Ì«×ÓүС˵Íø > Ó¢Óïµç×ÓÊé > a history of science-4 >

µÚ3½Ú

a history of science-4-µÚ3½Ú

С˵£º a history of science-4 ×ÖÊý£º ÿҳ4000×Ö

°´¼üÅÌÉÏ·½Ïò¼ü ¡û »ò ¡ú ¿É¿ìËÙÉÏÏ·­Ò³£¬°´¼üÅÌÉ쵀 Enter ¼ü¿É»Øµ½±¾ÊéĿ¼ҳ£¬°´¼üÅÌÉÏ·½Ïò¼ü ¡ü ¿É»Øµ½±¾Ò³¶¥²¿£¡
¡ª¡ª¡ª¡ªÎ´ÔĶÁÍꣿ¼ÓÈëÊéÇ©ÒѱãÏ´μÌÐøÔĶÁ£¡



ee¡£


HENRY¡¡CAVENDISH

This¡¡work¡¡of¡¡Black's¡¡was¡¡followed¡¡by¡¡the¡¡equally¡¡important¡¡work¡¡of¡¡his¡¡former¡¡pupil£»¡¡Henry¡¡Cavendish¡¡£¨1731¡­1810£©£»¡¡whose¡¡discovery¡¡of¡¡the¡¡composition¡¡of¡¡many¡¡substances£»¡¡notably¡¡of¡¡nitric¡¡acid¡¡and¡¡of¡¡water£»¡¡was¡¡of¡¡great¡¡importance£»¡¡adding¡¡another¡¡link¡¡to¡¡the¡¡important¡¡chain¡¡of¡¡evidence¡¡against¡¡the¡¡phlogiston¡¡theory¡£¡¡Cavendish¡¡is¡¡one¡¡of¡¡the¡¡most¡¡eccentric¡¡figures¡¡in¡¡the¡¡history¡¡of¡¡science£»¡¡being¡¡widely¡¡known¡¡in¡¡his¡¡own¡¡time¡¡for¡¡his¡¡immense¡¡wealth¡¡and¡¡brilliant¡¡intellect£»¡¡and¡¡also¡¡for¡¡his¡¡peculiarities¡¡and¡¡his¡¡morbid¡¡sensibility£»¡¡which¡¡made¡¡him¡¡dread¡¡society£»¡¡and¡¡probably¡¡did¡¡much¡¡in¡¡determining¡¡his¡¡career¡£¡¡Fortunately¡¡for¡¡him£»¡¡and¡¡incidentally¡¡for¡¡the¡¡cause¡¡of¡¡science£»¡¡he¡¡was¡¡able¡¡to¡¡pursue¡¡laboratory¡¡investigations¡¡without¡¡being¡¡obliged¡¡to¡¡mingle¡¡with¡¡his¡¡dreaded¡¡fellow¡­mortals£»¡¡his¡¡every¡¡want¡¡being¡¡provided¡¡for¡¡by¡¡the¡¡immense¡¡fortune¡¡inherited¡¡from¡¡his¡¡father¡¡and¡¡an¡¡uncle¡£

