a family of love had this world contained, if sin had not introduced hate, and destroyed the scene of joy. But love can restore it,-nay, love is restless till it is restored. The God who has formed the paternal affections, offers himself as our Father, not only in his paternal character of Creator, but in the far more costly and more endearing character of Redeemer. Love contrived the plan of our rescue. Love executed it. Love urges it upon us. Love waits to bestow it. We are dull and slow. Hark! he hastens us. "Return unto me, and I will return unto you, saith the Lord." "Ye shall be mine in the day that I make up my jewels." "I hate putting away." "I will heal your backslidings, I will receive you graciously, and love you freely." Will you not try, my reader, to aspire at this nobler new and filial attachment? your nature, your heart will become enriched by emotions, to which it is now a stranger,-cleared of pangs which now harass and torment it,—and inspired by hopes, which the reality will far surpass. Look then to Jesus, and, through him, to your reconciled Father; and then shall you know of a truth what it is to be loved, protected, guided, and provided for, by Parental Affection. M. G. L. D.

parentage, to obtain this With this new element in

SIXTH WEEK.-MONDAY.

BIRDS. RELATION OF THEIR BODIES TO EXTERNAL NATURE.

THE evolution of the chick in the egg, may be taken as an example of the earliest processes of animal organization in general, because, such is the analogy of nature, that the plan by which the embryo of all the higher species of animals is developed, whether in the egg or in the womb, is nearly the same. But there are certain peculiarities in the form and modifications of the bodies of birds, intended to suit them for the element in which

they are destined to move, which are very striking as indications of design; to which, before leaving the subject of organization, it is desirable to advert. I take the general scope of the argument from Paley, with the illustrative observations of Sir Charles Bell.

Birds are intended for the very peculiar function of raising themselves above the earth, and transporting themselves from place to place, through the air; an achievement which must appear, at the very first glance, to require a peculiar conformation of body. We are familiar with this action of birds, and are therefore apt to pass it over without much observation; but if any one, divesting himself of his previous knowledge, could sit down to try, without the aid of experience, how the matter could be managed, he would soon find that the problem was by no means an easy one. The first thing which would strike him, would be the difficulty of causing a body, specifically heavier than the atmosphere, to float in that element. If this were overcome by the aid of dynamics, he would immediately find other questions arising, for an answer to which, that science must also be appealed to; the means of equipoise and voluntary progression, the best mechanical contrivances, at once for lightness, and for strength of structure, the power, and the forces most skilfully adapted for cutting the air, passing through it with pleasure, in all directions, for resisting the current of the wind, and flying against it; the most advantageous conformations of the external covering of the body; the shape of the wings best calculated for soaring, for rapid flight, for alighting, for fitting gracefully and easily to the body, when at rest, all these, and a thousand other inquiries would occur to him, involving the laws both of solids and of fluids, till he would find himself lost in the intricacies of the subject, and be forced to confess that he who could conquer all its difficulties, must, to say the very least, be possessed of no ordinary accomplishments. Now, all these questions have certainly been considered, and

solved, in forming the body of a bird, with relation to its aërial functions. Let us look at a few of them.

The first query is, How a creature, which has to exercise the same animal functions as quadrupeds, shall be able to rise into the air. Contrivances must, of course, be resorted to, for rendering its body as light as is consistent with other conditions. What has actually been done with this view. In the first place, the body of the bird has been enlarged, without increasing the weight in nearly the same proportion The windpipe of the

swan and crane is adduced, by Sir Charles Bell, as an instance of this; and he has given a drawing illustrative of the curious convolutions which this member undergoes, within the sternum or breast-bone of the bird. “The light and hollow air-tube fills a space in the interior of the bone, by which the surfaces are extended for the attachment of the muscles of the wings, and thus two objects are attained through it."*

But there is a still more curious provision for the extension and magnitude of the body of a bird, independently of weight. In birds, the air does not only pass into their lungs, but through them, so as to fill a series of air-cells, composed of fine membranes, which are interwoven with all the intestines. The heart is surrounded with such a cell. Two great cells are attached to the liver; and, in the same manner, are all the viscera of the abdomen interspersed with air-cells, and these all communicate. The air, thus admitted into the interior of the body, extends even into the bones.

