WARDED LOCKS, WITH THEIR VARIED APPENDAGES.
The more ordinary locks are of an oblong quadrangular shape. In nearly
all of them, either a bolt shoots out from the lock, to catch into some
kind of staple or box, or a staple enters a hole in the edge of the
lock, and is there acted upon by the bolt. A common room-door lock will
illustrate the first of these kinds, a tea-caddy lock the second. The
key, as is well known, enters a receptacle made for it; and the shaft of
the key generally serves as a pivot or axis around which the web or flat
part of the key may move in a circular course. During this movement the
web acts directly or indirectly on the bolt, driving it in or out
according to the direction in which the key is turned; the key impels
the bolt one way, certain springs act upon it in another, and the
balance between these two forces determines the locking and unlocking of
the bolt. _Wards_, or _wheels_, are contrivances for rendering the
opening difficult without the proper key; and it is of warded locks that
we shall chiefly treat in this chapter.
[Illustration: fig. 6. Interior of a back-spring warded lock.]
The annexed cut, fig. 6, represents the interior of an ordinary
back-spring lock, without tumblers. Such a lock may usually be known
from a tumbler-lock by this simple circumstance, that it emits a smart
snapping noise during the process of locking, occasioned by the pressure
of the spring when the bolt is in a particular position. In the woodcut
the bolt is represented half out, or half shot. At _a a_ are two notches
on the under side of the bolt connected by a curved part; _b_ is the
back spring, which becomes compressed by the passage of the curve
through a limited aperture in the rim _c c_ of the lock. When the bolt
is wholly withdrawn, one of the notches _a_ rests upon the rim _c c_;
and the force with which the notch falls into this position, urged by
the spring _b_, gives rise to the snapping or clicking noise. When the
bolt is wholly shot, the other notch rests in like manner upon the edge
of the aperture in the rim.
It must be obvious at a glance, that this back-spring lock is
objectionable on the score of security, on account of the facility with
which the bolt may be forced back by any pressure applied to its end, a
pressure which may often easily be brought to bear. At the centre of the
lock is seen the end of the key acting on a notch in the bolt, and
surrounded by wards.
[Illustration: fig. 7. Section to shew the action of wards.]
It is not at a first glance that the relation between the clefts in a
key and the wards of a lock can be duly appreciated; because the wards
present themselves to view as portions of circles to which nothing in
the key seems to correspond; but if it be borne in mind that the key has
a rotary motion within the key-hole around the pipe or barrel as an
axis, the circular form of the wards will be accounted for, and their
_section_ will be regarded as exhibiting the looked-for relation to the
wards of the key. In the annexed cut, for example (fig. 7), which
represents a portion of the interior of a warded lock, the curved pieces
of metal are the wards (two in this case); and there are two clefts in
the bitt of the key to enable the latter to take its circular course
without interruption from the wards. If the clefts were other than they
are, either in number, position, or size, this freedom of the key’s
movement could not be obtained.
[Illustration: fig. 8. End sections of keys.]
When once the opinion became established that a lock is rendered secure
by virtue of its wards, (a theory which we shall have to discuss in a
later page,) much ingenuity was displayed in varying the wards of the
lock, the clefts of the key, and the shape of the keyhole. Even if the
two former were unchanged, a change in the latter might add to the
puzzlement of the arrangement. For instance, in the annexed cut (fig.
8), all the six keys represented may have clefts or cuts exactly alike,
all alike adapted to the wards of one particular lock; yet the
differences in the _thickness_ of the web are such, that if the keyholes
were shaped in conformity therewith, each keyhole would be entered by
one of these keys; _b_ and _c_ differing from _a_ in the relative
thickness at different points, and _d_, _e_, and _f_ having certain
curvatures and cavities not to be found in the other three.
[Illustration: fig. 9. Examples to shew the action of “master,” or
“skeleton keys.”]
