s first visible in the
distance, fully two miles away, a dozen or more horsemen, manifestly, even
at that distance, of military bearing: I caught, against the sunrays, a
gleam of crimson and a glint of gold; I conjectured a detail of Praetorian
Guards coming to arrest me or to put me out of the way.

Agathemer opened the upper door of the secret stair, which unlike most
doors, could be locked on either side, for my uncle always wanted to lock
the doors he used, whichever way he passed through them. After we had
passed this door Agathemer closed it behind us, and, as we stood in the
pitch dark, locked it.

We groped our way down the dizzying turns of the steep stair, Agathemer
going first and, at the bottom, whacking his knee-cap on the lower door.
This he unlocked and I found myself in a dim-lit cellar which I had
visited but twice before. Agathemer locked the stair-door behind us.

Now the minor tower, in which was the spiral stair, was built as a vent to
carry up into the air, far above the roofs of the villa, any miasma,
effluvium or exhalation from the drainage-water of the villa's baths,
kitchen and latrines. On the subject of harmful vapours from drains my
uncle was fanatical and to bear out his contentions he quoted from the
works of many celebrated philosophers and physicians, including those of
Galen.

Pursuant with his notions as to how to get rid of the exhalations from
drainage and to make certain that no whiff of any such vapours ever found
its way up any offset into his kitchen or any latrine or bathroom, he had
built in this small high tower a shaft reaching its top and full six feet
square all the way up. At its bottom it widened out into a chamber fully
twelve feet square, carried down below the level of the cellar floor to
form a cemented tank, vat, cistern or cesspool fully as deep as it was
wide. The outfall from this trap was by a terra-cotta pipe of considerable
size, its opening at such a point that the drain-water in the trap never
reached higher than a foot or so below the level of the cellar floor. The
various drainage-pipes from different parts of the villa were so led into
this trap-room that their lower ends were always under water, so that no
exhalations could ever pass up any of them.

To the bottom of the trap settled the solid matter and sediment from the
drainage-water. The trap was cleaned by slaves so often that the ooze in
it never rose high enough to escape down the outfall pipe