Mr. Swift did not accompany his son in the airship, and when asked why he did not care to make the trip, said he was working on a new type of submarine boat, which he hoped to enter in the government trials, to win a prize. In the fourth volume of the series, called "Tom Swift and his Submarine," you may read how successful Mr. Swift was.
When the submarine, called the Advance, was finished, the party made a trip to recover three hundred thousand dollars in gold from a sunken treasure ship, off the coast of Uruguay, South America. They sailed beneath the seas for many miles, and were in great peril at times. One reason for this was that a rival firm of submarine builders got wind of the treasure, and tried to get ahead of the Swifts in recovering it. How Tom and his friends succeeded in their quest, how they nearly perished at the bottom of the sea, how they were captured by a foreign war vessel, and sentenced to death, how they fought with a school of giant sharks and how they blew up the wreck to recover the money is all told of in the book.
On their return to civilization with the gold, Mr. Swift, Tom, and their friends deposited the money in the Shopton Bank, where Ned Newton worked. Ned was a bright lad, but had
