These three sea-salients were greatly armed for defense. In each harbor lay batteries of 12-inch all-steel rifled cannon. Hidden under facings of earth, steel and concrete, they sat on disappearing carriages and pneumatic gun-lifts that would swing them up as if they weighed ounces instead of tons, and instantly plunge them back again into cover after firing. Deep under earth embankments, squatting in concrete-lined graves, 12-inch mortars, sixteen to a group, stared upward at the patches of sky over their heads, which was all that their men would see while they were firing, however bitter the fight might be. A single shot from one of the long, graceful rifles might sink a ship, if it were well placed. A single salvo from the mortars, the sixteen firing together, assuredly would. And they could do it. Aimed by mathematics, they were sure to strike the spot.[38] A score of serving devices in the defenses were slaves to the steel champions. Searchlights in armor waited like men-at-arms to point with a long white finger at their prey. Mine fields and emplacements and cable conduits were there to force the ships to steer where the guns could strike them most surely. Masked by trees and mounds, concealed by every device against betrayal, were range-finders and fire-control stations. Here sat experts who had studied the most occult questions of arithmetic, geometry, surveying, navigation, and cartography for one purpose--to direct those long guns true. They were provided with exquisite instruments for calculating angles and distances to an inch, though the point to be ascertained were ten nautical miles and more away. Before them lay charts of the sea-area that they were guarding. Let a ship come within the limit of their apparatus, and in the time required to speak into a telephone the gun-pits miles away down the defense-line would crack with the explosion of tons of smokeless powder. They were nearly perfect, those works--as engineering works. They were fully armed with the engines to make them malignant to the ultimate fatal degree. The ten-mile area of sea that lay so bright and dimpled that morning might well have been black as the Wings of Death; for a few little motions of the waiting men under the pretty grassy mounds would unfold those pinions. _The Joint in America’s Armor_ But under the iron visages was weakness. In none of the defenses on this morning when the time had come for their test, were there more than one-half the number of men required to hold them.[39] They could fight the guns, so long as the action remained a ship-to-fort action; but if the enemy attacked at the rear, from the land, they were not in sufficient force to meet him and throw him back. Attacked from the land, the men of the defenses would have to retire to the inner keep and fight from shelter with rapid-fire guns. And when the defenses thus began to defend themselves, their hour would have struck.[40]