In order, therefore, to counteract the wolves, a number of elks select a convenient spot where they can find food, and unite in trampling the snow down so as to sink themselves nearly to their own height below its surface. The wolves never dare attack an Elk-yard, as this enclosure is termed. In the first place, they are always haunted with suspicions of traps, and do not like the look of the yard; and in the next place, if some of the wolves did venture within the fort, the elks would soon demolish them with hoofs and horns. One of these Elk-yards is seen on the left hand of the illustration. WAR AND HUNTING. CHAPTER VII. SCALING INSTRUMENTS.--DEFENCE OF FORT.--IMITATION.--THE FALL-TRAP. Scaling-forks.--The Climbing-spur and its Use.--Larva of the Tiger-beetle.--Hooks of Serpula.--Mr. Gosse’s Description.--Falling Stones.--A Stone rolling down a Precipice.--The Polar Bear and the Walrus.--Imitation.--The Polar Bear and the Seal.--The Esquimaux Hunter “Seal-talking.”--Enticing Mother by means of Young.--The Fall-trap and its Variations.--The Schoolboy’s “Booby-trap.”--Curious Mode of killing Elephants.--The Elephant-spear.--The Hippopotamus-trap of Southern Africa.--The Mangrove and its Seeds.--The Spring-gun and Spring-bow. Before dismissing the subject of the Fortress, we will glance at the Attack and Defence, as seen in Nature and Art. SCALING INSTRUMENTS. We have already seen how the Battering-ram could be worked against the walls of a fort, or how the assailants could scale them by means of the Testudo. There must, however, be occasions when it would be impossible to bring together a sufficiently large body of men to form the Testudo, or even to place ladders, and in such instances it would be necessary that each soldier should be furnished with an instrument by which he could haul himself up the wall. There are many examples still extant of such weapons, which were called “Scaling-forks,” and their general appearance may be known by the two right-hand figures of the cut. The handles of these weapons were very long, and by them the soldier hauled himself to the top of the wall. In some of these instruments the shafts were armed with projecting pegs, set at regular intervals, so that they acted as the steps of a ladder, and rendered the ascent comparatively easy. Many of the long-handled partisans, such as the well-known Jedwood axe, were furnished with a hook upon the back of the blade, so that the weapon served the purpose of a scaling-fork as well as a battle-axe. The Scaling-fork (German _Sturmgabel_), which is shown on the right hand of the illustration, was in use somewhere about A.D. 1500. That which is shown next to it is about a hundred years later. [Illustration: WALRUS TUSKS. LARVA OF TIGER-BEETLE. CLIMBING-SPUR. SCALING-FORKS. HOOKS OF SERPULA.]