653 
The THEORY of COMPOUND SOUNDS. 
BY MR. JOHN GOUGH. 
_COMMUNICATED BY DR, HOLME, _ 
Dr. Smith, author of the work on Harmo- 
nics, takes for granted in his theory of com- 
pound sounds, that the pulses which proceed at 
the same time from a number of sounding bodies, 
do not clash, or obstruct one another, in their 
passage through the air. According to this hy- 
pothesis, each set, of any number of cotempo- 
rary sets of pulses, strikes the ear without being 
confounded with the rest; in’ consequence of 
which, any number of sounds may be distinctly 
perceived at the same time. On this supposition, 
a compound sound is a sensation rendered vari- 
able by the irregular manner in which the pulses 
of the constituent sounds succeed to one another. 
For, if the intervals of time between two succes- 
sive pulses of one of the constituent sounds be 
not equal to the same intervals belonging to the 
sound or sounds which accompany it, the secon- 
dary intervals, or small parts of time separating the 
pulses which fall in succession on the ear, will 
vary in magnitude ; in the same manner that the 
distances between the figures upon the face of a 
ri 
