[1] Illustrations by courtesy of the Lake Torpedo Boat Co., unless otherwise indicated.[2] The following information and statistics by courtesy of The Panama Canal, Washington office.[3] Illustrations by courtesy of the Columbia Graphophone Co.[4] Illustrations by courtesy of the Hendee Manufacturing Co.[5] Courtesy of the Waltham Watch Company, and “The American Boy.”[6] Illustrations by courtesy of the Remington Arms-Union Metallic Cartridge Company, unless otherwise indicated.[7] Illustrations by courtesy of Plymouth Cordage Co.[8] Illustrations by courtesy of Colt’s Patent Fire Arms Manufacturing Co.[9] Illustrations by courtesy of Consolidated Fireworks Company of America.[10] Illustrations by courtesy of Eastman Kodak Company.[11] Illustrations by courtesy of R. Hoe & Co.[12] Illustrations by courtesy of the A.I. Root Co.[13] Illustrations by courtesy of the Hotpoint Electric Heating Co.[14] Illustrations by the courtesy of the American Telephone and Telegraph Co.[15] Illustrations by courtesy of the Otis Elevator Co.[16] Illustrations by courtesy of the International Silver Co.[17] Illustrations by courtesy of the McClure Co.[18] Illustrations by courtesy of New York Edison Co., unless otherwise indicated.[19] Illustrations by courtesy of The Curtis Publishing Co.[20] Courtesy of George A. Hormel & Co.[21] Courtesy of The Field, New York City.[22] Courtesy of The Field, New York City.[23] Courtesy of the California Redwood Association.[24] Illustrations by courtesy of The Brunswick-Balke-Collender Co.[25] Illustrations by courtesy of the American Pin Company.[26] Illustrations by courtesy of the Common Sense Gum Co. Story by courtesy of the American Chicle Co. and the Common Sense Gum Co.[27] Illustrations by courtesy of The Brunswick-Balke-Collender Co.[28] Illustrations by courtesy of the Addressograph Co.[29] Illustrations by courtesy of the Pyrene Manufacturing Co.[30] Illustrations by courtesy of Gatchel & Manning.[31] Courtesy of Mr. Charles L. Trout.[32] Illustrations by courtesy of the Bethlehem Steel Co.[33] Illustrations by courtesy of the Bethlehem Steel Co.[34] Illustrations by courtesy of the Bethlehem Steel Co.[35] Illustrations by courtesy of the Bethlehem Steel Co.[36] Illustrations by courtesy of the Bethlehem Steel Co.[37] Illustrations by courtesy of the Bethlehem Steel Co.[38] Illustrations by courtesy of the Bethlehem Steel Co.[39] Illustrations by courtesy of the Bethlehem Steel Co.[40] Illustrations by courtesy of the Bethlehem Steel Co.[41] Illustrations by courtesy of the Bethlehem Steel Co.[42] Illustrations by courtesy of the Bethlehem Steel Co.[43] Illustrations by courtesy of the Bethlehem Steel Co.[44] Illustrations by courtesy of the Bethlehem Steel Co.[45] Illustrations by courtesy of the Bethlehem Steel Co.[46] Illustrations by courtesy of United Shoe Machinery Co.[47] Courtesy of James Boyd & Bro., Inc.[48] Courtesy of American LaFrance Fire Engine Co.[49] Courtesy of American LaFrance Fire Engine Co.[50] Courtesy of American LaFrance Fire Engine Co.[51] Courtesy of American LaFrance Fire Engine Co.[52] Illustrations by courtesy of American Cyanamid Company.[53] Courtesy of The Strauss Bascule Bridge Co.[54] Courtesy of The American Magazine.[55] Illustrations by courtesy of the Railway Age Gazette and Standard Steel Car Co.[56] Illustrations by courtesy of Diamond Crystal Salt Co.[57] Illustrations by courtesy of the General Motors Truck Co.[58] Illustrations by courtesy of Jacobs & Davies, Engineers.[59] Illustrations by courtesy of Ford Motor Co.[60] Courtesy of the Pennsylvania Railroad Co.[61] Courtesy of the Pennsylvania Railroad Co.[62] Courtesy of the Pennsylvania Railroad Co.[63] Courtesy of the Pennsylvania Railroad Co.[64] Courtesy of the Pennsylvania Railroad Co.[65] Courtesy of the Pennsylvania Railroad Co.[66] Courtesy of the General Electric Co.[67] Courtesy of the Westinghouse Co.[68] Illustrations by courtesy of International Harvester Company of America, unless otherwise indicated.[69] Illustrations by courtesy of the Nicholas Power Co.[70] Illustrations by courtesy of Endicott, Johnson & Co.[71] Courtesy of Mr. Charles L. Trout.[72] Illustrations by courtesy of Cutler-Hammer Mfg. Co.