The Lucas Street depository was then (it has since been converted into a picture palace) generally accepted as being one of the strongest places in London. The front of the building was constructed to represent a gigantic safe door, and under the colloquial designation of "The Safe" the place had passed into a synonym for all that was secure and impregnable. Half of the marketable securities in the west of London were popularly reported to have seen the inside of its coffers at one time or another, together with the same generous proportion of family jewels. However exaggerated an estimate this might be, the substratum of truth was solid and auriferous enough to dazzle the imagination. When ordinary safes were being carried bodily away with impunity or ingeniously fused open by the scientifically equipped cracksman, nervous bond-holders turned with relief to the attractions of an establishment whose modest claim was summed up in its telegraphic address: "Impregnable." To it went also the jewel-case between the lady's social engagements, and when in due course "the family" journeyed north--or south, east or west--whenever, in short, the London house was closed, its capacious storerooms received the plate-chest as an established custom. Not a few traders also--jewellers, financiers, dealers in pictures, antiques and costly bijouterie, for instance--constantly used its facilities for any stock that they did not require immediately to hand. There was only one entrance to the place, an exaggerated keyhole, to carry out the similitude of the safe-door alluded to. The ground floor was occupied by the ordinary offices of the company; all the strong-rooms and safes lay in the steel-cased basement. This was reached both by a lift and by a flight of steps. In either case the visitor found before him a grille of massive proportions. Behind its bars stood a formidable commissionaire who never left his post, his sole duty being to open and close the grille to arriving and departing clients. Beyond this, a short passage led into the round central hall where Carrados was waiting. From this part, other passages radiated off to the vaults and strong-rooms, each one barred from the hall by a grille scarcely less ponderous than the first one. The doors of the various private rooms put at the disposal of the company's clients, and that of the manager's office, filled the wall-space between the radiating passages. Everything was very quiet, everything looked very bright, and everything seemed hopelessly impregnable. "But I wonder?" ran Carrados's dubious reflection as he reached this point. "Sorry to have kept you so long, my dear Max," broke in Mr. Carlyle's crisp voice. He had emerged from his compartment and was crossing the hall, deed-box in hand. "Another minute and I will be with you."