Weight-Driven Clock Weight Selection Guide

Weight-driven clock weight selection determines proper operation where incorrect weight size creates problems including excessively fast striking consuming weight drop too quickly or insufficient power preventing reliable running particularly when pivot holes show wear increasing friction throughout train. Eight-day weight-driven clocks typically use 7-8 pound weights though specific requirements vary substantially between manufacturers and movement designs making universal "8-day weight" specification misleading since actual weight needs depend on mainspring barrel diameter, train gear ratios, escapement design, plus friction levels from bushing condition. Strike train weight requirements differ from time train where strike typically needs less weight than timekeeping side though excessively heavy strike weight creates rapid striking potentially damaging hammer and gong through violent impacts while insufficient strike weight produces sluggish unreliable striking failing to complete hour counts.

Proper weight selection requires empirical testing observing clock operation under various weight loads rather than relying on supplier generic weight categories potentially mismatching specific movement requirements. This guide covers understanding why weight requirements vary between seemingly identical movements through differences in friction levels from bushing condition plus manufacturing tolerances affecting power transmission efficiency, determining proper time train weight through systematic testing using temporary improvised weights enabling observation of reliable eight-day operation versus premature stopping, selecting appropriate strike train weight preventing excessively fast striking from overpowering while ensuring adequate power completing full hour counts, adjusting strike speed through fan governor tightening when loose fan creates rapid uncontrolled striking, plus recognizing when power problems indicate underlying mechanical issues like worn bushings or bent arbors requiring correction before weight selection providing lasting reliable operation rather than temporary compensation for fundamental problems.

Understanding Weight-Driven Clock Power Requirements

Why Weight Requirements Vary Between Clocks

Weight-driven clock power requirements vary substantially between different movements despite similar size and eight-day designation. Primary factors affecting weight needs include mainspring barrel diameter where larger barrels provide greater mechanical advantage enabling lighter weights achieving same torque output. Train gear ratios critically affect power requirements - higher ratio trains multiplying rotational speed more aggressively require more input power overcoming increased friction from additional wheel meshings. Escapement design influences power consumption where recoil escapements showing substantial backward wheel motion during each tick consume more power compared to dead-beat designs minimizing recoil losses.

Additionally, individual movement condition dramatically affects weight requirements. Freshly serviced movement with proper bushings smooth polished pivots and appropriate lubrication runs with minimal friction requiring lighter weights compared to worn movement showing pivot hole wear creating binding plus accumulated contamination increasing friction throughout train. Therefore, two identical movements - one newly serviced, one badly worn - may require substantially different weights achieving reliable operation. This variability explains why generic supplier weight specifications prove inadequate for determining specific movement requirements necessitating empirical testing approach.

Manufacturing tolerances create additional variability even between movements from same manufacturer production period. Hand-fitted components show dimensional variations affecting mesh tightness and friction levels. Some movements assembled during optimal conditions show superior smoothness while others assembled less carefully show increased friction from tight meshes or misaligned components. Additionally, case-to-case variations in weight drop distance affect available energy - clock with 60-inch weight drop provides more total energy compared to clock with 48-inch drop enabling use of lighter weights achieving same eight-day operation duration. Therefore, empirical weight testing specific to individual clock provides only reliable method determining optimal weight selection.

Time Train Versus Strike Train Weight Needs

Time train and strike train typically require different weight sizes optimizing each function separately rather than using identical weights throughout clock. Time train operates continuously throughout eight-day period requiring steady reliable power maintaining pendulum motion against friction and air resistance. Strike train operates intermittently - brief intense power demands during hourly striking followed by long idle periods. This operational difference creates distinct power requirement profiles suggesting optimized weight selection for each train rather than convenience of identical weights potentially compromising one or both functions.

Generally, time train requires heavier weight compared to strike train. Continuous operation accumulates friction losses throughout eight-day period requiring adequate weight providing power reserves accommodating gradual friction increase as lubricant migrates or minor contamination accumulates. Additionally, time train must overcome escapement friction plus pendulum air resistance throughout complete weight drop distance. Strike train operating intermittently accumulates less total friction though instantaneous power during striking may be substantial. However, strike operates perhaps total 30 minutes throughout entire eight-day period compared to time train's continuous 192-hour operation creating dramatically different total energy requirements.

