A correspondent of the New York Tribune writing from Washington, says:

We may, perhaps, meet a man in a broad straw hat, and without his tale-telling shoulder-straps, riding slowly through the camp, looking intently at the men, and noting every item of their accommodations, and overhearing, without seeming to listen, every word of their much or little grumbling. Unless he happens to he personally known, few take notice of him, and the utmost of recognition he receives is from the wide-awake sentry, who demands his authority for passing through the lines. Yet if this man were to appear In all the gaudy paraphernalia with which the articles of war entitle him to bedeck himself, the musket of every sentry would be at the “present,” and the hand of every man and officer would visit his cap with respectful military salute—for this unostentatious man is an officer of high rank, on a quiet tour of observance. He may be a Brigadier General, or even a Major General, or it is not impossible that it is the now universally-trusted McClellan himself.