Scientific American, Volumes 148-149

24 West airplane airship ALBERT G altitude Amateur Telescope Amateur Telescope Makers amount atoms Century of Progress chemical Chicago CHICAGO GEAR City color Company cosmic rays cost dollars Editor Electric engine equipment experience eyepiece fact feet flying fuel gear Gegenschein give glass heat horsepower Hotel HYGEIA inches increase industry interesting invention Japan laboratory lamp light lines machine manufacture material ment metal method microscope miles milk mirror motor MUNN operation Optical ORSON passengers Patent percent photograph picture pilot plane plant possible postpaid pounds practical problem Professor radio rays recently SCIENTIFIC AMERICAN Send ship Slide Rule speed surface tanks telepathy temperature tion tube ture United Veeder-Root vitamin vitamin D welding West 40th Street writing York York City