868 L O 
LOCKVIT'ZE, a town of Ruffa, in the government 
of Tchernigov, on the Sofa : ninety-fix mites fouth-eaft 
of Tchernigov. Lat. 50. 20, N. Ion. 2.8. 14. E. 
LOCHWIN'NOCH, a town of Scotland, in the county 
of Renfrew ; confiderable for its cotton manufactures : fix 
miles fouth-vveft of Paifley. 
LOCK, f. [toe, Sax.] An inftrument compofed of 
fprings and holts, ofed to fallen doors or chefts.—As 
there are lochs for feveral purpofes, fo are there feveral 
inventions in locks, in contriving their wards -or guards, 
Moxon. 
We’ve locks, to {lifeguard necelfaries, 
And pretty traps to catch the petty thieves. Shakefpeare. 
The lock is reckoned the mafterpiece in fmithery; a 
great deal of art and delicacy being required in contriving 
and varying the wards, fprings, bolts, See. and adjufting 
them to the places where they are to be ufed, and to the 
various occafions of uling them. 
From the various ftruCture of locks, accommodated to 
their different intentions, they acquire various names. 
Thofe placed on outer doors are called Jlock-locks ; thofs 
on chamber doors, Jpring-locks ; thofe on trunks, trunk- 
locks, pad-locks, See. 
As on the proper confiruCtion of locks the fecurity of 
the mod valuable kinds of property almoft entirely de¬ 
pends, and as numberlefs devices are continually fallen 
upon to elude the utmoft efforts of mechanical invention 
in this rei'peCt, it thence becomes an objeCt of no fmall 
importance to invent a lock which it fltould be impoflible 
to open except by its proper key. 
A common lock confilts of a ftrong holt, which mud be 
fitted in a proper box or cafe affixed to the door, and in- 
clofing it on all fides, to defend it from violence, that it 
cannot be withdrawn except by the application of the 
key, which fliould enter the lock by a fmall key-hole, 
and be furrounded by numerous wards, that occafion the 
paffage the key paffes through, in turning round to move 
the bolt, to be very crooked and intricate, and thus pre¬ 
venting the introduction of any inltrument or falfe key to 
withdraw the bolt. The third part of the lock is the 
tumbler, which is a catch or click holding the bolt from 
being withdrawn except the tumbler be fir ft removed by 
the key, .which is done at the fame time it flioots the bolt. 
This common lock cannot be made perfectly fecure from 
being picked or opened without the right key, from the 
circumftance that the wards, though they may be vari- 
oufly difpofed, fo as to require a very crooked key, mull: 
be always left fixed in the lock, and their figure may be 
taken by introducing a fmall falfe key, covered with wax 
or other plaftic fubllance, and receiving the impreffion of 
the wards, from which information a falfe or lkeleton key 
may be made, that will enter the lock and withdraw the 
bolt; or, if it will only raife up the tumbler, the bolt may 
fometimes be forced back by other means. Another rea- 
fon of the infufficiency of the common lock is, that the 
variations capable of being made in the arrangement of 
the wards are not fufficient to produce the required num¬ 
ber of locks without having great numbers exactly alike, 
and their keys capable of opening each other reciprocally; 
from which circumftance they become but an imperfeCl 
fecurity, as any ill-difpoled perfon may, by furnifh- 
ing himfelf with a great variety of old keys, be ena¬ 
bled to open almoft any common lock ; particularly if 
thefe keys are filed away to fkeletons, that is, leaving as 
little as poflible of the folid part of the key, which will 
then have a greater chance of paffing in between the in¬ 
tricate wards. 
To produce a lock which would be free from thefe ob¬ 
jections has been the ftudy of many ingenious mechanics, 
whofe various locks have different properties and advan¬ 
tages. The locks invented by Mr. Jofeph Bramah difplay 
great ingenuity, and demand a particular defeription, hav¬ 
ing been in very general ufe for many years pad, and 
greatly admired, lie obtained a patent for his invention 
C K. 
in 1784, and eftahliftied a manufactory of them, In which 
he employed a number of ingenious tools and engines for 
the fabrication of the different parts. Mr. Bramah lias 
indeed written a treatife upon the fubjeci; from which we 
{hall make a few extracts, introductory to the explanation 
of his patent locks. 
