Washington, Sept. 8, 1861. The Seventh Michigan, ono of the finest regiments in appearance in the service, arrived yesterday. It is composcd of young mon frora the pine lumber distriets of Northern Michigan, who average in height about fivo feet oight, and in wcight onc hundrcd and sixty pouuds. Thoy are commauded by Col. Grosvenor, a distinguished lawyer, and one of tho Taoit energetic men in the service. ïhat they will givo a good account of themselvcs, none acquaiuted with thcir hardihood and laborious training can doubt. They are encamped upon Meridian Hill, but it is understood will soon cross the Potomac. Soldiers soon learn to be reckless. - The encampment of tho Second Michi gan is in the vieinity of Munson's Ilill. Their pickets and tlioso of the rebels aro within talking distance. I was told that they frequently exchanged epitheta, the one daring tho other to show himself, neithcr losing any opportunity that offered to piek the other off by a well-directed bullet. My informant assured me, with a gusto that I could not appreciato, that it was tho greatest fuu in the world to go to a certain point in the neighborhood, whence be could see and bo seen by the rebels, and thcre listen to tho whizzing of their bullets in the bushes and among tho troes surrounding him. "But," I inquired, "do they not lcill some of your men?" "Oh I" replied he, ''they oceasionally take down a picket, but we are more than even with them." A few nighta ago tbree of our men stole out of our camp for tho purposo of getting a few roasting ears from tho corn-field in which tho rebel picket is stationed. Two were to watch, while the third gathercd tho corn. Just as he commonccd picking the ears a bullet whizzcd across bis thighs, just grazing the skin. Uttering in a loud voicc tho words " I am shot,'' he turned, drew bis gun to his shoulder, and taking delibérate aim, lodged tho bullet in tho heart of his enemy, who feil dead without a groan. These are 6orae of the sports of camp life. How do you rclish them.