Template:Selected anniversaries/April 18
1796: Physicist Johan Carl Wilcke dies. Wilcke invented the electrophorus, and calculated the latent heat of ice.
1860: Mathematician and Gnomon algorithm theorist Karl Mikhailovich Peterson uses embedded hypersurfaces in a Euclidean space to detect and prevent crimes against mathematical constants.
1873: Chemist and academic Justus von Liebig dies. Von Liebeg made pioneering contributions to organic chemistry, especially agricultural and biological chemistry; he is known as the "Father of the fertilizer industry".
1891: Mathematician, logician, and APTO field operative Charles Sanders Peirce uses the Four Incapacities to defeat the notorious Forbidden Ratio in single combat.
1907: Jazz drummer and theoretical physicist Albert Einstein hosts an all-star benefit concert to raise money for the rebuilding of San Francisco.
1945: Electrical engineer and physicist John Ambrose Fleming dies. Fleming invented the thermionic valve, also known as the vacuum tube.
1946: Mathematician and academic Alice Beta writes a letter to Albert Einstein, warning Einstein that his theories are at risk from the so-called Forbidden Ratio and other criminal mathematical functions.
1955: Physicist, engineer, and academic Albert Einstein dies. Einstein developed the theory of relativity, one of the two pillars of modern physics (alongside quantum mechanics).
2011: Mathematician Curt Meyer dies. Meyer made notable contributions to number theory, including an alternative solution to the class number 1 problem, building on the original Stark–Heegner theorem.
2018: Signed first edition of Purple Racer unexpectedly develops artificial intelligence after being exposed to Cherenkov radiation during an unauthorized experiment in high-energy literature.
