When the American locks became known in England, Mr. Hobbs undertook the superintendence of their manufacture, and their introduction into the commercial world. Such a lock as that just described must necessarily be a complex piece of mechanism; it is intended for use in the doors of receptacles containing property of great value; and the aim has been to baffle all the methods at present known of picking locks, by a combination of mechanism necessarily elaborate. Such a lock must of necessity be costly; but in order to supply the demand for a small lock at moderate price, Mr. Hobbs has introduced what he calls a protector lock. This is a modification of the ordinary six-tumbler lock. It bears an affinity to the lock of Messrs. Day and Newell, inasmuch as it is an attempt to introduce the same principle of security against picking, while avoiding the complexity of the changeable lock. The distinction which Mr. Hobbs has made between secure and insecure locks will be understood from the following proposition, viz. “that whenever the parts of a lock which come in contact with the key are so affected by any pressure applied to the bolt, or to that portion of the lock by which the bolt is withdrawn, as to indicate the points of resistance to the withdrawal of the bolt, such a lock can be picked.” Fig. 47 exhibits the internal mechanism of this new patent lock. It contains the usual contrivances of tumblers and springs, with a key cut into steps to suit the different heights to which the tumblers must be raised. The key is shewn separately in fig. 48. But there is a small additional piece of mechanism, in which the tumbler stump shewn at s in figs. 46 and 47 is attached; which piece is intended to work under or behind the bolt of the lock. In fig. 47, b is the bolt; t t is the front or foremost of the range of six tumblers, each of which has the usual slot and notches. In other tumbler-locks the stump or stud which moves along these slots is riveted to the bolt, in such manner that, if any pressure be applied in an attempt to withdraw the bolt, the stump becomes pressed against the edges of the tumblers, and bites or binds against them. How far their biting facilitates the picking of a lock will be shewn further on; but it will suffice here to say, that the movable action given to the stump in the Hobbs lock transfers the pressure to another quarter. The stump s is riveted to a peculiarly-shaped piece of metal h h (fig. 46), the hole in the centre of which fits upon a centre or pin in a recess formed at the back of the bolt; the piece moves easily on its centre, but is prevented from so doing spontaneously by a small binding spring. The mode in which this small movable piece takes part in the action of the lock is as follows: when the proper key is applied in the usual way, the tumblers are all raised to the proper heights for allowing the stump to pass horizontally through the gating; but should there be an attempt made, either by a false key or by any other instrument, to withdraw the bolt before the tumblers are properly raised, the stump becomes an obstacle. Meeting with an obstruction to its passage, the stump turns the piece to which it is attached on its centre, and moves the arm of the piece p so that it shall come into contact with a stud riveted into the case of the lock; and in this position there is a firm resistance against the withdrawal of the bolt. The tumblers are at the same moment released from the pressure of the stump. There is a dog or lever d, which catches into the top of the bolt, and thereby serves as an additional security against its being forced back. At k is the drill-pin on which the pipe of the key works; and r is a metal piece on which the tumblers rest when the key is not operating upon them.

Another lock, patented by Mr. Hobbs in 1852, has for its object the absolute closing of the key-hole during the process of locking. The key does not work or turn on its own centre, but occupies a small cell or chamber in a revolving cylinder, which is turned by a fixed handle. The bit of the movable key is entirely separable from the shaft or stem, into which it is screwed, and may be detached by turning round a small milled headed thumb-screw. The key is placed in the key-hole in the usual way, but it cannot turn; its circular movement round the stem as an axis is prevented by the internal mechanism of the lock; it is left in the key-hole, and the stem is detached from it by unscrewing. By turning the handle, the key-bit, which is left in the chamber of the cylinder, is brought into contact with the works of the lock, so as to shoot and withdraw the bolt. This revolution may take place whether the bit of the movable key occupy its little cell in the plate or not; only with this difference—that if the bit be not in the lock, the plate revolves without acting upon any of the tumblers; but if the bit be in its place, it raises the tumblers in the proper way for shooting or withdrawing the bolt. It will be understood that there is only one key-hole, namely, that through which the divisible key is inserted; the other handle or fixed key working through a hole in the cover of the lock only just large enough to receive it, and not being removable from the lock. As soon as the plate turns round so far as to enable the key-bit to act upon the tumblers, the key-hole becomes entirely closed by the plate itself, so that the actual locking is effected at the very time when all access to the interior through the key-hole is cut off. When the bolt has been shot, the plate comes round to its original position, it uncovers the key-hole, and exhibits the key-bit occupying the little cell into which it had been dropped; the stem is then to be screwed into the bit, and the latter withdrawn. It is one consequence of this arrangement, that the key has to be screwed and unscrewed when used; but through this arrangement the key-hole becomes a sealed book to one who has not the right key. Nothing can be moved, provided the bit and stem of the key be both left in; but by leaving in the lock the former without the latter, the plate can rotate, the tumblers can be lifted, and the bolt can be shot.

