The Chemistry of Powder and Explosives - Sciencemadness Dot Org

WHEELS 91
denly with a terrifying roar at the moment of its maximum
splendor. If loaded at the hydraulic press with a tapered spindle
(as is necessary), it finishes its burning wifh a fountain which
grows smaller and smaller and finally fades out entirely.
Wheels
Driving tubes or drivers, attached to the periphery of a wheel
or to the sides of a square or hexagon of wood which is pivoted
FIGURE 31. Matching Display Wheels (Courtesy National Fireworks
Company and the Boston Globe.)
at its center, by shooting out jets of fire, cause the device to
rotate and to produce various ornamental effects according to the
compositions with which they are loaded. When the fire reaches
the bottom of one driver, it is carried by quickmatch to the top
of the next. Drivers are loaded in the same manner as gerbs, the
compositions being varied slightly according to the size as is
done with rockets. A gross of the 1-ounce and 2-ounce sizes in
present American practice is loaded at one time by the hydraulic
prcsri. Typical wheel turning compositions (Allen F. Clark) for