course of ages, and treasures of science and art are accumulated in these centres of civilization. But—who has made all these marvels?
The combined efforts of scores of generations have contributed towards the achievement of these results. The forests have been cleared centuries ago; millions of men have spent years and years of labour in draining the swamps, in tracing the roads, in building the railways. Other millions have built the cities and created the civilization we boast of. Thousands of inventors, mostly unknown, mostly dying in poverty and neglect, have elaborated the machinery in which man admires his genius. Thousands of writers, philosophers and men of science, supported by many thousands of compositors, printers, and other labourers whose name is legion, have contributed to elaborating and spreading knowledge, to dissipating errors, to creating the atmosphere of scientific thought, without which the marvels of our century never would have been brought to life. The genius of a Mayer and a Grove, the patient work of a Joule, surely have done more to give a new start to modern industry than all the capitalists of the world; but these men of genius themselves are, in their turn, the children of industry: thousands of engines had to transform heat into mechanical force and mechanical force into sound, light, and electricity—and they had to do so for years, every day, under the eyes of humanity—before some of our contemporaries proclaimed the mechanical origin of heat and the correlation of physical forces, and before we ourselves became prepared to listen to them and understand their teachings. Who knows for how many decades we should continue to be ignorant of this theory which now revolutionises industry, were it not for the inventive powers and skill of those unknown workers who have improved the steam-engine, who have brought all its parts to perfection, so as to make steam more manageable than a horse, and to render the use of the engine nearly universal? But the same is true with regard to each smallest part of our machinery. In each machine, however simple, we may read a whole history—a long history of sleepless nights, of delusions and joys, of partial inventions and partial improvements which have brought it to its present state. Nay, nearly every new machine is a synthesis, a result of thousands of partial inventions made, not only in one special department of machinery, but in all departments of the wide field of mechanics.
Our cities, connected by roads and brought into easy communication with all peopled parts of the globe, are the growth of centuries; and each house in these cities, each factory, each shop, derives its value, its very raison d'être, from the fact that it is situated on a