However, practical considerations sometimes favor identical weights despite theoretical optimization suggesting different sizes. Matching weights simplify replacement - single spare weight serves either position rather than maintaining separate spare for each train. Additionally, aesthetic considerations favor symmetrical appearance with matched weights hanging visibly within case. Therefore, clockmakers often compromise selecting single weight size adequate for both trains though this typically means slightly oversized strike weight providing more power than strictly necessary. This conservative approach ensures reliable operation both trains without requiring separate weight inventory or asymmetric appearance potentially bothering aesthetically-sensitive owners.

Impact of Bushing Condition on Weight Requirements

Bushing condition critically affects weight requirements where worn pivot holes increase friction dramatically raising power needs potentially doubling required weight compared to properly bushed movement. Worn holes allow arbor tilting where rotating pivot contacts hole edge creating scraping friction rather than smooth rotation characteristic of properly bushed holes maintaining centered arbor position. Additionally, worn holes showing egg-shaped geometry create variable friction throughout rotation - binding at tight spots, looseness at worn areas - creating irregular power transmission potentially causing intermittent stopping despite adequate average power delivery.

Rathbun screw-on bushings - visible in many old movements as externally-threaded brass cylinders screwed into enlarged holes - represent previous repair attempts addressing worn pivot holes. However, Rathbun bushings create their own problems. Soldering process potentially warps plates affecting alignment. Additionally, Rathbuns position new pivot hole center potentially offset from original location changing depthing throughout train creating tight or loose meshes affecting friction unpredictably. Therefore, movement showing multiple Rathbun bushings may require substantially more or less weight compared to identical movement with proper traditional bushings maintaining original geometry.

Interestingly, removing Rathbun bushings sometimes improves operation despite conventional wisdom suggesting bushings always improve worn holes. Some Rathbuns install incorrectly - wrong position, improper sizing, or damage during installation - creating more problems than original worn holes. Therefore, if movement runs poorly despite adequate weight and proper adjustment, consider experimentally removing Rathbuns observing whether operation improves. Original holes may prove adequate particularly when movement receives thorough cleaning removing accumulated contamination that Rathbun installation attempted compensating for through changed geometry rather than addressing actual contamination problem creating excessive friction.

Determining Proper Time Train Weight

Empirical Testing Method Using Temporary Weights

Determine proper time train weight through empirical testing using temporary improvised weights rather than purchasing potentially incorrect commercial weights based on generic specifications. Create test weight using tin can, plastic bottle, or cloth bag filled with adjustable ballast - metal scraps, nails, BBs, sand, or water. Attach test weight to time train weight cord using secure connection preventing accidental release during testing. Wind movement fully then start pendulum observing clock operation over extended period - ideally complete eight-day cycle though 24-hour minimum test provides useful preliminary indication.

Monitor operation carefully noting any performance changes as weight drops throughout test period. Clock should maintain consistent reliable operation from fully-wound through completely-run-down positions. If clock stops before eight days elapsed, weight is insufficient requiring additional ballast. However, recognize that stopping may indicate mechanical problems rather than simply inadequate weight - worn bushings, bent arbors, or contamination may prevent reliable operation regardless of weight size. Therefore, if adding substantial weight fails achieving eight-day operation, suspect mechanical problems requiring repair rather than continuing weight increases potentially masking fundamental defects.

After identifying minimum weight enabling eight-day operation, add approximately 50% safety margin accounting for gradual friction increase as lubricant migrates plus modest contamination accumulation over years of operation. For example, if clock barely completes eight days on 5-pound test weight, use approximately 7.5-pound operational weight providing power reserve ensuring reliable long-term operation. This conservative approach prevents premature service needs from marginal power delivery while avoiding excessive weight creating unnecessarily high loads throughout train potentially accelerating wear through increased bearing pressures and mesh forces.

Using Fish Scale Method

Alternative weight determination uses fish scale or spring scale measuring actual pulling force required maintaining operation throughout weight drop cycle. Attach scale to weight cord anchoring opposite end to fixed point. Wind clock until scale reads desired test weight - perhaps 7 pounds initially. Allow clock running until weight fully drops observing whether clock completes full eight-day period. If clock stops prematurely, increase test weight repeating cycle. If clock successfully completes eight days, note final scale reading when clock stops providing minimum weight required for that specific movement in its current condition.

