Piricacid
Nitroglycerin
DanaExplosive
SmokelessGunpowder
Raymercury
Nitrocellulose
TNT
DoubleBaseExplosive
Hexogen
Expand
History
GunpowderisusedtokillThepoweranddeterrencethatbringmankindhastheeffectofstoppingwarsanddefendingsecurityhavebecomeoneoftheimportantinventionsofhumancivilization.
Accordingtotherecordsof"FanZiJiran",ChinahasbeenusedforcivilianlivelihoodapplicationsintheSpringandAutumnPeriod.FanZiJiransaidthat"nitratecomesoutoftheLongRoad"[23].Thefirstbookinourcountrytorecordtheformulaofgunpowderwaswrittenintheeighthandninethcenturies.Thebooksaysthat"burningwithsulphurandrealgar,saltpeter,andhoney"willcause"flameup,burnhandsandburnoutthehouse"phenomenon.The"secret"hereshouldbethe"honey"ofhoney.Honeycanbecomecharcoalwhenheated.Sulfur,saltpeterandcharcoalaremixed,thisistheformulaofgunpowder.
Theinventionofgunpowderistheresultofpeople'slong-termalchemyandpharmaceuticalpractice.Ithasahistoryofmorethanathousandyears.
InthelastyearsoftheTangDynasty,gunpowderhasbeenusedinthemilitary.InthefirstyearofTangZhaozong'sTianyou(904),YangXingmi'sarmybesiegedYuzhang,andthegeneralZheng(usinghistroopstoflyfire,burnthedragonsandgate,andleadtheheroestoenterthecityfirst,scorchingthecovers).The(flyingfire)mentionedhereis(artillery),(rocket)andthelike.(Artillery)Thegunpowderismadeintoaring,thehangingwireisignited,andthenthrownoutwithastonethrower;therocketisthegunpowderballtiedunderthearrowhead,theleadisignited,andthenshotwithabow.IntheSongDynasty,warscontinuedoneafteranother,whichpromotedtheaccelerateddevelopmentofgunpowderweapons.TheNorthernSongDynastygovernmentestablishedgunpowderworkshops,andsuccessivelyproducedgunpowderarrows,artilleryandotherweaponswithcombustionperformanceaswellasexplosiveweaponssuchasThunderboltandThunder.IntheSouthernSongDynasty,in1259,agiantbamboowascreatedwithgunpowderinside.IntheYuanDynasty,thecoppercastfiresystemappearedagain,called(BronzeGeneral).Theseareallweaponsdrivenbytheexplosionofgunpowder,andtheyhaveshownunprecedentedpowerinthewar.ThepicturebelowshowstheNanweiTumusketandBeiweigunpowderarrow.
Inthe12thand13thcenturies,gunpowderwasfirstintroducedintoArabcountries,andthenspreadtoGreece,Europeandeventherestoftheworld.Ithaspromotedthecivilizationandprogressofhumansocietyandthedevelopmentofeconomy,scienceandculture.TheBritishandFrenchcountriesdidnothaverecordsoftheuseofgunpowderandfirearmsuntilthemiddleofthefourteenthcentury.
1.Originatedfromalchemy
Alchemyoriginatedveryearly.ThereisarecordofalchemistsofferingimmortalmedicinetoKingJinginthe"WarringStatesPolicy".EmperorWuoftheHanalsowantedto"seeforalongtime",solicitedmedicinesfromthepeople,recruitedalchemists,andmadealchemyhimself.Fromthenon,alchemybecameatrendandbegantoprevail.Alchemists,so-calledalchemists,haveappearedthroughouttheages.Thepurposeofthealchemististofindthemedicineforimmortality.Suchagoalisimpossibletoachieve.Alchemyhasbeenpopularformorethanathousandyears,butintheendtherewasnothing.However,somespecificmethodsusedinalchemystillhavemerits,whichshowtheprimitiveformofchemistry.
