CHAPTER III.

LOCK CLASSIFICATION. THE PUZZLE-LOCK AND THE DIAL-LOCK.

In approaching the subject of modern locks it becomes necessary to decide upon some method of treating the widely-scattered and diverse materials which are presented to our notice. One plan would be to trace the subject chronologically, by describing, in the order of their invention, the most important locks which have been presented to public notice. But this would be attended with some disadvantages: the peculiar characters of the several locks would not be brought out with sufficient distinctness; and the result, so far as the reader is concerned, would rather tend to confusion than to a clear appreciation of the subject. There are more advantages belonging to a classification of locks under certain headings, according to some marked peculiarities in their modes of action. This is a convenient plan, but it is not an easy one to put in execution; for inventors have not sought to place their locks in any particular class, but rather to call attention to their merits. Moreover, many locks embody two or three distinct principles so equally, that it will often be difficult to decide in which class to place them. This, nevertheless, may be done with an approach to correctness. It is necessary first, however, to explain certain technical terms by which locks are distinguished one from another.

Locks, in truth, admit of an immense variety, which, however important to be known to locksmiths, carpenters, and others employed on them, need only be glanced at very cursorily by the general reader. Some locks are named according to the purposes to which they are to be applied; others according to their shape, or the principles of their construction. In the first place, there is the distinction between _in-door_ and _out-door_ locks. Of in-door locks, one principal kind is the _draw-back_ lock, for street-doors, in which the bolt is capable of maintaining any one of three positions: it may be locked by the key, or left half-way out by the pressure of a spring, or be drawn back by a handle. In the first position, it can only be withdrawn by the key; in the second, it closes the door, but can easily be withdrawn by the handle; and in the third, it leaves the door unfastened. If these locks are made of iron and carefully finished, they are further called _iron-rim_; but if made of wood, suitable for back-doors and inferior purposes, they are _spring-stock_. For the doors of rooms, there are the _iron-rim_, the _brass-case_, and the _mortise_ lock; the second supplants the first, and the third the second, as we advance in the elegance of the door-fittings. Other designations for room-locks depend on the number of the bolts: thus, if there be only one bolt, it is a _dead lock_ or _closet lock_; if there be a second bolt, urged by a spring and drawn back by a handle, it is a _two-bolt lock_; and if there be also a third, a private bolt acting only on one side of the door, it is a _three-bolt lock_. Again, according to the kind of handle employed, it may be a _knob lock_ or a _ring lock_. According to which edge of the door it is to be fixed, it becomes a _right-hand_ or a _left-hand_ lock. If the wards of the lock are of somewhat superior quality, and bend round nearly to a circle, the lock is _one-ward round_, _two-ward round_, and so forth. If the lock has no wards at all, it is _plain_; if the wards are of common character, they are often called _wheels_, and then the lock becomes _one-wheel_, _two-wheel_, &c. Sometimes the lock is named from certain fancied resemblances in the shape of the ward, as the L-_ward_, T-_ward_, or Z-_ward_. If the wards are cast in brass, instead of being made of slips of iron or copper, the lock is termed _solid ward_.

Of the numerous but smaller varieties known by the collective name of _cabinet locks_, there are the _cupboard_, the _bookcase_, the _desk_, the _portable desk_, the _table_, the _drawer_, the _box_, the _caddy_, the _chest_, the _carpet-bag_, and many other locks. All these locks are further called _straight_, when the plate is to be screwed flat against the wood-work; _cut_, when the wood is to be so cut away as to let in the lock flush with the surface; and _mortise_, when a cavity is excavated in the edge of the door for the reception of the lock.

Out-door locks are usually _wooden stock locks_, for stables, gates, &c.; comprising many varieties of _Banbury_, _bastard_, _fine_, &c. There are D _locks_ and P _locks_, for gates, designated from their shapes; and there are the numerous kinds of _padlocks_.

The above terms are employed chiefly between the makers of the locks and the persons who fix them in their places; but there are other terms and names, more familiarly known, which will come under notice in future pages.

It is scarcely worth while to descant upon the “middle age” of lock-making--to impart to the subject so much of dignity as to be susceptible of regular historical treatment. True, we know that _wards_ were employed before _tumblers_ (unless, indeed, the pins of the Egyptian lock be considered as tumblers--a character to which they present considerable claim), and that wards may be taken as the representative of the medieval period of lock-making; but it may be more profitable to proceed in our notice of the different kinds of locks in an order which will in itself partake somewhat of the historical character.

