Alexander Graham Bell - scientist, inventor and founder of the Bell Telephone Company. In addition to his work in the field of communications, he is responsible for important inventions in aviation. He researched the mechanics of speech, so in 1872 he founded a school for teachers for the deaf-mute in Boston. While teaching at this school, he constructed an artificial ear that registers tones on a shaded glass plate. He invented the electric telephone in 1876. This invention has been improved several times, and has been in use since 1877. He also constructed a photophone, which works on the principle of converting changes in light intensity into sound. He proposed the use of wax for phonograph records and found an electrical method for detecting metallic objects in the human body. Preoccupation with his mother's deafness led him to study acoustics and to develop the technique of speaking in clear, modulated tones directly into his mother's forehead. Bell's father taught him and his brothers not only to write visible speech, but also to recognize any symbol and accompanying sound.
Thomas Alva Edison - physicist and prolific inventor who received almost no formal education, having been kicked out of school as a retard and tutored by his mother. At the age of 14, he was already an entrepreneur. He set up a laboratory in an abandoned wagon, as well as a printing press for his newspaper, which he mostly wrote himself. At the age of sixteen, he became a telegraph operator and began a career as an inventor and invented and patented an electrical apparatus for recording votes in elections. Later, he invented the paper tape "ticker", used to send stock market prices across the country. His more notable inventions include the carbon granule microphone, an improvement on Bell's telephone, the phonograph, and the electric light bulb. While working on the light bulb, he also discovered the "Edison effect", the fact that electric current flows from the heated fiber to the nearby electrode, but not in the opposite direction. Edison's influence on life in the 20th century was enormous. He was one of the first inventors to apply the principles of mass production, and he is considered to have created the first industrial research laboratory.
Author: Nebojsa Djumic
Publisher: Poste Srpske a.d. Banjaluka