Averyimportantmethodinalchemyis"firealchemy".Itisdirectlyrelatedtotheinventionofgunpowder.Theso-called"firealchemy"isaboutananhydrousheatingmethod.GeHongoftheJinDynastywroteaboutthefiremethodin"Baopuzi".Materialheating),moxibustion(partialbaking),melting(melting),pumping(distillation),flying(alsocalledascending,whichissublimation),andexcellent(heatingtodenaturethesubstance).Thesemethodsarethemostbasicchemicalmethods,andthisisalsothebasisforthecreationofinventionsinthesillyprofessionofalchemy.Thepietyofthealchemistandthefrustrationofsearchingfortheelixiroflifemakethealchemisthavetorepeatedlyexperimentandfindnewmethods.Thiscreatedconditionsfortheinventionofgunpowder.Beforegunpowderwasinvented,alchemyhadalreadyproducedsomeman-madechemicals,suchasmercurysulfide.Thismaybeoneoftheearliestproductsmadebychemicalsynthesis.
Alchemycaughtfire,whichinspiredpeopletorecognizeandinventgunpowder.
2.Theinventionofgunpowder
Althoughalchemistshavemasteredcertainchemicalmethods,theirdirectionistoseektheelixiroflife,sogunpowderInventionhasacertaincontingency.
Alchemistsoftenusecauterizingmethodsto"volume"beforeusingsulfurandarsenic,whicharehighlytoxic."Volume"meanstosubdue.Toloseorreducetoxicity,thisprocedureiscalled"Fuhuo".SunSimiao,afamousdoctorandalchemistintheearlyTangDynasty,wroteinthe"SulfurMethodintheAlchemySutra":sulfurandsaltpeterweremadeintopowderandplacedinasilverpotorsandjar.Digapit,placethepotinthepitandleveltheground,andfillitwithsoilonallsides.Thethreesoapsthathavenotbeeneatenbyinsectsarecompetedonebyone,andthentheyareputintothepot,andthesulfurandsaltpeteraresetonfireworks.Whenthefireworkscannolongerbeburned,stir-frywithcharcoal,andstir-fryuntilonethirdofthecharcoaliseliminated,thenanneal,takethemixtureinwhileitisstillcold,andlettheflamesgodown.
InthemiddleoftheTangDynasty,therewasamannamedQingxuzi,whoproposedaformulafortheflamesinthe"FuhuoAlumMethod":"Sulfurtwoliang,nitratetwoliang,aristolochthreeandahalfdollars..Therightistheend,mixwell.Digthehole,putthemedicineinthejarandleveltheground.Putapieceofcookedfire,themarbleisbig,putitinside,andthesmokegraduallyrises.”HereplacedthesaponariainSunSimiao’sprescriptionwitharistolochia.Thiskindofsubstancereplacescarbontoplayaburningrole.
Therecipesforburningfireallcontaincarbon,andsulfitemustbeaddedwithsaltpeter,andsulfitemustbeaddedwithsulfur.Thisshowsthatthealchemistdeliberatelywantstocausethemedicinetoburninordertogetridoftheirseverepoison.
Althoughalchemistsknowthatsulphur,nitrate,andcarbonmixedignitionwillcauseaviolentreactionandtakemeasurestocontrolthereactionspeed,butfireaccidentsinthedanfangcausedbytheabusingofdrugshaveoccurredfromtimetotime.Thereisastoryin"TaipingGuangJi".ItisaboutamannamedDuChunziwhovisitedanoldmanalchemyintheearlyyearsoftheSuiDynasty.Stayedtherethatnight.Inthemiddleofthenight,DuChunziwokeupfromhisdreamandsaw"purplesmokepassingthroughthehouse"inthealchemyfurnace,andthehousesuddenlyburned.Thismaybecausedbythenegligenceofthealchemistwhenpreparingflammabledrugs.Thereisalsoanalchemybookcalled"TheSynopsisoftheTrueEssenceandMiaoDao",whichalsotalkedabouttheuseofsulfur,saltpeter,realgarandhoneytomakealchemy.Thefireburnedpeople'sfacesandhands,andevenwentstraighttotheroofandburnedthehouse.NS.Thebookwarnsalchemiststopreventsuchaccidentsfromhappening.ThisshowsthatthealchemistsintheTangDynastyhavealreadymasteredaveryimportantexperience,thatis,sulfur,nitrate,andcarboncanformakindofextremelyflammablemedicine.Thismedicineiscalled"fire-burningmedicine",thatis,gunpowder.Sincetheinventionofgunpowdercamefromtheprocessofmakingalchemy,aftertheinventionofgunpowder,itwasonceregardedasakindofmedicine."CompendiumofMateriaMedica"mentionsthatgunpowdercancuresoresandringworms,killinsects,preventmoisture,andplague.
