Vapor

“ Apparently, in consequence of the very warm sun, this still and clear day, falling on the earth four fifths covered with snow and ice, there is an almost invisible vapor held in suspension, which is like a thin coat or enamel applied to every object, and especially it gives to the woods of pine and oak intermingled, a softened and more living appearance. They evidently stand in a more genial atmosphere than before. Looking more low I see that shimmering in the air over the earth which betrays the evaporation going on. ”

“ And when, further, this white night encompasses my melancholy eye with flying streams of vapor, with floating, fluttering particles of perfume-dust, then do I sadly see in the vapor human life pictured, with its two great clouds on our rising and setting, with its seemingly light space around us, and its blue opening over our heads.... ”

“ Clinging about them is a semi-transparent vapor that floats and densifies, collecting over their heads. They jump into the air, whirl over harlequin like and descend to push again the boulder.
No sign of vegetation; there must be no air. Can the vapor be their breath? Why does it not float away? In the globe I have tubes to my nose that supply my breath.
The little fairies, are they (I pinch myself) getting into mischief? An adult makes peace by administering sharp pinches. As one moves its mouth to howl, I do too, but cannot make a sound; neither does the child who cries without. ”

“ I suppose the thick air, as well as the transparent, is in both cases saturated with aqueous vapor;—but also in both, observe, vapor that floats everywhere, as if you mixed mud with the sea; and it takes no shape anywhere: you may have it with calm, or with wind, it makes no difference to it. You have a nasty haze with a bitter east wind, or a nasty haze with not a leaf stirring, and you may have the clear blue vapor with a fresh rainy breeze, or the clear blue vapor as still as the sky above. ”

“ Mother Ambroisine was not pleased.”
“By heat,” continued Uncle Paul, “water becomes invisible, intangible, as subtle as air. That is what is called vapor.”
“You told us that the moisture in the air, the cause of fogs and clouds, is also vapor.” This from Claire.
“Yes, that is vapor, but vapor formed only by the heat of the sun. Now, you must know that the stronger the heat, the more abundant is the vapor. If you put a pot full of water on the fire, the burning heat of the grate sets free incomparably more vapor than the temperature of a hot summer sun could. ”

“ When in every vessel of heated water mankind had always seen a vapor arise, who could have supposed that in this simple fact, nature had furnished an agent, which by skilfully managing, he could multiply his natural strength a thousand fold, and move from place to place with the swiftness of a bird? By the alternate production and condensation of this vapor, which he is able to do by the very common agents of fire and water, he is able to extract the ponderous minerals from the bowels of the earth, having made it previously drain off the water which put them out of his reach. ”

“ Vapor is always going up. Most of it goes up from the ocean, the lakes and rivers. Three fourths of our big world is covered with water, you know. The sun warms the top layer of water and turns it into vapor. Every leaf and blade of grass on the land has water in it. The sun steals this water, too. Sometimes it takes so much and gives so little back again that the grass turns brown, and the leaves wilt. Every animal and plant drinks water and breathes it out again from the lungs, or gives it to the air through little holes in the skin called pores. ”

“ The quantity of vapor which the air can contain varies according to temperature, warm air being able to hold more than cold air.
As the air is cooled, its power of retaining vapor diminishes. When it becomes colder than the temperature at which it is able to keep its supply of vapor dissolved, the excess of vapor is condensed and becomes visible. ”

“ Water, flowing over a bed of this mineral, liberates the gas in the form of an almost invisible vapor. It is swept forward in a cloud by the wind, some of it is carried along above the course of the underground stream, and as soon as it reaches an opening in the earth, like a fissure crack in the rock or ground, the gas rises and whoever breathes it dies or is rendered unconscious for a time, according to the strength of the vapor. ”

“ Aqueous vapor in the atmosphere, whether its presence is rendered sensible to the sight or not, implies the action of heat. Other things being equal, the greater the heat the greater the quantity of watery vapor in the air. In the summer, for instance—though many imagine the contrary—there is much more of such vapor in the air than there is in winter, the greater heat of the air enabling it to keep a greater quantity of the vapor in the invisible form. ”

