April
Important dates in History
April
30: Electric Company
In
1883, the first U.S. three-wire central station for incandescent lighting was
incorporated. The plant was in Sunbury, Pennsylvania.
April
29: Wallace Hume Carothers
(Born
April 27, 1896: Died April 29, 1937)
American chemist who developed nylon
(1935), the first synthetic polymer fibre to be spun from a melt. He produced
this polyamide, by condensation of adipic acid and hexamethylenediamine. He worked
for the duPont chemical company as head of organic chemistry research from 1928.
Through his study of long-chain molecules, now called polymers, he also developed
the first successful synthetic rubber, neoprene (1931). He suffered from depression,
and died by suicide at the age of 41 before nylon had been commercially exploited.
DuPont produced nylon commercially from 1938 and laid the foundation of the synthetic-fibre
industry. Nylon proved outstanding in its properties as a synthetic analog of
silk.
April
28: J. Willard Gibbs
(Born February
11, 1839: Died April 28, 1903)
Josiah Willard Gibbs was a theoretical physicist
and chemist who was one of the greatest scientists in the U.S. in the 19th century.
His application of thermodynamic theory converted a large part of physical chemistry
from an empirical into a deductive science.
April
27: Rolf William Landauer
(Born
February 4, 1927: Died April 27, 1999)
German-born American physicist whose
discovery of what came to be known as Landauer's principle (that the erasing of
computer information causes a loss of energy) led to the development of more efficient
computers.
April
26: Intergrated Circuit
In 1961,
the integrated circuit was patented by Robert Noyce (No. 2,981,877).
April
25: Anders Celsius
(Born
November 27, 1701: Died April 25, 1744)
Swedish astronomer, physicist and
mathematician who is famous for the temperature scale he developed. Celsius was
born in Uppsala where he succeeded his father as professor of astronomy in 1730.
It was there also that he built Sweden's first observatory in 1741. He and his
assistant Olof Hiortner discovered that aurora borealis influence compass needles.
Celsius' fixed scale (often called centigrade scale) for measuring temperature
defines zero degrees as the temperature at which water freezes, and 100 degrees
as the temperature at which water boils. This scale, an inverted form of Celsius'
original design, was adopted as the standard and is still used in almost all scientific
work.
April
24: IBM-PC
In 1981, the first
IBM personal computer was introduced.
April
23: Battery
In 1940, a leak-proof
flashlight battery (Ray-o-Vac) was patented in the U.S. by Herman Anthony (No.
2,198,423).
April
22: Gaston Planté
(Born
April 22, 1834: Died May 21, 1889)
French physicist who produced the first
electric storage battery, or accumulator, in 1859; in improved form, his invention
is widely used in automobiles.
April
21: Samuel Slater
(Born
June 9, 1768: Died April 21, 1835)
English-American mechanical engineer who
founded the American cotton-textile industry. Before 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. as well as many others in the New England region.
April
20: Ferdinand Braum
(Born June
6, 1850: Died April 20, 1918)
German physicist who shared the Nobel Prize
for Physics in 1909 with Guglielmo Marconi for the development of wireless telegraphy.
Braun is also known as the developer of the cathode-ray oscilloscope. He demonstrated
the first oscilloscope (Braun tube) in 1897, after work on high-frequency alternating
currents. Cathode-ray tubes had previously been characterized by uncontrolled
rays; Braun succeeded in producing a narrow stream of electrons, guided by means
of alternating voltage, that could trace patterns on a fluorescent screen.
April
19: Zygmunt Florenty von Wroblewski
(Born October 28, 1845: Died April 19, 1888)
Polish physicist who liquefied
the "permanent gases" such as nitrogen and carbon monoxide in larger
quantities than previously accomplished by Cailletet, whose method he improved.
In 1883, he achieved the static liquefaction of oxygen and air. He was the first
to liquify hydrogen. Although he achieved it only in a transient fine mist, he
published (1885) remarkably accurate data: critical temperature 33 K, critical
pressure, 13.3 atm and boiling point, 23 K (modern values 33.3 K, 12.8 atm, 20.3
K). He may also have had a hint of strange electrical properties at very low temperatures,
but his research was cut short upon his accidental death.
