But even those advantages would have had little effect, at any rate quickly, had it not been for a great discovery, one of the great discoveries of the world, one to be reckoned with the discovery of the ocean, of iron or of fire, a discovery which has caused one of the great revolutions, because it was a discovery of a new way of controlling energy.
We have assumed that the fundamental necessities of human life are food and clothing. The energy which gives the ability to do work, possessed by every human being, has been assimilated by means of food. The energy of the individual has been to a large extent saved in these regions by means of clothing. In very early times, or among savage races, food and clothing may have been obtained in other ways, but during all historic times, among all peoples that have ever counted, food and clothing have been obtained under two sets of social conditions : they have been obtained from more or less domesticated animals, or by cultivating the ground.
All the food and all the clothing required was raised by each individual or family, or at most a very small association of people. Each of these communities was practically independent of the rest of the world, except in so far as it was open to interference from outside by others who wished forcibly to seize the stores of food energy or of clothing protection.
In other words, energy was largely saved by indi viduals ; practically all mechanical work was done by individuals or animals, and the limit of the amount of work that could be done was the amount that a few men or a few animals could do. There were one or two exceptions to this almost general rule, but they only emphasize how very general the rule was that agriculture and pastoral pursuits were supreme, and that the individual man's work was the maximum that could be attempted.
Mills for grinding corn for food were in later times either wind or water driven. We see now in country places a mill here and a mill there. We think of them rather as picturesque objects than as instruments of extraordinary value. If we see them turn laboriously, almost the last idea that the rumbling old things suggest is that, just as they stand, they were for many hundreds of years the greatest machines, the machines giving out most energy, known to man. Small as it was, the mill was almost the only instrument where energy of a larger amount than that supplied by one man's body was used. It was the only instrument whereby energy other than food energy could be used for the service of man. There had been a great revolution when the daily
domestic labour of grinding at the mill was given up, and the supply ground once for all at the common mill by power, however feeble, according to our ideas of what power is. The miller was an important personage in those days ; the mill was an important centre. Many are the towns and villages that owe their position to the existence of a mill beside a stream, not in Britain only, but all over the Old World and those parts of the New which have been settled for more than a hundred years. The importance of this very feeble way of utilizing power brings home to us clearly how very small were the greatest power schemes, that could be attempted. By the mill some small part of the domestic labour necessary to prepare food was done away with, but all clothing, every stitch of it, to save the heat-energy of the human body, was hand made. From the curing of the skin, the shearing of the sheep, and the planting of the flax, to the making of the actual garment, all the operations were performed by individuals, and usually by the individual who was going to wear the garment or by a member of his family. A great advance was made when the trade of weaver appeared and the fabric was woven, still by single man-power, it is true, but by the aid of a loom. Herein lay the importance of the weaving guilds of the Middle Ages in North Italy, and the importance of Britain because she could breed sheep.
There was very little commerce. Commerce implies that something can be produced more cheaply, i. e. with less expenditure of energy, in one place than an other, and can be carried cheaply from the place of production to the place of consumption. Now in all the Middle Ages, in all the time that elapsed up to a hundred years ago, it was only in exceptional circum stances that bulky things could stand carriage. The cost, i. e. the expenditure of energy necessary to convey large heavy things any distance, was so great that, however cheaply they might be produced originally, the amount of energy expended on them to carry them any distance, added to that necessary to produce them, was too great to save anything in the long run. Even after the Portuguese discovered the sea way to the Indies, the whole amount of the spices brought to Europe in a year would go into the fore-hold of a modern coasting tramp, and spices were almost the only things which it paid to carry.