Apart from all the warded and tumbler locks are the very curious _puzzle_ or _letter-locks_; a construction which we propose to dismiss out of hand in the present chapter, before treating of those which have more commercial importance.

The puzzle-lock is generally in the form of a padlock, which is opened and closed without the use of a key, and which has certain difficulties thrown in the way of its being opened by any one who is not in the secret of the person who closed it. It is, in fact, one of the locks in which the doctrine of permutation is made to contribute to the means of security. The key to open it is a _mnemonic_ or _mental_ one, instead of one of steel or iron. Two centuries ago, the puzzle-lock attracted far more attention than any other. It has always certain movable parts, the movement of which constitutes the enigma. Some of these very curious and out-of-the-way locks are so formed as to receive the name of _dial-locks_; but the chief among them are _ring-locks_--a name the meaning of which will be presently understood.

The puzzle or letter-lock of the ring kind, then, consists essentially of a spindle; a barrel, encompassing the spindle; two end-pieces, to keep the spindle and barrel in their places; and the shackle, hinged to one of these end-pieces. To unfasten the lock, one of the end-pieces must be drawn out a little, to allow the shackle or horse-shoe to be turned on its hinge; and the question arises, therefore, how this end-piece is to be acted upon. This is effected in a very ingenious way: there are four studs or projections in a row on the spindle, and as the spindle fits pretty closely in the barrel, the former cannot be drawn out of the latter unless there be a groove in the interior of the barrel, as a counterpart to the studs on the exterior of the spindle; four rings fit on the barrel, on the interior of each of which there is a groove; and unless all these four grooves coincide in direction, and even lie in the same plane as the groove in the barrel, the studs will not be able to pass, and the spindle cannot be drawn out. Each ring may be easily made to work round the barrel by means of the fingers, and to maintain any position which may be given to it. There are outer rings, one over each of the rings just described, with the letters of the alphabet (or a considerable number of them) inscribed on each; and these outer rings, by means of notches on the inside, govern the movements of the inner rings.

The action is, therefore, as follows: when the padlock is to be locked, the rings are so adjusted that all the grooves shall be in a right line; the spindle is thrust in, the end-piece is fixed on, and the shackle is shut down. The padlock is now fastened; but a reverse order of proceeding would as easily open it again, and therefore the “safety” or “puzzle” principle is brought into requisition. The outer rings are moved with the finger, so as to throw the various interior grooves out of a right line, and thus prevent the withdrawal of the spindle. As each ring may be turned round through a large or a small arc, and all turned in different degrees, the variations of relative position may be almost infinite. The letters on the outer rings are to assist the owner to remember the particular combination which he had adopted in the act of locking; for no other combination than this will suffice to open the lock. There may, for instance, be the four letters L O C K in a line, which line is brought to coincide with two notches or marks at the ends of the apparatus; and until all the four outer rings are again brought into such relative position as to place the letters in a line, the lock cannot be opened.

There are many allusions to locks, apparently belonging to the letter or puzzle principle, in authors who flourished two or three centuries ago. Thus, in Beaumont and Fletcher’s play of the _Noble Gentleman_, written in the early part of the seventeenth century, one of the characters speaks of

“A cap-case for your linen and your plate, With a strange lock that opens with A·M·E·N.”

And in some verses by Carew, written about the same time, there is an analogy drawn, in which one of the things compared is--

“A lock That goes with letters; for till every one be known, The lock’s as fast as if you had found none.”

