H. Wurtz Contributions to Analytical Chemistry. 189 
acid is added, the liquid becomes almost solid. With chlorid of 
strontium the precipitate is more slowly obtained. In each case, 
the precipitate, after being rinsed two or three times with pure 
nitric acid and dried upon porous earthenware, was entirely com- 
posed of nitrate without any chlorid. A solution of corrosive 
sublimate gave also by the same treatment a large crystalline 
precipitate, which appeared, however, to be chlorid and not 
nitrate of mercury. 
he chlorids of potassium and sodium did not give immediate 
precipitates, but on standing for a few hours in the cold, crops 
of large crystals were obtained, which were easily recognized as 
ni 5 T e liquid poured off from these crystals gave, on 
addition of alcohol, further crystalline precipitates of nitrates of 
x re agen must remain in solution in the excess of nitric acid. 
itrie acid which has been employed for such precipitations is for 
many uses as as before, and may purified by simple dis- 
tillation, or concentrated by evaporation and used again for the 
Same purpose. : 
It = unnecessary to do more than allude to the importance of 
our being able to obtain compounds of these metals perfectly 
pure—in the determination of their equivalent weights, for in- 
= The chlorids of barium and strontium are precipitated by mu- 
Tiatic acid, as well as by nitric; so that when pure chlorids are 
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