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]
[5] “But is there not this danger, that at the same time we shall be
giving lessons to the thieves? It is not very probable that they will
seek instruction of us, or that they have any need of it; they are
greater masters in the art of opening doors than we can pretend to be.
Let us then learn the art of opening locked doors, in order that we
may acquire that of securing them in such a way as to leave little or
nothing to be feared on account of their security.”
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.”
[6] See also Mr. Owen’s suggestion, p. 59, _ante_.
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.