One of my professors, Yuval Grossman, was talking about the zoology of particle physics in class the other day. Trying to get us to remember such trivia as the mass of the B meson, he noted that it's easier to remember two things than it is to remember one - and as it happens, the mass of the B meson is about 5280 MeV, which is also the length of a mile in feet (an equally obscure piece of trivia, if you ask me). This reminded of one of my first calculus classes back home where another professor (Mikhail Sodin) chided us for not knowing the value of e, 2.71828. This is easy to remember, he said because 1828 is the year Lev Tolstoy was born. Then again, when I came to write this post, I could neither remember e, nor Tolstoy's year of birth - or even that it was Tolstoy, rather than Dostoevsky or some other Russian author. So perhaps two things are not easier to remember than one after all.