32 
of the Rio Colorado. It is difficult to say why the Arabian Gulf 
should be called the Red Sea, unless it be that it contains a good 
deal of a microscopic alga (called Trychodesmum erythreum) of a 
reddish colour. 
The chemical composition of sea water is extremely complex, 
owing to the numerous and ill understood combinations and double 
decompositions which occur among its various bases and acids. 
Analysis shows it to consist of certain simple substances, such as 
Chlorine, Bromine and Iodine, and four principal bases, soda, 
magnesia, lime, and potass combined with sulphuric acid. Chlorine 
is by far the most abundant principal in sea water, no less than 
half the weight of its saline matter being due to its presence. 
Soda is the next in quantity, then follow magnesia combined with 
sulphuric acid, and two substances much more rare, lime and potass. 
Sea water necessarily contains traces, more or less abundant, of every 
soluable substance in the world, including gold and silver. It was 
only in the last century that the silver fcund to exist in sea water 
was ascribed to the wrecks of the numberless vessels containing 
specie, especially to the rich Spanish galleons which had sunk with 
their cargoes of doubloons! The copper sheathing of ships often 
becomes slightly coated with an amalgam of silver, which, owing 
to galvanic action, rapidly deteriorates its quality. Small as is the 
quantity of silver in a gallon of sea water, it is nevertheless cal- 
culated by a trench chemist, that the ocean contains more silver 
in solution than there is in circulation among all the nations of the 
earth. In fact no less a quantity than two millions of tons. So 
enormous is the bulk of the ocean, that if all the salt it contains 
could be extracted and spread over the surface of the earth, it 
would form a layer of 80 feet in depth.—1000 grains of sea water 
contain :— 
Water... ssc; sec ce cen, con ne, | 0; one 
Chloride of Sodium .. .. 
Chloride of Magnesium ... 
Chloride of Potassium ° 
Bromide of Magnesia... .. .«. 
Sulphate of Magnesia 
Sulphate of Lime .. .. 
Carbonate of Lime .. 2... see see nee oe 
Leaving a residuum of ... wwe aM ee 
consisting of sulphuretted hydrogen, hydrochlorate of ammonia, 
iodine, oxide of iron, copper, and silver. 
Our seas thus contain the most powerful mineral waters which 
exist, and if sea water were only expensive, or limited in quantity, 
it would be credited with the cure of all the ills which flesh is heir 
to. Thousands of invalids would rush to any inland town posses- 
sing a spring half as rich in mineral matter as the sea, and yet it 
is hardly ever taken as a medicine, except by sailors, who know its 
value. In large doses sea water acts as an emetic; the concentra- 
= 
eascoan SE 
CHOY eRHO 