“ Do you observe that vast sheet of white vapor that is rising from yonder valley? It is rising in consequence of the warmer air that is produced by the rising of the sun. Do you not feel that the shining of the sun upon you makes you warmer? ”

“ The Sun said “Yes,” and took ever so many other drops, too, so that Aqua might not be lonesome on the way. He did not know this, however, for they all had been changed into fine mist or vapor. Do you know what vapor is? If you breathe into the air, when it is cold enough, you will see it coming out of your mouth like steam, and you may also see very hot steam coming from the nose of a kettle of boiling water. When it is quite near to the earth, where we can see it, we call it “fog.” ”

“ And how nobly it raises our conceit of the mighty, misty monster, to behold him solemnly sailing through a calm tropical sea; his vast, mild head overhung by a canopy of vapor, engendered by his incommunicable contemplations, and that vapor—as you will sometimes see it—glorified by a rainbow, as if Heaven itself had put its seal upon his thoughts. For, d’ye see, rainbows do not visit the clear air; they only irradiate vapor. And so, through all the thick mists of the dim doubts in my mind, divine intuitions now and then shoot, enkindling my fog with a heavenly ray. And for this I thank God; ”

“ They could also see it throwing up from its air-holes to a great height a cloud of vapor, or of water, for, strange as it may appear, naturalists and whalers are not agreed on this subject. Is it air or is it water which is thus driven out? It is generally admitted to be vapor, which, condensing suddenly by contact with the cold air, falls again as rain. ”

“ The whole ashy material fell now continually around us, and in vast quantities. The range of vapor to the southward had arisen prodigiously in the horizon, and began to assume more distinctness of form. ”

“ Vapor is perpetually rising from the ocean, and is condensed by cold in the hills and high lands, as is easily recognized by the mists and rains, which are frequent in such regions; whence it descends through their pores and crevices, till it is deflected, collected and conducted out to the sea, by some stratum or channel which is water-tight, thus keeping up a perpetual and compound circulation. ”

“ The moment the vapor is condensed into rain, the latent heat, which was taken up with the vapor, is liberated, and the consequence is, the formation of a furnace in the sky, as it were, overhanging the raging storm, and travelling along with it. ”

“ When vapor obstructs light it is owing to impurities contained in it, to currents of varying densities, or wave motions, or to a mechanical mixture of condensed water and air, whereby multitudes of tiny globular water surfaces are produced. ”

“ I was watching the heated vapor rising from our tea-kettle the other night, and was much diverted to notice that it made a whistling sort of sound as it emerged from the nozzle of the pot. It ran from B sharp to high C, and was loud enough to be heard on the other side of the room. It has occurred to me that there may be in this some hidden principle that will some day [177] enable man to make this vapor do his work for him, especially along musical lines. ”

“ That body, as many of you know, is aqueous vapor, the amount of which does not exceed one per cent of the whole atmosphere. Minute, however, as its quantity is, the life of our planet depends upon this vapor. ”

“ Exposing next the globe to the temperature of boiling water, the liquid will evaporate, and we shall have our vessel filled with ordinary steam. If, now, that cubic foot of space is really packed close with the material which we call water—if there is no break in the continuity of the aqueous mass, we should expect that the vapor would fill the space to the exclusion of everything else, or at least would fill it with a certain degree of energy which must he overcome before any other vapor could be forced in. ”

“ This is what takes place in the formation of steam in a vessel containing water in free communication with the atmosphere. At first, a vapor is seen to rise that seems to come from the surface of the liquid, getting more and more dense as the water becomes hotter. ”

“ We inquire whether this quantity of motive power is necessarily limited, whether it varies with the substance employed to realize it, whether the vapor of water offers in this respect more or less advantage than the vapor of alcohol, of mercury, a permanent gas, or any other substance. We will try to answer these questions, availing ourselves of ideas already established. ”

