These troops remained on active service until the 21st of April, when it was considered advisable to release all from duty with the exception of the 50th, 51st, 52nd, 60th and Beanharnois Battalions, and the two troops of cavalry originally placed on the south-eastern frontier, who remained on duty until the 29th of April, when they were also withdrawn. The Government was confident of the fact that the services of the volunteers would be cheerfully and promptly given whenever they would again be called upon, and in relieving them from duty, thanked them warmly for their service, and reminded them that it might be necessary to rally again to the colors almost any day, and to be ready to respond to the call. CHAPTER III. GEN. O'NEIL AGAIN INVADES CANADA--A RAID MADE FROM VERMONT PROMPTLY REPULSED BY A HANDFUL OF CANADIANS. About the middle of May orders went forth from Gen. O'Neil for the Fenian forces to again take the field, and a week later they began to assemble in the border cities, towns and villages of the United States, ready for another campaign against Canada. The rallying points were the same as those designated in Gen. Sweeny's plan of campaign in 1866. Gen. O'Neil seems to have considered that his chances of success would be better on the eastern frontier than by again attempting the invasion of the Niagara District, although his plan was to muster a strong force in Buffalo, as before, and, if opportunity offered, and he was successful in the east, to again attempt the passage of the Niagara. Consequently he gave his personal attention to the troops that were gathering on the Northern New York and Vermont frontiers, and directed the mobilization of the divisions at Malone and St. Albans, with the intention of following out Sweeny's old programme of conquest, while several officers of experience would lead in the attacks on other points.