1879. | Animal Music, its Nature and Origin. 213 
These results are as pregnant as they are simple. The perfect 
fifths, fourths, thirds and octaves have a marked predominance, 
their proportion of the whole number being respectively twenty- 
seven per cent., twenty-five per cent., twenty-six per cent. and nine 
per cent., or taken all four together, eighty-seven per cent. as 
against thirteen per cent. of the remaining five intervals. Nearly 
all the songs illustrate this pronounced harmonic character; that 
-of the song sparrow (Nos. 18-22), for example, in which the best 
intervals lie between the trills, is very good. Indeed, the very fact 
that various keys are selected in which to write bird songs is proof 
that they rest on the same basis as human music. And the 
"immense preponderance of harmonic intervals seems sufficient 
answer to whatever may be said about the difficulties and possi- 
ble inaccuracies attendant on the writing of these songs. 
There are some curious observations on the singing of birds in 
concert which seem to show that they have an “ear for music.” 
Daines Barrington (1) says that, as tested by trained ears, a dozen 
singing birds of different kinds in the same room made no dis- 
agreéable dissonance. And Mr. Augustus Fowler writes me that 
in a meadow where many red-winged black-birds are congregated, 
one may “hear their familiar notes pitched to the same key ; not 
a discordant note is uttered because the intervals are thirds, fifths, 
etc.” Ina concert of male goldfinches, when they sing for an 
hour together, “although one may pitch his tune and commence 
singing, the others following, begin their tunes on the same pitch, 
and to an unpracticed ear, or to a casual observer, their notes 
seem discordant, when they are in perfect unison. 
What few songs of other animals than birds can be gathered, 
point even more strongly in the same direction. Darwin (1, p. 
567), speaking of the Hylobates agilis, an ape allied to man, says, 
“This gibbon has an extremely loud but musical voice. Mr. 
Waterhouse states (xvi), ‘It appeared to me that in ascending and 
descending the scale, the intervals were always exactly half-tones, 
and I am sure that the highest note was the 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. Prof. Owen, who is a 
musician, confirms the foregoing stat@ment. This gibbon is not 
the only species in the genus which sings, for my son, Francis 
Darwin, attentively listened in the TE EE to H. leu~ 
