Jo's Boys by Louisa May Alcott

'I don't expect to hear from Emil yet, and Nat writes regularly, but where is Dan? Only two or three postals since he went. Such an energetic fellow as he is could buy up all the farms in Kansas by this time,' said Mrs Jo one morning when the mail came in and no card or envelope bore Dan's dashing hand.

'He never writes often, you know, but does his work and then comes home. Months and years seem to mean little to him, and he is probably prospecting in the wilderness, forgetful of time,' answered Mr Bhaer, deep in one of Nat's long letters from Leipzig.