OF SEA-WATER IN THE DIFFERENT PARTS OF THE OCEAN. 
213 
of soda or potash. In some sea-weeds it occurs in considerable quantity, particularly 
in the ashes of Zostera marina when it is in full growth. This ash contains about 
4 per cent, of it, enough, when muriatic acid is poured upon the ash, to cause an effer- 
vescence of chlorine. Manganese is found in a much smaller quantity in the animals of 
the sea. 
21. Aluminium. — I have often tried to find alumina in sea-water which had been 
filtered, but always without result, until at last, in my experiments to find boracic acid, 
I found alumina also, as is mentioned under boron. Aluminium must thus be enume- 
rated as one of the elements that occur in the water of the sea. It occurs in greater 
quantity than most metals, iron, and perhaps manganese, excepted. 
22. Magnesium. — This element occurs, as is well known, in large quantity in sea- 
water, in about the same quantity as sulphuric acid, and only sodium and chlorine are 
found in greater quantity. Sea-weeds contain it likewise in considerable quantity, and 
it is a constant companion of the carbonate of lime which the shell-fishes and corals 
deposit. In Serjgula jiligrana it amounts to 13-49 per cent, carbonate of magnesia. Its 
average quantity is, however, only 1 per cent. 
23. Calcium. — Lime occurs in sea-water in a small quantity combined with carbonic 
acid, and dissolved in an excess of it ; in a greater quantity combined with phosphoric 
acid, and as fluoride of calcium ; but the greatest quantity is combined with sulphuric 
acid. Among all the bases which river-water carries into the sea, lime is the most fre- 
quent ; and it is only owing to the organic beings of the sea, and principally to its lower 
animals, that so small a quantity remains, lime being constantly separated by the organo- 
chemical action of these animals. 
24. Strontium. — I have discovered this element in the sea-water, and also in the 
deposit of the boilers of the Transatlantic steamers. It occurs likewise in the ashes of 
the fucoid plants, and specially in the Fucus vesiculosus. I shall here explain how I 
have convinced myself that this plant contains both strontia and baryta. When the ash 
was successively extracted, first with water, and then with muriatic acid, a rather 
considerable quantity of insoluble substances remained, which was fused with carbonate 
of soda, and again extracted by water containing some pure soda to dissolve the silica, 
while the sulphuric acid from the sulphate of strontia and baryta had combined with 
the soda of the carbonate. To remove the lime from the remainder, I dissolved it in 
muriatic acid which contained a little sulphuric acid. What remained undissolved was 
again fused with carbonate of soda and extracted with water. The remaining car- 
bonates were now dissolved in muriatic acid, and afterwards precipitated by a solution 
of sulphate of lime. The mixed sulphates of strontia and baryta were separated by 
flaosilicic acid, and the salt of strontia dissolved in alcohol, which then burned with the 
beautiful red colour of strontia. 
25. Baryta occurs both hi sea-weeds and in sea-animals, but the ashes of sea-weeds 
contain more of it than the corals and shells. It can even be determined directly in sea- 
water, and in the deposits of the boilers of the Transatlantic steamers. 
2 g 2 