The firft perfon, according to this ingenious mechanic;, 
who had any claim to merit in the branch of lock-making, 
is Mr. Baron ; whofe lock he acknowledges to be by far 
more perfeft and fecure than any that ever appeared be¬ 
fore ; though he ftill confiders it as unfit for giving that 
abfolute fecurity which is to be wifhed for. His improve¬ 
ment confifted in the proper application of what are called 
tumblers. “ Thefe (fays Mr. -Bramah) are a kind of grap¬ 
ple; by which the bolt is confined, as well in its aCtive as 
in its pafiive ftation, and rendered immovable till fet at li¬ 
berty by the key. One of thefe inftruments is commonly 
introduced into all locks that are of any ufe or value; it is 
lodged behind the bolt, and is governed by a fpring which 
aCts upon the tumbler as the tumbler aCts upon the bolt: 
the application therefore of any force to tue tumbler, 
which is fuperior to the force of the fpring, will caufe it 
to quit its hold, and fet the bolt at liberty.” In the com¬ 
mon method of applying thefe machines, however, it mat¬ 
ters nothing how far the tumbler is lifted above the point 
at which it ceafes to controul the bolt; but it is otherwife 
in thofe of Mr. Baron's confiruCtion. The aCtion of his 
tumblers is circumfcribed by a certain fpace cut in the 
centre of the bolt, of dimensions fufficient only to anfwer 
the purpofe intended. The fpace in which the tumbler 
moves is an oblong fquare; and is not only furniflied with 
niches on the under fide, into which the hooks of the 
tumblers are forced by the fpring as in other locks, but is 
provided with correfpondent niches on the other fide, into 
which the hooks are driven if any greater force be applied 
to the tumblers than what is juft fufficient to difc .gage 
them from the bolt. Hence it becomes abfolutely necef- 
fary, in the making of a falfe key, to conltruCt it in fuch 
a manner, that it may with the greateit exaCtnefs give the 
requifite degree of preffure, and no more. 
Mr. Bramah allows that this is a very great improve¬ 
ment; but objeCts that it is ftill poflible to frame a key 
which will open it as well as ils own ; nor will the addition 
of any number of tumblers preclude the poffibility of open¬ 
ing it. “ By giving (fays he) an uniform motion to the 
tumblers, and prefenting them with a face which exactly 
tallies with the key, they ftill partake, in a very great de¬ 
gree, of the nature ot fixed wards ; and the fecurity of this 
lock is thereby rendered in a proportionable degree defec¬ 
tive. Thus, fuppofe the falfe key to have pafied the 
wards, and to be in contact with the molt prominent of the 
tumblers, the impreflion, which the flighted touch will 
leave on the key, will direct the application of the fiie till 
fufficient fpace is prepared to give it a free paffage. The 
key will then bear upon a more remote tumbler; which 
difficulty being in like manner got over, the lock will Be 
as eafily opened by the falfe as by the true key.” 
This feemingiy infuperable objection to the perfection 
of lock-making, however, our author removes with the 
greateit eafe imaginable, by cauflng the tumblers, which 
projeCt unequally, to prefent a plane furface; whence they 
would require a Separate and unequal motion to difengage 
them; of confequence no diftinCl impreflion could be 
made by them upon the plane furface of the web that 
would give any idea of their pofltions with regard to one 
another, and the conftruCtion of a falfe key w'ould be al¬ 
together impoflible. But, though the principal difficulty 
with regard to Mr. Baron’s lock be now overcome, others 
ftill occur, viz. the difficulty of making locks which are 
conftruCted with tumblers fufficiently durable. The tum¬ 
blers themfelves, he obferves, muft be but (lightly made; 
and, Being expofed to perpetual friClion by the key and 
their own proper motion, they muft foon decay ; and the 
keys of Mr. Baron’s.locks, he alfo obferves, are much lefs 
durable than thofe of any other locks he ever favv. 
With 
