Flashless When smokeless pow der is fired it gives a much more brilliant flash than ordinary gunpowder does and therefore when discharged after dark the position of a piece may be located by this flash. Because of the superior intensity of sunlight this flash is not ordinarily perceived by the naked eye dur ing daylight but during the Great War light screens have been devised by which to sift out this flash light from the sun light so as to locate the gun. To defeat this chemicals have been introduced into the powder by which to reduce or obscure the flash. The sodium and potas sium resinates were so used but amids and carbonates have been found still more efficient.
Progressive Smokeless With in creasing calibres and lengths of guns it be comes of increasing importance to secure a progressive rate of burning of the powder grains so that after the projectile has been moved from its seat it shall be given a con stantW increasing acceleration as it traverses the chase. The powder rains are perforated and their density varied with a view of securing this result but, since with large calibres these are insufficient, the coating of the grains with restraining substances has been resorted to, very good results having been obtained with dimethyl-diphenyl-urea which substance is for convenience styled Bibliograph.y.—Longridge, Gun Pow
der and Its Influence on un Construction> (1890) ; Moch,