The year 1835 in science and technology included many events, some of which are listed here.

Astronomy

• August 5 - First sighting of the return of Comet Halley by Father Dumouchel, director of the Collegio Romano at the Vatican. It was next seen by Friedrich Georg Wilhelm Struve on August 21 at the Dorpat observatory. John Herschel had been expected to find the comet first, as he was at the time in South Africa with his 20ft focal length reflector - then the largest telescope in the world. He finally observed it in October, and watched until it reached its perihelion November 16. It reappeared in January 1836, and Herschel was the last person to observe it in May.

Chemistry

• Vinyl chloride first produced by Justus von Liebig and his student Henri Victor Regnault

Mathematics

• Dirichlet proves Dirichlet's theorem about prime numbers in arithmetical progressions

Physics

• William Rowan Hamilton states Hamilton's canonical equations of motion
• Gaspard-Gustave Coriolis examines motion on a spinning surface deduces the Coriolis effect

Technology

• Samuel Colt invents the revolver
• Samuel Morse develops the Morse code

Awards

• Copley Medal: William Snow Harris
• Wollaston Medal: Gideon Mantell

Births

• March 12 - Simon Newcomb (d. 1909), mathematician and astronomer.
• March 14 - Giovanni Schiaparelli (d. 1910), Italian astronomer.
• March 24 - Jožef Stefan (d. 1893), physicist and mathematician.
• March 29 - Gustaf Zander (d. 1920), physician.

Deaths

• August 18 - Friedrich Strohmeyer (b. 1776), chemist.
• September 14 - John Brinkley (b. 1763), astronomer.