"And the Lord said unto Satan, Whence comest thou? Then Satan answered the Lord, and said, From going to and fro in the earth, and from walking up and down in it."--_Job i. 7._ The spy is the most dangerous man in the army; more is he to be feared than the genius of a Napoleon or a Lee. The sphere in which he operates has no duplicate in military activities; his bravery, boldness, and daring are unexcelled. Whether he be called from the ranks, or from among the commissioned officers, his counsel and suggestions get a hearing in the highest commandery of the army. The movements of a spy are unknown even to his own corps, much less to the enemy. After receiving authority for such a perilous undertaking he is a free lance, going and coming at will. Not only does he go beyond the enemy's line, but mingles freely with them in the camp. There is nothing in his appearance to indicate who or what he is. To-day he is a civilian peddling fruits among the soldiers, or innocently driving a yoke of steers along the street or country road; to-morrow he is within the camp, dressed in their gay uniform, familiar with passwords and countersigns. Then he appears as a decrepit old woman, seeking a son who "run away to jine the solgers." In a few hours he is quietly resting or joking with the boys of his own regiment. When a spy is captured all military courtesies are set aside; he is not even allowed the honour of a court-martial; but without trial he is executed at once. It is of special interest, in view of the application to our subject, to notice the particular business of a spy. Just as his movements are unknown, so is his mission unknown. He hurries to and fro, gathering up such bits of information here and there as he deems important for the cause he represents. If he belongs to the Federal forces he appears clothed in the "butternut gray"; then by tactics of bravery and nerve he enters the Confederate gray lines. The slightest blunder is certain death. He takes a mental inventory of the whole situation, but in such a way as to attract the attention of no one. The strength of the fortifications, the size and number of the batteries, the commissary department, and the chances and probabilities of reinforcements. In a moment, under the cover of night, he fades out into the darkness and is gone. The budget of information is placed at the earliest possible moment into the war councils of his own army. Satan plays the rôle of a crafty spy; he has access, by some mysterious power, to the heart life of men. At no point of the game for immortal trophies is he so dangerous as when he can take advantage because of his secret knowledge of men's weaknesses and sins. Only a vicious degenerate can be tempted into all the crimes known to the docket of the Bible; few beings on this planet but are fortified at some point of character. They may be weak in many ways--but early training or environment have helped them to become strong in some particulars.