Apparatus for Analyzing Calcareous Marl, 8fc. 299 



The attention of the French and German chemists having lately 

 been much directed to the constitution of the vegetable acids, various 

 improved methods of obtaining the malic acid in a pure form have 

 been densed and published. In all these however the acid is ex- 

 tracted either from the Sorbus or Sempervivum. As in the fornier of 

 these plants it exists almost entirely uncombined, while in the latter 

 it is united with lime as a malate, a separate process is necessary for 

 each. In procuring the acid from the Sempervivum the malate is 

 converted into a bi-malate by the addition of so much sulphuric acid 

 as will remove one half of the lime, and then other operations up- 

 on the crystallized bi-malate are necessary to separate the malic acid. 

 From the comparative ease with which the bi-malate may be obtained 

 from the berries of the Rhus, and the purity of the salt when pro- 

 cured in this way, there is no doubt that this fruit may be very ad- 

 vantageously employed in preparing malic acid for chemical purpo- 

 ses. I have as yet made no experiments to ascertain the amount of 

 bi-raalate which a given weight of the ripe berries of each of our 

 species of Rhus will furnish, but I have no doubt that it would be 

 found very considerable. Of the medicinal properties of the salt I 

 believe little or nothing is known. Should it have any value in this 

 respect, or should its pleasant acidity bring it into general favor as an 

 ingredient in our summer beverage, the great abundance of the plants 

 in which it exists would no doubt make it an object of extensive 

 manufacture. 



Art. XIII. — Apparatus for Anahjzhig Calcareous Marl and other 

 Carbonates; by William B. Rogers, Professor of Chemistry 

 and Natural Philosophy in William and Mary College. 



In consequence of the extensive use now made of the marls . of 

 of our tertiary strata in the agriculture of the state, I am frequently 

 called upon to analyze these substances with the view chiefly of de- 

 termining the proportion of carbonate of lime. In doing this by the 

 method generally employed, viz. disengaging the carbonic acid by 

 chemical action and then estimating the carbonate by the weight which 

 is lost, I have found the instnuiient of Rose so cumbrous and difficult 

 of management that I have abandoned it altogether, and am now in the 

 habit of using the little apparatus about to be described, which gives 

 with comparative facility far more accurate results. 