CHAPTER VIII.
THE LOCK CONTROVERSY: PREVIOUS TO THE DATE OF THE GREAT EXHIBITION.

It must be evident, even on a cursory glance at the past history of the lock-manufacture, that the prime motive for the introduction of novelties and improvements in construction is the desirability of producing a lock which no one can open without the proper key. From the earliest and simplest lock, down to the latest and most complex, this object has been constantly held in view; and every clear proof or evidence that this object has not been attained has led to the invention of some new contrivance. It has been a succession of struggles—to attain security—to shew that this security has not been attained—to make a further and more ingenious attempt—to detect the weak point in this renewed attempt—and so on. We need not repeat here, what was stated in an early chapter, that benefit must ultimately result from a candid discussion of this question. When M. Réaumur proposed to explain how the locks of his day could be picked or opened without the true key, his object was to shew to persons who were not locksmiths how far they could depend upon the principle of security offered by locks. But before proceeding on his inquiry, the illustrious naturalist asks, “Ne craindra-t-on pas que nous ne donnions en même tems des leçons aux voleurs?” And he replies, “Il n’y a pas grande apparence qu’ils viennent les chercher ici, et qu’ils en aient besoin; ils sont plus grands maîtres que nous dans l’art d’ouvrir les portes. Apprenons donc l’art d’ouvrir les portes fermées, afin d’apprendre celui de les fermer d’une manière qui ne laisse rien ou qui laisse peu à craindre.”[5]

Before treating of lock controversies and lock violability in England, it will be desirable first to refer to America, where this subject attracted much attention some years earlier than the Great Exhibition—an Exhibition which will always be associated in a remarkable manner with the history of locks.

Soon after the inventions by Dr. Andrews and Mr. Newell, in 1841 (described in a former chapter), the rivalry between the two locks ran high; each lock being ‘unpickable,’ according to the estimate of its inventor. Mr. Newell thought the best mode of shewing the superiority of his own lock would be by picking that of his competitor; and after several trials, he succeeded in bringing into practical application that system of picking which we may designate the mechanical, as contra-distinguished from the arithmetical. Mr. Newell not only picked Dr. Andrews’ lock, but he wound up the enterprise by picking his own! He was probably the first person who honestly confessed to having picked his own unpickable lock. This discovery led Mr. Newell, as has been noticed in a former page, to the invention of the triple-action or parautoptic lock.

The mechanical principle, as applied to the picking of a tumbler lock, is nearly the same whatever form of construction be made the medium of experiment. When a pressure is applied to the bolt sufficient to unlock it if the tumbler-obstructions were removed, the edges of the tumbler bite or bind against the stump of the bolt, so as not to move up and down with such facility as under ordinary circumstances. By carefully trying with a small instrument each tumbler, and moving it until the bite ceases, the gating of that particular tumbler may be brought to the exact position for allowing the stump of the bolt to pass through it. (See page 118.)

This violability is observable in the tumbler-locks under very varied forms of construction. Mr. Newell, after he had picked his own lock, devised a series of complicated wards, to add to the difficulty of reaching the tumblers; but he could not thereby get rid of the importance of this fact, that wherever a key can go, instruments of a suitable size and form could follow: his wards did not render his lock inviolable. His next contrivance was to notch the abutting parts of the primary and secondary tumblers, or the face of the stump and the ends of the tumblers; but this failed also. Mr. H. C. Jones, of Newark, N. J., added to all this a revolving pipe and curtain, to close as much of the key-hole as possible. But so far were all these precautions from being successful, that a lock provided with all these appendages, and affixed to the door of the United States Treasury at Washington, was picked. The makers of locks have, each one for himself, contended against such difficulties as were known to them at the time of inventing their locks; and, mortifying as failure may be, it would be cowardly to yield up the enterprise whenever any new difficulty presented itself. Difficulties, in locks as in other matters, are made to be conquered.

