formation as unworthy of belief, and conclude from what happens to our own bodies when immersed in water, that it would be impossible for any animal to live and breathe long in a watery medium!

The way in which fish live, their structure, their motion, and propagation, are very curious, and afford fresh proofs of the wisdom and power of God. That animals may live in water it is necessary that their bodies be very differently constructed from those which live only upon land. And this peculiarity we find when we examine the exterior and interior structure of fish. Why have most fish a slender thin body, flattened on the sides, and pointed towards the head, but to enable them to swim, and more easily cut through the water? Why are they covered with scales, if not that their bodies may be defended from the pressure of the water? Why are many fish, particularly those which are destitute of scales, enveloped with a smooth oily covering, but to preserve them from injury, and to keep them warm? Their bones are peculiarly light and flexible; their eyes are deep in their head, and their crystalline humour is spherical, that they may be secured from injury, and more able to concentrate the rays of light. Their fins are their only limbs, and by them they perform their different motions. By means of their tail fin, they move forward; their back fin directs the motion of their bodies; their breast fin enables them to rise, and their belly fin preserves their balance. The gills are their organs of respiration; they are placed behind their head; and there are four of them on each side; of which the uppermost are the largest. They continually take in water by their mouth, which is their inspiration, and evacuate it through the gills, which is their expiration. The blood which proceeds from the heart, and which passes through the veins of the gills, does not return through the lungs to the heart, as in terrestrial animals, but is directly distributed to every part of the body. The organ most essential to fish in swimming is the air-bladder enclosed in their belly, and communicating with their stomach. By means of this bladder, they can make their body more or less heavy; when it is inflated they become lighter, rise, and can swim near the surface of the water; but when it is contracted, and the air is compressed, the body becomes heavier, and sinks in the water. If the bladder is pricked with a pin, the fish immediately falls to the bottom, and cannot again rise to the surface.

The immense number of fish, and their great variety of shape and size, also merit our attention. In the waters of Germany only there are more than four hundred different species of fish; and how numerous must be the individuals of each species! Their figure also is much varied. We see among fish the greatest as well as the smallest animals. Some are long and fine as a thread; others short and broad; others are flat, round, triangular, &c. and some are armed with a horn; others with a species of sword; and others with a kind of saw. Some have nostrils through which they evacuate the superfluous water they have swallowed. We have in all this abundant cause to admire the power and wisdom of the Creator, so eminently displayed

in the formation of these animals, and to be grateful for his goodness in giving them all for our use.

SEPTEMBER XI.

OF THE PROPAGATION OF ANIMALS.

It was once supposed that vermin, insects, and even some quadrupeds, were generated from putrefaction, without the interposition of other animals of the same species; but this opinion, so contrary to reason, is refuted by the most incontestable experiments. It is now generally understood that all animals are capable of producing others, and that this propagation is generally effected in two ways; by eggs, and by producing the young ones alive. All animals that give milk, or of the class of mammalia, are viviparous. All birds are oviparous; but their eggs, before they are capable of producing young creatures, must be impregnated by the male. In most animals it is necessary for the male and female to unite together; fish only seem to be an exception to this rule. They have not been known to couple, but the male is supposed to impregnate the eggs after they have been spawned.

Fish are the most prolific of all animals; their multiplication is astonishingly great. It has been ascertained that the pike lays three hundred thousand eggs, the carp above two hundred thousand, and the mackerel near half a million. The eel is viviparous. Most amphibious animals propagate their species like others, except that some of them resemble fish in this particular. Some are viviparous, and others oviparous; the latter however do not hatch their eggs, but leave them to the warmth of the air, or water; and others deposite them in dunghills.

Worms are both viviparous and oviparous; most of them, if not all, are hermaphrodites, partaking of the nature of both sexes, with the power of self impregnation. The distinction of sexes is very evident in most insects; though in some no sex can be observed, and others seem to combine both sexes in one body. Insects are generally oviparous; though some are viviparous. The eggs of the former are hatched by the warmth of the air. The insect called the leaf-louse, or blight, is viviparous; an insect of this species taken at the time of its birth, separated from all intercourse with insects of the same species, and shut up perfectly alone, will nevertheless produce young ones. This takes place in the following manner: In spring, and during summer, the females of this class of insects bring forth their young without previous union with the male; they are then viviparous. A single one will produce a hundred more in less than than three weeks. All that are born in this season are females: the males are produced in autumn; at which time they couple, and the females lay eggs, which are hatched in spring. Thus one junction of the male and female

28*

2 R

produces several generations, the individuals of which are impregnated in their mother's eggs also.

When we reflect on this variety in the propagation of animals, we must be convinced of the power and wisdom manifested in an extraordinary degree. The instinct which leads the two sexes to unite together is truly admirable, and is a natural propensity, not produced by any external or adventitious circumstances. Most animals have a precise time for bringing forth their young, and every thing that is known with respect to this part of the animal economy displays an equal wisdom with the rest of nature's works; and we have great reason to be thankful that the different species of animals are preserved by means of that instinct, which induces them at certain periods to unite together for the preservation and continuance of their

race.

SEPTEMBER XII.

INFLUENCE OF THE MOON UPON THE HUMAN BODY.

