398 
I]. ComprticaTion oF Sounds IN THE 
Tones or Musicau Instruments, — 
But it may be stated, that a similar dif- 
ference (in degree at least) exists in 
what the Italians call the voices of in- 
struments. This is readily granted. 
“ A musician can single out from a 
number of instruments of the same 
kind, one that is familiar to him, merely 
by hearing them separately,” says Mr. 
Gough; and he further proceeds to 
state, with equal accuracy, that “a 
flute will play in concert with a violin, 
yet their notes [tones] considered apart, 
are as distinct as any two things can 
be.” This acute philosopher has stated 
these very circumstances, as part of his 
data, in an argument essentially the 
same with that of the present lecture.* 
» © The mechanism of sonorous bodies, 
which is capable of producing effects so 
diversified to sense, though so slightly dis- 
criminated in nature, depends on a prin- 
ciple that is easily understood. It is purely 
this: if a vibratory motion be imparted to 
any one of a system of eiastic bodies that 
are connected together, the same is imme- 
diately communicated, in a less degree, to 
every body of the system, whose time of 
vibrating agrees nearly with that of the 
body first put in motion. Yor instance, let 
two equal strings be stretched on a frame, 
with degrees of tension that are nearly 
oer but not perfectly so; then if either 
of them be made to vibrate, the other will 
accompany it in so distinct a manner, that 
their joint tone is easily known from the 
sound of either of them taken singly. This 
plain experiment reconciles the theory to 
common obseryation, as it points out the 
method followed by nature, in compounding 
ordinary tones from elementary sounds ; 
for not. only all musical instruments, but 
also the vocal organs of men and animals 
are complex machines, consisting of one 
particular part, intended for the production 
of sound, which is connected with many 
others necessary to render the whole per- 
fect. Now, it is evident, that such of these 
secondary members as are nearly in unison 
with the principal, must participate of all 
its motions, forming, in conjunction with 
it, a number of simple sounds, all of them 
contained in a narrow interval, which is 
terminated by one of the number that is 
graver, and one that is acuter than the rest. 
The relative affections of these combinations, 
or the mutual ratios of their constituent im- 
perfect unisons, may’ be varied indefinitely, 
even in instruments or vocal organs of the 
same description, from the numberless slight 
variations that take place, of necessity, in the 
elasticity and tension of their respective similar 
parts; the obvious consequence of which 
is, that the cycles of their joint beats or 
pulses will be diversified in a manner 
The Anatomy of Speech. 
[June I, 
The fact is, that the tones of musical 
instruments themselves are not so sim- 
ple and uncompounded as is generally 
supposed. It is not alone upon the 
length and bore of the pipe, and the 
exact distances of the stops, or upon the 
length, tension, thickness and texture 
of the chords, or the particular dispo- 
sition of the keys, that the character- 
istic voice of an instrument depends. 
The form and texture of the body of 
the instrument, even to the minutest 
differences, have their importance: the 
fibres of these (in the violin or piano- 
forte, for example) must vibrate, respon- 
dent to the original impulse of the 
string ; in other words, the “ quick suc- 
cession of aé@rial pulses produced by 
the original vibration, puts them, also, 
into tremulous motion,’ which they 
immediately communicate to the por- 
tion of air in contact with them, and 
which, spreading through the same 
space, and co-existing with the original 
pulses, produce a consentaneous aggre- 
gate of vibrations, as complicated as the’ 
number and circumstances of the fibres 
among which. the vibrations are ex- 
cited. That this isthe fact, may easily 
be demonstrated by the experiment of 
striking a given note on the piano- 
forte, and immediately stopping not 
only that particular string, but all the 
strings that are partly in unison with 
it; when, notwithstanding that the 
wires are completely silenced, a mur- 
muring sound, preserving the charac- 
teristic tone of the instrument, will, for 
some time, continue to be heard.’ The 
fact might be still further illustrated by 
the simple experiment of stretching the 
chords of an instrument upon a mere 
frame, without any resounding surface 
beneath, or in contact with them ; when 
it would soon be evident, whether it be 
the string alone, or whatever else it be 
that constitutes the characteristic voice 
of the instrument. 
This murmuring sound, I conceive, 
must be admitted as the result of what 
may be called the secondary vibrations 
of 
equally unlimited. Now it is very well 
known, that the different sensations pro- 
duced by several musical intervals, arise 
from the comparative properties of their 
respective cycles: but what is proved of 
larger intervals will hold good in respect to. 
smaller; and is equally applicable to their 
effects on the ear, which are therefore 
shewn to be susceptible of unlimited modi- 
fications in the common course of. things.’” 
—Gough on Var. Voi., p. T—9. 
