In The Boy Aviators on Secret Service, the second volume of the Boy Aviators’ series, we find them in the mysterious region of the Everglades. Once again they demonstrated—this time for Uncle Sam—the almost limitless possibilities of the two greatest inventions of modern times—the aëroplane and wireless telegraphy. In this book we related how the secret explosive factory was located and put out of commission, and what dangers and difficulties surrounded the boys during the process.

Not long after this a strange combination of circumstances resulted in the boys taking a voyage to Africa. In The Boy Aviators In Africa you may read how they discovered the ivory hoard in the Moon Mountains, and how the Arab slave trader, who had cause to fear them, made all sorts of trouble for them. The first aëroplane to soar above the trackless forests of the Dark Continent conveyed them safely out of their dilemmas, and indirectly was the cause of their being able to voyage back to America on a fine yacht.

The boys had figured on resting up after this, but the love of adventure that stirred in their blood, as well as their warm friendship for Billy Barnes, prompted them to take part in a cross-continent flight against great odds. The story of the contest, The Boy Aviators in Record Flight, related stirring incidents from coast to coast. Readers of that volume will readily summon to mind the ruse by which the lads escaped the cowboys and baffled some renegade Indians and, finally, their fearful battle in midair with the sand storm.

The story of an old Spanish galleon enthralled in the deadly grip of the Sargasso Sea furnished the inspiration for the tale of the Boy Aviators’ Treasure Quest. But they were not alone on their hunt for the long-lost treasure trove. Luther Barr, a bad old man who had caused them much trouble before, fitted out a rival expedition. High above the vast ocean of Sargasso weed the boys had to fight for their lives with a crew of desperate men in a powerful dirigible craft. How they won out, and through what other adventures they passed—including the surprising one of the “rat ship,”—you must read the volume to discover, as we have not space to detail all that befell them on that voyage.

Then came what was, in many respects, their queerest voyage of all—the flight above the Antarctic fields of eternal ice, in search of the goal of discoverers of half a dozen nationalities, the South Pole. The Boy Aviators’ Polar Dash was a volume full of swift action and enterprise. Many hardships were endured and dangers faced, but the boys did not flinch when duty required their best of them. They emerged from the frozen regions having achieved a signal triumph, but one which would not have been possible of accomplishment without their aëroplane.

Having thus briefly sketched the previous careers of the Boy Aviators, we shall give a short account of how they came to be on Brig Island, and then press on with our story. About a month before the present story opens then, a scientific friend of Mr. Chester’s, Dr. Maxim Perkins, had called on the Boy Aviators’ father and requested the aid of the young aërial inventors in some problems that were bothering him. Dr. Perkins was already an aviator of some note, but his achievements had not found their way into the newspapers as, like most scientific men, he did not care for publicity in connection with his experiments.

In common with the rest of the civilized world Dr. Perkins—horrified at a mid-ocean tragedy in which hundreds of lives were sacrificed—had set his wits to work to devise some means of life saving—in addition to the regular boat equipment—which might be easily carried by ocean liners. He was convinced that it would be feasible for vessels of that description to carry an auxiliary fleet of what he termed “dirigible-hydro-aëroplanes.” By this rather clumsy name he meant a combination of the hydroplane, dirigible and aëroplane. But although his ideas on the subject were clear enough in theory, he was rather hazy about the practical side of the matter, and this was the object of his call on Mr. Chester—to ask the aid of the Boy Aviators in carrying out his experiments.

To make a long story short, arrangements were finally completed by which the doctor had leased Brig Island, and had set up on it such sheds and appliances as would be needed by the boys in their work. These included a wireless, by means of which communication with the mainland might be kept up—via Portland—and also a unique piece of apparatus (if such it could be called) of which we shall learn in the next chapter.

The boys had now spent two busy weeks on the island, and the work that they had mapped out for themselves was so nearly completed that they had felt justified that morning in wirelessing Dr. Perkins to come and see how things were going on. As we have seen, their stay on the island had not been altogether tranquil. The spot had been used for years by the fishermen as a sort of stowage place for their apparatus, and also, sometimes, as a summer residence. With the coming of the boys and their necessarily private work, all this had been changed, and the resentment of the fishermen had been bitter. Of all the complainers, Zenas and his son were the most aggressive, however, and had openly threatened to drive the boys off the island.

To avoid being taken by surprise the lads had rigged up the electric fence, which device, as readers of The Boy Aviators on Secret Service will recall, had been used by them before with success to repel unwelcome visitors.