Tregarthen is initiated into the secrets of the _Olive Branch_, including that of the deadly ZZ-rays--an irresistible charge of electricity whereby the destruction of a hostile ship can be made at will. Captain Brookes also explains that by the power at his command he hopes to make war so terrible that no nation will venture to declare war; thus universal peace will be assured. During the voyage south a German "tramp" is boarded for the recovery of some plans which had been stolen by a deserter, and for this action the _Olive Branch_ is branded as a pirate. Hostilities break out between Chili and Peru, and Captain Brookes determines to intervene. The _Olive Branch_ is damaged by a mine, and while undergoing repairs is trapped by a British squadron. Captain Brookes is handicapped by a vow never to fire on a British vessel. By the aid of the Z-rays, however, the _Olive Branch_ escapes, though not without sustaining injury. The vessel puts into a creek in the Patagonian coast for repairs. A number of blacks which are encountered at first appear friendly, but afterwards prove treacherous, and to cower them Captain Brookes utterly destroys, by means of the ZZ-rays, a huge rock regarded by the natives as the home of their god of war. Later the captain receives a message which, without disclosing particulars, he tells Tregarthen is to the utmost urgency, and involves immediate action. [Illustration: chapter XIX] CHAPTER XIX GERALD'S PROMOTION A WEEK later the _Olive Branch_ was once more ploughing the waters of the North Atlantic. Since leaving Desolation Inlet her battered appearance had undergone a great change. The bridge and chart-house had been replaced, but the task of renewing the automatic steering-gear was, for the time being, beyond the resources of the ship. Thus, day and night, one of the quartermasters and two assistants had to take their places at the wheel, instead of merely keeping a sharp look-out as the _Olive Branch_, like an intelligent human being, pursued an unswerving course. By this time the identity of the hitherto mysterious _Olive Branch_ had become common property, and the principal European nations had agreed that she was not to be ignored as a fighting machine. Incidentally, Gerald's report to the British Admiralty had served a useful purpose, for, unknown to Captain Brookes and his officers, code messages had been dispatched to the numerous ships flying the White Ensign on the high seas, ordering them to abstain from hindering or molesting the cruiser, unless the latter were caught in the act of committing an outrage on British shipping. No doubt Captain Brookes's magnanimous forbearance when he ran the gauntlet from Talcahuano Harbour had much to do with this decision, but, being ignorant of it, the captain of the _Olive Branch_ still took precautions to avoid coming into contact with a British man-of-war.