How the explosive material was conveyed from Paris to Russia is a mystery which was never successfully traced by the police. The utmost care was taken at the frontiers to prevent the entrance of any suspicious substance. For a year or two even the tea that came on the backs of camels from China was carefully searched, while all travellers were closely examined, and all articles coming from Western Europe were almost pulled to pieces in the minuteness of the scrutiny. The explosive is said to have looked like golden syrup, and to have been sweet to the taste, though acrid in its after-effects. A drop or two let fall on a hot stove flashed up in a brilliant sheet of flame, though without smell or noise. [Illustration: THE ARREST OF A NIHILIST.] Among the conspirators, one of the most useful was Sophia Perovskya, the woman already named. She was young, of noble family, handsome, educated, and fascinating in manner. Her beauty and high connections gave her opportunities which none of her fellow-conspirators enjoyed, and by her influence over men of rank and position she was enabled to learn many of the secrets of the court and to become familiar with all the precautions taken by the police to insure the safety of the czar. There was another woman in the plot, a Jewish girl named Hesse Helfman. Eight men constituted the remainder of the party. The fatal day came in March, 1881. On the morning of the 12th Melikoff, minister of the interior, told the czar that a man connected with the railroad explosion had just been arrested, on whose person were found papers indicating a new plot. He earnestly entreated Alexander to avoid exposing himself. On the next morning the czar went early to mass, and subsequently accompanied his brother, the Grand Duke Michael, to inspect his body-guard. Sophia Perovskya had been apprised of these intended movements, and informed the chief conspirators, who at once determined that the deed should be done that day. The lover of Hesse Helfman had been arrested and had at once shot himself. Papers of an incriminating character had been found in her house, and it was feared that further delay might frustrate the plot, so that the purpose of waiting until the czar and his son might be slain together was abandoned. It was not known which street the czar would take. If he took the one, the mine was to be exploded; if the other, the bombs were to be thrown.