"It seems according to Mr. Illingway's letter, that you have to go to the coast and strike into the interior until you are near the old city of Poltec. That used to be it's name, but Mr. Illingway says it may be abandoned now, or the name changed. But I guess we can find it.
"Then, according to what he could learn from the African natives, who talked with the white man, the best way is to hire ox carts and strike into the jungle. That's the only way to carry our baggage, and the dirigible balloon which I'm going to take along."
"Pretty uncertain way to look for a buried city of gold," commented Mr. Swift. "But I suppose even if you don't find it you'll have the fun of searching for it, Tom."
"But we are going to find it!" the lad declared. We'll get there, you'll see!"
"But how are you going to know it when you see it?" asked his father. "If it's underground even a balloon won't help you much."
"It's true it is underground," agreed Tom, "but there must be an entrance to it somewhere, and I'm going to hunt for that entrance. Mr. Illingway writes that the city is a very old one, and was built underground by the priests of some people allied to the Aztecs. They wanted a refuge in times of war and they also hid their valuables
