t has
proved one of the most difficult problems of the practical astronomer
to obtain an achromatic telescope, so an achromatic eye, one of the
most needed, is also one of the rarest instruments of criticism.

She was very susceptible to pleasurable stimulus, took delight in
details of form, color, and sound. Her fancy and imagination were
easily stimulated to genial activity, and she erroneously thanked the
artist for the pleasing emotions and thoughts that rose in her mind.
So that, though capable of it, she did not always bring that highest
tribunal to a work of art, namely, the calm presence of greatness,
which only greatness in the object can satisfy. Yet the opinion was
often well worth hearing on its own account, though it might be wide
of the mark as criticism. Sometimes, too, she certainly brought to
beautiful objects a fresh and appreciating love; and her written
notes, especially on sculpture, I found always original and
interesting. Here are some notes on the Athenaeum Gallery of Sculpture,
in August, 1840, which she sent me in manuscript:--

'Here are many objects worth study. There is Thorwaldsen's
Byron. This is the truly beautiful, the ideal Byron. This head
is quite free from the got-up, caricatured air of disdain,
which disfigures most likenesses of him, as it did himself
in real life; yet sultry, stern, all-craving, all-commanding.
Even the heavy style of the hair, too closely curled for
grace, is favorable to the expression of concentrated life.
While looking at this head, you learn to account for the grand
failure in the scheme of his existence. The line of the cheek
and chin are here, as usual, of unrivalled beauty.

'The bust of Napoleon is here also, and will naturally be
named, in connection with that of Byron, since the one in
letters, the other in arms, represented more fully than any
other the tendency of their time; more than any other gave it
a chance for reaction. There was another point of resemblance
in the external being of the two, perfectly corresponding with
that of the internal, a sense of which peculiarity drew on
Byron some ridicule. I mean that it was the intention of
nature, that neither should ever grow fat, but remain a
Cassius in the commonwealth. And both these heads are taken
while they were at an early age, and so thin as to be still
beautiful. This head of Napoleon is of a stern be