Petty larceny detectives from Baltimore, Philadelphia, and New York.—Rebel War Clerk’s Diary.

AUGUST 8th.—For some time past (but since the battle at Manassas) quite a number of Northern and Baltimore policemen have made their appearance in Richmond. Some of these, if not indeed all of them, have been employed by Gen. Winder. These men, by their own confessions, have been heretofore in Baltimore, Philadelphia, and New York, merely petty larceny detectives, dwelling in bar-rooms, ten-pin alleys, and such places. How can they detect political offenders, when they are too ignorant to comprehend what constitutes a political offense? They are illiterate men, of low instincts and desperate characters. But their low cunning will serve them here among unsuspecting men. They will, if necessary, give information to the enemy themselves, for the purpose of convincing the authorities that a detective police is indispensable; and it is probable a number of them will be, all the time, on the pay-rolls of Lincoln.