_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.
* * * * *