But without waiting for the detailed examination of the relative
security and insecurity of locks, we may at once shew how simple is the
principle which renders the warded system fallacious. In fig. 9 we
shall be able to illustrate this. Numbers 1, 2, and 3, all appear very
different keys, and it is quite true that neither one would open a lock
adapted for either of the other two; and yet the very simple arrangement
No. 4 would open all three. This No. 4 is called a _skeleton-key_; and
the relation which it bears to the others may be expressed in the form
of a proposition thus: at any point where there is solid metal in _all_
the keys, there must (or may) be solid metal in the corresponding part
of the skeleton-key; but at any point where there is a vacancy or cavity
in _any_ of the keys, there must be a cavity in the corresponding part
of the skeleton-key. If Nos. 1, 2, 3, 4, be examined, this proposition
will be found to be borne out; there is so much cavity in No. 4 that it
avoids the wards in all the three locks, nothing being required but the
tongue of metal to move the bolt. Sometimes, to add to the safety, wards
are attached to the front as well as the back plate of the lock; and
then there may be a double series of notches required in the key, such
as in No. 5; but if this be compared with Nos. 9, 10, 11, it will be
found that although no one of the four would open a lock adapted for
either of the other three, yet the skeleton-key No. 12 would master them
all, having cavities wherever any of the others have cavities. This is
the theory of the _master-key_, by which one key may be made to command
many locks. Nos. 6 and 7 have complicated wards; but the key is so much
cut up as to be weakened more than is desirable. No. 8 enables us to
point out the difference between two distinct classes of keys. Keys with
pipes or barrels fitting on a pin or pipe-shaft can only open a lock on
one side of the door or box; but a key with a solid stem, as No. 8, has
the clefts so cut as to open the lock from either side, as in a
street-door lock: it is, in fact, two warded keys fixed end to end, only
half of which is employed at one time in opening the lock.
[Illustration: fig. 10. Wards of an old French lock.]
Some of the warded locks of the last century are curious. While the idea
prevailed that a complicated ward gave security, there was room for the
exercise of ingenuity in varying the shape of the wards. Fig. 10 is
copied from the great French work. It represents the cuts in the key,
and also (seen perspectively) the complicated forms of the pieces of
metal which constitute the wards corresponding with those cuts. The
aperture in the key at 16 fits upon the metal surrounding the keyhole at
18; and the M-shaped cuts at 17 fit in like manner upon the
similarly-shaped metal pieces at 19.
Another example of a similar kind is shewn in fig. 11, where an anchor
appears to have been the favourite form. The anchor cuts in the key are
shewn at 26; while in the wards the bottom of the anchor is near the
keyhole at 28, and the top at 29.
[Illustration: fig. 11. Wards of an old French lock.]
[Illustration: fig. 12. Wards of an old French lock.]
A similar illustration occurs in fig. 12, where the star-like cuts at 34
on the key correspond with the star-like wards at 33.
[Illustration: fig. 13. Exterior of an old secret lock.]
[Illustration: fig. 14. The same, with a portion of the front let down,
shewing the key-hole.]
From the fifteenth to the eighteenth centuries locks were made in
France, on which a vast amount of care and expense was bestowed. They
were, in an especial degree, decorative appendages as well as
fastenings. They were of three kinds: room-locks, buffet-locks, and
chest-locks; they were fixed on the outside of the door or lid, so as to
be fully visible. The key had a multitude of perforations which bore no
particular relation to the wards of the lock, but which were regarded as
tests of the workman’s skill. The honorary distinctions awarded to
apprentices and aspirants in the art depended very much on the number
and fine execution of these perforated keys. The locks, considered as
fastenings, had slender merit; although usually throwing four bolts,
they were not very secure. Fig. 13 represents the exterior of a lock
made about the year 1730, by Bridou, a celebrated Parisian locksmith. It
was a lock belonging to a coffer or strong chest; all the works being
sunk below the level of a carved architectural moulding or ornament.
There is a secret opening near the part C, forming a portion of the
ornamental design; it allows a bolt, shewn at D, fig. 14, acted on by
the spring E, to be touched, by which a doorway opens upon the hinges at
B B. A A are a sort of pilasters, which aid in forming a hold for the
bolts. The little ornament at C is drawn down by the hand, opening the
secret door and revealing the key-hole G. S S, O O, Z Z, are ornaments
fastened on at _b c d_, fig. 14, by nuts and screws, intended to display
the skill of the workman. The lock itself, access to the keyhole of
which is obtained within the secret door, has nothing very remarkable
about it.
[Illustration: fig. 15. Examples of true and false keys.]
Mr. Chubb, in his paper read before the Institute of Civil Engineers,
illustrated the insecurity of the warded lock by the example of one
which had actually been placed in the strong-room of a banking house,
and which is represented in the annexed cut (fig. 15). The wards are
here shewn, surrounding the central key-pin; and from the appearance of
the key, shewn at _a_, it is evident that these wards must have been
rather complex. But the uselessness of the wards was proved by the
result. A burglar employed an instrument, shaped like that at _b_,
having on one of its faces, or sides, a layer of wax and yellow soap;
this instrument, being introduced through the keyhole and turned a
little way round, brought the soft composition in contact with the ends
of the wards, and these ends thus left their impress on the composition.
