CHAPTER XV
THE SECRET BOOK
On the island of mysteries Jack watched with increasing astonishment as the jet plane soared away. It climbed up until it looked to be the size of a star, let out a scream, then faded with the speed of sound into the blue sky.
“Some plane!” he exclaimed, straining his eyes for one last glimpse of it. A plane like that could change the whole science of aviation. Yes, it’s a military secret, but whose secret? That’s the question. He was about to begin his homeward journey when a book, lying on the rocks, caught his attention.
Murder at Midnight, he read on the cover. “So that’s what they read!”
Picking up the book, he flipped it open, then a whistle escaped his lips. Two thirds of the pages of the original book had been replaced by pages on which clippings had been pasted. “A scrapbook! How strange!” He stood staring at it.
A moment later he nearly dropped it in his excitement. “It’s all about that mysterious plane! What a find!” he whispered.
Sitting down upon a flat rock, he began to read. There were articles in English, French, German, and Italian. Many he could not read at all, but the articles in English were more than enough to satisfy his curiosity. Much that he read about equalizers, reflecting blades, direpeller blades, slip streams, and burbles he understood only in part. At last he came to an article which gave him the desired information. This article read in part:
“Rocket propulsion, of course, is not a new thing; the basic idea is centuries old. As applied to aerial warfare it was employed on a crude basis even in World War I. The Italians made public an experimental flight of a propellerless jet-type plane several years ago. Long before that, automobiles were driven by rocket engines, and special rockets for making meteorological soundings in the substratosphere were in use....
“Nevertheless, the Anglo-American jet-propelled airplane represents the broadest application of the principle yet achieved.
“The jet plane carries no oxygen for its engine: its jet propulsion engine uses oxygen from the air. This engine has fewer parts and is of simpler construction than the traditional engine. It operates a mechanism which compresses the air. This air is mixed with atomized fuels such as gasoline, kerosene, alcohol, or some other fuels of the hydrocarbon family, rich in hydrogen. From that point forward the operation is the same as in the rocket engine; that is to say, the gas is released and ignited, the resulting expansion and emission through the jet providing the power....