Read it through once

One day we were approaching New Madrid, bound down and heavily laden. Brown was at one side of the wheel, steering; I was at the other, standing by to 'pull down' or 'shove up.' He cast a furtive glance at me every now and then. I had long ago learned what that meant; viz., he was trying to invent a trap for me. I wondered what shape it was going to take. By and by he stepped back from the wheel and said in his usual snarly way--