1. The explosion limits are here numbered in order of increasing pressure. See also refs. 3 and 4 where the same convention is used.
2. Lewis and von Elbe, "Combustion, Flames and Explosions of Gases", 39 (Cambridge, 1938).
3. Lewis and von Elbe, J. Chem. Phys., 10, 376 (1942).
4. Willbourn and Hinshelwood, Proc. Roy. Soc., A, 185, 353 (1946).
5. For elaboration of this, see Dainton, Trans. Farad. Soc., 38, 227 (1942).