Soon after the picking of the Chubb lock in Great George-street, and consequent on the excitement and discussion to which that operation led, a committee, consisting of Mr. G. Rennie, Professor Cowper,[9] and Dr. Black, agreed to superintend the arrangements for a more severe testing of Mr. Hobbs’s power to open locks. There had been for many years exhibited in the window of Messrs. Bramah’s shop, in Piccadilly, a padlock of great complexity and beauty; to which an announcement was affixed, that a reward of two hundred guineas would be given to any person who should succeed in picking that lock. This challenge was accepted by Mr. Hobbs; and the committee managed all the arrangements, as arbitrators between Mr. Hobbs on the one side and Messrs. Bramah on the other. The lock was removed to an upper room in Messrs. Bramah’s establishment; where it was placed between two boards, and so fixed and sealed, that no access could be obtained to any part of it except through the key-hole. The room was to be given up to Mr. Hobbs; he was not to be interrupted by the presence or entrance of any other persons; and he was allowed a period of thirty days for opening the lock. If the lock was not picked at the expiration of that period, Mr. Hobbs was to be considered as having failed in his attempt.

There was much negotiation and correspondence before and during Mr. Hobbs’s operation on this lock. On July 2, he, with a view to this enterprise, applied for permission to take wax impressions of the key-hole. This permission being given, and the parties having met to discuss the necessary arrangements, an agreement was signed on the 19th, reciting the terms of the challenge, and providing that thirty days should be allowed to Mr. Hobbs to effect his enterprise; that the lock should be secured in a certain specified way; and that the key should remain in the possession of Messrs. Bramah, who were to retain the right of using it in the lock when Mr. Hobbs was not at work. Messrs. Bramah subsequently relinquished this last-mentioned privilege, in order that the trial might be perfectly fair; and it was agreed that the key should be sealed up during the whole period, beyond the reach either of Mr. Hobbs or Messrs. Bramah; and that the key-hole should be secured by an iron band, sealed, when Mr. Hobbs was not at work. These and other conditions were embodied in the agreement noticed in the last paragraph.

Mr. Hobbs commenced his labours on July 24th. After a few visits to the lock, Messrs. Bramah wished to have the privilege of inspecting it, or else that such an inspection should be made by the arbitrators; and, during a correspondence which arose out of this request, the operations were suspended. Mr. Hobbs resumed his work on August 16. On the 23d, Messrs. Bramah drew the attention of the arbitrators to the challenge, that the reward of two hundred guineas was offered to the artist who should make an instrument that would pick or open the lock; that he was to be paid the money on the production of the instrument; and that, unless some person were present, it was impossible that any one could know that the lock had been opened by the instrument which might be produced. This letter was not allowed by the arbitrators to affect the arrangements made. We may now consistently give the “Report of the Arbitrators.”

“Whereas for many years past a padlock has been exhibited in the window of Messrs. Bramah’s shop, in Piccadilly, to which was appended a label with these words: ‘The artist who can make an instrument that will pick or open this lock shall receive two hundred guineas the moment it is produced;’ and Mr. Hobbs, of America, having obtained permission of Messrs. Bramah to make trial of his skill in opening the said lock, Messrs. Bramah and Mr. Hobbs severally agreed that George Rennie, Esq., F.R.S., of London; and Professor Cowper, of King’s College, London; and Dr. Black, of Kentucky; should act as arbitrators between the said parties.

“That the trial should be conducted according to the rules laid down by the arbitrators, and the reward of two hundred guineas be decided by them; in fine, that they should see fair play between the parties.

“On July 23 it was agreed that the lock should be enclosed in a block of wood, and screwed to a door, and the screws sealed, the key-hole and the hasp only being accessible to Mr. Hobbs; and, when he was not operating, the key-hole was to be covered with a band of iron and sealed by Mr. Hobbs, that no other person should have access to the key-hole. The key was also sealed up, and was not to be used until Mr. Hobbs had finished his operations. If Mr. Hobbs succeeded in picking or opening the lock, the key was to be tried; and if it locked and unlocked the padlock, it should be considered as a proof that Mr. Hobbs had not injured the lock, but had fairly picked or opened it, and was entitled to the two hundred guineas.

