Читать книгу A New Catalogue of Vulgar Errors - Fovargue Stephen - Страница 6

That the Tone of a Violin is to be brought out, by laying on like a Blacksmith.

Before we can convince such of our Readers as have no Knowledge in that Part of Pneumatics which is called Harmonics, of this Mistake, it will be necessary just to give a short Account of the Cause of Sound in stringed Instruments.

In the first Place, all Sound proceeds from Undulations in the Air, which is an elastic Fluid; and with regard to these Undulations, is much of the same Nature as Water, which is another Fluid, but differs from Air in many Respects. Now when a Person throws a Stone into Water, these Undulations or Waves are raised in the Fluid for some Distance, by the Force and Action of one Wave upon another. This is the Case with regard to Sound; only the Air being an elastic Fluid, these Undulations are more quick and brisk in their Motions than in Water. So much for Sound itself. Now for the Cause of this Sound, or of these Undulations.

These Undulations are caused by the Vibration of some elastic Body, which is put into Motion by a Stroke of another Body against it. It must be an elastic Body (take notice) for upon that Word depends the Truth of what is going to be alledged. To convince the Reader of the Truth of this, he has nothing to do but to take a Rolling Pin, and strike it against a Pound of Butter, and he will find very little or no Sound at all, because Butter has very little Elasticity or Spring in it; but if he strikes the aforesaid Implement against the Table, he will find Sound enough, because most Tables are made of Wood, which is a very elastic Body. If there is no Butter in the House, Wax will do as well or better, for it will prove that a Body may be hard without being elastic, and which will be very much to the Purpose. It will be necessary, before we can get any further, to explain what Vibration is, a Word very commonly made Use of among Musical Men, tho' but little understood.

To be as short as possible; a Piece of Lead hung upon the End of a String, which moves backwards and forwards of itself after being first put into Motion, is called a Pendulum, and that Motion backwards and forwards is called its Vibration; it is upon this Principle that elastic Bodies are the Cause of Sound. It will be best illustrated in a Musical Instrument, besides that is the Point in Hand; and to be more to the Point still, we will suppose it a Violin, though any other stringed Instrument would answer the same End.

Here we have four Strings stretched out upon a Bridge, or thin Piece of Wood, which communicates to the Belly of the Instrument, from which Belly the greatest Part of the Tone proceeds. Now a String drawn tight at both Ends, when it is struck, will have a Vibration or tremulous Motion, which Vibration, or tremulous Motion, acts upon the same Principle as a Pendulum does in a Cycloid, or, to speak as plain as possible, as a Pendulum does when it is put into it's proper Motion.

It is upon this Principle of Vibration then, or tremulous Motion, that the String of a Violin, being moved by the Bow, is to act: The String immediately communicates it's tremulous Motion to the Bridge, and the Bridge to the Belly of the Instrument, which Belly being made of a very elastic Wood, by it's Vibration and free Motion, acts upon the Air in the Manner abovementioned.

As it is the great Elasticity of the Wood which is to cause the Tone, it ought to have as little Confinement in it's Vibrations as is possible; the Weight of the Strings must indeed press against it, otherwise they could not communicate their Motion to it. We should therefore be careful not to over-string the Instrument, since it so plainly contradicts the Principles of Pneumatics.

It is easy to hear when an Instrument is over-strung; and sometimes an Octave in a Harpsichord, by it's additional Number of Strings, shall render the Tone of the Instrument so dead, that, though it gives a Sprightliness peculiar to an Octave, yet it sometimes hardly compensates for the Loss of Tone which it causes in the Unisons, by it's too great Pressure upon the Belly of the Instrument.

And yet notwithstanding all this, what is more common than to see a Performer, with his Waistcoat unbuttoned, laying Strokes on a Violin, heavy enough to fell an Ox.

The Truth is, managing the Bow is slight, and we must make Use of Art more than Strength in our Performance: moreover, it is an Art which cannot be wrote down upon Paper, nor explained in Words, but must be learned by the Example and Direction of some assiduous Master. However what has been said may serve to shew, from Philosophical Principles, the Error of leaning too hard upon the Instrument, which was the Thing intended to be done.