Read it through once

The pilot who deposited that blank in the Cairo box (after adding to it the details of every crossing all the way down from St. Louis) took out and read half a dozen fresh reports (from upward-bound steamers) concerning the river between Cairo and Memphis, posted himself thoroughly, returned them to the box, and went back aboard his boat again so armed against accident that he could not possibly get his boat into trouble without bringing the most ingenious carelessness to his aid.