respond to their kindred sound. A speaker will only affect his hearers in proportion as he is affected himself. He must, therefore, not only be a perfect master of the sense of his subject, but he must enter into the spirit of it, for no one can properly and thoroughly convey another's ideas unless he considers them his own. If he really feels what he utters, the tones of the voice and expression of countenance will obey such feeling.

The effect resulting from the delivery of any impassioned subject, not only depends on the tone of the voice, but also on the easy and graceful manner of the speaker; a few observations are, therefore, here made relative thereto, which are intended for the more juvenile reader.

On the delivery of any impassioned piece, the speaker should stand perfectly erect, his weight inclining on his right foot which should be a little in advance, and if the subject be of a solemn or dignified nature, his right hand should be extended with the palm inclining upwards, the left hand remaining gracefully by his side. Any particular emphasis should be marked by a corresponding stroke of the hand, and at the conclusion of every sentence, at the last emphatic word the hand should be allowed to fall.

The expression of any passion will require also a corresponding action and manner. Joy demands a buoyancy of manner with an animated action; Sorrow, on the contrary, requires a downcast look with a plaintive utterance, interrupted occasionally by sighs and tears. Love is expressed by a most beautiful serenity of countenance, and liveliness of manner, while Anger clenches the fist, and strains the muscles as if they were about to burst. But he that can identify himself with his subject, and follow the dictates of his own feelings in a judicious and well regulated manner, will not require set rules either for delivery or action, which are at best but inefficient; he will have nature herself for his guide, and under her direction he will not err.*

* For a more full and copious detail of the expression of the passions and the art of elocution generally, the reader is referred to the Rhetorical Speaker."

SCIENTIFIC READINGS.

ATTRACTION.

Attraction defined-Different kinds of attraction-Gravitation particular and general-Law of falling bodies-Electric, Galvanic, and Magnetic attractions-Attraction of Cohesion-Capillary attraction-Chemical affinity, simple and compound, &c.

ATTRACTION is a term used to denote that principle by which bodies have a mutual tendency to approach each other. Attraction may be divided into two kinds; that which extends to sensible distances, and affects bodies in the mass, as the attraction of gravitation, electric and magnetic attractions, and that which exists between the particles of bodies, as the attraction of cohesion and chemical attraction.

The attraction of gravitation is again divided into particular and general gravitation. Particular gravitation or gravity is that which respects the action of the earth on different bodies. All bodies by virtue of this principle appear to have a tendency towards a point in or near the centre of the earth, which point is necessarily fixed, otherwise its changing its position, in ever so trifling a degree, would cause the land to be overflowed by the ocean on that side of the globe to which it might approach. The force of gravity is found to be nearly equal at all places equidistant from the earth; it also affects all bodies in a like degree, the resistance of the air* alone preventing bodies of a loose structure from falling with the same velocity as bodies of a more dense and compact nature.

In a vessel exhausted of air, a piece of metal, as a sovereign, and a feather, are found to fall with a like velocity.

The power of gravity is greatest at the earth's surface, whence it decreases both upwards and downwards, but not in a like ratio; it decreases upwards in proportion to the square of the distance from the centre of the earth, while it decreases downwards in a direct ratio of the distance from the earth's centre. Thus a body at the distance of one semidiameter of the earth above its surface, or at a double distance from the earth's centre, will be acted on by a force of only one quarter of what it would at the surface; while a body at half the distance of the earth's semidiameter from its centre will be acted on by a force of one half of what it would on the surface.*

1

General or Universal gravitation is that which relates to the attraction of the sun, moon, and planets, and other heavenly bodies, and by which they are preserved in their orbits. According to the Newtonian theory, the action of the sun on the earth produces its centripetal force, and prevents it from flying off in a tangent to its orbit; while at the same time the earth produces a similar action on the sun. The earth also acts in a like manner towards the moon, and retains her in her orbit, while itself gravitates towards the moon. Thus all the secondaries gravitate towards their primaries, and the primaries towards their secondaries, and this in a degree proportioned to their mass combined with the squares of their distances. This action and reaction of the heavenly bodies have been found, by observations on the double stars, to extend to the most remote regions of the heavens.

