| APRIL 15 - BIRTHS | |
| Robert L. Mills | |
(source) |
 Born 15
Apr 1927; died 27 Oct 1999.
American physicist who shared the 1980 Rumford Premium Prize with his colleague Chen Ning Yang for their "development of a generalized gauge invariant field theory" in 1954. They proposed a tensor equation for what are now called Yang-Mills fields. Their mathematical work was aimed at understanding the strong interaction holding together nucleons in atomic nuclei. They constructed a more generalized view of electromagnetism, thus Maxwell's Equations can be derived as a special case from their tensor equation. Quantum Yang-Mills theory is now the foundation of most of elementary particle theory, and its predictions have been tested at many experimental laboratories.«  50
Years Of Yang-Mills Theory, by Gerardus 't Hooft |
| Anthony F.C. Wallace | |
| Born 15
Apr 1923
Canadian-born American psychological anthropologist and historian known for his analysis of acculturation under the influence of technological change. |
|
| Nikolaas Tinbergen | |
(source) |
Born 15
Apr 1907; died 21 Dec 1988.
Dutch-born English ethologist, a zoologist who studied the behavior of animals in their natural habitats, who shared (with Konrad Lorenz and Karl von Frisch) the Nobel Prize for Physiology or Medicine in 1973 for "for their discoveries concerning "organization and elicitation of individual and social behaviour patterns." He is known for his long-term field observations of the social patterns, courtship and mating behaviour of seagulls, made in their natural habitat. Having constructed experiments to test sociobiological responses and animal aggression, he interpreted the results to explain that human violence is rooted in an animal instinct for survival. Though gulls were a primary interest, his diverse studies also encompassed sand wasps and stickleback fish.« Animal
in Its World: Field Studies, by Niko Tinbergen, Nikolaas
Tinbergen. |
| Samuel Kurtz Hoffman | |
| Born 15
Apr 1902
American propulsion engineer who led U.S. efforts to develop rocket engines for space vehicles. |
|
| Nikolay Nikolayevich Semyonov | |
| Born 15
Apr 1896; died 25 Sep 1986.
Soviet physical chemist who shared the 1956 Nobel Prize for Chemistry with Sir Cyril Hinshelwood for research in chemical kinetics. He was the second Soviet citizen (after the émigré writer Ivan Bunin) to receive a Nobel Prize. |
|
| Emory Leon Chaffee | |
| Born 15
Apr 1885; died 8 Mar 1975.
U.S. physicist known for his work on thermionic vacuum (electron) tubes. |
|
| Max Wertheimer | |
| Born 15
Apr 1880; died 12 Oct 1943.
Czech-born psychologist, one of the founders, with Kurt Koffka and Wolfgang Köhler, of Gestalt psychology, which attempts to examine psychological phenomena as structural wholes, rather than breaking them down into components. |
|
| George Harrison Shull | |
| Born 15
Apr 1874; died 28 Sep 1954.
American botanist and geneticist known as the father of hybrid corn (maize). As a result of his researches, corn yields per acre were increased 25 to 50 percent. He developed a method of corn breeding that made possible the production of seed capable of thriving under various soil and climatic conditions. |
|
| Johannes Stark | |
(EB) |
Born 15
Apr 1874; died 21 Jun 1957.
German physicist who won the 1919 Nobel Prize for Physics for his discovery in 1913 that an electric field would cause splitting of the lines in the spectrum of light emitted by a luminous substance; the phenomenon is called the Stark effect. |
| Conrad Hubert | |
(source) |
Born 15
Apr 1856; died 14 Mar 1928
(Akiba Horowitz) After emigrating from Russia to the U.S., he later founded the Everready Flashlight Co. He first developed electric novelties after receiving rights to the battery-powered lighted flowerpots invented by Joshua L. Cowen, and electrically illuminated scarf pins. In Mar 1898, he founded the American Electrical Novelty and Manufacturing Company to make bicycle lights. He then introduced the first tubular Flash Light (now known as a flashlight in the U.S. and a torch in Britain) based on the patent he bought from inventor David Misell (U.S. No 617,592 issued 10 Jan 1899). From his business activities, he became a millionaire. |
| Hermann Günther Grassmann | |
| Born 15
Apr 1809; died 26 Sep 1877.
