The foreman stooped down and pointed to the house.

"You see they have begun to put them on the outside of the walls of the house, but we had to have some more. You see that one edge of a clapboard is thin and the other edge is thick."

He pulled one of the clapboards from a bundle and showed David.

"The thick edges go over the thin edges, very much like shingles, and they keep the rain and the wind out. You know about shingles?"

David nodded doubtfully.

"I don't know whether I do or not."

"Well," the foreman said, "you ought to know about them. Those two men have just begun to shingle the piazza roof. If you can wait a few minutes, I'll take you up there. You aren't very busy this morning, are you?"

David smiled and shook his head.

The foreman smiled too.

"You wait right here, and I'll come and get you pretty soon."

So David waited, and while he was waiting he watched the men putting on clapboards.

They had begun at the top and had got about halfway down that side.

The side of the house was all covered with red stuff which looked something like cloth and something like thick paper. It was paper, and it rippled and waved in the wind.

The men were putting the clapboards on outside of that red paper.

A man had a pile of clapboards beside him, and he took one up and he lifted the edge of the one above, and he tucked the thin edge of the clapboard that he held in his hand under the edge that he had lifted; and he gave it little taps with his hammer until it was in the right place, and then he drove fine nails through the thick edge that he had lifted, and through the thin edge of the clapboard beneath, and into the wall of the house.

Then he took up another clapboard and put it close up to the one that he had just fastened, with its thin edge tucked under the thick edge of the one above.

The men put on clapboards very fast, and David was so interested in seeing them do it that he forgot that the foreman had not come back for him.

He had gone up nearer, so as to see just how the clapboards went on, when he heard the foreman's voice behind him.

"Well, Davie," said the foreman, "do you think you could put on clapboards as fast as that?"

David shook his head.

"No, I couldn't."

"Perhaps not. But come on, and we'll see what you can do with shingles."

And the foreman took David's small hand in his big one, and they went to where a ladder stood leaning against the edge of the piazza roof.

A little way below the edge of the roof there was a rough sort of a platform, made of two boards laid on some other boards that were nailed to the posts of the piazza and to long sticks which went up and down and had their ends resting on the ground.

This was what the carpenters called a staging or scaffolding, and when they got through their work, they would take it down.

"Now, Davie," said the foreman, "you take hold of the rungs and climb up. It's a pretty long stretch for little legs, but I'll hold you, and I won't let you fall. Don't look down. Look up."

So David took hold of a rung and stretched his leg as high as it would go, and he managed to get his foot on the first rung.

Then he pulled himself up and reached up with one hand and took hold of the next rung; and then he put his other hand up, and he stretched his leg up as high as it would go, and he stepped up another rung.

The rungs of a ladder are the little round sticks that go across that you put your feet on.

David climbed very slowly, and he was rather scared at first; but he felt the foreman's arm around him, and the foreman kept just behind him, so that he stopped being scared.

And he climbed a little faster, and he came to the platform.

"Now, what shall I do?" he asked.

"Now you hold your breath," the foreman said, "and I'll put you over on to the staging."

So Davie held his breath and one of the shingle men came and held him by the arms when the foreman had set him down upon the boards.

Then the foreman stepped upon the staging and put his arm around David again.

"There!" said the foreman. "You've climbed your first ladder. Now we'll see about the shingling."

There was a whole bundle of shingles on the staging, and another bundle that had been opened, and the shingle men had thrown a good many of these shingles up on the roof, so that they would be handy.

And David saw that there were three rows of shingles on already, and that a string was stretched tight across the last row; and the string was chalky-looking, and blue.

"They're just going to mark another row," the foreman said. "You watch."

Then one of the shingle men lifted the stretched string between his thumb and his forefinger, and he let it go, and it snapped down hard upon the shingles.

And they took the string away, and there was a blue line all along the row of shingles.

"What is that?" David asked.

"Chalk, Davie. They put chalk on the string by rubbing a lump of chalk on it. That line shows where the edge of the next row of shingles goes.

"And they lay the shingles on so that each crack in the row beneath is covered. The shingles are different widths, you see, and they can always find one that fits up close to the next one and covers a crack.

"If the cracks were not covered, the rain would get through and the roof would leak.

"Now let's see if you can lay shingles. Pick out one that you think will be right to cover the crack in the row beneath, and lay it down close up to the last one and with its thick edge to that blue line."

David was rather excited at the thought that he was to lay the shingles.

"Shall I?" he asked.

The foreman nodded, and he pointed to a shingle.

"Try that one."