“On the same day, July 23, Messrs. Bramah gave notice to Mr. Hobbs that the lock was ready for his operations.

“On July 24 Mr. Hobbs commenced his operations; and on August 23 Mr. Hobbs exhibited the lock opened to Dr. Black and Professor Cowper (Mr. Rennie being out of town). Dr. Black and Mr. Cowper then called in Mr. Edward Bramah and Mr. Bazalgette, and shewed them the lock opened; they [the last-named two gentlemen are of course meant] then withdrew, and Mr. Hobbs locked and unlocked the padlock in presence of Dr. Black and Mr. Cowper.

“Between July 24 and Aug. 23 Mr. Hobbs’s operations were for a time suspended; so that the number of days occupied by Mr. Hobbs was sixteen, and the number of hours he was actually in the room with the lock was fifty-one.

“On Friday, Aug. 29, Mr. Hobbs again locked and unlocked the padlock in presence of Mr. G. Rennie, Professor Cowper, Dr. Black, Mr. Edward Bramah, Mr. Bazalgette, and Mr. Abrahart.

“On Saturday, Aug. 30, the key was tried, and the padlock was locked and unlocked with the key, by Professor Cowper, Mr. Rennie, and Mr. Gilbertson; thus proving that Mr. Hobbs had fairly picked the lock without injuring it. Mr. Hobbs then formally produced the instruments with which he had opened the lock.

“We are, therefore, unanimously of opinion, that Messrs. Bramah have given Mr. Hobbs a fair opportunity of trying his skill, and that Mr. Hobbs has fairly picked or opened the lock; and we award that Messrs. Bramah and Co. do now pay to Mr. Hobbs the two hundred guineas.

Holland Street, Blackfriars,
Sept. 2, 1851.”

It may be here stated, in reference to the space of time during which the operations were being conducted, that the actual opening of the lock occurred much earlier, so far as concerned the principle involved, though not in a way to meet the terms of the challenge. On his fifth visit, Mr. Hobbs succeeded in adjusting the slides and moving the barrel, preparatory to withdrawing the bolt; but the instrument with which the barrel was to be turned round, being too slight, slipped, and defeated the operation. Mr. Hobbs had then to readjust the barrel, and to make a new instrument to aid him; this new instrument, when completed, enabled him to open the lock in the space of an hour or two.

On the same day Messrs. Bramah addressed a letter to the arbitrators, stating the reasons which induced them to think that, though Mr. Hobbs had succeeded in opening the lock, the manner of doing so did not come within the meaning of the challenge originally made by them. The arbitrators, however, were unanimous in their award, and Messrs. Bramah bowed to it.

In an article written in one of the daily newspapers immediately after the opening of the lock, the following notice was given of the lock and its production: “We were surprised to find that the lock which has made so much noise in the world is a padlock of but 4 inches in width, the body of it 1¹⁄₄ inches thick, and its thickness over the boss 2³⁄₄ inches. Upon opening the outer case of the lock, the actual barrel enclosing the mechanism was found to be 2¹⁄₄ inches in length and 1¹⁄₂ inches in diameter. The small space in which the works were confined, and its snug, compact appearance was matter of astonishment to all present. The lock and key were made forty years since by the present head of the eminent firm of Messrs. Maudslay and Co., Mr. Maudslay being at that time a workman in the employ of Mr. Bramah.”

We may here remark, as indeed has been remarked in former pages, that the Bramah lock is, and will probably continue to be, deservedly celebrated for the amount of mechanism contained in a small space, as adverted to in the last paragraph. The cylindrical form is well calculated for this concentration of power within narrow limits; and the smallness of the key is a great merit.