German mathematician chiefly remembered for his development of a general calculus of vectors in Die lineale Ausdehnungslehre, ein neuer Zweig der Mathematik (1844; "The Theory of Linear Extension, a New Branch of Mathematics"). |
|
| Édouard Lartet | |
| Born 15
Apr 1801; died 28 Jan 1871.
Édouard Armand Isidore Hippolyte Lartet was a geologist, archaeologist, and a principal founder of paleontology, who is chiefly credited with discovering man's earliest art and with establishing a date for the Upper Paleolithic Period of the Stone Age. His most striking discovery was a mammoth tooth, found in a cave, upon which was a drawing of a mammoth. This was clear proof that man lived at the same time as the mammoth. |
|
| Sir James Clark Ross | |
| Born 15
Apr 1800; died 3 April 1862.
British naval officer who carried out important magnetic surveys in the Arctic and Antarctic and discovered the Ross Sea and the Victoria Land region of Antarctica. |
|
| Friedrich Georg Wilhelm von Struve | |
(source) |
Born 15
Apr 1793; died 23 Nov 1864.
German-Russian astronomer, one of the greatest 19th-century astronomers and the first in a line of four generations of distinguished astronomers. He founded the modern study of binary (double) stars. In 1817, he became director of the Dorpat Observatory, which he equipped with a 9.5-inch (24-cm) refractor that he used in a massive survey of binary stars from the north celestial pole to 15°S. He measured 3112 binaries - discovering well over 2000 - and cataloged his results in Stellarum Duplicium Mensurae Micrometricae (1837). In 1835, Czar Nicholas I persuaded Struve to set up a new observatory at Pulkovo, near St. Petersburg. There in 1840 Struve became, with Friedrich Bessel and Thomas Henderson, one of the first astronomers to detect parallax. |
| Walter Channing | |
| Born 15
Apr 1786; died 27 Jul 1876.
U.S. physician and one of the founders of the Boston Lying-In Hospital (1832), brother of the clergyman William Ellery Channing; he was the first (1847) to use ether as an anesthetic in obstetrics and the first professor of obstetrics at Harvard University (1815). |
|
| Étienne Geoffroy Saint-Hilaire | |
| Born 15
Apr 1772; died 19 Jun 1844.
French naturalist who established the principle of "unity of composition," postulating a single consistent structural plan basic to all animals as a major tenet of comparative anatomy, and who founded teratology, the study of animal malformation. |
|
| Charles Willson Peale | |
| Born 15
Apr 1741; died 22 Feb 1827.
American portrait painter and naturalist who opened the first U.S. popular Museum of Natural Science and Art. Alongside fame as a portraitist, Peale maintained a diverse interest in science. He used a physiognotrace machine used to record profiles and make silhouettes. He patented a fireplace, porcelain false teeth, and a new kind of wooden bridge. He invented a technique to put motion with pictures and wrote papers on engineering and hygiene. He perfected a kind of portable writing desk, named the polygraph, which reproduced several copies of a manuscript at once. In 1786, he established the first U.S. scientific museum with both living and stuffed specimens, and later a complete mastodon skelton he helped excavate (1801).« Mr.
Peale's Museum, by Charles Coleman Sellers. |
|
| William Cullen | |
(source) |
Born 15
Apr 1710; died 5 Feb 1790.
Scottish physician and chemist who held the first independent university lectureship designated for chemistry (founded 1747) in the British Isles at Glasgow University. The university also provided a modest sum for a laboratory. (An earlier chair at Edinburgh was entitled chemistry and medicine.) Cullen extended the subject of chemistry beyond medicine by connecting it to many "arts" including agriculture, bleaching, brewing, mining, and the manufacture of vinegar and alkalies. He moved to the University of Edinburgh in 1755. Cullen was active in the founding of the Royal Society of Edinburgh and the Royal Medical Society (Edinburgh). His sole paper (1756) was on his investigation of the cold produced by the evaporation of various fluids.*« |
| Leonhard Euler | |
| Born 15
Apr 1707; died 18 Sep 1783.
