AbstractsLaw & Legal Studies

"A clay's essential character is its plasticity, whether it is to be used for common brick purposes, the manufacture of refractory articles, or merely as a bonding agent for nonplastic materials. Plasticity is a very large subject; there are many theories as to its cause and many methods have been developed to record it, but so far no satisfactory quantitative measure of plasticity has been found. Perhaps the most satisfactory method is to judge by handling the clay, and with constant practice one can become expert in judging the plasticity of a clay by its feel. Such a method is, however, unscientific and any possible difference in opinion has to be considered. We know that gradual addition of water to a clay brings about an increase in plasticity until what is known as the soft mud stage or maximum plasticity stage is reached, after which continued increase in water addition brings about the sticky stage" – Introduction, p. 1-2.