To shew how numerous are the sources of insecurity which have to be guarded against, to meet the skill often brought to bear upon this lock, we may adduce the reasons which led Mr. Newell to apply a curtain to the key-hole of his lock. Supposing the interior arrangement of the triple set of tumblers, and the metallic shielding wall, to be perfect, still, if the first set of tumblers can be seen through the key-hole, the following plan may be put in operation. The under-side of the tumblers may be smoked, by inserting a flame through the key-hole; and the key will then leave a distinct mark upon each tumbler the next time it is used, shewing where it began to touch each tumbler in lifting it. This may be seen by inserting a small mirror hinged into the lock through the key-hole. There may even be an electric light used from a small portable battery, to illumine the interior of the lock. By these and other means the exact length of each bit of the key may be determined; and from these data a false key may be made. It is to prevent this inspection of the works, or any other examination of an analogous kind, that the revolving curtain was applied; but, as stated in the last paragraph, even this did not suffice: ingenuity devised a mode of baffling the contrivance of curtains as well as that of the wards and false notches in the tumblers.

When the parautoptic lock was completed, it was keenly criticised in America, owing to the long discussions respecting the merits of previous locks. In a matter of this kind, where a commercial motive would lead bankers and companies to apply a very severe test to the security of locks and similar fastenings to strong-rooms and receptacles, any experiments made with their sanction became important. Mere letters or certificates emanating from individuals, expressive of opinions concerning a particular lock, would be out of place in a volume relating to locks generally; but it is quite within the limits of the subject, and has indeed become part of the history of locks, to notice experiments and attempts of a more public character. We may therefore introduce a few paragraphs of this description, relating to the career of the American lock in America itself.

The principal bankers at Boston (U.S.) held a meeting to take into consideration measures for testing the security of bank locks. Consequent on this meeting, Messrs. Day and Newell deposited five hundred dollars with the cashier of the State Bank at Boston, to be by him paid to any one who could pick the parautoptic lock: the trial was to be conducted under the auspices of the bank. One of the locks was brought to the bank, and was minutely examined by two machinists on two afternoons, after which it was secured to an iron chest, and locked by a committee appointed by the bank. The key was to remain in the hands of the committee during the trial; and it was to be used at their discretion, in unlocking and locking the door, without the knowledge of either of the other parties—provided that in so doing no alteration was made in the combination-parts of the key. Ten days were allowed to the operators for the examination and the trial; if they succeeded they were to have five hundred dollars; but if they injured the lock they agreed to forfeit two hundred, as a purchase price. At the end of the period the lock remained unopened and uninjured; and the two deposited sums were accordingly returned to the respective parties.

Messrs. Page and Bacon, of St. Louis, had a strong-room lock made by one of the chief locksmiths of that city. To test its security, the proprietors requested Mr. Hobbs to attempt to pick it; he did so, and succeeded. Whereupon the proprietors, having purchased one of the parautoptic locks, deemed it no more than fair play to subject this lock to a similar ordeal, an additional zest being given by a reward of five hundred dollars offered by Day and Newell to the successful picker. The maker of the former lock accepted the challenge; he was allowed to examine the new lock piecemeal, and was then allowed thirty days for his operations in picking. He failed in the enterprise. Of course, in this, as in all similar cases, the operator had not access to the true key.

It follows from the nature of this lock, as noticed in a former chapter, that when the bolt has been shot, if the bits of the key be re-arranged in any other form, the lock becomes to all intents and purposes a new lock, so far as that key is concerned, and cannot be unlocked unless the key revert to its original arrangement. To test this principle, a box with a parautoptic lock was placed in the room of the American Institute in 1845; it was locked; the bits of the key (12 in number) were then re-arranged, and the key was placed in the hands of any one who chose to try to open the lock—with the offer of a reward of five hundred dollars in the event of the lock being opened. Here, instead of the operator being called upon to devise new pick-lock implements, he had the actual key placed in his hands, modified however in such a way that, though the modifier could restore the original arrangement (provided he had kept some kind of record), the operator had numerous chances against his success. The lock remained unopened notwithstanding this challenge.

