the Censor disapproves of lime prepared from stones
of various colours: that made of white stone is the best.
Lime prepared from hard stone is the best for building purposes, and that from porous stone for coats of plaster. For
both these purposes, lime made from silex is equally rejected.
Stone that has been extracted from quarries furnishes a better
lime than that collected from the beds of rivers; but the best of
all is the lime that is obtained from the molar-stone,2
of a more unctuous nature than the others. It is something
truly marvellous, that quick-lime, after the stone has been subjected
to fire, should ignite on the application of water!