« السابقةمتابعة »
partiels the heat and the
mists call precipitation; to which it answers in all its parts.
The air may be looked on as a clear and pellucid menstruum, in which the insensible particles of dissolved matter float up and down, without being discerned, or troubling the pellucidity of the air; when on a sudden, as if it were by a precipitation, they gather into the very small but visible misty drops that make clouds.
may be observed sometimes in a very clear sky; when, there not appearing any cloud, or any thing opake, in the whole horizon, one may see on a sudden clouds gather, and all the hemisphere overcast; which cannot be from the rising of the new aqueous vapours at that time, but from the precipitation of the moisture, that in invisible particles floated in the air, into very small but very visible drops, which by a like cause being united into greater drops, they become too heavy to be sustained in the air, and so fall down in rain.
Hail seems to be the drops of rain frozen in their falling
Snow is the small particles of water frozen before they unite into drops.
The regular figures, which branch out in flakes of snow, seem to show that there are some particles of salt mixed with the water, which makes them unite in certain angles.
The rainbow is reckoned one of the most remarkable meteors, though really it be no meteor at all ; but the reflection of the sunbeams from the smallest drops of a cloud or mist, which are placed in a certain angle made by the concurrence of two lines, one drawn from the sun, and the other from the eye to these little drops in the cloud, which reflect the sunbeams; so that two people, looking upon a rainbow at the same time, do not see exactly the same rainbow.
Of Springs, Rivers, and the Sea. Part of the water that falls down from the clouds runs away upon the surface of the earth into channels, which
convey it to the sea ; and part of it is imbibed in the spungy shell of the earth, from whence sinking lower by degrees, it falls down into subterranean channels, and so under ground passes into the sea ; or else, meeting with beds of rock or clay, it is hindered from sinking lower, and so breaks out in springs, which are most commonly in the sides or at the bottom of hilly ground.
Springs make little rivulets; those united make brooks; and those coming together make rivers, which empty themselves into the sea.
The sea is a great collection of waters in the deep valleys of the earth. If the earth were all plain, and had not those deep hollows, the earth would be all covered with water; because the water, being lighter than the earth, would be above the earth, as the air is above the water.
The most remarkable thing in the sea is that motion of the water called tides. It is a rising and falling of the water of the sea. The cause of this is the attraction of the moon, whereby the part of the water in the great ocean, which is nearest the moon, being most strongly attracted, is raised higher than the rest; and the part opposite to it on the contrary side, being least attracted, is also higher than the rest. And these two opposite rises of the surface of the water in the great ocean,
following the motion of the moon from east to west, and striking against the large coasts of the continents that lie in its way, from thence rebounds back again, and so makes floods and ebbs in narrow seas, and rivers remote from the great ocean. Herein we also see the reason of the times of the tides, and why they so constantly follow the course of the moon.
Of several Sorts of Earth, Stones, Metals, Minerals,
and other Fossils.
This solid globe we live upon is called the earth, though it contains in it a great variety of bodies, several whereof are not properly earth ; which word, taken in a more limited sense, signifies such parts of this globe as are capable, being exposed to the air, to give rooting and nourishment to plants, so that they may stand and grow in it. With such earth as this the greatest part of the surface of this globe is covered; and it is as it were the store-house, from whence all the living creatures of our world have originally their provisions ; for from thence all the plants have their sustenance, and some few animals, and from these all the other animals.
Of earth, taken in this sense, there are several sorts, V. g. common mould, or garden earth, clay of several kinds, sandy soils.
Besides these, there is medicinal earth; as that which is called terra lemnia, bolus armena, and divers others.
After the several earths, we may consider the parts of the surface of this globe which are barren; and such, for the most, are sand, gravel, chalk, and rocks, which produce nothing, where they have no earth mixed amongst them. Barren sands are of divers kinds, and consist of several little irregular stones without any earth; and of such there are great deserts to be seen in several parts of the world.
Besides these, which are most remarkable on the surface of the earth, there are found deeper, in this globe, many other bodies, which, because we discover by digging into the bowels of the earth, are called by one common name, fossils; under which are comprehended metals, minerals, or half metals, stones of divers kinds, and sundry bodies that have the texture between earth and stone.
To begin with those fossils which come nearest the earth ; under this head we may reckon the several sorts of ochre, chalk, that which they call black-lead, and other bodies of this kind, which are harder than earth, but have not the consistency and hardness of perfect stone.
Next to these may be considered stones of all sorts ; whereof there is almost an infinite variety. Some of the most remarkable, either for beauty or use, are these : marble of all kinds, porphyry, granate, freestone, &c. flints, agates, cornelians, pebbles, under which kind come the precious stones, which are but pebbles of an excessive hardness, and, when they are cut and polished, they have an extraordinary lustre. The most noted and esteemed are diamonds, rubies, amethysts, emeralds, topazes, opals.
Besides these we must not omit those which, though of not so much beauty, yet are of greater use, viz. loadstones, whetstones of all kinds, limestones, calamine, or lapis calaminaris; and abundance of others.
Besides these, there are found in the earth several sorts of salts, as eating or common salt, vitriol, sal
gemma, and others.
The minerals, or semi-metals, that are dug out of the bowels of the earth, are antimony, cinnabar, zink, &c. to which may be added brimstone.
But the bodies of most use, that are sought for out of the depths of the earth, are the metals; which are distinguished from other bodies by their weight, fusibility, and malleableness; of which there are these sorts, gold, silver, copper, tin, lead, and, the most valuable of them all, iron; to which one may join that anomalous body quicksilver, or mercury.
He that desires to be more particularly informed concerning the qualities and properties of these subterraneous bodies, may consult natural historians and chymists.
What lies deeper towards the centre of the earth we know not, but a very little beneath the surface of this globe; and whatever we fetch from under ground is only what is lodged in the shell of the earth.
All stones, metals, and minerals, are real vegetables; that is, grow organically from proper seeds, as well as plants.
Of Vegetables, or Plants.
Next to the earth itself, we may consider those that are maintained on its surface ; which, though they are fastened to it, yet are very distinct from it; and those are the whole tribe of vegetables or plants. These may be divided into three sorts, herbs, shrubs, and trees.
Herbs are those plants whose stalks are soft, and have nothing woody in them, as grass, sowthistle, and hemlock. Shrubs and trees have all wood in them; but with this difference, that shrubs grow not to the height of trees, and usually spread into branches near the surface of the earth; whereas trees generally shoot
up in one great stem or body, and then, at a good distance from the earth, spread into branches; thus gooseberries and currants are shrubs; oaks and cherries are trees.
In plants, the most considerable parts are these, the root, the stalk, the leaves, the flower, and the seed. There are very few of them that have not all these parts, though some there are that have no stalk; others that have no leaves ; and others that have no flowers. But without seed or root I think there are
In vegetables, there are two things chiefly to be considered, their nourishment and propagation.
Their nourishment is thus: the small and tender