CHAP. 63.—GRÆCANIC PAVEMENTS.
We must not omit here one other kind of pavement, that
known as the "Græcanic." The ground is well rammed down,
and a bed of rough work, or else broken pottery, is then laid
upon it. Upon the top of this, a layer of charcoal is placed,
well trodden down with a mixture of sand, lime, and ashes; care
being taken, by line and rule, to give it a uniform thickness
of half a foot. The surface then presents the ordinary appearance
of the ground; but if it is well rubbed with the
polishing-stone, it will have all the appearance of a black
pavement.
