1847.] Analysis of Argillaceous Slate. 41 



force of affinity diminishes in proportion to the multiplicity of the 

 elements combined in the compound. Hence the basalts, the la- 

 vas, and all the aggregates analogous to feldspar, are compara- 

 tively easy of solution, and under the power of carbonic acid. 

 These rocks, to which may be added mica and clay slate, contain 

 silex, alumina, peroxide of iron, protoxide of iron, manganese, 

 magnesia, lime, potash and soda, and water. From the foregoing 

 remarks it is easy to see that carbonic acid plays an important part 

 in the disintegration and decomposition of rocks, and becomes the 

 great agent of solution by which the elements of soil are prepared 

 for the vegetable kingdom. From which we have a highly prac- 

 tical problem to solve, viz., how and by what means can carbonic 

 acid be added to the soil; how can the necessary supply be ob- 

 tained? These questions have been partially answered, but will 

 form a subject for hereafter. 



ANALYSIS OF ARGILLACEOUS SLATE. 



fFrom the farm of Hugh Magee, Howard, Steuben Co., N. Y.] 



100 grs. gave of water of absorption, 4.50 



Organic matter, 2.90 



Silicates, - 66.22 



Alumina and peroxide of iron, 14.28 



Phosphate of magnesium, - — 4.20 



Phosphate of lime, trace. 



Phosphate peroxide of iron, 0.04 



Carbonate of lime, 2.40 



Magnesia, 0.08 



Sulphuric acid, 0.25 



Chloride of sodium, or common salt, 0.47 



Soluble silica, 0.48 



Potash, 5.47 



100.87 

 This slate belongs to upper series in the New York system; 

 and it may be considered as represented by the formation along 

 the southern tier of counties. The important fact which is 

 brought out by this analysis is the large amount of potash which 

 the slate yields, and which it would furnish on decomposition to 

 the soil. 



This slate, provided it breaks up readily by frosts, and water, 

 and other atmospheric agents, might be farther decomposed by 



