Published online by Cambridge University Press: 27 March 2009
1. The nature of the replaceable base in a clay or soil exerts a profound effect on the physical properties. Clay-like properties are exhibited most strongly in the case of lithium, sodium, and magnesium.
2. The proportion of fine material in a soil (i.e. that which remains in suspension in a column 10 cm. high after 14 days) cannot be correlated with other physical properties. Thus a soil of which over 50 per cent, was dispersed to this extent was the least plastic of those examined.
3. A comparison of sodium, potassium, and calcium clays and soil showed that potassium resembles sodium in its chemical relationships as indicated by base exchange, but is very different from it in such physical properties as plasticity and permeability.
4. Using mixtures of one-half normal chlorides of two bases, calcium and potassium are absorbed in equivalent amount while the sodium absorbed is only one-sixth of the amount of either of the other two.