“ If you observe smoke, steam, or any vapor, you will find that the farther you are from it, the more difficult it is to see through it. The fog which hides the distant mountains, or even the sun, does not obscure those objects immediately about you; the thin vapor which you see at a distance covering the meadow, disappears on approaching it. ”

“ I. The first difference is, that heat is an expansive motion, by which the body strives to dilate itself, and to [154] occupy a greater space than before. This difference is principally seen in flame, where the smoke or thick vapor is clearly dilated and bursts into flame.
It is also shown in all boiling liquids, which swell, rise, and boil up to the sight, and the process of expansion is urged forward till they are converted into a much more extended and dilated body than the liquid itself, such as steam, smoke, or air. ”

“ Of course the sun when it shines turns some of the water into vapor that rises again to the sky. Sometimes on a cool morning you can see the mist or vapor too heavy to rise out of sight and too light to fall as rain. Wherever there is water, some of it is rising into the air, especially when the sun shines and it is warm and the wind blows. The sea is so big that great quantities of vapor are rising from it all the time and being blown over the land to be cooled, to gather into rain and to fall again where it will refresh the earth and make the plants grow. ”

“ Vapor is brought to that condition by intense heat, that it forms a sort of film, or atmosphere, between the hand and the hot iron, and for a time that atmosphere is not too hot to be perfectly bearable. ”

“ Into the path pursued by the carbonic acid in our first experiment, a flask, which I have frequently employed to charge air with vapor, was introduced. Through a volatile liquid, partially filling the flask, air was forced into the tunnel t t' which was thus divided into spaces of air saturated with the vapor, and other spaces in the ordinary condition. The action of such a medium upon the sound-waves issuing from the bell is very energetic, instantly reducing the violently-agitated flame to stillness and steadiness. ”

“ When air passes over, or rests on, oceans, or lakes, or rivers, etc., it becomes laden with vapor, whose influence is very potent, as its power of absorbing and retaining heat is thousands of times greater than that of air. ”

“ Water in the condensed state is heavier than the air and will seek the lowest places, but when vaporized, as in the process of evaporation, it is lighter than air and floats upward. In the vapor state it is transparent like steam. If you study a steam jet you will notice that for a short distance after it issues from the boiler it is transparent, but soon it condenses into cloud. ”

“ However long we boil a fluid, in an open vessel, we cannot make it in the smallest degree hotter than the boiling point.93 When arrived at this point, the vapor absorbs the heat, and carries it off as fast as it is generated. When water is received into the atmosphere, if the air be warm, it becomes so far changed by its union with the matter of heat as to be perfectly invisible. ”

“ It is derived from the vapor of water present in the air. This word vapor is often used to describe some kind of visible mist or fog. But these visible forms of moisture are not properly vapor in the sense in which the term is used in science. The aqueous vapor of the air is always invisible, even when the air is saturated with it, and only when it passes back into the state of water do you actually see anything.
When the invisible vapor dissolved in the air becomes visible, as in mists, clouds, dew, or rain, it is said to be condensed, and this process of liquefaction is called condensation. ”

“ For instance, a cold pitcher in the summer robs the vapor in the air of its heat, and causes it to be deposited on its own surface,—of course the water comes from the atmosphere, not through the wall of the pitcher; if we breathe on a knife blade, it condenses, in the same manner, the moisture of the breath, and becomes covered with a film of-water ”

“ It is possible also that the vapor, which has risen from the earth, being repelled by the stars, may produce thunder, when it is pent up in a cloud; nature restraining the sound whilst the vapor is struggling to escape ”

“ Within the boiler this steam is transparent and invisible; but to keep it in this invisible state a heat would be required as great as that within the boiler. When the vapor mingles with the cold air above the hot funnel, it ceases to be vapor. Every bit of steam shrinks, when chilled, to a much more minute particle of water. The liquid particles thus produced form a kind of water dust of exceeding fineness, which floats in the air, and is called a cloud.
[Pg 204] Watch the cloud banner from the funnel of a running locomotive: you see it growing gradually less dense. ”