“Floating rib,” said Matthew Reed. “I knew a man once who had a floating rib.”
“Joke,” said Mac.
“Well, people do have such things as floating ribs,” protested Matthew; “ask Dr. Brent.”
“Very clever,” said Tom Langford. “Let’s all laugh.”
“Hope you choke,” grunted Matthew.
The next day the ribs were fastened in place, and these, of course, had a bracing effect on the frame. On the upper plane there were twenty-one ribs, placed at even spaces across the frame. On the lower, one rib was omitted in the center, where there would be no cloth covering on account of the open space required to hold the passenger. Thus the ribs were something over a foot apart. Since the frames were only three feet wide and the ribs four feet long, it followed that they had to project a foot over one edge, and this of course must be the back, or after, edge. The front or abruptly curved end of each rib was brought flush with the long beam and screwed down to it with a long, flatheaded screw. Then where it crossed the after beam it was also screwed down. They were careful to see that each one was correctly squared with the long bars, so that the ribs, when placed, were parallel with each other.
When their work was finished, the boys squatted about, surveying the result of their labor and commenting on the scientific and shipshape appearance it was beginning to assume. The curved ribs had transformed the fencelike frames into two graceful pieces of lattice, with a sort of aerial, buoyant aspect that immediately suggested the aeroplane. Up to this point the work might have been intended for any one of a dozen purposes. Not so now.
“She’s going to be all right,” said Mac. “Where’ll we try her out—down the hill?”
“We’d better try her on the level first,” said Harry.
“Certainly, we’ll do everything on the level,” ventured Matthew.