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Oscillation

Oscillation
Oscillation
Oscillation

Keely
"Oscillation is a rhythmically recurring translatory movement." [Keely]

OSCILLATION. - The swing of a pendulum, and its return. [Scientific Basis and Build of Music, page 25]

Not the same as vibration. [see Vibration]

Ramsay
"In the laws of quantities and motions there are three primary ratios from which the musical system of vibrations is developed. Pendulums, from the slowness and continuance of their motions, are well adapted to give an ocular demonstration of the relative motions of each of these three primary ratios when compared and combined with the unity and with each other. The numbers 2 and 4 express the first condition in the first ratio; as, in falling bodies, when the times are 2 the distances are 4. In the case of two pendulums, when the length of the one is one fourth part of the other the motions are 1:2; and when two is counted for the upper one, the oscillations of these two pendulums will meet at one. The numbers 3 and 9 express the first condition of the second ratio; as, in falling bodies, when the times are 3 the distances are 9. In the case of two pendulums, when the length of the one is the ninth part of the other, the motions are 1:3; and when three is counted for the upper one, the oscillations of these two pendulums will meet at one. The numbers 5 and 25 express the first condition in the third ratio; as, in falling bodies, when the times are 5 the distances are 25. In the case of two pendulums, when the length of the one is twenty-fifth part of the other, the motions are 1:5; and when five is counted for the upper one, the v of these two pendulums will meet at one. In the system of motions in pendulums, the three primary ratios indicated in the foregoing paragraph, namely, 2:4, 3:9, and 5:25, are compared and combined with three different units. In their comparison, 1 is the unit of quantities, that is lengths, and 1 is the unit of motions. The numbers 1/4, 1/9, and 1/25, when taken together with 1 as unity, express the first comparison and combination of quantities; and the numbers 2, 3, and 5, taken together with 1 as unity, express the first comparison and combination of motions." [Scientific Basis and Build of Music, page 15]

"The numbers which express the motions of these twenty-five quantities have among themselves nineteen different ratios, or rates of meeting; and when these ratios are represented by the oscillations of twenty-five pendulums, at the number of 64 for the highest one, they will all have finished their periods, and meet at one for a new series. This is an illustration, in the low silence of pendulum-oscillations, of what constitutes the System of musical vibration in the much higher region of vibrating strings and other elastic bodies, and determines the number of undeveloped sounds which form the harmonious halo of one sound, more or less faintly heard, or altogether eluding our dull mortal ears; and which determines the number of sounds which, when developed, constitute the System of musical sounds." [Scientific Basis and Build of Music, page 16]

"Things are not always what they seem. Common sense, so very valuable in every-day life, goes but a very little way in science. Common sense could not have told that, when a uniform body is suspended at one end and oscillated as a pendulum, the oscillations would be the same if suspended at one-third from the end. Much less could common sense have told that suspension at a point between these two points, namely, at two-thirds of this one-third from the end, would give the highest rate of speed of oscillation of which the body is capable, a point which we shall call the center of Velocity." [Scientific Basis and Build of Music, page 18]

"the other, like as we also reckon the vibrations of a pendulum." Holden adds that Dr. Smith, in his Harmonics, reckons the complete vibration to be double of this. Lees, in his Acoustics, says- "The travel of a vibrating elastic body from one extreme to the opposite and back again is called a vibration. Continental writers define a vibration to be the travel of a vibrating body from one extreme position to the opposite. This corresponds to our definition of the oscillation of a pendulum." [Scientific Basis and Build of Music, page 23]

"If we take a pendulum which goes from side to side 60 times in a minute, and another which goes from side to side 120 times in a minute, these two pendulums while oscillating will come to their first position 30 times during the minute. Now, if an oscillation is to be considered a natural operation, like the revolution of a wheel, or that of a planet in its orbit, which is completed when it returns to the place where the revolution began, then the pendulum's oscillation is not completed till it returns to the place of starting; and thus defined the oscillations of these two pendulums in the minute are not 60 and 120, but 30 and 60; 30 is the unit of measure in this case - 30 is the 1, and 60 is the 2; and this would establish the ratio of 1 to 2 in these two pendulums. And what is true in the ratio of 1 to 2 is true also of every other ratio, in this respect. This is a natural basis to work on, and defines the oscillation of a pendulum to be its excursion from extreme to extreme and back." [Scientific Basis and Build of Music, page 25]

pendulum where fourth the length is double the oscillations. A third condition in this order is in springs or reeds where half the length is four times the vibrations. If we take a piece of straight wire and make it oscillate as a pendulum, one-fourth will give double the oscillations; if we fix it at one end, and make it vibrate as a spring, half the length will give four times the vibrations; if we fix it at both ends, and make it vibrate as a musical string, half the length will produce double the number of vibrations per second. [Scientific Basis and Build of Music, page 80]

This elongated body suspended at the end, or at one-third from the end, the oscillations are the same. The one-third above the point of suspension so balances the two-thirds below that the oscillations are performed in the same time for both suspensions. When it is [Scientific Basis and Build of Music, page 92]


OSCILLATION AND VIBRATION.

