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... W A T T ? James Watt ( ) Scottish inventor and mechanical engineer, renowned for his improvements of the steam engine. Watt was born on January 19, 1736, in Greenock, Scotland. He worked as a mathematical-instrument maker from the age of 19 and soon became interested in improving the steam engines, invented by the English engineers Thomas Savery and Thomas Newcomen, which were used at the time to pump water from mines. Watt determined the properties of steam, especially the relation of its density to its temperature and pressure, and designed a separate condensing chamber for the steam engine that prevented enormous losses of steam in the cylinder and enhanced the vacuum conditions. Watt's first patent, in

1769, covered this device and other improvements on Newcomen's engine, such as steam-jacketing, oil lubrication, and insulation of the cylinder in order to maintain the high temperatures necessary for maximum efficiency. At this time, Watt was the partner of the British inventor John Roebuck, who had financed his researches. In 1775, however, Roebuck's interest was taken over by British manufacturer Matthew Boulton, owner of the Soho Engineering Works at Birmingham, and he and Watt began the manufacture of steam engines. Watt continued his research and patented several other important inventions, including the rotary engine for driving various types of machinery; the double- action engine, in which steam is admitted alternately into both ends of the cylinder; and the steam indicator, which records the steam pressure in the engine. He retired from the firm in 1800 and thereafter devoted himself entirely to research work.

The misconception that Watt was the actual inventor of the steam engine arose from the fundamental nature of his contributions to its development. The centrifugal or flyball governor, which he invented in 1788, and which automatically regulated the speed of an engine, is of particular interest today. It embodies the feedback principle of a servomechanism, linking output to input, which is the basic concept of automation. The electrical unit, the watt, was named in his honor. Watt was also a renowned civil engineer, making several surveys of canal routes. He invented, in 1767, an attachment that adapted telescopes for use in measurement of distances. Watt died in Heathfield, England, on August 19, 1819.

... W E S T I N G H O U S E ? George Westinghouse ( ), American inventor, engineer, and industrialist. Westinghouse was born in Central Bridge, New York, and educated at what is now Union College and the University at Schenectady, New York. His first important invention, developed while he was employed in his father's factory in Schenectady, was a so-called railway frog, a device permitting trains to cross from one track to another. He devised his most famous invention, the air brake, about Although successfully demonstrated in 1868, the air brake did not become standard equipment until after the passage of the Railroad Safety Appliance Act in Westinghouse invented many other safety devices, especially for automatic railway signaling; developed a system for transporting natural gas; and acquired more than 400 patents, including many for alternating-current machinery. With Charles Steinmetz, he pioneered in the use of alternating-current power in the U.S.

... Z E E M A N ? Pieter Zeeman ( ), Dutch physicist and Nobel laureate. He is best known for his discovery of the Zeeman effect. Zeeman was born in Zonnemaire and educated at the Leiden University, where he taught until he became professor of physics at the University of Amsterdam in In 1896 Zeeman discovered that the spectral lines of a light source subjected to a strong magnetic field were split into several components, each of which was polarized. This phenomenon, known as the Zeeman effect, confirmed the electromagnetic theory of light. Zeeman shared the 1902 Nobel Prize in physics with the Dutch physicist Hendrik Antoon Lorentz for their joint research into the influence of magnetism upon radiation.

... Z W O R Y K I N ? Vladimir Kosma Zworykin ( ), American physicist and electronic engineer, known for his developmental work in television. Zworykin was born in Murom, Russia, and educated at the Institute of Technology in Saint Petersburg, the Collège de France, and, after his immigration to the United States in 1919, at the University of Pittsburgh, Pennsylvania. He became an American citizen in In 1929 he became director of the Electronic Research Laboratory of the Radio Corporation of America (RCA) at Princeton, New Jersey. Important contributions were made by Zworykin to both the transmission and the reception of television. He was largely responsible for the development, during the 1920s and '30s, of the television camera and picture tube. He also directed the group that in 1939 successfully produced a powerful electron microscope