Then he remembered that there are natural phenomena to which some one has given the name “acoustic shadows.”  If you stand in an acoustic shadow there is one direction from which you will hear nothing.  At the battle 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 the opposite side of the Chickahominy valley heard nothing of what they clearly saw.  The bombardment of Port Royal, heard and felt at St. Augustine, a hundred and fifty miles to the south, was inaudible two miles to the north in a still atmosphere.  A few days before the surrender at Appomattox a thunderous engagement between the commands of Sheridan and Pickett was unknown to the latter commander, a mile in the rear of his own line.

These instances were not known to the man of whom we write, but less striking ones of the same character had not escaped his observation.  He was profoundly disquieted, but for another reason than the uncanny silence of that moonlight march.

“Good Lord!” he said to himself—­and again it was as if another had spoken his thought—­“if those people are what I take them to be we have lost the battle and they are moving on Nashville!”

Then came a thought of self—­an apprehension—­a strong sense of personal peril, such as in another we call fear.  He stepped quickly into the shadow of a tree.  And still the silent battalions moved slowly forward in the haze.

The chill of a sudden breeze upon the back of his neck drew his attention to the quarter whence it came, and turning to the east he saw a faint gray light along the horizon—­the first sign of returning day.  This increased his apprehension.

“I must get away from here,” he thought, “or I shall be discovered and taken.”

He moved out of the shadow, walking rapidly toward the graying east.  From the safer seclusion of a clump of cedars he looked back.  The entire column had passed out of sight:  the straight white road lay bare and desolate in the moonlight!

Puzzled before, he was now inexpressibly astonished.  So swift a passing of so slow an army!—­he could not comprehend it.  Minute after minute passed unnoted; he had lost his sense of time.  He sought with a terrible earnestness a solution of the mystery, but sought in vain.  When at last he roused himself from his abstraction the sun’s rim was visible above the hills, but in the new conditions he found no other light than that of day; his understanding was involved as darkly in doubt as before.

On every side lay cultivated fields showing no sign of war and war’s ravages.  From the chimneys of the farmhouses thin ascensions of blue smoke signaled preparations for a day’s peaceful toil.  Having stilled its immemorial allocution to the moon, the watch-dog was assisting a negro who, prefixing a team of mules to the plow, was flatting and sharping contentedly at his task.  The hero of this tale stared stupidly at the pastoral picture as if he had never seen such a thing in all his life; then he put his hand to his head, passed it through his hair and, withdrawing it, attentively considered the palm—­a singular thing to do.  Apparently reassured by the act, he walked confidently toward the road.