> I also succeeded in passing the preliminary examination for the Army while still almost at the bottom of the school. This examination seemed to have called forth a very special effort on my part, for many boys far above me in the school failed in it. I also had a piece of good luck. We knew that among other questions we should be asked to draw from memory a map of some country or other. The night before by way of final preparation I put the names of all the maps in the atlas into a hat and drew out New Zealand. I applied my good memory to the geography of that Dominion. Sure enough the first question in the paper was: ‘Draw a map of New Zealand.’

I can well imagine that a military officer may need to have that knowledge at hand faster than consulting a map. ("I am the very model of a modern major general!" and all.) For upper-class U.S. Harvard students, trade knowledge may be more important, thought that doesn't explain needing to know the source of the Amazon.