BY MARK TWAIN. Extending the Blessings of Civilization to our Brother who Sits in Darkness has been a good trade and has paid well, on the whole; and there is money in it yet, if carefully worked—but not enough, in my judgment, to make any considerable risk advisable. The People that Sit in Darkness are getting to be too scarce—too scarce and too shy. And such darkness as is now left is really of but an indifferent quality, and not dark enough for the game. The most of those People that Sit in D