SEE ALSO Agriculture (c. 10,000 BCE) Ecological Interactions (1859), Photosynthesis (1947).
This World War II poster promotes the harvesting of legumes, which provide a food source and utilize atmospheric nitrogen to fertilize the soil.
1837
Telegraph System • Marshall Brain
Charles Wheatstone (1802–1875), William Fothergill Cook (1806–1879)
When we think of a telegraph system, we probably think of a person in an office tapping Morse code messages on a key, and receiving messages with a clicking metal bar. This arrangement, developed by English inventor William Fothergill Cook and scientist Charles Wheatstone in 1837, was the first telegraph implementation to be put into commercial service.
Many arrangements came before and after, but this one dominated for several reasons. Most importantly, it was incredibly simple. All you needed at each end was a key—essentially a switch—a sounder, an electromagnet that makes clicking noises, a single wire, and a battery. The earth was used as a second wire to complete the battery circuit. That simplicity meant it did not cost much to set up, and it was extremely reliable.
Once the basic system was in place, networks rapidly developed. The single wire had to go somewhere, and poles with glass insulators were the preferred place because they were inexpensive and easy to build. The poles went up along railroad tracks because it was an easy place to put them. Most train stations therefore had a telegraph office, and anyone in a town with a telegraph station could communicate with the rest of the world.
Imagine what would happen to a civilization that suddenly, for the first time, had the easy ability to communicate over long distances. A message that might have taken several days or a week to get through by letter on horseback could now get through in a minute.
During the Civil War, for example, the telegraph was a huge game changer for the North because messages could get to and from many battlefields almost instantly. President Lincoln himself could be found in the telegraph office getting instant information. It was much easier to move troops and supplies around with good communications in place.
Engineers found ways to insulate wires with gutta-percha and undersea telegraph cables soon followed. Engineers shrank the world.
SEE ALSO Olmec Compass (c. 1000 BCE) Telephone (1876), Radio Station (1920), ARPANET (1969).
A telegraph key. The telegraph represented an unprecedented ability to communicate over long distances.
1839
Daguerreotype • Derek B. Lowe
Nicéphore (Joseph) Niépce (1765–1833), Louis-Jacques-Mandé Daguerre (1787–1851)
The most famous form of applied photochemistry is photography. Adapting the camera obscura—a mechanical method of projecting an image using light, lenses, and mirrors—French inventor Nicéphore Niépce attempted to use chemicals to record what formerly required an artist’s eye and hand. In a process he called heliography (sun writing), Niépce coated a metal plate with the photosensitive agent bitumen (a tarry, naturally occurring petroleum fraction), positioned the plate in a camera obscura to receive the reflected image, and exposed it to sunlight for hours. Brightly lit areas hardened in the sun (probably via a free radical–induced polymerization), and unhardened, shaded areas were then washed away with a solvent, producing in 1826 the first permanent photographs. But because it required long hours of exposure, the technique was not a practical one.
French artist and photographer Louis-Jacques-Mandé Daguerre, who had been collaborating with Niépce, carried on after Niépce’s death, using as a light-sensitive agent the more promising silver compounds. After much experimentation, Daguerre produced metal plates coated with silver iodide, so light sensitive that several minutes of exposure were enough to produce an image. The plate was developed by exposure to mercury vapors, and the resulting image was composed of dark silver-mercury alloy (amalgam). But the plate was still light sensitive, and the unreacted silver iodide had to be removed to make the image permanent. Daguerre soon found that the final images could be tinted attractively (and made more durable) by a final exposure to gold salts.
The daguerreotype, revealed in 1839, was a sensation, especially when the process had improved enough for human portraiture. Still, the exposure times—between ten and sixty seconds—tended to produce rather a rather stiff appearance in the subjects, even under the best conditions. The whole procedure was difficult, expensive, and toxic. But it was the first, and it changed the world.
SEE ALSO Eyeglasses (1284), Telescope (1608), Hologram (1947).
LEFT: A daguerreotype of Daguerre himself, 1844. RIGHT: Foremen of the Phoenix Fire Company and the Mechanic Fire Company in Charleston, South Carolina, c. 1855.
1839
Rubber • Derek B. Lowe
Thomas Hancock (1786–1865), Charles Goodyear (1800–1860)
Rubber, a well-known example of a natural polymer, is built from molecules of isoprene, a five-carbon compound found in a variety of plants that is believed to protect them from heat stress. When isoprene is polymerized, the first product created is the sticky latex sap given off by plants such as the South American rubber tree.
This sap can be processed further to natural rubber—as it has been for hundreds of years in Central and South America—but natural rubber has a lot of limitations, among them its relentless stickiness in hot weather and its propensity to crack in the cold. Many inventors tinkered with it, trying to turn it into something more useful, and after many impoverished years of experimentation, American chemist Charles Goodyear famously succeeded. With the addition of sulfur and heat, he discovered, whether by accident or by design (one version has him sticking a lump of rubber to a hot stove), the rubber was cured into an elastic, durable, nonsticky substance that looked as if it would have huge potential, if it could be made industrially. More years of experimentation followed, with Goodyear stretching the patience of his family and his creditors. By 1844 he had filed for a patent for what would come to be known as the vulcanization (after the Roman god of fire) of rubber and had built a factory to produce goods made from it. There were still many wild swings in his fortunes as he fought patent disputes in Europe, most notably with English manufacturing engineer Thomas Hancock, who was simultaneously experimenting with rubber and had received a British patent for the same process.