Swiss mathematician and physicist, one of the founders of pure mathematics. He not only made decisive and formative contributions to the subjects of geometry, calculus, mechanics, and number theory but also developed methods for solving problems in observational astronomy and demonstrated useful applications of mathematics in technology. At age 28, he blinded one eye by staring at the sun while working to invent a new way of measuring time. Euler:
The Master of Us All, by William Dunham |
|
| Leonardo Da Vinci | |
(source) |
Born 15 Apr 1452; died 2 May 1519.
Italian painter, draftsman, sculptor, architect, and engineer. Da Vinci was a great engineer and inventor who designed buildings, bridges, canals, forts and war machines. He kept huge notebooks sketching his ideas. Among these, he was fascinated by birds and flying and his sketches include such fantastic designs as flying machines. These drawings demonstrate a genius for mechanical invention and insight into scientific inquiry, truly centuries ahead of their time. His greater fame lies in being one of the greatest painters of all times, best known for such paintings as the Mona Lisa and The Last Supper.« [Image: Codex Leicester] |
| APRIL 15 - DEATHS | |
| Edwin J. Shoemaker | |
 Died
15 Apr 1998 (born 1907?)
American engineer and businessman whose invention of the recliner made the La-Z-Boy furniture company one of the most successful in the U.S. |
|
| Oscar Auerbach | |
| Died
15 Apr 1997 (born 1 Jan 1905)
American pathologist whose research showing that cigarette smoking was causally related to lung cancer, based on his examination of thousands of lung tissue samples. The work gained national prominence in the first Surgeon General's Report on Smoking and Health in 1964. |
|
| J. Tuzo Wilson | |
1989 (source) |
Died
15 Apr 1993 (born 24 Oct 1908)
Canadian geologist and geophysicist who established global patterns of faulting and the structure of the continents. Wilson did much to establish the new discipline of plate tectonics during the early 1960s and was the first to use the term 'plate' to refer to the rigid portions (oceanic, continental, or a combination of both) into which the Earth's crust is divided. In 1963 he produced some of the earliest evidence in favour of the sea-floor spreading hypothesis of Harry H. Hess when he pointed out that the further away an island lay from the mid-ocean ridge the older it proved to be. In 1965, he introduced the new concept of a transform fault where plates slide past each other without any creation or destruction of material. |
| Alfred Church Lane | |
| Died
15 Apr 1948 (born 29 Jan 1863)
U.S. geologist and educator who originated, promoted, and directed research on the determination of the age of the Earth. He was petrographer, assistant state geologist, and state geologist for the Michigan State Geological Survey from 1889 to 1909. |
|
| Charles Fredrick Cross | |
| Died
15 Apr 1935 (born 11 Dec 1855)
English chemist who, with Edward Bevan and Clayton Beadle, discovered cellulose could be produced (1891) by the dissolution of cellulose xanthate in dilute sodium hydroxide. Although cellulose had previously been made by others, this type of cellulose is the most popular type in use today. It was a syrupy yellow liquid. In 1892, Cross worked out a method for dissolving cellulose in carbon disulphide (producing a solution he called viscose) which could be squirted out of fine holes. As the solvent evaporated, a fine fibre was formed which became known as viscose rayon (or simply viscose). By 1908, the viscose was also used extruded through a narrow slit to produce thin, transparent sheets of cellophane. |
|
| Jean-Charles-Galinard de Marignac | |
(source) |
Died
15 Apr 1894 (born 24 Apr 1817)
Swiss chemist whose life work consisted of making many precise determinations of atomic weights suggested the possibility of isotopes and the packing fraction of nuclei. He began a study of the rare-earth elements in 1840, when barely 23 years old. In 1878, he heated until it decomposed some erbium nitrate obtained from gadolinite. Extracting the product with water he obtained two oxides: a red one he named erbia and a colourless one he named ytterbia. Thus he discovered ytterbium, and later was a codiscover of gadolinium (1880). By separating tantalic and columbic acids, he also proved that tantalum and colubium (niobium) were not identical. The last 10 years of his life he lay prostrate, suffering intensely from heart disease. |
