It is united to the hip by a ball and socket joint, as is the upper bone of the arm at the shoulder blade. But the socket at the shoulder is shallow; while that of the hip is the deepest in the whole body. "This," says Dr. Paley, "agrees well with the duties assigned to each part. The arm is an instrument of motion principally, if not solely, and accordingly requires a shoaler socket to allow it a freer play. Whereas the thigh bone forming a part of the column of the body, having to support the body, firinness was principally to be consulted." Upon natural principles, however, the deeper socket ought to have been at the shoulder. At the hip, the pressure of the bone is never against the bottom of the receptacle, so as to tend naturally, as one might say, to deepen the cavity. At the shoulder, on the contrary, the head of the arm always forces into the cup in which it moves. The neck of the thigh bone is bent over, and enters side ways. Consequently, there is no pressing inward at this joint. We see why the hip socket should be made deep to prevent the bone from thrusting by, as it is not directly under the support: that is, we see the wisdom of God, but we discover no other cause. Every natural tendency that we can conceive of, would have been precisely the reverse. The same remark will apply to instances without number in the animal frame, where a happy construc tion is apparently the opposite of a natural effect, and can only be referred to a designing Intelligence.

This figure exhibits the neck of the femur or thigh bone bent over, and inserted by the head into the socket at a.

Figure 14.

B.

This is certainly very skilful and striking; but I would ask why the necessity of the oblique position of the thigh bone?

T. If you will endeavor in walking to place it in a straight position, by keeping the feet so far apart that the limbs shall be perfectly parallel to one another and perpendicular to the ground, you will find it produces a rolling effect when you rise from one foot to the other, as if mounted upon stilts. This is relieved by the dishing or oblique direction of the bones-and you will perceive it could be avoided in no other mode. Dr. Bell, in the Library of Useful Knowledge, has some curious remarks upon the form and position of the thigh bone, shewing how it is calculated for strength in consequence of the obliquity, and in which he compares it to the dishing of a wheel.

But there is another provision in this remarkable

structure which invites our attention,-the manner in which the hip joint is secured.

A. The joints in general, are united by means of a strong band of gristle encompassing the heads of the bones. This is the case in the ball and socket joint at the shoulder. If a mechanic wanted to fasten a ball into a cup, so as to allow free play to the ball, he would adopt the same measure. Now, it is wonderful to observe, that in addition to this security, the hip, a far more important joint than the shoulder, and more dangerous to be dislocated, and from the position of the neck of the bone, more liable to dislocation, exhibits an additional security, and a more mechanical, artificial contrivance one might be challenged to imagine. It is this: a short, strong, yet pliable ligament, resembling a leathern thong, is inserted by one end into the head of the bone, and by the other into the bottom of the socket.It is hardly practicable to break it. It will scarcely admit of being even extended. Its situation is such that it cannot be cut, without cleaving the bone. Whoever will reflect upon this single provision, taking into view its singular importance to this joint, and that it is not generally assigned to the other joints, and then how precisely it is what our own expedient would have been in a similar case, must be disposed to say with Paley, "It is an instance upon which I lay my hand. For the purpose of addressing different understandings, and different apprehensions, for the purpose of sentiment, for the purpose of exciting admiration of the Creator's works, we diversify our views, we multiply examples; but, for the purpose of strict argument, one clear instance is sufficient; and not only sufficient, but capable, perhaps, of

generating a firmer assurance, than what can arise from

a divided attention."

Fig. 16.

A part of the hip joint is here taken off for the purpose of exhibiting the round ligament, a, which is seen connecting the head of the thigh bone with the bottom of the socket. It allows considerable latitude of motion, at the same time it is the great safeguard ugainst dislocation It is hardly imaginable how great a force is necessary even to stretch still more to break this ligament ;yet so flexible is it, as to oppose no impediment to the suppleness of the joint.

T. We will now close the description of the bones and joints, with another striking instance of wisdom and design in the formation of the foot.

A. The FOOT is composed of thirty-six little bones, united together by gristle, a very elastic substance under a hard pressure. So many joints impart the advantage of a spring-and of enabling the foot to conform itself to the surfaces of objects upon which we tread. Any one must be sensible of the inconvenience of a wooden foot; and the inconvenience would be, it would have no spring; and would be incapable of suiting its shape to the inequalities upon which we stand or walk. But the number of bones is only a part of this admirable mechanism. The arching of the foot is an obvious proof of contrivance. If the bottom of the foot was perfectly flat, it is plain, it must have had a heavy

and uncomfortable effect. One may easily perceive this, by lashing the bottom of the foot to a strip of wood. There could be no spring with a flat foot. But as the construction is, the two extremities only of the foot rest upon the ground, while the elastic arch in the centre yields to the pressure, and causes the weight of the body when we walk, to play, as it were, upon a constant spring.

B. We now see the use of the heel, and it is a use which one would not immediately think of. It helps to form the ankle. arch.

T. But this is not all the use.

A. The heel is not directly under the leg; but extends back like a spur, and is united to the main body of the foot, by a very firm, but still a considerably springy joint. The effect of this is, when the heel touches the ground in walking, and it touches first,-in consequence of its being formed like a spur, and having a spring at the same time, the whole weight of the body does not come down with a sudden jolt ;-there is not only a yielding in the point of support, but we descend in a curve, the centre of which is the ball of the heel. If it were not for this contrivance, we should always walk as upon stilts. The leg would strike the ground, like a cane. Fig. 15.

In this figure the foot is represented as descending to the ground in a semicircle from the point of the heel, Owing to this circumstance, in connexion with the elas ticity of the parts, the force of the blow is diminished.

T. Are there any peculiarities in the feet or limbs