[37] The caliber of a gun is the gage, or diameter of the bore of its barrel. Thus a gun of 3-inch caliber means that the bore is 3 inches in diameter; a gun that has a caliber of 45 centimeters means that its bore is 45 centimeters across. A centimeter is 1/100 of a meter and a meter is 39.37 inches.
[38] For a full description of the trajectory of bullets, see Shooting for Boys, by the present authors, and published by Moffat, Yard & Co., New York
[39] A full description of the Lewis machine gun for airplane work will be found in How to Fly by the present author and published by D. Appleton and Co., of New York.
[40] This means she sinks into the water 17 feet.
[41] These are real rubies, sapphires, and other gems made of chemicals in an oxyhydrogen furnace.
Transcriber’s Notes:
Obvious punctuation errors repaired.
Page 29, “to-together” changed to “together” (bring the ends together)
Page 94, “PPROPELLER” changed to “PROPELLER” (COVER AND PROPELLER)