gathering of honey by the bee or the hoarding of nuts by the squirrel.
Another important way of making changes in the composi tion of materials is by breeding and raising domestic animals. Animal growth transforms the food elements into new sub stances, such as wool, hides, furs, feathers, fat, eggs, bristles, etc. Still another way is seen in the chemical processes of manufacturing, such as iron smelting and other metallurgical operations, tanning, the dyeing of clothes, and the preparation of food as in baking, fermenting, distilling, etc.
To make possible all the changes which man desires in the composition of things, an enormous equipment of indirect agents must be permanently maintained—such things as cul tivated soil, agricultural implements, seeds, animals, fertilizers, chemical agents, vats, caldrons, furnaces, fuel, etc., etc. All these things are of value to man (among other reasons) be cause of the changes in stuff or material which they help to bring about.
§ 8. Agencies for changing the form of things. The al terations in the materials of which things are composed that do not involve chemical or organic changes may be classed under the heading of changes of form. It is probably best to class here most of the operations in the so-called extractive industries (other than agriculture). Such are the processes of mining or of quarrying in which organic or mineral mate rials are blasted, dug, or broken into sizes and shapes con venient for removal; and the process of forestry in which timber is cut and prepared to be taken from its place of growth. There is always, however, a considerable amount of place change involved in these processes. Here, certainly, with form-change may be classed the grouping or arranging of things in new physical relationships—such mechanical opera tions, for example, as cutting, sawing, splitting, grinding, put ting together with nails, screws, or glue, roughening, polish ing, etc., etc. Changes of this sort—as well as chemical changes—play a large part likewise in the processes of agri culture; for example, in plowing, in hoeing, in cutting grain, in trimming trees, and in shearing sheep. Some of the most familiar and typical instances are found in manufacturing establishments, such as sawmills, planing mills, and factories for shaping wood, iron, leather, clay, and other materials. A
large part of the preparation of food involves changes of this kind. The performance of all these operations involves, of course, an enormous equipment of indirect agents—in the home, on the farm, in shop and factory. This includes a large part of the stock of tools and machines, tho many of these are used also in effecting changes in stuff, place, and time.
§ 9. Natural members as agents in effecting changes of form. In the course of evolution animals have developed spe cial organs which enable them to bring about changes in the form of things. The foot, the paw, and the tail, subserving largely the purposes of locomotion, are also of use in making physical changes in the environment. Animals have teeth to crush and cut; claws and nails to scratch and tear, pick and bore; hoofs to strike; horns and tusks to pierce, push, and crush. The sword of the swordfish, the proboscis of the mos quito, and the trunk of the elephant are highly specialized organs for acting upon the environment.
Compared with many animals man is in many respects poorly equipped with such natural weapons and agents. The human hand, however, is perhaps on the whole the most adaptable and effective agent which nature has produced.
§ 10. The use of tools by man. Man is the tool-using ani mal. The intelligence which directs and guides the hand has enabled man to contrive external agents of the most marvelous ingenuity and power. The first tools, as is shown in every anthropological museum, were but natural objects taken to increase the efficiency of man's body in acting upon the outer material world. These first inventions were evidently hit upon almost by chance, and yet probably not without some dim per ception of the fitness of indirect means to attain the ends de sired. The stone held in the hand multiplies many fold the force of the blow. The chance piece of sharp or jagged flint is vastly more effective than nails or claws in cutting and tear ing. Boulders and stones shaped by nature or very slightly modified were the first rude hammers, axes, and knives. The log used as a roller under a heavy load seems to have been the earliest form of the wheel.