We shall have occasion to shew presently, that if the number of tumblers (and consequently the number of bits in the key) be small—not exceeding six, for instance—the possession of the true key gives any one the power of opening the lock, provided he has time and patience to go through a few hundred changes of the bits of the key; for, as some one arrangement must have been that by which the lock was locked, it must again occur if the user takes care to make all the arrangements in turn, and tries the lock after each. Whether this constitutes picking a lock, each lock-owner will decide for himself. All that it is at present meant to state is, that without access to the true key, the parautoptic lock has not hitherto been opened; and that with the true but altered key the process of opening is possible, but is slow and tedious.

In 1846 the American Institute appointed a committee to examine into the merits of the parautoptic lock. On the 18th of September in that year the Committee made their report, signed by Professor Renwick and Mr. T. W. Harvey, as follows:—

“The Committee of the American Institute, to whom was referred the examination of Newell’s Parautoptic Bank Lock, report that they have given the subject referred to them a careful and attentive examination, and have received full and complete explanations from the inventor. They have remarked in the lock a number of important advantages, and, in particular, very great improvements upon the permutation-lock formerly submitted by him to the American Institute. Thus, while it retains the advantages of the permutation principle, combined with the property that the act of locking sets the slides to the particular arrangement of the bits in the skeleton key, the parts thus set are completely screened from observation, from being reached by false instruments, or from being injured by any violence not sufficient to break the lock to pieces.

“Having in the course of their inquiries examined the different existing modes in which locks may be picked, forced, or opened by false keys, the Committee have come to the conclusion that the parautoptic lock cannot be opened by any of the methods now practised, unless by a person in possession of the key by which it was locked, in the exact form of combination in which it was used for the purpose, or in the almost impossible case of the bits being adjusted to the skeleton key by accident in that very form. As the chances of such accidental combination range according to the number of movable bits, from several thousands to several millions to one, the Committee do not conceive that so small a chance of success would ever lead to an attempt to profit by it.

“In conclusion, the Committee feel warranted in expressing the opinion, that unless methods hitherto unknown or imagined should be contrived for the specific object, the lock in question may be considered as affording entire and absolute security.”

The latest form which Messrs. Day and Newell have given to their challenge, after the experience of the last few years, is the following:

“First, a Committee of five gentlemen shall be appointed in the following manner: viz. two by the parties proposing to operate, and two by ourselves; and by the four thus appointed a fifth shall be selected.

“In the hands of this Committee shall be placed Two Thousand Dollars, as a reward to the operator if successful in picking the lock by fair means.

“We will place upon the inside of an iron door one of our best bank locks. The operator shall then have the privilege of taking the lock from the door, and have it in his possession for examination; it shall then be returned to the Committee for our inspection, so that we may be assured that it has not been mutilated or injured. The operator shall then, in the presence of ourselves and the Committee, place the lock upon the door in its original position; after which the Committee shall place upon it their seals, so that it cannot be removed or altered without their knowledge. The lock being thus secured to the door, we shall then be allowed to lock it up ourselves, upon any change of which it is susceptible.

“The time for operation to continue thirty days; and if at the end of that time he shall consider that he has made any progress towards picking the said lock, he shall have thirty days more in which to continue operations.”

The Austrian report concerning the American lock was given in a former page, to which we may here refer; and then direct attention to England, and to the discussions which have lately been carried on respecting the safety of locks.

It is of course natural that each inventor of a new lock should, while describing the product of his ingenuity, point out what he conceives to be the imperfections of locks which have preceded: use has sanctioned the custom not only with regard to locks, but also in other important matters. Hence there have been many “lock controversies” in England during the last seventy years. We have seen how freely and justly the late Mr. Bramah criticised all the locks that preceded his own; and he was certainly not the man to shrink from criticism in his own case. Twenty years ago the Bramah lock was itself made the subject of criticism.

