“About twenty windows to the average house,” I murmured. “Two thousand dollars for——”

“Well, it won't cost a tenth of that when I'm having the parts turned out in quantities,” cried Hawkins, with considerable heat. “Why under the sun do you always try to throw a wet blanket over everything? Suppose it does cost two thousand dollars to equip a house with my crook-trap? If a man has ten thousand dollars' worth of silverware, he'll be willing enough to spend——”

I laughed. It wasn't meant for a nasty laugh at all—it was simply amusement at the inventor's emotionalism. But it riled Hawkins.

“Where the devil does the joke come in?” he thundered. “If I——”

“Hush!” I cried.

“I won't hush! I——”

“Two!” I counted. “Be quiet.”

Hawkins calmed down on the instant.

“Was—was it the bell?” he whispered.

Ding! Ding! Ding! Ding!