CONTENTS.
| CHAP. | PAGE | |
|---|---|---|
| I. | On Locks and Lock-literature | [1] |
| II. | Ancient Locks: Grecian, Roman, Egyptian | [8] |
| III. | Lock classification. The Puzzle-Lock and the Dial-Lock | [16] |
| IV. | Warded Locks, with their varied appendages | [27] |
| V. | On Tumbler or Lever Locks | [43] |
| VI. | The Bramah Lock | [64] |
| VII. | American Locks | [82] |
| VIII. | The Lock Controversy: previous to the date of the Great Exhibition | [102] |
| IX. | The Lock Controversy: during and since the time of the Great Exhibition | [115] |
| X. | Effects of the Great Exhibition of 1851 in improving English Locks | [140] |
| XI. | The Lock and Key Manufacture | [154] |
| XII. | English Patents for Locks. Aubin’s Lock Trophy. Conclusion | [164] |
| Appendix. | ||
| XIII. | On an Improved Construction of Lock and Key: Fenby’s Adytic Lock | [176] |
| XIV. | Fenby’s Stop Lock | [193] |
| XV. | Note upon Iron Safes | [201] |
ON THE
CONSTRUCTION OF LOCKS.
CHAPTER I.
ON LOCKS AND LOCK-LITERATURE.
The manufacture of locks, and a consideration of the mechanical principles involved in their construction and security, have never yet been treated with any degree of fulness in an English work. Lock-making has occupied a large amount of ingenuity, and lock-patents have been obtained in considerable number, though not always, we are satisfied, with a commensurate return for the expense incurred,—but lock-philosophy (if so it may be designated) has not been largely attended to.
And yet it may safely be said that much which is both mechanically and commercially important is comprised in a lock. Every improvement in the manufacture of iron, steel, and brass—that is, in the tool-making and machine-making processes—may be made to reflect its light on the lock-manufacture; the stamping, the casting, the planing, the slotting, the screw-cutting, the polishing of metals,—all, in proportion as they are improved, impart some of their aid to the lock-maker. Then, in the finer kinds of locks, the works are so delicate as to approach to the nicety of clockwork; thereby combining the manipulative skill of a talented artisan with the rougher mechanical work of the smith. The principles of mechanical science are also appreciated by many lock-makers. The lever, the inclined plane, the eccentric, the cam, the screw, the wheel and pinion, the ratchet, the spring,—all are brought to bear on the internal mechanism of locks, frequently in many novel combinations.
The commercial importance of locks—though of course never seriously questioned when once fairly brought before one’s attention—has been recently rendered so apparent as to have risen to the position of a public topic. If a strong room, containing gold and silver, notes and bills, books and papers—if such a room be necessarily shielded from intrusion, it becomes no less necessary that the shield should be really worthy of its name, trusty and reliable: a good lock is here nearly as indispensable as a faithful cashier. And without dwelling on such an auriferous picture as a room fall of gold, we shall find ample proof of the commercial importance of lock-making in the ordinary circumstances by which we are every day surrounded. Until the world becomes an honest world, or until the honest people bear a larger ratio than at present to the dishonest, the whole of our movables are, more or less, at the mercy of our neighbours. Houses, rooms, vaults, cellars, cabinets, cupboards, caskets, desks, chests, boxes, caddies,—all, with the contents of each, ring the changes between meum and tuum pretty much according to the security of the locks by which they are guarded.
A commercial, and in some respects a social, doubt has been started within the last year or two, whether or not it is right to discuss so openly the security or insecurity of locks. Many well-meaning persons suppose that the discussion respecting the means for baffling the supposed safety of locks offers a premium for dishonesty, by shewing others how to be dishonest. This is a fallacy. Rogues are very keen in their profession, and know already much more than we can teach them respecting their several kinds of roguery. Rogues knew a good deal about lock-picking long before locksmiths discussed it among themselves, as they have lately done. If a lock—let it have been made in whatever country, or by whatever maker—is not so inviolable as it has hitherto been deemed to be, surely it is to the interest of honest persons to know this fact, because the dishonest are tolerably certain to be the first to apply the knowledge practically; and the spread of the knowledge is necessary to give fair play to those who might suffer by ignorance. It cannot be too earnestly urged, that an acquaintance with real facts will, in the end, be better for all parties. Some time ago, when the reading public was alarmed at being told how London milk is adulterated, timid persons deprecated the exposure, on the plea that it would give instructions in the art of adulterating milk; a vain fear—milkmen knew all about it before, whether they practised it or not; and the exposure only taught purchasers the necessity of a little scrutiny and caution, leaving them to obey this necessity or not, as they pleased. So likewise in respect to bread, sugar, coffee, tea, wine, beer, spirits, vinegar, cheap silks, cheap woollens—all such articles as are susceptible of debasement by admixture with cheaper substances—much more good than harm is effected by stating candidly and scientifically the various methods by which such debasement has been, or can be produced. The unscrupulous have the command of much of this kind of knowledge without our aid; and there is moral and commercial justice in placing on their guard those who might possibly suffer therefrom. We employ these stray expressions concerning adulteration, debasement, roguery, and so forth, simply as a mode of illustrating a principle—the advantage of publicity. In respect to lock-making, there can scarcely be such a thing as dishonesty of intention: the inventor produces a lock which he honestly thinks will possess such and such qualities; and he declares his belief to the world. If others differ from him in opinion concerning those qualities, it is open to them to say so; and the discussion, truthfully conducted, must lead to public advantage: the discussion stimulates curiosity, and the curiosity stimulates invention. Nothing but a partial and limited view of the question could lead to the opinion that harm can result: if there be harm, it will be much more than counterbalanced by good.