The objections made by Messrs. Bramah to the award of the committee were embodied in the following letter to Mr. Rennie, dated 9th September:

In order that the opinions of Messrs. Bramah and others may be given with as much fairness as possible, on a matter which they could not feel but otherwise than important to them, we may state, that among the letters to which the picking of the Bramah lock gave rise in the public journals, was the following addressed to the Observer newspaper on 10th October:

Messrs. Bramah are well entitled to offer any explanation concerning the relative perfection of the lock in question, and of one that they could now produce with certain improvements in some parts of the working mechanism; but if these improvements do not involve any new invention, patented or otherwise,—that is, if the lock be really a carrying out of the contrivances already made public,—it is difficult to see why it should not yield to the same treatment as the other. It is true that, shortly after the decision of the arbitrators, Messrs. Bramah exhibited a new lock in their window, and repeated their challenge in the same terms as before, with the single addition, that applications were to be made in writing only. We have reason to know that an application was made, and that the consequence was the withdrawal of the challenge. In respect to the actual contest, however, the character and position of the arbitrators ought surely to hold Mr. Hobbs justified in his proceedings. They were not all Americans (supposing nationality to give a bias in the matter); two were Englishmen, both of distinguished rank in respect to mechanical knowledge; and as Mr. Hobbs was as much bound by their decision as Messrs. Bramah, he was entitled to claim any advantage resulting from a favourable decision.

The following is a description, so far as can be given in words, of the mode in which Mr. Hobbs operated on the Bramah lock. The first point to be attained was to free the sliders from the pressure of the spiral spring; the spring was very powerful, pressing with a force of between 30 and 40 lbs.; and until this was counteracted, the sliders could not be readily moved in their grooves. A thin steel rod, drilled at one end, and having two long projecting teeth, was introduced into the key-hole and pressed against the circular disc between the heads of the sliders; the disc and spring were pressed as far as they would go. In order to retain them in this position, a curved stanchion was screwed into the side of the boards surrounding the lock, and the end brought to press upon the steel rod, a thumb-screw passing through the drilled portion of the instrument and keeping it in its place. The sliders being thus freed from the action of the spring, operations commenced for ascertaining their proper relative positions. A plain steel needle, with a moderately fine point, was used for pushing in the sliders; while another with a small hook at the end, something like a crochet-needle, was used for drawing them back when pushed too far. By gently feeling along the edge of the slider, the notch was found and adjusted, and its exact position was then accurately measured by means of a thin and narrow plate of brass, the measurements being recorded on the brass for future reference. The operator was thus enabled, by this record, to commence each morning’s work at the point where he left off on the previous day. The lock having eighteen sliders, the process of finding the exact position of the notch in each was necessarily slow. Mr. Hobbs employed a small bent instrument to perform the part of the small lever or bit of the key; with this he kept constantly pressing on the cylinder which moved the bolt. He thus knew that if ever he got the slide-notches into the right place, the cylinder would rotate and the lock open. He could feel the varying resistance to which the sliders were subjected by this tendency of the cylinder to rotate; and he adjusted them one by one until the notch came opposite the steel plate. The false notches added, of course, much to his difficulty; for when he had partially rotated the cylinder by means of the false notches, he had to begin again to find out the true ones.

This description accords pretty nearly with that given in a former page; but we reproduce it here to shew not merely what might be the process adopted, but what really has been done. One circumstance ought at least to be noted in these transactions—there is no mystery; the method adopted is the result of a process of reasoning candidly and openly explained.

In justice to Messrs. Bramah we thought it our duty to give them an opportunity of stating what improvements they had made in their locks since the date of the Great Exhibition; and accordingly, on the 28th April, 1853, our publisher addressed to Messrs. Bramah a note, stating that a Rudimentary Treatise on the Construction of Locks was being prepared, and inviting them to contribute thereto. The following is a copy of their reply:

In the Jury Report of the Great Exhibition, Class XXII., are the following remarks: “On the comparative security afforded by the various locks which have come before the jury, they are not prepared to offer an opinion. They would merely express a doubt whether the circumstance that a lock has been picked under conditions which ordinarily could scarcely ever, if at all be obtained, can be assumed as a test of its insecurity.” [page 500]. The conditions here alluded to probably refer to the free access which Messrs. Bramah allowed Mr. Hobbs to have to their lock during a period of thirty days, and we are hence led to infer that the burglar is denied any such facilities. On this point we would refer to the opinion of a high authority. In a paper “on the History and Construction of Latches and Locks,” by Mr. Chubb, read before the Society of Arts, 22d January, 1851, the following graphic passage occurs:

