Electrical and magnetic calculations
Albert A. Atkinson's Electrical and Magnetic Calculations, published by D. Van Nostrand in New York in 1913 as a problem-solving manual for engineering students and practising electricians. The 37 figures are stark line diagrams on tinted paper: zigzag resistor coils, battery cells marked plus and minus, labelled branch circuits, and geometric load triangles with numbered legs, usable as schematic ornament or technical pattern.