In the _Memorabilia_ of Vanhagen von Ense, written about the middle of the seventeenth century, a commendatory notice is given of a letter-lock, or combination-lock, invented by M. Regnier, Director of the _Musée d’Artillerie_ at Paris. “Regnier,” we are told, “was a man of some invention, and had taken out a patent for a sort of lock, which made some noise at the time. Every body praised his invention, and bought his locks. These consisted of broad steel rings, four, five, or eight deep, upon each of which the alphabet was engraved; these turned round on a cylinder of steel, and only separated when the letters forming a particular word were in a straight line with one another. The word was selected from among a thousand, and the choice was the secret of the purchaser. Any one not knowing the word might turn the ring round for years without succeeding in finding the right one. The workmanship was excellent, and Regnier was prouder of this than of the invention itself. The latter point might be contested. I had a vague recollection of having seen something of the sort before; but when I ventured to say so, my suspicions were treated with scorn and indignation, and I was not able to prove my assertion; but many years afterwards, when a book, which as a boy I had often diligently read, fell into my hands, Regnier’s lock was suddenly displayed. The book was called _Silvestri a Petrasancta Symbola Heroica_, printed at Amsterdam in 1682. There was an explanation at p. 254, attached to a picture; these were the words:--_Honorius de Bellis, serulæ innexæ orbibus volubilibus ac literatis circumscripsit hoc lemma--Sorte aut labore_.[3] However, neither luck nor labour would have done much more towards discovering the secret of opening Regnier’s locks, from the variety of their combinations; and their security seemed so great, that the couriers’ despatch-boxes were generally fastened with them.”

[3] “Honorius de Bellis wrote this inscription,--_By chance or by labour_,--round a lock composed of revolving rings graven with letters.”

This curious extract, which was brought forward by Mr. Chubb, in a paper on locks and keys (read before the Institution of Civil Engineers in 1850), seems to take away the credit from one (Regnier) with whose name the letter-lock has been most intimately associated. We shall presently explain, however, what it was that Regnier effected towards perfecting the letter-lock. In the meantime it may be interesting to note that the British Museum contains a copy of the work mentioned by Vanhagen. At the page indicated there is an engraving (a fac-simile of which is given in fig. 5) containing a drawing of a veritable puzzle or letter-lock; the lock consists of a cylinder or barrel, on which seven rings work; each of these rings is inscribed with letters, and the ends of the cylinder are grasped by a kind of shackle.

It was a natural result of the arrangement of the letter-lock, as invented (conjecturally) by Cardan, that only one particular word or cipher or key could be used in each lock; and it was to increase the puzzle-power of the lock that Regnier doubled all the rings, making each pair concentric, and enabling the user to vary the cipher at pleasure.

The principle of the letter-lock, when applied to doors, requires that sort of modification which renders it what is termed a _dial-lock_. There are to such a lock one or more dials, with a series of letters or figures stamped on them; there is to each dial a hand or pointer connected by a spindle with a wheel inside the lock; on the wheel is a notch which has to be brought to a certain position before the bolt can be moved. There are false notches, to add to the difficulty of finding the true notch in each wheel. To adjust the notches to their proper position, a nut on the back of the wheel is loosened, and the pointer is set at any letter or figure chosen by the user. The pointers and the dials perform the part of the outer rings, the wheels that of the inner rings; and it is easy to see that the same leading features prevail in the two kinds of lock, however they may differ in detail.

These dial-locks have not been numerous; they require wheel and pinion work within the body of the lock, which gives delicacy and complication to the mechanism. The letter padlock, be its merits great or small, is strong and durable, not liable to get out of order; and in so far as it requires no key or key-hole, it occupies rather a special position among locks. One of our great “merchant-princes” has been a letter-lock inventor, as the following will shew.

Early in 1852, Mr. William Brown, the distinguished member for South Lancashire, read a paper before the Architectural and Archæological Society of Liverpool, of much interest in relation to our present subject. His object was to describe a letter-lock which he had invented, and which had up to that time given high satisfaction. We cannot do better than transcribe the paper, as reported in one of the Liverpool Journals, with a few abridgments.

“As your society are desirous of seeing any improvements or attempts at them, I send you a stock-lock for inspection. The idea for its construction I took from a letter-padlock. I had a lock of this description made by Mr. Pooley twenty-five years ago, which has been in use ever since on Brown, Shipley, and Co.’s safe....

“Its advantages I conceive to be--First, it cannot be picked, for there is no key-hole. Second, it cannot be blown up by gunpowder, for the same reason. Third, you cannot drill through the door so as to reach the lock, for you are intercepted by a steel plate on which your tools will not act: thus you cannot introduce gunpowder that way to force the lock off. Fourth, you cannot bounce off the wheels in the interior with a muffled hammer, for vulcanised India-rubber springs resist this. Fifth, you cannot drill the spindles out, as their heads are case-hardened. Sixth, you cannot drive them in, for they are countersunk in the door about half-way through....