“In order to shew the absolute necessity of secure locks and safe depositories for property, especially in banking establishments, it may not be out of place to trace the systematic care and great sagacity with which the large burglaries are planned. You will bear in mind that an unsuccessful attempt is seldom made where the booty is of any magnitude. The first-rate ‘cracksmen’ always know beforehand where to go, when to go, and what they are going for. When a ‘plant,’ as it is termed, is made upon a house or a bank, precise information is gained, if possible, as to the depository of the valuables; and if it is found that the safeguards are too strong in themselves, and that the locks are invulnerable, the affair is quietly dropped. But if otherwise, then no expenditure of time or misapplied ingenuity is spared to gain the desired end. The house is constantly watched, the habits of its inmates are observed, their ordinary times of going out and coming in are noted; the confidential servants are bribed or cajoled, and induced to leave the premises when their employers are absent, so that impressions may be taken from the locks, and false keys made. When all the keys required are made, one or two men who have not been previously initiated are generally called in, and receive their instructions to be ready at a certain hour on the following day to enter the house. A plan of the premises is put into their hands, they are cautioned to step over a certain creaking stair or plank, and the keys of the different doors are given them. The day or evening is chosen when it is known that the inmates will be from home—the servant, taking advantage of their absence, fulfils a long-standing engagement with his new and liberal friends—a signal is given—the two confederates enter—the so-called safe is swept of its contents, all the doors are carefully re-locked, and not until the bank is opened for business next morning is the robbery discovered.”

In an article in Frazer’s Magazine for November 1852 the following observations were made on the Exhibition Jury Report on Locks: “This jury seems to have consisted of the only persons in England who did not hear of the famous ‘lock controversy’ of last year; for one can hardly imagine that, if they had heard of a matter of so much consequence to the subject they were appointed to investigate, they would have altogether abstained from saying any thing about it. They may be excused for not knowing, because very few people did know, fortunately for our safes and strong boxes, that the mode of picking Bramah’s and Chubb’s locks, by which the transatlantic Hobbs gained so much glory, was suggested and explained in the Encyclopædia Britannica nearly twenty years ago. But it does seem very strange that they, or at least their reporter, should not have known, long before the Report finally left his hands, that Hobbs had picked both of those locks, and taught every lock-picker in England how to do it, if he possesses the requisite tools and fingers. Of course, however, the reporter did not know it, as nobody could read any newspaper last autumn without knowing it. And this jury did exercise their judgment to the extent of declaring that Hobbs’s own lock (under the name of Day and Newell) ‘seems to be impregnable.’ Notwithstanding all which, they express their inability to ‘offer any opinion on the comparative security afforded by the various locks that have come before them.’ The only discrimination which they venture to make is, that the keys of Bramah’s and Chubb’s locks are of convenient size, while Hobbs’s is ponderous and bulky, and his lock complicated; and they might have added (without any very painful amount of investigation), enormously expensive, in consequence of its complication, and probably also more likely, on the same account, to get out of order and stick fast, and so become rather inconveniently impregnable—on the money door of a bank, for instance,—than the other two locks, especially Bramah’s.”

In relation to the opinion just given, it may be remarked that the American lock has shewn no tendencies to get out of order; if well constructed (and good construction is a sine qua non in such mechanism), the parts work into and upon each other with very little friction. In respect to expense, and to the size of the key, a bank-lock is not one in which economy would be much studied, security being the great desideratum. No attempt is made to produce a parautoptic lock of small size or for cheap purposes. The lock, therefore, must be judged of with reference to what it undertakes to perform. And this brings us to notice the attempts made in England to pick the parautoptic or American bank-lock.

The following were the circumstances connected with Mr. Garbutt’s attempt to pick the American lock. It is of course known that a challenge was affixed to the American lock in the Great Exhibition, and it was this challenge which Mr. Garbutt accepted. Mr. Garbutt, it may be here observed, was a working locksmith and engineer; he had been entrusted by Messrs. Fox and Henderson with the care and adjustment of the metal check-tables at the pay-places of the Crystal Palace; he had at a previous period been in the employ of Messrs. Bramah. We mention these facts only on account of an erroneous rumour at the time that he was an agent of Messrs. Bramah in respect to the acceptance of the American challenge; whereas we believe he acted independently, by and for himself.

