Alexander Graham Bell

The photo phone

Another of Bell's inventions was the photo phone, a device enabling the transmission of sound over a beam of light, which he developed together with Charles Sumner Tainter. The device employed light-sensitive cells of crystalline selenium, which has the property that its electrical resistance varies inversely with the illumination (i.e., the resistance is higher when the material is in the dark, and lower when it is lighted). The basic principle was to modulate a beam of light directed at a receiver made of crystalline selenium, to which a telephone was attached. The modulation was done either by means of a vibrating mirror, or a rotating disk periodically obscuring the light beam.

This idea was by no means new. Selenium had been discovered by Jöns Jakob Berzelius in 1817, and the peculiar properties of crystalline or granulate selenium were discovered by Willoughby Smith in 1873. In 1878, one writer with the initials J.F.W. from Kew described such an arrangement in Nature in a column appearing on June 13, asking the readers whether any experiments in that direction had already been done. In his paper on the photo phone, Bell credited one A. C. Browne of London with the independent discovery in 1878—the same year Bell became aware of the idea. Bell and Tainter, however, were apparently the first to perform a successful experiment, by no means any easy task, as they even had to produce the selenium cells with the desired resistance characteristics themselves.

In one experiment in Washington, D.C. the sender and the receiver were placed on different buildings some 700 feet (213 metres) apart. The sender consisted of a mirror directing sunlight onto the mouthpiece, where the light beam was modulated by a vibrating mirror, focused by a lens and directed at the receiver, which was simply a parabolic reflector with the selenium cells in the focus and the telephone attached. With this setup, Bell and Tainter succeeded to communicate clearly.

The photophone was patented on December 18, 1880, but the quality of communication remained poor and the research was not pursued by Bell. Later on this helped in the discovery of fiber optics and laser communication systems.


Metal detector
Bell is also credited with the invention of the metal detector in 1881. The device was hurriedly put together in an attempt to find the bullet in the body of U.S. President James Garfield. The metal detector worked, but didn't find the bullet because the metal bedframe the President was lying on confused the instrument. Bell gave a full account of his experiments in a paper read before the American Association for the Advancement of Science in August 1882. Though unsuccessful in its first incarnation, this achievement would eventually change the nature of physical security.


The hydrofoil
The March 1906 Scientific American article by American hydrofoil pioneer William E. Meacham explained the basic principle of hydrofoils. Bell considered the invention of the hydroplane as a very significant achievement. Based on information gained from that article he began to sketch concepts of what is now called a hydrofoil boat.

Bell and Casey Baldwin began hydrofoil experimentation in the summer of 1908 as a possible aid to airplane takeoff from water. Baldwin studied the work of the Italian inventor Enrico Forlanini and began testing models. This led him and Bell to the development of practical hydrofoil watercraft.

During his world tour of 1910–1911 Bell and Baldwin met with Forlanini in France. They had rides in the Forlanini hydrofoil boat over Lake Maggiore. Baldwin described it as being as smooth as flying. On returning to Baddeck a number of designs were tried culminating in the HD-4, using Renault engines. A top speed of 54 miles per hour was achieved, with rapid acceleration, good stability and steering, and the ability to take waves without difficulty.In 1913, Dr. Bell hired Walter Pinaud, a Sydney yacht designer and builder as well as the proprietor of Pinaud's Yacht Yard in Westmount, Nova Scotia to work on the pontoons of the HD-4. Pinaud soon took over the boatyard at Bell Laboratories on Beinn Bhreagh, Bell's estate near Baddeck, Nova Scotia. Pinaud's experience in boatbuilding enabled him to make useful design changes to the HD-4 however soon WWI intervened. After WWI work began again on the HD-4. Bell's report to the navy permitted him to obtain two 350 horsepower (260 kW) engines in July 1919. On September 9, 1919 the HD-4 set a world's marine speed record of 70.86 miles per hour. This record stood for ten years.


