| APRIL 21 - BIRTHS | |
| Michael Hartley Freedman | |
(source) |
 Born 21
Apr 1951
American mathematician who was awarded the Fields Medal in 1986 for his proof of the conjecture in four dimensions (1982). The Poincaré conjecture, one of the famous problems of 20th-century mathematics, asserts that a simply connected closed 3-dimensional manifold is a 3-dimensional sphere. The higher dimensional Poincaré conjecture claims that any closed n-manifold which is homotopy equivalent to the n-sphere must be the n-sphere. For values of n at least 5, a solution was given by Smale in 1961. Two decades later, Freedman proved the conjecture for n = 4. However, the original conjecture for n=3 the remained open. Grigori Perelman is thought to have recently proved this remaining case of n=3.« |
| Garrett Hardin | |
|
(source) |
Born 21
Apr 1915; died 14 Sep 2003.
American biologist and author known for his classic essay on ecology and social ethics Tragedy of the Commons (published in Science, 13 Dec 1968), a parable about farmers who, allowed to graze their cattle in one field as much as they wanted to, each acted in their own self-interest, and the field was destroyed. He extended the idea of self-interest beyond the individual to households, villages, companies or nations. His concept of the commons includes ecosystems, rivers, oceans, organisms or mineral resources with actions such as over-fishing, deforestation and greenhouse gas emissions. He concluded that the Earth will likewise be destroyed by overpopulation. Hardin was a founding member of Planned Parenthood. He died by suicide.« |
| Choh-hao Li | |
(source) |
Born 21
Apr 1913; died 28 Nov 1987.
Chinese-American biochemist and experimental endocrinologist who with his co-workers isolated in pure form six of the eight hormones known to be secreted by the anterior pituitary gland. Located at the base of the brain, its homones govern reproduction, growth, maturation, and metabolism. Among the hormones Li isolated are ACTH(the adrenocorticotropic hormone and adrenal booster, used in the treatment of arthritis) and HGH (the human growth hormone or somatotropin, which is vital for human growth). He also discovered ß-endorphin, a naturally secreted painkiller (1976) and was first to synthesize the insulin-like growth factor 1, which promotes the growth of cartilage and bones. He was the first to synthesize HGH, in 1970. |
| Dr. Rollo May | |
(source) |
Born 21
Apr 1909; died 22 Oct 1994
American psychologist. May is the best known American existential psychologist. Much of his thinking can be understood by reading about existentialism in general, and the overlap between his ideas and the ideas of Ludwig Binswanger is great. Nevertheless, he is a little off of the mainstream in that he was more influenced by American humanism than the Europeans, and more interested in reconciling existential psychology with other approaches, especially Freud’s. In 1958, he edited, with Ernest Angel and Henri Ellenberger, the book Existence, which introduced existential psychology to the US. |
| Paul Karrer | |
(source) |
Born 21
Apr 1889; died 18 June 1971.
Swiss chemist who investigated the constitution of carotenoids, flavins, and vitamins A and B2, for which he shared the 1937 Nobel Prize for Chemistry (with Sir Norman Haworth of Great Britain). He studied plant pigments, particularly the yellow carotenoids, which are related to the pigment in carrots. He determined the chemical structure of the carotenoids (1930), showed that some of these substances are transformed into vitamin A in the animal body, then determined the structure of vitamin A itself. He also confirmed the constitution of vitamin C proposed by Albert Szent-Györgyi, showed lactoflavin to be part of the complex originally described as vitamin B2 , and studied vitamin E. |
| Percy Williams Bridgman | |
(source) |
Born 21
Apr 1882; died 20 Aug 1961.
American experimental physicist noted for his studies of materials at high temperatures and pressures.He was awarded the Nobel Prize for Physics in 1946 for his "invention of an apparatus to produce extremely high pressures, and for the discoveries he made therewith in the field of high pressure physics." He was the first Harvard physicist to receive a Nobel Prize in Physics. His first experimental work on static high pressures beginning in 1908 at first yielded pressures of about 6,500 atmospheres. Eventually, he reached about 400,000 atmospheres. During studies of the phase changes of solids under pressure, he discovered several high-pressure forms of ice. Bridgman also wrote eloquently on matters of general interest in the physics of his day. |
| Sir Herbert Atkinson Barker | |
1908 (source) |
Born 21 Apr 1869; died 21 July 1950.
