When Ned had gone Tom got out pencil and paper, and was busily engaged in making some intricate calculations. He drew odd little sketches on the margin of the sheet, and then wrote out a list of the things he would need to construct the new aeroplane.
This finished, he went to Mr. Jackson, the engineer, and asked him to get the various things together, and to have them put in the special shop where Tom did most of his work.
"I want to get the machine together as soon as I can," he remarked to the engineer, "for it will need to be given a good tryout before I enter in the race, and I may find that I'll have to make several changes in it."
Mr. Jackson promised to attend to the matter right away, and then Tom went in to talk to his father about the motor that was to whirl the propeller of the new air craft.
Mr. Swift had improved very much in the past few days, and though Dr. Gladby said he was far from being well, the physician declared there was no reason why he should not do some inventive work.
He and Tom were deep in an argument of gasoline motors, discussing the best manner of attaching the fins to the cylinders to make them air-
