To one unfamiliar with the resources and organization of a great detective system it is incomprehensible how continuous "shadowing" day after day and week after week, through thousands of miles of journeying, can be accomplished. The matter is made none the simpler when you know that there must be a change of "shadows" every day. However adroit the detective, his continued presence in a locality would soon arouse suspicion. The daily change of "shadows" is easy when the man under watch remains in one place; for then it is only necessary to send a new "shadow" from the central office early each morning to replace the one who "put the man to bed" the night before. But it is very different when the subject is constantly traveling about on boats or railways, and perhaps sleeping in a different town each night. Without the network of agencies, including large and small bureaus, that the Pinkertons have gradually established all over the United States, the "shadowing" of a man in rapid flight would be impossible. As it is, nothing is easier. Schwartz, for instance, spent several days in Buffalo, where his actions were reported hour by hour until he bought his ticket for Philadelphia. As he took the train a fresh "shadow" took it too, securing a section in the same sleeping-car with him, and taking his meals at the same time Schwartz took his, either in the dining-car or at stations. No sooner had the train left the station than the Pinkerton representative in Buffalo reported by cipher-despatch to the bureau in Philadelphia, whither Schwartz was going. The exact form of the despatch, which well illustrates a system in constant use in the Pinkerton bureaus, was as follows: "R. J. LINDEN, "441 CHESTNUT STREET, "PHILADELPHIA, PA. "Anxious shoes sucker Brown marbles man other dropping eight arrives put grand fifty marbles articles along or derby coat ship very tan seer wearing these have and is ribbon ink dust central Tuesday for dust to rice hat and paper vest yellow ink get must jewelry morning depot on. "D. ROBERTSON." In despatches of this sort important information regarding criminals is constantly flashing over the wires, with no danger of any "leak."