260 On the Chemical Composition of Clay-slate. 



If we assume that all the lime found in 2 A is mixed with the 

 clay-slate as a carbonate of lime, and so determine the quantity 

 of carbonic acid by the amount of the lime ; then, by deducting 

 this from the loss sustained by heating in No. 1, and by after- 

 wards determining the water, we obtain the following as the re- 

 sult of the first analysis. 



100.00 



100.00 



100.00 



The analysis of the portion separable by acids 



97.25 



98.76 



100.71 



If we calculate the composition of the whole according to the 

 results of the analysis of the component portions, we obtain the 

 following as the amount of the chemical constituents. 



Silica, .... 

 Alumina, . . . 

 Oxide of Iron, 

 Magnesia, . . . 

 Lime, .... 

 Potash, .... 

 Water, .... 

 Oxide of Copper, 

 Carbonate of Lime, 

 Carbon and Loss, 



59.92 

 14.89 

 9.03 

 4.42 

 0.51 

 2.75 

 4.45 

 0.25 

 2.43 

 1.35 



62.59 

 16.88 

 8.42 

 2.26 

 0.24 

 3.31 

 4.03 

 0.13 

 1.22 

 0.92 



100.00 



100,00 



100,00 



