ever.

You cannot throw a stone in a straight line. If you could be at a great distance from this world and from every other, you might throw one in a straight line; and if there were no air, or ether, nor any world near enough to attract it, it would go on in a straight line, perhaps for When you throw stones or balls, they go in curved lines, and so do musket-balls and cannon-balls; so that, to hit an object, a marksman aims a little above it. We try to propel balls in straight lines onwards, but there is an uiseen power at work on the balls to draw them in straight lines downwards. That power is the loadstone attraction of the earth. Flying stones and balls act in obedience to both forees; and, taking their way between the two straight lines, they go in curved lines. For the same reason the moon goes circling round the earth, and the earth round the sun; and, as their forces are never spent, their motions never cease. Throwing stones in the streets is a very bad and dangerous practice.

In throwing, working, walking, and in all kinds of labour, you lose just as much force as you expend. When your force has been given forth so often and so long as to be all spent, you become so weak and so tired that you can do no more, until, by rest, and taking in more force in your food, you have recruited your strength. When you stand still, your force is expended in resisting the earth's loadstone force; and when you walk, run, and jump, you have to overcome, not only the earth's force of attraction, but the force of inertia in your own body also; so that your force is then spent more quickly. Horses, birds, and men have been known to die by attempting to work after all their force was spent.

Two thousand years ago Greek and Roman boys and girls played at hoops and tops; but no one, either then or now, could ever make a hoop or top stand upright while standing still. Your hoop will continue upright so long as you cause it to go at a rapid pace; and in spinning quickly, a top will even "sleep." The top stands erect as it spins, because the tendency to fall is then equal on every side; and it cannot fall so long as the tendency to fall on one side is balanced by an equal tendency to fall on the opposite. The spinning motion of a hoop produces much the same effect. The top of the hoop would fall if it could, for it is drawn downwards by the earth; but, before it can fall, it gets down to the bottom, and the bottom, which had no such leaning, mounts to the top, and thus the force of motion overcomes the force of attraction. The spinning force ceases, but the force of attraction never ceases, so that, when hoops and tops have no force to hold them un, they must lie down. The boys and girls of ancient times always whipped their tops. Peg-tops and humming-tops were not in use then. The hum of a humming-top is caused by the action of air on the little square opening in

the side. The air, as the top rapidly spins round, causes a vibration, as in an organ-pipe, and thus produces a sound.

Come, let us go to our swing. Here is a wonderful power! It is the power which works in all the clocks in the world, and keeps them from getting before time and lagging behind it. The swing is a pendulum. Cute, take your seat, and hold fast, or the old earth will draw you down from rather more quickly than will be pleasant or safe. Being now seated, the earth's loadstone force would hold you within the shortest possible distance from its surface if it could; but some one, by a pull or push, lifts you higher, by moving you from the centre. So soon as your body is free, the force of attraction draws it down to the centre again. But in the descent a new force is given to you; we call it momentum. It is strongest when you are at the lowest place. It is then O strong as to be able to force you along about as much further on the other side as you descended on this. As you return, the same force carries you up again as high as you first went; and, in going backwards and forwards, you swing like a pendulum, subject to two wonderful forces, which strive against each other, and which, by action and reaction, make this merry play in the swing, and useful work in the clocks. When you go up, the attraction quickly brings you down; but, in doing so, it creates a momentum, which carries you further than you would otherwise go. Attraction brings you down once more, and once more prolongs the little journey back. Thus you play with the two mightiest laws of the universe-laws by which worlds keep better time in their motions than any clock ever made by man.

momentum

Now, however quickly or slowly you swing to and fro, you cannot make more nor less swinging motions in a given time. Let one playfellow push you with all his force, that you may swing fast and high, while another counts the number of your swings, for a minute, by his watch; and then let your friend push you more gently, so that you shall swing slowly; and it will then be found that the slow motions and the fast ches are equal in number per minute. Quick swinging and slow swinging you through unequal spaces, and with unequal force, but they occupy equal time; so that on a swing of any given length you cannot swing more times nor less per minute or per hour. You may take longer or shorter journeys, and they will be quick or slow in proportion to their length, as they will also be long or short in proportion as they are quick or slow, and both will be in proportion to the propelling force; at in either case they will not be more or fewer in any given time.

bear

The number of swings per minute is determined, not by quickness of motion, but by the length of the swing. If it be short, you will wing to and fro more frequently, and less frequently if it be long. Should it be about thirty-nine and a half inches long in the perpen

14

per dicular, you would swing just once per second, or sixty times minute. That is the length of pendulums which beat once per second. If a pendulum work too slowly, we screw the ball up higher; and if too fast, we lower it. By the swinging of a chandelier from the ceiling or roof of a high building, we can tell the length of the chain and the height of the ceiling; for the motions per minute will be few in proportion to its length. How rapidly short pendulums work, as if they could not get on fast enough! but the long one works slowly, as if it were in no hurry. Both are "seeking rest, and find none."

There is so much science in some other playthings of children, that I will write about it again next month.

The Editor's Desk.

QUERIES AND

ANSWERS.

QUERY 1.-ON ONE OF THE GOSPEL MYSTERIES.

