12. Does powder inflame instantaneously?
No; its inflammation is gradual, and progressive, and in a gun the projectile commences to move before the whole charge is ignited.
13. Why should gunpowder be grained?
In order to facilitate the transmission of the flame. When the powder is very fine, and in large and compact charges, the flame cannot penetrate it, and it burns slowly and in successive layers.
14. Which burns quickest, the small or large grained powder?
Before coming to the limit of dust, the smaller the grain, the more rapid the combustion, and the greater the bursting force of the powder.
15. What is the difference between the ignition and combustion of large and small grained powder?
With the large grained, the ignition is more rapid, but the combustion slower; with small grains, the contrary is the case.
16. Why should the grains be angular?
Because they present a greater surface to the action of the flame, and therefore burn quicker.