English osteopath and manipulative surgeon, who treated knee pain and cartilage problems in top sports players as well as the general public. Barker treated patients on his yacht in the Channel Isles. He maintained that a knee cartilage operation was unnecessary in a very large proportion of cases and he claimed that manipulation was sufficient without any surgery. The community of Montego Bay, Jamaica, credits the genesis of its tourist trade to the famous chiropractor Sir Herbert Barker in England because he promoted the sea water as having curative powers at the Doctor's Cave bathing club there. (That site had been donated it to the town in 1906 for that purpose by the eccentric physician, Dr. Alexander McCatty.)« [Image right (source) ] |
| Oskar Hertwig | |
(source) |
Born 21
Apr 1849; died 25 Oct 1922
Oskar (Wilhelm August) Hertwig was a German embryologist and cytologist who did extensive work on the nuclear transmission of heredity. He was the first to recognize that the essential event in fertilization is the fusion of the nuclei of the sperm and ovum. In 1875, he observed all the steps in fertilization, including the union of egg and sperm chromosomes in sea urchins. These animals are particularly suitable for microscopic studies because of their transparency. He saw there was a single nucleus before fertilization and two nuclei immediately afterwards. He realized the second nucleus had come from the spermatazoon, and thus a single spermatazoon can fertilize an egg. He also investigated malformations of vertebrate embryos. |
| Walther Flemming | |
(source) |
Born 21
Apr 1843; died 4 Aug 1905.
German anatomist who was the first to observe and describe systematically the behaviour of chromosomes in the cell nucleus during normal cell division (mitosis, a term he coined in 1882). Thus, he was a founder of cytogenetics as a branch of science to study chromosomes, the cell's hereditary material. Flemming coined other terms: spireme, aster, chromatin, achromatin, monocentric and dicentric phases. Chromatin (Gr. chroma = colour) referred to certain fragments of the cell nucleus that took on a strong colour from the dyes he used during microscopic study. Flemming did not know of Mendel's work, so 20 years passed before the genetic implications were realized. Chromosomes, formed from cromatin, were named in 1888 by Waldeyer-Hartz. |
| John Muir | |
Yosemite 1907 (source) |
Born 21
Apr 1838; died 24 Dec 1914.
Scottish-American naturalist, farmer, explorer, writer, conservationist, who championed the establishment of Sequoia and Yosemite national parks in California. In 1849, the Muir family emigrated to the U.S. As an inventor, he carved clocks and curious but practical mechanisms (like a device that tipped him out of bed before dawn), that won Wisconsin State Fair prizes (1860). He had begun travelling the U.S. by 1867. His later years he wrote extensively: 300 articles and 10 major books that recounted his travels, his beloved Sierra Nevada, and expounded his naturalist philosophy. Muir drew attention to the devastation of mountain meadows and forests by sheep and cattle, leading to his role as "Father of the National Park System "  John
Muir: The Eight Wilderness Discovery Books, by John Muir |
| James Starley | |
age 23 (source) |
Born 21
Apr 1830; died 17 Jun 1881.
British inventor and manufacturer, known as the father of the bicycle industry. Starley left the family farm as a teenager and after initially working as a gardener, he turned to mechanical interests. He improved the early sewing machine, and by about 1861, was in business with Josiah Turner as the Coventry Sewing Machine Company. Within a few years, their factory began producing bicycles. In 1870, he went into business for himself, producing his Europa sewing machines and Ariel bicycles, "penny-farthing" and tricycles. The Ariel, a lightweight all-metal bicycle (1871), is regarded as the first true bicycle, the first self-propelled two-wheeler to use pivot-center steering. His tangent-tension spoke wheel (1876) is still used.« |
| Jean-Baptiste Biot | |
(source) |
Born 21
Apr 1774; died 3 Feb 1862.