April
18: Sir John Ambrose Fleming
(Born
November 29, 1849: Died April 18, 1945)
English
engineer who made numerous contributions to electronics, photometry, electric
measurements, and wireless telegraphy. In 1904, he discovered the one directional
current effect between a positively biassed electrode, which he called the anode,
and the heated filament in an evacuated glass tube; the electrons flowed from
filament to anode only. Fleming called the device a diode because it contained
two electrodes, the anode and the heated filament. He noted that when an alternating
current was applied, only the positive halves of the waves were passed - that
is, the wave was rectified (from a.c. to d.c.). It would also take a radio frequency
wave and produce d.c.corresponding to the on and off of the Morse code transmitted
signals.
April
17: Benjamin Franklin
Born January
17, 1706: Died April 17, 1790)
American printer and publisher, author, inventor
and scientist, and diplomat. He become widely known in European scientific circles
for his reports of electrical experiments and theories. He invented a stove, still
being manufactured, to give more warmth than open fireplaces; the lightning rod
and bifocal eyeglasses also were his ideas. Grasping the fact that by united effort
a community may have amenities which only the wealthy few can get for themselves,
he helped establish institutions people now take for granted: a fire company,
a library, an insurance company, an academy, and a hospital. In some cases these
foundations were the first of their kind in North America.
April
16: Ferdinand Gotthold Eisenstein
(Born April 16, 1823: Died October 11, 1852)
German mathematician whose work
on the theory of elliptic functions and on quadratic and cubic forms led to theorems
for quadratic and biquadratic residues, a reciprocity theorem for cubic residues,
cyclotomy, and quadratic partition of prime numbers.
April
15: Johannes Stark
(Born
April 15, 1874: Died June 21, 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.
April
14: ENIAC proposed to Army
In
1943, a proposal for an electronic computer was submitted to colleagues at the
U.S. Army's Ballistics Research Laboratory by John Grist Brainerd, director of
research at the University of Pennsylvania's Moore School, where the proposal
was written by John Mauchly. In May 1943, the Army contracted the Moore School
to build ENIAC, the first electronic computer. Although ENIAC was not finished
until after the war had ended, it nevertheless marked a major step forward in
computing.
April
13: Microscope
In 1625, the word
"microscope" was coined as a suggested term in a letter written by Johannes
Faber of Bamberg, Germany, to Federigo Cesi, Duke of Aquasparata and founder of
Italy's Accademia dei Lincei (Academy of the Lynx). This academy, possibly the
world's first scientific society took its name after the animal for its exceptional
vision.
April
12: Theory of Relativity
In 1923,
American scientists studying Einstein's Theory of Relativity found further evidence
in support of its correctness.
April
11: Hydrogen-cooled generator
In 1941, the first hydrogen-cooled electrical generator for outdoor installation
in the U.S. was put into operation. Built by the General Electric Company for
the city of Glendale, Cal., it was rated 20,000 kW and cost $391,669. It was mounted
on an open deck.* (The first GE-built, hydrogen-cooled indoor generator started
operation started on October 12, 1937). In modern hydrogen-cooled turbo-generators,
hydrogen is used as a coolant fluid. The stator core is direct cooled with hydrogen,
for example, at a pressure of 3-6 bar. The advantage of hydrogen is a high thermal
conductivity and lower friction than air-cooled generators, thus more efficient
operation, lower fuel consumption, highest output capacity, and lowest operating
cost.
April
10: Frank Stephen Baldwin
(Born
April 10, 1838: Died April 8, 1925)
Inventor best-known for his development
of the Monroe calculator.
