ADVANTAGE OF WARM CLOTHING.

There are men, called chemists, who know a great deal concerning the nature of different kinds of substances, and who, in consequence of this knowledge, are able to bring about very surprising changes and effects. These men have places, termed laboratories, or labor shops, in which they work, and which are divided into distinct chambers, besides being furnished with all sorts of instruments and vessels. Sometimes liquids are put into these chambers and vessels, and there turned into solids. Sometimes both liquids and solids are converted into invisible air. Sometimes beautiful crystals, white and blue, green and red, are brought out of transparent and colorless fluids. Sometimes a few grains of dusty looking powder are made to vanish into smoke with an explosion that shakes the ground for yards; and sometimes waste rubbish is transformed into delicious scents, resembling those which are produced from the violet and the rose. Even dull, black charcoal has been changed into the sparkling and precious diamond. It would require a very large book merely to number the wonderful feats these men of science are able to perform. Chemists, indeed, in the present day can do much more by their knowledge and skill, than magicians pretended they could accomplish in the olden time.

Chemists make use of many very powerful agents in their laboratories, to aid them in carrying out their objects and plans. Among these agents there are two that stand before all the rest both in strength and in general usefulness. These prime assistants of the chemists are fire and water. The water is employed to dissolve substances whose little particles it is desired to bring closely together. When two different liquids thus formed are mixed, all the particles in the two come together and act upon one another. Fire is used to soften substances, and loosen the hold of their little particles upon each other, so that they may afterwards be readily mixed together. Water dissolves bodies; that is, makes them liquid by uniting them with itself. Fire melts bodies; that is, makes them liquid without the aid of water.

Now there is one object which the chemists often have in view, when they put different kinds of substances together, in a dissolved or liquid state, in the chambers and vessels of their laboratories; that is, to get something out of those substances, which was before hidden away in them, in order that they may turn that something to practical use. Thus the chemist mixes together saltpetre, sulphur, and charcoal in the right proportions to make gunpowder. Then having rammed a charge of the gunpowder down into the tube of a gun, with a bullet on the top of a charge, he applies a spark to the gunpowder, and makes it change into smoke and vapor. Something which was hidden away in the gunpowder ceases to be concealed when it is changed into smoke and vapor, and becomes active enough to be able to drive the bullet out of the muzzle of the gun with a force that carries it through the air for a mile, and perhaps then buries it deep in the ground, or in a plank of wood. This is an instance of the way in which chemists produce motion, by changing the state and condition of material substance.

I had occasion the other day to watch a still more interesting example of this strange result of the chemist’s skill. In a chemist’s laboratory, prepared for a particular service, I saw several small chambers of metal, half copper and half zinc, into which were poured blue vitriol and water, and an acid, a partition wall of pipe-clay standing between. The dilute acid and the zinc were slowly turning into white vitriol, which remained dissolved away in the water; but out of this new-made white vitriol there flowed a power, which was conveyed along a wire, and which made a needle, hung up on a pivot before me, twitch from side to side, almost as if it had been a living thing. I was told that this power set free in the solution, in consequence of the changes brought about there, would run along the wire to the distance of a hundred, or even of a thousand miles, and would there make another needle work and twitch in the same way. In short, I was looking at the electric telegraph at work, and learning that the agent which made the signal afar was simply a power that had been hidden away in the different substances the chemist put together in the metal chambers, and that was set free and enabled to operate in the production of independent motion, so soon as those substances acted upon one another, and altered the form and state in which each was existing.