“Now let us set the lock to the word W O O D (any other four letters might be used). When you set the lock, make a private record of them, so that you may not forget them. If parties do not know your letters, nothing but violence, applied by some means or other, can enable them to get into your safe; for the lock will not open to any thing but its talisman. Take off all the large wheels and open the lock: you will see that the large wheels have a number of false chambers; if you get the spurs of the bolt into three real chambers and one false, you are as fast as ever, for all four must be right.

“Having placed your key and pointer outside the door to point to W on brass-plate No. 1, the small wheel inside obeys the same impulse; then maintain your small wheel steadily on this point, and the large wheel No. 1 will only fit on at the right place, the true opening compartment being opposite the spur of the bolt. It being necessary at the time you set your lock that it should be open, proceed with Nos. 2 and 3 in the same way, your pointer standing steadily at O. No. 4 is the same, the pointer being held steadily at D. You should then shoot your lock two or three times, to be sure you have made no mistake. Every time you shoot your bolts out, turn your wheels away from the true chamber, and see when you again turn your pointers to W O O D that your lock opens freely; it is the proof that you have made no mistake, and you may now venture to lock your safe. When you unlock the door, and find it necessary to leave it open for a time, you should shoot the bolts as if locked, and turn the wheels, so that no one may find what your real letters are; and again adjust them to their proper places, in order that the bolt may go back and enable you to re-lock. Once having locked the door and turned the wheels from your real letters, you need not trouble yourself with carrying the key, but leave it in any place beside the lock.

“I believe two wheels would make a perfectly safe lock; three would be quite so. I adopted four to make security doubly sure, as it would be impossible in any given time to work the changes. On two wheels by chance the lock might open; you can, however, calculate the chances against this; and also three or four, the false compartment on the outer rim being taken into calculation. * * *

“If this lock is of any value, it should be known; if it has weak points, let them be pointed out, and they may admit of a remedy; for we ought not to be led to believe a lock is safe which is not so.”

In relation to the “first advantage” which Mr. Brown not unreasonably supposed to be possessed by his lock--viz. that “it cannot be picked, because it has no keyhole”--we shall have something to say in a future page, where certain fallacies on this subject will be noticed. In the meantime we may remark, that it is not a little creditable that a leading Liverpool merchant should have invented a lock worthy of occupying a position on his own safe for a quarter of a century; for we may be quite certain that he would not have allowed the lock to maintain that post of honour unless it had really (so far as experience had then gone) served worthily as a safeguard to his treasures. And if it were possible to collect all the by-gone specimens of lock-oddities, we should probably find among them many highly-ingenious letter-locks; for supposing a man to have a mechanical turn of mind, a lock is by no means an unworthy medium for displaying it; the pieces of metal are so small as to be easily manageable at a small work-bench in a small room. The fondness for this sort of employment evinced by the unfortunate Louis XVI. of France led to the common remark, “He is a capital locksmith, but a very bad king.”

In an amusing article in the _Observer_, during the progress of the “lock controversy,” was the following paragraph relating to combination-locks of the letter or puzzle kind: “The French, in their exposition of 1844, availing themselves of the permutation principle, produced some marvels in the art; but the principle has not been adopted in this country. The _Charivari_ had an amusing quiz upon these locks when they first came out. It said the proprietor of such a lock must have an excellent memory: forget the letters, and you are clearly shut out from your own house. For instance, a gentleman gets to his door with his family, after a country excursion, at eleven o’clock at night, in the midst of a perfect deluge of rain. He hunts out his alphabetical key, and thrusts it into his alphabetical lock, and says A Z B X. The lock remains as firm as ever. ‘Plague take it!’ says the worthy citizen, as the blinding rain drives in his eyes. He then recollects that that was his combination for the previous day. He scratches his head to facilitate the movement of his intellectual faculties, and makes a random guess B C L O; but he has no better success. In addition to his being well wet, his chances of hitting on the right combinations and permutations are but small, seeing that the number is somewhere about three millions five hundred and fifty-three thousand five hundred and seventy-eight. Accordingly, when he comes to the three-hundredth he loses all patience, and begins to kick and batter the door; but a patrol of the National Guard passes by, and the disturber of the streets is marched off to the watch-house.”