Gunpowdercannotsolvetheproblemofimmortality,anditiseasytocatchfire.Alchemistsarenotinterestedinit.Theformulaofgunpowderwastransferredfromalchemiststomilitarystrategists,anditbecameoneofthefourgreatinventionsofancientChina.
3.Theapplicationofgunpowder
ThegunpowderintheTangDynasty
Beforetheinventionofgunpowder,fireattackwasAnoffensivemethodcommonlyusedbymilitaryexperts.Atthattime,inthefireattack,aweaponcalledarocketwasused.Ittiedsomeflammablesubstancessuchasgrease,rosin,andsulfurtothearrow,andthenfireditwithabow.Goouttoburndowntheenemy'sposition.Ifgunpowderisusedinsteadofgeneralcombustibles,theeffectismuchbetter.Beforegunpowderwasinvented,astonethrowerwasusedtothrowstonesandgreasefireballstodestroytheenemy.Aftertheinventionofgunpowder,astonethrowerwasusedtothrowgunpowderbagsinsteadofstoneandgreasefireballs.AccordingtotherecordsofLuZhen's"NineKingdoms"intheSongDynasty,duringEmperorAioftheTangDynasty(10thcentury),ZhengWangfanledanarmytoattackYuzhang(nowNanchang,Jiangxi),"startingfire"andburningdowntheLongshaGateofthecity.Thismaybetheearliestrecordofusinggunpowdertosiegeacity.
ThegunpowderintheSongDynasty
IntheSongDynasty,gunpowderweaponsdevelopedrapidly.Accordingtothe"SongHistory·Bingji"record:In970AD,theMinistryofWarorderedShiFengJishengtoentertherocketmethod.Shootout,thisistheworld'searliestjetfirearm.In1000AD,TangFu,asoldier-borncaptainofthegodsandguards,presentedfirearmssuchasrockets,fireballs,andtribulusmadebyhimtotheSongcourt.In1002,ShiPu,theJizhouregimentaltrainer,alsomaderockets,fireballsandotherfirearmsandperformedperformances.
Theappearanceofgunpowderweaponsonthebattlefieldheraldedaseriesofchangesinmilitaryhistory.Transitionfromthephaseofusingcoldweaponstothephaseofusingfirearms.Theinitialformofgunpowderusedinweaponsmainlyusedtheburningpropertiesofgunpowder.Theearlygunpowderweaponsrecordedin"WuJingZongYao"havenotyetdepartedfromthescopeoftraditionalarsonweaponsinfireattacks.Withthedevelopmentofgunpowderandgunpowderweapons,theexplosivepropertiesofgunpowderaregraduallyused.
Thegunpowdermadebymixingpotassiumnitrate,sulfur,andcharcoalpowderiscalledblackgunpowderorbrowngunpowder.Thismixtureisveryeasytoburn,anditburnsquitefiercely.Ifgunpowderburnsinaclosedcontainer,itwillexplode.Whenthegunpowderburns,itcanproducealargeamountofgas(nitrogen,carbondioxide)andheat.Theoriginalsolidgunpowderwithasmallvolumesuddenlyexpandedandincreasedtoseveralthousandtimes.Atthistime,thecontainerwouldexplode.Thisistheexplosivepropertiesofgunpowder.Variousfirearmscanbemanufacturedbyusingtheburningandexplosivepropertiesofgunpowder.ThegunpowderweaponsusedintheNorthernSongDynastywithdifferentpurposeswereallmanufacturedusingtheprincipleofburningandexplodingblackpowder.Tribulusfireballsandpoisonsmokeballsarefirearmswithrelativelylowexplosivepower.AttheendoftheNorthernSongDynasty,the"Thunderbolt"and"Sky-shakingThunder"firearmswithrelativelylargeexplosivepoweralsoappeared.Thistypeoffirearmismainlyusedtoattackfortificationsordefendthecity.In1126AD,whenLiGangshouKaifeng,heusedthunderboltartillerytorepelthesiegeofJinbing.ThewarbetweentheJinandtheNorthernSongDynastyfurtherimprovedtheartillery.TheShakingThunderisanironfirearm,anexplosiveweaponoftheironshelltype.TheYuanarmyusedthisweaponwhentheJinsoldiersdefendedthecitywhentheyattackedJin'sNanjing(nowKaifeng,Henan)."GoldenHistory"hasthisdescriptionofZhentianlei:"Thegunpowderbrokeout,thesoundwaslikethunder,theheatreachedhalfanacre,thehumanandthecowhidewerebrokenandtherewasnotrace,andthearmorandironwereallthrough."Thisdescriptionmaybeabitexaggerated,butitisatrueportrayalofthepowerofgunpowder.