On Sept. 10th, 1851, Mr. A. H. Renton, Mr. E. H. Thomson, and Mr. W. F. Shattuck,—the first an engineer, and the other two American exhibitors,—were appointed arbitrators to superintend the arrangements, and they met Mr. Garbutt and Mr. Hobbs at the house No. 20 Knightsbridge. The following conditions were agreed to:—That a Newell lock should be selected, and should be screwed to a wooden box; that Mr. Garbutt should have access only to the key-hole of the lock, through which key-hole all his operations for picking the lock should be conducted; that Mr. Garbutt should have uninterrupted and exclusive access to the box, between the hours of nine in the morning and nine in the evening, for thirty days, beginning on the 11th of September, he having during that time the privilege of introducing one associate, and the arbitrators reserving to themselves the right of inspecting the seals placed by them on the box; that, in order to afford every information concerning the internal arrangement of the lock, the trial-lock should be taken to pieces in presence of all the parties; that it should be examined by Mr. Garbutt; that it should be locked and unlocked with the proper key by him and by Mr. Hobbs; that it should be fastened to a box, and the fastenings sealed by the arbitrators; that the key, when the lock was finally locked, should be sealed up by the arbitrators and delivered to Mr. Hobbs, who would retain it until required by the arbitrators to hand it over to them. That at the expiration of the thirty days, or earlier in case either of the success or the abandonment of the attempt, the arbitrators should examine the lock. And, finally, that if Mr. Garbutt should have succeeded in picking the lock (that is, in withdrawing the bolt without injuring the lock), the sum of 200l. should be paid to him by Mr. Hobbs.

In accordance with the above agreement, Mr. Hobbs produced a parautoptic lock, with ten tumblers, marked No. 8560. The key and the lock were examined by Mr. Garbutt. The lock was again put together, affixed to a box, and sealed. Mr. Hobbs set the bits of the key (ten in number) to an arrangement chosen by himself, and the lock was then locked by all parties in succession; the key, after the final locking, being sealed up and returned to Mr. Hobbs. Mr. Hobbs at the same time delivered to Mr. Garbutt a similar but smaller lock, which he was to be allowed to retain during the whole period of the trial, to assist in rendering him familiar with the construction of both locks.

On the 11th of October, the day on which the prescribed period expired, the arbitrators met at the house in question, when Mr. Garbutt delivered up to them the lock uninjured, but unopened. The award of the arbitrators was thereupon given in the following terms: “We therefore hereby certify that Mr. Garbutt having had uninterrupted and exclusive access to the lock during the period of thirty days, and, availing himself of the conditions of the agreement, had every facility for opening the lock that could be obtained without possession of the true key, has delivered up the same into our hands unopened and uninjured; and the said lock has been delivered by us to Mr. Hobbs.”

It will of course be understood that it was one condition of this enterprise, that the particular combination of bits in the key wherewith the lock was finally locked should not be seen by Mr. Garbutt. The key was in the first instance tried by Mr. Garbutt and by the members of the committee, and was found to turn readily in the lock; Mr. Hobbs then left the room, and re-arranged the bits of the key so as to produce a new combination; he then returned to the room, and locked the lock with the key in its altered form; he allowed all present to feel the key turn freely, and then, without allowing any one to see the combination, wrapped the key up in paper, in which it was sealed as above described. Whether Mr. Garbutt, or any one, could have succeeded better by a momentary glance at the arrangement of the key, was not at that moment the question: the terms of the challenge were that he should not see it. What are the circumstances likely to occur if the operator really has access to the key (provided the bits are not very numerous) we may shortly explain.

It is necessary to draw a distinction between picking of a lock and ringing the changes on a permutating key; otherwise some of the late occurrences connected with locks can hardly be understood. After the reading of a paper by Mr. Hobbs before the Society of Arts, a discussion arose, in which it was stated that the Newell lock had been picked in London. Mr. Hobbs deemed it necessary to refute this statement. The report was circulated in many of the London newspapers; and Mr. Jeremiah Smith, the operator in question, supported it by his own statement. Under these circumstances Mr. Hobbs, on April 2, 1852, addressed a letter to the editor of the Observer; of which the following paragraph was intended to point out the distinction above mentioned between “picking” and “ringing the changes:”

