t mounts and separates two Stones
falls directly upon the middle of the Stone which is below.

Some Authors call this sort of Masonry _Incertain_, but they are
mistaken; for they read _Incerta_ instead of_Inserta_; it is not so
Beautiful as the Net-work, but it is more solid and durable. See the
Figure BB. Table I.

The Masonry which _Vitruvius_ says is particular to the _Greeks_, is
that, where after we have laid two Stones, each of which make a Parement
or _Course_, another is laid at the end, which makes two Parements or
_Courses_, and all the Building through observe this Order. This may be
call'd _Double-Binding_; for the Binding is not only of Stones of the
same _Course_ one with another, but likewise of one _Course_ with
another _Course_. See Figure CC. Table I.

The manner of Walling by unequal Courses call'd _Isodomum_ by the
Ancients, differs in nothing from the Masonry call'd _Bound-Masonry_,
but only in this, that the Stones are not hewed. See Figure D. Table I.

The other manner by unequal Courses call'd _Pseudisodomum_ is also made
of unhewed Stone, and laid in _Bound-Work_, but they are not of the same
thickness, and there is no equality observ'd, but only in the several
Courses, the Courses themselves being unequal one to another. See Figure
A. Table I.

The Masonry which is fill'd up in the middle, call'd by the Ancients
_Emplecton_, is likewise made of unhewed Stone and by Courses, but the
Stones are only set in order as to the _Parements_ or _Courses_, but the
middle is fill'd up with Stones thrown in carelesly among the Mortar.
See Fig. FF, GG, H. Table I.

Among all these sorts of Masonry, that will always be best which is made
of Stones of an indifferent size, rather lesser than greater; to the end
that the Mortar penetrating them in more parts may bind them faster, and
the strength of the Mortar does not so soon decay. For we see that the
Mortar which is laid in the Joints or Seams of the greater Stones with
time decays and turns to Dust, which never happens to the most Ancient
Fabricks which have been built of little Stones. From thence we may
conclude, that it is ill Husbandry to be sparing of Mortar.

For this reason _Vitruvius_ proposes another sort of Masonry, which may
be call'd the _Compound Masonry_, for it is all the former together, of
Stones hewed and unhewed, and fastned together with Cramp-Irons. The
Structure is as follows: The _Courses_ being made of hew'd Stone, the
middle