This method provides precise weight measurement enabling exact commercial weight selection rather than estimating through improvised ballast weights requiring subsequent weighing determining actual achieved weight. Additionally, scale method enables quick testing multiple weight values without repeatedly adjusting ballast achieving target - simply wind to different scale readings observing results. However, scale method requires leaving clock partially disassembled for testing period enabling scale access to weight cord plus preventing normal case installation potentially affecting weight cord friction from rubbing against case interior surfaces during actual operation.

After determining minimum weight through scale testing, add 50% safety margin as previously described. Therefore, if scale shows 5 pounds when clock stops after eight-day test, use approximately 7.5-pound operational weight. Document determined weight for future reference - record in notebook or mark inside case enabling easy identification if weights are subsequently removed requiring later reinstallation without repeating complete testing procedure. Additionally, note movement condition during testing - if movement subsequently receives professional servicing improving bushing condition, required weight may decrease substantially requiring retesting determining optimized weight for improved condition.

Recognizing Power Problems Versus Weight Problems

Distinguish between insufficient weight and mechanical power problems preventing reliable operation regardless of weight size. Insufficient weight shows characteristic gradual performance degradation - clock runs reliably when fully wound but shows increasing beat irregularity as weight drops eventually stopping before eight-day period completes. Adding weight eliminates problem enabling full eight-day operation. Mechanical power problems show different pattern - clock may stop at same point in weight drop cycle regardless of total weight, or shows intermittent stopping and restarting suggesting friction binding at specific rotation positions rather than generalized inadequate power.

Additionally, observe whether clock stops during normal running or specifically during certain operational events. Clock stopping consistently shortly before hour suggests inadequate power lifting warning lever preparing for strike release. Clock stopping randomly throughout day suggests mechanical binding or escapement problems. Clock stopping when case is bumped or moved suggests loose components or improper beat adjustment. These patterns indicate mechanical problems requiring repair rather than simply heavier weights masking underlying defects through brute-force power increase potentially creating other problems from excessive loads.

Test for mechanical binding by manually rotating train wheels observing smooth consistent resistance versus variable binding throughout rotation. With weights removed, slowly rotate time train great wheel observing whether smooth consistent rotation occurs or whether specific positions show increased resistance suggesting tight mesh bent arbor or other mechanical problems. Additionally, verify proper lubrication at all pivot points - dry pivots create excessive friction no amount of weight overcomes without risking damage from excessive bearing loads. Therefore, before concluding inadequate weight causes poor operation, verify mechanical soundness through systematic inspection and testing eliminating mechanical causes before pursuing weight solutions.

Strike Train Weight and Speed Adjustment

Determining Proper Strike Weight

Strike train weight requirements typically less than time train though adequate weight ensures reliable complete hour counts without hammer failing to contact gong properly or strike mechanism jamming mid-count. Start strike weight testing using approximately 75-80% of determined time train weight - if time train uses 8 pounds, try 6-6.5 pounds for strike train. Wind strike train fully then manually trip strike mechanism observing complete hour count. Strike should operate smoothly completing full twelve-hour count without hesitation or binding. If strike stops prematurely or shows sluggish operation failing to properly lift hammer, increase weight incrementally testing after each addition.

However, excessive strike weight creates rapid violent striking potentially damaging hammer pivot, hammer leather, or gong mounting from repeated impacts. Additionally, overly rapid striking sounds harsh rather than pleasant creating undesirable acoustic character. Therefore, avoid excessive strike weight even when heavier weight successfully completes counts - select minimum weight enabling reliable striking rather than maximum weight creating fastest possible operation. This conservative approach balances reliable function against longevity and acoustic quality maximizing clock operational life while maintaining pleasant strike character.

Strike weight requirements particularly sensitive to fan governor condition. Loose fan provides minimal speed regulation enabling rapid striking even with light weight. Tight fan creates substantial speed regulation requiring heavier weight overcoming increased friction. Therefore, strike weight and fan adjustment are interdependent - optimize fan tension first achieving desired strike speed with moderate weight rather than compensating for incorrect fan adjustment through extreme weight selection creating suboptimal compromises. Proper approach adjusts fan achieving desired speed characteristic then selects minimum weight reliably driving properly-adjusted mechanism rather than using weight selection compensating for improper fan adjustment.