“Early last autumn I lent to Mr. Potter, of South Molton Street, one of my locks, for the purpose of giving him an opportunity to make himself acquainted with its principle and construction. After he had had the lock in his possession several weeks, a report reached me that one of Mr. Potter’s workmen had picked my lock. I immediately called on Mr. Potter to ascertain the fact. Mr. Potter informed me that for the purpose of testing the possibility of opening the lock by means of an impression taken, or a copy being made of the true key, Mr. Smith had made a copy of the key by means of a transfer instrument, which instrument he shewed me at the time. After the key was made, it was tried, and found to lock and unlock the lock as readily as the original key. Mr. Potter then sealed the screws of the lock, changed the combination of the key, and locked it. Mr. Smith then took the lock, and with the key that he had made by copying the original, hit the combination, and unlocked it. The lock was of the smallest size, having but six tumblers; the number of changes that could possibly be made were 720. The time occupied by Mr. Smith, according to his own statement, was six hours and fifty-five minutes; this, allowing one minute for each change, would give him time to have made 415 out of the 720 changes before hitting the right one. I asked Mr. Smith why he did not use the original key instead of making a copy? His answer was, that ‘he could change the one he made faster, as he did not have to screw the bits in.’ Any person will readily understand the difference between ringing the combination of a key and picking a lock.”

In other words, the process was this: the operator had the true key, and might have used either this or one which he made from it. This would have sufficed for opening almost any lock ever constructed instantly; but in the American lock he had to find out which of 720 combinations was the right one, and he was employed almost seven hours in doing this. The exploit shewed patience, but had little bearing on the practical subject of lock-picking.

In March 1852 Mr. Smith put forth an offer to accept the challenge made by Mr. Hobbs in respect to the Exhibition lock. Mr. Hobbs agreed to the offer, and chose, as arbitrators on his part, Mr. Hensman, Engineer to the Bank of England, and Mr. Appold, inventor of the centrifugal pump which attracted so much attention at the Great Exhibition. Mr. Hobbs requested Mr. Smith to appoint arbitrators on his side also; but this was not done. Mr. Smith, at a meeting held by the four persons named, expressed a wish that an ordinary commercial lock should be the one experimented on, instead of the more complicated test-lock which had been at the Great Exhibition. This was a departure from the terms of the original challenge; but Mr. Hobbs waived his objection on this point, and offered to substitute a bank-lock with ten tumblers for the Exhibition lock with fifteen, the former being similar in construction but less complex. Another meeting was agreed upon, but Mr. Smith did not attend; and the matter was, by himself, brought to a sudden termination.

To shew the effect of difference in the number of tumblers and key-bits, we may state that, while, at a minute per change, it would take twelve hours to go through all the combinations with a six-bitted key, it would require seven years with a ten-bitted, and 2,500,000 years with a fifteen-bitted key! So much for power of combination, in the arithmetical mode of picking.

We now proceed to notice the violability of sundry minor locks. It might at first appear that the letter-lock is exceedingly difficult to pick; and so it unquestionably is, as long as we merely attend to the chance-medley trials by turning the rings round and round until we happen to hit upon the right combination. But there is another mode of solving the riddle, mechanical rather than arithmetical. A piece of common wire, bent in the form of the shackle, is put in between the ends of the lock; the spring or elasticity of the wire tends to force the ends apart; this causes the pins or studs on the rod to press against the inner edges of the rings. By trying all the rings in succession, some one of them will be found to bind or cling more than the others; this is turned round until the cessation of the bind shews that the notch in the ring has been brought into its right position relatively to the pin on the rod. Then another ring which binds more than the rest is treated in a similar way; until at length all the rings seem to be so far liberated as to indicate that the notches are in the right positions. In the dial-lock, similarly, when a pressure has been brought to bear upon the bolt in the right direction, a trial of the pointers will soon bring the notch in each wheel to the required position.

