What a wonderful world this would be.
For the last homeworks in my freshman course I made a foolish mistake I keep making: I asked essay questions. The easiest questions to grade are computational: solve this by this formula. There's usually one or two ways to answer, a small set of mistakes most students fall prey to, and you can grade at a glance. Only one or two students write out space-cadet answers needing careful examination.
But essay questions ... my best students got it exactly -- compare these three alternatives, list at least one clear benefit and one drawback of each; three paragraphs suffice. How do you grade it, though, when the given answer is a cryptic half-sentence that might be something correct, but looks like a stab in the dark? Or a student rambling, mentioning so many irrelevancies it's clear they knew if they talked enough they'd say something right?
I'm glad I don't teach liberal arts courses with many essay questions; but, then, if I did I'd have an idea how to grade these cases. Much easier, as a grad student, was grading computer labs with computational questions interspersed with very tightly focused short-answer questions; one could grade on correctness and even on grammar and spelling (and you haven't heard whining until you've heard engineering majors insisting they don't have to know the difference between it's and its; happily, my professors always backed me up).
Worse, of course, is I asked easy questions. If anything other than the first question is a softball, many students freeze up, either turning it into a difficult question or skipping it entirely. It would be so much less work if everyone would just answer right instead.
Trivia: Melpomene, asteroid number 18, discovered 24 June 1852 by J. R. Hind at London, was the first body in the solar system not given a zodiacal symbol. Source: Dictionary of Minor Planet Names, Lutz D. Schmadel.
Currently Reading: `T. E. Lawrence': In Arabia and After, Basil H. Liddell-Hart.