Elmer suddenly remembered that Professor had appointed that night for the rehearsal. "Oh, yes!" said Bo. "By the way, it's to be at our house and I had forgotten all about it. Mamma has invited some of the neighbors to spend the evening and act as audience, so that the timid ones will get used to playing before strangers. Here we are. The gate is open and there's a sleigh at the barn, I shouldn't wonder if Professor had come already. Elmer, do hurry back; don't dress as if it were the real concert."