Mr. Ainger, in his lecture on the subject delivered at the Royal Institution, London, and afterwards in his article “Lock” in the Encyclopædia Britannica, thus narrates the circumstances which led to the adoption of the false notches in the Bramah lock as a means of security: “At length (after the original lock had acquired much celebrity,) an advertisement appeared in the public papers, requesting those who had lost keys of Bramah’s locks, not, as had hitherto been done, to break open their doors or drawers, but to apply to the advertiser, who would undertake to save this destructive process by picking. And it appeared that an individual of great dexterity could perform this operation almost with certainty. The effect of this discovery on the demand for the locks may easily be imagined; but the effect it had in stimulating ingenuity to provide a remedy is one of the best illustrations of the proverb, that necessity is the mother of invention. Within a few days or weeks, Mr. Russell, who was at that time employed in Mr. Bramah’s establishment, devised an alteration which at once, and without any expense, entirely overcame the difficulty, and converted the lock into one of perfect security. This contrivance is the most simple and extraordinary that ever effected so important an object; but before we describe it, we will endeavour to explain what has been called the tentative process of lock-picking, and which had been so successfully applied to Bramah’s locks.”

Mr. Ainger illustrates the subject by an engraving—not of an actual lock, but of an hypothetical arrangement of bolts and notches; and he then makes his reasoning apply to the actual process adopted by the picker of the real lock. “A tendency to revolve was given with some force to the barrel; then, by means of a pair of small forceps, the tumblers (sliders) were tried, and it was ascertained which one was most detained by the pressure against the locking-plate. That which offered most resistance was gradually depressed till its notch was felt to hang itself upon the locking-plate; and so on till the whole were depressed in succession, exactly as they would have been depressed simultaneously by the key.” Mr. Ainger then describes the contrivance which, in his judgment, seemed to render any further attempts to pick the Bramah lock hopeless. This consisted in cutting false notches in the sliders; so as to render it impossible for the picker to tell when he has brought a notch to the plane of the locking-plate, whether it is a true notch, or one of shallower depth, unfitted to admit the movement of the plate.

This is a very interesting statement, for it shews that the mechanical or tentative method of opening was known in England long ago, although very little attention has been since paid to it. In a complex Bramah lock, and in locks on the combination principle, the difficulty of picking is almost insuperable, so long as what may be termed the arithmetical method is adopted. It is perfectly true, as has been so often stated, that the varied combinations in the arrangement of the slides amount to millions and even billions, when the slides are in any degree numerous; and if a person attempt to pick the lock by ringing the changes on all these combinations, it would very likely require the lives of a dozen Methuselahs to bring the enterprise to an end. But by the mechanical method, sketched so clearly by Mr. Ainger, the exploit puts on a different aspect. The experimenter passes through the keyhole an instrument so arranged as to give a tendency in the bolt to withdraw in the wished-for direction; and a pressure produced in the slides by this tendency gives information concerning the state of the slides; and then comes the tentative process on the slides themselves. Mr. Ainger was quite right in describing the false notches as an admirable addition to the safety of the Bramah lock; but he was not correct in stating that these notches rendered any further attempts on the lock hopeless. The false notches are not so deep as the true; they will permit the barrel to turn partially but not wholly round. But even supposing that the false notch had been hit upon in nearly every slide instead of the true, and that the barrel had been partially turned to the extent which these notches permitted, there would then be a binding action at the false notches different from that in the true, and this would guide the operator in his search for the true notches. It would not add a new principle different from the one before in action, but it would add to the time during which the search would have to be carried on.

We make these remarks in connection with Mr. Ainger’s article, which was probably written twenty years ago. We now come to the year 1850.

At the meeting of the Institution of Civil Engineers, when Mr. Chubb’s paper was read, many challenges and counter-challenges were made, as to the possibility of picking certain locks. Mr. Chubb described, among others, a lock on the patent of Mr. Davies, which, ingenious though it be, he considers not safe. Captain D. O’Brien differed from Mr. Chubb in this matter; he had had occasion to open from ten to twenty of Davies’s cabinet-locks daily, during a period of two years, and he never once observed the locks to be out of order; in fact, they always appeared to afford great security. Mr. Chubb thereupon rejoined, that he was prepared to produce a workman who would pick any number of Davies’ cabinet-locks, of different combinations, which he had never seen before, taking only half an hour for each lock.

