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inflammable body whatever, a pyrophorus may be made of all 
such substances as contain vitriolic acid combined either with 
earth, or with an alkaline salt, or with a metallic substance. 
Little improvement in the composition of the pyrophorus was 
introduced until the time of Gray Lussac, with whose name all 
moderns are familiar. Gray Lussac modified the process by 
placing lamp-black, instead of the animal matters named, in 
the retort. A little further on, sulphate of magnesia was sub- 
stituted by the same chemist for alum; and at last the follow- 
ing’ formula was given as the best for an active pyrophorus : 
lamp-black, 15 parts; sulphate of potassa, 27*3 parts. This 
•compound ignites in the air with great rapidity, yielding 
sulphurous acid in large quantities, and setting fire in any 
open place to all combustible matter, with an energy that is 
peculiarly its own. 
The pyrophorus remained up to our own time a substance, 
mainly, of chemical interest. It was. exhibited at lectures as a 
means for showing off a startling experiment, but not more. 
I can find indeed but one passage in chemical literature which 
refers to the use of spontaneously inflammable substances in 
war. That sentence is in the article on Gunpowder in the 
chemical essays of the learned Dr. Watson, published in 1793. 
He there says, in speaking of the antiquity of gunpowder : — 
There are substances in nature from the combination of which it is possible 
to destroy a ship, a citadel, or an army, by a shower of liquid fire sponta- 
neously lighted in the air. Every person who is aware of the dreadful fiery 
explosion which attends the mixture of two or three quarts of spirit of 
turpentine with strong acid of nitre, must acknowledge the truth of the 
assertion ; but the simple knowledge of effecting such a destruction is a very 
different matter from the knowledge of its practicability, though future ages 
may, perhaps, invent as many different ways of making these substances 
ignite in the air, so as to fall down in drops of fire, as have been invented in 
making gunpowder since the time of Bacon. 
We may pass from the time of Dr. Watson to fihe year 1853. 
In the latter year, the subject of “ liquid fire” began to 
occupy the attention of Mr. Wentworth Scott, then a student 
of chemistry at the Royal College of Chemistry in Oxford Street. 
Mr. Scott commenced his work by making a pyrophorus ; and, 
after various modifications he formed one which promised to 
be most effective, and which, I believe, still might be used 
with considerable effect. He brought a specimen of this to 
mo, at Mortlake, where I then resided, and showed to me its 
properties by filling a small glass shell with the substance, and 
then throwing the shell against a high wall in a garden, so as 
to break the glass and distribute the contents. As the solid 
particles descended, they burst into flame with great force, and 
