The mechanical revolution, the process of mechanical invention and discovery, was a new thing in human experience and it went on regardless of the social, political, economic and industrial consequences it might produce. The industrial revolution, on the other hand, like most other human affairs, was and is more and more profoundly changed and deflected by the constant variation in human conditions caused by the mechanical revolution. And the essential difference between the amassing of riches, the extinction of small farmers and small business men, and the phase of big finance in the latter centuries of the Roman Republic on the one hand, and the very similar concentration of capital in the eighteenth and nineteenth centuries on the other, lies in the profound difference in the character of labour that the mechanical revolution was bringing about. The power of the old world was human power; everything depended ultimately upon the driving power of human muscle, the muscle of ignorant and subjugated men. A little animal muscle, supplied by draft oxen, horse traction and the like, contributed. Where a weight had to be lifted, men lifted it; where a rock had to be quarried, men chipped it out; where a field had to be ploughed, men and oxen ploughed it; the Roman equivalent of the steamship was the galley with its bank of sweating rowers. A vast proportion of mankind in the early civilizations were employed in purely mechanical drudgery. At its onset, power-driven machinery did not seem to promise any release from such unintelligent toil. Great gangs of men were employed in excavating canals, in making railway cuttings and embankments, and the like. The number of miners increased enormously. But the extension of facilities and the output of commodities increased much more. And as the nineteenth century went on, the plain logic of the new situation asserted itself more clearly. Human beings were no longer wanted as a source of mere indiscriminated power. What could be done mechanically by a human being could be done faster and better by a machine. The human being was needed now only where choice and intelligence had to be exercised. Human beings were wanted only as human beings. The drudge, on whom all the previous civilizations had rested, the creature of mere obedience, the man whose brains were superfluous, had become unnecessary to the welfare of mankind. INCIDENT IN THE DAYS OF THE SLAVE TRADE INCIDENT IN THE DAYS OF THE SLAVE TRADE _From a print after Morland in the British Museum_