Some short time after the events in London connected with the lock controversy, Mr. William Brown of Liverpool described the letter-lock noticed in a former page, characterising it as a lock which he believed no one could pick. An incident in the history of this lock was thus narrated in one of the Liverpool newspapers. “Mr. Hobbs was taken by Mr. Milner to the office of Messrs. Brown, Shipley, and Co., and shewn this lock. The safe-door was closed and locked by the cashier at Mr. Brown’s request; and then Mr. Hobbs began to illustrate his views of the construction of the lock by manipulation and explanation, with which the subject of them appeared to sympathise so entirely and promptly that the door opened in a few minutes.”

In respect to the picking of the Egyptian lock, the main difficulty would be in obtaining any false key that would correspond with the pins of the lock; but this might be accomplished in a way analogous to that which is practised in many other cases. If a small piece of wax be laid on a blank key, the key inserted into the lock, and the blank pressed upwards against the pin-holes, there would be left an impression of those holes on the wax; this impression would furnish a guide to the fabrication of a false key. There is also very little difficulty in picking this lock by one of the ordinary instruments.

For the Yale lock, combining something like the pin-action of the Egyptian with the cylinder-action of the Bramah locks, the picking requires the use of an instrument that will fit between two of the pins, and to the outer end of which is attached a lever and weight; by this means a pressure is exerted upon the cylinder in the right direction for it to turn, and the pins are made to bind. Then, with another instrument, the pins are felt, and each one moved until it seems to be relieved from the bind: this indicates that the joint in the pin coincides with the joint between the two cylinders; and when all have been similarly treated, the weight acting on the inner cylinder will turn it. It is evident that this method is the same in principle as the one applicable to the Bramah lock.

CHAPTER X.
EFFECTS OF THE GREAT EXHIBITION OF 1851 IN IMPROVING ENGLISH LOCKS.

We have now to refer to the effects of the lock controversy. It was no doubt annoying to be told, on good authority, that the machines on which we so much prided ourselves were wrong in principle; and that our locks, in order to afford the degree of security which are expected of such contrivances, must be re-constructed. The grumbling with which the first part of this proposition was received would alone have sufficed to lead to a suspicion of its truth, if the large number of new locks that have actually appeared had not confirmed it. Whether the second part of the proposition has been fairly carried out, is a point which must now be considered.

One of the first locks produced during or immediately after the lock controversy was Mr. Parnell’s, to which the bold term of patent defiance lock is attached. This lock is said to depend for its security on a mode of arrangement which may best be described in the inventor’s own words: “Viewing the lock from its exterior, it presents nothing remarkable; but, upon removing the plate, it will be seen that all possible access to the mechanism with false or surreptitious keys is effectually prevented by a solid cylinder of hardened [?] brass, with protecting wards extending the whole depth of the lock, and having in the centre the aperture for the key, which fits to a mathematical nicety so exact as to preclude the possibility of any second instrument being used to open it.... This protecting cylinder must revolve with the key to get to the works; and the moment it passes from the key-hole in going round to lock or unlock, the solid portion moves into its place, and so completely closes that aperture that the point of a pin, or a fine steel-pen, has failed to be inserted between it and the outer plate or cap, to say nothing of the utter hopelessness of perforating the metal.

“The cylinder or protecting cap, though it revolves by the action of the key somewhat in the same way as the cylinder of the Bramah lock, appears to be intended rather for closing or protecting the key-hole than for governing the movements of the bolt. The internal arrangements of the lock are as follow: Supposing the bolt to be shot, and to be about to be unlocked, the key, by the time it has made about one-third of a rotation, meets with a forcible resistance in the shape of an upright spring-bolt or detector of strong steel acting on the revolving cylinder. The key passes this detector, and arrives at the levers or tumblers. In the bolt-stud which works in the slot of these tumblers there is a small deep serrated notch on one side, corresponding to similar notches on each of the tumblers; if, therefore, the bolt be forced, these notches would lock into each other in a similar manner to the catch on a ship’s windlass or a hoisting crane. There is also a double-action tumbler-bolt, so adjusted, that if any of the tumblers be overlifted, this little appendage becomes thrust down at one end into the bolt of the lock, where it wedges all fast until the tumblers become properly re-adjusted. The double-action tumbler-bolt also falls into the lock-bolt when the latter is locked or shut, thereby imparting an additional strength to the lock. The key has a power of expansion or enlargement while turning in the lock; it meets with an eccentric plate which draws out the bits somewhat; so that, at the moment of acting on the tumblers, they protrude farther from the pipe of the key than when the key entered the key-hole. The key is, in fact, larger when in than when out of the lock. There is connected with the works of the lock a ‘detention-cap,’ so formed that, in the event of a false key being used, a powerful bolt instantly locks into the revolving cylinder, and holds fast the surreptitious instrument.” Such is, in substance, the account which Mr. Parnell has given of his own lock. It must, however, be stated, that the points of security or novelty claimed by Mr. Parnell for his lock were patented by previous inventors. The revolving cylinder or curtain was claimed by Mitchell and Lawton in the patent of 7th March, 1815, as noticed at page 52 ante. The expanding key-bit was claimed by Mr. Machin of Wolverhampton in 1827, as noticed at page 61, and by Mr. Mackinnon (page 62); while the serrated notches in the tumbler were used by many lock-makers long before the date of Mr. Parnell’s patent. The detention-cap for catching and holding a false key when put into the lock was also patented by Mitchell and Lawton, as noticed at page 53 ante.

