294 MESSRS. THORPE AND MORTON ON THE 



phuric acid; the magnesia^ together with the excess of 

 the barium salt, was removed by boiling the solution with 

 milk of lime in a silver dish. The water was then filtered, 

 and the lime in solution precipitated by ammonium car- 

 bonate, and oxalate. On again filtering, adding a small 

 quantity of hydrochloric acid, and evaporating to complete 

 dryness, a minute amount of silica was rendered insoluble, 

 together with the traces of magnesia which had escaped 

 previous separation. This process was repeated until the 

 chloride dissolved to a perfectly clear solution. The dried 

 mass was then heated to dull redness, until it ceased to 

 lose weight. 





Mixed chlorides 



Amount in 



Water taken. 



obtained. 



1000 grams. 



57-1062 



1-3875 



27-15000 



57-1440 



i'392o 



27-21725 



Mean 27-18363 



In the foregoing process no account has been taken of 

 the minute quantity of lithia present in sea-water, the 

 whole of which would probably be contained in the mixed 

 chlorides — partly in the state of chloride, partly in that of 

 oxide. Although the presence of this substance in sea- 

 water may easily be demonstrated by means of the spec- 

 troscope, a few decigrams of the solid residue amply 

 sufficing for its detection, its quantitative determination 

 has hitherto not been attempted, more probably on ac- 

 count of the imperfect nature of the methods employed 

 in its separation than of the rej^atively minute quantity 

 contained in the water. Indeed it is almost certain 

 that the proportion of this element exceeds that of the 

 ammonia or nitric acid, silica, or oxide of iron, the amounts 

 of which substances in sea-water may be ascertained with 

 some degree of precision. 



