Karl Baedeker 'father of modern tourism'. In 1846, Baedeker introduced his famous 'star' ratings (for sights, attractions and lodgings) in the third edition of his "Handbuch für Reisende durch Deutschland und den Oesterreichischen Kaiserstaat" - an idea based on the Murray guides star system. This edition was also his first 'experimental' red guide. He also decided to call his travel guides 'handbooks', following the example of John Murray III. Baedeker's early guides had tan covers, but from 1856 onwards, Murray's red bindings and gilt lettering became the familiar hallmark of all Baedeker guides as well, and the content became famous for its
Karl Baedeker (scientist) This was the first example of doping a semiconductor to change its properties and also the discovery of transparent conductive materials. He also observed a Hall effect in transparent copper iodide thin films that had the reverse sign to that in copper, an observation of what was later to be known as conduction by electron holes in semiconductors. This observation was critical in developing the theory of electron conduction in solids. Along with his graduate student Karl Steinberg, Baedeker studied the effect of varying concentration of iodine on the electrical properties of copper iodide. He also is credited with making