Over the top, and some two feet above the tank proper, the heavy cover was suspended by a weird system of pulleys and electric wires. To the under side of the cover was fastened a big glass sphere filled with white stuff. It was a remarkable contrivance. “There--that's simple, isn't it?” said Hawkins, with a happy smile. “It may be if you understand it.” “Why, just look here. See that big glass ball? That's full of marble dust--carbonate of lime, you know. The tank is filled with weak sulphuric acid. When the ball drops into the acid--what happens?” “You have a nasty job fishing it out again?” “Not at all. It smashes into flinders, the marble dust combines with the sulphuric acid, and forms a neutral liquid, bubbling with carbonic acid. Even you, Griggs, must know that carbonic acid gas will put out any fire, without damaging anything. There you are.” “I see. You smell fire, rush up here and knock that ball into the tank, and the house is flooded through the dots in your frieze. Remarkable!” “Oh, I don't even have to come up here,” smiled Hawkins. “See that?” “That” was a little strand of platinum wire in a niche in the wall. “That's just a test fuse, so that I can see that she's all in working order,” pursued the inventor, leaning his cigar against it. “There's half a dozen of them in every room in the house. As soon as the heat touches them, they melt and set off my electric release--and down drops the cover of the tank--ball and all. The ball breaks, the valve at the bottom opens automatically--and down goes the tank, full of extinguisher.” “Well, I must say it looks practical.” “It is!” asserted Hawkins. “Some night--if the night ever comes--when you see a roaring blaze in one of these rooms subdued in ten seconds by the gentle drizzle that comes out of that frieze, you will----” “Mr. Hawkins, sir,” interrupted Hawkins' butler at the door. “Well, William?” “Mrs. Hawkins, sir, she says as how your presence is desired down-stairs.” “Oh, all right,” said the inventor wearily. “I'll be down directly.” “No rest for the wicked,” he commented to me. “Come on, Griggs, we'll have to dance.” The festivity was in full swing when we descended. Mrs. Hawkins came over to us and remarked in low tones to her spouse: “Now just try to make yourself agreeable, Herbert. It's not nice for you to steal away and smoke.” “I'm not smoking.” “Mr. Griggs is.” “So I am,” I said, suddenly realizing the fact. “William, will you dispose of this, please?” “Now go right in, both of you,” Mrs. Hawkins began. Then she was called away. “Griggs!” muttered Hawkins, thoughtfully tapping his forehead. “Yes?” “What--what the deuce did I do with my cigar?” “I'm sure I don't know.” “But I had it up-stairs. We were both smoking.” “So you did,” I said. “The last I saw of it you leaned it against that fuse thing----” “Great Scott! That's what I did!” gasped the inventor, turning white. “Well, what of it?”