In discussing the phenomena of the highly centralized society in which he lived, Mill defined capital “as the accumulated stock of human labour.” In other words, capital may be considered as stored energy; but most of this energy flows in fixed channels, money alone is capable of being transmuted immediately into any form of activity. Therefore the influx of the Indian treasure, by adding considerably to the nation’s cash capital, not only increased its stock of energy, but added much to its flexibility and the rapidity of its movement. Very soon after Plassey the Bengal plunder began to arrive in London, and the effect appears to have been instantaneous, for all authorities agree that the “industrial revolution,” the event which has divided the nineteenth century from all antecedent time, began with the year 1760. Prior to 1760, according to Baines, the machinery used for spinning cotton in Lancashire was almost as simple as in India;[337] while about 1750 the English iron industry was in full decline because of the destruction of the forests for fuel. At that time four-fifths of the iron in use in the kingdom came from Sweden. Plassey was fought in 1757, and probably nothing has ever equalled the rapidity of the change which followed. In 1760 the flying-shuttle appeared, and coal began to replace wood in smelting. In 1764 Hargreaves invented the spinning-jenny, in 1779 Crompton contrived the mule, in 1785 Cartwright patented the power-loom, and, chief of all, in 1768 Watt matured the steam-engine, the most perfect of all vents of centralizing energy. Hut though these machines served as outlets for the accelerating movement of the time, they did not cause that acceleration. In themselves inventions are passive, many of the most important having lain dormant for centuries, waiting for a sufficient store of force to have accumulated to set them working. That store must always take the shape of money, and money not hoarded, but in motion.