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,
