In Christmas week of 1887, the Russian agents at Geneva, in Switzerland, reported the presence in that city of two revolutionary agents who seemed to have the closest relations with the committee of the discontents in London and Paris. They were shadowed for a time, but lost. In February they reappeared in Berlin. They were known to be in communication with the St. Petersburg Nihilists. Before facts enough had accumulated to justify their arrest they disappeared once more and were believed to have gone to the Russian capital. The facts were reported to the Czar, but he laughed at Chief Gresser of the capital police. [Illustration: THE NIHILISTS IN THE DOCK. 1. Risakoff. 2. Mikhaeloff. 3. Hessy Helfmann. 4. Kibaltchik. 5. Sophia Peroffskaja. 6. Jelaboff.] In solemnizing the requiem of the late Czar a public progress was made to the Cathedral, amid a dense throng of citizens, among whom were all the detectives that Chief Gresser could get together. In a small café in one of the side streets of the Morokaya two of the detectives ran across a couple of uniformed university students—in Russia the students have a peculiar costume—who were acting suspiciously. They were conversing in a most excited manner with a man dressed as a peasant. The trio were watched. At the café door they separated, but all three made by different routes for the Newsky Prospect, the chief drive of the capital and the one along which the Czar was to return. The peasant was lost by the detectives, but the other two were kept in sight, and the suspicions of the police were made all the more keen by the fact that the young men passed each other in the crowd several times with an elaborate appearance of not knowing each other. One of them had a law-book in his hand; the other had a traveling-bag over his shoulder. [Illustration: EXECUTION OF THE NIHILIST CONSPIRATORS.] A few moments before the Czar was to pass on his return from the Cathedral the students came together and whispered, and the two were immediately and quietly arrested. Their names were given as Andreieffsky and Petroff, university students, and this was proven to be the truth. A thrilling discovery was made, however, at once. The innocent-looking law-book was really a most dangerous infernal machine—sufficiently powerful not alone to kill everybody in the Czar’s carriage, but many in the crowd, and perhaps to have blown down some of the neighboring houses. The traveling-sack was full of dynamite bombs of the ordinary spherical pattern. [Illustration: Fig. 1. Interior. Fig. 2. Exterior. A. Glass Tube. B. Fulminate. C. Bullets. D. Dynamite.] I reproduce here a diagram of the book-bomb from the excellent account of the attempted assassination given by the New York _World_ a few days after it occurred.