Cambridge Chimes
The Westminster Quarters is the most common name for a clock chime melody used by a set of four bells to chime on each quarter-hour. The number of chime sets matches the number of quarter hours that have passed. It is also known as the Westminster Chimes, or the Cambridge Quarters from its place of origin, the church of St Mary the Great, Cambridge.
The melody consists of four different permutations of four pitches in the key of E major plus one arrangement omitting B3 and repeating E4 (3). The pitches are B3, E4, F♯4 and G♯4.
The notes used are:
played as three crotchets (quarter note) and a minim (half note). These are always played in the order 1, 2, 3, 4, 5, and each set is used twice every hour. Set 1 is played at the first quarter, sets 2 and 3 at the half, sets 4, 5 and 1 at the third quarter, and sets 2, 3, 4 and 5 at the hour, as follows:
The full hour chime is followed by one strike for the number of the hour by Big Ben (E3) (one strike for one o'clock, two strikes for two o'clock, etc.).
In other words, the cycle of five, 1, 2, 3, 4, 5, is played twice in the course of an hour. For a clock chiming mechanism, this has the advantage that the mechanism that trips the hammers need only store five sequences (1, 2, 3, 4, 5) instead of ten. The mechanism then plays two complete sets of five sequences for each complete hour. In musical terms, the first and third quarters finish on the dominant (B), whilst the second and fourth quarters (the half and full hours) finish on the tonic (E). This produces the very satisfying musical effect that has contributed so much to the popularity of the chimes. Note that the pitch of the Big Ben clip is closer to F than E in modern concert pitch.
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