Her father listened. Only the usual sounds came to his ears. The washing of the waves along the sides, however, had a peculiar timbre. Then he noticed that the boat seemed to be checking a little in its speed. There was an odd, velvety quality in the checking, very much like the soft breaking effect felt when a motor boat runs into a patch of weed.
"Queer," said Morrison. "We'll ask the captain."
The two of them walked down the deck arm in arm until they came to the stair ladder leading up to the bridge. The gentle checking continued. The boat seemed to be gradually slowing up, though the engines throbbed on as before.
"What's the matter, captain?" asked Morrison.
His first mate answered:
"I've sent for the captain, sir. Our speed has fallen off three knots in the past five minutes."
The captain came hastily up on the bridge, buttoning up his coat as he came.
"What's the matter, Mr. Harrison?"
The first mate turned a worried face to him.
"Our speed has dropped off three knots in five minutes, sir, and seems to be still slackening. I thought it best to send for you."