To a Spaniard all trees except fruit-trees mean so many cubic feet of wood for building or charcoal. As Spain and Italy both know, climates change when the forests go, and the crops suffer from long droughts or heavy deluges which sweep the soil bodily away in spite of laboriously-built stone terraces or concrete-lined water ducts. But that is for mañana.

Concrete-lined trenches, with spacious and well-furnished bomb-proofs, with phonographs, printing presses, and occasional dramatic performances for lightening the soldiers' lot present an impressive elaboration of the muddy ditches of Virginia and Mississippi.

The house had been built on the slope of a gentle rise so that you might walk from the first-floor window on to the grassy lawn at the back of the house but for two important obstacles, the first being represented by the bars which protected the window and the second by a deep area, concrete-lined, which formed a trench too wide to jump. She could see, however, that the grounds were extensive.

The La Salle Street tunnel was soon aglow with white plaster and electric lights. The long streets and avenues of the North Side were threaded with concrete-lined conduits and heavy street-rails. The powerhouses were completed and the system was started, even while the contracts for the changes on the West Side were being let.

The bulk of the dam rests on impermeable material of sufficient supporting power. The locks and spillway are considered a part of the dam. The locks are built in an excavation at the east end of the dam, in rock, and will lift vessels from the Atlantic level to the level of the Lake of Gatun. The spillway is a concrete-lined opening cut through a hill of rock near the center of the dam.