Sep 23, 1624: Galileo sent one of his compound microscopes, along with a letter, to a leading scientist of the day, his friend Federico Cesi in Rome. Galileo wrote some tips on how to use the microscope. Galileo did not invent the microscope, but made improvements to it. Galileo also wrote of his own observations, “I have contemplated a great many animals with infinite admiration”. Cesi worked with Francesco Stelluti and viewed the anatomic structure of bees, described in their text, Apiarium (1625), the first publication on microscopic discoveries.
Sep 23, 1791: Johann Franz Encke, German astronomer, was born. In 1819 he established the period of the comet now known by as Encke’s Comet. At at 3.3 years it has the shortest period of any known comet.
Sep 23, 1819: French physicist, Armand-Hippolyte-Louis Fizeau, was born. In 1849, he was the first to measure the speed of light successfully without using astronomical calculations. Fizeau sent a narrow beam of light between gear teeth on the edge of a rotating wheel. The beam then traveled to a mirror five miles (8 km) away and returned to the wheel. If the wheel was spinning at the right speed, and fast enough, a tooth would block the returning light. Knowing the rotational speed and the mirror’s distance, Fizeau directly measured the speed of light. He also found that light travels faster in air than in water, which confirmed the wave theory of light, and that the motion of a star affects the position of the lines in its spectrum. With Jean Foucault, in 1847, he proved the wave nature of the Sun’s heat rays by showing their interference (1847).
Sep 23, 1846: The German astronomer Johann G. Galle discovered Neptune after only an hour of searching, within one degree of the position that had been computed by Urbain-Jean-Joseph Le Verrier. Independently of the English astronomer John C. Adams, Le Verrier had calculated the size and position of a previously unknown planet, which he assumed influenced the irregular orbit of Uranus, and he asked Galle to look for it.
Sep 23, 1861: German engineer and industrialist, Robert Bosch, was born. He invented the spark plug and the magneto for automobiles. His firm produced a wide range of precision machines and electrical equipment throughout the world.
Sep 23, 1869: Mary Mallon (Typhoid Mary) was born. She was the quarantined disease carrier known as Typhoid Mary, the famous typhoid carrier in the New York City area in the early 20th century. Fifty-one original cases of typhoid and three deaths were directly attributed to her. Countless more were indirectly attributed. She herself was immune to the typhoid bacillus (Salmonella typhi).
The outbreak of typhus in Oyster Bay, Long Island, in 1904 puzzled the scientists of the time because they thought they had wiped out the deadly disease. Mallon’s case showed that a person could be a carrier without showing any outward signs of being sick. This led to most of the health code laws on the books today. She died not from typhoid but from the effects of a paralytic stroke.
Sep 23, 1879: Richard S. Rhodes invented the Audiophone, the first hearing aid.
Sep 23, 1915: American physicist Clifford G. Shull was born. Shull shared the 1994 Nobel Prize for Physics with Canadian physicist Bertram N. Brockhouse. Shull’s part of the award was for his development of neutron-scattering techniques, especially the neutron diffraction process that gave scientists a new tool to investigate the atomic structure of matter.
Sep 23, 1930: Johann Ostermeyer of Athegnenber, Germany, patented his “Improvements in flash lights used for photographic purposes.” The modern photographic safety flash bulb evolved from this design, which used aluminium wire or foil in oxygen. Unfortunately, all too frequently, these versions exploded. The flashbulb was introduced to the American market in 1930 by General Electric. Flash cubes appeared in 1966, and the percussively ignitable “Magicube” in 1970.
Sep 23, 1949: President Truman shocked America with a terse announcement, “We have evidence that within recent weeks an atomic explosion occurred in the USSR.” The alarm stimulated activity in scientific and political circles. An arms race was the clear response. On Jan 31, 1950, President Harry S. Truman announced a program to develop the hydrogen bomb. He said, “I have directed … work on all forms of atomic weapons, including the so-called hydrogen or superbomb. Like all other work in the field of atomic weapons, it is … consistent with the overall objectives of our program for peace and security … until a satisfactory plan for international control of atomic energy is achieved.”
Sep 23, 1953: WD-40 was invented and recorded for the first time in the Rocket Chemical Company’s logbook. The aerospace company, located in San Diego, California Southern California was trying to develop a lubricant that penetrated and displaced water. The 40th formulation was successful. It was created by Norm Larsen. In 1958, it was packaged in cans and sold to consumers in San Diego, California as WD-40, its original test designation.
Larsen founded the company in 1953 with the intent to supply materials used in the manufacture of nuclear missiles. WD-40 was originally intended to coat structural components and prevent corrosion by displacing water. WD-40 was widely successful, but it was the company’s only product. So, the company’s name was changed in 1969 to the WD-40 Company.
Sep 23, 1999: the Mars Climate Observer apparently burned up as it was about to go into orbit around the Mars.