Thoreau writes in his journal:
P.M.—To Walden to learn the temperature of the water . . . (Journal, 8:112-116).
Thoreau also writes to Calvin Greene:
I am glad to hear that my “Walden” has interested you—that perchance it holds some truth still as far off as Michigan. I thank you for your note. “The “Week” has so poor a publisher that it is quite uncertain whether you will find it in any shop. I am not sure but the author must turn book-sellers themselves. The price is $1.25 If you care rough for it to send me that sum by mail, (stamps will do for charge) I will forward you the copy by the same conveyance.
As for the “more” that is to come, I cannot speak definitely at present, but I trust that the mind—be it silver or lead—is not yet exhausted. At any rate, I shall be encouraged by the fact that you are interested in its yield.
Yrs respectfully
Henry D. Thoreau
