HOROLOGY. 
352 
proper perfon could be found to execute his plan with 
equal fuccefs. Mr. Larcum Kendal, one of the commit¬ 
tee, undertook the talk, and fir.ilhed a time-piece on the 
fame conltmclion, or at leaft on the fame principles, which 
was approved by Mr. Wales, in his voyage in company 
with captain'Cook in the years 1772, U773, &c. and which 
Dr. Hutton fays performed even better than Harrifon’s, 
allowing for an acceleration in its rate. Jn confequence 
of this fuccefs, the parliament, to which an appeal was 
made, ordered the refidue of the propofed reward to be 
paid ; in addition to which, the gratuities of the Board 
of Longitude, of the Eaft-India company, and of others, 
contributed to augment the whole fum to about 24,000]. 
Mudgc’s Time-keeper. —In the Defcription of the Time¬ 
keeper, pubiilhed in 1799, ' 5 y Mr. Thomas Kludge, jun. 
there are nine plates, eight of which are taken up in ex¬ 
hibiting the different plans and feclions of the various 
parts feen in different points of view ; they were drawn 
by Mr. Pennington, the original workman employed by 
the two Mudges, father and foil; but, inftead of copying 
any of the plates, we have judged it fufiicient to give a 
drawing and full explanation of the fcapement from Ni- 
choll'on’s Phil. Journal. It is not neceffary to give a par¬ 
ticular account of the calliper of Muage’s time-keeper, 
as it does not differ in any material particular from that 
of chronometers by other makers ; nor is there any thing 
worthy of particular, notice in the fufee, different from 
that of an ordinary watch, except that there is the auxi¬ 
liary fpring, making with it 3. going-fufee of the ordinary 
conftru&ion. The barrel however, which contains the 
main-lpring, is very fimilar to Harrifon’s, and differs from 
ordinary barrels. When the fpring requires to be fet up 
or down, it is done by turning the fpring-barrel and 
ratchet, together with the contained fpring, while the 
click is raifed from the teeth of .’the ratchet, the ar¬ 
bor of the chain-barrel then being ftationary, or revolv¬ 
ing 110 otherwife than according to the flew motion which 
the train regulates. The chain is wound round the fufee 
in a direction which actuates the wheels of the train in a 
backward manner, compared with the motion of an or¬ 
dinary train, which direction of motion requires an ad¬ 
ditional wheel in .the, dial-work; for a fmall wheel of 
45, fixed to the arbor of the co'ntrate-whee), drives another 
cf the fame number of teeth in a proper direction for in¬ 
dicating feconds, on a feparate graduated circle, at a dis¬ 
tance from the centre of the face; nor is the Second, ufu- 
aily called the centre-wheel , placed in the centre of the 
hour and minute circles, (as is common in watches,) 
though oppofite the centre of the face ; but its prolonged 
pivot bears a minute-wheel of 52, driving a fimilar de¬ 
tached minute-wheel, and alfo an attached pinion of 8 
driving an hour-wheel of 96, both which driven wheels 
have cannons to carry tlieir relpeCtjve hands round two 
concentric circles, placed at the other fide of the centre 
of the dial. This method of placing the hands' allows the 
contrate and centre wheels to have linall pivots. 
The numbers of the movement pubiilhed by Kludge 
are as follow: viz. The great wheel has 100 teeth, the 
pinion aching with it 20, the centre-wheel dr fecond- 
whecl 120, the next pinion 16, the third wheel 120, the 
pinion driven by it 15, the contrate-wheel 120, the pinion 
driven by it 12, balance-wheel 15, pallets 2 5 whence it 
IOO 
feems that the fufee revolves in-- or 5 hours, and the 
20 J 
. 120 120 60 . 