MR. EDITOR,-Respected Sir,-In 1 Tim. iii. 16 I find the Apostle Paul speaking about the great mysteries of the Gospel; and, among the mysteries, he mentions the preaching of Christ to the Gentiles. Now, It sir, why does the apostle call this a mystery? There may be mysteries in the Gospel I grant; but how can it be a mystery to preach it ? seems a very plain matter-of-fact, and it would please some of your readers to be informed how it can be called a mystery. Your explanaA CONSTANT READER. tion will oblige,

ANSWER.-It certainly is a plain duty to preach Christ, and the mystery does not consist in the simple work of preaching; but But the init consists in his being preached to the Gentiles. quirer may ask, How can it be a mystery that Christ should be preached to the Gentiles? Did not they, as well as the Jews, need the Gospel? and what mystery was there in giving it to them any more than in giving it to the Jews? Our reader must look at the question not merely as he sees it, but as a Jew would behold it eighteen hundred years ago, and then he will see in it a great mystery. The Jews had been for ages the peculiar people of God. They had been selected from the Gentile nations, and taken into covenant with God. "To them pertained the adoption, and the glory, and the covenants, and the giving of the law, and the service of God, and the promises" (Rom. ix. 4). But the Gentiles, meanwhile, were sunk in darkness and idolatry-strangers and aliens from the commonwealth of Israel. The Jews, elated by their privileges, thought

themselves the favourites of heaven, and the Gentiles as outcast from God. Therefore, for those depraved nations to be invited into God's covenant, and welcomed to Gospel privileges on equal terms with the Jews, was a great mystery to them. Moreover, the reception of the Gentiles into God's covenant involved the doing away with all the Jewish rites, sacrifices, and ordinances, and the entire breaking up and abrogation of the Jewish dispensation, though that dispensation had been ordained by God himself, and had been sigbalized by his special presence and glory more than a thousand years ago; indeed, the essential parts of its ritual had prevailed from the foundation of the world. The dissolution of this ancient and venerable institution was to the Jewish nation a great mystery. Read Eph. iii. 1-9, where the apostle speaks of it at large.

QUERY 2 HE THAT COMMITTETH ONE SIN IS GUILTY OF ALL.”

DEAR SIR,-I was reading some time ago that remarkable passage in St. James's Epistle, ii. 10, where the apostle says, "Whosoever shall keep the whole law, and yet offend in one point, he is guilty of all." How can it be, dear Mr. Editor, that if a man should commit one single sin he would be guilty of all?-Yours obediently,

common

C. W.

ANSWER.-The apostle does not mean that every sin is alike, or that to commit one sin is as bad as if a man committed all kinds of sin. But he means this:-1. That every sin is an insult to God's authority, and rebellion against the will and government of the great Lawgiver. 2. That as the whole law is comprised in the principle of love, so every sin is a violation of the law of love, and consequently is a breach of the whole law in its compendious summary; and 3. That any sin whatever contains in itself the germ of every other sin. Sin is the most prolific thing we can think of. Let a man commit one wilful sin, and at once he indulges a state of mind which begins to hatch every other form of iniquity. The seeds and germs are there, though as yet undeveloped in actual practice, and that God who gave the law penetrates the heart, and sees the nascent germs of the deadly vipers lurking in the soul. Behold what a brood of sins were involved, and almost in a moment developed, by the sin of Adam: unbelief, covetousness, contempt of God, sensuality, idolatry, alienation, selfishness, the loss of natural affection, and even cruelty towards the partner of his being; and this depravity, in the next generation, brought on Deism and fratricidal murder! Young people, keep from sin; for, however flattering it

may be, it is deceitful and deadly, and soon it biteth like a serpent, and stingeth like an adder.

QUERY 3.-ON POUNDING A FOOL IN A MORTAR.

DEAR MR. EDITOR,-I read of a strange practice in Prov. xxvii. 22, where it is said, "Though thou shouldest bray a fool in a mortar among wheat, with a pestle, yet will not his foolishness depart from him.” Was there, at any time, such a cruel practice? and, if so, how could it be possible for a man's folly to depart from him when he was being pounded to death? Your answer will oblige

ONE WHO LOVES THE "JUVENILE." ANSWER.-There was such a cruel custom among ancient nations, though we never read of it being practised among the Jews. Anaxarchus Democritius was thus put to death by the tyrant King of Cyprus. Indeed, this horrid death, too, was formerly inflicted by the Turks as a capital punishment. As to the question, How could a man be cured of his folly by a punishment that took away his life? we reply, Of course he could not. Nor does the wise man suppose such an absurdity. The sentence is a proverbial one, used to express the incurable character of a man of obstinate folly. The pestle and mortar were used among the Jews, not to kill men, but to bruise wheat, in order to separate it from chaff, that, being thus purified, it might become fit for food; but though means of the most powerful kind were used to separate the chaff of folly from some men, it still stuck to them-they were incurable. Of this, alas! we have too many proofs in the incorrigible folly and wickedness of many around us. Mercies will not melt them, and judgments will not drive them. They still continue in obstinate rebellion. But there is this awful sentence-hear it, ye children-" He, that being often reproved hardeneth his neck, shall suddenly be destroyed, and that without remedy" (Prov. xxix. 1).

QUERY 4.-How COULD GOD GIVE MEN STATUTES THAT WERE NOT GOOD?

SIR,-I read in Ezek. xx. 25 the following words-" Wherefore I gave them statutes that were not good, and judgments whereby they should not live." We always thought that God's statutes and judg ments were holy, just, and true; how, then, can it be said that God gave his people such as were not good? Will you please tell us where those statutes and judgments are to be found? A CONSTANT READER.

ANSWER.-They are not to be found at all, for the statutes of