When¡¡a¡¡young¡¡man£»¡¡as¡¡a¡¡pupil¡¡of¡¡Dr¡£¡¡Black£»¡¡he¡¡had¡¡become¡¡imbued¡¡with¡¡the¡¡enthusiasm¡¡of¡¡his¡¡teacher£»¡¡continuing¡¡Black's¡¡investigations¡¡as¡¡to¡¡the¡¡properties¡¡of¡¡carbonic¡­acid¡¡gas¡¡when¡¡free¡¡and¡¡in¡¡combination¡£¡¡One¡¡of¡¡his¡¡first¡¡investigations¡¡was¡¡reported¡¡in¡¡1766£»¡¡when¡¡he¡¡communicated¡¡to¡¡the¡¡Royal¡¡Society¡¡his¡¡experiments¡¡for¡¡ascertaining¡¡the¡¡properties¡¡of¡¡carbonic¡­acid¡¡and¡¡hydrogen¡¡gas£»¡¡in¡¡which¡¡he¡¡first¡¡showed¡¡the¡¡possibility¡¡of¡¡weighing¡¡permanently¡¡elastic¡¡fluids£»¡¡although¡¡Torricelli¡¡had¡¡before¡¡this¡¡shown¡¡the¡¡relative¡¡weights¡¡of¡¡a¡¡column¡¡of¡¡air¡¡and¡¡a¡¡column¡¡of¡¡mercury¡£¡¡Other¡¡important¡¡experiments¡¡were¡¡continued¡¡by¡¡Cavendish£»¡¡and¡¡in¡¡1784¡¡he¡¡announced¡¡his¡¡discovery¡¡of¡¡the¡¡composition¡¡of¡¡water£»¡¡thus¡¡robbing¡¡it¡¡of¡¡its¡¡time¡­honored¡¡position¡¡as¡¡an¡¡¡¨element¡£¡¨¡¡But¡¡his¡¡claim¡¡to¡¡priority¡¡in¡¡this¡¡discovery¡¡was¡¡at¡¡once¡¡disputed¡¡by¡¡his¡¡fellow¡­countryman¡¡James¡¡Watt¡¡and¡¡by¡¡the¡¡Frenchman¡¡Lavoisier¡£¡¡Lavoisier's¡¡claim¡¡was¡¡soon¡¡disallowed¡¡even¡¡by¡¡his¡¡own¡¡countrymen£»¡¡but¡¡for¡¡many¡¡years¡¡a¡¡bitter¡¡controversy¡¡was¡¡carried¡¡on¡¡by¡¡the¡¡partisans¡¡of¡¡Watt¡¡and¡¡Cavendish¡£¡¡¡¡The¡¡two¡¡principals£»¡¡however£»¡¡seem¡£¡¡never¡¡to¡¡have¡¡entered¡¡into¡¡this¡¡controversy¡¡with¡¡anything¡¡like¡¡the¡¡same¡¡ardor¡¡as¡¡some¡¡of¡¡their¡¡successors£»¡¡as¡¡they¡¡remained¡¡on¡¡the¡¡best¡¡of¡¡terms¡££§1£§¡¡It¡¡is¡¡certain£»¡¡at¡¡any¡¡rate£»¡¡that¡¡Cavendish¡¡announced¡¡his¡¡discovery¡¡officially¡¡before¡¡Watt¡¡claimed¡¡that¡¡the¡¡announcement¡¡had¡¡been¡¡previously¡¡made¡¡by¡¡him£»¡¡¡¨and£»¡¡whether¡¡right¡¡or¡¡wrong£»¡¡the¡¡honor¡¡of¡¡scientific¡¡discoveries¡¡seems¡¡to¡¡be¡¡accorded¡¡naturally¡¡to¡¡the¡¡man¡¡who¡¡first¡¡publishes¡¡a¡¡demonstration¡¡of¡¡his¡¡discovery¡£¡¨¡¡Englishmen¡¡very¡¡generally¡¡admit¡¡the¡¡justness¡¡of¡¡Cavendish's¡¡claim£»¡¡although¡¡the¡¡French¡¡scientist¡¡Arago£»¡¡after¡¡reviewing¡¡the¡¡evidence¡¡carefully¡¡in¡¡1833£»¡¡decided¡¡in¡¡favor¡¡of¡¡Watt¡£

