Bertie had no idea what a bulkhead was, or where it could be found; but as the man pointed to the other side of the cellar, away he ran to find it.
Now the mystery was explained. Just under the place where his father had told him the kitchen was to be, there was a kind of road leading down into the cellar, and while Bertie was waiting, he heard Tom's voice calling to Buck to "gee, back, back, sir."
There was no place to turn around in the cellar so the oxen had to back the cart with its wide wheels down the steep road. As soon as they were in the right place, the Irishmen came and helped Tom load the cart full, which was very quickly done; and then Buck and Bright pulled away with all their strength till they were out on the level ground. This time they did not carry the gravel far, and so were ready to back down again in a very few minutes.
"What makes this dirt look so different from that?" inquired Bertie, pointing to a pile of rich black loam.
"The top of the ground is always richer earth," answered Jim, who was just going by, driving Star and Spot. "Underneath it is only gravel."
"What is gravel good for?"
"It will do very well to put on roads, or to fill up with. I heard your father say he was going to make avenues and terraces with this."
"What are avenues?"
"Roads, drive-ways."
"What are terraces?"