The medium of the air having been conquered, Tom again turned his attention to the water, or rather, under the water, and he and his father made a submarine. Then he built an electric runabout, the speediest car on the road.
It was when Ton Swift had occasion to send his wireless message from a lonely island where he had been shipwrecked that he was able to do Mr. and Mrs. Nestor a valuable service, and this increased the regard which Miss Mary Nestor felt for the young inventor, a regard that bid fair, some day, to ripen into something stronger.
Tom Swift might have made a fortune when he set out to discover the secret of the diamond makers. But Fate intervened, and soon after that quest he went to the caves of ice, where he and his friends met with disaster. In his sky racer Tom broke all records for speed, and when he went to Africa to rescue a missionary, had it not been for his electric rifle the tide of battle would have gone against him and his party.
Marvelous, indeed, were the adventures underground, which came to Tom when he went to look for the city of gold, but the treasure there was not more valuable than the platinum which Tom sought in dreary Siberia by means of his air glider.
Tom thought his end had come when he fell into captivity among the giants; but even that turned out well, and he brought two of the giants away with him. Koku, one of the two giants, became devotedly attached to the lad, much to the disgust of Eradicate Sampson, the old negro who had worked for the Swifts for a generation, and who, with his mule Boomerang, "eradicated" from the place as much dirt as possible.
With his wizard camera Tom did much to advance the cause of science. His great searchlight was of great help to the United States government in putting a stop to the Canadian smugglers, while his giant cannon was a distinct advance in ordnance, not excepting the great German guns used in the European war.
When Tom perfected his photo telephone the last objection to rendering telephonic conversation admissible evidence in a law court was done away with, for by this invention a person was able to see, as well as to hear, over the telephone wire. One practically stood face to face with the person, miles away, to whom one was talking.
The volume immediately preceding this present one is called: "Tom Swift and His Aerial Warship." The young inventor perfected a marvelous aircraft that was the naval terror of the seas, and many governments, recognizing what an important part aircraft were going to play in all future conflicts, were anxious to secure Tom's machine. But he was true to his own country, though his rivals were nearly successful in their plots against him.
The Mars, which was the name of Tom's latest craft, proved to be a great success, and the United States government purchased it. It was not long after the completion of this transaction that the events narrated in the first chapter of this book took place.
Mr. Damon and Tom had been firm friends ever since the episode of the motor cycle, and the eccentric gentleman (who blessed so many things) often went with Tom on his trips. Besides Mary Nestor, Tom had other friends. The one, after Miss Nestor, for whom he cared most (if we except Mr. Damon) was Ned Newton, who was employed in a Shopton bank. Ned also had often gone with Tom, though lately, having a better position, he had less time to spare.