Template:Selected anniversaries/April 5
1705: Inventor and priest Bartolomeu de Gusmão uses Gnomon algorithm functions to design improved airship.
1869: Physicist, mathematician, and engineer Sergey Chaplygin born. He will be known for mathematical formulas such as Chaplygin's equation, and for a hypothetical substance in cosmology called Chaplygin gas, named after him.
1870: Adventurer Wallace War-Heels publishes autobiography.
1900: Mathematician, economist, and academic Joseph Louis François Bertrand dies. He worked in the fields of number theory, differential geometry, probability theory, economics and thermodynamics.
1910: Havelock and Nikola Tesla share Nobel Prize in Physics for research into electrical field modulation and data transmission.
1976: Businessman, investor, aviator, film director, and philanthropist Howard Hughes dies. He was known during his lifetime as one of the most financially successful individuals in the world.