| Christopher Hansteen | |
(source) |
Died
15 Apr 1873 (born 26 Sep 1784)
Norwegian astronomer and physicist noted for his research in geomagnetism. In 1701 Halley had already published a map of magnetic declinations, and the subject was studied by Humboldt, de Borda, and Gay-Lussac, among others. Hansteen collected available data and also mounted an expedition to Siberia, where he took many measurements for an atlas of magnetic strength and declination. |
| Thomas Drummond | |
(source) |
Died
15 Apr 1840 (born 10 Oct 1797)
Scottish civil engineer who invented the Drummond light (similar to limelight illumination in theatres). As a Royal Engineer he worked on the ordnance survey and attended chemistry lectures by Faraday at the Royal Institution. In the autumn of 1825, while mapping Ireland, Drummond applied limelight to enable surveying by night as well as day and designed an improved Heliostat. To produce a bright light, using an oxygenated alcohol flame, he heated a small ball of lime to incandescent in front of a reflector. From 1828, he attempted to adapt the Drummond light for use in lighthouses, but it was expensive to operate, and by 1831, he instead turned to politics, and by 1835 was Under Secretary of Ireland. His early death was caused by overwork.« 
Thomas
Drummond: Under-secretary in Ireland, 1835-40; life and letters,
by R. Barry O'Brien. |
| John Bell | |
(source) |
Died
15 Apr 1820 (born 12 May 1763)
Scottish surgeon, anatomist and artist. His anatomical etchings are harshly realistic because he criticized the approach of artists in his day to beautify the body and their "vitious practice of drawing from imagination." He believed that unlike the painter "striving for elegance of form" the anatomist must focus on "accuracy of representation." Bell began his medical training at age 17 (1779) in Edinburgh. By 1790, Bell set up his own anatomy school to present the subject more effectively for the practicing surgeon than offered at the established Royal Infirmary. Meeting opposition from other surgeons caused by his outspokenness, he ceased teaching after 13 years, and for the next 20 years limited himself to surgical practice and consulting.« |
| Oliver Evans | |
(source) |
Died
15 Apr 1819 (born 13 Sep 1755)
American millwright and inventor who invented the first automatic corn mill, pioneered the high-pressure steam engine (US patent, 1790) and created the first continuous production line (1784). By about age 19, he invented a machine for bending and cutting off the wires in textile carding combs. His ideas for an automatic corn mill began in 1782, but the invention's development was not completed until 1790. The mill used bucket elevators to raise the grain, conveying devices including a horizontal screw conveyor, and a "hopper boy" to cool and dry the meal before gathering it into a hopper feeding the bolting cylinder. Together, this took incoming wheat and delivered flour packed in barrels. |
| Mikhail Vasilyevich Lomonosov | |
| Died
15 Apr 1765 (born 19 Nov 1711)
Russian poet, scientist, and grammarian who is often considered the first great Russian linguistic reformer. He also made substantial contributions to the natural sciences, reorganized the St. Petersburg Imperial Academy of Sciences, and established in Moscow the university that today bears his name. |
|
| Johan van Waveren Hudde | |
| Died
15 Apr 1704 (born 23 Apr 1628)
Dutch mathematician and statesman who promoted Cartesian geometry and philosophy in Holland and contributed to the theory of equations. |
|
| Filippo Brunelleschi | |
| Died
15 Apr 1446 (born 1377)
architect and engineer who was one of the pioneers of early Renaissance architecture in Italy. His major work is the dome of the Florence Cathedral (1420-36), constructed with the aid of machines that Brunelleschi invented expressly for the project. |
