Professor Cuthbert Calculus (French: Professeur Tryphon Tournesol) is a good friend of Tintin, and one of the main characters in the series. He has invented many things, including the rocket in Destination Moon, the shark proof submarine in Red Rackham's Treasure, and many more inventions like the clothes-press, the Super Calcacolor, motorized skates, etc. He is very nearly deaf though he claims he is just a little hard of hearing in his right ear.
It was he who generously supplied the large sum when Captain Haddock bought Marlinspike Hall. The Captain therefore allows him to live there. He is usually carrying his pendulum which he uses to find direction and navigate through the many problems he encounters. He also dislikes it when somebody tells him that he is acting the goat, and gets extremely angry if he is called a goat. In Flight 714, Calculus becomes infuriated when Carreidas pops his hat up, and releases completely raw fury and attacks him, showing unusual strength for his age.
Calculus first appeared in Red Rackham's Treasure, and was the result of Hergé's long quest to find the archetypal mad scientist or absent-minded professor. Although Hergé had included characters with similar traits in earlier stories, Calculus developed into a much more complex figure as the series progressed.