"A passenger train, before arriving at the head of a long, evenly graded declivity, had taken on three or four good trucks heavily laden. Owing to some carelessness in the coupling these wagons became detached on the very crest of the descent, and falling to the rear came almost to a halt. Not quite: sluggishly at first they began to move, and gathering impetus from sheer weight followed in the track of the proceeding train. Halfway down the declivity, the engine-driver discovered his loss and the danger that threatened him. Looking back, he saw in the distance the wagons weighted by the labor of men's hands drawing nearer with a speed that grew ever more formidable. His one chance, therefore, of avoiding a catastrophe was to put on pace in the hope of arriving at more level conditions before the impact took place. Yet he must still limit himself to a speed which enabled the train to keep to the rails on a certain sharp curve which lay ahead. That was the problem which the engine-driver set himself to solve: up to a certain point the more pace he could allow the greater his chance of safety, beyond that point a new danger arising out of pace lay ahead of him."
"He negotiated the curve with success, and had got so far ahead that when the wagons finally overtook him their impetus had been diminished by the more level conditions of the road, and the impact was but slight. Only the guard's van was smashed, and the guard himself rather badly disabled."
"And what happened afterwards to the guard and the engine-driver?" inquired his Majesty, much interested.
"The guard was pensioned for life: the engine-driver was promoted."
"Well, not exactly," replied the Professor; "the careless coupling was done by others, but the guard had the right, which he had not chosen to exercise, to refuse to accompany any train in which his van was not put last--so as to embrace the whole combination. At least, he had the technical right."
"I suppose he did not wish to give trouble," said the King meditatively.
"Very likely; for, of course, had he exercised his right the whole train would have been delayed by the extra shunting."
"And he in consequence a less acceptable servant to his employers."