Marginal Math

This semester I've been teaching a large Shakespeare lecture course in one of the precious few auditorium classrooms on campus. The class that meets immediately before ours couldn't be more different: an Engineering course called "Dynamics" which is described with phrases I haven't thought about in years (vector calculus? multiparticle systems?)  The instructor of that course always leaves cryptic formulas on the chalkboard, which, of course, we often promptly transform into a symbolic trajectory of the play we happen to be reading (we can plot Hamlet's trajectory on this axis; Ophelia, unfortunately, remains static...). More to my immediate purpose, though, it's reminded me of the intersection of early modern reading practices and math problems -- or, to put it more prosaically, the penchant of readers to scribble math problems in the  margins of their books, utilizing the valuable real estate of the page as a piece of proverbial scrap paper. Here are three examples I've come across in our Special Collections library.