Page 137 - Expanded Media & the MediaPlex

Expanded Media - and the MediaPlex 137/206
William Crookes: Crookes’ Tube 1875.
A hugely important step in the acquisition of the basic science underpinning aspects of new media developments, Crookes’ Tube was a high-vacuum glass vessel into which an electrical cathode could be inserted, with an anode at the other end of the tube. The high-vacuum meant that there were very few molecules of air to intercept the ‘cathode rays’ emitted from the cathode (when an electrical charge was applied), and these rays could ‘travel’ (at high speed - about 20% light-speed) in a straight line through the tube, leaving a shadow when interrupted by a mask - the cross-shaped object (see above). At this time, atoms were thought to be the smallest particle in existence, but later J.J. Thompson realised that ‘cathode rays’ were actually streams of positively charged electrons (so Crooke’s Tube led to the discovery of the electron). Later in the century Heinrich Hertz discovered that electro-magnets placed around the tube could deflect the cathode rays - this was the basis of the invention of electronic television in the 1930s. And in 1895 Wilhelm Röntgen discovered X-Rays using a modified Crookes’ tube.
Considering the impact of the cathode-ray-tube (offspring of Crooke's Tube) - through Television and the Computer Screen in the 20th century, Crooke's invention may be the most important of the media innovations created in the 19th century. The Cathode Ray Tube (CRT) was the dominant technology in the development of the graphical user interface from Douglas Engelbart’s Augmentation research in the late 1960s, really to the 21st century, when LCD (Liquid-Crystal Diodes) became dominant, offering flatter, lighter, brighter, higher-resolution monitor screens in both desktop and laptop computers.