Ch. What is that?
Fa. It comprehends the knowledge of all the properties of metals and minerals, salts, sulphur, oils, and gums, and of the action of fire, and water, and air upon all substances, and the effects of mixing different things together. Gunpowder is a mixture of three things only; saltpetre or nitre, sulphur or brimstone, and charcoal. But who could have thought such a wonderful effect would have been produced by it?
Ch. Was it not first discovered by accident?
Fa. Yes; but it was by one who was making chymical experiments, and many more experiments have been employed to bring it to perfection.
Ch. But need a captain know how to make gunpowder and cannon?
Fa. It is not necessary, though it may often be useful to him. However, it is quite necessary that he should know how to employ them. Now the sciences of gunnery and fortification depend entirely upon mathematical principles; for by these are calculated the direction of a ball through the air, the distance it would reach to, and the force with which it will strike any thing. All engineers, therefore, must be good mathematicians.
Ch. But I think have heard of gunners being little better than common men.
Fa. True—there is a way of doing that business, as well as many others, by mere practice: and an uneducated man may acquire skill in pointing a cannon, as well as in shooting with a common gun. But this is only in ordinary cases, and an abler head is required to direct. Well—now suppose your ship completely fitted out for sea, and the wind blowing fair; how will you navigate her?
Ch. I would spread the sails, and steer by the rudder.
Fa. Very well—but how would you find your way to the port you are bound for?