“The only trouble is he’s been there long enough to have heard most of it.” suggested Ned.  They could talk freely now, for in going into the parlor Mr. Swift had tightly closed the door after him.  They could just hear the murmur of his voice speaking to Andy.

“Well, even if he does guess about the city of gold, and its location, I don’t believe he’ll try to go there,” remarked Tom, after a pause.

A moment later they heard Mr. Swift letting Andy out of the front door, and then the inventor rejoined his son and the others.  He held an open letter in his hand.

“This is strange—­very strange,” he murmured.

“What is it?” asked Tom quickly.

“Why.  Mr. Foger has written to me asking to be allowed to sell some of our patents and machines on commission.”

“Sell them on commission!” exclaimed his son.  “Why does a millionaire like Mr. Foger want to be selling goods on commission?  It’s only a trick!”

“No, it’s not a trick,” said Mr. Swift slowly.  “He is in earnest.  Tom, Mr. Foger has lost his millions.  His fortune has been swept away by unfortunate investments, he tells me, and he would be glad of any work I could give him.  That’s why Andy brought the letter to-night.  I just sent him back with an answer.”

“What did you say, dad?”

“I said I’d think it over.”

“Mr. Foger’s millions gone,” mused Tom.

“And Andy in there listening to what we said about the city of gold,” added Ned.  “No wonder he was glad the door was open.  He’d be there in a minute, Tom, if he could, and so would Mr. Foger, if he thought he could get rich.  He wouldn’t have to sell goods on commission if he could pick up a few of the golden images.”

“That’s right,” agreed Tom, with an uneasy air.  “I wish I knew just how much Andy had heard.  But perhaps it wasn’t much.”

The time was to come, however, when Tom was to learn to his sorrow that Andy Foger had overheard a great deal.

“Bless my bankbook!” exclaimed Mr. Damon.  “I never dreamed of such a thing!  Andy had every reason in the world for not wanting us to know he was in there!  No wonder he kept quiet.  I’ll wager all the while he was as close to the open door as he could get, hoping to overhear about the location of the place, so he could help his father get back his lost fortune.  Bless my hatband!  It’s a good thing Mrs. Baggert told us he was there.”

They all agreed with this, and then, as there was no further danger of being overheard, they resumed their talk about the city of gold.  It was decided that they would have to wait the arrival of another letter from Mr. Illingway before starting for Mexico.

“Well, as long as that much is settled, I think I’d better be going home,” suggested Mr. Damon.  “I know my wife will be anxious about me.”

“I’ll get out the sky racer and you’ll be in Waterford in a jiffy,” said Tom, and he kept his word, for the speedy aeroplane carried him and his guest rapidly through the night, bringing Tom safely back home.