As another instance, Captain O’Brien stated that, in his capacity as Inspector of Government Prisons, his attention had been much directed to the subject of secure locks; and he produced, among others, specimens of those in use at the Pentonville Prison; though not of first-rate workmanship, he characterised them as being safe, strong, and cheap. They were on Thomas’s principle. The locks had been in use eight years, during which period not one had required to be replaced; and any trifling derangements had been made good whilst the prisoners were at exercise. Mr. Chubb, after making his offer concerning Davies’s lock, stated that “he was willing to make the same offer with respect to the locks from the Pentonville Prison; and he might state that, in point of security, he considered them absolutely worthless;” in proof of which he exhibited one of them, and a common burglar’s tool, by which the lock could be opened with the greatest ease.

In respect to Bramah’s lock, there was no particular challenge associated with the proceedings of the evening; but incidental observations were made as to the degree of security pertaining to it. Mr. Farey, after passing a high eulogium on the ingenuity of the principle and the beauty of the workmanship, considered it nevertheless objectionable that the sliders should be so completely exposed to view. He then proceeded to make the following observations: “It had been suggested, that a universal false key for Bramah’s locks might be made, with the bottoms of its several notches formed by as many small steel sliders, extending beyond the handle of the key, so as to receive pressure from the fingers, for moving each one of the sliders within the lock, with a sliding motion in its own groove, independently of the other. During such sliding motion, a gentle force could be exerted, tending to turn the barrel round. Under such circumstances, supposing that the motion of the barrel was prevented by any one slider only; that one, having to resist all the turning force, would be felt to slide more stiffly endways in its groove, and therefore it could be felt when its unlocking notch arrived opposite the steel plate, and left some other slider to begin to resist the turning force. Such a circumstance (continues Mr. Farey) presumes a palpable inaccuracy in the radiating correspondence between the notches in the steel plate and the grooves for the sliders in the barrel, which could not happen with Bramah’s workmanship.”[6] He further remarked: “Unfortunately, if a Bramah’s key fell into dishonest hands, even for a short time, an impression could be easily taken, and a false key as easily made. A turkey-quill, notched into the form of a key, had sufficed to open a Bramah’s lock; and an efficient false key could be formed out of a pocket pencil-case. Such facility of fabrication was an invitation to dishonesty; and as an abortive attempt left no trace, the impunity was an encouragement to repeat the attempt until success is attained.”

With respect to Chubb’s locks, a discussion arose out of a statement made by Mr. Hodge. Mr. Chubb had himself stated it to be a general opinion that a skilful workman, furnished with impressions taken from the true key, in wax or soap, could make a false key to open any lock; and he considered that, in common locks, with the most elaborate wards, but with only one tumbler, as also in Bramah’s locks, there was much truth in the notion. In respect to his own lock, however, with six double-acting tumblers, “a false key made ever so carefully from impressions would not be likely to open the lock, for want of exactitude in the lengths of the several steps; and if the key could not be made exact from the impressions, there would be no chance of rectifying it by trial in the lock, on account of the total uncertainty as to which part required alteration.” Mr. Hodge stated that, in America, he had repeatedly seen impressions taken of locks having twelve or fourteen tumblers, in consequence of the bellies of the tumblers, when at rest, coinciding with the form of the key (see page 63). He also suggested a method of taking an impression of the bellies of the tumblers; but Mr. Chubb, Mr. Farey, Mr. Stephenson, and Mr. Whitworth, all expressed a disbelief that a Chubb’s lock could be opened by the means indicated by Mr. Hodge. Mr. Hodge admitted that he was not aware of any lock actually made by Messrs. Chubb having been picked in America; but that the locks to which he had adverted were such exact imitations, that he had no doubt of the Chubb lock yielding to similar treatment. He further stated that there were persons in New York who would undertake to pick a real Chubb lock.

CHAPTER IX.
THE LOCK CONTROVERSY: DURING AND SINCE THE TIME OF THE GREAT EXHIBITION.

We next come to the remarkable year 1851, which produced so many unexpected results in connection with the industrial display in Hyde Park, and conferred a lasting benefit on the useful arts and manufactures of the United Kingdom, by bringing their products into contrast and competition with those of other nations. It was to be expected that such a trial as this would afford evidences of national failure as well as of success; but probably no one suspected before the trial, that English locks, so celebrated over the greater part of the world for skilful mechanical design, beauty of workmanship, and perfect inviolability, would readily yield to a well-arranged system of lock-picking. Such, however, was the case; and we are bound to admit that Mr. Hobbs, the author of this system, is a mechanician of great skill, and with a profound knowledge of the art of the locksmith.