It¡¡appears¡¡that¡¡something¡¡like¡¡a¡¡year¡¡before¡¡Cavendish¡¡made¡¡known¡¡his¡¡complete¡¡demonstration¡¡of¡¡the¡¡composition¡¡of¡¡water£»¡¡Watt¡¡communicated¡¡to¡¡the¡¡Royal¡¡Society¡¡a¡¡suggestion¡¡that¡¡water¡¡was¡¡composed¡¡of¡¡¡¨dephlogisticated¡¡air¡¡£¨oxygen£©¡¡and¡¡phlogiston¡¡£¨hydrogen£©¡¡deprived¡¡of¡¡part¡¡of¡¡its¡¡latent¡¡heat¡£¡¨¡¡Cavendish¡¡knew¡¡of¡¡the¡¡suggestion£»¡¡but¡¡in¡¡his¡¡experiments¡¡refuted¡¡the¡¡idea¡¡that¡¡the¡¡hydrogen¡¡lost¡¡any¡¡of¡¡its¡¡latent¡¡heat¡£¡¡Furthermore£»¡¡Watt¡¡merely¡¡suggested¡¡the¡¡possible¡¡composition¡¡without¡¡proving¡¡it£»¡¡although¡¡his¡¡idea¡¡was¡¡practically¡¡correct£»¡¡if¡¡we¡¡can¡¡rightly¡¡interpret¡¡the¡¡vagaries¡¡of¡¡the¡¡nomenclature¡¡then¡¡in¡¡use¡£¡¡But¡¡had¡¡Watt¡¡taken¡¡the¡¡steps¡¡to¡¡demonstrate¡¡his¡¡theory£»¡¡the¡¡great¡¡¡¨Water¡¡Controversy¡¨¡¡would¡¡have¡¡been¡¡avoided¡£¡¡Cavendish's¡¡report¡¡of¡¡his¡¡discovery¡¡to¡¡the¡¡Royal¡¡Society¡¡covers¡¡something¡¡like¡¡forty¡¡pages¡¡of¡¡printed¡¡matter¡£¡¡In¡¡this¡¡he¡¡shows¡¡how£»¡¡by¡¡passing¡¡an¡¡electric¡¡spark¡¡through¡¡a¡¡closed¡¡jar¡¡containing¡¡a¡¡mixture¡¡of¡¡hydrogen¡¡gas¡¡and¡¡oxygen£»¡¡water¡¡is¡¡invariably¡¡formed£»¡¡apparently¡¡by¡¡the¡¡union¡¡of¡¡the¡¡two¡¡gases¡£¡¡The¡¡experiment¡¡was¡¡first¡¡tried¡¡with¡¡hydrogen¡¡and¡¡common¡¡air£»¡¡the¡¡oxygen¡¡of¡¡the¡¡air¡¡uniting¡¡with¡¡the¡¡hydrogen¡¡to¡¡form¡¡water£»¡¡leaving¡¡the¡¡nitrogen¡¡of¡¡the¡¡air¡¡still¡¡to¡¡be¡¡accounted¡¡for¡£¡¡With¡¡pure¡¡oxygen¡¡and¡¡hydrogen£»¡¡however£»¡¡Cavendish¡¡found¡¡that¡¡pure¡¡water¡¡was¡¡formed£»¡¡leaving¡¡slight¡¡traces¡¡of¡¡any¡¡other£»¡¡substance¡¡which¡¡might¡¡not¡¡be¡¡interpreted¡¡as¡¡being¡¡Chemical¡¡impurities¡£¡¡There¡¡was¡¡only¡¡one¡¡possible¡¡explanation¡¡of¡¡this¡¡phenomenonthat¡¡hydrogen¡¡and¡¡oxygen£»¡¡when¡¡combined£»¡¡form¡¡water¡£

¡¨By¡¡experiments¡¡with¡¡the¡¡globe¡¡it¡¡appeared£»¡¨¡¡wrote¡¡Cavendish£»¡¡¡¨that¡¡when¡¡inflammable¡¡and¡¡common¡¡air¡¡are¡¡exploded¡¡in¡¡a¡¡proper¡¡proportion£»¡¡almost¡¡all¡¡the¡¡inflammable¡¡air£»¡¡and¡¡near¡¡one¡­fifth¡¡the¡¡common¡¡air£»¡¡lose¡¡their¡¡elasticity¡¡and¡¡are¡¡condensed¡¡into¡¡dew¡£¡¡And¡¡by¡¡this¡¡experiment¡¡it¡¡appears¡¡that¡¡this¡¡dew¡¡is¡¡plain¡¡water£»¡¡and¡¡consequently¡¡that¡¡almost¡¡all¡¡the¡¡inflammable¡¡air¡¡is¡¡turned¡¡into¡¡pure¡¡water¡£

