Mr. Lincoln reached Philadelphia on the afternoon of the 21st. The detective had arrived in the morning, and improved the interval to impress and enlist Mr. Felton. In the evening he got Mr. Judd and Mr. Felton into his room at the St. Louis Hotel, and told them all he had learned. Mr. Judd was very much startled, and was sure that it would be extremely imprudent for Mr. Lincoln to pass through Baltimore in open daylight, according to the published programme. But he thought the detective ought to see the President himself; and, as it was wearing toward nine o'clock, there was no time to lose. It was agreed that the part taken by the detective and Mr. Felton should be kept secret from every one but the President. Mr. Sanford, president of the American Telegraph Company, had also been co-operating in the business, and the same stipulation was made with regard to him. Mr. Judd went to his own room at the Continental, and the detective followed. The crowd in the hotel was very dense, and it took some time to get a message to Mr. Lincoln. But it finally reached him, and he responded in person. Mr. Judd introduced the detective; and the latter told his story again. Mr. Judd and the detective wanted Mr. Lincoln to leave for Washington that night. This he flatly refused to do. He had engagements with the people, he said, to raise a flag over Independence Hall in the morning, and to exhibit himself at Harrisburg in the afternoon,--and these engagements he would not break in any event. But he would raise the flag, go to Harrisburg, get away quietly in the evening, and permit himself to be carried to Washington in the way they thought best. Even this, however, he conceded with great reluctance. He condescended to cross-examine the detective on some parts of his narrative; but at no time did he seem in the least degree alarmed. He was earnestly requested not to communicate the change of plan to any member of his party except Mr. Judd, nor permit even a suspicion of it to cross the mind of another. In the mean time, Mr. Seward had also discovered the conspiracy, and despatched his son to Philadelphia to warn the President-elect of the terrible snare into whose meshes he was about to run. Mr. Lincoln turned him over to Judd, and Judd told him they already knew about it. He went away with just enough information to enable his father to anticipate the exact moment of Mr. Lincoln's surreptitious arrival in Washington.