April
9: Thomas Johann Seeback
(Born April 9, 1770: Died
December 10, 1831)
German
physicist who discovered (1821) that an electric current flows between different
conductive materials that are kept at different temperatures, known as the Seebeck
effect. It is the basis of the thermocouple and is considered the most accurate
measurement of temperature. It is also a key component of the semi-conductor,
the foundation of the modern computer business. Seebeck's work was the basis of
German physicist Georg Simon Ohm (1789-1854) discoveries in electricity and of
French physicist Jean Charles Athanase Peltier (1785-1845), whose Peltier effect
became well known as a way to use electricity to freeze water (air conditioning,
refrigeration).
April
8: Johann Salamo Christoph Schweigger
(Born
April 8, 1779: Died September 6, 1857)
German physicist who invented the
galvanometer (1820), a device to measure the strength of an electric current.
He developed the principle from Oersted's experiment (1819) which showed that
current in a wire will deflect a compass needle. Schweigger realized that suggested
a basic measuring instrument, since a stronger current would produce a larger
deflection, and he increased the effect by winding the wire many times in a coil
around the magnetic needle. He named this instrument a "galvanometer"
in honour of Luigi Galvani, the professor who gave Volta the idea for the first
battery. Seebeck (1770-1831) named the innovative coil, Schweigger's multiplier.
It became the basis of moving coil instruments and loudspeakers.
April
7: Erik Ivar Fredholm
(Born April
7, 1866: Died August 17, 1927)
Swedish mathematician who founded modern integral
equation theory.
April
6: Teflon
In 1938, Du Pont researcher
Roy J. Plunkett and his technician Jack Rebok accidentally discovered the chemical
compound polytetrafluoroethylene (PTFE) that was later marketed as Teflon. Plunkett
was researching chemical reactions of the gas perfluoroethylene in order to synthesize
new types of refrigerant gases. Rebok found an apparently defective cylinder of
this gas, since no pressure was found when the valve was opened, even though the
cyclinder weight was the same as full cylinders. Rebok suggested sawing it open
to investigate. Inside was a slippery white powder. Plunkett found it had unusual
properties, a wonderful solid lubricant in powdered form, was chemically inert
and had a very high melting point. He realized it was formed by an unexpected
polymerization.
April
5: Faraday Lecture
In 1881, Hermann von Helmholtz presented The Faraday Lecture before
the Fellows of the Chemical Society in London. His topic was The Modern Development
of Faraday's Conception of Electricity. Helmholtz recognized Faraday as being
the person who most advanced the general scientific method, saying "His principal
aim was to express in his new conceptions only facts, with the least possible
use of hypothetical substances and forces."
April
4: Zénobe-Théophile Gramme
(Born April 4, 1826: Died January 20, 1901)
French electrical engineer
and inventor (1869) of the Gramme dynamo, a continuous-current electrical generator
that gave principal impetus to the development of electric power. In 1870 he invented
a continuous-current dynamo with a ring armature (a ring of soft iron around which
were placed insulated copper coils). This produced much higher voltages than other
dynamos of the time and was the first high-voltage direct-current generator practical
for mass production and distribution. Driven by steam-engines, they were immediately
successful and were used for a variety of purposes, including factory lighting,
electroplating, and lighthouses. With these dynamos, the era of large-scale electrical
engineering began.
April
3:
First cell phone call
In
1973, the first portable phone call was placed by inventor Martin Cooper. The
phone was 10
inches in height, 3 inches deep and an inch-and-a-half wide
and weighed 30-oz. Since then, cell phones have shrunk to a mere palm-size weighing
4-oz, and are used by a billion people around the world. Cooper's first ''shoebox''
phone replaced a car phone of the time that weighed more than 30 pounds and cost
thousands of dollars. A car phone owner had to drill a hole in his car to install
the antenna and most of the phone sat in the trunk. A control unit with a handset
was placed inside the car.
April
2:
Walter Chrysler
(Born April 2, 1875: Died August 18, 1940)
Walter P(ercy) Chrysler was the industrialist, inventor and manufacturer who founded
the Chrysler Corporation (1925), and developed the six-cylinder engine.
April
1:
Francois-Marie Raoult
(Born May 10, 1830: Died April 1, 1901)
French chemist who formulated a law on solutions (called Raoult's law) that made
it possible to determine the molecular weights of dissolved substances.
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