Aeronautics
Bell was a supporter of aerospace engineering research through the Aerial Experiment Association, officially formed at Baddeck, Nova Scotia in October 1907 at the suggestion of Mrs. Mabel Bell and with her financial support. It was headed by the inventor himself. The founding members were four young men, American Glenn H. Curtiss, a motorcycle manufacturer who would later be awarded the Scientific American Trophy for the first official one-kilometre flight in the Western hemisphere and later be world-renowned as an airplane manufacturer; Frederick W. "Casey" Baldwin, the first Canadian and first British subject to pilot a public flight in Hammondsport, New York; J.A.D. McCurdy; and Lieutenant Thomas Selfridge, an official observer from the U.S. government. One of the project's inventions, the aileron, is a standard component of aircraft today. (The aileron was also invented independently by Robert Esnault-Pelterie.)

Bell experimented with box kites and wings constructed of multiple compound tetrahedral kites covered in silk. The tetrahedral wings were named Cygnet I, II and III, and were flown both unmanned and manned (Cygnet I crashed during a flight carrying Selfridge) in the period from 1907-1912. Some of Bell's kites are on display at the Alexander Graham Bell National Historic Site.


Other Inventions
Bell had made many other inventions in his life. They include the metal vacuum jacket that assists in breathing, the audiometer to detect minor hearing problems, a device that locates icebergs, investigated on how to separate salt from seawater, and also worked on finding alternative fuels.


Eugenics
Along with many very prominent thinkers and scientists of the time, Bell was connected with the eugenics movement in the United States. From 1912 until 1918 he was the chairman of the board of scientific advisors to the Eugenics Record Office associated with Cold Spring Harbor Laboratory in New York, and regularly attended meetings. In 1921 he was the honorary president of the Second International Congress of Eugenics held under the auspices of the American Museum of Natural History in New York. Organizations such as these advocated passing laws (with success in some states) that established the compulsory sterilization of people deemed to be, as Bell called them, a "defective variety of the human race." By the late 1930s about half the states in the US had eugenics laws, the California laws being used as a model for eugenics laws in Nazi Germany.

His ideas about people he considered defective centered on the deaf. This was due to his feelings for his deaf family and his contact with deaf education. In addition to advocating sterilization of the deaf, Bell wished to prohibit deaf teachers from being allowed to teach in schools for the deaf, he worked to outlaw the marriage of deaf individuals to one another, and he was an ardent supporter of oralism over sign language. His avowed goal was to eradicate the language and culture of the deaf so as to force them to assimilate into the hearing culture for their own long-term benefit and for the benefit of society at large. Although this attitude is widely seen as paternalistic and arrogant today, it was mainstream in that era. See also: audism.

Although he supported what many would consider harsh and inhumane policies today, he was not unkind to deaf individuals who supported his theories of oralism. He was a personal and longtime friend of Helen Keller (although she hated being deaf), and his wife Mabel was deaf, though none of their children were. Bell was known as a kindly father and loving family man who took great pleasure in playing with his many grandchildren.


Tributes
In the early 1970s, UK Rock Group The Sweet recorded a tribute to Bell and the telephone, suitably titled "Alexander Graham Bell". The song gives a fictional account of the invention, in which Bell devises the telephone so he can talk to his girlfriend who lives on the other side of the United States. The song reached the top 40 in the UK and went on to sell over one million recordings world-wide.

Another musical tribute to Bell was written by the British songwriter and guitarist Richard Thompson. The chorus of Thompson's songreminds the listener that "of course there was the telephone, he'd be famous for that alone, but there's fifty other things as well from Alexander Graham Bell". The song mentions Bell's work with discs rather than cylinders, the hydrofoil, Bell's work with the deaf, his invention of the respirator and several other of Bell's achievements.

Bell was honored on the television programmes the 100 Greatest Britons (2002), the 100 Greatest Americans (2005), and in the top ten Greatest Canadians (2004). The nominees and rankings for these programs were determined by popular vote. Bell was the only person to be on more than one of the programs.

Back