He walked back, carefully examining every inch of the rail until he found what he sought. At one place by the side of the actual rail was a little red spot. It was no larger than a three-penny piece and it was, to all appearance, rust. But rust does not develop on a wooden sleeper and he found the counterpart of this spot, a trifle larger on the wood. Again he wetted his finger and was satisfied. For this was not rust, but a very common form of distemper employed by builders. He went back to the buffer and the sagging rail and climbed down the hole which was about six feet deep. He had noticed that a quantity of green stagnant water at the bottom of the hole advertised its age. Again he drew his hand along the water and examined his palm. It was green, but his strongest magnifying glass (and he had one of peculiarly high power) failed to reveal any sign of that florescence which forms on the surface of water and gives it its peculiar vivid green. Instead, he saw a number of irregular specks, which were undoubtedly crystals. “Which means,” said Michael to himself, “that Kate is an artist even if Fonso isn’t.” The green scum which had deceived him at first had been artificially created. Some chemical had been dissolved and had re-crystallised on the surface. He dug into the soft earth on the other side without securing any data as to when the hole had been made, but nearer the surface and on the rim, he saw the white tendrils of growing coltsfoot, which were still humid. One tentacle had been shaved away, but the plant had not yet begun to die, nor the exposed root to blacken. “This hole was dug on the night of the robbery,” said Michael, “and the earth was artistically removed. Kate would depend upon the railway officials not having bothered to inspect this bit of line.” As matter of fact, this was so. It was on private property, and after it left the edge of the railway land it ceased to be their responsibility. The buffer was also newly erected. He found this when he had dug down to its foundation. The wood was still dry and there were blades of grass and tiny fragments of plant in the earth beneath. He walked round the little pit and reached the rails on the opposite side. They were rusted as artistically as their fellows. The line twisted and curved across level country for a mile before it turned the shoulder of a hill and disappeared into a gorge, evidently excavated in the course of the working. Behind this was another chalk hole, and he gathered from an examination of the map, that along this further ridge ran a road. The abandoned cement works had been so built that they were not in view from the railway itself. Possibly the philanthropic purchaser had pulled down the one remaining smokestack on his occupation and the whitened buildings did not stand out against the chalky soil behind them. He had all the evidence he wanted before he had traversed one-half of the two miles which separated him from the chalk pits.