¡¨In¡¡order¡¡to¡¡examine¡¡the¡¡nature¡¡of¡¡the¡¡matter¡¡condensed¡¡on¡¡firing¡¡a¡¡mixture¡¡of¡¡dephlogisticated¡¡and¡¡inflammable¡¡air£»¡¡I¡¡took¡¡a¡¡glass¡¡globe£»¡¡holding¡¡8800¡¡grain¡¡measures£»¡¡furnished¡¡with¡¡a¡¡brass¡¡cock¡¡and¡¡an¡¡apparatus¡¡for¡¡firing¡¡by¡¡electricity¡£¡¡¡¡This¡¡globe¡¡was¡¡well¡¡exhausted¡¡by¡¡an¡¡air¡­pump£»¡¡and¡¡then¡¡filled¡¡with¡¡a¡¡mixture¡¡of¡¡inflammable¡¡and¡¡dephlogisticated¡¡air¡¡by¡¡shutting¡¡the¡¡cock£»¡¡fastening¡¡the¡¡bent¡¡glass¡¡tube¡¡into¡¡its¡¡mouth£»¡¡and¡¡letting¡¡up¡¡the¡¡end¡¡of¡¡it¡¡into¡¡a¡¡glass¡¡jar¡¡inverted¡¡into¡¡water¡¡and¡¡containing¡¡a¡¡mixture¡¡of¡¡19£»500¡¡grain¡¡measures¡¡of¡¡dephlogisticated¡¡air£»¡¡and¡¡37£»000¡¡of¡¡inflammable¡¡air£»¡¡so¡¡that£»¡¡upon¡¡opening¡¡the¡¡cock£»¡¡some¡¡of¡¡this¡¡mixed¡¡air¡¡rushed¡¡through¡¡the¡¡bent¡¡tube¡¡and¡¡filled¡¡the¡¡globe¡£¡¡The¡¡cock¡¡was¡¡then¡¡shut¡¡and¡¡the¡¡included¡¡air¡¡fired¡¡by¡¡electricity£»¡¡by¡¡means¡¡of¡¡which¡¡almost¡¡all¡¡of¡¡it¡¡lost¡¡its¡¡elasticity¡¡£¨was¡¡condensed¡¡into¡¡water¡¡vapors£©¡£¡¡The¡¡cock¡¡was¡¡then¡¡again¡¡opened¡¡so¡¡as¡¡to¡¡let¡¡in¡¡more¡¡of¡¡the¡¡same¡¡air¡¡to¡¡supply¡¡the¡¡place¡¡of¡¡that¡¡destroyed¡¡by¡¡the¡¡explosion£»¡¡which¡¡was¡¡again¡¡fired£»¡¡and¡¡the¡¡operation¡¡continued¡¡till¡¡almost¡¡the¡¡whole¡¡of¡¡the¡¡mixture¡¡was¡¡let¡¡into¡¡the¡¡globe¡¡and¡¡exploded¡£¡¡¡¡By¡¡this¡¡means£»¡¡though¡¡the¡¡globe¡¡held¡¡not¡¡more¡¡than¡¡a¡¡sixth¡¡part¡¡of¡¡the¡¡mixture£»¡¡almost¡¡the¡¡whole¡¡of¡¡it¡¡was¡¡exploded¡¡therein¡¡without¡¡any¡¡fresh¡¡exhaustion¡¡of¡¡the¡¡globe¡£¡¨

At¡¡first¡¡this¡¡condensed¡¡matter¡¡was¡¡¡¨acid¡¡to¡¡the¡¡taste¡¡and¡¡contained¡¡two¡¡grains¡¡of¡¡nitre£»¡¨¡¡but¡¡Cavendish£»¡¡suspecting¡¡that¡¡this¡¡was¡¡due¡¡to¡¡impurities£»¡¡tried¡¡another¡¡experiment¡¡that¡¡proved¡¡conclusively¡¡that¡¡his¡¡opinions¡¡were¡¡correct¡£¡¡¡¨I¡¡therefore¡¡made¡¡another¡¡experiment£»¡¨¡¡he¡¡says£»¡¡¡¨with¡¡some¡¡more¡¡of¡¡the¡¡same¡¡air¡¡from¡¡plants¡¡in¡¡which¡¡the¡¡proportion¡¡of¡¡inflammable¡¡air¡¡was¡¡greater£»¡¡so¡¡that¡¡the¡¡burnt¡¡air¡¡was¡¡almost¡¡completely¡¡phlogisticated£»¡¡its¡¡standard¡¡being¡¡one¡­tenth¡£¡¡The¡¡condensed¡¡liquor¡¡was¡¡then¡¡not¡¡at¡¡all¡¡acid£»¡¡but¡¡seemed¡¡pure¡¡water¡£¡¨

