So down they went. John pounded the nail into a tree, and pulled it out again, till he had made quite a hole. Then he made a little wooden spout for the sap to run in, and hung his pint kettle upon it.
"By to-morrow," said he, "that kettle ought to be full of sweet sap, a lot nicer than any honey the bees ever thought of."
"O," cried Tim, "I thought it would be full of maple sugar, all ready to eat!"
"You didn't suppose that maple sugar ran out of a tree all ready made, did you, Tim?" said John. "You don't know much. You ought to study trees and things. You see the sap runs out when you tap the tree. Then you build a fire and boil it down. When it's cool, there's your sugar, sir."
"We'll boil it down to-morrow," said Tim.
But it was a long time till to-morrow! Tim and John went to bed early and got up early. As soon as school was done they ran to the wood-lot to boil the sap down. But there was not a drop in the little kettle! Tim almost cried. "What a stingy tree!" he said.
Miss Smith, who was gathering autumn leaves in the woods, came along while they were talking. "Are you tapping for maple sap?" she asked. "This is the wrong season of the year, John, you know."
John didn't know.
"The spring is the time, when the sap runs up. And when you want to make maple sugar, you must tap a maple-tree. This is a birch! You ought to study about trees, John."