\paperw4260 \margr0\margl0 \plain \pard\tx150\tx870\tx1590\tx2310\tx3030\tx3750\tx4470\tx5190\tx5910\tx6630\ATXts240\qj\ATXbrdr0 \f1 \fs24 In Latium, they used, since t
he times of the Romans, a special volcanic rock which is loose and inconsistent called "pozzolana." This rock is very good to produce maltha, which has a special property to stick under water. It comes almost always from the Latium volcano in the current