Temperature coefficient of magnetic permeability within the working range
A 1915 technical paper issued by the National Bureau of Standards in Washington on how magnetic permeability of iron and steel shifts with temperature, written for physicists and electrical engineers. The plates are line graphs on ruled grids: magnetization curves labeled C-1, S-2, W-1 climbing from the origin, with hand-lettered axes, dual upper and lower scales, and percent-per-degree tick marks useful as chart furniture, diagram texture, or plain curve motifs.