contrate-wheel in —— X — 1 = —> or 60 times in the 
16 15 1 
hour, and the value of the train is, according to our method 
„ . rr -r , - 120X 120 X 120 X I J X 2 
of elhmating Harmon s train, -7—-—-- 
f , (6X15X1* 
— 18000 vibrations in an hour, or five in a fecond. With 
this movement, a ft 1 fee with 7-* turns or fpirals in the 
groove actuates the piece thirty-fix hours. But there is 
a face laid down in Mudge’s book for a continuance of 
eight days, the circles for the hours and minutes in which 
are at oppofite fides of the prolonged pivot of the centre- 
wheel arbor, and the hour-circle counts up to 24, which 
is 'certainly more convenient, for allronomical calcula¬ 
tions, than one with only 12 hours. The numbers of 
this movement are as follow: viz. Great wheel 108, pi¬ 
nion on the centre-wheel 12, centre-wheel 128, pinion 
following 12, fecond wheel of the train, or third of the 
whole movement, 120, pinion dihven by it on the next ar¬ 
bor 12, contrate-wheel 120, pinion following on the ba¬ 
lance-wheel arbor 12, crown-wheel 15, pallets 2 ; l'o that 
, , - . . . 128X1*0X120X11X2 
the value ot thetram is-—-—-12000, 
12X12X12 
on a fuppofition that the centre-wheel revolves in an hour; 
but we find from the dial-work, which has what is called 
borrowed minutes, that this wheel revolves in of an 
hour or in 1-7 hours, therefore of 32000 = 18000 is 
the true train by the wheels and pinions before us; the 
liour-liand revolves in of i h '7 = 24''; and the fulee 
revolves in X fr ot an hour, which is = 16 hours; 
therefore a fulee with juft 12 turns will continue to go 
eight days, as was intended. 
The Horology Plate XIII. fig. 90, exhibits the fcape¬ 
ment of this machine ; in which the balance is perfectly 
detached from the train of wheels, except during the ex¬ 
tremely fliort interval of linking out the parts which ferve 
the purpofe of detents. ONEBQ-isthe circumference 
of the balance, vibrating by the aCtion of a fpiral-fpring, 
as ufual, on its axis, CA, DH, palling through the cen¬ 
tre C ; the axis is bent into a crank, AX YD, to make 
room for the other work. LM, ZW, are two rods fixed 
to the crank at the points L and Z, parallel to XY. 
edefrs are fixed parts of the machine. TR is an axis 
concentric with that of the balance, and carrying an arm 
GO nearly at right angles to it, and a l'mall auxiliary 
fpring u, which is wound up whenever the arm G O is 
moved in the direction Oh. p is a curved pallet fixed to 
the axis TR, which receives the tooth of the balance- 
wheel near the axis. This tooth, proceeding along the 
curved furface, by the force of the main-fpring turns the 
axis and its arm G O, and winds up the fpring u. A 
fmall projection at the extremity of the curved furface of 
the pallet p prevents the further progrefs of the tooth, 
when the arm OG has been turned through an arc Oh, 
of about 27 0 ; and confequently the fpring it has been 
wound up through the fame angle or arc, OG A — 27°. 
BS is another axis exaCtly fimilar to TR. It carries its 
arm IO, and fpring v, and the tooth of the balance-wheel 
m winds up the fpring v, by acting on the pallet <7, and is 
detained by a projection, after having carried it through 
an angle of 27 0 , exaClly as in the former cafe. The arcs 
palled through by the arms GO and IO, and marked in 
the figure, are alfo denoted by the fame letters on the rim 
of the balance. 
The effect of this fcapement may be thus explained : 
let the balance be in the quiefeent date, the main-fpring 
being unwound, and the branch or crank in the polition 
reprefented in the figure. If the quielcent points of the 
auxiliary lprings coincide with that of the balanee-fpring, 
the arm GO will juft touch the rod LM, and in like 
manner the arm I O will juft touch the rod W Z; the 
two arms G O and I O in this polition are parallel to the 
line C O above. This pofition of the balance and auxi¬ 
liary fprings remains as long as the main-fpring of the 
machine continues unwound; but,'whenever the action 
of the main-lpring fets the balance-wheel in motion, a 
tooth thereof, meeting with one or other of the pallets p 
or c[, will wind up one of the auxiliary fprings; fuppoie 
it lhould be the fpring u. The arm GO, being carried 
into the polition G k, by the force of the balance-wheel 
aCting on the pallet p, remains in that pofition as long as 
the tooth of the balance-wheel continues locked by the 
projection at the extremity of the pallet p ; and the ba¬ 
lance itfelf, not being at all afteCted by the motion of the 
arm G O, nor by the winding-up of the fpring u, remains 
in its quiefeent polition; confequently no vibration can 
take place, except by the affiftance of fome external force 
to 
