Tom laughed, and turned to inspect the motor. As he was looking it over, to locate the trouble, the door of the house opened and a pleasant-faced woman stepped out.
"Oh, Tom," she called. "I looked for you a moment ago, and you weren't here!"
"No, Mrs. Baggert," Tom replied, waving his hand in greeting to the housekeeper, "Rad and I just came back—quite suddenly—sooner than we expected to. Why? Did you want me?"
"Here's a letter that came for you," she went on.
Tom tore open the envelope, and rapidly scanned the contents of the missive.
"Hello!" he ejaculated half aloud. "It's from Abe Abercrombie, that miner I met when we were after the diamond-makers! He says he is on his way east to get ready to start on the quest for the Alaskan valley of gold, in the caves of ice. I had almost forgotten that I promised to make the attempt in the big airship. How did this letter come, Mrs. Baggert?" he asked.
"By special delivery. The messenger brought it a few minutes ago."
"Then we may see Abe any day now. Guess I'd better be looking over the RED CLOUD to see if it's in shape for a trip to the Arctic regions."
Tom's attention for the moment was taken off his little monoplane, and his memory went back to the strange scenes in which he and his friends had recently played a part, in searching for the cave of the diamond-makers on Phantom Mountain. He recalled the promise he had made to the old miner.
"I wonder if he expects us to start for Alaska with winter coming on?" thought Tom.