Now, my good friend, your living body, and my own, are laboratories, in which changes of precisely the same kind are constantly brought about; your living body, and my own, are made of an enormous quantity of separate chambers and vessels, very small, it is true, but nevertheless such as can be seen quite distinctly when they are looked for with the microscope. In these small chambers and vessels different kinds of substances are thrown together, exactly as the zinc, and acid, and blue vitriol are in the laboratory-chambers of the electric telegraph. The chambers and vessels of the living laboratory lie between meshes of the supply pipes of the body, and it is indeed their minute cavities which are drenched by the circulating streams of the dissolved food (see “Value of Good Food”), and in which that dissolved food gets to be transformed into flesh and fat, gristle and bone, tendons and skin, fibres and nerves. The blood, which is pumped forth with such vigor from the heart, creeps along slowly through the smallest and furthest branches of the supply-pipes, in order that plenty of time may be given for all these changes to be worked out in the chambers of the frame. But the fibres and skin, the flesh and the nerves, when they have been built up, are also changed into waste substance by admixture with yet other ingredients which the blood brings to the little chambers. In the cavities of the living laboratory, as in those of the electric telegraph, these changes of substance lead to the setting free of agents before concealed, which agents then operate in the production of movements and of other living effects. When I now raise my arm up above my head, I am able to do so because some of the flesh of which my arm is composed, is changed into another kind of substance, the moving power being set free during the change. When I feel this hard stone which I take up in my hand, I am able to do so because some of the substance of which my body is made, is changed into another kind of material at the instant that I feel. This, then, is how strength comes out of food. The food is changed into flesh, and the flesh is converted into two distinct parts, waste substance and moving and living power. The power was originally concealed in the food, placed there by the provident hand of the Divine Author of Nature, in order that it might be forthcoming for this useful service when it was required. In simple words, material substance is destroyed in order that power may be extracted from it. Material substance, in living bodies, is turned into power. This is the mechanism by which God works in these, the most wonderful of the productions of his hands.

It will hardly be necessary, after all that has been already said elsewhere, to point out that the prime assistant of the chemist, water, acts in the living laboratory exactly as it does in the artificial ones. It loosens, dissolves, and mingles together the various substances which are to act upon one another. It is in the dissolved food, and the liquid blood, which flow into all the chambers and vessels of the living body, and which build up in them the fibres of living structure, and then transform and destroy those fibres, in order that the power there stored away may be obtained.

But it is still more remarkable that the other prime assistant of the chemist, fire, should also be employed in the living frame, in loosening its particles, and in quickening the operation of the various changes of substance upon which the production of power depends. It has been shown that in the body of a full-grown man there is as much heat produced in a single day, as would serve to make eighty pints of cold water boil, and it has also been stated that this heat is produced in the body exactly in the same way heat is produced in the steam engine; that is, by the burning of fuel. The heat is set free by the change of condition in material substance, precisely as power is procured. When the water employed in a steam engine is made to boil, the heat that causes the boiling issues from the coal, because that substance ceases to be coal, and turns into smoke and vapor. Just so the fuel substance of the body ceases to be fuel substance, starch, sugar, and fat—and turns into vapor, which is steamed away, leaving the heat which was concealed in the substance to warm the frame.

The furnace which is kept burning in the living laboratory, to quicken all the operations which are being carried forward in it, and to furnish its strength, is a slow and gentle one. It never burns quickly enough to cause light and flame, as common fires do. The body is never even raised to the heat of boiling water, which is far less than that of burning coal. It is only made of blood-heat; that is, sixty-eight degrees of the heat-scale warmer than freezing water,—in its warmest parts. Boiling water is one hundred and eighty degrees of the same heat-scale warmer than freezing water. The furnace of the living body sometimes burns a little more quickly than it ought, then the body gets warmed into fever. Occasionally it burns considerably less quickly than it ought, then the body is chilled, and its living actions and powers are slothful and languid. Upon the whole, however, its heat is steadily kept up at pretty much what it ought to be, that is, at one hundred degrees of the scale, which gives thirty-two degrees for frost.

Now this is how the furnace of the living body is kept smouldering on in its gentle and even way. Little blasts of air are constantly puffed in upon the burning fuel. That out-and-in play of your chest as you breathe,—that is the puffing of air blasts into certain chambers of your living laboratory, to keep up its smouldering fires. The more quickly and deeply you breathe, the warmer your body becomes; and the more slowly and softly you breathe, the colder that body remains. The same action which blows a fresh wind through the living frame to clear away its impure vapors, also serves to fan its hidden flames, and keep its fuel burning. When the breathing is stopped the fires of the body go out, just as those in a common furnace do, when their air-blasts are arrested, and the body becomes dead cold.

