273 Thus, for instance, the plow and the gun are machines, the spade and the blow-pipe are tools. A hammer may be considered as a hard, insensible fist; the bellows as a pair of very strong and durable lungs. Tongs take the place of fingers, just as a spoon does of the empty hand, and the knife the place of the teeth. A great number of machines, on the other hand, may be compared to a complete workman. Thus, the action of the mill which grinds grain has very little resemblance to the blowing of the wind or the running of the water, whereas the rising and falling of the pestle in the small mortar for throwing grenades corresponds to the motion of the arm. (_Rau_, Lehrbuch I, § 125.) The infinite number of functions of which our members are capable is related to their inability to attain alone the greater number of their ends. Hence animals which require no tools can undertake to achieve very few things. “Man is a tool-making animal.” (_B. Franklin._) 274 This is seen most clearly in the history of the grinding of corn. In the time of Moses, and even of Homer, there were only hand-mills, and originally only mortars. Later, mills set in motion by horse-power were employed. Shortly after Cicero’s time, mills driven by water-power came into use. _Brunck_, Analecta, II, 119, Ep. 39. Mills built on pontoons do not date farther back than the time of Belisarius. Wind-mills have been known since the ninth century; Dutch wind-mills, only since the middle of the 16th century. See _Beckman_, Beiträge zur Geschichte der Erfindungen II, I ff. 275 Compare _Plato_, Polit., 280. 276 Thus, _Ganilh_, Théorie de l’Economie politique I, 133, calls the knowledge, talents and probity of merchants, as well as their reputation, valuable parts of their capital in trade. See, also, _Möser_, Patriot. Ph. II, 26. See some happy observations on the intellectual capital of nations, as consisting of “known and unknown preparatory labor through their history,” in _Lotze_, Mikrokosomos II, 353 seq. 277 Compare _Dietzel_, System der Staatsanleihen (1856), 71 ff. And, earlier yet, _Ad. Müller_ had looked upon taxes not in the light of an insurance premium, but as “the interest of the invisible and yet absolutely necessary intellectual capital of the nation.” (Elemente, III, 75.) Of course, the State is much more than a species of capital; just as a Gothic cathedral is something more than a piece of masonry, but does not on that account cease to be a piece of masonry. _ 278 J. B. Say_, Traité d’Economie Politique I, ch. 10. Only think of what is known in physiology as the change or transformation of matter (_Stoffwechsel!_).