CONTENTS

CHAPTERPAGE
I. The Aeroplane
How a Scientist Who Liked Boys and a Boy WhoLiked Science Followed the Fascinating Story ofthe Invention of the Aeroplane.
[3]
II. Aeroplane Development
How the Inventors Carried On the Art of AviationUntil It Became the Greatest of All Sportsand Then a Great Industry.
[49]
III. Aeroplanes To-day
Our Boy Friend and the Scientist Look OverModern Aeroplanes and Find Great ImprovementsOver Those of a Few Years Ago. AModel Aeroplane.
[91]
IV. Artificial Lightning Made and Harnessed
To Man's Use
Our Friends Investigate Nikola Tesla's Inventionfor the Wireless Transmission of Power, byWhich He Hopes to Encircle the Earth WithLimitless Electrical Power, Make Ocean and AirTravel Absolutely Safe, and Revolutionize LandTraffic.

[129]
V. The Motion Picture Machine
Machines That Make Sixteen Tiny Pictures PerSecond and Show Them at the Same Rate MagnifiedSeveral Thousand Times. Motion Picturesin School. Our Boy Friend Sees theWhole Process of Making a Motion Picture Play.
[164]
VI. Adventures With Motion Pictures
Perilous and Exciting Times in Obtaining MotionPictures. How the Machine Came to Be Inventedand the Newest Developments in Cinematography.
[195]
VII. Steel Boiled Like Water and Cut LikePaper
Our Boy Friend Sees How Science Has Turnedthe Greatest Known Heats to the Everyday Useof Mankind.
[224]
VIII. The Tesla Turbine
Dr. Nikola Tesla Tells of His New Steam TurbineEngine, a Model of Which, the Size of aDerby Hat, Develops More Than 110 HorsePower.
[263]
IX. The Romance of Concrete
The One Piece House of Thomas A. Edison andOther Uses of the Newest and Yet the OldestBuilding Material of Civilized Peoples, Seen Bythe Boy and His Scientific Friend.
[288]
X. The Latest Automobile Engine
Our Boy Friend and the Scientist Look Over theField of Gasoline Engines and See Some BigImprovements Over Those of a Few Years Ago.
[320]
XI. The Wireless Telegraph Up To The Minute
The Scientist Talks of Amateur Wireless Operators.The Great Development of Wireless ThatHas Enabled It to Save Three Thousand Lives.Long Distance Work of the Modern Instruments.
[332]
XII. More Marvels of Science
Color Photography, the Tungsten Electric Lamp,the Pulmotor, and Other New Inventions Investigatedby Our Boy Friend.
[352]