Paving was followed by attempts, often of an imperfect kind, at the construction of drains and sewers.  It had become obvious to all reflecting men that these were necessary to the preservation of health, not only in towns, but in isolated houses.  Then followed the lighting of the public thoroughfares.  At first houses facing the streets were compelled to have candles or lamps in their windows; next the system that had been followed with so much advantage in Cordova and Granada—­of having public lamps—­was tried, but this was not brought to perfection until the present century, when lighting by gas was invented.  Contemporaneously with public lamps were improved organizations for night-watchmen and police.

By the sixteenth century, mechanical inventions and manufacturing improvements were exercising a conspicuous influence on domestic and social life.  There were looking-glasses and clocks on the walls, mantels over the fireplaces.  Though in many districts the kitchen-fire was still supplied with turf, the use of coal began to prevail.  The table in the dining-room offered new delicacies; commerce was bringing to it foreign products; the coarse drinks of the North were supplanted by the delicate wines of the South.  Ice-houses were constructed.  The bolting of flour, introduced at the windmills, had given whiter and finer bread.  By degrees things that had been rarities became common—­Indian-corn, the potato, the turkey, and, conspicuous in the long list, tobacco.  Forks, an Italian invention, displaced the filthy use of the fingers.  It may be said that the diet of civilized men now underwent a radical change.  Tea came from China, coffee from Arabia, the use of sugar from India, and these to no insignificant degree supplanted fermented liquors.  Carpets replaced on the floors the layer of straw; in the chambers there appeared better beds, in the wardrobes cleaner and more frequently-changed clothing.  In many towns the aqueduct was substituted for the public fountain and the street-pump.  Ceilings which in the old days would have been dingy with soot and dirt, were now decorated with ornamental frescoes.  Baths were more commonly resorted to; there was less need to use perfumery for the concealment of personal odors.  An increasing taste for the innocent pleasures of horticulture was manifested, by the introduction of many foreign flowers in the gardens—­the tuberose, the auricula, the crown imperial, the Persian lily, the ranunculus, and African marigolds.  In the streets there appeared sedans, then close carriages, and at length hackney-coaches.

Among the dull rustics mechanical improvements forced their way, and gradually attained, in the implements for ploughing, sowing, mowing, reaping, thrashing, the perfection of our own times.

Mercantile inventions.  It began to be recognized, in spite of the preaching of the mendicant orders, that poverty is the source of crime, the obstruction to knowledge; that the pursuit of riches by commerce is far better than the acquisition of power by war.  For, though it may be true, as Montesquieu says, that, while commerce unites nations, it antagonizes individuals, and makes a traffic of morality, it alone can give unity to the world; its dream, its hope, is universal peace.