Some effects of argon and helium upon explosions of carbon monoxide and oxygen
This is a 1937 technical report from the NASA Technical Reports Server, an experimental study of carbon monoxide and oxygen explosions diluted with argon or helium, written for combustion researchers. The three pictures are line graphs of flame radius, flame speed and a speed difference plotted against the mole fraction of inert gas, with data points marked by circles and crosses. A designer might take from them only the clean grid-and-curve plotting style, with its sparse dotted series and labelled curves.
