Death in the Tunnel by Miles Burton

direction only, as a lantern does. And a powerful electric lamp, such as these appear to have been, would be visible a lot farther than an ordinary railway lantern. As a guess, after seeing the conditions in that infernal tunnel, I should think that to be seen at a distance of half a mile, the lamps must have been of at least a hundred candle-power each. And that raises an even bigger problem than how the chap got into the tunnel.”
    â€œWell, let’s have it,” said Arnold. “One problem more or less won’t make much difference.”
    â€œHere you are, then. Electric lamps don’t produce light of themselves. They have to be supplied with current. Where did the chap get his current from? There’s no electric supply main running through the tunnel, you know.”
    â€œI’m well aware of that. The man carried a battery with him, of course. Just as we carry batteries in our torches.”
    Merrion shook his head. “The lamps in our torches aren’t a hundred candle-power, or anything like it. Being quite small, they take very little current, and a small battery is enough to supply it. But to supply current for these lamps nothing lighter than a fair-sized motor-car battery would do. Have you ever tried carrying one of them about? They’re devilish heavy, I can tell you. It would be a terrific feat to carry one into the middle of the tunnel and out again.
    â€œYet, by using ordinary household bulbs, this man deliberately saddled himself with the necessity for such a battery. Why did he use that kind of lamp? A couple of large-sized torches, or even one, with a movable red and green screen fitted to it, would have done just as well. By means of a lens and reflector a torch is made to give as much light as one of these lamps. But this is done by concentrating the light in one direction only. The only possible reason for using ordinary lamps, with their much greater expenditure of current, would be to obtain the advantage of the light showing all round. But, in heaven’s name, why should this chap have wanted that?”
    â€œI haven’t the least idea,” Arnold replied, shrugging his shoulders. “Your imagination is leading you away from the point. What reason the chap may have had for using lamps instead of torches can’t possibly matter. Here are the lamps, or what’s left of them. That’s sufficient proof to me that the chap used them, and that he had with him a source of current from which to light them up. And when he’d done with them, he chucked them aside in the tunnel. So much is plain enough.”
    Merrion picked up the bits of flexible cord and examined them intently. “Our friend’s proceedings strike me as bordering on the insane,” he said. “He burdens himself with a cumbrous battery, when a far lighter torch would have served him equally well. When he has finished with his apparatus, he throws away the lightest part, and keeps the heaviest. For he certainly didn’t leave the battery in the tunnel, or we should have found it. And he doesn’t just disconnect his flexible. He breaks it violently, as you can see for yourself if you look at it.”
    â€œI’m not interested in details like that,” said Arnold impatiently. “Do look at the matter sensibly, there’s a good chap. We know now that Prentice and Haynes weren’t imagining things when they saw those lights. Therefore a man had entered the tunnel with the definite object of slowing down the train. Why should he want to slow down the train? Tell me that.”
    â€œSo that he could board it, I suppose,” Merrion replied. “Look here, Arnold, have you ever climbed into an English railway carriage when it wasn’t standing at a platform?”
    â€œYes, I climbed into that first-class coach when it was standing in the siding at Stourford yesterday morning.”
    â€œWould you have liked to have done so with a battery