Les Sept Boules de cristal
Calculus's introduction appears to have supplied Hergé with the bizarre nature he wished to portray in a man of science. Other figures of high education were shown as more stable and level-headed. The members of the archaeological expedition who fall victim to "The Seven Crystal Balls" show no apparent signs of eccentricity. The most prominent member of this group is Calculus's friend Hercules Tarragon, with whom he attended university. Tarragon is a large, ebullient man, possessing a jovial nature, but not necessarily eccentric.