You will remember that when the fresh air is drawn into your lungs as you breathe, it enters a large quantity of little cavities or chambers, which have, all of them, a fine net-work of the supply-pipes stretched out upon their walls; and that as the blood rushes on in its course through these supply-pipes, it sucks air into itself from the air-cavities, and carries it, in its own streams, to all parts of the living structure. Air goes with the blood to that strong force-pump, the heart, and is then pumped out with the blood to every crevice and fibre of the body. Every part of the body therefore receives, by means of the supply-pipes and in the blood, heat-fanning air, as well as supporting food.

When air reaches the living flesh and nerves, by thus flowing to them in the blood-streams of the supply pipes, it sets up those changes of substance in their structures which lead to the production of movement, and feeling, and other kinds of living power. When it reaches the dissolved fuel, contained in the blood and in the various little furnace-chambers of the laboratory, it sets up those changes in the fuel which lead to the production of warmth. The fuel is slowly burned in the blood and in the chambers of the frame, and there gives out warmth, as a fire does whilst it is burning in a grate. This warmth consequently heats the blood, and the warm blood carries its heat wherever it goes. The entire body thus becomes as warm as the blood, or nearly so.

Now, where do you think all the heat originally comes from, that is procured from burning fuel? The heat is stored away in the fuel, as one of the ingredients of its composition, until it is burned. But where was the heat obtained from, which is stored up in the fuel? Of course, when the fuel was made, that heat-store had to be supplied to it, as well as its other ingredients. First let us see when and how the fuel was made, and perhaps we shall then be able more perfectly to understand this matter of its warming qualities and power.

In the case of coal, it is not a very difficult task to trace the stored-up heat to its source. But what a surprising truth it is, which becomes apparent when the task has been performed. The heat is, so to speak, bottled-up sunshine! Coal is dug up from deep mines hollowed out in the earth. But at one time it was wood, growing on the outer surface of the globe, and covered with foliage which was spread out into the genial air. Traces of the leaves and stems from which it has been made, are still discovered in its substance. Long centuries ago, the vast forests containing these trees, were overthrown by some tremendous earthquake, and swept away by strong floods of water, and so the tree-stems were at last deposited in hollow basins, and were there buried up by millions and millions of tons of heavy rock and soil. There, where they were buried, they have remained, turning more and more black and dense through the process of slow decay, until they have been dug up piece-meal to feed the furnaces and fires of the existing generation of men.

Now, you know very well that trees only grow in warm weather, and in sunshine. In winter time their branches stick out stiff and bare, and do not increase in the slightest degree. But in summer time they clothe themselves with beautiful masses of foliage, and suck in from both the air and the soil large quantities of vapor, of liquid food, and of sunshine. All these they combine together into fresh layers of timber. All these therefore were buried in the ground as timber, when those old forests were overthrown which form the coal-beds. Timber cannot be made in cold weather, because heat is one of its necessary ingredients. But as all the warmth of the weather comes from the sun, it is the sun’s warmth which is stored away in the coal, and which is set free and made useful when the coal is burned.

The grand source of all warmth on the earth is that brilliant light which God has placed in the sky to rule over the day. In a summer’s day you sit down in the bright sunshine, and bask in its warmth. In winter time, when the sky is covered with clouds, and ice and snow lie thick over the ground, you place yourself indoors near the glowing fire; but strange to say, it is still the sun’s genial warmth that you experience. If the fire be of coal, it is warmth which was borrowed from the sun centuries ago. Reflect for an instant upon this marvellous arrangement entered upon, for your comfort, ages before you were yourself called into being! When those coal-making forests spread their broad masses of foliage out in the sunshine, there were no human creatures existing upon the earth; and, indeed, not even the flocks and herds, which are so essential to man’s welfare, had been framed. Neither cattle nor sheep could have found pasture on the plains which yielded them support. The great duty of those forests must have been to store up genial warmth for then uncreated generations of beings, who in due season were to appear, and to avail themselves of the provision thus made.

