in the compressed state to which we reduce it. There is something therefore which opposes the compression of air, different from its simple impenetrability, and produces motion, by repelling the compressing body. As an arrow is gradually accelerated by the bow-string pressing it forward, and at the moment of its discharge is brought to a state of rapid motion; so the ball from a pop-gun or wind-gun is gradually accelerated along the barrel by the pressure of the air during its expansion from its compressed state, and finally quits it with an accumulated velocity. These two motions are indications perfectly similar to the elasticity of the bow and of the air.

Mr. Parkes observes, that atmospheric air in all states, and in all seasons, is permanently elastic. This elasticity arises from caloric being chemically combined with the solid substances of which it is composed. I say solid, because we have abundant evidence that oxygen and nitrogen are both capable of taking a solid form, and actually do, in many instances, exist in a state of solidity. Nitrogen is a component part of all animal substances, and exists in a solid state in all the ammoniacal salts. Oxygen takes the same state when it combines with metals and other combustibles; and in the composition of the nitrous salts they both take the same state of solidity. These facts surely evince that atmospheric air owes its fluidity to caloric.

Dr. Hales, by means of a press, condensed the air 33 times; and, afterwards, by forcing water in an iron globe, into 1,551 times less space than it naturally occupies. The dilation of the air, by virtue of its elastic force, is found to be very surprising. In experiments made by Mr. Boyle, it dilated to 10,000, and even, at last, in 13,679 times its space; and this altogether by its own expansive force, without the help of fire. In fact, it appears that the air we breathe is compressed by its own weight into at least the 13,679^th part of the space it would occupy in vacuo. But if the same air be condensed by art, the space it would take up when most dilated, will be, according to the same author’s experiments, as 550,000 to 1.

It is only by means of the experiments made with pumps,62 and the barometrical tube, by Galileo and Torricelli, that we came to the proof, not only that the atmosphere is endued with weight and pressure, but also of the measure and quantity of that pressure. The rise of water in a pump was formerly attributed to the horror that nature had of a vacuum. This absurd notion was refuted about the middle of the seventeenth century, by the following occurrence. The Duke of Florence, having occasion to raise water to the height of 50 or 60 feet, ordered a common pump to be made for that purpose; but when it was completed, the workmen were astonished to find that it would not work. The matter was referred to Galileo, but he was unable to account for it in any way. All they were able to determine was, that water would not rise in a common pump more than 32 or 35 feet. The fact remained inexplicable till philosophers caught the idea of atmospheric pressure; since when, the suspension of mercury in the barometer, and water in a pump, have been well understood.63

That the air is a heavy body, has been demonstrated by a variety of experiments. The air next the earth is more dense than that at a distance, because, as it is of an elastic or springy nature, it is pressed down by the whole weight of the superincumbent air. Its general force of gravity appears, from its surrounding the earth, and always accompanying it in its orbit round the sun. As the matter of which the air is composed is always variable, so likewise will its weight or gravity be, as barometers of various kinds and structure evince. The weight of the air at the earth’s surface, is found by the quantity of mercury that the atmosphere balances in the barometer; in which, at a mean state, the mercury stands 29½ inches high. And if the tube were a square inch wide, it would at that height contain 29½ cubic inches of mercury, which is just 15 pounds weight; and so much weight of air every square inch of the earth’s surface sustains; and every square foot, as containing 144 inches, must sustain a pressure of 2,160. At this rate, a middle-sized man, whose surface is about 15 square feet, must sustain a weight of 32,400 pounds, or 16 tons; for the air, like other fluids, presses equally upwards, downwards, and sideways, in every direction. But because this enormous weight bears equally on all sides, and is counterbalanced by the spring of air diffused through all parts of the body, it is not in the least felt by us.64

By this enormous pressure we should undoubtedly be crushed in a moment were not all parts of our bodies filled either with air or some other elastic fluid, whose spring is just sufficient to counterbalance the weight of the atmosphere. The human body is a bundle of solids, hard or soft, filled or mixed with fluids, and there are few or no parts of it which are empty. All communicate either by vessels or pores; and the whole surface is a sieve through which the insensible perspiration is performed. The whole extended surface of the lungs is open to the pressure of the atmosphere; every thing therefore is in equilibrio: and if free or speedy access be given to every part, the body will not be damaged by the pressure, however great, any more than a wet sponge would be deranged by plunging it any depth in water. The pressure is instantaneously diffused by means of the incompressible fluids with which the parts are filled: and if any parts are filled with air or other compressible fluids, these are compressed till their elasticity balances the pressure. Besides, all our fluids are acquired slowly, and gradually mixed with that proportion of air which they can dissolve or contain. The whole animal has grown up in this manner from the first vital atom of the embryo. For such reasons the pressure can occasion no change of shape by squeezing together the flexible parts; nor any obstruction by compressing the vessels or pores.