|
| APRIL 15 - EVENTS | |
| First British bionic eye implant | |
In 2008, the first procedure
in Britain to implant
"bionic" eyes was carried out at Moorfields Eye Hospital, London, on two
blind patients with retinal pigmentosa but intact optic nerves. In 4-hr
operations, surgeons implanted a tiny electrode panel into the back of
the eye and an ultra-thin receiver under the skin near the ear to pick
up a wireless signal from a tiny camera on sunglasses and a signal processor
worn on a belt. The patients can then perceive an array of spots of light
showing crude shapes and movements. This international test with three
other European hospitals followed clinical trials around the U.S. by the
Californian firm, Second Sight, founded
in 1998 to develop the Argus II retinal implant.« |
|
| 3D X-rays | |
|
In 1966, the first X-ray three-dimensional stereo fluoroscopic system was
installed for use in heart catherization by Richard J Kuhn. The $30,000
machine, developed by Joseph Quinn was put into use at the University of
Oregon Medical Center, Portland, Oregon, U.S. The X-ray tube had
one anode but two cathodes, an image intensifier with polarizers, and a
synchronized analyzer. This produced a 3D image that could be seen through
a viewing mirror without the use of special glasses. |
|
| Chesapeake Bay Bridge | |
|
In 1964, Chesapeake Bay Bridge opened, the longest in the world at 17½
miles. |
|
| Hydrogen thryatron | |
|
In 1952, the hydrogen thryatron was patented in the U.S. by K. Germeshausen
(No. 2,591,556). The thryatron is an electronic switching tube filled with
gas. Application of a voltage to the control grid turns on the current.
It is normally used for high voltage switches. |
|
| One-hour helicopter flight | |
 |
In 1941, Igor Ivor Sikorsky made the first helicopter flight over one-hour
duration in his Vought-Sikorsky VS-300. It used a three-bladed main propeller
28-feet in diameter, and stayed in the air for 65 minutes and 14.5 seconds. |
| Hammond organ | |
(source) |
In 1935, the first pipeless organ was exhibited at the Industrial Arts
Exhibition, New York City in Radio City's RCA Building. Pietro A. Yon,
organist of St. Patrick’s Cathedral, and Fritz Reiner, who later became
conductor of the Chicago Symphony Orchestra, took turns at the keyboard.
When George Gershwin performed on the new instrument, he was so impressed
that he immediately ordered one. Critical acclaim at the debut was virtually
unanimous. It was the invention of Laurens
Hammond, patented 24 Apr 1934,
and made by the Hammond Clock Company. The organ had two manuals and pedals,
and weighed 275 pounds. The vast range of sounds it could produce contributed
its success despite its $1,250 price.« |
| Insulin | |
(source) |
In 1923, insulin became generally available for diabetics' use on this
day. It was first discovered in 1922. Today, insulin, is used daily in
the treatment of diabetes. Insulin, a natural and vital hormone for carbohydrate
metabolism in the body, is manufactured by the pancreas. An overabundance
of insulin causes insulin shock and leads to a variety of symptoms, including
coma. It is extracted from the pancreas of sheep, oxen and other means,
including synthesis in the laboratory. |
| Birdman of Alcatraz | |
 |
In 1920, Robert Stroud, the "Birdman of Alcatraz", was able to continue
his research into bird diseases in prison, when President Woodrow Wilson
commuted his death sentence. |
| Fourth dimension | |
|
In 1912, the fourth dimension was spoken of by Einstein as time. |
|
| Balmer series | |
|
In 1895, a mathematical relationship between the frequencies of the hydrogen
light spectrum was reported by a Swiss school teacher, Johann Balmer, in
Annalen
der Physik. Its significance was overlooked until Niels Bohr realized
this showed a structure of energy levels of the electron in the hydrogen
atom. |
|
| General Electric Company incorporated | |
|
In 1892, the General Electric Company, formed by the merger of the Edison
Electric Light Co. and other firms, was incorporated in New York state. |
|
| Ivory soap | |
|
