"Yes. Mr. Baxter and I are going to make up a lot of the chemical compound that—we discovered through using it on the blazing tree—will best do the trick. Then I'm going to try it on a pit fire, and after that on a big blaze with an airship."
"Let me know when you do," begged Ned. "I want to see you do it."
"I'll send you word," promised the young inventor.
Then he began several days and nights of hard work. And he was glad to have the chance to occupy himself, for, though Tom professed not to be much affected by the departure of Mary Nestor, he really was very lonesome.
"How is her uncle, Barton Keith, by the way?" asked Ned, when he called on his chum one day, to find him reading a letter which needed but half an eye to tell was from Mary.
"About as usual," was the answer. "He sends word by Mary that he'll be glad to see us any time we want to call. He has some nice offices in the Landmark Building."
"Those papers proving his right to the oil land, which you recovered from the sunken ship for him, must have made his fortune."
"Well, yes—that and other things," agreed Tom. "Say, we had some exciting times on that undersea search, didn't we?"
"Did you call on Mr. Keith when you went to Newmarket with Mary?" Ned wanted to know, for he and Tom had taken quite a liking to Miss Nestor's uncle.
"No, I didn't get a chance. Besides, I wanted to keep away from the Landmark Building."