One summer night a man stood on a low hill overlooking a wide expanse of forest and field. By the full moon hanging low in the west he knew what he might not have known otherwise: that it was near the hour of dawn. A light mist lay along the earth, partly veiling the lower features of the landscape, but above it the taller trees showed in well- defined masses against a clear sky.
Two or three farmhouses were visible through the haze, but in none of them, naturally, was a light.Nowhere, in- deed, was any sign or suggestion of life except the barkingof a distant dog, which, repeated with mechanical iteration, servedrather to accentuate than dispel the loneliness of the scene.
The man looked curiously about him on all sides, as one who amongfamiliar surroundings is unable to determine his exact place and part inthe scheme of things. It is so, perhaps, that we shall act when, risenfrom the dead, we await the call to judgment.
A hundred yards away was a straight road, show- ing white in themoonlight. Endeavouring to orient himself, as a surveyor or navigatormight say, the man moved his eyes slowly along its visible length and ata distance of a quarter-mile to the south of his station saw, dim andgrey in the haze, a group of horsemen riding to the north. Behind themwere men afoot, marching in column, with dimly gleaming rifles aslantabove their shoulders.
They moved slowly and in silence. Another groupof horsemen, another regiment of infantry, another and another –all inunceasing motion toward the man’s point of view, past it, and beyond. Abattery of artillery followed, the cannoneers riding with folded arms onlimber and caisson. And still the interminable procession came out ofthe obscurity to south and passed into the obscurity to north, withnever a sound of voice, nor hoof, nor wheel.
The man could not rightly understand: he thought himself deaf; saidso, and heard his own voice, al- though it had an unfamiliar qualitythat almost alarmed him; it disappointed his ear’s expectancy in thematter of timbre and resonance. But he was not deaf, and that for themoment sufficed.
Then he remembered that there are natural phe- nomena to which someone has given the name ‘acoustic shadows.’ If you stand in an acousticshadow there is one direction from which you will hear nothing. At thebattle of Gaines’s Mill, one of the fiercest conflicts of the Civil War, with a hundred guns in play, spectators a mile and a half away on theopposite side of the Chickahominy Valley heard nothing of what theyclearly saw.
The bombardment of Port Royal, heard and felt at St.Augustine, a hundred and fifty miles to the south, was inaudible twomiles to the north in a still atmosphere. A few days before thesurrender at Ap- pomattox a thunderous engagement between the commandsof Sheridan and Pickett was unknown to the latter commander, a mile inthe rear of his own line.