If you enter a modern coal-mine you will see a man in charge of a huge machine that raises and lowers a cage. In his hand he holds a lever that stops and reverses the course of the machine; he lowers it and the cage reverses its course in the twinkling of an eye; he sends it upwards or downwards into the depths of the shaft with a giddy swiftness. All attention, he follows with his eyes fixed on an indicator which shows him, on a small scale, at which point of the shaft the cage is at each second of its progress; and as soon as the indicator has reached a certain level, he suddenly stops the course of the cage, not a yard higher nor lower than the required spot. And no sooner have the colliers unloaded their coal-wagonettes, and pushed empty ones instead, than he reverses the lever and again sends the cage back into space. During eight or ten consecutive hours every day he must keep the same strain of attention. Should his brain relax for a moment, the cage would inevitably strike against the gear, break its wheels, snap the rope, crush men, and put a stop to all work in the mine. Should he waste three seconds at each touch of the lever,--the extraction, in our modern, perfected mines, would be reduced from twenty to fifty tons a day. Is it he who is the most necessary man in the mine? Or, is it perhaps the boy who signals to him from below to raise the cage? Is it the miner at the bottom of the shaft, who risks his life every instant, and who will some day be killed by fire-damp? Or is it the engineer, who would lose the layer of coal, and would cause the miners to dig on rock by a simple mistake in his calculations? Or is it the mine owner who has put his capital into the mine, and who has perhaps, contrary to expert advice, asserted that excellent coal would be found there? All those who are engaged in the mine contribute to the extraction of coal in proportion to their strength, their energy, their knowledge, their intelligence, and their skill. And we may say that all have the right to _live_, to satisfy their needs, and even their whims, when the necessaries of life have been secured for all. But how can we appraise the work of each one of them? And, moreover, Is the coal they have extracted entirely _their_ work? Is it not also the work of the men who have built the railway leading to the mine and the roads that radiate from all the railway stations? Is it not also the work of those that have tilled and sown the fields, extracted iron, cut wood in the forests, built the machines that burn coal, slowly developed the mining industry altogether, and so on?