hiteUigence and Miscellaneous Articles. 157 



\)j researches on ancient vegetables. The ashes of coal were ex- 

 amined, and the authors state that the presence of silver in them 

 was not so satisfactorily demonstrated as in the ashes of modern 

 vegetables. 



After many useless attempts, the authors gave up the direct 

 search for lead and copper in sea-water ; but they feel convinced 

 that it is to be found. By examining several species of fucus, they 

 found in their ashes Y^m °^ ^^^^ ^""^ ^ little copper : this proves 

 that if the quantity of these two metals in sea-water is so minute as 

 to escape detection by reagents, it is not sufficiently so to escape the 

 assimilating power of plants. 



To recapitulate the principal facts to which the authors call the 

 attention of the Academy ; they are the presence of silver in sea- 

 water, in sal-gem, and in organized beings ; the presence of lead 

 and copper in certain species of fucus, and consequently in the me- 

 dium in which these plants live. — Comptes Rendus, Decembre 26, 

 1849. 



OBSERVATIONS ON THE ESTIMATION OF LIME. j^ 



BY M. ALVARO REYNOSO. X 



Lime is one of the substances which chemists have occasion 

 most frequently to estimate the quantity of; and as this is always 

 effected in the state of oxalate of lime, it is important to know all the 

 properties of this salt, in order to avoid the errors which analysis 

 would otherwise occasion. 



With this view the author has undertaken some experiments on 

 the action of soluble salts, capable of becoming insoluble oxalates by 

 reacting on oxalate of lime. 



Oxalate of lime is converted by the influence of a soluble salt of 

 copper, as the chloride, sulphate and nitrate, into oxalate of copper. 

 The presence of lime has been ascertained in the liquor separated 

 from the oxalate of copper formed. The precipitate formed by mix- 

 ing one equivalent of chloride of calcium with one equivalent of 

 oxalate of ammonia dissolves in chloride of copper when poured into 

 it at once ; but by long standing, agitation, or boiling the liquor, a 

 precipitate is formed, which is shown by analysis to be oxalate of 

 copper ; when the chloride of copper is gradually added, the oxalate 

 of lime is converted into oxalate of copper, and there is at the same 

 time formed a soluble salt of lime : the oxalate of copper precipitates, 

 and is no longer redissolved by an excess of chloride of copper. 



The fact of the solution of oxalate of lime in chloride of copper, 

 and the subsequent precipitation of oxalate of copper, seems to be 

 analogous to what happens if phosphate of ammonia and magnesia is 

 prepared when a large quantity of hydrochlorate of ammonia is pre- 

 sent. This property does not belong exclusively to chloride of cop- 

 per ; since other salts, as chloride of calcium, hydrochlorate of am- 

 monia and chloride of sodium, equally retard the precipitation of the 

 oxide of copper. 



Oxalate of lime, when a large quantity of some salts is present. 



