FOULING.
Produce of decomposed gunpowder.
The produce obtained by the decomposition of gunpowder are the gaseous and the solid. The gaseous is chiefly nitrogen and carbonic acid. The solid is sulphur and potassium, mixed with a little charcoal, but the solid produce is nearly entirely volatilized at the moment of explosion through the high temperature.
Fouling.
Fouling is occasioned by the deposition inside the barrel of the solid residue proceeding from the combustion of the powder.
Conditions of fouling depend on state of atmosphere
One of the principal of these, namely, the sulphide of Potassa, is deliquescent, or attracts water from the atmosphere. Hence, on a clear day, when the air holds little moisture, the fouling does not attain that semi-fluid state it so speedily attains in a damp day, and it is not so easily removed, and tends to accumulate inside the barrel. Fouling may also be increased or diminished, according to the quality of the powder.
Effects of Fouling.
Fouling occasions loss of power from the increased friction, and causes inaccuracy in direction and elevation, by filling the grooves, and thus preventing the proper spiral motion being imparted to the projectile.