Down and down through the dim water he dived straight and true. Hardly had he disappeared from sight before great air-bubbles came up and broke on the surface, and a few seconds later wavering up from the depths came what seemed to be his lifeless body with staring, horrified eyes and open mouth.
As his white face showed above the surface, Will and Joe leaped in together, and in an instant had him out and on the raft again. In another minute the two boys were making good use of their knowledge of first aid, which they had learned as Boy Scouts. Working as they had never worked for merit badges, they laid Jud on the raft face down, with his arms above his head and his face turned a little to one side. Then, while Joe pulled his tongue out, Will, kneeling astride his body, pressed his open hands into the spaces on either side of his ribs. Then, alternately pressing and relaxing his weight as the water ran out of Jud's mouth and nose, Will began the artificial breathing at the rate of fifteen times a minute, while Joe rubbed with all his might the old trapper's legs and body toward the heart. At the end of a couple of minutes of this strenuous treatment Jud gave a gasp and at last opened his eyes. Half an hour later he was able to tell what had happened.
"I didn't get more than half-way down," he said weakly, "when a great greenish-yellow eel, five feet long an' big as my arm, came gliding toward me. I tried to pass it but in a second I felt its cold, clammy body pressin' against mine. Then came a flash, an' somethin' broke in my head, an' the next thing I knew I was up here with you chaps workin' over me."
Professor Ditson brought his hands together with a loud clap.
"That is what Dawson meant by saying the lake was guarded," he said. "What attacked Jud here was a gymnotus."
"An electric eel," explained the Professor. "The old priests must have brought them up from the lowlands, and they have thrived here in this warm water ever since. It carries an electric battery in the back of its head, and a big one can give a shock which will stun a strong man. Wait a moment," he went on, "and I'll show you every electric eel within a radius of fifty yards."
As he spoke he fumbled in his knapsack and pulled out a cylinder two feet long, wrapped in waxed paper, with a curious little clockwork attachment at one end.