The first step in the celebrated lock controversy of 1851 was taken by Mr. Hobbs himself, who declared to a party of scientific men in the Crystal Palace, that all the locks made in this country up to that date admitted of being very easily picked; and in order to explain to these gentlemen the principle upon which this was to be done, Mr. Hobbs picked one of Chubb’s patent detector-locks in their presence in a few minutes.

The fairness of this experiment having been called in question by certain persons who were not present at the time when it was made, Mr. Hobbs, on July 21st, 1851, wrote a letter from the American department of the Great Exhibition, to Messrs. Chubb, simply announcing that an attempt would be made, on the next following day, to pick a lock manufactured by them, and which was at that time on the door of a strong room in a house named by Mr. Hobbs. Messrs. Chubb were invited to be present at the operation; but no member of the firm attended. What occurred on the day specified may best be given in the words of a letter written by those who witnessed the operation.

“London, July 22, 1851.

“We the undersigned hereby certify, that we attended, with the permission of Mr. Bell, of No. 34 Great George-street, Westminster, an invitation sent to us by A. C. Hobbs, of the City of New York, to witness an attempt to open a lock throwing three bolts and having six tumblers, affixed to the iron door of a strong-room or vault, built for the depository of valuable papers, and formerly occupied by the agents of the South-Eastern Railway; that we severally witnessed the operation, which Mr. Hobbs commenced at 35 minutes past 11 o’clock A.M., and opened the lock within 25 minutes. Mr. Hobbs having been requested to lock it again with his instruments, accomplished it in the short space of 7 minutes, without the slightest injury to the lock or door. We minutely examined the lock and door (having previously had the assurance of Mr. Bell that the keys had never been accessible to Mr. Hobbs, he having had permission to examine the key-hole only). We found a plate at the back of the door with the following inscription: ‘Chubb’s New Patent (No. 261,461), St. Paul’s Churchyard, London, Maker to Her Majesty.’”

This letter was signed with the names and addresses of the following gentlemen:—

Several of these names are well and publicly known in England and the United States.

This event gave rise to much newspaper controversy; and attempts were made to shew that, as this was not a test lock, prepared expressly for challenge, the picking proved nothing as regards the finest of the manufacturers’ locks. Two circumstances, however, have to be noticed—that the lock was of sufficient commercial importance to be placed on a door enclosing valuable papers, and that the makers had an opportunity to attend and witness, and comment on the trial, if they so chose. We may here remark, that one of the ingenious contrivances of the Chubb lock, the detector, excited some doubt no less than fifteen years ago, as will be seen from the following. The writer of the article “Lock” in Hebert’s Engineers’ and Mechanics’ Encyclopædia, while speaking with much commendation of Chubb’s locks, points out a curious feature, which seems to him to render somewhat doubtful the surety of the detector apparatus. “In Barron’s and Bramah’s locks,” he observes, “the picker has no means of knowing whether the tumblers are lifted too high or not; but in Chubb’s he has only to put the detector hors de combat in the first instance, by a correct thrust from the outside of the door (which might be accurately measured), so as to fix it fast in its place; the detector then becomes a stopper to the undue ascent of the tumblers, and the extent of their range is thereby correctly ascertained. Thus, it appears to us, the detector might be converted into a director of the means for opening the lock.”

Much will depend on the view which is taken of the circumstance just noted. The object of the detector is, not to prevent the lock from being picked, but to shew that an attempt has been made to pick it; or, at least, to attain a given purpose by an indirect instead of a direct method. But if there be really any truth in the surmise, that the detector actually guides a skilful hand in determining how high the tumblers should be raised, the supposed advantage will be purchased at rather a dear rate. As we are here, however, speaking of facts and not of mere opinions, it is proper to say, that the lock opened by Mr. Hobbs had the detector apparatus, but that it was not disturbed by him in picking the lock.

But instead of reiterating opinions, we will state the method by which most of the tumbler-locks made in England, up to the date of the Great Exhibition, can be opened or picked.

Bearing in mind the principle on which the picking of locks is said to depend, namely, that “whenever the parts of a lock which come in contact with the key are affected by any pressure applied to the bolt, or to that portion of the lock by which the bolt is withdrawn, in such a manner as to indicate the points of resistance to the withdrawal of the bolt, such a lock can be picked,” the first step is to produce the requisite pressure.