A false key was then made, as at _c_, which, however clumsy it may
appear, has a cavity, or vacuity, where there is a cavity in the true
key; and by such a surreptitious instrument was the lock opened. Even so
rude an instrument as _d_, by passing round the wards, might open such a
lock.
We are somewhat anticipating the full consideration of this subject;
but it is desirable at once to explain how and why an improvement on the
warded lock was sought for.
In connexion with the fanciful eighteenth-century locks, lately adverted
to, we may remark, that no less a man than Louis XVI. was an amateur
workman in this department of mechanical art--or at least in smith’s
work, which in France is generally considered to include lock-making.
Sir Archibald Alison says, in his _History of Europe_:--“He had an
extraordinary fondness for athletic occupation and mechanical labour;
insomuch that he frequently worked several hours a-day with a blacksmith
of the name of Gamin, who taught him the art of wielding the hammer and
managing the forge. He took the greatest interest in this occupation,
and loaded his preceptor in the art with kindness; who returned it by
betraying to the Convention a secret iron recess which they had together
worked out in the walls of the cabinet in the Tuileries, wherein to
deposit his secret papers during the storms of the Revolution.” There
are not wanting indications that the unfortunate monarch wrought upon
locks, as well as upon safes and strong-rooms.
Besides wards, there have been numerous other contrivances for adding to
the security of locks--including screws, escutcheons, spiral springs,
wheel-and-pinion work, alarums, and multiple bolts. As these are not of
sufficient importance to be treated in separate chapters, we shall here
give just so much notice of them as will illustrate their general
character. Some of them are found combined with the “tumbler” principle,
presently to be described; but all of them, it is now well known, were
employed in various, ways when the tumbler lock was but little
understood, and when the warded lock was held in esteem.
The Marquis of Worcester, whose curious _Century of Inventions_, written
nearly two hundred years ago, contains so many suggestions which
ingenuity has since developed into practical completeness, gives four of
his inventions in the following words:--
69. “A way how a little triangle screwed key, not weighing a shilling,
shall be capable and strong enough to bolt and unbolt, round about a
great chest, an hundred bolts, through fifty staples, two in each, with
a direct contrary motion; and as many more from both sides and ends;
and, at the self-same time, shall fasten it to the place beyond a man’s
natural strength to take it away; and in one and the same turn both
locketh and openeth it.
70. “A key with a rose-turning pipe and two roses pierced through
endwise the bit thereof, with several handsomely contrived wards, which
may likewise do the same effects.
71. “A key, perfectly square, with a screw turning within it, and more
conceited than any of the rest, and no heavier than the triangle screwed
key, and doth the same effects.
72. “An escutcheon, to be placed before any of these locks, with these
properties: First, the owner, though a woman, may with her delicate hand
vary the ways of causing to open the lock ten millions of times beyond
the knowledge of the smith that made it, or of me that invented it.
Second, if a stranger open it, it setteth an alarum a-going, which the
stranger cannot stop from running out; and besides, though none shall be
within hearing, yet it catcheth his hand as a trap doth a fox; and
though far from maiming him, yet it leaveth such a mark behind it as
will discover him if suspected; the escutcheon or lock plainly shewing
what money he hath taken out of the box to a farthing, and how many
times opened since the owner had been at it.”
Mr. Partington, in his edition of the marquis’s singular work, makes a
few comments on these lock-and-key contrivances. He says that the lock
is evidently intended to operate on the principle of applying a _screw_
for the purpose of moving the bolt, instead of using a key as a lever
for this purpose. That such a plan might be applied to locks generally,
he observes, there can be no doubt; and by a similar contrivance the
large keys at present in use for outer doors, iron chests, &c. might be
advantageously reduced by this means. By employing the escutcheon
mentioned by the marquis, much additional security would be obtained. It
must be confessed, however, that many of the marquis’s statements are
difficult to credit.
The escutcheon has been a favourite resource with lock-makers. Mr.
Mordan’s escutcheon, for instance, introduced before the Society of Arts
in 1830, is a contrivance to be placed temporarily over the keyhole of a
door, to prevent the picking of the lock during the owner’s absence. The
escutcheon, or “protector,” has a short pipe which, after the door has
been locked, is thrust into the keyhole; attached to the pipe is a small
lock, on Bramah’s or any other convenient principle, so contrived that,
on turning its key, two lancet-shaped pieces fly out laterally and bury
themselves in the wood. The escutcheon cannot be removed until the small
key has reacted upon the small lock; and until this removal has taken
place, the large key cannot reach the keyhole.
A curious application of the escutcheon principle attracted some
attention among locksmiths about seventy years ago. One of the first
premiums awarded by the Society of Arts, after the commencement of their
“Transactions,” was to Mr. Marshall, for a “secret escutcheon,” in 1784.