Electricity has the property of causing bodies to possess

*It has been found by experiment that the quantity of descent of a falling body, is in proportion to the square of the time; thus a body will fall 16 feet during one second, 64 feet during two seconds, 144 feet during three seconds, and so on in proportion. The quantity of descent during each second increases according to the ratio of the odd numbers 1, 3, 5, 7, &c.; thus it will be 16 feet during the 1st second, 48 feet during the 2d second, 80 feet during the 3d second, and 112 feet during the 4th second. A body will take the same time in travelling over a curve as it would in making a perpendicular descent; thus a ball propelled from a cannon planted on an eminence, will strike the ground, if level, at the same moment it would have de

from the cannon's mouth,

an attractive influence. If a glass ruler, or stick of sealing wax, be rubbed with any soft warm substance, as flannel, fur, or woollen cloth, it becomes excited, and on being presented to any light body, as pith, paper, &c., it will cause it to fly towards it.

Galvanism is of a similar nature to electricity, but its influence is exerted rather in the way of decomposition. The cause both of electric and galvanic action has not yet been satisfactorily determined by philosophers.

Magnetic attraction is also of a similar character to electric attraction; indeed, electricity, galvanism, and magnetism, seem very intimately connected. The attractive power of the magnet was known to the ancients, although they were not aware that a needle, or thin piece of iron, rubbed with it, would give it the property, when suspended, of pointing towards the poles. The magnet, aided by galvanic action, has been recently found to possess enormous power; that in the Adelaide Gallery has been made to support a weight of more than 400 lbs.

The second kind of attraction is that which exists between the particles of bodies, as the attraction of cohesion, and chemical attraction, or affinity. When the force of attraction operates on atoms of the same species, it is called the attraction of cohesion, or of aggregation; and when on atoms of different substances, it is called chemical attraction, or affinity.

By Cohesion is meant that power by which the atoms of bodies are united together, of which there are different degrees. The atoms of a stone cohere more firmly than those of jelly, and the atoms of jelly more than those of water, and the atoms of water more than those of air. The cause of this has been reasonably attributed to the shape of the atoms; those that cohere most firmly being as it were of a dove-tailed shape, so as to render the mass compact and firm. The spherical shape of drops of water, as also of particles of quicksilver, has been attributed to this kind of attraction. The chief anthe attraction of cohesion is het.

water or other liquid in small tubes,

called Capillary* attraction, has been considered by some a species of the attraction of cohesion. Thus, if a glass tube of very small bore, open at both ends, be immersed in a vessel of water, the water will be found to rise higher than its natural level. If a piece of sugar or salt be placed upon a drop or two of water, the water will, by virtue of this attraction, continue to rise in the sugar or salt until it be entirely wet. Also the ascent of water to the branches of trees by means of their roots, is attributed to this kind of action. Chemical attraction, or affinity, is that principle on which the various operations of chemistry depend. The art of chemistry exerts itself to destroy the cohesion of bodies, and to form other substances by means of new attractions. Most bodies combine only in certain proportions, and with certain other bodies; and when combined they acquire new properties, and cannot be separated by mechanical means. There are two kinds of chemical attraction, simple and compound attraction.

Simple attraction, or affinity, is when two substances unite together in consequence or their mutual affinity; thus, spirits of wine will dissolve camphor and hold it in solution, and the solution will be perfectly clear until some other substance be for which it has a greater

affinity than it has for

stance, a little of thor; water is such sub

being poured into the solution, the spirits of wine will leave the camphor to unite with the water, and the camphor will fall down in flakes.

Compound

decompose affinity is when two compound substances

other, and produce two or more new compounds. If a solution of muriate of baryta be mixed. with a solution of sulphate of soda, the sulphuric acid of the sulphate of soda, by attracting the baryta of the muriate of baryta, will form a sulphate of baryta, while the soda, by attracting the muriatic acid, will form muriate of soda,

*Sir Richard Phillips ascribes that which is generally called capillary attraction to the same principle as that by which water is raised in a pump, or mercury in a barometer. He observes, that the pressure which is intercepted by the intervening sides of the immersed solid, is relatively increased on the intercepted side; and that it is this import ant principle of intercepted pressure which occasions a plumb,line to incline towards a mountain, and boats to congregate about a ship, and small corks about a bung; whereas, if the bung were as dense as the water, and floated below the water, the corks would not be acted upon.