manager of the _ergastulum_ felt that he knew us he let us go
unchained like the rest of his charges.

This was because of the structure of the _ergastulum_. It was located in
the cellars of one of the six or more granaries of Placentia, which has,
near each city gate, an extensive public store-house. The granary under
which we were immured was that near the Cremona gate. Above ground it was
a series of rectangles about courtyards each just big enough to
accommodate four carts, all unloading or loading at once. It was
everywhere of four stories of bin-rooms, all built of coarse hard-faced
rubble concrete. The cellars were very extensive, and not all on one
level, being cunningly planned to be everywhere about the same depth
underground. Where their floor-levels altered the two were joined by short
flights of three, four or five stone steps, under a vaulted doorway, in
the thick partition walls.

Each cellar-floor was about four yards below the ground level so that a
tall man, standing on a tall man's shoulders, could barely reach with his
outstretched fingers the tip of the sill of one of the low windows. These
windows, each about a yard high and two yards broad, were heavily barred
with gratings of round iron bars as thick as a man's wrist, set too close
together for a boy's head to pass between them, and each two bars hot-
welded at each intersection, so that each grating was practically one
piece of wrought iron, made before the granary was built and with the ends
of each bar set deep in the flinty old rubble concrete. The inmates need
not be chained, as no escape was possible through the windows, though raw
night air, rain, snow at times and the icy winter blasts came in on us
through them.

Similarly no escape was possible up the one entrance to the cellars, which
was through an inner courtyard, from which led down a stone stair with
four sets of heavy doors; one at the bottom, one at each end of a landing
lighted by a heavily barred window, and one at the top. Between the inner
and outer courtyard were two sets of heavier doors and two equally heavy
were at the street entrance of the outer courtyard. On the stair-landing
was the chained-up porter-accountant seated under the window on a backless
stool by a small, heavy accountant's table on which stood a tall
_clepsydra_ by his big account-book. Checking the hours by the
_clepsydra_, he entered the name of every human being passing, up or down
that stair, even th