From¡¡these¡¡experiments¡¡he¡¡concludes¡¡¡¨that¡¡when¡¡a¡¡mixture¡¡of¡¡inflammable¡¡and¡¡dephlogisticated¡¡air¡¡is¡¡exploded£»¡¡in¡¡such¡¡proportions¡¡that¡¡the¡¡burnt¡¡air¡¡is¡¡not¡¡much¡¡phlogisticated£»¡¡the¡¡condensed¡¡liquor¡¡contains¡¡a¡¡little¡¡acid¡¡which¡¡is¡¡always¡¡of¡¡the¡¡nitrous¡¡kind£»¡¡whatever¡¡substance¡¡the¡¡dephlogisticated¡¡air¡¡is¡¡procured¡¡from£»¡¡but¡¡if¡¡the¡¡proportion¡¡be¡¡such¡¡that¡¡the¡¡burnt¡¡air¡¡is¡¡almost¡¡entirely¡¡phlogisticated£»¡¡the¡¡condensed¡¡liquor¡¡is¡¡not¡¡at¡¡all¡¡acid£»¡¡but¡¡seems¡¡pure¡¡water£»¡¡without¡¡any¡¡addition¡¡whatever¡£¡¨£§2£§

These¡¡same¡¡experiments£»¡¡which¡¡were¡¡undertaken¡¡to¡¡discover¡¡the¡¡composition¡¡of¡¡water£»¡¡led¡¡him¡¡to¡¡discover¡¡also¡¡the¡¡composition¡¡of¡¡nitric¡¡acid¡£¡¡He¡¡had¡¡observed¡¡that£»¡¡in¡¡the¡¡combustion¡¡of¡¡hydrogen¡¡gas¡¡with¡¡common¡¡air£»¡¡the¡¡water¡¡was¡¡slightly¡¡tinged¡¡with¡¡acid£»¡¡but¡¡that¡¡this¡¡was¡¡not¡¡the¡¡case¡¡when¡¡pure¡¡oxygen¡¡gas¡¡was¡¡used¡£¡¡¡¡Acting¡¡upon¡¡this¡¡observation£»¡¡he¡¡devised¡¡an¡¡experiment¡¡to¡¡determine¡¡the¡¡nature¡¡of¡¡this¡¡acid¡£¡¡He¡¡constructed¡¡an¡¡apparatus¡¡whereby¡¡an¡¡electric¡¡spark¡¡was¡¡passed¡¡through¡¡a¡¡vessel¡¡containing¡¡common¡¡air¡£¡¡¡¡After¡¡this¡¡process¡¡had¡¡been¡¡carried¡¡on¡¡for¡¡several¡¡weeks¡¡a¡¡small¡¡amount¡¡of¡¡liquid¡¡was¡¡formed¡£¡¡This¡¡liquid¡¡combined¡¡with¡¡a¡¡solution¡¡of¡¡potash¡¡to¡¡form¡¡common¡¡nitre£»¡¡which¡¡¡¨detonated¡¡with¡¡charcoal£»¡¡sparkled¡¡when¡¡paper¡¡impregnated¡¡with¡¡it¡¡was¡¡burned£»¡¡and¡¡gave¡¡out¡¡nitrous¡¡fumes¡¡when¡¡sulphuric¡¡acid¡¡was¡¡poured¡¡on¡¡it¡£¡¨¡¡¡¡In¡¡other¡¡words£»¡¡the¡¡liquid¡¡was¡¡shown¡¡to¡¡be¡¡nitric¡¡acid¡£¡¡Now£»¡¡since¡¡nothing¡¡but¡¡pure¡¡air¡¡had¡¡been¡¡used¡¡in¡¡the¡¡initial¡¡experiment£»¡¡and¡¡since¡¡air¡¡is¡¡composed¡¡of¡¡nitrogen¡¡and¡¡oxygen£»¡¡there¡¡seemed¡¡no¡¡room¡¡to¡¡doubt¡¡that¡¡nitric¡¡acid¡¡is¡¡a¡¡combination¡¡of¡¡nitrogen¡¡and¡¡oxygen¡£

