exact octave to the lowest. The quality of the notes is very musical;
and I do not doubt that a good violinist would be able to give a
correct idea of the gibbon s composition, excepting as regards its
loudness. Mr. Waterhouse then gives the notes. Professor Owen, who is
a musician, confirms the foregoing statement, and remarks, though
erroneously, that this gibbon alone of brute mammals may be said to
sing. It appears to be much excited after its performance.
Unfortunately, its habits have never been closely observed in a state
of nature; but from the analogy of other animals, it is probable that
it uses its musical powers more especially during the season of
courtship.
This gibbon is not the only species in the genus which sings, for my
son, Francis Darwin, attentively listened in the Zoological Gardens to
H. leuciscus whilst singing a cadence of three notes, in true musical
intervals and with a clear musical tone. It is a more surprising fact
that certain rodents utter musical sounds. Singing mice have often been
mentioned and exhibited, but imposture has commonly been suspected. We
have, however, at last a clear account by a well-known observer, the
Rev. S. Lockwood (31. The American Naturalist, 1871, p. 761.), of the
musical powers of an American species, the Hesperomys cognatus,
belonging to a genus distinct from that of the English mouse. This
little animal was kept in confinement, and the performance was
repeatedly heard. In one of the two chief songs, the last bar would
frequently be prolonged to two or three; and she would sometimes change
from C sharp and D, to C natural and D, then warble on these two notes
awhile, and wind up with a quick chirp on C sharp and D. The
distinctness between the semitones was very marked, and easily
appreciable to a good ear. Mr. Lockwood gives both songs in musical
notation; and adds that though this little mouse had no ear for time,
yet she would keep to the key of B (two flats) and strictly in a major
key. ... Her soft clear voice falls an octave with all the precision
possible; then at the wind up, it rises again into a very quick trill
on C sharp and D.
A critic has asked how the ears of man, and he ought to have added of
other animals, could have been adapted by selection so as to
distinguish musical notes. But this question shews some confusion on
the subject; a noise is the sensation resulting from the co-existence
of several aerial simple vibrations of various periods, each of which
591