4 - The distance between the crests of waves.

===================================================

The distance between the crests of a long series of density waves does not change. That is not the case with the normal waves.

Volumes and wavelength of the normal waves.

The volumes of two successive waves, due to the passage of a boat, before hitting an obstacle, are different; also their wavelength, between two successive crests.

In density waves.

The same can’t be said of the density waves, which may show a remarkable regularity; even in a long series.

Lusenzo, 2007-04-28 u0750: spatiole B u0848; moon declination N 2°04; Moon distance km 404393ca; Eq t -2'25"; moon angular velocity 104.74 deltins/hr; variation -0.06 sec/hr. Water level: cm +20.