WE will now take some of the analogies between Projectile Weapons of Art and Nature, selecting those in which the propulsive power is air or gases within a tube. Whether the weapon be a blow-gun, an air-gun, or a firearm of any description, the principle is the same. We will take them in succession, choosing first those of the simplest and most primitive character.

Taking ourselves as examples, and looking upon the toys of children as precursors of more important inventions, we find that the simplest and most primitive of projectiles is the Pea-shooter, so familiar to all boys.

Insignificant as is the little tin tube, and small as are the missiles which are propelled through it, the blow which can be struck by a pea properly shot is no trifle. At college I have seen a night attack upon an undergraduate's rooms successfully repelled by a pea-shooter made for the nonce of a glass tube, the owner of the rooms having a taste for chemicals, and possessing a fair stock of the usual apparatus. Though the assaulted rooms were on the top set, and the assailants began their storming approaches below, the peas were too much for the stones, taking stinging effect on the hands and faces, and preventing any good aim being taken at the windows. Only two panes of glass were broken through a siege that lasted for several hours.