"Why, if this happens to be a cold winter, every pole in sight may be broke off by the ice. If a skipper has put down fresh poles just before winter, he can find his bed pretty easy when spring comes."
"How?" asked Alec in amazement. "How can he ever tell where his grounds are if his stakes are gone?"
"Well, they won't be gone altogether. Just the tops are broke off. At low tide there'll be some stumps sticking up. A skipper just sails out and gets the range of his beds and then hunts for his stakes till he finds them. Then he puts down new stakes."
"But how can he ever get his range, as you call it?"
"Oh! He knows his landmarks. You see Egg Island Light over there, and just behind it that tall clump of trees? Well, if we had an oyster-bed right here, that light and those trees would always be in a line when we are over our bed. Now if he had some landmarks in this other direction, too, a skipper could always tell when he was right on this spot, for he'd have to have both sets of landmarks in line."
"Why, that's nothing but triangulation," said Alec. "We studied that in school."
"I don't know what they call it in school, but that's the way a skipper finds an oyster-bed when his stakes is gone."
"What I don't understand," questioned Alec, "is why the ice doesn't take the stakes away altogether, instead of just breaking off the branches at the tops of the stakes."
"Lord bless you, son! You couldn't pull them stakes up with a derrick."
"Why not?"