work that has been intentionally directed to warlike ends. Still they have owed much to such work and before I examine cases in which War has appropriated discoveries not made directly for its purposes I wish to shew you what Science can do when it takes in hand a purely military subject. With this object I will take the subject of Explosives, the basis of all modern warfare, and ask you to examine with me its history and present position.
The Science of Explosives is merely a study of the phenomena of Combustion. An explosive is nothing other than a combustible substance that can burn rapidly without needing to be in communication with the external air. This may sound a very gentle definition of so terrifying a thing as an explosive, the very name of which suggests the possession of enormous force under uncertain control. People are prepared to credit such a substance with secret stores of power wholly surpassing those that are possessed by other bodies. This however is far from being the case. It may surprise 16