In his description of his new invention, he adverts to the marquis of
Worcester’s wonderful escutcheon, and to the many attempts which have
since been made to produce an apparatus which should realise the
marquis’s description. He supposes that the letter padlock originated as
one among many varieties of these imitative inventions; but this may be
doubted. Mr. Marshall’s contrivance, however, was in effect an endeavour
to improve upon the letter-lock. He considered it an objection that, in
ordinary locks of this kind, the letter-rings admit of no variation of
place; and he sought to remedy this defect. It is not so much a new
lock, as an escutcheon for a lock, which he produced. There is a studded
bar passing through a barrel; there are five rings which work
concentrically on this barrel; there are letters on the outer surfaces
of the rings, and notches on the inner surface; but when, by the usual
puzzle-action of the rings, the notches in them have been brought into a
right line with the studs of the bar, the result is, not that the hasp
of a padlock is raised, but that the escutcheon is removed from the
keyhole of an ordinary lock. Mr. Marshall’s contrivance, therefore, is
not so much a ring padlock, as a puzzle-ring security for the escutcheon
of a fixed lock.
Some locks work by a screw and a spiral spring, instead of an ordinary
key. Mr. W. Russell received a silver medal from the Society of Arts,
about thirty years ago, for a new mode of locking the cocks of
liquor-casks. Under ordinary circumstances, as is well known, the cock
of a barrel or cask is in no way secure from the action of any one who
can approach near enough to touch it; and different methods have been
adopted of obtaining this security or secrecy. One plan is to employ a
perforated cap, soft-soldered to the barrel of the cock, immediately
over the grooved plug, the top of which plug is formed to the shape of
the perforation, and a socket-key of the same form is introduced to turn
the plug or open the lock. Another plan is to employ an iron saddle or
staple, passing over the plug and below the bottom of the cock, through
which a bolt is put, and a pendent padlock attached. The first method is
very inefficient; the second is much superior, and has been largely
adopted for locking the cocks of coppers, stills, vats, and other large
vessels. But Mr. Russell thought some further improvement wanted. He
caused a hole to be bored through the barrel, and to some depth into the
plug when the latter is in the position for closing the cock. A stud
works into this hole in such a way, that when the stud is driven home,
the plug cannot be turned or the lock opened. The stud is attached at
its other end to a spiral spring connected with a screw; a key is
employed, the hollow pipe of which has an internal screw; and when this
key is inserted in the cock-barrel and turned twice round, it draws back
the stud, and allows the plug to be turned round in the proper way for
opening the cock.
It is not often that wheel-and-pinion work is introduced into locks; the
delicacy, the costliness, the weakness, and the tendency to get out of
order, would all militate against the frequent adoption of such a
course. It is, however, adopted occasionally. Mr. Friend’s secret-lock,
introduced to the notice of the Society of Arts in 1825, had a train of
wheels which acted upon the bolt, driving it out whenever the circular
arcs of three wheels moved against it, but allowing a spring to force it
back again whenever a deep cleft in each of the wheels locked into a
stud on the bolt. There were certain numbers on a guide-plate, and a
power of combining these numbers in great variety; and a provision that
the bolt could be unlocked only by the same combination of numbers which
had locked it. The guide-plate was a separate piece of apparatus,
carried in the pocket of the user as a companion to the key. The key was
of no use without the guide-plate, nor the guide-plate without the key.
The user ‘set’ the numbers on the guide-plate, then applied it to the
face of the lock, then introduced the key into the key-hole, and turned
the key partially round; the bolt was now shot, and the guide-plate
removed. If the key were used without the guide-plate, the bolt might be
locked, but it was always unlocked again by the time the key had made a
complete circuit. There was considerable ingenuity in the idea of this
lock; but we believe it never went further than a model. Indeed many of
the locks elaborately described in books have never had an existence as
acting working locks.
A very ingenious principle has been occasionally introduced, in which
clock-work regulates the interval of time which must elapse before a
lock can be opened, even with its proper key. The object is, to ensure
the safety of the lock during a journey, or until a particular person be
present, or until the locked article is conveyed to a particular room. A
patent was taken out in 1831 for a lock on this principle by Mr.
