The ultimatum was duly presented, and a copy appeared in the leading newspapers of the two republics. People began to ask, "What is the _Olive Branch_? And what is her nationality?" Then someone suggested that the message was the work of either a practical joker or a lunatic, and the heads of the two republics treated the message with contempt. Not for one moment did anyone connect the _Olive Branch_ with the ex-Brazilian cruiser that had committed an outrage upon the German flag off the port of Pernambuco. The very idea of a vessel being able to travel from that port to Valparaiso--a distance of 4,600 miles--in less than four days never entered into anyone's head, and when the journal _El Mundo_ broadly hinted that it was a ruse on the part of the Peruvians to frighten the antagonists, the Chilian fleet immediately put to sea. This news was communicated to the _Olive Branch_ from Antofagasta, followed by the information that the Peruvian fleet had steamed out of Callao, bound south. "Now we'll have them!" exclaimed Captain Brookes. "We'll get in touch with the Chilian vessels first, then pass them hull down so as to get between the two fleets. This done I hold them in the hollow of my hand." Unfortunately for Captain Brookes his plans were doomed to failure. The fleet of the Southern Republic was sighted and passed as arranged, but in the interval the Peruvian squadron had altered its course and was steaming for Iquique. "There they are," announced Captain Brookes, late one afternoon, pointing to a dense haze that obscured the otherwise clear horizon. "Not much mistake about that, sir," assented Tregarthen. "If those vessels are not burning Lota coal, I'm a Dutchman!" "It's too late to do anything much to-day," added the captain. "I'll give them a dose of Z-rays, and during the night we'll slow down and hang on their flanks. To-morrow we'll press the business." Throughout the night the Peruvian fleet, unable to use searchlights and night-sights, pounded along, keeping an erratic compassless course towards Iquique. Unable to explain the cause of the sudden failure of their electrical gear, the officers and men were in a state of nervous tension, expecting every moment to find the Chilian fleet at their heels. Just before daybreak the _Olive Branch_, to avoid being influenced by the Z-rays that permeated the fleet, put her helm hard over in order to allow the fugitives to gain a few miles. As she did so a violent explosion shook the ship from stem to stern, and a huge column of water sprang up from alongside her starboard quarter. "A mine, by Jove!" exclaimed Gerald. He was right. The Peruvians had strewn the sea with mines as they fled for shelter, and, on turning, the _Olive Branch's_ starboard propellers had struck the dangerous weapon.