Py-roph′o-rus.
Mechanically considered, an apparatus for kindling fire.
See also electro-Phorus.
Chemically considered, a substance which takes fire when exposed to the air.
Homberg's pyrophorus depends upon the heat spontaneously developed by the association of alum, sugar, and flour.
Brande recommends a mixture of equal parts of alum and
brown sugar stirred over a fire in an iron ladle till quite dry. It is then put into an earthen or coated glass bottle, and heated red-hot so long as a flame appears at the mouth.
It is then removed, carefully stopped, and allowed to cool.
The
[
1839]
black powder which it contains becomes glowing hot when exposed to air. The experiment succeeds best in a damp state of the air, and may be accelerated by breathing upon the powder.
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Pyrophone. |
Two other recipes are given by Brande:—
Mix 3 parts of lampblack, 8 parts of carbonate of potassa, 4 parts of dried alum.
Calcine as before.
Or, 27 parts of sulphate of potassa, 15 parts of calcined lampblack.
Heat to redness in a crucible, and keep in a stoppered bottle.
Or, heat tartrate of lead red-hot in a glass tube and seal hermetically.
Break the tube and shake out the powder, which inflames spontaneously by contact with the air.
See
Cooley's “Cyclopaedia,” page 1084.
A pyrophorus for cigars is described as follows: Neutral sulphate of iron is treated with diluted nitric acid and precipitated; the resulting oxide is reduced by heat in a tube through which a current of hydrogen is passed.
This is combined with a sulphide of aluminium and potassium and a small amount of carbon.
A portion of this is placed on the end of a cigar, the breath is inhaled, and by the affinity of certain particles of the composition for oxygen the iron is heated and the cigar lighted.
