Through the rest of that day and the next the money had poured in, mostly in great sums from the banks and big business houses of the city who realized that it was only by payment of this tribute that the metropolis could be saved from chaotic ruin. Later on, they reasoned, the Invisible Master could be hunted down and dealt with, but now the thing was to lift his menace from New York. Five millions was a great sum, but not in comparison with the daily loss the city's businesses were undergoing. By the next afternoon the five millions were ready, a compact mass of securities and highest-denomination bills. It had been placed in the specified small steel box, and given into the charge of Kingston, a representative of the city's government who was to place the money as requested. And since the Invisible Master had mockingly given full permission for any to attempt his capture who wished to, Wade and Grantham had worked out the scheme that held a slender chance of trapping the unseen criminal. With their two-score of armed men waiting behind them, Grantham explained the plan in the lowest of voices to Carton and Kingston. "Kingston and I will take the box in and place it on the boulder," he whispered, "and when we do so I'll stretch in a circle of yards around it this thread of wire, and connect it to this pocket-battery and bell. Kingston and I will wait with the money, behind the big oak, and Wade's men will lie in a circle all around the spot. "When the Invisible Master comes he'll make for the boulder, and must necessarily strike the stretched wire and ring the bell just before he reaches it. Then your men can rush in from all sides to enclose him in their circle, while Kingston and I will be there and armed to prevent the money from being taken by him. It's our one hope of catching him, for we'll never have this chance again, I think." The Trap Wade nodded. "We all understand the plan, Grantham. We'll wait for him if it takes until daylight." "I think he'll appear tonight," Grantham said. "I imagine he is rather anxious to get the money and have it all over with." "Well, good luck," whispered Wade, extending his hand, which the physicist grasped. Kingston too, a little nervously, shook hands with the officer, and then the two disappeared silently into the dark wall of the wood eastward.