As with food so with other resources almost as vital. Long ago the savage learned that hickory makes good bows and arrows, that as a club it forms a stout and lasting weapon. He discovered, too, that in these qualities soft woods are inferior and the sumach altogether wanting. Thus, too, with the whole round of stones from which as a warrior or a craftsman he fashioned knives, chisels, arrowheads, axes; it was important that only tough and durable kinds should be employed. No lump of dry clay ever yet served as a hammer or an adze; happy were the tribes, such as those of ancient Britain, who had at hand goodly beds of flint from which a few well directed blows could furnish forth a whole armory of tools and weapons. Properties Modified. In the eating of foods simply as found, in the use of materials for clothing or building just as proffered by the hand of nature, much was learned as to their qualities; some were found good, others indifferent, still others bad. Then followed the art of modifying these qualities, so as to bring, let us say, a fibre or a thong from stiffness to pliability and so make it useful instead of almost worthless. The progress of man from downright savagery may be fairly reckoned by his advances in the power to change the qualities of foods, raiment, materials for shelter, tools, and weapons. These arts of modification go back very far. At first they may have consisted simply in taking advantage of the effects of time. In the very childhood of mankind it must have been noticed that fruit harsh and sour became mellow with keeping, just as now we know that a Baldwin apple harvested in October will be all the better for cellarage until Christmas, the ripening process continuing long after the apple has left its bough. Grains and seeds when newly gathered are usually soft and, at times, somewhat damp; exposed to the sun and dry air for a few days they become hard and remain sound for months or even years of careful storage. In warm weather among many Indian tribes such food was almost the only kind that remained eatable; all else went to swift decay, except in parched districts such as those of Arizona, so that roots, fruits, the flesh of birds, beasts, and fish had to be consumed speedily, a fact that goes far to account for the gluttony of the red man. His stomach was at first his sole warehouse; that filled, any surplus viands went to waste. In frosty weather this havoc ceased; as long as cold lasted there was no loss in his larder. A few communities, as at Luray, Virginia, or at Mammoth Cave, Kentucky, in their huge caverns had storehouses which would preserve food all the months of the twelve. In New Mexico and other arid regions the air is so dry that meat does not fall into decay. How it was discovered that smoke had equal virtue we know not. Probably the fact came out in observing the accidental exposure of a haunch of venison as the reek from a camp-fire sank into its fibres.