THE laws that govern the movements of sand along the sea-shores, the formation and corrosion of beaches, the shifting of bars and sand-banks at the mouth of rivers, and the silting up of harbours ...

As you have more than once permitted me to discuss the problem of sea-waves in your columns, I venture to point out that in your interesting article on Signer Cornaglia's work on sea beaches (p.

Schematic showing how a series of beach deposits would have formed at the Zhurong landing site in the distant past on Mars (left) and how long-term physical and chemical weathering on the planet ...