Even such primitive appliances greatly extended man's con trol over the world about him. With the stone ax thrown from the hand he could kill animals in full flight. The spear enabled him at a safer distance to kill some of his most dan gerous enemies. The bow and arrow and the use of fire must have made his supremacy far more secure. For thousands of years, however, the first tools changed but slowly. It was difficult to get beyond the simple, natural implements picked up by chance.
§ 11. The gradual improvement of indirect agents. In the course of centuries tools and weapons gradually became more efficient. Flint and stone forms were copied in bronze and in iron. Their number and variety steadily increased. Better and more numerous hammers, axes, spears, bows, and arrows were made. Domestic animals were increasingly util ized for food, clothing, and for the carrying of burdens. As a rule the stocks of goods with indirect uses accumulated by primitive man differed little in physical character from his goods with direct uses. Many of them, indeed, were things having alternative uses, some direct, others indirect. It is likely that horses were used to carry men on their backs long before they were taught to carry other burdens or to draw heavy loads. The weapons of the chase were as much a means of sport as a means of securing food, and such things as cloth ing, tools, and weapons, and even horses and slaves, seem to have been regarded by primitive man as agents to use di rectly for enjoyment rather than as merely indirect means of getting other goods. This attitude of mind probably helps explain the custom of burying such things with the owner in his grave—a practice which greatly hindered progress, as it kept the primitive community in poverty. Where such cus toms were not in vogue man's control over his environment developed through the gradual increase in his instrumental equipment from generation to generation.
§ 12. Tools and machines. It is not easy, perhaps not im portant, to draw a sharp line of distinction between the ma chine and the tool. Tools are portions of matter, such as bone, wood, iron, which man guides and directs in applying his energy to things. The simple hoe held in the hand and moved by man's own strength was attached to the beast of burden and became a plow or harrow, still guided by man. A machine may be defined as a mechanical device by which power is applied in an automatically repeated manner, to change the place or form of things. A machine may be moved by the foot, but the hand is the great tool-using member. A
simple, single piece, that can be taken into the hand, as a spade, a hammer, a knife, is clearly a tool ; a combination of parts, such as wheels, levers, pulleys, etc., moving upon each other, is clearly a machine. It is doubtful whether the plow should be called a machine. The simplest machine is but a slight adaptation of the tool, by which power may be applied in an automatically repeated manner. The drag develops into the cart, a simple machine. The spinning stick, a tool used in ancient times, developed into the Saxon spinning-wheel of the sixteenth century, the form used when America was colo nized. Wind and water were made to turn wheels to supply the power for moving tools, to grind the corn, and to lift the hammer too heavy for man's strength. The use of power de rived from nature, while not the most essential mark of ma chines, is the most characteristic feature of their modern de velopment. Hand machines, such as the handpress and type writer, have had important industrial results, but it is the use of power that has led to the results of greatest significance in recent times.
§ 13. The age of machinery. Inventions, new machines, and new processes, tho not frequent, were not unknown in the Middle Ages; but no one class of machines took possession of whole fields of industry. The great industrial changes in the Middle Ages generally grew out of political changes, or of changes of routes of trade whereby large industries were dis turbed, or of changes in the use of land through new methods and the bringing into use of land in other places. The indus trial changes in England at the end of the eighteenth century, and a little more tardily throughout western Europe and the United States, on the contrary, were due mainly to great me chanical inventions. The age of machinery is, therefore, said to begin with the eighteenth century. The development of the textile machines for cotton and wool spinning and weaving marks the beginning of the movement. Here for the first time were inventions in such numbers, of such a nature, and under such conditions that they were rapidly and widely applied, affecting the lives of a great number of workers. The steam engine at the same time opened up the long line of mechanical inventions by which wood and iron are shaped and wrought, and the iron industry underwent notable developments. Since that time have taken place in all western countries that rapid expansion in the use of machines and those notable changes in industrial organization which distinguish our era from all others.