CHAPTER III

THE ANIMAL MACHINE

The oldest machine in existence, p. 43--The relation of muscle to machinery, p. 44--How muscular energy is applied, p. 44--The two types of muscles, p. 45--How the nerve-telegraph controls the muscles, p. 47--The nature of muscular action, p. 49--Applications of muscular energy, p. 52--The development of the knife and saw, p. 53--The wheel and axle, p. 55--Modified levers, p. 57--Domesticated animals, p. 59--Early application of horse-power, p. 60--The horse-power as the standard of the world's work, p. 61.