In 1878, Harley Procter developed Ivory Soap, which when marketed later,
made Procter and Gamble a multi-million dollar business. |
|
| Helicopter | |
|
In 1877, a steam-engine driven helicopter
model built by Enrico Forlanini rose 40 ft (12 m). The machine
weighed 3.5 kg (7.7 lbs). Its coaxial rotors were powered by a two-cylinder
steam engine. Just before takeoff the spherical steam accumlator was charged
with 10 atmospheres of pressure, enabling the craft to rise and remain
aloft for 20 seconds. Forlanini (1848-1930) was an Italian pioneer of scientific
aviation. He built a hydroplane, which could take off on water (1905) and
a new type of semirigid aircraft in1914. He also invented the hydrofoil
boat. Alexander Graham Bell secured
the Italian’s patents to pursue his own interest in hydrofoil development. |
|
| First state entomologist | |
|
In 1854, the state of New York was the first American state to finance
the study of insects harmful to plants when $1,000 was budgeted by the
legislature for research. The following month, Asa Finch became the country's
first publicly funded entomologist. His first report (1855) covered fruit-damaging
insects. |
|
| Erie Canal | |
|
In 1817, the Erie Canal was authorized. It was the first canal of
importance in the U.S. and linked Buffalo on Lake Erie with the Hudson
River at Albany New York, a distance of 360 miles. |
|
| Water powered U.S. worsted mill | |
|
In 1788, a water-powered worsted mill was opened in Hartford, Conn., made
possible by subscriptions from nearby towns contributing a capital of 1,250
pounds. The Hartford Woolen Manufactory was the first U.S. worsted mill
to use water power, and was the first strictly commercial worsted mill.
Worsted yarns are more tightly twisted than are the bulkier woolen yarns.
Water power had previously been used by American fulling mills in the shrinking
and thickening of cloth. |
|
| Eraser | |
|
In 1770, Dr. Joseph Priestley
made the first mention in English that a piece of a rubber substance could
erase marks from black-lead pencils. At the end of the Preface to his work,
Familiar
Introduction to the Theory and Practice of Perspective, he described
it: "Since this Work was printed off, I have seen a substance excellently
adapted to the purpose of wiping from paper the mark of a black-lead-pencil.
It must, therefore, be of singular use to those who practise drawing. It
is sold by Mr Nairne, Mathematical Instrument Maker, opposite the Royal
Exchange. He sells a cubical piece of about half an inch for three shillings;
and he says it will last several years."*
Joseph
Priestley: Adventurer in Science and Champion of Truth,
by F W. Gibbs. |
|
| Isaac Newton's apple | |
|
In 1726, writer William Stukeley held a conversation
with Newton in Kensington during which Newton recalled "when formerly,
the notion of gravitation came into his mind." Later, Stukeley writing
in his Memoirs of Sir Isaac Newton's Life, recorded that Newton
said, "It was occasioned by the fall of an apple, as he sat in contemplative
mood. Why should that apple always descend perpendicularly to the ground,
thought he to himself. Why should it not go sideways or upwards, but constantly
to the earth's centre." |
|
| Surgery book | |
(source) |
In 1561, Ambroise Paré published
Anatomie
universelle du corps humain (Universal anatomy of the human body")
based on the authoritative work on anatomy written by Belgian anatomist
Andreas Vesalius (1514-1564). Paré had decided to publish this small
handbook of anatomy, written in French (he couldn't read Latin) to make
the knowledge accessible for study by surgeon-barbers. Although the French
translation of Estienne (1546) was otherwise available, it was of a large
size and very expensive. Paré's own important contributions included
reintroducing the midwifery technique of podalic version. The 49 wood engravings
of anatomy encompassed both some inspired by Vesalius, and illustrations
of Paré's own innovations.
Ambroise
Pare: Surgeon of the Renaissance, by Wallace B. Hamby. |
| See 16 Apr 1756 for the date of death of Jaccques Cassini, although 15 Apr 1756 is given by Dictionary of Scientific Biography. More in this note.] | |
