The following lines from Cowper furnish an apt illustration:

"Weak and irresolute is man;

The purpose of to-day,

Woven with pains into his plan,
To-morrow rends away."

The poet wishes to describe the want of resolution in man. But instead of saying simply, "He will abandon to-morrow what he purposes to-day," he expresses the same idea more elegantly by the use of a metaphor. The words woven and rends suggest the comparison between man, who first purposes and then abandons his purpose, and one who takes pains to weave a certain pattern and the next day has his work torn away from the loom. To-morrow puts an end to a purpose, at which to-day great pains have been employed, just as one might rend away from the loom a pattern carefully planned upon a previous day.

"The bow well bent, and smart the spring,

Vice seems already slain;

But Passion rudely snaps the string,

And it revives again."

Here the determination to conquer vice is compared, by suggestion, to an archer about to shoot a beast of prey; his bow is well bent, and the spring is smart, when the string is let go the bow springs back sharply. The weapon being in perfect order, the beast seems to be already slain, it is so certain that the shot will tell. But by some violence the string is snapt, and the beast rises up unharmed. So the mind is resolved and vigorous to overcome vice (like a well-strung bow), and seems to have already overcome it; but violent passion breaks in upon this resolution (as if the bowstring were snapt rudely), and vice is as strong as ever.

"Some foe to his upright intent

Finds out his weaker part."

Some tempter, wishing to do away with his right

intentions, finds out how to persuade him, as an enemy or foe finds out the weak part of a fortress he is about to attack.

"Virtue engages his assent,

But Pleasure wins his heart."

Here Pleasure and Virtue appear as two women, each of whom tries to win the affections of a man. He assents to what Virtue says, but his heart is won by Pleasure.

"Tis here the folly of the wise,
Through all his heart we view."

The words here suggest the notion of something which is purposely covered with a veil, which, however, is not sufficient to prevent us seeing through it. Art is like a covering, which a person who wishes to be thought wise throws over his folly

"And, while his tongue the charge denies,

His conscience owns it true."

These words may not, at first sight, appear metaphorical. But the word "charge" suggests the idea of a court of justice. The seemingly wise man is, as it were, put upon his trial for "folly." He denies the accusation, but knows in his conscience that the charge is true.

"Bound on a voyage of awful length

And dangers little known,

A stranger to superior strength,
Man vainly trusts his own.'

"

Man is compared to one who undertakes a long voyage without knowing its dangers, or being aware of any strength superior to his own, and yet trusting to himself without good reason.

By looking back to Cowper's poem it will be seen how briefly and how forcibly all these comparisons are suggested, and how aptly they illustrate the proposed subject. Such is the use of metaphor.

CHAPTER LVIII.

FIRST LESSONS IN GEOMETRY.

THE word "Geometry" is made up of two Greek words, which mean together Earth-measurement; and a Geometrician means, literally, "a person who studies the measurement of the earth."

When people first set about measuring the earth, they found it necessary to know something of lines and figures. So they began to study these things. Those who studied them did not always measure lands themselves, but the lines and figures were very useful to those who did.

Thus, for instance, they found out that if a line be drawn from one corner of a square to the opposite, it divides the square into two equal parts.

Again, they discovered how to draw lines of any length, and in any direction they pleased.

These and other such discoveries are very serviceable in measuring land. But they are also useful for many other things.

A carpenter who works by line and rule must know something of lines and figures.

A mason who plans or builds a house must know something of lines and figures.

The study of lines and figures is called the study of Geometry, and the person who learns and teaches it is a Geometrician. This person need not be either a land-measurer, or a carpenter, or a mason. But each of these must learn something of Geometry, and so must every one who draws anything, whether picture or plan. Besides, we all are constantly meeting with lines and figures of one kind or another, and it is in many ways advantageous to know something about them.

The first step in Geometry is to know the meaning of the terms we use. Every child has some notion what

a Circle is, but he may want an explanation of such words as Triangle or Parallelogram.

The explanation of such terms is called a Definition. If we say, "A triangle is a three-sided figure," that is a definition of a triangle.

Definitions.

A diagram is a drawing which represents lines and figures. The drawings in this lesson are diagrams. A plane surface, or a plane, is a surface perfectly level and even, like that of still water in a pond.

Parallel. Two straight lines are said to be parallel when they lie alongside of one another in the same plane, but never meet, however far they may be drawn. The two lines made in a road by the wheels of a carriage are parallel lines.

An Angle.-The word angle is derived from a Latin word, meaning "corner.' What an angle is, will be best understood by an example. Open a carpenter's two-foot rule, there is an angle between the two legs of the rule. The wider you open it, the larger the angle becomes, till at last the two legs are in the same straight line. Then there is no angle.

Observe that the size of the angle, or the width of the corner, depends upon how far the rule is opened, not upon the length of the legs. The length of the two sides of a room does not make the corner in which they meet greater or less.

Let there be two rules, the legs of the one six inches, of the other a foot long. Lay one on the other, joint upon joint, and open them together. There is one and the same opening-one corner, or angle. Remove the one ruler from the other as it is: there are two equal angles with sides of different lengths.

Take a long stick, and pin another to the middle of it, so that it can move round like the hand of a clock, and first let the moveable stick lie upon the other. Then

move it slowly round from left to right; there will be an angle between the two sticks on either side of the moveable stick. As you move the stick, one of these angles increases and the other diminishes. When the two angles are exactly equal, the one stick is said to be perpendicular to the other, and the angles on either side are called right angles.

An angle greater than a right angle is called an obtuse angle; an angle less than a right angle is called an acute angle.

CHAPTER LIX.

FIRST LESSONS IN GEOMETRY.

Definitions continued.

THE Area of a figure is the extent of its surface. A Triangle is a figure which has three sides, and therefore three angles.

The side upon which a triangle stands is called the Base of the triangle.