Fan Governor Adjustment for Strike Speed Control

Fan governor - spinning brass or steel fan attached to strike train - regulates strike speed through air resistance preventing runaway striking from weight-driven power. Fan mounts on arbor using friction fit enabling slight slipping when strike mechanism stops preventing damage from sudden stopping forces. However, excessively loose fan provides inadequate speed regulation creating rapid uncontrolled striking. Conversely, excessively tight fan creates excessive friction requiring heavy strike weight overcoming resistance plus potentially preventing reliable operation with appropriate weight.

Test fan tension by attempting manual rotation with strike train static. Properly adjusted fan requires modest rotational force - similar effort rotating minute hand when setting time. Fan rotating freely with minimal resistance indicates excessive looseness requiring tightening. Fan refusing rotation or requiring substantial force indicates excessive tightness requiring loosening. Adjust fan tension by carefully expanding or contracting friction fit at arbor mounting point. Some fans use set screw enabling tension adjustment. Others use friction arbor requiring careful spreading or compressing achieving proper tension without damaging fan or arbor.

After adjusting fan tension, test strike operation observing speed characteristic. Proper strike speed enables easy counting without strikes blurring together - perhaps 1-2 second intervals between consecutive strikes creating measured dignified cadence rather than rapid machine-gun striking or sluggish delayed striking. Compare strike speed to other similar clocks or online videos showing proper operation. If strike remains too fast despite proper fan tension, consider lighter strike weight. If strike remains too slow, verify fan isn't binding on adjacent components creating additional friction beyond intended air resistance plus verify adequate strike weight provides power overcoming necessary friction levels.

When Strike Speed Indicates Mechanical Problems

Excessively rapid striking despite proper fan adjustment and moderate strike weight suggests mechanical problems requiring correction rather than attempting compensation through weight or fan modifications. Loose fan mounting allowing fan complete free-spinning creates runaway striking no amount of weight reduction corrects without risking insufficient power for reliable operation. Inspect fan verifying secure mounting providing designed friction fit rather than loose sloppy mounting enabling free rotation. Tighten fan mounting as needed though avoid excessive tightening preventing designed slipping action protecting mechanism during strike termination.

Additionally, rapid striking may indicate problems with count wheel mechanism or warning wheel affecting strike train release timing. Strike train should show brief hesitation at warning position before full release enabling controlled measured striking. Absence of proper warning action creates sudden violent release producing rapid harsh striking regardless of weight or fan adjustment. Verify warning mechanism operates properly creating appropriate hesitation before strike release. If warning mechanism shows problems, address these mechanical issues before attempting strike speed optimization through weight or fan modifications.

Conversely, sluggish striking failing to complete counts despite heavy strike weight suggests mechanical binding requiring diagnosis and correction. Possible causes include tight pivot holes, bent arbor creating binding during rotation, damaged teeth causing improper meshing, or contamination creating excessive friction. Systematic inspection identifies specific problems - visually inspect all pivots for smooth rotation, verify wheels show proper mesh without binding, clean movement thoroughly removing accumulated contamination. After mechanical problems are corrected, retest strike weight requirements - properly-serviced movement typically requires substantially less weight compared to worn contaminated movement creating false impression of inadequate weight when actual problem is excessive friction from poor mechanical condition.

FAQs

What size weights do I need for my 8-day weight-driven clock?

Eight-day weight-driven clocks typically use 7-8 pound weights for time train though specific requirements vary substantially between manufacturers and movement designs making empirical testing essential rather than relying on generic specifications. Determine proper weight through systematic testing using temporary improvised weights filled with adjustable ballast like metal scraps nails or sand. Attach test weight to time train cord then wind movement fully observing operation over complete eight-day cycle. If clock stops before eight days elapsed weight is insufficient requiring additional ballast. After identifying minimum weight enabling eight-day operation add approximately 50% safety margin accounting for gradual friction increase as lubricant migrates plus modest contamination accumulation. For example if clock barely completes eight days on 5-pound test weight use approximately 7.5-pound operational weight providing power reserve ensuring reliable long-term operation. Strike train typically requires less weight than time train where starting approximately 75-80% of time train weight provides good initial estimate requiring adjustment based on observed strike speed and reliability. However recognize that weight requirements depend critically on movement condition where freshly serviced movement with proper bushings requires substantially less weight compared to worn movement showing pivot hole wear creating binding throughout train. Therefore movements showing multiple Rathbun bushings or other evidence of previous service attempts may require heavier weights compensating for increased friction from improper repairs or underlying mechanical problems requiring professional correction before optimal weight selection becomes possible.