If the end of the bolt were exposed, this pressure might be applied by some force tending to shoot back the bolt; but as the bolt, whenever it is shot, is buried in the jamb of the door, or otherwise concealed from view, the pressure can in general only be applied through the key-hole. In order, therefore, to apply this pressure, the operator provides himself with an instrument capable of reaching the talon of the bolt, which in the case of the Chubb lock was a pipe-key of the form shewn at a b, fig. 49, furnished at the pipe-end with that portion of the bit of the key b c which moves the bolt (see fig. 32, page 57, where the step which acts on the bolt is called the terminal step). The other end of the pipe-key is made square, as at a, for the purpose of receiving the square eye e of the lever e f, fig. 50, to the further end of which f a weight w is attached by means of a string s. Now it is evident that if this pipe be introduced into the lock as far as it will go, and be turned round as in the act of unlocking, and the lever and weight be attached to the end a, the bit b c of the pipe-key will maintain a permanent pressure on the bolt, which, if the weight be sufficient, will throw back the bolt as soon as the tumblers are raised to the proper height to allow the stump to pass.

The next step in the operation is to raise the tumblers to the proper height. For this purpose a second pipe m n is made to slide upon the first with an easy motion, and by means of the cross handle h h can be turned round or slid backwards and forwards on the tube a b. This tube m n is also furnished with a single projecting bit or step n o, corresponding with one of the six steps of the key, fig. 32, and made of the proper length for entering the key-hole.

Now for the operation of opening a tumbler-lock with this simple apparatus. Referring to fig. 31, page 56, it will be evident that if the pipe a b, fig. 49, be passed over the pin of the lock and turned round towards the left, and the weight be attached, there will be a tendency in the bolt to shoot back, which tendency will bring the stump s, fig. 31, up against the inner angle or shoulder of one or other of the tumblers, whichever happens to project, however slightly; or, as Mr. Hobbs expresses it, “one or more of the tumblers will bind.” By moving forward the pipe m n and turning round the bit n o in the lock, it is easy to ascertain, by delicate touch, which of the tumblers it is that binds. It may be found that all are free to move except one or two against which the stump is pressing with the force of the weight w, fig. 50. The bit n o is therefore brought gently under the bellies of the tumblers which bind, and they are moved slightly upwards until they cease to bind. As soon as they are set free another tumbler will bind; that is, the bolt will move through a small space, so as to bring the stump into contact with that particular tumbler which now projects; this in its turn is relieved, another tumbler binds and is relieved, and so on until the tumblers are, one by one, raised to the proper height for the stump to pass. When the last binding tumbler is raised to the proper height, the weight w being no longer resisted, shoots the bolt back, and the work is done.

Now it must be evident that in this operation the detector apparatus need not come into operation. But if, as has been proposed, a detector-spring be added to each tumbler, it may be converted into a friend or a foe according to the use that is made of it. If the tumblers are lifted too high, they will be detained or detected in that position, and the operator will have to release them by turning the bit round in the opposite direction before he can begin his work again. The same force, however, which detains the tumblers when they are lifted too high will obviously detain them when they are lifted only just high enough, and thus the detector-springs would really be of great assistance to the operator in picking such a tumbler-lock.

The apparatus which we have described for picking the tumbler-lock must be varied to suit the form of key employed in opening the lock; but it is not difficult, in the case of most locks, to ascertain this form through the key-hole, without examining the key itself.

It is but fair to state in this place, that since the above method of picking tumbler-locks was made known,[8] Mr. Chubb has added a series of teeth and notches to the stump and tumblers; the effect of which would evidently prevent the application of the above method of picking, because any permanent pressure applied to the bolt would send a tooth of the stump into a notch of the tumbler, and prevent all further motion. But recurring to the principle, that whenever the parts of a lock which come in contact with the key indicate the points of resistance when any pressure (whether permanent or temporary) is applied in attempting to withdraw the bolt, that lock can be picked, it follows, if this principle be admitted, that although the notches prevent the application of the form of instrument described, yet there is sufficient indication afforded by the pressure to enable a skilful operator, with proper instruments, to form a false key, as was done in the case of the lock referred to at page 104. We now proceed to the second stage in the lock controversy of 1851.