Telephone
While Alexander Graham Bell was experimenting with telegraph instruments in the early 1870s, he realized it might be possible to transmit the human voice over a wire by using electricity. By March 1876 he made a transmission, but the sound was very faint.
He improved his results over the next few months, including a critical test with this instrument on November 26, when he transmitted sound clearly between Cambridge and Salem, Massachusetts. It functioned as both a transmitter and a receiver. |
Artificial Heart
Dr. Jack G. Copeland implanted this Jarvik-7 heart in Michael Drummond on August 29, 1985. Drummond lived with the Jarvik-7 for a week before an organ transplant. It was the first authorized use of an artificial heart as a bridge to organ transplantation.
Dr. Robert K. Jarvik had developed the heart during the late 1970s, working with many other researchers. It consists of two ventricles (the heart's lower chambers) with air chambers and six titanium valves. It attaches to the patient's natural auricles (the heart's upper chambers).
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Light Bulb
Thomas Edison developed a practical light bulb toward the end of 1879. In 1880 he designed this version, the first to have all the essential features of a modern light bulb--an incandescent filament in an evacuated glass bulb with a screw base. Creating a successful filament was the most critical factor. For it to be practical, it had to glow when an electric current passed through it, possess high electrical resistance, and last a long time. |
Telegraph Key
The telegraph key Samuel Morse used on his first line in 1844 was very simple--a strip of spring steel that could be pressed against a metal contact. Alfred Vail, Morse's partner, designed this key, in which the gap was more easily adjustable because of changes in its spring tension. It was used on the expanding telegraph system, perhaps as early as the fall of 1844 and certainly by 1845. |
Telegraph
Samuel F. B. Morse conceived of an electromagnetic telegraph in 1832 and constructed an experimental version in 1835. He did not construct a truly practical system until 1844, when he built a line from Baltimore to Washington, D.C. This model incorporates basic features of the 1844 receiver. It accompanied an application for a patent, granted in 1849, in which he described a method for marking dots and dashes on paper. Within ten years after the first telegraph line opened, 23,000 miles of wire crisscrossed the country. The invention profoundly affected the development of the West, made railroad travel safer, and allowed businessmen to conduct their operations more profitably.
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Sugar Evaporation System
Norbert Rillieux, an African American inventor, patented his vacuum evaporation system in 1843. He designed it to evaporate the liquid part of sugar cane juice more efficiently, more safely, and less expensively than the open-kettle system then in use. Rillieux was unable to persuade sugar cane plantation owners to buy his machinery for several years. But its superiority became apparent almost immediately once it began to be used.
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Sewing Machine
Isaac Merritt Singer was the most flamboyant of 19th-century sewing machine inventors, having sharpened his skills as an actor before becoming an inventor. Around 1850, he began concentrating on improving an existing sewing machine. Success followed quickly. This 1853 model is a commercial sewing machine. The patent claims were for the methods of feeding the cloth, regulating the tension on the needle thread, and lubricating the needle thread so that leather could be sewn. The development of practical sewing machines contributed to the growth of the ready-made clothing industry in the late 19th and early 20th centuries.
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