It seems to me that I, who know the secrets of the sandalwood box, have no right to give the explanation of this suppression before the hour at which Theophrastus learnt it himself, from a quite commonplace observation which the Commissary of Police, M. Mifroid, an earnest student of Logic from his earliest years, made to him in the Catacombs of Paris. At the same time, it is only fair to say that all the points in the problem are already in the possession of the reader, who can solve it himself, if indeed he has not already done so, without further delay. Theophrastus then, in a state of prostration, walked down the side-line, arrived at the bifurcation, examined the switch, thrust back the lever which he had thrust over, locked the padlock, and carried away, once and for all, the key which had been so carelessly left in it a few days before. He performed this action because he felt that it was only right; and he restored the switch to its place, because he felt that his reason could not stand another disappearance of the express. Still melancholy, he reached the deserted station A. All the rest of the staff was absent on the search for the express; only the signal-man was on the look-out. Theophrastus questioned the signal-man, who could only say, as he pointed to the red arm of the signal: "_The express is signalled, but it does not come!_" "Was it really signalled from the last station?" said Theophrastus. "Yes, sir, the station-master and all the staff of the last station saw the express go through it. They telegraphed it to us. Besides, sir, look at my little red arm! Look at my little red arm! And it is quite impossible that there should have been a wreck between the last station and this one. There is no bridge, sir, no viaduct, no works of art. Besides, just now I climbed to the top of that ladder against the big tank there. From it you can see the whole line right to the other station. I saw our people down the line, gesticulating, but I did not see the express!" "Strange--very strange," said Theophrastus mournfully. "Strange isn't the word for it! Look at my little red arm!" "Inexplicable!" said Theophrastus gloomily. "The most inexplicable thing in the world!" cried the signal-man. "Not so: there is one thing even more inexplicable than an express which disappears with its engine and passengers without anyone being able to tell what has become of it," said Theophrastus in the same gloomy tone. "What on earth's that?" said the signal-man, opening his astonished eyes wider than ever. "Why, a railway-carriage without an engine which suddenly appears without one's being able to tell where it comes from." "What?" cried the signal-man. "And which disappeared as suddenly as it appeared... You haven't by any chance seen a railway-carriage with a man looking out of the window pass this way?"