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 pass 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 pass 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 passes 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.