The use of pyrotechnic mixtures for military purposes is the basis of artillery, and one might almost say the foundation of chemistry. Before the age of the alchemist men were at work endeavouring to produce some weapon which would give them an advantage over their enemies. Of the natural phenomena none made so strong an appeal as fire, which from earliest times had been a mysterious and therefore terrible element.
The early use of fire or pyrotechnic mixtures gave the users so decided an advantage over their enemies that their use was chronicled by historians of the day either on the side of the victors as a pæan of praise for their invincible weapon, or as an excuse for defeat on the side of the vanquished.
Such reports are necessarily vague and exaggerated, vague because the writer had no technical knowledge of the subject, and the users naturally wished for secrecy and exaggerated because exaggeration increased the value of the weapon.
It is from such reports that we obtain our information about Greek fire and similar compositions, and when one considers that the translations were generally biased, in most cases unintentionally but still biased, in favour of reading into passages referring to fire or projectiles an early reference to gunpowder, guns or some unknown pyrotechnic effect, it is obvious that all information so gained must be accepted with a considerable amount of reserve.
The translators, too, in many cases were men of no technical knowledge, which made them even more prone to fall into errors which would be avoided by the expert.
Of the mass of writing dealing with the subject, the work of two writers stands out prominently—the late Mr. Oscar Guttman in his “History of Explosives,” and Col. H. W. L. Hime in his “Origin of Artillery,” whose observations cover the field of information on the subject, although approaching from slightly different angles.
Neither, however, gives an exact explanation satisfactorily covering the projection of Greek or sea fire. Col. Hime, rejecting earlier theories, goes somewhat to the other extreme: he denies the knowledge of saltpetre before the twelfth century, but attempts to explain the phenomenon by the use of phosphide of calcium.
He premises four conditions to be filled by the weapon or apparatus. These conditions are fulfilled by the explanation already briefly touched upon on page 15, and the writer is convinced that this simple although apparently little known phenomenon is the true explanation of the terrible, mysterious Greek or sea fire.
If a mixture of saltpetre, pitch, and sulphur is charged into a long tube sufficiently strong and ignited it will burn, giving off dense smoke, for a short time, when it appears to choke momentarily. This choking is followed by a more or less violent outburst, which may be likened to a “cough,” projecting a burning mass of composition to a considerable distance; the action is repeated with surprising regularity during the burning of the whole of the composition throughout the length of the tube, and will, the writer is confident, satisfy any unbiased observer that here is the true explanation of the phenomenon.
Let us see how the requirements mentioned by Col. Hime are fulfilled. The first, “It was a wet fire,” i.e., its action necessarily connected in some way with water or the sea, and as a matter of fact it was used at sea with great success on many occasions. May not a “wet fire” be a way of saying “a molten, viscous mass of fire”? The masses would float and although some might become extinguished, some would probably burn on the surface of the water; also its use at sea would, with a range up to a hundred yards, be quite as easy as on land.