Why does my weight-driven clock strike too fast?

Weight-driven clock striking too fast typically indicates loose fan governor failing to provide adequate air resistance regulating strike speed or excessively heavy strike weight overpowering properly-adjusted fan creating rapid uncontrolled striking. Test fan tension by attempting manual rotation with strike train static where properly adjusted fan requires modest rotational force similar to rotating minute hand when setting time. Fan rotating freely with minimal resistance indicates excessive looseness requiring tightening through careful adjustment of friction fit at arbor mounting point. After achieving proper fan tension test strike operation observing speed characteristic where proper strike enables easy counting with 1-2 second intervals between consecutive strikes rather than rapid machine-gun striking. If strike remains too fast despite proper fan tension consider lighter strike weight starting approximately 75-80% of time train weight then adjusting based on observed operation. However excessively rapid striking despite proper fan adjustment and moderate weight suggests mechanical problems like completely loose fan mounting allowing free-spinning creating runaway striking. Inspect fan verifying secure mounting providing designed friction fit rather than loose sloppy mounting enabling free rotation. Additionally rapid striking may indicate problems with count wheel mechanism or warning wheel affecting strike train release timing where absence of proper warning action creates sudden violent release producing rapid harsh striking regardless of weight or fan adjustment. Therefore systematic diagnosis identifying specific cause guides appropriate remedy whether fan adjustment weight modification or mechanical repair correcting underlying problems rather than attempting compensation through adjustments masking fundamental defects.

Should time and strike trains use same weight size?

Time and strike trains theoretically benefit from different weight sizes optimizing each function separately though practical considerations sometimes favor identical weights simplifying replacement and providing symmetrical aesthetic appearance. Time train operates continuously throughout eight-day period requiring steady reliable power maintaining pendulum motion against friction and air resistance accumulating substantial total energy consumption. Strike train operates intermittently with brief intense power demands during hourly striking followed by long idle periods where total operation perhaps 30 minutes throughout entire eight-day period compared to time train continuous 192-hour operation. Therefore strike train typically requires less weight than time train where starting approximately 75-80% of time train weight provides good initial estimate. However matching weights simplify replacement where single spare weight serves either position rather than maintaining separate spare for each train. Additionally aesthetic considerations favor symmetrical appearance with matched weights hanging visibly within case. Therefore clockmakers often compromise selecting single weight size adequate for both trains though this typically means slightly oversized strike weight providing more power than strictly necessary. This conservative approach ensures reliable operation both trains without requiring separate weight inventory or asymmetric appearance. However if strike speed becomes problematic from excessive weight creating too-rapid striking despite proper fan adjustment then different weight sizes become necessary optimizing strike speed independently from time train power requirements where aesthetic compromise accepts asymmetric weights favoring proper function over matched appearance.

How do I know if my clock needs heavier or lighter weights?

Determine whether clock needs heavier or lighter weights by observing specific operational characteristics distinguishing between insufficient power and excessive power creating different problem patterns. Insufficient weight shows characteristic gradual performance degradation where clock runs reliably when fully wound but shows increasing beat irregularity as weight drops eventually stopping before eight-day period completes. Adding weight eliminates problem enabling full eight-day operation confirming inadequate weight as cause. For strike train insufficient weight creates sluggish operation failing to complete hour counts or producing weak hammer strikes barely contacting gong. Conversely excessive weight rarely creates problems in time train though overly heavy strike weight produces rapid violent striking potentially damaging hammer and gong plus creating harsh unpleasant acoustic character. Therefore if strike operates too rapidly despite proper fan governor adjustment lighter strike weight becomes necessary slowing operation to appropriate measured cadence. However distinguish between weight problems and mechanical problems where clock stopping at same point in weight drop cycle regardless of total weight suggests friction binding at specific rotation positions rather than generalized inadequate power. Additionally clock showing intermittent stopping and restarting indicates mechanical binding or escapement problems rather than insufficient weight. Test for mechanical binding by manually rotating train wheels observing smooth consistent resistance versus variable binding throughout rotation before concluding weight adjustment necessary rather than mechanical repair addressing underlying problems creating excessive friction no amount of weight overcomes without risking damage.

