De la cécité des couleurs dans ses rapports avec les chemins de fer et la marine
A French-language medical treatise by Frithiof Holmgren, printed in Stockholm in 1877, on colour blindness as it bears on railway and naval work. Its single picture is a scientific diagram of overlapping bell-shaped curves plotted along a horizontal axis labelled with letters, numbered 2 and 3, offering a designer a clean model of graphed distribution curves for technical layouts.
