of California, Berkeley, in 1900 Practical air conditioner designed by Willis Carrier in 1902 Geiger counter (measures radioactivity) invented by Hans Geiger in 1908 Pierre and Marie Curie discover radium and polonium, they coin the term 'radioactivity'. Third law of thermodynamics by Walther Nernst Quantum Hypothesis by Max Planck in 1900 The Bacillus Calmette-Guérin (BCG) immunization for tuberculosis is first developed. Technology Widespread application of the internal combustion engine including mass production of the automobile. Rudolf Diesel demonstrated the diesel engine in the 1900 Exposition Universelle (World's Fair) in Paris using peanut oil fuel (see biodiesel). The Diesel engine takes the Grand Prix. The exposition was attended by 50 million people. The same year Wilhelm Maybach designed an engine built at Daimler Motoren Gesellschaft—following the specifications of Emil Jellinek—who required the engine to be named Daimler-Mercedes after his daughter, Mercédès Jellinek. In 1902, the Mercedes 35 hp automobiles with that engine were put into production by DMG. Wide popularity of home phonograph. "The market for home machines was created through technological innovation and pricing: Phonographs, gramophones, and graphophones were cleverly adapted to run by spring-motors (you wound them up), rather than by messy batteries or treadle mechanisms, while the musical records were adapted to reproduce loudly through a horn attachment. The cheap home machines sold as the $10 Eagle graphophone and the $40 (later $30) Home phonograph in 1896, the $20 Zon-o-phone in 1898, the $3 Victor Toy in 1900, and so on. Records sold because their fidelity improved, mass production processes were soon developed, advertising worked, and prices dropped from one and two dollars to around 35 cents.". In 1907, a Victor Records recording of Enrico Caruso singing Ruggero Leoncavallo's "Vesti la giubba" becomes the first to sell a million copies. 1899–1900 – Thomas Alva Edison of Milan, Ohio, invents the nickel-alkaline storage battery. On May 27, 1901, Edison establishes the Edison Storage Battery Company to develop and manufacture them. "It proved to be Edison's most difficult project, taking ten years to develop a practical alkaline battery. By the time Edison introduced his new alkaline battery, the gasoline powered car had so improved that electric vehicles were becoming increasingly less common, being used mainly as delivery vehicles in cities. However, the Edison alkaline battery proved useful for lighting railway cars and signals, maritime buoys, and miners lamps. Unlike iron ore mining with the Edison Ore-Milling Company, the heavy investment