LOCK. 
frivance renders very eafy to be done. As this improve¬ 
ment relates only to the efcutcheon, it is obvious that 
every attempt to pick the lock it covers, or to open it by 
means of faife keys, is prevented; a circumftance of no 
fmall importance, when locks of a curious conftruction 
are made ufe of. 
Figs. 9 to 16 reprefent the different parts of Mr. Mar- 
fhall’s efcutcheon. Fig. 9 is a view of the machine as it 
appears upon the door, when fixed over the lock, and co¬ 
vering the key-hole. Fig. 10 is an infide view of the 
fame, fuppofing it to be firft removed from the door. 
A B C D is a brafs box, fattened over the key-hole; it has 
a fquare hole through it, covered by a fmall door E; this 
door is kept (hut by a pin fixed into a fmall lever a, which 
enters a projection from the fide of the door, and thus 
prevents it being opened unlefs the leveris firft drawn back ; 
a fpring b is applied behind the lever to force it outward, 
and another at c always preffes againft the door, and ads 
to throw it open as foon as the lever a is drawn back, 
which is accomplifhed by means of a pin, which comes 
through a groove in the plate; this pin is faltened in a 
fquare bar F, figs. 9 and 13, (llrown feparately in fig. 11.) 
on the front of the plate. The fmall perfpedtive, fig. 15, 
reprefen,ts two brafs cocks, d, d, which fupport the ends 
of a cylindric barrel G, in which is a groove for the bar 
F to Aide backwards and forwards; thefe cocks are fcrewed 
to the plate within-fide, as fhown at dd, figs. 10 and 12, and 
come through an opening in the plate; fo that the bar F 
is in front of the plate. The cylinder G, fig. 15, is the 
common axis for five fmall rollers A, E, S, M, 0 , fig. 9. 
The Itrudure of one of thefe is explained by figs. 13, 14, 
and 16 ; h, fig. 12 and 16, is a circular piece of brafs which 
fits upon the centric wire; this, as is fhown in the lec¬ 
tions, figs. 14 and 16, is thicker at the outiide than the 
middle; and the front views, fig. 13, 14,dhow howarecefs 
is cut, communicating with the centre hole. Now, when 
the five rollers are turned round upon the central barrel 
G, fo that the receffes are all brought into the front, the 
projecting teeth x, x, of the flider F, fig. u, will meet 
with no obftrudion, and may be drawn back fo as to 
open the efcutcheon ; but, when any of the rollers are 
turned round, fo that the thin parts near the centre are 
brought between the teeth of the flider, then the flider 
cannot be withdrawn. The pofition of the roller, when 
the flider is at liberty, is known by bringing five of the 
letters which are engraven on the outiide of the rollers 
■uppermoft, and it is in ihefe letters that the fecret con- 
fifts. But, to render the combination of letters variable, 
the letters are not engraved upon the outfide of the rol¬ 
lers themfeves, but upon a thin brafs hoop l, which is fit¬ 
ted on round the roller; a fpring n is faltened to the rol¬ 
ler, and, prefling upon the infide of the hoop, caufes fuch 
a friCtion, that they go together in general; but when the 
fecret is to be changed, the flider F mult be drawn partly 
back, fo that its teeth x come in the way of the thin parts 
of the rollers, and they cannot, therefore, be turned round ; 
the outiide hoop l is then forced round upon the infide 
one, and a freih letter brought oppofite the recefs; by this 
operation the fecret is altered, and the efcutcheon can¬ 
not be opened till the fame combination is produced. 
Each roller has four letters upon it, in all twenty letters ; 
and the combinations which they are capable of are fo 
numerous, that the chance is ftrongly againft any perfon 
not acquainted with the fecret opening it. Ten guineas 
were voted to Mr. Marlhall, on the 4th of February, 1784, 
for this invention; and the machine itlelf is preferved at 
the fociety’s repofitory in the Adelphi for the infpeCtion 
of the public. 
