“But I thought terra-cotta was lighter brown and smooth. They make little images out of terra-cotta,” insisted Dorothy.
“I’ve seen those,” agreed Margaret, “but I suppose there can be different qualities of terra-cotta just as there are different qualities of china.”
“This stuff is fireproof, any way,” explained Dorothy. “I remember now hearing Mother and the architect talking about it. And they said something about a ‘dead air space.’ That must mean the holes.”
“What’s dead air space for?” inquired Ethel Blue.
“I think it dries up the dampness, or keeps it out so that it doesn’t get into the house.”
“These are useful old blocks, then, even if they aren’t pretty,” decided Helen, patting the ugly pile.
Mr. Anderson strolled toward them again after giving various directions to his men.
“Just how is this tile used?” inquired Dorothy, as he seemed to be more at leisure now.
“We build a wall of this hollow tile,” he answered; “then we put the plaster right on to it. Do you see that the outside is rather rough? That is so the plaster will have something to take hold of. We mix it up of cement and lime and sand and put on three coats. The first one is mixed with hair, and mashed on hard so that it will stick and it is roughened so that the next coat will stick to it.”
“Is the next coat made of the same stuff?”