20 Afialysis of Sea Water. 



When these analyses are compared, it will be found that the 

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

 nean, 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 pla- 

 tina crucible, mixed with a little chloride of ammonium, to pre- 

 vent as much as possible the decomposition of the earthly chlo- 

 rides, and the residue carefully ignited, in order to volatilize the 

 chloride of ammonium, where, however, a dissipation of hydro- 

 chloric acid had taken place. 



Sometimes I found faint traces of oxide of iron, when the con- 

 centrated water was mixed with sulphocyanuret of potassium, 

 particularly after boisterous weather ; I found the same in respect 

 to organic matter. The sea-water taken on a fair and calm day, 

 when very transparent, did not yield the shghtest indication of 

 extractive matter when evaporated and ignited. A small quan- 

 tity of free carbonic acid gas has been likewise found ; and also 

 extremely minute traces of chloride of ammonium were detected, 

 when about 5 pounds of sea-water were evaporated in a water- 

 bath to nearly half an ounce, which, mixed with caustic soda, 

 produced fumes close to a glass rod wetted with hydrochloric 

 acid. 



Sea-water has been likewise examined for silica, alumina, stron- 

 tia, manganese, phosphoric acid, and nitric acid, none of which 

 could be detected. 



The sea-water used for the occasion was taken on the 3d of 

 June, from the surface, six miles from the shore, at high water. 

 The weather was fair, the sea calm and extremely transparent. Its 

 specific weight was at 60° Fahr. 1 -0274. Another portion ob- 

 tained by a proper apparatus from the very bottom of the sea, 10 

 fathoms deep, was of the same specific gravity, and likewise that 

 taken almost close to the shore. In the month of July, after a 

 previous rainy day, the sea-water taken four miles from the shore, 

 had at 60° Fahr. a specific gravity of 1-0274 ; at a distance of 2 

 miles, 1-0271; and close to the shore, 1-0268. It was examined 

 several times in August, the weather being fair and warm, when 



