REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1903 119 



3 Gypsum decomposes the double silicates of the earth, setting 

 free potash as a double sulfate. This action according to Storer 

 is as follows : 



Al,03^ 



Al,03 ^ 





CaO 



CaO 



I X Si02+CaOS03= 



CaO 



> X SiO.+K^O SO 



H^O ^ 



H2O , 





In this way potash is furnished in solution to the roots of the 

 plants, but a similar result should follow the application of 

 quicklime, with the difference that potash would be set free as 

 K2O, which would unite with carbon dioxid, which is present in 

 all natural water, forming the carbonate, instead of sulfate. 



In considering the mechanical effect of lime salts on the sioil, 

 it is to be noticed that the action on sandy or gravelly soils is 

 entirely distinct from the action on tough clay soils, but in each 

 case the soil is made more granular. 



The lime undoubtedly has no material effect in either case till 

 it is in solution, and it seems probable that the effect on the clay 

 soil is due almost entirely to the chemical action of the salts of 

 lime on the potash occurring in the clay. The action of lime on 

 loose sandy soils has been illustrated by placing lime in a muddy 

 liquid, whereby the mud flocculates and falls to the bottom. This, 

 however, does not seem to be a satisfactory explanation of the 

 action of the lime on the soil, inasmuch as, when such floccula- 

 tion takes place as is seen when lime is put into muddy water, it 

 is largely due to the fact that alum compounds have a tendency 

 to precipitate both solid and dissolved materials in any liquid 

 in which they may be found. This reaction is probably due to the 

 chemical change noted above, by which the lime is rendered 

 insoluble and the potash set free. In this case the particles of the 

 new compound of lime are likely to be more compact than the clay 

 or the solution of lime, so that they more readily fall to the 

 bottom. The flocculation observed in sandy soils is due largely 

 to the action of the lime on the clay which is almost invariably 

 found in these soils. 



