from the upper level room in Canonbury Tower

Between Elizabeth and James I there is a capital letter followed by a chopping out of the plaster so that the following few letters are obliterated. ("Ay, there's the rub." --Hamlet) The capital letter was believed to be an F (for Francis?).

pages 58-61

...Mrs. Gallup had found several references to historic Canonbury Tower in the cipher and one was especially intriguing. When she heard we were going to England again, she wrote us asking that we make use of this information in any way we wished. "Certain old panels in the double work of Canonbury Tower saved valuable Mss" and "Now to reach rare papers, take panel five in B's tower room, slide it under fifty with such force as to gird a spring. Follow A, B, C, therein. Soon will the Mss. so much vaunted theme o' F's many books be your own."

Would you like to go with us and visit the Tower? Canonbury Tower is situated in the parish of Islington, on the outskirts of London. All that remains of this once imposing pile, is one huge tower surrounded by a modern building. Dating from the Norman Conquest, it has had a varied and interesting history. In the time of Henry VIII it became the property of the Crown, and from that time through the reign of Charles I, although several times leased to tenants, it was more or less a country retreat of royalty. It is said that the childhood of both Queen Elizabeth and Robert Dudley center about this place. One bit of its history taken from Tomlin's History of Islington is of interest. In 1616 it was leased by Lord and Lady Compton--the Earl and Countess of Northampton-- to Francis Bacon, the Attorney-General, for a term of 40 years "should he live so long." It was here that he received the Great Seal. Yet according to Miss Alicia Leith, no mention of this fact is made in any biography of Bacon. It was while he lived here that he was the tutor of James I's young sons, Princes Henry and Charles. In 1625 he surrendered the lease and since that time the Tower has been held by the heirs of the Earl of Northampton.
The Tower's chief interest to Baconians, aside from the fact that Francis Bacon lived there for nine years, is the "writing on the wall." Above the entrance to the upper room of the Tower are significant words "Baconian Room," and just inside this entrance, high above the lintel, is a curious inscription, in black letters, giving a list of the Kings and Queens of England, from William the Conquerer through Charles I. Between the names of Elizabeth and James is a space wide enough for several letters, but these letters, either from the wearing away of time or by intention have been defaced. There is, however, a distinct "F", and Nelson, in his history of the Parish written in 1811, gives it as "Fr". The list had apparently remained unnoticed until that time, and it is due to Baconian research that it has been given prominence.
At the time of our visit, the Tower was used as a club house, and we found it necessary to have a special permit from the representative of the Marquess of Northampton before we could be admitted. This we had no difficulty in procuring but the caretaker of the Tower, having been up until the wee small hours, because of a card party, was not ready to receive such early guests as we were, and we had to wait until he had finished breakfast. When he did appear, he was most polite and attentive. We soon had him convinced that we knew something of the history of the Tower and were deeply interested.
He took us first into a beautiful paneled rrom,and, while Dr. Prescott engaged him in conversation, my niece and I counted panels, pressing each within our reach to see if any seemed to be loose. But to no avail! Then we were conducted upstairs to yet another and more beautiful paneled room. Here again we went through the same performance, with the same results.
We had turned to leave the room, fearing we were taking too much of the caretaker's time, when he stopped us and said, "You seem so interested in these rooms, perhaps you would like to know that when this place was being made ready for the club to move in, a panel up there, beside the fireplace, became loose, and had to be taken down. Behind the panel they found a secret passage!"
Trying to appear only mildly excited, Dr. Prescott asked if this passage had been investigated.
"Oh no, sir. The panel was put back in place and sealed up."
On the first floor, in order to make the bar accessible to the card rooms, the thick walls of the Tower had been cut through, and here again was found a passage leading upwards and downwards into a subterranean region. Again we asked breathlessly if anyone had explored this.
"Oh no, sir," replied our guide, " they were afraid there would be bad air in there, so they just took a picture of the opening and sealed it up."
So there was a secret pasage behind the panel in the Baconian Room at Canonbury as the cipher had said! Later, a friend, to whom we told this story, said, "Can you imagine an American staying out of that place for fear of the "bad air?"
We also visited a place across the street from the Tower where recently a fruit tree had been blown down, disclosing a bricked-over place. An opening had been made and men had gone down into what was a passageway evidently leading to the Tower.
It was believed by some that it also led down under the river into London, but no investigation was made to find out. From the history of Bacon's time we find there were two subterranean passages, one under the river, the other to the gate of the Priory of St. John's in Clerkenwall. In the "Muniment room" over this gate, Sir Henry Tylney (for twenty-seven years Master of Revels) is said to have kept the properties for the Shakespeare Plays at the Bull Theatre near at hand in Bishopsgate Street.
The following year Mrs.Gallup returned to England and visited Canonbury Tower to prove, if possible, that the "fifth panel" could have been "pressed under the fiftieth." First, how was she to go about counting the panels? Where should she start? She decided the natural way would be to start in the upper left hand corner as she entered the door, counting from left to right, but it did not work out as she hoped. Finally, quite discouraged, she asked the attendant if he knew whether any changes had been made in this room any time. She was told that there had been, and that there were pictures of the room as it had formerly been. She was shown these pictures and found that the panel that we had been told had become loose was actually the fifth below the fiftieth.
Whether any curious Baconian will ever try to gain access to this secret passage, who can tell. There is today a very strong feeling among English Baconian scholars that the time has come when sentiment and the fear of disturbing old traditions should no longer stand in the way of following the many clues given in cipher. It is felt proof should be obtained once and for all showing whether the statements that the manuscripts have been so concealed is true.

SirBacon.org - Sir Francis Bacon's New Advancement of Learning