“It may not have been one of Ruth’s rings, to begin with,” reasoned Neale. “And, if it is, I don’t believe Hank had anything to do with taking it, though he may know who did. I’ve got to keep on the watch!”
His meditations were interrupted, as he sat on the deck of the boat, by hearing Hank cry:
“Lock! Lock!”
That meant the boat was approaching one of the devices by which canal craft are taken over hills. A canal is, of course, a stream on a level. It does not run like a river. In fact, it is just like a big ditch.
But as a canal winds over the country it comes to hills, and to get up or down these, two methods are employed. One is what is called an inclined plane.
The canal comes to the foot of a hill and stops. There a sort of big cradle is let down into the water, the boat is floated into the cradle, and then boat, cradle and all are pulled up over the hill on a sort of railroad track, a turbine water wheel usually furnishing the power. Once over the brow of the hill the cradle and boat slide down into the water again and the journey is resumed.
The other means of getting a canal boat over a hill is by means of a lock. When the waterway is stopped in its level progress by reaching a hill, a square place is excavated and lined with rocks so as to form a water-tight basin, the open end being closed by big, wooden gates.
The Bluebird was now approaching one of these locks, where it was to be raised from a low to a higher level. While Hank managed the mules, Neale steered the boat into the stone-lined basin. Then the big gates were closed behind the craft, and the mules, being unhitched, were sent forward to begin towing again when the boat should have been lifted.
“Now we can watch!” said Dot as she and Tess took their places at the railing. Going through canal locks was a novelty for them, as there were no locks near Milton, though the canal ran through the town.
Once the Bluebird was locked within the small stone-lined basin, water was admitted to it through gates at the other and higher end. These gates kept the body of water on the higher level from pouring into the lower part of the canal. Faster and faster the water rushed in as the lock keeper opened more valves in the big gates. The water foamed and hissed all around the boat.