"You are Spencer Vance."

The young man could not conceal an expression of extreme astonishment.

"Who told you my name was Spencer Vance?"

"It matters not, but take heed; do not go out on the sea to-night."

"I tell you I must! I will go, but you must tell me what you know of Spencer Vance."

"You are a revenue detective; you are in the employ of the Government; you have been betrayed, and to-night you are to be silenced if you go out on the yacht!"

"Do the men on the yacht know who I am?"

"They do not know your name, but they suspect you are a Government detective, and they have determined to put you out of the way; to-night they will do the deed if you go."

"Someone must have told them I was a Government officer."

"Yes; someone told them."