Henslow," by Leonard Jenyns, page 150.), which I like very much.
The anecdote about Whewell and the tides I had utterly forgotten; I believe it is near enough to the truth.

I rather demur to one sentence of yours--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.