“She’s got away from me! We’d all better jump!”

The car was on a steep down grade. Its speed was momentarily increasing, and it leaped and swayed wildly as it dashed down the hill. The motorman had hardly spoken before he made a leap from the front platform. The two boys saw his form sprawling on the road as he landed staggeringly. He was followed by the conductor of the car, who, more fortunate, managed to keep his feet after his jump.

All this happened with the rapidity of a swiftly moving motion picture film. The two boys found themselves alone.

When they had left Boston for High Towers, the suburban estate of Professor Chadwick, Jack’s famous father, the car had for some reason been almost empty. The last passenger, with the exception of themselves, had vacated it some moments before the brakes had failed to work and the vehicle had started on its mad career down the steep hill.

In a flash the runaway car had passed the two operatives who had deserted it in terror, and was dashing forward faster than ever toward the foot of the hill.

Jack and his chum started for the front platform. Jack had a vague idea that perhaps he could control the runaway car. Before them they could see, at the foot of the hill, a sharp curve of the tracks, and beyond the flashing water of Bluewater Cove, a small but deep inlet.

All this they had but a minute to realize. Hardly had the details of the scene impressed themselves on their minds—scarcely had Jack grasped the brake handle and twisted it desperately, before the car appeared to leap into the air like a thing instinct with life. There was an alarmed shout from both boys, which was echoed by a gray-haired man, who rushed from an odd-looking building, abutting on the water, at the same instant that the car left the tracks at the curve.

The lads had just time to glimpse his overalled figure and to note his alarm, when everything was blotted out as the car dashed into a clump of trees and was utterly demolished.

It was an hour or so later when Jack and his chum came back to their senses. Their eyes opened on a scene so strange to them that they were completely at a loss to account for their surroundings. Jack lay on a sort of cot-bed, while his returning senses showed him Tom reclining on a similar contrivance almost opposite him.

The room in which they were was an unceiled, unpapered apartment. The walls were of rough pine wood, and above them the naked rafters showed. In one corner was a stove, and in another a well-furnished set of book shelves. A library table which was littered with papers supported a reading lamp as well as what appeared to be models of different bits of machinery. Taken as a whole, the room appeared to be a section of a large wooden shed, paneled or partitioned off to serve as a living place.