Astonishing things can be done with the human memory if you will devote it faithfully to one particular line of business.
At the time that wages soared so high on the Missouri River, my chief, Mr.Bixby, went up there and learned more than a thousand miles of that stream with an ease and rapidity that were astonishing.

When he had seen each division once in the daytime and once at night, his education was so nearly complete that he took out a 'daylight' license; a few trips later he took out a full license, and went to piloting day and night--and he ranked A 1, too.
Mr.Bixby placed me as steersman for a while under a pilot whose feats of memory were a constant marvel to me.

However, his memory was born in him, I think, not built.

For instance, somebody would mention a name.
Instantly Mr.Brown would break in-- 'Oh, I knew HIM.

Sallow-faced, red-headed fellow, with a little scar on the side of his throat, like a splinter under the flesh.