We come now to notice a lock lately invented by Mr. E. B. Denison (the author of the Rudimentary Treatise on Clocks in this series), which has the merit of combining considerable novelty in construction with security. After the details given in the two preceding chapters, it will certainly be no small praise when we express our conviction that in the present state of the art of lock-picking, this lock may be considered as secure. Mr. Denison has furnished us with a description of his lock, which we insert almost in his own words. Mr. Denison claims for this lock the following advantages:—

1. That a very large and strong lock on this construction only requires a very small key. 2. That no key is required to lock it, although it is free from the inconvenience pertaining to spring-locks, viz. that the door cannot be shut without locking itself. Moreover this lock is more secure than any spring-lock can be. 3. That it cannot get out of order from the usual causes of the tumblers sticking together or their springs breaking, inasmuch as the action of the tumblers does not depend on any thing but the key and the handle, and there are no tumbler-springs. 4. That for the same reason, the parts of this lock do not require any polishing or delicacy of execution. 5. That the key-hole being completely closed by a curtain, except when the key is in, the lock is protected from the effects of the atmosphere and dust entering at the key-hole. 6. That this lock is secure against any known mode of picking; the smallness of the key-hole prevents the insertion of any instrument strong enough to open the lock by violence. 7. That this lock, from the simplicity of its construction, admits of being made at small cost.

These objects are accomplished as follows:—In the large-sized locks, such as would be used for safes and large doors, the tumblers T, fig. 51, are made of pieces of hoop-iron, 6 or 7 inches long and 1¹⁄₂ inch wide: these tumblers are supported by and turn on a pin a, placed at about the middle of their length; so that being balanced on the pin, or nearly so, and having their separating plates P between them, which cannot turn, the tumblers will stand in any position indifferently; and in order to secure sufficient friction to keep them steady, one or more of the separating plates P is bent a little, so as to act as a spring when the cap of the lock is screwed down. The lock is shewn in fig. 51 as locked, the bolt B having been shot by the fantailed piece f on the handle, and the tumblers sent down, so that the stump s cannot enter their jaws by the other piece of the handle; and it is evident that the handle cannot draw the bolt back again until the tumblers have all been raised by the key to the proper position to allow the stump s to enter their jaws. It will be observed that in the position shewn in the figure, the stump does not touch the tumblers; and consequently, so long as the bolt is kept in the position represented, no pressure of the stump against the tumblers can be felt, although by means of a false key or pick-lock the tumblers be raised to any height. No implement, however, can be pushed into the key-hole without first pressing in the curtain K, which is held up against the cap of the lock by the two spiral springs c c on each side of the key-hole; and at the back of the curtain there is a square plug p, which goes through a hole in the back of the lock, and has a notch in it through which the bolt can pass when the curtain is up, closing the key-hole, but at no other time. In other words, the act of pushing in the key sends down the curtain plug, the effect of which is to hold the bolt fast in the position in which the stump cannot be made to touch the tumblers. If the proper key be used and turned about half round to the right, it will bring the tumblers to the proper height for the stump to pass. The key is then taken out; for so long as it is in the lock, the bolt cannot be moved; and then turning the handle to the right, the bolt is drawn and the door opened.