The actions of both hands are singularly sweet. The right is one of the
loveliest things I ever saw done in painting. She is keeping down one
note only, with her third finger, seen under the raised fourth: the
thumb, just passing under; all the curves of the fingers exquisite, and
the pale light and shade of the rosy flesh relieved against the ivory
white and brown of the notes. Only the thumb and end of the forefinger
are seen of the left hand, but they indicate enough its light pressure
on the bellows. Fortunately, all these portions of the fresco are
absolutely intact.

Underneath, Tubal-Cain. Not Jubal, as you would expect. Jubal is the
inventor of musical instruments. Tubal-Cain, thought the old
Florentines, invented harmony. They, the best smiths in the world, knew
the differences in tones of hammer strokes on anvil. Curiously enough,
the only piece of true part-singing, done beautifully and joyfully,
which I have heard this year in Italy, (being south of Alps exactly six
months, and ranging from Genoa to Palermo) was out of a busy smithy at
Perugia. Of bestial howling, and entirely frantic vomiting up of
hopelessly damned souls through their still carnal throats, I have
heard more than, please God, I will ever endure the hearing of again in
one of His summers.

You think Tubal-Cain very ugly? Yes. Much like a shaggy baboon: not
accidentally, but with most scientific understanding of baboon
character. Men must have looked like that, before they had invented
harmony, or felt that one note differed from another, says, and knows
Simon Memmi. Darwinism, like all widely popular and widely mischievous
fallacies, has many a curious gleam and grain of truth in its tissue.