In the fame volume of the Society’s TranfaClions, we 
find that the filver medal was prefented to Mr. Taylor, 
of Petworth, for his improvement on the latch or fpring- 
bolt of common locks. This is eft'eded by limply re- 
verfing the tumbler, fo that its curved fide ads againft 
two ftubs fixed on the tail of the latch, and thrults back 
the latter with eafe, whether the knob be turned to the 
871 
right or to the left when the lock is opened. Mr. Tay¬ 
lor has alfo, behind the tail of the latch, fixed a guide 
containing a groove, in which runs a fmall friCftion-wheel, 
that ferves to keep the latch in its dired fituation, and at 
the fame time to diminilh its friction ; the arms of his 
tumbler are fomewhat contracted, in order that the latch 
or fpring-bolt may move with greater facility. By this 
conitrudtion, the parts of the tumbler 3 nd latch, which 
are in contadt, move in a line, fo that they pafs over the 
greateft fpace under the fmalleft angle; and the lock itlelf 
may be conftantly tiled for feveral years, without requir¬ 
ing the application of oil. 
The laft lock we lha!l notice is one invented by Mr. A 0 
O. Stanfbury of New York, and for which a patent was 
obtained in London in the year 1806. To underftand 
the nature of this machine without the aftiftance of an 
engraving, we rnuft fuppofe that a flat circular plate is 
fitted to turn round upon the centre pin for the key, and 
that this plate, when turned round, (hoots the bolt, which 
may be done by various means. The locking-part con- 
fills of four, fix, or more, fmall fteel pins, which are re¬ 
ceived in holes made very near each other, through both 
the circular turning plate and the fixed plate beneath it. 
By thefe pins the circular plate is held fall from turning. 
The key has the fame number of pins, and arranged in 
the fame pofition and diftance as the pins in the plate. 
The key being introduced, it is prefted forwards againft: 
the circular plate, and turned round till the pins in it 
come over the pins in the circular plate, and the prrifure 
of the hand forces the pins out of the circular plate, the 
pins in the key occupying the place of them. The plate 
is now relieved, and the key has hold of the plate to turn 
it round and open the lock. Each pin is provided with 
a fpring behind the fixed plate to force it forwards. The 
difficulty of making a falfe key to this lock is very great; 
as any error in the number, fize, pofition, or length, of the 
pins, will prevent it from opening the lock. To avoid 
the danger of impreffions being taken, many marks are 
ftamped upon the circular plate, which are exadly the 
fame as the marks of the real pins; thus an impreflion 
taken from it would only miflead. Mr. Stanfbuiy has 
alfo made an ingenious improvement upon the common 
fpring door-lock. The handle which opens the fpring- 
catch for faftening the door, inftead of requiring to be 
turned round, is made fo that it withdraws the fpring- 
catcli, by pulhing the handle on one fide of the door and 
pulling it on the other. This method is extremely con¬ 
venient; for preffing the handle releafes the lock, and 
continuing the preflure opens the door, and pulling the 
handle on the other fide has the fame effed. A perfon 
with his hands full may open fuch a door by only leaning 
againft the handle. Monthly Mag. vol. xxi. 
LOCK,/ The part of the gun by which fire is (truck.. 
—A gun carries powder and bullets for feven charges and 
difcharges; under the breech of the barrel is one box for 
the powder; a little before the loch, another for the bul¬ 
lets ; behind the cock a charger, which carries the pow¬ 
der to the further end of the lock. Grew .—A hug ; a grap¬ 
ple.—They mult be pradifed in all the locks and gripes of 
wreftling, as need may often be in fight to tugg or grap¬ 
ple, and to dole. Milton on Education .’—‘Any iuclofure s 
Sergefthus, eager with his beak to prefs 
Betwixt the rival gaily and the rock. 
Shuts up the unwieldy centaur in the lock. Dryden. 
A quantity of hair hanging together.—Well might he 
perceive the hanging of her hair in Zeds, fome curled, and 
fome forgotten. Sidney .—A goodly cyprefs, who bowing., 
her fair head over the water, it feemeth ftie looked into it* 
and drefied her green locks by that running river. Sidney, 
His grizly locks, long growen and unbound, 
Diforder’d lning about his Shoulders round. Spcnfcr, 
A tuft.—I fuppofe this letter will find thee picking of 
dailies, or fmeliing to a led, of hay. Addifon ,—The bot- 
tGftlfca 
