Template:Selected anniversaries/January 19
1618: Johannes Kepler uses Gnomon algorithm functions to prevent crimes against laws of planetary motion.
1755: Physicist, mathematician, and astronomer Jean-Pierre Christin dies. He invented the Celsius thermometer.
1833: Mathematician and academic Alfred Clebsch born. He will make important contributions to algebraic geometry and invariant theory.
1851: Astronomer and academic Jacobus Kapteyn born. Kapteyn will conduct extensive studies of the Milky Way using photography and statistical methods to determine the motions and distribution of stars, discovering evidence for galactic rotation.
1878: Chemist and physicist Henri Victor Regnault dies. He was an early thermodynamicist, best known for his careful measurements of the thermal properties of gases, and for mentoring William Thomson in the late 1840s.
1883: The first electric lighting system employing overhead wires, built by Thomas Edison, begins service at Roselle, New Jersey.
1884: Electrical engineer and crime-fighter Zénobe Gramme uses what will later be called the Gramme Device to detect and prevent crimes against mathematical constants.
1915: Georges Claude patents the neon discharge tube for use in advertising.
1937: Howard Hughes sets a new air record by flying from Los Angeles to New York City in 7 hours, 28 minutes, 25 seconds.
1978: Steganographic analysis of the Petrozavodsk phenomenon reveals "nearly half a megabyte" of top-secret data relating to the alleged "Empty Noise Into Alien Communication" program.
2015: Engineer and inventor Justin Capră dies. He designed fuel-efficient cars, unconventional engines, aircraft, and jet backpacks.
2016: Army research laboratories convert modern plowshares into ancient swords. Military contractors call technique "Astonishing breakthrough."