viz., "However delightful any scientific pursuit may be, yet, if it should
be wholly unapplied, it is of no more use than building castles in the
air." Would not your hearers infer from this that the practical use of
each scientific discovery ought to be immediate and obvious to make it
worthy of admiration? What a beautiful instance chloroform is of a
discovery made from purely scientific researches, afterwards coming almost
by chance into practical use! For myself I would, however, take higher
ground, for I believe there exists, and I feel within me, an instinct for
truth, or knowledge or discovery, of something of the same nature as the
instinct of virtue, and that our having such an instinct is reason enough
for scientific researches without any practical results ever ensuing from
them. You will wonder what makes me run on so, but I have been working
very hard for the last eighteen months on the anatomy, etc., of the
Cirripedia (on which I shall publish a monograph), and some of my friends
laugh at me, and I fear the study of the Cirripedia will ever remain
"wholly unapplied," and yet I feel that such study is better than castle-
building.


LETTER 27. TO J.D. HOOKER,
at Dr. Falconer's, Botanic Garden, Calcutta.
Down, May 10th, 1848.

I was indeed delighted to see your handwriting; but I felt almost sorry
when I beheld how long a letter you had written. I know that you are
indomitable in work, but remember how precious your time is, and do not
waste it on your friends, however much pleasure you may give them. Such a
letter would have cost me half-a-day's work. How capitally you seem going
on! I do envy you the sight of all the glorious vegetation. I am much
pleased and surprised that you have been able to observe so much in the