Spy to be hung.
--A letter from Fort Gaines, in Mobile harbor, dated the 8th inst., gives an account of the sentence of death having been passed upon a spy. He is a Captain of the 23d New York regiment, came through our lines at Richmond, Va., and has been spying ever since. He has visited Charleston, Savannah, Chattanooga, and this town, as also nearly every prominent point in the Confederacy. His last visit was to Mobile, where his money gave out, and he then endeavored to procure a position as substitute in one of the companies stationed at Fort Gaines, but the Colonel refused to accept him, not believing him above the conscription age. He then went over to Fort, Morgan, where he was taken as a substitute; about two weeks after, he left his post and started for the Yankees. Pursuit was immediately made, and our men succeeded in catching him about six miles from the fort. Upon his person was found a plan of Forts Gaines and Morgan, giving the strength of the forts and the number and size of the guns. He was court-martialed and sentenced to death. The sentence has been approved by the President and he will be shot on the 28th inst. After his capture he confessed being a spy, and gave the number of his regiment. The fact of this man being able to go at large for the length of time he evidently was, admonishes us to be careful of all strangers who may come into our lines. If proper vigilance was secured, dozens of spies would be detected giving all the information that leads to our reverses.