These electrical contrivances are familiar to all boys. A small electric lamp is set in the end of a hollow tube of tin, and about the lamp is a reflector. Dry electrical batteries are put in the tin tube, and by means of a push button the circuit is closed, illuminating the lamp, which gives a brilliant glow. Tom had a special kind of lamp, with tungsten filaments, which gave a very powerful light, and with batteries designed to last a long time. A clip on the spring controlling the push button made it so that the lamp could be made to give a steady glow. Thus they were well prepared for exploring the tunnel.
It took some little time to get the flash lamps ready, and when they were all charged and they had eaten, they went back to the opening to see if the air had cleared. Tom tested it by dropping a match down, and, to his delight it burned with a clear flame.
"It's all right!" he exclaimed. "The air is pure. Now to see where we will bring up. Come on, everybody."
"Jest one minute, Massa Tom," begged Eradicate, as the young inventor was about to descend the steps, which even the brightness of his lamp did not disclose the end. "Is yo' gwine down dar, Massa Tom?"
"Certainly, Rad."
