Nikola Tesla film in his laboratory in previous experiments (later identified as ""Roentgen rays"" or "X-Rays"). His early experiments were with Crookes tubes, a cold cathode electrical discharge tube. Tesla may have inadvertently captured an X-ray image—predating, by a few weeks, Wilhelm Röntgen's December 1895 announcement of the discovery of X-rays when he tried to photograph Mark Twain illuminated by a Geissler tube, an earlier type of gas discharge tube. The only thing captured in the image was the metal locking screw on the camera lens. In March 1896, after hearing of Wilhelm Röntgen's discovery of X-ray and X-ray imaging (radiography), Tesla
Invention (musical composition) Bach adapted and modified the form to what is considered to be a formal invention. Bach wrote 15 inventions (BWV 772–786) as exercises for his son, Wilhelm Friedemann Bach. Bach later wrote a set of 15 three-part inventions, called sinfonias (BWV 787–801). Invention (musical composition) In music, an invention is a short composition (usually for a keyboard instrument) with two-part counterpoint. (Compositions in the same style as an invention but using three-part counterpoint are known as "sinfonias." Some modern publishers call them "three-part inventions" to avoid confusion with symphonies.) Well-known are the fifteen inventions that make up the first half