Fables for Children, Stories for Children, Natural Science Stories Part 27

III.

If you magnetize a needle (holding it for awhile over a magnet), and attach it in the middle to a pivot in such a way that it can move freely around, and let it loose, it will turn with one end toward midday (south), and with the other toward midnight (north).

When the magnet was not known, people did not sail far out to sea. When they went out far into the sea, so that land was not to be seen, they could tell only by the stars and the sun where they had to sail. But when it was dark, and the sun or stars could not be seen, they did not know which way to sail. And a s.h.i.+p was borne by the winds and carried on rocks and wrecked.

So long as the magnet was not known, they did not sail far from the sh.o.r.e; but when the magnet was discovered, they made a magnetic needle on a pivot, so that it should move around freely. By this needle they could tell in which direction to sail. With the magnetic needle they began to sail farther away from the sh.o.r.es, and since then they have discovered many new seas.

On s.h.i.+ps there is always a magnetic needle (compa.s.s), and there is a measuring-rope with knots at the stern of a s.h.i.+p. This rope is fixed in such a way that when it unrolls, they can tell how far the s.h.i.+p has travelled. And thus, in sailing in a boat, they always know in what spot it is, whether far from the sh.o.r.e, and in what direction it is sailing.

MOISTURE

I.

Why does a spider sometimes make a close cobweb, and sit in the very middle of its nest, and at other times leave its nest and start a new spider-web?

The spider makes its cobweb according to the weather, both the present and the future weather. Looking at a spider, you can tell what kind of weather it is going to be: if it sits tightly in the middle of the cobweb and does not come out, it means that it is going to rain. If it leaves the nest and makes new cobwebs, it is going to clear off.

How can the spider know in advance what weather it is going to be?

The spider's senses are so fine that as soon as the moisture begins to gather in the air,--though we do not yet feel it, and for us the weather is clear,--for the spider it is already raining.

Just as a naked man will feel the moisture, when a man in his clothes does not, so it is already raining for a spider, while for us it is only getting ready to rain.

II.

Why do the doors swell in the winter and close badly, while in the summer they shrink and close well?

Because in the fall and winter the wood is saturated with water, like a sponge, and spreads out, while in the summer the water comes out as a vapour, and the wood shrinks.

Why does soft wood, like aspen, swell more, and oak less?

Because in the hard wood, in the oak, the empty places are smaller, and the water cannot gather there, while in the soft wood in the aspen, there are larger empty places, and the water can gather there. In rotten wood these empty places are still larger, and so rotten wood swells most and shrinks most.

Beehives are made out of the softest and rottenest wood; the very best are made from rotten willow wood. Why? Because the air pa.s.ses through the rotten wood, and in such a hive the bees feel better.

Why do boards warp?

Because they dry unevenly. If you place a damp board with one side toward the stove, the water will leave it, and the board will contract on that side and will pull the other side along; but the damp side cannot contract, because it is full of water, and so the whole board will be bent.

To keep the floors from warping, the dry boards are cut into small pieces, and these pieces are boiled in water. When all the water is boiled out of them, they are glued together, and then they never warp (parquetry).

THE DIFFERENT CONNECTION OF PARTICLES

Why are cart bolsters cut and wheel naves turned not from oak, but from birch? Bolsters and naves have to be strong, and oak is not more expensive than birch.

Because oak splits lengthwise, and birch does not split, but ravels out.

Because, though oak is more firmly connected than birch, it is connected in such a way that it splits lengthwise, while birch does not.

Why are wheels and runners bent from oak and elm, and not from birch and linden?

Because, when oak and elm are steamed in a bath, they bend and do not break, while birch and linden ravel in every direction.

This is again for the same reason, that is, that the particles of the wood in the oak and in the birch are differently connected.

CRYSTALS

If you pour salt into water and stir it, the salt will begin to melt and will entirely disappear; but if you pour more and still more salt into it, the salt will in the end not dissolve, and no matter how much you may stir after that, the salt will remain as a white powder. The water is saturated with the salt and cannot receive any more. But heat the water and it will receive more; and the salt which did not dissolve in the cold water, will melt in hot water. But pour in more salt, even the hot water will not receive it. And if you heat the water still more, the water will pa.s.s away in steam, and more of the salt will be left.

Thus, for everything which dissolves in the water there is a measure after which the water will not dissolve any more. Of anything, more will be dissolved in hot than in cold water, and in each case, when it is saturated, it will not receive any more. The thing will be left, but the water will go away in steam.

If the water is saturated with saltpetre powder, and then more saltpetre is added, and all is heated and is allowed to cool off without being stirred, the superfluous saltpetre will not settle as a powder at the bottom of the water, but will all gather in little six-edged columns, and will settle at the bottom and at the sides, one column near another.

If the water is saturated with saltpetre powder and is put in a warm place, the water will go away in vapours, and the superfluous saltpetre will again gather in six-edged columns.

If water is saturated with simple salt and heated, and is allowed to pa.s.s away in vapour, the superfluous salt will not settle as powder, but as little cubes. If the water is saturated both with salt and saltpetre, the superfluous salt and saltpetre will not mix, but will settle each in its own way: the saltpetre in columns, and the salt in cubes.

If water is saturated with lime, or with some other salt, and anything else, each thing will settle in its own way, when the water pa.s.ses away in vapour: one in three-edged columns, another in eight-edged columns, a third in bricks, a fourth in little stars,--each in its own way. These figures are different in each solid thing. At times these forms are as large as a hand,--such stones are found in the ground. At times these forms are so small that they cannot be made out with the naked eye; but in each thing there is its own form.

If, when the water is saturated with saltpetre, and little figures are forming in it, a corner be broken off one of these little figures with a needle, new pieces of saltpetre will come up and will fix the broken end as it ought to be,--into a six-edged column. The same will happen to salt and to any other thing. All the tiny particles turn around and attach themselves with the right side to each other.

When ice freezes, the same takes place.

A snowflake flies, and no figure is seen in it; but the moment it settles on anything dark and cold, on cloth, on fur,--you can make out its figure; you will see a little star, or a six-cornered little board.

On the windows the steam does not freeze in any form whatever, but always as a star.

What is ice? It is cold, solid water. When liquid water becomes solid, it forms itself into figures and the heat leaves it. The same takes place with saltpetre: when it changes from a liquid into solid figures, the heat leaves it. The same is true of salt, of melted cast-iron, when it changes from a liquid into a solid. Whenever a thing changes from a liquid into a solid, heat leaves it, and it forms figures. And when it changes from a solid to a liquid it takes up heat, and the cold leaves it, and its figures are dissolved.

Bring in melted iron and let it cool off; bring in hot dough and let it cool off; bring in slacked lime and let it cool off,--and it will be warm. Bring in ice and let it melt,--and it will grow cold. Bring in saltpetre, salt, or any other thing that dissolves in the water, and melt it in the water, and it will grow cold. In order to freeze ice-cream, they put salt in the water.

INJURIOUS AIR

In the village of Nikolskoe, the people went on a holiday to ma.s.s. In the manor yard were left the cow-tender, the elder, and the groom. The cow-tender went to the well for water. The well was in the yard itself.