Before Calculus appeared in Red Rackham's Treasure, Hergé had featured other highly-educated but eccentric scholars and scientists, such as:
- Dr. Sophocles Sarcophagus of Cigars of the Pharaoh who showed signs of being clumsy and forgetful before going completely mad.
- The absent-minded professor who appeared in The Broken Ear and who forgot his glasses, wore his cleaning-lady's overcoat, held his cane upside-down as if it were an umbrella, mistook a parrot for a man and left his briefcase next to a lamp post. (In the original edition published in 1935 his name is given as Professor Euclide, after the Greek mathematician known as the Father of Geometry).
- Professor Hector Alembick in King Ottokar's Sceptre, who had a bad habit of throwing his cigarettes on the floor.
- Two astronomers from The Shooting Star also showed unusual and, in one case, mad behaviour: Philippulus the Prophet represented the dilemmas some face over religious belief and scientific research. In his case the conflict took a toll on his mind when the apocalypse appeared to be imminent. He then went around wearing bedsheets and beating a gong to warn of the event and later disrupted the eve of departure of the expedition sent to find a meteorite.
- His colleague, Decimus Phostle, though not mad, looked forward to the end of the world whose prediction he thought would make him famous. In contrast, he showed signs of maturity during the expedition when he called off the search for the meteorite in order to help a ship in distress.