Archives January 2014

Danish engineer Valdemar Poulsen (1869-1942) developed the first magnetic recording system. It was the direct antecedent of analog tape recording, the medium for which most audio was captured throughout the twentieth century. The operating principles differed little from later analog recording systems. A motorized assembly pulled a spool of hair-thin wire at a constant speed across a magnetic recording head. The sound intended for capture was converted to electrical pulses that were then fed through a record head that imposed a pattern of magnetization onto the wire analogous to the original signal. The spool was then rewound, and the wire passed across a playback head that detected changes in the magnetic field stored on the wire; these were converted back to a continuous electrical signal that could then be heard. Poulsen patented his Telegraphone in 1898. Two years later he took it to the World Exposition in Paris, where he more...

Wallace Carothers (1896-1937) was an excellent chemist and, as an undergraduate, was made head of the chemistry department at Tarkio College, Missouri. After becoming a professor at Harvard, he was lured into industry by chemical company DuPont, which had opened a science laboratory to develop new products. In 1928 he headed up a team looking into artificial materials. Carothers was interested in the hydrocarbon acetylene and its family of chemicals. After having developed the first synthetic rubber polymer—mass produced by DuPont as neoprene in 1931—he looked into creating a man-made synthetic fiber that could replace silk. Japan was the United States's main source of silk, but trade relations were breaking down as the political situation between the two countries worsened. Silk was becoming harder to source and very expensive. In 1935, Carothers made significant steps toward a silklike fiber by developing a chemical reaction between chemical units called monomers. The more...

"The person who has health has hope; and the person who has hope has everything." Arabic proverb Inspired by chicken incubators, which had been based on those depicted in Egyptian hieroglyphs, a French obstetrician by the name of Etienne Stephane Tarnier enlisted the help of a poultry raiser, Odile Martin, to construct incubators suitable for human infants. This 1880 adaptation of an ancient design has gone on to save millions of lives. The design was very simple: two chambers, one on top of the other with space for a baby in the upper chamber, and water heated by an oil lamp in the lower chamber. The lower chamber gently warmed the upper chamber whereas an opening in the uppermost compartment ensured that the infant could breathe. Since 1880 incubators have changed hugely with the modern version housing some of the most sophisticated equipment humans have devised. With around fourteen million more...

Dane Valdemar Poulsen (1869-1942) shaped a surprising amount of the modern world with the invention of magnetically recorded sound in 1898. It was an incredibly useful innovation that has been used in tape recordings, hard disks, floppy disks, and credit cards. It also led him to create, in 1904, the world's first "telephone answering device." Modern society relies on communication tools such as the telephone to function, and today it is very unusual to encounter a telephone that does not have some form of answering phone or voicemail. After its invention in 1876, the telephone became a world- changing tool, allowing anyone in the world to have a conversation with anyone else, immediately. It was only a matter of time before somebody had the idea for an answering machine. Poulsen's magnetic wire recording device was initially used in the answering machine but later versions used magnetic tape to record the more...

"We live in a changing universe, and few things are changing faster than our conception of it." Timothy Ferris, The Whole Shebang Bell Telephone Laboratories at Holmdel, New Jersey, was investigating the introduction of short-wave radio transatlantic telephone services, and was worried that static signals might interfere with voice transmission. In 1931 Bell physicist and engineer Karl Guthe Jansky (1905-1950) was instructed to find the source of the static. Using a high-quality 14.6 m (20.5 MHz) radio receiver and a quaint, wheel-mounted antenna system, he found three sources: nearby thunderstorms, distant thunderstorms, and a faint background hiss. The intensity of the latter varied daily. After a few months' work, Jansky realized that the period was not the solar day of twenty-four hours but the twenty- three hours fifty-six minutes sidereal day. By 1932 he had pinpointed the source of the hiss as being the Sagittarius region of the Milky Way more...

Aluminum has not always been the light, cheap metal it is now. Chemists once painstakingly toiled to produce even small amounts, largely because it quickly burned when heated to high temperatures. The Washington Monument was topped with aluminum at the end of its construction in 1884. The 6.1-pound (2.8 kg) pyramid was one of the biggest pieces created. In 1886, aluminum alchemists Charles Martin Hall and Paul Heroult discovered, independently, a process for cheap aluminum production. The twenty-two- year-olds, from the United States and France respectively, found that molten cryolite was the optimal environment for a chemical reaction to create large amounts of aluminum.                  Before being put through the Hall-Heroult process, bauxite ore must first be changed into aluminum-oxide. In the process, powdered aluminum oxide is dissolved in molten cryolite, a substance made up of sodium, aluminum, and fluoride. In the cryolite, more...

In 1870 nineteen-year-old Emile Berliner (1851-1929) left his native Germany and emigrated to the United States where he worked in a livery stable. There was nothing in his background or education—he had only the most rudimentary knowledge of electricity and physics—to suggest that he might have any impact on the emerging technology of the day. However, in 1876 he was so inspired by a demonstration of Alexander Graham Bell's telephone during the U.S. centennial celebrations that he decided to study the instrument. He discerned that its main weakness was the sound detector—the mouthpiece. The following year, working alone in his boarding house, Berliner created a new "loose contact" detector. This was arguably the earliest microphone because it increased the volume of the transmitted voice. At this time, Alexander Graham Bell, who had recently founded the Bell Telephone Company, became aware that a young unknown inventor had submitted a patent covering more...