Fig. 1 - The pendulums in this illustration are suspended from points determined by the division of the Octave into Commas; the comma-measured chords of the Major key being S, 9, 8, 9, 5; T, 9, 8, 5, 9; D, 8, 9, 5, 9. The pendulums suspended from these points are tuned, as to length, to swing the mathematical ratios of the Diatonic scale. The longest pendulum is F, the chords being properly arranged with the subdominant, tonic, and dominant, the lowest, center, and upper chords respectively. Although in "Nature's Grand Fugue" there are 25 pendulums engaged, as will be seen by reference to it, yet for the area of a single key 13 pendulums, as here set forth, are all that are required. It will not fail to be observed that thus arranged, according to the law of the genesis of the scale, they form a beautiful curve, probably the curve of a falling projectile. It is an exceedingly interesting sight to watch the unfailing coincidences of the pendulums perfectly tuned, when started in pairs such as F4, A5, and C6; or started all together and seen in their manifold manner of working. The eye is then treated to a sight, in this solemn silent harp, of the order in which the vibrations of sounding instruments play their sweet coincidences on the drum of the delighted ear; and these two "art senses," the eye and the ear, keep good company. Fig. 2 is an illustration of the correct definition of a Pendulum Oscillation, as defined in this work. In watching the swinging pendulums, it will be observed that the coincidences [Scientific Basis and Build of Music, page 104]

are always when they have returned to the side from which they were started. The Pendulographer, also, when writing the beautiful pictures which the musical ratios make when a pen is placed under the control of the pendulums, always finds his figure to begin again when the pendulums have finished their period, and have come for a fresh start to the side from which the period began. This confirms our author's definition of an oscillation of a pendulum. Fig. 3 is an illustration of the correct definition of a Musical Vibration, as also given in this work. Although the definition of an oscillation is not identical with that of a vibration, yet on account of their movement in the same ratios the one can be employed in illustration of the other as we have here done. Fig. 4 is a uniform rod suspended from the end as a pendulum; it will oscillate, of course, at a certain speed according to its length. In such a pendulum there are three centers related in an interesting way to the subject of Music in its three chords - subdominant, tonic, and dominant, which roots are F, C, and G. The center of gravity in the middle of the rod at 2, suspended at which the rod has no motion, corresponds to F, the root of the subdominant, in which there is the maximum of musical gravity. The center of oscillation at 3, which is one-third of the length of the rod from the end, is like the root of the tonic whose number is 3 in the genesis of the scale from F1. In this point of suspension the oscillations are the same as when suspended from the end at 1. The point at 9 is at a ninth from the center of oscillation. Our author discovered that, if suspended at this point, the pendulum had its highest rate of speed. Approaching the end, or approaching the center of oscillation from this point, the rate of speed decreases. Exactly at one-ninth from the center of oscillation, or two-ninths from the end, is this center of velocity, as Ramsay designated it; and it corresponds in some sort also to the root of the dominant G, which is 9 in the genesis of the scale from F1; its rate of vibration is nine times that of F1. The dominant chord is the one in which is the maximum of levity and motion in music. [Scientific Basis and Build of Music, page 105]

When 25 pendulums are arranged and oscillated to represent the different musical ratios in their natural marshalling, they will all meet at 1 when 64 of the highest is counted. This plate is intended to show that there are two kinds of meeting and passing of the pendulums in swinging out these various ratios. In the ratio of 8:9 the divergence goes on increasing from the beginning to the middle of the period, and then the motion is reversed, and the difference decreases until they meet to begin a new period. This may be called the differential way. In the ratio of 45:64 there is an example of what may be called the proximate way. In this kind of oscillations meet and pass very near to each other at certain points during the period. In 45:64 there are 18 proximate meetings; and then they exactly meet at one for the new start. This last of the ratios, the one which finished the system, is just as if we had gone back to the beginning and taken two of the simplest ratios, [Scientific Basis and Build of Music, page 105]

When Ramsay gave a course of lectures in Glasgow, setting forth "What constitutes the Science of Music," his lecture-room was hung round with great diagrams illustrating in various ways his findings; an ocular demonstration was also given of the system of musical vibrations by his favorite illustration, the oscillations of the Silent Harp of Pendulums. A celebrated teacher of music in the city came to Mr. Ramsay's opening lecture, and at the close remained to examine the diagrams, and question the lecturer, especially on his extension of the harmonics to six octaves. Having seen and heard, this teacher went and shortly after published it without any acknowledgment of the true authorship; and it was afterwards republished in some of the Sol-Fa publications, the true source unconfessed; but our plagarist stopped short at C, the top of the tonic, instead of going on to F, the sixth octave of the root of all; the effect of this was to destroy the unity of the great chord. The 22 notes instead of 25, at which this teacher stopped, allowed him, indeed, to show the natural birthplace of B, which Ramsay had pointed, but it beheaded the great complex chord and destroyed its unity. If C, the root of the tonic, be made the highest note, having quite a different character from F, it pronounces its character, and mars the unity of the great chord. Similar diversity of effect is produced by cutting off only two notes of the 25 and stopping short at D, the top of the dominant; and also, though in a weaker degree, by cutting off only one note of the 25 and stopping at E, the middle of the tonic; this, too, disturbs the unity of the fundamental sound. [Scientific Basis and Build of Music, page 111]

See Also


Rhythmic Balanced Interchange
Ramsay - The New Way of Reckoning a Pendulum Oscillation
Rotation and Revolution are Reciprocals
Sine Wave
Vibration
Vortex
Wave
Wave Field
7.2 - Rhythmic Balanced Interchange
8.2 - Oscillation versus Vibration

Created by Dale Pond. Last Modification: Monday December 28, 2020 03:58:49 MST by Dale Pond.