a history of science-2-第31章

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　to　understand　how　an　unscrupulous　mediaeval　Hermann　or　Kellar　might　completely　deceive　even　the　most　intelligent　and　thoughtful　scholars。　In　scoffing　at　the　credulity　of　such　an　age；　it　should　not　be　forgotten　that　the　〃Keely　motor〃　was　a　late　nineteenth…century　illusion。　But　long　before　the　belief　in　the　philosopher's　stone　had　died　out；　the　methods　of　the　legerdemain　alchemist　had　been　investigated　and　reported　upon　officially　by　bodies　of　men　appointed　to　make　such　investigations；　although　it　took　several　generations　completely　to　overthrow　a　superstition　that　had　been　handed　down　through　several　thousand　years。　In　April　of　1772　Monsieur　Geoffroy　made　a　report　to　the　Royal　Academy　of　Sciences；　at　Paris；　on　the　alchemic　cheats　principally　of　the　sixteenth　and　seventeenth　centuries。　In　this　report　he　explains　many　of　the　seemingly　marvellous　feats　of　the　unscrupulous　alchemists。　A　very　common　form　of　deception　was　the　use　of　a　double…bottomed　crucible。　A　copper　or　brass　crucible　was　covered　on　the　inside　with　a　layer　of　wax；　cleverly　painted　so　as　to　resemble　the　ordinary　metal。　Between　this　layer　of　wax　and　the　bottom　of　the　crucible；　however；　was　a　layer　of　gold　dust　or　silver。　When　the　alchemist　wished　to　demonstrate　his　power；　he　had　but　to　place　some　mercury　or　whatever　substance　he　chose　in　the　crucible；　heat　it；　throw　in　a　grain　or　two　of　some　mysterious　powder；　pronounce　a　few　equally　mysterious　phrases　to　impress　his　audience；　and；　behold；　a　lump　of　precious　metal　would　be　found　in　the　bottom　of　his　pot。　This　was　the　favorite　method　of　mediocre　performers；　but　was；　of　course；　easily　detected。　An　equally　successful　but　more　difficult　way　was　to　insert　surreptitiously　a　lump　of　metal　into　the　mixture；　using　an　ordinary　crucible。　This　required　great　dexterity；　but　was　facilitated　by　the　use　of　many　mysterious　ceremonies　on　the　part　of　the　operator　while　performing；　just　as　the　modern　vaudeville　performer　diverts　the　attention　of　the　audience　to　his　right　hand　while　his　left　is　engaged　in　the　trick。　Such　ceremonies　were　not　questioned；　for　it　was　the　common　belief　that　the　whole　process　〃lay　in　the　spirit　as　much　as　in　the　substance；〃　many；　as　we　have　seen；　regarding　the　whole　process　as　a　divine　manifestation。　Sometimes　a　hollow　rod　was　used　for　stirring　the　mixture　in　the　crucible；　this　rod　containing　gold　dust；　and　having　the　end　plugged　either　with　wax　or　soft　metal　that　was　easily　melted。　Again；　pieces　of　lead　were　used　which　had　been　plugged　with　lumps　of　gold　carefully　covered　over；　and　a　very　simple　and　impressive　demonstration　was　making　use　of　a　nugget　of　gold　that　had　been　coated　over　with　quicksilver　and　tarnished　so　as　to　resemble　lead　or　some　base　metal。　When　this　was　thrown　into　acid　the　coating　was　removed　by　chemical　action；　leaving　the　shining　metal　in　the　bottom　of　the　vessel。　In　order　to　perform　some　of　these　tricks；　it　is　obvious　that　the　alchemist　must　have　been　well　supplied　with　gold；　as　some　of　them；　when　performing　before　a　royal　audience；　gave　the　products　to　their　visitors。　But　it　was　always　a　paying　investment；　for　once　his　reputation　was　established　the　gold…maker　found　an　endless　variety　of　ways　of　turning　his　alleged　knowledge　to　account；　frequently　amassing　great　wealth。　Some　of　the　cleverest　of　the　charlatans　often　invited　royal　or　other　distinguished　guests　to　bring　with　them　iron　nails　to　be　turned　into　gold　ones。　They　were　transmuted　in　the　alchemist's　crucible　before　the　eyes　of　the　visitors；　the　juggler　adroitly　extracting　the　iron　nail　and　inserting　a　gold　one　without　detection。　