The Chemistry of Powder and Explosives - Sciencemadness Dot Org

ROCKETS 73
is used in whistling firecrackers, "musical salutes," "whistling
whizzers," "whistling tornados," etc. The effect of a whistle as
an accompaniment to a change in the appearance of a burning
wheel is amusing. Whistles are perhaps most effective when six
or eight of them, varying in size from the small to the large, are
fired in series, the smallest caliber and the highest pitch being
first.
Non-Picrate Whistles
Non-picrate whistles, made from a mixture of 1 part powdered
gallic acid and 3 parts potassium chlorate, are considered to be
safer than those which contain picrate. The mixture is charged
into a y2-inch case, 5/16 inch in internal diameter. The case is
loaded on a 1-inch spindle, and the finished whistle has a 1-inch
length of empty tube which is necessary for the production of he
sound. Whistles of this sort, with charges of a chlorate or
perchlorate explosive at their ends, are used in "chasers,"
"whizzers," etc., which scoot along the ground while whistling and
finally explode with a loud report,
Rockets
The principle of the rocket and the details of its design were
worked out at an early date. Improvements have been in the
methods of manufacture and in the development of more brilliant
and more spectacular devices to load in the rocket head for display
purposes. When rockets are made by hand, the present practice
is still very much like that which is indicated by Figure 23.
The paper casing is mounted on a spindle shaped to form the
long conical cavity on the surface of which the propelling charge
will start to burn. The composition is rammed into the space surrounding
the spindle by means of perforated ram rods or drifts
pounded by a mallet. The base of the rocket is no longer choked
by crimping, but is choked by a perforated plug of clay. The
clay, dried from water and moistened lightly with crankcase oil,
is pounded or pressed into place, and forms a hard and stable
mass. The tubular paper cases of rockets, gerbs, 27 etc., are now
often made by machinery, and the compositions are loaded into
them automatically or semi-automatically and pressed by hydraulic
presses.
27 Pronounced jurbs.