But suppose that you had neither fresh nor stored-up sunshine to fall back upon, and had to depend entirely for your warmth upon that furnace which is carried about in your living laboratory, and kept alight by the puffing of your breath. Still that internal heat comes originally out of the sunshine. Just before the time when man was placed upon the earth, the beautiful family of plants was created, which fills the gardens with roses, and which yields the apple, the pear, the cherry, the plum, the apricot, the peach, the almond, the strawberry, and the raspberry. Just at the very time was planted on the globe, the vegetable tribe which furnishes the different kinds of nourishing grain, and which provides pasture for grazing animals. The fruits, the grasses, and the grain were all commissioned to extract power and warmth from the sunshine, and to store it up in such a form that the influences could conveniently be introduced into the interior of the living body. Living animals which are warmed by the fuel contained in their food, procure their heat from sunshine that was stored up, as it were, but yesterday. When animals live upon flesh, and get their strength out of the lean fibre, and their warmth out of the fat of this food, still it must be remembered that the flesh has been fed on the grass of the field just before. The main office of the plant in creation is thus to store up in a fixed and convenient form supplies of active energies which can be turned to account by animated frames. The plant effects this end by preparing the food upon which animals live;—that food which, besides keeping the body in repair, serves also to furnish it with warmth, and to give it strength and power. How admirable and beneficent is this plan, whereby the genial influence of life-quickening sunshine is economized and preserved for the service of one-half of creation, by the instrumentality of the other half!

In the far distant regions of the north, there are places on the earth to which no daylight or sunshine comes for four long months at a time. During this gloomy period the ground goes on, from hour to hour, scattering more and more of its heat, until it is almost as cold as the chill space in which the great world is poised, and has indeed more than 100 degrees of frost. The land and the water alike get covered up by one broad and thick sheet of never-melting ice and snow. There is not a leaf, or a grass blade, or a vegetable stalk any where in the wide white desolation. But there are animals and human beings, who are born and die, who maintain a prolonged existence in it. Let us just look in upon one of the households in this drear frost land, and see what the odd community is like.

In the midst of a broad snow waste, through which the sharp wind is howling with a fearful sound, there is a small mound nearly covered by the snow-drift. We perceive this mound by faint starlight, the only gleam that comes down from the sky. A few feet away from the mound we discover a small hole blocked up by a lump of snow. We move the lump aside, and stretching ourselves out at full length on the ground, we squeeze into the hole head foremost, and crawl along a narrow passage, burrowed out in the firm snow for about a dozen feet. We then find ourselves in a vault ten feet wide and fifteen feet long, and so low that we can scarcely sit upright within it. This is the inside of the mound. It is the interior of a hut, or dwelling-place, of these people of the drear frost land. The walls of the hut are built of large stones piled together, with a padding of frozen moss covered over them, and with thick ice and snow covered over the moss.

There are twelve living individuals, men, women, and children, huddled together in this close vault. They have no fire to keep them warm. Indeed, there is neither coal nor wood which they could use to light a fire, within many hundred miles. There is in one corner of the hut a broad shoulder-blade of a large quadruped laid flat, and in the hollow of this blade there is some crushed seal’s blubber, and some soft moss, with long cotton-like rootlets. The end of the moss is burning with a small, dull, smoky flame. This is the only artificial source of light and warmth within the hut.

But these people are all of them almost entirely naked; and they are dripping with perspiration, they are so warm. Outside of the hut, in the dim starlight, the air is actually a hundred degrees colder than freezing water. Yet inside, in the nearly as dim lamp light, there are almost as many degrees of warmth. The air is there as hot as the hottest summer day in England! All this heat is produced in the slow furnaces of those twelve individuals’ own living bodies. They have lost the sunshine for months, and everything around them is much colder than ice. They are living upon the flesh and blubber of seals, and sea-horses and white bears, animals which they killed before the sun went away, the meat being kept for them through their long winter by the preserving power of the frost. The sunshine of past away summers has given its heat to plants; the seals and sea-horses have fed on those plants, or upon smaller animals which have done so, and have transferred the heat into their own blubber; and now the benighted savages are getting the heat out of the blubber to keep their own flesh and blood warm and unfrozen. In that close hut, where no sunshine can come for months, the savage inmates have nevertheless abundant stores of the warmth of sunshine, which have been laid up and preserved for their service. Such care Providence takes even of these, the rude and barbarous children, whose lot he has cast in the desolate outskirts of the world!

The rude people who dwell in the cold frost-land of the north, remain warm through their long, severe winter, without the aid of artificial fires, because they economize the warmth which is produced in the slow furnaces of their bodies, and prevent it from being scattered away as quickly as it is generated. If they were to set themselves down in the open air, instead of in their close huts, the warmth produced in their bodies would be thrown off from the outer surfaces of these as fast as it was set free from the fuel. In the close huts, on the other hand, this warmth first heats the air contained within the stone walls, and is then a very long time in getting any further, and so prevents more heat from being rapidly scattered from the internal furnace.

