THE CALCARIMETER : 



A NEW INSTEUMENT EOE ESTIMATING THE QUANTITY 0¥ 

 CAEBONATE OF LIME PEESENT IN CALCAEEOUS SUB- 

 STANCES. 



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Among the most ready methods used for the purpose of 

 estimating the quantity of carbonate of lime contained in cal- 

 careous substances are Davy's pneumatic and Eogers's methods, 

 the one estimating it from the bulk of carbonic acid, 

 and the other by the weight of the carbonic acid af- 

 forded by the action of an acid. The principal objec- 

 tion to the former is the complication of the apparatus, 

 and for the latter it is necessary to be furnished with 

 a more than ordinary pair of balances^ and a set of 

 accurate weights; whereas the instrument about to be 

 described is free from both these objections, with the 

 additional advantage of affording more accurate re- 

 sults. 



It appeared at first that by taking a certain quantity 

 of the substance to be examined, and letting fall upon 

 it by degrees a solution of acid, the strength of which 

 we know, that it might be possible to estimate the 

 quantity of carbonate of lime in the same manner as 

 the carbonates of the fixed alkalies are estimated. But 

 for this to succeed it is necessary that the substance 

 should be finely pulverized, and free from any materials 

 soluble in the acid used; but as it is not common to be 

 furnished with these two conditions, another method 

 had to be adopted, the principle of which is to treat 

 the calcareous substance with an excess of acid, the 

 strength of which is known, and then to find out the 

 amount of this excess, thereby knowing the quantity^ 

 of acid taken up, from which we can easily calculate the 

 quantity of carbonate of lime present. In the application of 

 this principle it will be found that any thing like difficult 



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