It　mattered　little　if　the　converted　gold　nail　differed　in　size　and　shape　from　the　original；　for　this　change　in　shape　could　be　laid　to　the　process　of　transmutation；　and　even　the　very　critical　were　hardly　likely　to　find　fault　with　the　exchange　thus　made。　Furthermore；　it　was　believed　that　gold　possessed　the　property　of　changing　its　bulk　under　certain　conditions；　some　of　the　more　conservative　alchemists　maintaining　that　gold　was　only　increased　in　bulk；　not　necessarily　created；　by　certain　forms　of　the　magic　stone。　Thus　a　very　proficient　operator　was　thought　to　be　able　to　increase　a　grain　of　gold　into　a　pound　of　pure　metal；　while　one　less　expert　could　only　double；　or　possibly　treble；　its　original　weight。　The　actual　number　of　useful　discoveries　resulting　from　the　efforts　of　the　alchemists　is　considerable；　some　of　them　of　incalculable　value。　Roger　Bacon；　who　lived　in　the　thirteenth　century；　while　devoting　much　of　his　time　to　alchemy；　made　such　valuable　discoveries　as　the　theory；　at　least；　of　the　telescope；　and　probably　gunpowder。　Of　this　latter　we　cannot　be　sure　that　the　discovery　was　his　own　and　that　he　had　not　learned　of　it　through　the　source　of　old　manuscripts。　But　it　is　not　impossible　nor　improbable　that　he　may　have　hit　upon　the　mixture　that　makes　the　explosives　while　searching　for　the　philosopher's　stone　in　his　laboratory。　〃Von　Helmont；　in　the　same　pursuit；　discoverd　the　properties　of　gas；〃　says　Mackay；　〃Geber　made　discoveries　in　chemistry；　which　were　equally　important；　and　Paracelsus；　amid　his　perpetual　visions　of　the　transmutation　of　metals；　found　that　mercury　was　a　remedy　for　one　of　the　most　odious　and　excruciating　of　all　the　diseases　that　afflict　humanity。〃'　As　we　shall　see　a　little　farther　on；　alchemy　finally　evolved　into　modern　chemistry；　but　not　until　it　had　passed　through　several　important　transitional　stages。

ASTROLOGY　In　a　general　way　modern　astronomy　may　be　considered　as　the　outgrowth　of　astrology；　just　as　modern　chemistry　is　the　result　of　alchemy。　It　is　quite　possible；　however；　that　astronomy　is　the　older　of　the　two；　but　astrology　must　have　developed　very　shortly　after。　The　primitive　astronomer；　having　acquired　enough　knowledge　from　his　observations　of　the　heavenly　bodies　to　make　correct　predictions；　such　as　the　time　of　the　coming　of　the　new　moon；　would　be　led；　naturally；　to　believe　that　certain　predictions　other　than　purely　astronomical　ones　could　be　made　by　studying　the　heavens。　Even　if　the　astronomer　himself　did　not　believe　this；　some　of　his　superstitious　admirers　would；　for　to　the　unscientific　mind　predictions　of　earthly　events　would　surely　seem　no　more　miraculous　than　correct　predictions　as　to　the　future　movements　of　the　sun；　moon；　and　stars。　When　astronomy　had　reached　a　stage　of　development　so　that　such　things　as　eclipses　could　be　predicted　with　anything　like　accuracy；　the　occult　knowledge　of　the　astronomer　would　be　unquestioned。　Turning　this　apparently　occult　knowledge　to　account　in　a　mercenary　way　would　then　be　the　inevitable　result；　although　it　cannot　be　doubted　that　many　of　the　astrologers；　in　all　ages；　were　sincere　in　their　beliefs。　Later；　as　the　business　of　astrology　became　a　profitable　one；　sincere　astronomers　would　find　it　expedient　to　practise　astrology　as　a　means　of　gaining　a　livelihood。　Such　a　philosopher　as　Kepler　freely　admitted　that　he　practised　astrology　〃to　keep　from　starving；〃　although　he　confessed　no　faith　in　such　predictions。　〃Ye　otherwise　philosophers；〃　he　said；　〃ye　censure　this　daughter　of　astronomy　beyond　her　deserts；　know　ye　not　that　she　must　support　her　mother　by　her　charms。〃　Once　astrology　had　become　an　established　practice；　any　considerable　knowledge　of　astronomy　was