The ground upon which the liberal compensation usually granted in salvage cases rests, is three-fold. First: A marine peril. Second: Voluntary service. Third: Success.

It is necessary that the property be saved from extraordinary danger. This danger or distress must have been real, or appeared to be so in the exercise of a sound discretion, though it need not have been immediate, or certainly destructive. (h) 1 If the master, with his crew, might have saved it, the interference of the salvors would be presumed to be unnecessary ; (i) they may, however, still make out their claim by proof that the master would not have saved it. It would be equally a salvage service whether it were rendered at sea, or upon property wrecked at sea but then on the land. (j) And a salvage service may be rendered either by seamen or by landsmen. (k)