SPRING OF THE AIR.

3

those principles of life and of growth with which the Creator has so bountifully endowed his creatures; and though we use the word spring as the general name for the season, yet the peculiar and proper meaning of it is, the exertion of those powers wherewith plants and animals are endowed.

When we look around us, and give our calm and serious consideration to every thing that we see, we cannot fail to discover that spring, or elasticity, is the grand source of all material action; and that our contemplation of it is final as regards created things, and brings us immediately to the acknowledgment and the adoration of our God.

Let us return to the spring or elasticity of the atmospheric air, which air is the breath of life to us while we are in the body, and consider very briefly the part which it performs, under God, in the grand economy of terrestrial nature. So delicate is this spring of the air, that it yields to the gentlest pressure, and returns to its former state the instant that this pressure is removed. Heat makes it vibrate far more sensibly than the most delicate balance which can be constructed by mortal hands; and, as we shall afterwards have occasion to notice, those vibrations are the immediate causes of those changes of seasons which make the year so delightfully varied. The air presses as a spring, and at the same elevation from the earth's centre, and under the same action of light and heat, it presses equally in all directions, upwards, downwards, and laterally. Its average rate may be estimated at about fifteen pounds of our common avoirdupois weight upon every square

4

SPRING OF THE AIR.

inch of surface; so that the body of a man of ordinary size is supported by a spring or pressure of about thirteen tons. This pressure acts so equally upon all sides, that it always ministers to protection. On this account, when a man falls, the spring of the air lets him down gently; and were it not that he is surrounded by this all-yielding, yet all-resisting substance, one tumble to the earth would break him like a potsherd.

Every thing else is supported in a similar manner by the spring of the air; and were it not for this spring, the plants, and even the buildings would fall prone upon the earth-no winged creature could make its way through the air-and the world, and all its kingdoms, would be motionless, and, by necessary consequence, dead.

Without this spring of the air, we could have no well-spring of water from the rock; and our pumps, our steam-engines, and our furnaces, by which the stubborn earth is converted into metal, and civilized man turns the contents of the deep-seated mine into the ploughshare, the pruning-hook, and every tool of the artificer, would be in vain; for in all these, and in countless other cases, it is the means which we possess of winding up the spring of the air, and again allowing that spring to recoil and unbend itself, which enables us to carry on our working.

The spring of a watch, a clock, or any other moving instrument, is another remarkable illustration of the use of this extraordinary word. In all such springs, there is a power inherent in the spring itself, capable of performing its operations without the immediate

SPRINGS OF A WATCH.

5

intervention of man. The two principal springs of the watch are not only curious in themselves, but they are capable of being made the means, or the memorials, of some useful instructions. They are both made of steel, and steel acquires its springiness by being hammered on the anvil, thereby shadowing forth to us that the more the spirit of a man is hammered on the anvil of adversity, the more elastic it should become in returning to the true line of rectitude. God hath been graciously pleased to give us the steel when he "breathed into our nostrils the breath of life," the very emblem of elasticity, or the rebounding or recovering power of a spring. That he hath seen meet to try us in the furnace of worldly affliction, and to beat us on the anvil of worldly care, should only teach us to be grateful to Him for having implanted in us that which can be purified in the fire, and gain strength and elasticity under the hammer.

Of the two springs of the watch or clock-for the principle is the same, whether the instrument is portable or not the one is called the main-spring. It is a narrow ribbon of steel, coiled up in a little brass box. The axis or arbor of the box is fixed in the frame-work of the watch, so that, though the box turns round upon it, it does not itself turn round. One end of the spring

is fastened to this, and the other

end is fastened to the

circumference of the box. In winding up the watch, the box is turned round by the chain being coiled upon another piece of the machinery, which is called the fusee, and the effect of this is to wind the spring tightly round the arbor, and so treasure up its elasticity to be

used as a power during all the interval between the windings of the watch. When the key is withdrawn, the spring reacts, pulls the chain again from the fuzee, puts the whole wheelwork of the watch in motion, and would run it down in a little more time than is occupied in winding, were it not for the counteracting influence of another spring.

This last is the balance-spring, and there is a beautiful, and by no means an uninstructive moral, in the effect which it has in restraining the impetuosity of the other. The balance-spring is usually seen on that side of a watch which is opposite to the dial. It is a small steel wire, very elastic, and coiled round and round the balance with a number of turns, at some distance from each other. In fine watches, it is an exceedingly delicate piece of mechanism, and in order that it may vibrate to an equal extent in the smaller coils as in the larger ones, it has to be fashioned with a degree of nicety which no instrument can measure, but which must depend alone upon the hand of a workman of the utmost skill and experience. There is something worthy of remark in this: the hand is an instrument of God's making; and, worthy of its maker, it can perform operations far more delicate than can be performed by the nicest instruments that man can construct. Hence, as God has bestowed upon us the glorious gift of this hand, a gift which is quite unrivalled among the things of this nether world, surely we ought to employ it, and that with all diligence, in promoting his glory, and the good of his creatures.

This balance-spring does not, like the main-spring of

OF A WATCH.

the watch, exert one continued influence.

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It is acted

upon and overcome, and it again reacts and overcomes the power which overcame it; and this is that which regulates the motion of the watch. In a common watch, for we need not fatigue ourselves with those of more elaborate construction, there are two little levers, called pallets, projecting from the arbor of the balance, and forming an angle with each other. These lock into the tooth of the balance-wheel, and were it not that from the form of these teeth they bear more on the one side than on the other, they would hold it fast. But in consequence of the unequal pressure produced by this means, the tooth of the balance-wheel, urged on by the train of the watch, from the moving power of the main-spring, presses the one pallet, and coils up the balance-spring, so that the tooth escapes from the pallet. The instant this takes place, the balance-spring is free, and it recoils, by the force of its elasticity, and seizes and stops another tooth of the wheel with the opposite pallet; and it is not till the power of the mainspring has accumulated some effort upon the train, that the wheel can pass another tooth, or the watch make another beat, as it is called. Thus, between the constant action of the main-spring, and the alternate bending and unbending of the balance-spring, the watch goes regularly, according as it is constructed and set; and if either of these springs should fail in the performance of its office, the watch would become a useless toy. We have entered somewhat at length into the explanation of the springs which move and regulate this most useful little instrument, because they are not