Many carillons, according to a C-compass, are missing the lowest C and E bells (equating to the second- and fourth-largest bells if they were included). The reason is often financial: by omitting these bells, the construction of a carillon can be reduced significantly, sometimes by 20 percent for large installations. Since the early 1900s, European installations will often reintroduce the E bell, and instead of adding the C bell, they will include a B bell (which is a major second below the C-compass bell).