These human inhabitants of the northern ice land have a companion in their desolate haunts, who does not build himself a hut after their fashion, but who has instead a somewhat similar protection against the severe cold of the long northern winter, provided by nature. This creature goes upon four legs, sometimes swimming in the water, and sometimes stalking along upon the ice. He is very powerful and fierce, is armed with sharp claws two inches long, and has teeth which can bite through thick and hard metal. He is able to tear iron and tin to pieces as if they were merely paper or pasteboard, and he feeds upon seals, birds, foxes and deer, which he manages to catch by his cunning and address. This savage creature is often killed by the rude natives, who hunt him with dogs and spears, but in the absence of man he is the fell tyrant of the domain. He prowls about on the snow-wastes, destroying every living body which comes within his reach; and he remains exposed to the severest cold of the long dark winter, lying upon the ice and snow, without having his life-blood frozen by its chill power. The reason of his safety is that he wears a nature-provided great coat of very warm fur. His skin is every where covered by long shaggy hair of a yellowish-white color, which has a thick down-like under-growth closely packed beneath. This coat of soft fur is so long and thick, that it prevents the heat produced in the slow furnace of his body from escaping into the cold air. It answers the same purpose to him, that the snow-covered hut does to his human neighbors.

Men have no warm shaggy coats of this kind furnished for their use by nature, but they are enabled to supply the deficiency through the exertion of their own intelligence and ingenuity. They borrow warm covering from other creatures whenever they stand in need of such aid. Thus the rude human inhabitant of the ice land hunts and kills the bear and then before he feasts upon its flesh, he strips the fur robe from the carcass, and adapts it to his own naked body. So soon as the northern ice-people come out from their huts into the cold air, they put on coats and trousers of bear-skin, with the long sharp claws pointing out as toes to their boots. These odd savages look almost like small bears themselves when their white fur hoods are drawn over their heads, and their limbs are compactly muffled up in the claw-tipped robes which they have taken from the bodies of their prey.

Men in civilized lands do not put the skins of other animals upon their own bodies, but they do what is precisely the same thing in effect. They borrow silk from the worm, or cotton from the grass, or flax from the linen-plant, or wool from the sheep, and by their constructive skill, they spin and weave these substances into cloths, which are much more convenient than raw skins for the fabrication of garments, and which can be made as warm, when this is required. In every case, however, this artificial clothing acts in the same way as natural fur. It is warm, because it prevents the heat, which is produced in the slow furnace within the body from escaping quickly from the little chambers of the living laboratory. Clothing does not really warm the body, it merely keeps it warm; prevents it from being cooled as it would be if this covering were not placed between its surface and the outer air.

Warm bodies constantly grow colder, when situated in spaces which are more chill than themselves, provided always that there be no furnaces, quick or slow, within them, for generating new supplies of heat. They do so, because they give the excess of heat which they contain to the neighboring space, in the attempt to make it as warm as themselves. Warm bodies are always very generous, and disinclined to keep what substances near to them are less freely supplied with. If a metallic pint pot, filled with boiling water, be placed on the ground in air which has only the warmth of a March English day—some fifty degrees of the heat scale,—the water gets colder minute by minute until it remains no warmer than the air and ground which are around it. The rapidity with which warm bodies are cooled depends upon how much colder than themselves the space around them is. If one pint pot of boiling water be placed in out-of-door air that is cold as freezing water, and another be placed at the same time in a room where the air has the warmth of a mild summer day, the former will be deprived of all its excess of heat much sooner than the latter.

Warm bodies lose their excess of heat in two ways. They shoot it off into surrounding space. This is what learned men call “raying” or “radiating” it away. The sun, you know, shoots or rays its heat off to the earth, and so does the fire to your body when you stand before it. But warm bodies also communicate their heat to substances which touch them, provided those substances be colder than themselves. Place your hand upon a cold metal knob, and you will feel that your hand grows colder as it gives portions of its heat to the knob. This is what learned men call “conveying” heat.

[To be concluded.]