A Circle of red light gleaming out of the darkness like a drop of ghost's blood—or a bright, green eye, as of “a little yellow god.” These are the two signs that the enginedriver, peering round the hood of his rocking cabin, watches for keenly as his long train whirls on over the miles of iron track that run along the skirts of night.

Is it the green orb showing? Then onward it is, with a little less steam, a little less tension. The end of the home run is in sight for the driver, with the mouthwatering prospect of a bacon-and-eggs supper, a pipe of peace and a peep at the youngsters in bed. Back in the carriages the passengers yawn and prepare their luggage. All is well.

But is it the red light showing? Shut off steam, put on the brakes, slow down to a stop. What's wrong? Well, whatever has happened, the green light will show up soon, as if the little god has suddenly devoured the owner of the red eye, and is sitting up on the signal-post there, winking. No danger so long as the train stays still. That bright red eye is a word of command. The stationary engine belches steam like an angry dragon, but there is a greater power in its path, and it must stay still. A passenger who stops a train without good reason does so at risk of a heavy penalty, but that red light is exempt. It is the first and the last word.