1814.] On the Sea Water on the Coasts of France. 205 



3. Ammonia occasions a very copious precipitate; and if we acid 

 an excess of ammonia and filter, the filtered liquid, when mixed 

 with potash, lets fell a white precipitate. The precipitate obtained 

 by potash is entirely soluble in sulphuric acid. 



4. Muriate of barytes and acetate of lead occasion copious pre- 

 cipitates, which are insoluble in nitric acid. 



5. Though it be extremely probable that sea water contains a 

 little of the animal matter called by medical men bituminous matter, 

 yet neither the tincture of nutgalls nor chlorine produced any sen- 

 sible change when mixed with 122 cubic inches of this water. 



G. Bicarbonate of potash occasions no precipitate in sea wafer; 

 but if the mixture be boiled, a white powder is deposited, which 

 dissolves with effervescence in sulphuric acid. 



7. The colour of syrup of violets is not sensibly altered by sea 

 water. A great quantity of this water renders tincture of turnsol 

 red ; but it recovers its blue colour when the liquid is boiled. 



Sea water renders the syrup of buckthorn green. This change 

 may be ascribed to the action of the earthy salts upon this re- 

 agent. 



Although the nature of the salts contained in sea water may be 

 in some measure known from these preliminary experiments, we 

 thought it necessary to be particularly careful in determining the 

 quantities of saline matter by analysis. 



We introduced 1000 grammes (15444 grains) of each of the 

 specimens of sea water into a retort furnished with a bent tube 

 plunging into lime water. There was first disengaged the air of 

 the vessels, and a quantity of air which existed in the sea water. 

 Then there passed oft' carbonic acid gas; but not till the sea water 

 became boiling hot. Carbonate of lime was formed, which weighed 

 7*7 grains. This quantity of carbonate of lime shows us that the 

 sea water contained 3'5 grains of carbonic acid gas. 



A glass receiver was now applied to the retort, and the distillation 

 was continued till half a litre (30 # 5 cubic inches) of liquid came 

 over. The product obtained in this way from each specimen of sea 

 water was rendered muddy by nitrate of silver and acetate of lead. 

 It contained neither muriate of lime nor muriate of magnesia ; for 

 the smallest quantity of these salts has the property of giving a 

 green colour to the syrup of buckthorn, which was not the case 

 with this product. Hence it would appear that a portion of muriate 

 of soda is volatilized during the distillation. A depot is formed 

 during the cooling, which consists merely of the earthy carbonates, 

 uf which we shall speak below. 



Tin evaporation of the water was finished in a basin of silver, 

 and the residue was dried at the temperature of boiling water. The 

 quantities obtained were as follows : — 



Water of the English Channel SG gramme* 



Atlantic 3S 



Mediterranean 41 



