Note 10 — Chapter X · EFFECTS OF THE GREAT EXHIBITION OF 1851 IN IMPROVING ENGLISH LOCKS.

Mr. Denison informs us that there is a further contrivance, which he will explain privately to any persons who wish to manufacture these locks, of which the object is, not to add any thing to the security of the lock under ordinary circumstances, but to provide against the unusual case of a very dexterous thief having occasional access to the lock when open; in which case (but for some such further provision) he might manage to construct a false key capable of opening the lock at any other time, by a method which, for obvious reasons, it is not advisable to publish.