Complexity of action in any lock will sooner or later invariably prove fatal to its success. A lock is unlike a

MASTER-KEY OF THE DUBLIN INTERNATIONAL EXHIBITION, 1865.

watch or other delicate machine that is treated with a considerable amount of carefulness; it is subject to every day hard wear and usage. Absolute perfection is perhaps as unattainable in locks as in other matters; nevertheless the present is an age of progress, and a more perfect lock may perhaps be invented some day. Lock patents by scores have appeared within the last twenty-one years; some good, others indifferent or bad in principle, and many of them embracing as new ideas certain principles of construction long since exploded or laid aside. Of those practically defunct (and they are many), my opinion of them is that the ingenuity of the inventors has generally been allowed to over-run their perception of the before-mentioned fact, viz., that a lock is a very hardworked machine, and that in its construction simplicity is as necessary an element as security.

A good lock cannot have a key made to it unless another key is available to copy from or the lock itself can be broken open. Of this latter fact London burglars have not been slow to avail themselves, and they have tried it in the following manner. It should first be said, for those not acquainted with the mode of securing warehouse and office doors at night, where the buildings are left unoccupied, that such doors are usually fastened with a large rim or mortise lock of the ordinary kind. When this is locked from the outside a small flat bar, that is secured at one end to the door, is put across the keyhole to a staple thereon, fastened by a padlock. The advantage of this plan is that the inner lock cannot be touched, the keyhole being closed while the outer lock is secure; and this padlock being visible, the police in their rounds can tell by a glance under the light of the bull’s-eye whether or not it has been interfered with. But there is such a thing as forcing a padlock completely open, with proper appliances; and some clever burglar watching the policeman off his round past a warehouse in Watling Street, one night, wrenched the padlock off and supplied its place by a common one, the outside of which in the dark resembled the one previously on. He then took the patent lock away, got one side off, cut out all the works, so that anything like a key would at once open or close the bolt, fastened the side on as neatly as was possible, took it back to Watling Street again, and watching his opportunity took his own lock off and refixed the empty shell of the patent lock. The purpose in all this was that next night he might at once open the padlock, force the inner lock, and enter the place, while a confederate would doubtless

SPECIMENS OF ORNAMENTAL KEY HANDLES, REPRODUCED, BY PERMISSION, FROM ‘THE BUILDER.’

replace the padlock as if all were right. The success of the scheme depended chiefly upon the padlock or its substitute always being on when the police came round; but, fortunately for the owner of the premises, the attempt was frustrated by the mere chance of the patent lock (now without works and found next day to open rather stiffly) being brought to be examined, when the burglar’s attempt was at once discovered. Further revelations of this trick were made to the police by a convict who died while undergoing a long term of imprisonment, and after his disclosures no less than twenty-seven padlocks were found in use in the City the works of which had all been taken out, to await the thieves’ opportunity, and done in such a clever manner that only the closest inspection could detect it. Two of the locks served thus were on a jeweller’s door, which shows the importance of preventing this mode of robbery. Such a well-planned scheme required an improvement to be made in the padlocks, and there is now largely in use what is known as the ‘police padlock,’ a lock which when once forced asunder is so injured that it cannot be repaired without being entirely re-made, so that if one should be taken off its door by a thief it cannot be put back again.

This is but one of the numberless instances that require the attention and thought of the careful lockmaker; and the other instances that will be given show that with respect to safes it requires yet greater skill to foil the cunning of modern burglars.

The whole of Chubb’s locks are made by hand, and differ one from another. The difficulty is not to make them to differ, but when such are needed to make several alike, for a touch of the file will completely alter a lock.

It is so essential for good locks to be totally unlike each other that we continue to make by hand only, although the cost is in consequence high. Machinery would and does produce well-finished and serviceable locks, but the changes and combinations cannot vary as with hand-work. ‘So extensive are the combinations,[1] that it would be quite practicable to make locks for the doors of all the houses in London with a distinct and different key to each lock, and yet there should be one master-key to pass the whole. A most complete series was constructed some years ago for the Westminster Bridewell, consisting of 1,100 locks, forming one series, with master, sub-master, and warders’ keys.

‘At any time the Governor has the power of stopping out the under-keys; and in case of any surreptitious attempt being made to open a lock, and the detector being thrown, none of the under-keys will regulate it, but the Governor must be made acquainted with the circumstance, as he alone has the power, with his key, to replace the lock in its original state.

‘It need scarcely be stated, that Barron’s, Bramah’s, Chubb’s, and most other locks are adapted for all purposes, from the smallest cabinet to the largest prison-doors or strong-room.

‘As has been already stated, various and numerous patents have been taken out. Ingenious, however, as are some of the arrangements, they appear to have complicated, rather than simplified, the general construction.

‘It is submitted that the true principles of perfect security, strength, simplicity, and durability should be combined in every good lock.

‘1st. Perfect security is the principal point to be attended to, as without it no lock can be considered as answering the intended purpose.

‘2nd. The works of a lock should, in all cases, possess strength, and be well adapted, especially in the larger ones, to resist all attempts to force them open; and both in the larger and the