Chemically, the sulfur in vulcanized rubber crosslinks the polymer chains, altering the properties of the material by changing the ways that the molecules can move relative to each other. Serendipitous or not, the vulcanization of rubber was a significant industrial and commercial advance, and today is responsible for consumer goods as varied as tires, hoses, shoe soles, and hockey pucks, as well as many parts of the industrial machinery involved in making them.
SEE ALSO Plastic (1856), Polyethylene (1933), Photosynthesis (1947).
Rubber-tree sap, harvested the old-fashioned way.
1841
Fiber Optics • Clifford A. Pickover
Jean-Daniel Colladon (1802–1893), Charles Kuen Kao (b. 1933), George Alfred Hockham (b. 1938)
The science of fiber optics has a long history, including such wonderful demonstrations as Swiss physicist Jean-Daniel Colladon’s light fountains in 1841, in which light traveled within an arcing stream of water from a tank. Modern fiber optics—discovered and independently refined many times through the 1900s—use flexible glass or plastic fibers to transmit light. In 1957, researchers patented the fiberoptic endoscope to allow physicians to view the upper part of the gastrointestinal tract. In 1966, electrical engineers Charles K. Kao and George A. Hockham suggested using fibers to transmit signals, in the form of light pulses, for telecommunications.
Through a process called total internal reflection, light is trapped within the fiber as a result of the higher refractive index of the core material of the fiber relative to that of the thin cladding that surrounds it. Once light enters the fiber’s core, it continually reflects off the core walls. The signal propagation can suffer some loss of intensity
over very long distances, and thus it may be necessary to boost the light signals using optical regenerators. Today, optical fibers have many advantages over traditional copper wires for communications. Signals travel along relatively inexpensive and lightweight fibers with less attenuation, and they are not affected by electromagnetic interference. Also, fiber optics can be used for illumination or transferring images, thus allowing illumination or viewing of objects that are in tight, difficult-to-reach places.
In optical-fiber communications, each fiber can transmit many independent channels of information via different wavelengths of light. The signal may start as an electronic stream of bits that modulates lights from a tiny source, such as a light-emitting diode or laser diode. The resultant pulses of infrared light are then transmitted. In 1991, technologists developed photonic-crystal fibers that guide light by means of diffraction effects from a periodic structure such as an array of cylindrical holes that run through the fiber.
SEE ALSO Newton’s Prism (1672), Wave Nature of Light (1801), Laser (1960).
Optical fibers carry light along their lengths. Through a process called total internal reflection, light is trapped within the fiber until it reaches the end of the fiber.
1842
General Anesthesia • Clifford A. Pickover
Frances Burney (1752–1840), Johann Friedrich Dieffenbach (1795–1847), Crawford Williamson Long (1815–1878), Horace Wells (1815–1848), William Thomas Green Morton (1819–1868)
In our modern world, we are likely to forget the horrifying realities of surgery before anesthesia. Fanny Burney, a famous nineteenth-century novelist and playwright, recounts the mastectomy she endured with only a glass of wine for the pain. Seven males held her down as the surgery began. She writes, “When the dreadful steel was plunged into the breast—cutting through veins-arteries-flesh-nerves—I needed no injunction not to restrain my cries. I began a scream that lasted unintermittently during the whole time of the incision. . . . Oh Heaven!—I then felt the knife racking against the breast bone—scraping it! This was performed while I yet remained in utterly speechless torture.”
General anesthesia is a state of unconsciousness induced by drugs, allowing a patient to undergo surgery without pain. Early forms of anesthesia date back to prehistoric times in the form of opium. Inca shamans used coca leaves to locally numb a site on the body. However, the discovery of general anesthesia suitable for modern operations is often attributed to three Americans: physician Crawford W. Long and dentists Horace Wells and William Morton. In 1842, Long removed a neck cyst while the patient inhaled ether, an anesthetic gas. In 1844, Wells extracted many teeth using nitrous oxide, commonly known as laughing gas. Morton is famous for his public demonstration of the use of ether in 1846 to assist a surgeon in removing a tumor from a patient’s jaw, and newspapers carried the story. In 1847, chloroform was also used, but it had higher risks than ether. Safer and more effective drugs are used today.
After Morton’s demonstrations, the use of anesthetics began to spread rapidly. In 1847, Johann Friedrich Dieffenbach, a pioneer in plastic surgery, wrote, “The wonderful dream that pain has been taken away from us has become reality. Pain, the highest consciousness of our earthly existence, the most distinct sensation of the imperfection of our body, must now bow before the power of the human mind, before the power of ether vapor.”
SEE ALSO Sutures (c. 3000 BCE) Paré’s “Rational Surgery” (1545), Heart Transplant (1967).