Formerly certain influences were ascribed to the moon, tending to nourish superstition and occasion idle fears. The gardener would not plant till he had made observations on the moon, and the husbandman would not sow till he was assured of the happy influence of this planet. Those who were sick paid a strict attention to the variations of the moon, and even physicians regarded their influence as an object worthy of notice. As knowledge became more generally diffused. these prejudices began to disappear; and the influence of the moon is no longer considered so powerful and universal an agent in nature as was formerly imagined. The present age is less superstitious than the last; and it is the duty of every man to use all his exertions in separating truth from error, and to rescue his fellow-creatures from the despotic sway of blind superstition. With regard to the effects of the moon on the human body, some caution is requisite before we pronounce a decided opinion upon it; for totally to deny such an influence would be as irrational as to attribute to it a very great power and action. We must allow that the moon produces great changes in the air, and hence may occasion certain alterations in our bodies. The moon may cause, in the superior part of the atmosphere, such considerable motions and alterations, as to produce winds, heat, cold, exhalations, mists, &c. by which the health of our bodies may be greatly affected. It is observed that people labouring under certain infirmities experience exacerbations, and more acute pains, at the new and full moon. And if it is true that a cold moist air, and foggy stormy weather, have very different effects upon the body than a warm, dry, and serene air, it is by no means surprising that the moon has an influence upon our constitution, seeing that it so considerably affects the state of the air. The action then of this planet upon the

human body cannot be disputed, because it is founded on a certain principle, which is, that our health greatly depends upon the weather, and the constitution of the air we breathe, and these are materially affected by the moon.

In general we ought to admit it as a principle, to the glory of our Creator, that in all natural things there are certain connexions which influence the animal economy in various ways. There are doubtless in the atmosphere many wonders unknown to us, and which may occasion considerable revolutions in nature; and there may certainly occur many phenomena in the corporeal world which are influenced by the moon. The light reflected from her during the night is probably one of the least of the purposes she answers; and her being placed so near to the earth was perhaps to produce certain effects upon it, which the other planets could not do, because of their greater distance; for we have reason to believe, that every thing in our system has some relation to our globe. The beauty of the universe consists in the diversity and harmony of the several parts which compose it; in the nature of their effects, and in the total of happiness which results from the various combinations. If then we believe that God has arranged all, and established the connexions which exist among the spheres, we shall banish from our minds every superstitious fear of the influence of the moon and planets, and shall no longer suffer vain terrors to pervade our hearts; but we shall be convinced such ideas are contrary to divine wisdom; and as we become persuaded that he who governs all things with infinite goodness and power, operates only for the happiness of his creatures, we shall confide in him with certainty, and repose upon his parental regard with joyful and heartfelt gladness.

SEPTEMBER XIII.

THE MINERAL KINGDOM.

We require many materials to enable us to procure wholesome and convenient dwellings. If these materials had been scattered over the face of the earth, considerable inconvenience would have been experienced, and plants and animals would scarcely have had sufficient room. But happily our earth is free from such encumbrance. Its surface may be traversed by its inhabitants, or cultivated without any hinderance. Metals, stones, and several other substances which we continually use, are enclosed beneath our feet in immense receptacles, whence we extract them when we want them. These bodies are not concealed in the centre of the earth, nor are placed at an inaccessible depth; they lie beneath the surface, which covers them as a dome, and which, whilst it is sufficiently thick to produce nourishment for man, is thin enough to be readily dug through; so that we can obtain the substances contained in these vast storehouses of nature.

All the substances in the mineral kingdom may be divided into four classes, each having its distinguishing characteristic. The first class includes the earths. This name is given to such bodies as are not dissolved by water, fire, nor oil, which are not malleable, and bear the action of fire without losing any of their substance. This class, besides the simple earths, includes the stones which are composed of them. Of stones, there are two kinds, precious and common; the latter are the most numerous, and present us with masses differing in figure, colour, size, and hardness, according to their component parts. There is also a considerable diversity among precious stones, Some are perfectly transparent, and these appear to be the most simple; others are more or less opaque, according to their particular compo

sition.

Salts form the second class in the mineral kingdom. They are divided into acids, which are sharp and sour; and into alkalies, which impart to the tongue a bitter, burning, and lixivial sensation; these have the property of changing vegetable blues into green, whilst the acids convert blue into red. A certain combination and mixture of these two different salts, form what are called neutral salts. Among these is classed common or kitchen salt, which is extracted from the earth, or prepared from sea-water by evaporation. All these salts are one of the principal causes of vegetation. They also probably serve to unite and strengthen the parts of plants, as well as of other compound bodies; and they produce fermentation, the effects of which are so various.

The third class of the mineral kingdom comprehends those inflammable bodies, which are generally called bitumens. These burn in the fire, and when they are pure dissolve in oil, but never in water, They differ from other minerals, by containing more of inflammable matter, which renders those bodies in which it is found in a sufficient quantity combustible; and there is more or less of it in all bodies.

The fourth class contains the metals. These are the heaviest of all bodies; they become fluid if exposed to the action of a strong heat, and resume their solidity when cooled. They are resplendent and malleable. Some of them when melted in fire experience no diminution of weight, nor any sensible alteration; and these are called the perfect metals; of which there are three species, gold, silver, and platina. The imperfect metals are destroyed more or less readily by the action of the fire, and are converted into oxides, One of these, lead, has the property of being converted into glass, and of vitrifying all other metals, except gold and silver. The imperfect metals are five in number, viz. mercury or quicksilver, lead, copper, iron, and tin. There are besides other metals distinguished from these in being neither ductile nor malleable; these are called semi-metals, and are seven in number, platinum, bismuth, nickel, arsenic, antimony, zinc, cobalt.*

* The division of metals into perfect and imperfect, into metals and semi-metals, is now generally discarded. Since the author wrote the above, more metallic substances