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proper number of vibrations in relation to the other strings.
6526. These seven notes, then, are the basis of all music; and, with the addition of five half toncs, 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 piawoforte, which has 5 and even 7' octaves; or 5 sets of natural notes as above, and 5 semi-tones, or tlaws and sharps to each octave.
626. For the purpose of obtaining further variety in composing tunes or melodies, there several notes may be played shorter or longer : and, in this respect, are divided as under:
2 minums make 1 semi-breve;
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, hyman, dance, or march, according to its several purposes.
When these notes, forming an air, are combined with corresponding uutes, in different ootávcs, or on other instruments, and the whole is
scientifically made to produce a concordant and agreeable effect, it is called Flarmony.
The bass and treble of a piano-forte played at the sanje time with we left and right hand, constitute the most common practice of har. TRONY.
Some of flandel's pieces have been played by 1000 instruments and voices, all sounding harmoniously together.
Obs The naman soul may be moved in all its passions by musie ; and as & soother of the mind, and a source of exquisite pleasure, the practice on some instrument can. not be too strongly recommended as a branch of liberal education to children of both nexes.
* When thro' life, onblest we rove.
"Losing all that made life dear,
“ In days of boyhood, meet our ears
. Wakening thoughts that long have slept,
" In faded eyes that long have wept.
* Beds of oriental flowers,
" That once was heard in happier hours,
** Tho' the flowers have sunk in death, "* So when pleasure's dream is gone,
" Its memory Uves in Music's breath." T. MOORE.
XXIX. Of Physics ; or, the General Prum
perties of Mattor. 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. ...Thus, there is no intrinsic eweetness in sugar, but the quality of sweetness is in the sense of the palate.
In a violet, there is no interent colour, but the sense of colour 'called violet, is in our optic nerve and the smell of sweetness produced by the same dower, 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 nerven.--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 saine, and that all the varieties exhibited to our senses, are only so many modifications, capable of producing their respective sensible effects.
9.- A person born blind, has no proper iden 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 leaf, sees the motion of a bow on a violin, or the sticks on a drum, but has no idea of their sound. In like inanner, all food is alike, in favour, 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 sourdese, smoothness, and heal, is in us, not in the bodies which create those perceptions So, likewise, in common language, we talk of the mos tion of the sun and starsthough it is only our earth that
630. Every collection, then, of properties, capable of atiecting 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 *cad set no bounds to it, but can add millions to millions of miles in every direction.
2. Solidity is a relative idea , 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. tiba weighs as much as 92 cubic feet of cork, or as .230,000 cubic feet of hydrogen gas ; yet the platina ito self 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, Troin the consideration that every particle of matter, however small, must have an upper and an under side. The infioite 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
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 attructs 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 bis Essays on the Proximate Cuuses 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 ceniral force; and theo, invented another force
to counteract it, which nocond force bą cousidered asacting on the planets simultaneously at right angles 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 spnce 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 systein 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. Ile asserts, that all phenomena of matter are mere effects of transferred MOTION; and, that known Motions are compe tent to produce all phenomena.
Motion, he says, is that universal principle which cone fers on masses of matter the power of acting on other masses. In regard to matter, which is essentially inert, it is the source of momentum, or potentinlity, and is the animating soul of the material Universe, Space is the #tage, MATTER is the subject, and Motion is the agent, producing all phenomena. Motion appeara, says be, 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 and repel, which lead, kays Phillips, to false notions of causes, he proposes to substitute the words to accede and to disceder and for at traction, accisionand for repulsion, discission, as ex. pressing the mere acts of falling towards, and separating from. "Jostead also, gravitate or gravitation, he propones to introduce, centripetate and contripetalion.
3. Siv Richard then proceeds to shew that a stone which has been let fall to the earth is the patient of the two. fold motions of the earth, the rotatory and orbicular i and that these motions acting as forces on the stone, are competent to occasion it to fall to the earth. From this fact he deduees the following general conclusious 1-**
That every body on the earth which has hnd any new direction of force given to it, is nevertheles subjeot to the permanent influence of the pre-printing orbicular and rotatory (one in the combined lines of their dhree