The smouldering of beech and deal sawdusts in still
air has been investisated. The dusts were fanned into
small trains and the linear rate of propagation of
smouldering measured. This rate was slow and was not
materially affected by variations in packing density,
particle size, moisture content or size of train provided
that the latter is greater than a certain critical value,
depending chiefly upon the particle size of the sawdust.
Practical applications of these results are discussed.