The cadence, or frequency per day, of a tidal wave is not the same in all the basins. During the time the Earth revolves on its axis one time, in almost all the basins, there are two tidal waves (semi-diurnal basins), while in just a few basins, there is only one (diurnal basins).

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2.4.1 Confrontation on the tides - introduction.
2.4.2 Two different descriptions of the tides.
2.4.3 The physical formula valid for the tides.
2.4.4 The ratio of the forces.
2.4.5 Number of the tide waves.
2.4.6 Unit of space of a tide wave.
2.4.7 When Earth, Moon and Sun are aligned.

Code proposition: [P0] neutral; [P1] classic theory; [P2] favouring the inductive approach; [P3] inductive approach.

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[P2] The subject of the tide cadence is of crucial importance. If you may have one wave per day basins, and, at the same time, two waves per day basins, then there is another reason that the tides cannot be due to the attraction, but to something else.

In the current theory.

[P2] In the current theory, the cause of the tide (attraction) and the effect (formation of the tide wave) take place more or less at the same time. No wonder then that the criterion to tell the cadence of the tide is the number of the waves reaching the coast.

[P1] If during one day, the tidal wave reaches the coast twice, one say that the tide cadence of that basin is semi-diurnal. That is the most common occurence.

In a few basin, only one tide wave per day reaches the coast. Then, one say that the cadence of that basin is diurnal.

[P3] The two sentences are incompatible if the cause supposed is gravity.

Declinations of the Moon and the Sun.

[P1] The cause of the cadences is attributed to the declination of the generating celestial bodies.

Indeed, in seas situated at higher latitudes, where the Moon declination is extreme, we may find diurnal tides.

Also in tropical seas.

[P3] Indeed, we may find diurnal tides also in the tropical regions (examples: China sea, Mexico gulf).

Of course, the higher the latitudes, the higher may be the effect of leads and lags of the spatioles. However, that is not the clinching point.

The declinations of the generating bodies (Moon, Sun) can only modify the times of the local tide generation. Getting them earlier, or later. Even up to a fusion of two tidal waves into one. It does not change its daily cadence of generation (diurnal; semi-diurnal).

Distinction between generation and tidal wave.

When you have to determine the cadence of a tidal basin, the number per day of a tidal wave transit, on a coast, is not a reliable datum.

It is the cadence of the tide generation which gives us the cadence of a basin, not the waves reaching the coast.

The force which brings about the tides could generate a tide, either with a cadence of one per day, or with a cadence of two. For the time being, I assume that it is because of local features. The attraction cannot do that.

The tide generation cadence is clear-cut.

At a given location, the tide generation is clear-cut; it has either a diurnal, or a semi-diurnal cadence. A possible exception is where the cadence changes with the season (a topic to settle).