Sometimes the air is so heavy and elastic as to support the mercury in the tube at the height of 31 inches nearly; at other times it is so light and unelastic, as to suffer it to fall as low as 28 inches. The difference between these two altitudes is three inches, that is, about 1-9th of the whole weight of the atmosphere. Our bodies, therefore, are sometimes pressed with a weight one-ninth more than at other times, that is, with about 3,360 pounds more weight at one time than another. This has considerable effect on our feelings, and consequently on our health, but we are apt to ascribe this effect to a wrong cause. When we feel ourselves dull and languid, we think it is owing to the air being too thick and heavy about us. But it is just the reverse: the air is then too light and thin, as is evident from the mercury’s sinking in the barometer, and its not bearing up the clouds: it is seldom dense enough at two miles height to bear them up.65 The weight of the air is proved by its supporting the clouds and vapors which we so frequently see floating in it; in the same manner that the swimming of a piece of wood indicates the weight of the water which supports it.

It may be remarked, says Mr. Parkes, that the Creator has endowed atmospheric air with the property of preserving its own equilibrium at all times and in all places. Its elasticity is such, that, however it may be consumed by respiration or combustion, its place is immediately supplied with a new portion; and though by a mistaken policy the doors and windows of our habitations may be constructed so as to exclude it as much as possible, it will have admission; it forces its way through every crevice, and performs the most important office assigned it, in defiance of all our exertions. If the properties which are given to the different substances in nature, and the laws by which they are governed, be thus examined, we shall find them all tending to promote the welfare and felicity of every species of animated beings.

The transparency of the air is a very beneficial property it possesses. According to Dr. Keill, and other writers on astronomy, it is entirely owing to the atmosphere that the heavens appear bright in the day-time. For, without an atmosphere, that part of the heavens only would shine in which the sun is placed: and if we could exist without air, and should turn our backs toward the sun, the whole heavens would appear as dark as in the night, and the stars would be seen as clear as in the nocturnal sky. In this case we should have no twilight; but a sudden transition from the brightest sunshine to the blackest darkness immediately after sunset; and from the blackest darkness to the brightest sunshine at sun-rising; which would be extremely inconvenient, if not fatal to the sight of men. But, by means of the atmosphere, we enjoy the sun’s light, reflected from the aërial particles, for some time before he rises, and after he sets. For, when the earth by its rotation has prevented us from seeing the sun, the atmosphere, being still higher than we, has the sun’s light imparted to it, which gradually decreases until he has descended 18 degrees below the horizon; and then, all that part of the atmosphere which is above us becomes dark. The atmosphere refracts the sun’s rays so, as to bring him in sight every clear day, before he rises in the horizon; and to keep him in view for some minutes after he is really set below it. For, at some times of the year, we see the sun ten minutes longer above the horizon, than he would be if there were no refractions; and about six minutes every day at a mean rate. We cannot but perceive the wisdom of God displayed in this contrivance, to prevent the sudden transition from light to extreme darkness, and his goodness manifested therein to man.

Besides these, there are many other advantages we derive from the atmosphere. Were it not for the atmospheric air, which is the vehicle of light and sound, our eyes would be useless, and the pleasures which arise from the variegated prospects that now surround us, unknown. Sound would never strike our ears, nor convey the charms of language from one person to another; all the delights of mutual converse would be lost. The sense of smell would never be regaled with odoriferous sweets; nor annoyed with exhalations from putrid and morbid substances. In short, life would become extinct, and a chaos of darkness and emptiness ensue. It has been well remarked, that, if the Deity had intended only to give us existence, and had been indifferent about our happiness or misery, all the necessary purposes of hearing might have been answered without harmony; of smell, without fragrance; of vision without beauty. The consideration of the various uses to which the different substances in nature may be applied, gives so satisfactory an assurance of the goodness of the Almighty, as is calculated to produce in us gratitude and obedience. With this view, an elegant French writer has said on this necessary fluid, “In the use of atmospheric air, man is the only being who gives to it all the modulations of which it is susceptible. With his voice alone, he imitates the hissing, the cries, and the melody of all animals; while he enjoys the gift of speech denied to every other. To the air he also communicates sensibility; he makes it sigh in the pipe, lament in the flute, threaten in the trumpet, and animates to the tone of his passions even the solid brass, the box tree, and the reed. Sometimes he makes it his slave: he forces it to grind, to bruise, and to move for his advantage an endless variety of machines. In a word, he harnesses it to his ear, and obliges it to waft him over the stormy billows of the ocean.”

