noon
A light network of marine plants , of that inexhaustible family of seaweeds of which more than two thousand kinds are known , grew on the surface of the water . I noticed that the green plants kept nearer the top of the sea , whilst the red were at a greater depth , leaving to the black or brown the care of forming gardens and parterres in the remote beds of the ocean . We had quitted the Nautilus about an hour and a half . It was near noon ; I knew by the perpendicularity of the sun 's rays , which were no longer refracted . The magical colours disappeared by degrees , and the shades of emerald and sapphire were effaced . We walked with a regular step , which rang upon the ground with astonishing intensity ; the slightest noise was transmitted with a quickness to which the ear is unaccustomed on the earth ; indeed , water is a better conductor of sound than air , in the ratio of four to one . At this period the earth sloped downwards ; the light took a uniform tint .