March 11 marks the passing of Archibald Scott Couper. Couper was a Scottish chemist who discovered carbon atoms were tetravalent and could form long chain molecules.
The general theory of the arrangement of atoms in molecules held molecules were built off a single central atom. The problem with the theory was many organic compounds seemed to not have a central atom. Couper’s discovery of carbon chains was important to knock down this theory.
Couper wrote up his paper and passed it to his friend and fellow chemist, Charles Adolphe Wurtz to present at the French Academy of Sciences. Unfortunately for Couper, Wurtz procrastinated on presenting the paper to the Academy and Couper lost priority to a German chemist, August Kekulé who also discovered carbon could form multiple bonds and determined the ring structure of benzene. Couper did not take this loss well and never published a scientific paper for the rest of his life.
One lasting contribution Couper gave to chemistry was the way chemical structures are drawn. He was the first to draw structures where element symbols were connected by lines that represent the bonds between them.
Notable Science History Events for March 11
1955 – Alexander Fleming died.
Credit: US National Library of Medicine
Fleming was a Scottish biologist who discovered the antibiotic penicillin. Penicillin was the first of many antibiotic drugs that successfully treated a variety of bacterial diseases. This discovery would earn him part of the 1945 Nobel Prize in Medicine with Ernst Chain and Howard Florey. Fleming was also the first to identify the enzyme lysozyme and identified its antibacterial effects.
1950 – Arthur Jeffrey Dempster died.
Emilio Segrè Visual Archives
Dempster was a Canadian-American physicist who designed and built the first mass spectrometer. Mass spectrometers are used to separate a sample’s components by mass. He later used this device to discover the uranium isotope U-235, the main isotope used in atomic bombs.
1920 – Nicolaas Bloembergen was born.
Dutch National Archives
Bloembergen was a Dutch-American physicist who shares half the 1981 Nobel Prize in Physics with Arthur Schawlow for the development of laser spectroscopy. Kai Siegbahn’s research into the development of electron spectroscopy earned him the other half of the prize.
Bloembergen also greatly improved the design of masers or microwave lasers and made several contributions to microwave spectroscopy.
1892 – Archibald Scott Couper died.
1818 – Henri-Étienne Sainte-Claire Deville was born.
Deville was a French chemist who synthesized toluene and anhydrous nitric acid. He also developed the first economical process to produce aluminum.
He and Jules Henri Debray provided the purified platinum for the standard meter bar at the Metric Commision in Paris. This bar was the standard until 1960 when the meter was defined from the wavelength of krypton-86.
1811 – Urbain Le Verrier was born.
Verrier was a French mathematician who predicted the existence of Neptune based on the irregularities of the orbit of Uranus. His calculations were used to discover Neptune within 1° of his predicted position.
Verrier demonstrated some newly discovered comets were actually previously known comets with orbits altered by Jupiter’s gravity. He also proposed the existence of a planet Vulcan inside the orbit of Mercury to explain Mercury’s irregular orbit.