French mathematician and physicist who co-developed the Biot-Savart law, that the intensity of the magnetic field produced by current flow through a wire varies inversely with the distance from the wire. He did work in astronomy, elasticity, heat, optics, electricity and magnetism. In pure mathematics, he contibuted to geometry. In 1804 he made a 13,000-feet (5-km) high hot-air balloon ascent with Joseph Gay-Lussac to investigate the atmosphere. In 1806, he accompanied Arago to Spain to complete earlier work there to measure of the arc of the meridian. Biot discovered optical activity in 1815, the ability of a substance to rotate the plane of polarization of light, which laid the basis for saccharimetry, a useful technique of analyzing sugar solutions.« |
|
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| APRIL 21 - DEATHS | |
| R.B. Braithwaite | |
(source) |
 Died
21 Apr 1990 (born 15 Jan 1900)
Richard Bevan Braithwaite was a British philosopher, who trained in physics and mathematics, but turned to the philosophy of science. He examined the logical features common to all the sciences. Each science proceeds by inventing general principles from which are deduced the consequences to be tested by observation and experiment. Braithwaite was concerned with the impact of science on our beliefs about the world and the responses appropriate to that. He wrote on the statistical sciences, theories of belief and of probability, decision theory and games theory. He was interested in particular with the laws of probability as they apply to the physical and biological sciences.« Scientific
Explanation: A Study of the Function of Theory, Probability and Law in
Science, by R.B. Braithwaite. |
| Aleksandr Oparin | |
1970 (EB) |
Died
21 Apr 1980 (born 18 Feb 1894)
Russian biochemist noted for his studies on the origin of life from chemical matter. By drawing on the insights of chemistry, he extended the Darwinian theory of evolution backward in time to explain how simple organic and inorganic materials might have combined into complex organic compounds. In 1938, Oparin suggested that organic molecules could be formed in the presence of outside energy sources. The
Origin of Life, by Aleksandr Ivanovich Oparin. |
| André-Louis Danjon | |
(source) |
Died
21 Apr 1967 (born 6 Apr 1890)
French astronomer who devised a now standard five-point scale for rating the darkness and colour of a total lunar eclipse, which is known as the Danjon Luminosity Scale. He studied Earth's rotation, and developed astronomical instruments, including a photometer to measure Earthshine - the brightness of a dark moon due to light reflected from Earth. It consisted of a telescope in which a prism split the Moon's image into two identical side-by-side images. By adjusting a diaphragm to dim one of the images until the sunlit portion had the same apparent brightness as the earthlit portion on the unadjusted image, he could quantify the diaphragm adjustment, and thus had a real measurement for the brightness of Earthshine.« |
| Sir Edward Appleton | |
(source) |
Died
21 Apr 1965 (born 6 Sep 1892)
Sir Edward (Victor) Appleton, was an English physicist who won the 1947 Nobel Prize for Physics for his discovery of the Appleton layer of the ionosphere. From 1919, he devoted himself to scientific problems in atmospheric physics, using mainly radio techniques. He proved the existence of the ionosphere, and found a layer 60 miles above the ground that reflected radio waves. In 1926, he found another layer 150 miles above ground, higher than the Heaviside Layer, electrically stronger, and able to reflect short waves round the earth. This Appleton layer is a dependable reflector of radio waves and more useful in communication than other ionospheric layers that reflect radio waves sporadically, depending upon temperature and time of day.« Sir
Edward Appleton, by Ronald William Clark. |
| Sir Frederick Handley Page | |
 |
Died
21 Apr 1962 (born 15 Nov 1885)
British aircraft designer who built the Handley Page 0/400, the world's first twin-engine bomber for the Royal Flying Corps, one of the largest planes used in WW I, which carried out their first large-scale bombing raids on enemy military installations and submarine bases in Nov 1916. By 1918, he had produced a four-engine bomber that could attack the industrial zones of the Saar and the Ruhr in Germany. In 1930, he produced the first 40-seat civilian airliner, the Hercules. For WW II, Page returned to producing military aircraft, the most important being the Halifax bomber. The government purchased 7,000 of these planes. He was knighted for his contribution to the war effort. After the war Page designed the four-engine jet bomber, the Victor. |
| Sir John Graham Kerr | |
(source) |
Died
21 Apr 1957 (born 18 Sep 1869)
English embryologist whose research advanced knowledge of the evolution of vertebrates. He also promoted ideas in naval camouflage for WWI. Early in his career, pursuing his zoological interests, Kerr went on two expeditions to the Pilcomayo River in South America. Much of his subsequent research was based on samples collected during these expeditions. In a letter to Winston Churchill, dated 24 Sep 1914, he referred to observing animal camouflage in South America, and recommended painting war ships with graduated shading. He also communicated with Ernest Bevin and Clement Atlee and others concerning camouflage. Although sometimes credited with invention of the dazzle scheme of camouflage, his ideas were less extreme.« |
| Sir Henry Christopher Mance | |
(source) |
Died
21 Apr 1926 (born 1840)
