The Chemistry of Powder and Explosives - Sciencemadness Dot Org

PHARAOH'S SERPENTS 119
Wire Dips and Colored Fire Sticks
These devices arc made in the same way as sparklers, by dipping
wires or twisted narrow strips of iron or thin sticks of wood,
and generally burn with a tranquil flame except for the sparks
that come from the burning of the iron wire or strip. Several
typical compositions are listed. Alcohol is used for applying the
Potassium chlorate ..
Potassium percklorate
Strontium nitrate
Barium chlorate
Fine aluminum powder
Coarse aluminum powder
Shellac
Red gum
Dextrin
5
1
Red
2
6
6
1
•
3
16
,
4
3
Green
16
24
3
White
compositions which contain shellac; water, for applying the
others which contain dextrin.
Pharaoh's Serpents 03
Wohler in 1821 first reported the remarkable property of mercurous
thiocyanate that it swells up when it is heated, "winding
out from itself at the same time worm-like processes, to many
times its former bulk, of a very light material of the color of
graphite, with the evolution of carbon disulfide, nitrogen, and
mercury." Mercuric thiocyanate, which gives better snakes than
the mercurous compound, came early into use for this purpose in
pyrotechnic toys. When a heap or pellet of either of these compounds
is set on fire, it burns with an inconspicuous blue flame,
producing sulfur dioxide and mercury vapor. The resulting pale
brown or pale gray snake, if broken, ;s found to be much darker
in the interior, and evidently consists of paracyanogen and mercuric
sulfide, the mercury having been burned and vaporized
from the outer layer.
Mercuric thiocyanate is prepared by adding a solution of
53 Cf. Davis, article entitled "Pyrotechnic Snakes," in J. Chem Education,
17, 268-270 (1940)
10
7
3