Primary cells as source of power
A 1913 engineering thesis by Jesse Kramer at the University of Illinois, testing primary cells—chromic acid and sodium dichromate—as power sources for an instructor-supervised electrical course. Hand-lettered curves drawn in ink on printed yellow-green graph paper plot voltage, watts, and amperes against time, with faint blue grids, sparse axis labels, and inked signatures useful as ready-made chart textures.
