But it was no worm of a machine. In power it was a very elephant. It could haul loads that would tax the strength of scores of horses. Stumps and boulders were no obstacles in its path. Even ditches could not bar its progress. The machine would waddle down one bank and up the other without the slightest difficulty. It was easily steered; in fact, it could turn around in its own length by traveling forward on one of its chains, or traction-belts, and backward on the other. The machine was particularly adapted to travel on soft or plowed ground, because the broad traction-belts gave it a very wide bearing and spread its weight over a large surface. It was set to work on large farms, hauling gangs of plows and cultivators. Little did Mr. Holt think, as he watched his powerful mechanical elephants at work on the vast Western wheat-fields, that they, or rather their offspring, would some day play a leading role in a war that would rack the whole world. * * * * * But we are getting ahead of our story. To start at the very beginning, we must go back to the time when the first savage warrior used a plank of wood to protect himself from the rocks hurled by his enemy. This was the start of the never-ending competition between arms and armor. As the weapons of offense developed from stone to spear, to arrow, to arquebus, the wooden plank developed into a shield of brass and then of steel; and then, since a separate shield became too bothersome to carry, it was converted into armor that the warrior could wear and so have both hands free for battle. For every improvement in arms there was a corresponding improvement in armor. After gunpowder was invented, the idea of armor for men began to wane, because no armor could be built strong enough to ward off the rifle-bullet and at the same time light enough for a man to wear. The struggle between arms and armor was then confined to the big guns and the steel protection of forts and war-ships.