AFTER COMPLINE
In which, almost by chance, William discovers the secret of entering the finis Africae.

Like a pair of assassins, we lurked near the entrance, behind a column, whence we could observe the chapel with the skulls.
“Abo has gone to close the Aedificium,” William said. “When he has barred the doors from the inside, he can only come out through the ossarium.”
“And then?”
“And then we will see what he does.”
We did not discover what he did. An hour went by and he still had not reappeared. He’s gone into the finis Africae, I said. Perhaps, William answered. Eager to formulate more hypotheses, I added: Perhaps he came out again through the refectory and has gone to look for Jorge. And William answered: That is also possible. Perhaps Jorge is already dead, I imagined further. Perhaps he is to the Aedificium and is killing the abbot. Perhaps they are both in some other place and some other person is lying in wait for them. What did “the Italians” want? And why was Benno so frightened? Was it perhaps only a mask he had assumed, to mislead us? Why had he lingered in the scriptorium during vespers, if he didn’t know how to close the scriptorium or how to get out? Did he want to essay the passages of the labyrinth?
“All is possible,” William said. “But only one thing is happening, or has happened, or is about to happen. And at last divine Providence is endowing us with a radiant certitude.”
“What is that?” I asked, full of hope.
“That Brother William of Baskerville, who now has the impression of having understood everything, does not know how to enter the finis Africae. To the stables, Adso, to the stables.”
“And what if the abbot finds us?”
“We will pretend to be a pair of ghosts.”
To me this did not seem a practical solution, but I kept silent. William was growing uneasy. We came out of the north door and crossed the cemetery, while the wind was whistling loudly and I begged the Lord not to make us encounter two ghosts, for the abbey, on that night, did not lack for souls in torment. We reached the stables and heard the horses, more nervous than ever because of the fury of the elements. The main door of the building had, at the level of a man’s chest, a broad metal grating, through which the interior could be seen. In the darkness we discerned the forms of the horses. I recognized Brunellus, the first on the left. To his right, the third animal in line raised his head, sensing our presence, and whinnied. I smiled. “Tertius equi,” I said.
“What?” William asked.
“Nothing. I was remembering poor Salvatore. He wanted to perform God knows what magic with that horse, and with his Latin he called him “tertius equi: Which would be the u.”
“The u?” asked William, who had heard my prattle without paying much attention to it.
“Yes, because ‘tertius equi’ does not mean the third horse, but the third of the horse, and the third letter of the word ‘equus’ is u. But this is all nonsense. ...”
William looked at me, and in the darkness I seemed to see his face transformed. “God bless you, Adso!” he said to me. “Why, of course, suppositio materialis, the discourse is presumed de dicto and not de re. ... What a fool I am!” He gave himself such a great blow on the forehead that I heard a clap, and I believe he hurt himself. “My boy, this is the second time today that wisdom has spoken through your mouth, first in dream and now waking! Run, run to your cell and fetch the lamp, or, rather, both the lamps we hid. Let no one see you, and join me in church at once! Ask no questions! Go!”
I asked no questions and went. The lamps were under my bed, already filled with oil, and I had taken care to trim them in advance. I had the flint in my habit. With the two precious instruments clutched to my chest, I ran into the church.
William was under the tripod and was rereading the parchment with Venantius’s notes.
“Adso,” he said to me, “ ‘primum et septimum de quatuor’ does not mean the first and seventh of four, but of the four, the word ‘four’!” For a moment I still did not understand, but then I was enlightened: “Super thronos viginti quatuor! The writing! The verse! The words are carved over the mirror!”
“Come,” William said, “perhaps we are still in time to save a life!”
“Whose?” I asked, as he was manipulating the skulls and opening the passage to the ossarium.
“The life of someone who does not deserve it,” he said. We were already in the underground pass............