amphitheatres and circuses; structures for public service, as
city-halls, court-houses, prisons, hospitals, thermæ, markets,
warehouses, slaughter-houses, railway-stations, light-houses, bridges
and aqueducts; finally, private dwellings, as palaces, mansions, city
and country residences, châteaux and villas.

[Illustration: Memorial to the Heroes of the Franco Prussian War,
Berlin.]

The first care of all social organizations, at their inception, must
have been to provide shelter against inclement weather. In primitive
times society was composed of shepherds, or agriculturists, or hunters,
and it is presumable that each of these groups adopted a shelter suited
to its nomadic or sedentary tastes. For this reason to shepherds is
attributed the invention of the tent, a portable habitation which they
could take with them from valley to valley, wherever they led their
flocks to pasture; agriculturists fixed to the soil which they tilled,
dwelling in the plains and along the river banks, must have found the
hut better adapted to their wants, while the hunters, stealing through
the forests, ambushed in the mountains, or stationed on the seashore,
naturally took safety in caves, or dug holes for themselves in the
earth, or hollowed out grottos in the rocks.

An imitation of the tent is found later on in the form of the Chinese
and Japanese structures; the principle of the cave appears developed in
the subterranean dwellings of the people of India and Nubia; while the
hut is the point of departure for all Greek and Roman architecture.

As soon as man had contrived a shelter for himself, before considering
improvements that might be made in it, he turned his thoughts toward the