PROPERTIES AND CONSTITUTION OF SEA-WATER. 531 



matters in suspension, and the green ones are slightly charged with 

 such substances. The solid particles held in the water constitute a 

 multitude of infinitely little mirrors, from the outside of which is re- 

 flected the light that penetrates the mass of the liquid. The rays 

 which are sent out, after having traversed only a thin stratum of wa- 

 ter, preserve their yellow parts. If the reflections are attenuated, the 

 water appears green ; and if, on account of the absence of solid mat- 

 ter, they do not exist at all, the sea is of a deep blue. In an indigo 

 sea, the crests of the waves will appear green on account of their lack 

 of thickness. The same rules are applicable to fresh water ; for the 

 salt is almost without effect on the color of sea-water — not quite with- 

 out effect, for, according to M. Spring, the clayey particles which 

 make the waves yellow are precipitated with a rapidity proportioned 

 to the salinity of the sea. These general laws are liable to be disturbed 

 by numerous accidental circumstances or local causes. The presence 

 of sea-weed, or of microscopic animalcules, may have great influence 

 on the color of the water. In tolerably shallow basins, the color of 

 the bottom has its effect. 



Several seas or gulfs have been given names alluding to their 

 colors. Some of these terms can be explained Avithout difficulty, but 

 others are not so easy to comprehend. The White Sea is so called 

 on account of its ice, the Black Sea from its storms, and the Yellow 

 Sea from the muddy waters poured into it by the Chinese rivers. The 

 waves of the Vermilion Sea, near California, are colored by the Rio 

 Colorado, which itself has a characteristic name. The water that 

 washes the European coasts has no perceptible odor ; or, if in single 

 cases it may be odorous, the smell is due to mud, or to decomposing 

 organic matters contained it it. Drinking-water, which is stored for 

 some time may also acquire a smell which it had not at first, through 

 the decay of the impurities in it. The cork of bottles containing 

 salt-water is sometimes eaten by sulphuretted hydrogen formed in 

 the water. 



Sea- water owes its characteristic taste to the chloride of sodium 

 held in solution, and to the bitter salts of magnesia which it contains. 

 Sometimes organic remains or weak proportions of fatty matters be- 

 come mixed with the superficial strata, so as to make them more nau- 

 seous than the same water drawn from greater depths. The pleasant 

 taste of the water inclosed in oyster-shells is due to the savory animal 

 juices that are dissolved in it. Mussels, which live and are fished 

 near the shore, sometimes absorb impurities from the drift-matter 

 around them, from which they develop the poisonous alkaloids called 

 ptomaines y hence they are unhealthy at some seasons. 



By a scientific prejudice that ruled for a considerable time, the bit- 

 ter taste of sea-water was believed to be caused by traces of bitumen. 

 The chemists who made analyses consoled themselves for not finding a 

 sign of that substance, the existence of which they suspected, by sup- 



