New York , Aug. 9.---The 15^th Massachusetts regiment, Col. Devens , arrived at 11 o’clock this morning, and took dinner at the spacious depot of the Norwich and Worcester line, which had been prepared for the occasion by Mr. E. S. Martin, the agent of the line.  They were afterwards transferred to transports and conveyed to Amboy, whence hey proceed on the route to Harper’s Ferry.  By some oversight, the car containing the whole seven days rations was left behind, occasioning some grousing among the men about breakfast time.