"In comparing the bones of animals," says Paley, we are struck, in the bones of birds, with a propriety, which could only proceed from the wisdom of an Intelligent and Designing Creator. In the bones of an animal that is to fly, the two qualities required are strength and lightness. Wherein, therefore, do the bones of birds (I speak of the cylindrical bones), differ in those respects from the bones of quadrupeds? In three properties; * Appendix to Paley's Natural Theology, Knight's edition, vol. ii. p. 279.

first, their cavities are much larger, in proportion to the weight of the bone, than in those of quadrupeds; secondly, these cavities are empty; thirdly, the shell is of a firmer texture than is the substance of other bones. It is easy to observe these particulars, even in picking the wing or the leg of a chicken. Now, the weight being the same, the diameter, it is evident, will be greater in a hollow bone than in a solid one, and with the diameter, as every mathematician can prove, is increased, cæteris paribus, the strength of the cylinder, or its resistance to breaking. In a word, a bone of the same weight would not have been so strong in any other form ; and, to have made it heavier, would have incommoded the animal's flight."

Connected with the subject of weight, is the contrivance of making birds oviparous, by which means the important work of gestation goes on with as little increase as possible of the weight of the body. It is well known, that birds of prey sometimes gorge themselves to such excess that they are unable to rise on the wing, a proof that the burden of offspring in the womb, would have been unsuitable to the purposes of flight. The advantage, in this respect, of an oviparous procreation is, that, while the whole brood is hatched together, the eggs are excluded singly, and at considerable intervals.

In

Paley draws an argument for design, by comparing animals with regard to their instruments of motion; and here also the contrivances which fit the bird for its peculiar motions, are very admirable and peculiar. comparing feet, wings, and fins, he exclaims, "I desire any man to say which of the three is best fitted for its use, or whether the same consummate art be not conspicuous in them all.”

After noticing the striking analogy which subsists between a wing and the fore-leg of a quadruped, he goes on to say:-" But, fitted up with its furniture of feathers and quills, it becomes a wonderful instrument, more ar

Paley's Natural Theology, Knight's edition, vol. i. p. 277.

tificial than its first appearance indicates, though that be very striking. At least the use which the bird makes in flying, is more complicated and more curious than is generally known. One thing is certain, that if the flapping of the wings, in flight, were no more than the reciprocal motion of the same surface, in opposite directions, either upward or downward, or estimated in any oblique line, the bird would lose as much by one motion as she gained by the other. The sky-lark could never ascend by such a motion as this; for, though the stroke upon the air, by the underside of the wing, would carry her up, the stroke from the upper side, when she raised her wing again, would bring her down." Having started this difficulty, our author proceeds, by a description of the form of the wing, and the action of the muscles and joints of the pinions, to show how successfully it is obviated, and how distinctly there is exhibited in this mechanism, evidences of skilful contrivance. He then speaks of the tail as an instrument of steerage, and adds, "Herein we meet with a circumstance not a little remarkable. Birds with long wings have short tails; and, in their flight, place their legs close to their bodies, at the same time stretching them backward as far as they can. In this position, the legs extend beyond the rump, and become the rudder, supplying that steerage which the tail could not.'

In another part of his work, Paley gives his celebrated description of a feather, in which he demonstrates that it is, for strength, lightness, elasticity, and resistance to the air, what he happily calls a mechanical wonder. I must not occupy so much room as would be necessary for doing justice to this admirable analysis; and shall conclude with the animated observations with which he introduces it. "The covering of birds cannot escape the most vulgar observation: its lightness, its smoothness, its warmth, the disposition of the feathers, all inclined backward, the down about their stem, the overlapping

Paley's Natural Theology, Knight's edition, vol. i. p. 280, 281.