Meteorological conditions along airways
A 1927 technical report from the NASA Technical Reports Server, a government aeronautics document about weather conditions along air routes, written for pilots and airway planners. Its pictures are plain line graphs of cloud and visibility frequency by month, time of day and altitude, with wind-direction charts; a designer might take their clean axes, dashed and solid line pairs and tidy grid structure as a model for restrained scientific data graphics.