Wind is air in motion. As the air is a fluid, its natural state is that of rest, which it cannot have but by an universal equilibrium of all its parts. When, therefore, this natural equipoise of the atmosphere is destroyed in any part, the circumjacent air necessarily moves towards that part, to restore it; and this motion of the air is called wind. Hence, where the equilibrium of the air is disturbed, the wind may blow from every point of the compass at the same time: those who live northward of that point have a north wind; those who live southward have a south wind; and so on of the rest: but those who live on the spot, where all those winds meet and rush together, will have turbulent and boisterous weather, such as whirlwinds and hurricanes, accompanied with rain, lightning, and thunder. For sulphureous exhalations from the south, torrents of nitre from the north, and aqueous vapors from every part, are there violently blended together, and seldom fail to produce these phenomena.

The causes of wind augment or diminish the gravity or elasticity of the atmosphere; for two portions of air, which are equal in elasticity or gravity, remain mutually immoveable. We must look for the causes of wind in the variation of heat and cold, the position of the sun, the nature of the soil, the inflammation of meteors, the condensation of the vapors into rain, and other similar circumstances: but the most general causes are heat and cold. Fire, which expands and rarefies the air, diminishes its elasticity, and, consequently, makes it lighter in some places than in others; hence the pressure of the ambient air is greater than that of the rarefied, whence a motion arises; and thus several winds blow towards the part where the air is rarefied by the heat; which currents of air, if strong, are called winds, if gentle, breezes or gales. Thus the air is constantly carried from the polar regions towards the torrid zone, where it is also affected by the diurnal motion of the sun from east to west.

“When we reflect attentively upon the nature of winds in general,” says Dr. O. Gregory, “considering all the causes which disturb the equilibrium of the atmosphere, the great mobility due to its fluidity and its elasticity, the influence of heat and cold upon the latter, the immense quantity of vapor with which it is charged and discharged alternately, the mutual effect of contiguous air and water in motion, the varied attractions of the sun and moon, upon the aërial fluid, and finally the changes produced by the earth’s rotation in the velocity of the atmospherical moleculæ at different parallels of latitude; we shall no longer be astonished at the inconstancy and variety which infringe upon the regularity of some of our winds, nor of the extreme difficulty of reducing the whole to laws wearing the semblance of certainty.”66

There is a great variety of winds. The ancients observed only four, called venti cardinales, because they blow from the four cardinal points. Homer mentions no more than eurus, the east; notus, the south; zephyrus, the west; and boreas, the north wind.67 In imitation of him, others do the same. Afterwards intermediate winds were added, first one, then two, between each of these. Most writers, make only eight winds, and Vitruvius68 informs us that the Athenians built a marble tower in the form of an octagon with eight winds marked, every one on that side which faced it. The moderns make 32 winds, the four cardinal winds 90 degrees distant, and 28 collateral or intermediate, 11 degrees and 15 minutes distant from each other, of which those in the middle between two cardinals, are 45 degrees distant from each cardinal.69 But some make as many points on the compass, and as many winds, as there are degrees on the horizon, namely, 360.

The winds for a considerable space north of the equator, about 30 degrees in the open sea, blow from the north-east, and as far south of the equator, from the south-east. These are called trade-winds, from their facilitating trading voyages. In the Indian ocean, from its particular situation, and that of the lands which surround it, from April or May, to October or November, the wind blows from south-east to north-west; and during the rest of the year from the opposite quarters: these winds are called monsoons. In Jamaica and the Caribbee islands, in the months of July, August, or September, there are usually violent storms of wind, called hurricanes; the wind during the hurricane frequently veering, and blowing in every direction.