亥姆霍兹论力的守恒

IntroductoryNoteHermannvonHelmholtz;TranslatedbyEdmundAtkinsonHERMANNLUDWIGFERDINANDVONHELMHOLTZwasbornatPotsdam,nearBerlin,onAugust31,1821.Hisfatherwasamanofhighculture,ateacherinthegymnasium,whoseinfluenceensuredtohissonthefoundationsofabroadgeneraleducation.HismotherwasadescendantfromWilliamPenn,theEnglishQuaker.1Helmholtzearlyshowedmathematicalability,andwishedtodevotehislifetothestudyofphysics;butpracticalconsiderationsledhimtotakeupmedicine,andhebecameasurgeoninthePrussianarmy.Hebeganthepublicationoforiginalcontributionstosciencein1842,andforfifty-twoyears,tillhisdeathin1894,hecontinuedtoproduceinanunbrokenstream.Heheldasuccessionofacademicpositions,teachingphysiologyatKönigsberg,Bonn,andHeidelberg,andforthelasttwenty-threeyearsofhislifefillingthechairofphysicsatBerlin.2Thetitlesofhisprofessorships,however,giveaveryinadequateideaofhisrange.Hiscontributionstosciencecovermedicine,physiology,optics,acoustics,mathematics,mechanics,andelectricity.Hisinterestsinscienceandartcametogetherinhisworkonesthetics,andhehadalivelyappreciationofpainting,poetry,andmusic.3ThepracticeofpopularlecturingonscientificsubjectswasalmostunknowninGermanywhenHelmholtzbegan,andhedidmuchtogiveitdignityandtosetastandard.Hisownlectures,asthereaderofthefollowingpaperswillperceive,aremasterpiecesoftheirkind.“Thematter,”saysabiographer,“isdiscussedbyamaster,whobringstobearuponitallhiswealthoflearningandresearch,whilethereistheever-enduringinterestthatattachestoanexpositionbyonewhoisgivingforthfromhisowntreasury.”Itisfortunateforthelaymanwhenascientistandthinkerofthefirstorderhastheskillandtheinclinationtosharewiththeoutsideworldtherichharvestofhisbrilliantandlaboriousresearch.4OntheConservationofForceIntroductiontoaSeriesofLecturesDeliveredatCarlsruheintheWinterof1862–1863HermannvonHelmholtz;TranslatedbyEdmundAtkinsonASIhaveundertakentodeliverhereaseriesoflectures,IthinkthebestwayinwhichIcandischargethatdutywillbetobringbeforeyou,bymeansofasuitableexample,someviewofthespecialcharacterofthosesciencestothestudyofwhichIhavedevotedmyself.Thenaturalsciences,partlyinconsequenceoftheirpracticalapplications,andpartlyfromtheirintellectualinfluenceonthelastfourcenturies,havesoprofoundly,andwithsuchincreasingrapidity,transformedallthe1relationsofthelifeofcivilisednations;theyhavegiventhesenationssuchincreaseofriches,ofenjoymentoflife,ofthepreservationofhealth,ofmeansofindustrialandofsocialintercourse,andevensuchincreaseofpoliticalpower,thateveryeducatedmanwhotriestounderstandtheforcesatworkintheworldinwhichheisliving,evenifhedoesnotwishtoenteruponthestudyofaspecialscience,musthavesomeinterestinthatpeculiarkindofmentallabour,whichworksandactsinthesciencesinquestion.OnaformeroccasionIhavealreadydiscussedthecharacteristicdifferenceswhichexistbetweenthenaturalandthementalsciencesasregardsthekindofscientificwork.Ithenendeavouredtoshowthatitismoreespeciallyinthethoroughconformitywithlawwhichnaturalphenomenaandnaturalproductsexhibit,andinthecomparativeeasewithwhichlawscanbestated,thatthisdifferenceexists.NotthatIwishbyanymeanstodeny,thatthementallifeofindividualsandpeoplesisalsoinconformitywithlaw,asistheobjectofphilosophical,philological,historical,moral,andsocialsciencestoestablish.Butinmentallife,theinfluencesaresointerwoven,thatanydefinitesequencecanbutseldombedemonstrated.InNaturetheconverseisthecase.Ithasbeenpossibletodiscoverthelawoftheoriginandprogressofmanyenormouslyextendedseriesofnaturalphenomenawithsuchaccuracyandcompletenessthatwecanpredicttheirfutureoccurrencewiththegreatestcertainty;orincasesinwhichwehavepowerovertheconditionsunderwhichtheyoccur,wecandirectthemjustaccordingtoourwill.Thegreatestofallinstancesofwhatthehumanmindcaneffectbymeansofawell-recognisedlawofnaturalphenomenaisthataffordedbymodernastronomy.Theonesimplelawofgravitationregulatesthemotionsoftheheavenlybodiesnotonlyofourownplanetarysystem,butalsoofthefarmoredistantdoublestars;fromwhich,eventherayoflight,thequickestofallmessengers,needsyearstoreachoureye;and,justonaccountofthissimpleconformitywithlaw,themotionsofthebodiesinquestioncanbeaccuratelypredictedanddeterminedbothforthepastandforfutureyearsandcenturiestoafractionofaminute.2Onthisexactconformitywithlawdependsalsothecertaintywithwhichweknowhowtotametheimpetuousforceofsteam,andtomakeittheobedientservantofourwants.Onthisconformitydepends,moreover,theintellectualfascinationwhichchainsthephysicisttohissubjects.Itisaninterestofquiteadifferentkindtothatwhichmentalandmoralsciencesafford.Inthelatteritismaninthevariousphasesofhisintellectualactivitywhochainsus.Everygreatdeedofwhichhistorytellsus,everymightypassionwhichartcanrepresent,everypictureofmanners,ofcivicarrangements,ofthecultureofpeoplesofdistantlandsorofremotetimes,seizesandinterestsus,evenifthereisnoexactscientificconnectionamongthem.Wecontinuallyfindpointsofcontactandcomparisoninourconceptionsandfeelings;wegettoknowthehiddencapacitiesanddesiresofthemind,whichintheordinarypeacefulcourseofcivilisedliferemainunawakened.3Itisnottobedeniedthat,inthenaturalsciences,this