1 Paine indicated that this sentence was from one of Mark Twain’s Aurora letters to Orion, which were “full of such admonition” (MTB, 1:198). The sentence is probably from a letter, now lost, that preceded the next two letters, which contain very similar “calls” upon Orion and mention tunnels on two Aurora claims: the Horatio and Derby, and the Red Bird. Since it is not known exactly when between 2 and 13 April Clemens arrived in Aurora, the assigned date remains conjectural.