Note 5 — Chapter VIII · THE LOCK CONTROVERSY: PREVIOUS TO THE DATE OF THE GREAT EXHIBITION.
Reading edition
“But is there not this danger, that at the same time we shall be giving lessons to the thieves? It is not very probable that they will seek instruction of us, or that they have any need of it; they are greater masters in the art of opening doors than we can pretend to be. Let us then learn the art of opening locked doors, in order that we may acquire that of securing them in such a way as to leave little or nothing to be feared on account of their security.”