British scientist and engineer whose invention of a heliograph provided a portable signaling device that used a tripod with a mirror to reflect sunlight (British patent Feb 1876). A second mirror could direct sunlight onto the first which was tilted using a telegraph-type finger key to transmit a coded series of short and long flashes to a distant station, up to 100 miles away. After its successful use in the second Anglo-Afghan War (1878-80), it became an important part of British military communications. Mance worked for the Persian Gulf Telegraph Department in India from 1863, and helped lay the first submarine telegraph cables in the Persian Gulf. He invented the Mance method to detect defects in submarine cables and locate their position.« |
| Alfred Elis Törnebohm | |
(source) |
Died
21 Apr 1911 (born 16 Oct 1838)
Swedish geologist and pioneer in the study and analysis of mountain structure. In 1888, he presented the first outlines of his theory of the overthrust of the Caledonian Range (the mountainous region in northwestern Europe extending from the British Isles to western Scandinavia) onto a foreland to the southeast and demonstrated (1896) that the overthrusting applied to the entire mountain range and exceeded 80 miles (130 km). He illustrated his completed description with a map of a 36,000-square-mile (93,000-square-kilometre) area. |
| Samuel Slater | |
(source) |
Died
21 Apr 1835 (born 9 June 1768)
English-American mechanical engineer who founded the American cotton-textile industry. Before he left Nottingham and immigrating to the U.S. in 1789, Slater apprenticed with Jedediah Strutt (partner of Richard Arkwright) in England. Once in the U.S., he found backing to build Arkwright’s spinning and carding machinery, with which he established the first successful cotton mill in the U.S. in Pawtucket, Rhode Island, as well as many others in the New England region.  Memoir
of Samuel Slater, the Father of American Manufactures, by
George White |
| Johann Friedrich Pfaff | |
(source) |
Died
21 Apr 1825 (born 22 Dec 1765)
German mathematician who proposed the first general method of integrating partial differential equations of the first order. Pfaff did important work on special functions and the theory of series. He developed Taylor's Theorem using the form with remainder as given by Lagrange. In 1810 he contributed to the solution of a problem due to Gauss concerning the ellipse of greatest area which could be drawn inside a given quadrilateral. His most important work on Pfaffian forms was published in 1815 when he was nearly 50, but its importance was not recognised until 1827 when Jacobi published a paper on Pfaff's method.« |
| John Michell | |
(source) |
Died
21 Apr 1793 (born 1724)
British geologist and astronomer who was the first to devise a realistic estimate of the distance to the stars, discovered physical double stars, and is considered the father of seismology. After the Lisbon earthquake of 1755 (which killed 70,000 people), he suggested that earthquakes set up wave motion in the earth. He noted the increased frequency of earthquakes in volcanic areas. Michell realized that by comparing the time at which earthquakes are felt, the epicentre could be calculated. He invented a torsion balance, a device to measure very small forces, though died before carrying out its purpose to determine the density of the Earth. His rebuilt apparatus was used by Cavendish to make that measurement, which also gives the gravitational constant).« [Image: Michell torsion balance as used by Cavendish] |
| APRIL 21 - EVENTS | |
| Revolving restaurant | |
1962 (source) |
In 1962, the Seattle World's Fair on a 74-acre site, Seattle, Washington,
was opened by remote control by President John F. Kennedy from Palm Beach,
Florida. The Space Needle - a 600-ft steel and glass tower - was erected
as its dominant central structure. When built in 1962, it was the tallest
building west of the Mississippi River. The first revolving restaurant
in the mainland U.S., the "Eye of the Needle," was located at the 500-ft
level. A 14-foot ring next to the windows carrying 260 seats rotates 360
degrees in one hour on a track and wheel system driven by a 1 horsepower
motor. The restaurant is now named SkyCity.« [Image
from a postcard.] |
| Firehouse pole | |
(source) |
In 1878, the first U.S. firehouse pole was installed
in New York City, by Capt. David B. Kenyon to reduce the time for men to
travel to the ground floor from the second floor at Engine Company 21*.
Fire stations had added a second floor for a sleeping and relaxation area.
Although some stations had sliding chutes, Kenyon thought a pole would
be faster. With the chief's permission, a hole was cut in the floor for
a 3-inch diameter wooden pole, which Kenyon had sanded carefully and oiled.
Following its success, In 1880, the first brass pole was installed
in Worchester, Mass. by Charles Allen of Engine Company No. 1.« [Image:
Fireman ready to slide down the pole in the dormitory of Fire Hall No.
7, Calgary, Alberta, c.1910] |
| Bustle | |
(USPTO) |
In 1857, the first U.S. patent for a bustle was issued to Alexander Douglas
(No. 17,082). The design had adjustments so that the size could be increased
or decreased. It described the construction of the bustle from elastic
material such as strips of whalebone and strips of flexible material such
as cloth or corset lacing, attached to the whalebone. "When in use the
flexible part adapts itself to the form of the wearer and the elastic strips
stand out therefrom." To make "the magnitude of the bustle adjustable at
pleasure simply by shortening or lengthening the flexible parts," eyelets
were provided at the extremities of the strips threaded in the same manner
as corset lacings. By changing the length of the lacing, the wearer could
adjust the size of the bustle.« |
| Scottish fire brigade | |
|
In 1703, Edinburgh Fire Brigade, one of the first in Scotland, was formed. |
|
