The following is adapted from The Masonic Conservators by Ray V. Denslow.
Come, my Brother, and let us build up the walls of Jerusalem, that we be no more a reproach. It was the practice of faithful Nehemiah, whenever a proper person came up from Babylon, and offered himself as a workman upon the walls, to take him by night around the city, show him every portion of the work, and allow him to select for himself that upon which he would labor. The whole was divided into ten parts designated as Gates.
The circuit being completed, the candidate was required to select for himself, unassisted, the Gate of his adoption. When he had done so, he was informed of his Conservator name, marked "Secret Name" in the chart below, and told that he could never afterwards change it.
This table shows the correspondance between Gates and secret names.