On this capital mankind traded for some millenniums, for neither classic times nor the Dark Ages added much to the practical sciences.

But, beginning with the thirteenth century, discovery followed discovery, each more important in its consequences than its last.

One of the first steps was perhaps the recovery of lost ground by the restoration of the classics.

Gothic art and the vernacular literatures testify to the intellectual activity of the time, but they did not create the new elements of life that were brought into being by the inventors.
What a difference in private life was made by the introduction of chimneys and glass windows, for glass, though known to antiquity, was not commonly applied to the openings that, as the etymology of the English word implies, let in the wind! By the fifteenth century the power of lenses to magnify and refract had been utilized, as mirrors, then as spectacles, to be followed two centuries later by telescopes and microscopes.

Useful chemicals were now first applied to various manufacturing processes, such as the tinning of iron.