The silence was tense and taut, and broken only by the heavy breathing of the injured engineer.

“What is the man doing?” said the captain impatiently at length.

“It takes even shore doctors time to give a correct diagnosis in some cases, sir,” ventured Jack gravely. “I suppose he is considering the conditions.”

“Absent treatment at three hundred miles,” muttered the captain. “Ready, I begin to believe that this is a crack-brained bit of business, after all.”

“Wait a minute,” warned Jack, holding up his hand to command attention, “here is something coming now!”

His pencil flew over the pad and then stopped while he flashed back:

“Thanks, that’s all for now. I’ll cut in again when we are ready for the next step.”

He turned to the captain and read slowly from his pad the doctor’s directions for treating the injury.

“He says that, from your description, there are no bones broken. The arm is merely crushed,” said the boy; and then, bit by bit, he read off the far-distant surgeon’s directions for treating the injured member. As he read, the captain and his assistant amateur surgeons plied dressings and antiseptics with diligent care.

At last the doctor of the Parisian said that he had no more advice to give that night, but flashed a prescription for a soothing draught to be compounded from the ship’s medicine chest.