Rutherford, a bank agent at Jedburgh. Against the end of the bolt of the
lock is placed a circular stop-plate, so adjusted that the bolt cannot
be withdrawn until a particular notch in the rim of the circular plate
is opposite the end of the bolt. The plate is put in rotation by
clock-work. As the notch can be set at pleasure to any required distance
from the end of the bolt, the lock may be secured against being opened,
either by its own or any other key, until any assigned number of minutes
or hours after it has been locked; for the plate may be made to revolve
either slowly or quickly, by varying the number of wheels in the
clockwork. When the lock is used for boxes or portable packages, the
clockwork must be moved and regulated by a spring; but when it is
applied to closets or safes, a descending weight and a pendulum may be
employed. It is manifest that this system is susceptible of being
greatly varied in its mode of application; and it has many points of
interest about it. That a man cannot open his own lock with his own
proper key, until the lock gives permission by assuming a particular
state or condition, certainly strikes one as being susceptible of many
useful applications, where _time_ is an element taken into the account.
A curious alarum-lock was invented by Mr. Meighan, in 1836, in which the
bell or alarum is not placed behind a door, as in many alarum
contrivances, but within the lock itself. Two or more studs are placed
on the bolt, which press against the lower end of a small tumbler; the
movement of the tumbler elevates a hammer; but as soon as the point of
the tumbler becomes released from the stud, a spring presses the hammer
down forcibly, and causes it to strike against a small bell placed near
it. This sounding of the bell will be repeated, during the shutting of
the bolt, as many times as there are studs to act upon the point of the
tumbler.
Much of the ingenuity which has been displayed in locks depends on the
employment of multiple bolts, there being all the additional strength
which results from the use of two or more bolts instead of simply one.
Ordinary doors seldom afford us examples of these double bolts; but they
may be frequently seen in cabinets and desks, where two staples fixed
to the lid fall into two holes in the lock, and are retained by two
bolts. The most remarkable and complicated varieties, however, are those
in which the bolts, instead of shooting parallel and nearly together,
shoot in wholly different ways; one up, one down, one to the right, one
to the left, and so on. It is on safes, strong boxes, and the doors of
strong rooms containing valuable treasures, that such locks are usually
placed. The mechanism is such that the key acts upon all the bolts at
once, through the intervention of levers and springs of various kinds.
[Illustration: fig. 16. Multiple bolts of an old chest-lock.]
The above woodcut represents a very curious specimen of these
multiple-bolt locks. It is copied from the great French work; and the
ponderous chest to which it is attached is, we are told by Réaumur,
“known at Paris by the name of the strong German coffer.” He further
says, “nothing is wanting in these coffers on the score of solidity.
They are made entirely of iron; or if of wood, they are banded both
within and without with iron; and can only be broken open by very great
violence. Their locks are almost as large as the top of the coffer, and
close with a great number of bolts. The one which we have engraved has
twelve fastenings; they have been made with twenty-four, or more.” His
next remark on the subject is a sensible one: “Notwithstanding the large
size of these locks, and all the apparatus with which they are provided,
they correspond but ill with the solidity of the rest of the coffer. If
we have given a representation of one, it is chiefly to shew how little
confidence one could have in such a lock, and what are its defects, in
order that we may avoid them.” It is not difficult, by tracing the
action of the several levers, to see how one movement of the key, in the
centre of the lid, would act upon all the bolts. In the engraving (fig.
16) _a_, _f_, _h_, _c_, are the four corner bolts; six others, _a d e_,
_a d e_, are on the long sides, three on each; and two, _b g_, on the
short sides. Every bolt is provided with a spring, of which three or
four are shewn at Z Z Z. There is no staple or box to receive each bolt;
but all shoot or snap beneath the raised edge E running round the top of
the box just within the exterior at A A. The keyhole in the front of the
box at D is a deception or mask; the real keyhole is in the middle of
the lid concealed by a secret door opened by a spring. When the key has
moved the great central bolt, this acts upon the other bolts P Q R S T,
&c.; V V are studs which act upon two of the bolts; Y Y are staples
confining the great bolt; _k_, _l_, _c_, _p_, _x_, are small levers
which transmit the action to the corner bolts; _q_, _r_, _s_, _t_, _n_,
are the small levers which render a similar service to the side and end
bolts; L L within the chest, and M M on the lid, are contrivances for
limiting the movement of the latter; C H, H C are iron straps or bands
by which the interior of the chest is strengthened. After all, this is
not so much a lock as a series of spring latches.
If a lock can be picked, the picking is as effective whether the lock
has one bolt or twelve bolts. This fact led Mr. Duce, in 1824, to
construct, instead of a four-bolt lock, four distinct one-bolt locks,
fixed in the same frame and opened by the same key; the bolts to be
moved in succession instead of simultaneously. It would require four
times as long to pick this as a four-bolt lock of similar action.
There have been many other varieties of the multiple bolt, but we need
not stop to describe them.