Three medical gases on a surgical room machine. Nitrous oxide (N2O) is sometimes used as a carrier gas in a 2:1 ratio with oxygen for more powerful general anesthesia drugs, such as desflurane or sevoflurane.
1843
Conservation of Energy • Clifford A. Pickover
James Prescott Joule (1818–1889)
“The law of the conservation of energy offers . . . something to clutch at during those late-night moments of quiet terror, when you think of death and oblivion,” writes science-journalist Natalie Angier. “Your private sum of E, the energy in your atoms and the bonds between them, will not be annihilated. . . . The mass and energy of which you’re built will change form and location, but they will be here, in this loop of life and light, the permanent party that began with a Bang.”
Classically speaking, the principle of the conservation of energy states that the energy of interacting bodies may change forms but remains constant in a closed system. Energy takes many forms, including kinetic energy (energy of motion), potential energy (stored energy), chemical energy, and energy in the form of heat. Consider an archer who deforms, or strains, a bow. This potential energy of the bow is converted into kinetic energy of the arrow when the bow is released. The total energy of the bow and arrow, in principle, is the same before and after release. Similarly, chemical energy stored in a battery can be converted into the kinetic energy of a turning motor. The gravitational potential energy of a falling ball is converted into kinetic energy as it falls. One key moment in the history of the conservation of energy was physicist James Joule’s 1843 discovery of how gravitational energy (lost by a falling weight that causes a water paddle to rotate) was equal to the thermal energy gained by water due to friction with the paddle. The First Law of Thermodynamics is often stated as: The increase in internal energy of a system due to heating is equal to the amount of energy added by heating, minus the work performed by the system on its surroundings.
Note that in our bow and arrow example, when the arrow hits the target, the kinetic energy is converted to heat. The Second Law of Thermodynamics limits the ways in which heat energy can be converted into work.
SEE ALSO Second Law of Thermodynamics (1850), & (1905), Energy from the Nucleus (1942).
This potential energy of the strained bow is converted to kinetic energy of the arrow when the bow is released. When the arrow hits the target, the kinetic energy is converted to heat.
1844
Transcendental Numbers • Clifford A. Pickover
Joseph Liouville (1809–1882), Charles Hermite (1822–1901), Ferdinand von Lindemann (1852–1939)
In 1844, French mathematician Joseph Liouville considered the following interesting number: 0.110001000000000000000001000. . ., known today as the Liouville constant. Can you guess its significance or what rule he used to create it?
Liouville showed that his unusual number was transcendental, thus making this number among the first to be proven transcendental. Notice that the constant has 1 in each decimal place corresponding to a factorial, and zeros elsewhere. This means that the 1s occur only in the 1st, 2nd, 6th, 24th, 120th, 720th, etc. places.
Transcendental numbers are so exotic that they were only “discovered” relatively recently in history, and you may only be familiar with one of them, π, and perhaps Euler’s Number, e. These numbers cannot be expressed as the root of any algebraic equation with rational coefficients. This means, for example, that π could not exactly satisfy equations like 2x4 − 3x2 + 7 = 0.
Proving that a number is transcendental is difficult. French mathematician Charles Hermite proved e was transcendental in 1873, and German mathematician Ferdinand von Lindemann proved π was transcendental in 1882. In 1874, German mathematician Georg Cantor surprised many mathematicians by demonstrating that “almost all” real numbers are transcendental. Thus, if you could somehow put all the numbers in a big jar, shake the jar, and pull one out, it would be virtually certain to be transcendental. Yet despite the fact that transcendental numbers are “everywhere,” only a few are known and named. There are lots of stars in the sky, but how many can you name?
Aside from his mathematical pursuits, Liouville was interested in politics and was elected to the French Constituting Assembly in 1848. After a later election defeat, Liouville became depressed. His mathematical ramblings became interspersed with poetical quotes. Nonetheless, during the course of his life, Liouville wrote more than 400 serious mathematical papers.
SEE ALSO π (c. 250 BCE), Euler’s Number, e (1727), Cantor’s Transfinite Numbers
(1874).
French mathematician Charles Hermite, c. 1887. Hermite proved in 1873 that Euler’s number e was transcendental.
1847
Semmelweis’s Hand Washing • Clifford A. Pickover
Ignaz Philipp Semmelweis (1818–1865), Louis Pasteur (1822–1895), Sir Joseph Lister (1827–1912)
Authors K. Codell Carter and Barbara Carter write, “Medical advances are purchased by two kinds of sacrifice: the sacrifice of researchers trying to understand disease and the sacrifice of patients who die or are killed in the process. [One] particular advance was purchased, in part, by the sacrifice of hundreds of thousands of young women who died, following childbirth, of a terrible disease known as childbed fever—a disease that was rampant in the charity maternity clinics of the early nineteenth century.”
Although several physicians had suggested the value of cleanliness in preventing infection even before microorganisms were discovered as causes of disease, the individual most famous for early systematic studies of disinfection was the Hungarian obstetrician Ignaz Semmelweis. Semmelweis noticed that the Vienna hospital in which he worked had a much higher rate of maternal mortality due to childbed fever than a similar hospital. He also noted that only in his hospital did physicians routinely study cadavers before examining patients.
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