Can I make my own weights for weight-driven clock?

Yes you can make improvised weights using readily-available materials providing functional though perhaps aesthetically inferior alternatives to commercial cast-iron weights. Create weights using tin cans plastic bottles or cloth bags filled with dense ballast including metal scraps wheel weights rusty bolts steel BBs sand or water for temporary testing. For permanent installation consider melting lead on stove creating custom-weight castings poured into appropriate molds though lead handling requires proper safety precautions including ventilation and avoiding food-preparation areas. Alternatively fill metal cans with concrete creating permanent weights though concrete lower density compared to lead or iron requires larger volume achieving desired weight potentially creating clearance problems within case. When making custom weights ensure secure attachment preventing accidental release during operation where weight cord should attach through reinforced connection point rather than simply tying around can or bottle potentially failing under continuous stress. Additionally consider aesthetic appearance where visible weights benefit from neat professional appearance rather than obviously improvised construction potentially detracting from clock overall presentation. However for clocks where weights hide completely within case functional considerations outweigh aesthetics making improvised weights perfectly acceptable solution avoiding commercial weight purchase expense. Weigh completed improvised weights using bathroom scale or hanging scale documenting actual achieved weight for future reference enabling replication if weights require replacement. Remember that weight requirements may change after movement receives professional servicing improving bushing condition potentially reducing required weight substantially making permanent custom weight investment premature until movement achieves final optimized mechanical condition.

What are Rathbun bushings and should I remove them?

Rathbun bushings are screw-on externally-threaded brass cylinders visible in many old movements representing previous repair attempts addressing worn pivot holes without proper traditional bushing requiring specialized tools and skills. Rathbuns install by enlarging worn pivot hole to standard thread size then screwing bushing into hole using solder securing position. However Rathbuns create multiple problems where soldering process potentially warps plates affecting alignment plus Rathbuns position new pivot hole center potentially offset from original location changing depthing throughout train creating tight or loose meshes affecting friction unpredictably. Therefore movement showing multiple Rathbun bushings may require substantially different weights compared to identical movement with proper traditional bushings maintaining original geometry. Interestingly removing Rathbun bushings sometimes improves operation despite conventional wisdom suggesting bushings always improve worn holes where some Rathbuns install incorrectly through wrong position improper sizing or installation damage creating more problems than original worn holes. Therefore if movement runs poorly despite adequate weight and proper adjustment consider experimentally removing Rathbuns observing whether operation improves. Original holes may prove adequate particularly when movement receives thorough cleaning removing accumulated contamination that Rathbun installation attempted compensating for through changed geometry rather than addressing actual contamination problem. However recognize that Rathbun removal exposes worn holes potentially requiring proper traditional bushing for long-term reliable operation though short-term testing without Rathbuns provides diagnostic information guiding repair decisions. Proper long-term solution removes Rathbuns plus installs traditional bushings restoring original geometry and providing smooth properly-centered pivot operation enabling optimal weight selection and reliable long-term operation.

How often should I retest weight requirements?

Retest weight requirements after any significant service work including professional movement overhaul bushing installation or major component replacement potentially changing friction levels throughout train affecting power requirements. Freshly serviced movement typically requires substantially less weight compared to pre-service condition where improved bushing plus proper lubrication dramatically reduces friction enabling lighter weights achieving same eight-day operation. Conversely movement showing gradual performance degradation over years may benefit from heavier weights compensating for increasing friction from lubricant migration and modest contamination accumulation though recognize that continuing weight increases mask progressive deterioration eventually requiring proper service rather than indefinite weight compensation. Additionally retest weights if clock relocated to different case potentially changing weight drop distance affecting available energy where longer drop provides more total energy enabling lighter weights while shorter drop requires heavier weights achieving same operational duration. Document determined weights including date movement condition and any relevant service history enabling future comparison tracking performance trends over time. However avoid obsessive retesting absent specific operational problems - if clock runs reliably maintaining proper time and strike operation weight selection is adequate regardless of whether theoretical optimization might suggest modest adjustment. Focus testing efforts on clocks showing actual performance problems rather than pursuing theoretical optimization in properly-functioning clocks risking creating problems from unnecessary modifications to working systems.