The latest devices to outwit thd scientific burglar were described by Mr. H. Emory Chubb, one of the managing directors of the firm of locksmiths and safemakkers of that name, in a lecture illustrated by cinematograph at the Royal Society of Arts on "Recent Developments in the Manufacture of Safes and Strong Rooms."
Describing the ''anti-blowpipe"' type of safe, built on the understanding that it could be left, fully loaded, over a week-end, to resist the use of both liquid explosives and cutting flame, whether generated by gas or electricity, Mr. Chubb said the principle in its construction was that the actual strength of the safe should be the lash thing to be attacked. They were now building their heaviest safes with the strongest plates inside. Thus the outer plate changed its position and became the inner line of defence. The advantages were Obvious, for as the attack proceeded so the difficulties increased, the burglar's area for operation diminished, and his field of vision became less.
In strong rooms, provided there were good strong walls properly designed, the one weak spot which had to be blocked up was the doorway. In the new design the door itself consisted of a hollow cost steel manganese box two inches thick all over and about two feet deep. Externally this was very accurately machined so as to ensure that it made a metal to metal joint with its surrounding frame, which was least in and piece out of the same metal. The interior of the box was filled up to a depth of about 16 inches with the doorplate of armour-plate and unburnable alloy, together with its additional flame-resisting covering.
In front of the flame protector and directly behind the two-inch slab of manganese steel was placed an electric screen, which gave an alarm on being penetrated by any method. The driving mechanism of the bolts wag controlled by four keyless combination locks, which could be used either singly or in pairs. An additional control was given by a time lock, containing four chronometer movements. It could be set in such a way that it would not permit of the door being opened, even by those in possession of the combination, until the prearranged hour. This lock was invented in consequence of a burglary, when a bank manager disclosed his combination at the point of a revolver.
Text read from the printed page and cleaned; old type leaves the occasional error.