58 Dr. G. Schweitzer's Analysis of Sea-water as it exists 



quantity of chloride of ammonium. After the separation of 

 lime, magnesia was precipitated by the addition of ammonia 

 and phosphate of ammonia. 



The precipitate was washed with water containing 10 per 

 cent, of ammonia, whereby the solution of the precipitate was 

 prevented. After the sea-water had been freed from the 

 earthy chlorides and sulphates by hydrate of barytes and 

 carbonate of ammonia, it was evaporated to dryness, and the 

 residue heated to redness, and weighed. The alkaline chlo- 

 rides were dissolved in water mixed with perchloride of pla- 

 tinum, and evaporated to dryness. The residue digested 

 with spirits of wine containing 60 per cent, alcohol, left potassio 

 chloride of platinum, which was dried, weighed, and com- 

 puted as chloride of potassium. The surplus of the total 

 amount of the alkaline chlorides will give the precise quantity 

 of the chloride of sodium. 



The equivalent numbers have been computed according to 

 the Tables which H. Rose has affixed to his Handbuch der 

 analylischen Chemie. Zweiter Band. 



I subjoin by way of comparison an analysis of the Mediter- 

 ranean by Laurens. {^Journal de Pharmacie, xxi. 93.) 



Sea- water of the British Cliannel. Of the Mediterranean. 



Grains. Grains. 



Water 964<-74S72 959*26 



Chloride of sodium . . . 27-0594'8 27-22 



of potassium. . 0*76552 0*01 



of magnesium . .S*66658 6*14' 



Bromide of magnesium . 0*02929 — 



Sulphate of magnesia . . 2*29578 7*02 



of lime .... 1*40662 0*15 



Carbonate of lime . . . . 0*03301 /^^'''""'^^'""T 0*20 



1 & magnesia. J 



1000*00000 1000*00 



When these analyses are compared, it will be found that 

 the Channel water contains 9 times as much lime as the Me- 

 diterranean, but this can be accounted for, as the water flows 

 over a bed of chalk. The Mediterranean again has twice as 

 much magnesia and sulphuric acid. 



We also find that the English Channel contains in 1000 

 grains water, 35*25628 grains of anhydrous ingredients; 

 which amount corresponds very nearly to 35 grains, or 35*1 

 grains, obtained from several experiments, when 1000 grains 

 were evaporated in a platina crucible, mixed with a little 

 chloride of ammonium, to prevent as nmch as possible the 

 decomposition of the earthy chlorides, and the residue care- 



