Our younger readers may not understand how a conversation is carried on between ships at sea, several miles distant from each other. There are ten small signal flags representing the nine digits and the zero. Any number can of course be formed of these figures. Every ship is provided with a number, which if it consists of two figures is represented by two flags, hoisted together; three figures, three flags; and so on.
The signal book also contains a great number of questions and answers, such as, "What ship is that?" "Where bound?" "All well." "Short of water," &c. Each sentence has its invariable number, which may be indicated by the signal flags. If one vessel shows the number 124, the captain of the ship signalized would find this number in his signal book; and against it would be printed the question or answer.
Somers was not disposed to reply to the question of Pillgrim; and as he did not do so, the traitor immediately took the alarm. The Ben Ledi went about, and made off to the eastward under full steam. The Firefly was all ready to follow, and then commenced a most exciting chase. It was useless to waste shot at that distance, and Somers confined his attention to the speed of his vessel. For three hours the pursuit was continued, without any perceptible decrease of the distance between the two steamers.
But it was soon discovered that Pillgrim was gradually wearing round. Somers perceived his intention, but it was not prudent to attempt to cut him off all at once, by taking the arc of a smaller circle; but he worked his ship slowly round; and when both vessels were headed to the west, he had gained a mile. Pillgrim had evidently made up his mind to go into Wilmington at any risk, though under ordinary circumstances the more prudent course would have been for him to continue at sea, where a dark night or a fog might have enabled him to elude his pursuer. Somers concluded, therefore, that the Ben Ledi was short of coal, for his own supply was nearly exhausted.
The furnaces of the Firefly were now worked to their utmost capacity, and every expedient to make steam was resorted to by the excited engineers and firemen. There was a stiff breeze from the south-west, and both vessels had crowded on every stitch of canvas that could be spread. It had already been demonstrated that there was no appreciable difference in the speed of the two steamers, and the result of the chase was to depend entirely upon the management of each.
When the two vessels had come about so as to make a fair wind, the Firefly had been the first to spread her canvas, and the superior discipline of her crew was thus made apparent. A slight advantage had thus been gained, and it was certain that "the balance of power" lay in the sails. At meridian an observation was obtained, and the position of the ship was accurately laid down on the chart. The latitude was 33° 59' 7"; the longitude 76° 29' 23". To make the Swash Channel, which was covered by the guns of Fort Fisher, the Ben Ledi would have laid a course about half a point south of west; but her present course was west-south-west. Somers, after examining his chart, had some doubts whether she was going into Wilmington.
Tom Longstone had the deck during the afternoon watch. He was a veteran seaman, and his experience had made him more familiar with canvas than with steam. With the most anxious solicitude he watched the sails during the afternoon, and under his skilful directions they were kept perfectly trimmed. On that momentous occasion everything was reduced down to the finest point, as well in the handling of the engine as the tacks, sheets, and halliards.
The case was hopeful, though the gain could not be perceived in one, or two, hours; but at eight bells hardly a mile lay between the contending steamers. The first lieutenant wanted to open on the chase with the rifled gun on the top-gallant forecastle; but Somers refused permission, for while he was gaining on the Ben Ledi only in inches, he could not afford to lose feet by the recoil of the gun, until there was a better chance of hitting the mark. At two bells in the first dog watch, just as the sun was setting, the Ben Ledi doubled Frying Pan Shoals, passing close to the breakers. Then, as her people discovered a couple of vessels belonging to the blockading squadron, she sheered off, and went to the westward.
These changes, with the doubt and uncertainty which prevailed on board of the Ben Ledi, had been very favorable to the Firefly, now within half a mile of her. Two vessels from the blockading fleet had started to engage in the exciting work, but they were too late to help or hinder the pursuit. Somers gave the order to fire upon the Ben Ledi, which was now endeavoring to work round to the Beach Channel.
Though the darkness had settled down upon the chase, the Firefly continued the pursuit with unabated vigor. Her pilot was familiar with the channels, bars, and shoals. Shot after shot was fired at the Ben Ledi, and it was soon evident that one of them had in some way damaged her wheels, for she was rapidly losing ground. But now a battery on Oak Island suddenly opened on the Firefly.