This¡¡discovery¡¡of¡¡the¡¡nature¡¡of¡¡nitric¡¡acid¡¡seems¡¡to¡¡have¡¡been¡¡about¡¡the¡¡last¡¡work¡¡of¡¡importance¡¡that¡¡Cavendish¡¡did¡¡in¡¡the¡¡field¡¡of¡¡chemistry£»¡¡although¡¡almost¡¡to¡¡the¡¡hour¡¡of¡¡his¡¡death¡¡he¡¡was¡¡constantly¡¡occupied¡¡with¡¡scientific¡¡observations¡£¡¡¡¡Even¡¡in¡¡the¡¡last¡¡moments¡¡of¡¡his¡¡life¡¡this¡¡habit¡¡asserted¡¡itself£»¡¡according¡¡to¡¡Lord¡¡Brougham¡£¡¡¡¡¡¨He¡¡died¡¡on¡¡March¡¡10£»¡¡1810£»¡¡after¡¡a¡¡short¡¡illness£»¡¡probably¡¡the¡¡first£»¡¡as¡¡well¡¡as¡¡the¡¡last£»¡¡which¡¡he¡¡ever¡¡suffered¡£¡¡His¡¡habit¡¡of¡¡curious¡¡observation¡¡continued¡¡to¡¡the¡¡end¡£¡¡He¡¡was¡¡desirous¡¡of¡¡marking¡¡the¡¡progress¡¡of¡¡the¡¡disease¡¡and¡¡the¡¡gradual¡¡extinction¡¡of¡¡the¡¡vital¡¡powers¡£¡¡¡¡With¡¡these¡¡ends¡¡in¡¡view£»¡¡that¡¡he¡¡might¡¡not¡¡be¡¡disturbed£»¡¡he¡¡desired¡¡to¡¡be¡¡left¡¡alone¡£¡¡His¡¡servant£»¡¡returning¡¡sooner¡¡than¡¡he¡¡had¡¡wished£»¡¡was¡¡ordered¡¡again¡¡to¡¡leave¡¡the¡¡chamber¡¡of¡¡death£»¡¡and¡¡when¡¡be¡¡came¡¡back¡¡a¡¡second¡¡time¡¡he¡¡found¡¡his¡¡master¡¡had¡¡expired¡££§3£§


JOSEPH¡¡PRIESTLEY

While¡¡the¡¡opulent¡¡but¡¡diffident¡¡Cavendish¡¡was¡¡making¡¡his¡¡important¡¡discoveries£»¡¡another¡¡Englishman£»¡¡a¡¡poor¡¡country¡¡preacher¡¡named¡¡Joseph¡¡Priestley¡¡£¨1733¡­1804£©¡¡was¡¡not¡¡only¡¡rivalling¡¡him£»¡¡but£»¡¡if¡¡anything£»¡¡outstripping¡¡him¡¡in¡¡the¡¡pursuit¡¡of¡¡chemical¡¡discoveries¡£¡¡In¡¡1761¡¡this¡¡young¡¡minister¡¡was¡¡given¡¡a¡¡position¡¡as¡¡tutor¡¡in¡¡a¡¡nonconformist¡¡academy¡¡at¡¡Warrington£»¡¡and¡¡here£»¡¡for¡¡six¡¡years£»¡¡he¡¡was¡¡able¡¡to¡¡pursue¡¡his¡¡studies¡¡in¡¡c

·µ»ØĿ¼ ÉÏÒ»Ò³ ÏÂÒ»Ò³ »Øµ½¶¥²¿ ÔÞ£¨0£© ²È£¨0£©

Äã¿ÉÄÜϲ»¶µÄ