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proper number of vibrations in relation to the other strings.

625. These seven notes, then, are the basis of all music; and, with the addition of five half tones, are the alphabet of music, and fill all the concordant intervals of one octave.

Octaves may, however, rise upon each other in successive ratios or degrees, as in the pianoforte, which has 5 and even 7 octaves; or 5 sets of natural notes as above, and 5 semi-tones, or flats and sharps to each octave.

626. For the purpose of obtaining further variety in composing tunes or melodies, these several notes may be played shorter or longer; and, in this respect, are divided as under: 2 minums make 1 semi-breve;

2 crochets make 1 minum;
2 quavers make 1 crochet;

2 semi-quavers make 1 quaver;

2 demi-semi-quavers make 1 semi-quaver; 32 demi-semi-quavers are to be played in the time of one semi-breve.

Again in regard to the tune itself, there are also two sorts of time, slow and quick, as common time and treble time.

627. When an agreeable succession of simple notes, having a perfect beginning and ending, is played or sung, it is called a tune, an dir, or melody; as a song, hymn, dance, or march, according to its several purposes.

When these notes, forming an air, are combined with corresponding uotes, in different ootaves, or on other instruments, and the whole is

scientifically made to produce a concordant and agreeable effect, it is called Harmony.

The bass and treble of a piano-forte played at the same time with the left and right hand, constitute the most common practice of har■mony.

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Some of Handel's pieces have been played by 1000 instruments and voices, all sounding harmoniously together.

Obs→The human soul may be moved in all its passions by music and as a soother of the mind, and a source of exquisite pleasure, the practice on some instrument cannot be too strongly recommended as a branch of liberal education to children of both sexes.

"When thro' life, unblest we rove.
"Losing all that made life dear,
Should some notes we used to love
"In days of boyhood, meet our ear;
"Oh! how welcome breathes the strain,

Wakening thoughts that long have slept,

"Kindling former smiles again

"In faded eyes that long have wept.

Like the gale that sighs along
* Beds of oriental flowers,
Is the grateful breath of song

That once was heard in happier hours,
Fill'd with balm the gale sighs on,

"Tho' the flowers have sunk in death,

"So when pleasure's dream is gone,

"Its memory lives in Music's breath." T. MOORE.

XXIX. Of Physics; or, the General Properties of Matter.

628. All existence is, what it appears to be to the powers of our senses; and is, therefore, relative, or comparative, to those powers.

Obs. 1. Thus, there is no intrinsic sweetness in sugari but the quality of sweetness is in the sense of the palate.

In a violet, there is no inherent colour; but the sense of colour called violet, is in our optic nerve; and the smell of sweetness produced by the same flower, is in the olfactory nerve.So, there is no sound in a vibrating string; but the sound, so called, is the vibrating effect produced on our auditory nerves.And the sense of kardness, or substance in a stone, arises from its being harder than our fingers, which have not power to pass through it. It has been a favourite notion of ancient and modern philosophers, that the substratum or basis of all matter is the same; and that all the varieties exhibited to our senses, are only so many modifications, capable of producing their respective sensible effects.

2. A person born blind, has no proper idea or conception of colours: he can feel the hardness, the roughness, and the length and breadth of surfaces; but he can have no perception of their various colours.--So, one born deaf, sees the motion of a bow on a violin, or the sticks on a drum but has no idea of their sound.--In like manner, all food is alike, in flavour, to those who have lost their sense of taste and smell.

629. The sensations produced by things out of ourselves, are called our perceptions; and the property or power of bodies to excite or create particular perceptions, is, in common language, considered as the perception itself; and the body is considered as possessing the sensation itself, which it usually creates in us.

Obs. Thus, we call vinegar sour, oil smooth, and fire hot: though the sense of sourness, smoothness, and heat, is in us, not in the bodies which create those perceptions. -So, likewise, in common language, we talk of the mo tion of the sun and stars; though it is only our earth that

moves.

630. Every collection, then, of properties, capable of affecting our senses, is called mate rial, or matter; and it possesses extension, or

bulk; solidity, or the power of maintaining its space; and divisibility, or the capability of being divided into infinitely small parts.

Obs. 1. Extension is infinite; at least, the human mind can set no bounds to it, but can add millions to millions of miles in every direction.

2. Solidity is a relative ideas and is measured by us in the ratio of the attraction, or centripetal force of the earth, called weight or gravitation. A cubic foot of pla tina weighs as inuch as 92 cubic feet of cork, or as 230,000 cubic feet of hydrogen gas; yet the platina itself may be light compared with other bodies unknown, and the cork and the gas be heavy in regard to others.

3. The property of infinite divisibility will be evidently, from the consideration that every particle of matter, however small, must have an upper and an under side.The infinite divisibility of matter is proved by the formation of animalcula, already treated of, and by the malleability of gold. Scents are equally subtle; and it is computed, that the millioneth part of a grain of musk divides itself into seven quadrillions of parts, in scenting a room. So, also, the light generated by a single grain of tallow, diffuses itself over a space two miles round, but it is doubted whether light is more than an undulation.

631. The followers of Sir Isaac Newton also ascribe to matter an innate principle of attraction for matter, and assert, that all matter attracts all matter at equal distances in proportion to the respective quantities. But a late writer, Sir Richard Phillips, maintains that the phenomena ascribed to innate attraction, is a mere accident of matter arising from transferred motions, of which ali matter is the patient.

Obs. 1.-Sir Richard Phillips, in his Essays on the Proximate Causes of the Phenomena of the Universe, observes, that Sir Isaac Newton first assumed and admitted the generally adopted principle of innate attraction as a specific central force; and then, invented another force

to counteract it, which second force be considered asacting on the planets simultaneously at right angies to he other, giving it the name of projectile force. These two forces he adopted as realities in nature, and to perpetuate the latter, he conceived space to be a vacuum,

Instead, however, of a system which has introduced into science such fanciful and arbitrary forces, Sir Richard Phillips is desirous of establishing a system of forces arising from the universal and analogous principle of MOTION, as it is transferred, by various coinbinations, from the greatest to the smallest portions of matter. He asserts, that all phenomena of matter are mere effects of transferred MOTION; and, that known Motions are competent to produce all phenomena.

MOTION, he says, is that universal principle which confers on masses of matter the power of acting on other masses. In regard to matter, which is essentially inert, it is the source of momentam, or potentiality, and is the animating soul of the material Universe. SPACE is the stage, MATTER is the subject, and Morton is the agent, producing all phenomena, Motion appeara, says he, to be the proximate agent of Omnipotence, and to 'be necessarily a direct emanation from the primary and eternal source of all power.

2. Instead of the words attract nud repel, which lead, says Phillips, to false notions of causes, he proposes to substitute the words to accede and to discede; and for at traction, accision; and for repulsion, discission, as expressing the mere acts of falling towards, and separating from. Instead also, gravitate or gravitation, he proposes to introduce, centripetate and contripetation.

3. Sir Richard then proceeds to shew that a stone which has been let fall to the earth is the patient of the twofold motions of the earth, the rotatory and orbicular and that these motions acting as forces on the stone, are competent to occasion it to fall to the earth. From this fact he deduces the following general conclusions --

That every body on the earth which has had any new direction of force given to it, is nevertheless subject to the permanent influence of the pre-existing orbicular and rotatory forces in the combined lines of their diree

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