Purt sat with his back to the twins, and was explaining to the girl beside him that he did not mind riding backward at all. Bobby was still on the ground, and as Dora and Dorothy looked down at her they saw the mischievous one suddenly reach up her thumb and finger and pick at a little frayed place upon the edge of Purt's beautiful sash.
The thing was knitted loosely of some kind of mercerized cotton, and when Bobby seized the end of a broken strand the sash began to unravel with marvelous rapidity. She grinned up at the twins delightedly, and continued to pull on the thread.
"All aboard, young folks!" cried Mr. Purcell. "You ready forward, there, Mr. Chetwood?"
"All right," returned Chet, tripping his self-starter.
Mr. Purcell stooped to crank up his big machine. Bobby, her eyes dancing, also stooped beside the front wheel for a moment, and then whisked into her seat, facing Purt Sweet. But the twins saw what she had done. She had fastened the end of the crimson thread to the head of a bolt upon the wheelbox.
"All right, Bennie!" said Mr. Purcell, stepping back and waving his hand. The big machine began to tremble and shake, and then they pulled out behind the Belding car. There was a lot of noise, and laughter, and fun; but nobody seemed so hilarious as Clara Hargrew and the Lockwood twins.
"Can't you keep your eyes off Purt, Bobby?" demanded the girl sitting next to the Sweet boy. "What's the matter with him?"
"No—nothing!" chortled Bobby, stuffing her handkerchief into her mouth.
But she was watching that red thread shooting down to the wheel and winding around and around the box, faster and faster as the big machine got under way. By the time the auto turned into Market Street a great ball of the red worsted, or whatever it was, had formed on the inside of the wheel, and the perfectly unconscious Prettyman Sweet was fast losing his beautiful crimson sash.
The knitted part of the sash overlaid a belt of canvas which really did the service of holding up the exquisite's trousers. But fast, fast indeed, the red thread was running out.