Thedevelopmentoffirearmsdependsontheresearchandproductionofgunpowder.Threegunpowderformulasarerecordedin"WuJingZongYao".ThecontentofsulfurandnitrateinthegunpowderoftheTangDynastywasthesame,1:1,and1:2intheSongDynasty,evencloseto1:3.Itissimilartotheformulaofthree-quartersofnitrateintheblackpowderoflatergenerations.Asmallamountofauxiliaryingredientsareaddedtothegunpowdertoachievetheeffectsofflammability,explosiveness,poisoningandsmokescreenproduction.Gunpowderiscontinuouslyimprovedanddevelopedintheprocessofmanufacturinganduse.
In1044,ZengGongliang's"WuJingZongYao"bookintroducedthreekindsofgunpowderformulas,withdifferentauxiliarymaterials,toachievedifferentpurposesofflammability,explosiveness,poisoningandmakingsmokescreens.
DuetocontinuouswarsintheSongDynasty,thedemandforfirearmsincreaseddaybyday.DuringtheSongShenzongperiod,amilitaryweaponsupervisorwassetuptotakechargeofthenation'smilitarymanufacturing.Themilitaryequipmentsupervisoremploysmorethan40,000workers,andthesupervisionisdividedintotenworkshops.Theproductionofgunpowderandgunpowderweaponsareeachworkshop,andtheyoccupyaveryimportantposition.Thehistorybooksrecordedthescaleofproductionatthattime:"Onthesameday,7,000crossbowgunpowderarrows,10,000bowgunpowderarrows,3,000tribuluscannons,and20,000skinartilleryguns."Thesehavepromotedthedevelopmentofgunpowderandgunpowderweapons.
TubefirearmsappearedintheSouthernSongDynasty,andin1132ADtheconventionalfirearmwasinvented.Themusketismadeoflongbamboopoles.Thegunpowderisplacedinthebamboopolefirst,andthegunpowderislitandsprayedtotheenemyduringcombat.WhenChenGuishouAndeused"morethan20longbamboopolemuskets".In1259AD,somepeopleintheShouchunareamadeaflintlockgun.Theflintlockgunwasmadeofathickbambootube.Thistubularfirearmwasdifferentfromafirearminthattheguncouldonlyshootflamestoburnpeople,andtheflintlockguncontaineda"sub-nest".,Afterthegunpowderisignited,astronggaspressureisgeneratedtoshootthe"childnest"out.The"zinest"istheoriginalbullet.Theflareguncreatedtheforerunneroftubularfirearmstofireprojectiles.Moderngunsweregraduallydevelopedfromtubularfirearms.Therefore,theinventionoftubularfirearmsisanothergreatleapinthehistoryofweapons.
Theblastinggunisalsocalledtheblastingtube,maybeitismadeofbambootubeandgotthisname.Itismentionedinthebook"InstructionsforMarching"quotedin"YongleDadian"thatintheSongDynasty,whendefendingthecity,atorchwasusedtokillandwoundtheenemywhoclimbedtothetopofthecity.AtthetimeofYuanandMingDynasties,thisprimitivetubularfirearmmadeofbambootubewaschangedtocopperorironandcastintoacannon,whichwascalled"firegun".
Thebronzefirecrackerfrom1332istheearliestsurvivinginscribedtubularfirearmintheworld.
MingDynasty
IntheMingDynasty,inthefieldofcombatfirearms,avarietyof"multi-shotrockets"wereinvented,suchasthe"FireCrossbowMeteorArrow"thatfired10arrowsatthesametime.;"Aswarmofbees"thatcanlaunch32arrows;"Ahundredtigersrunalongwitharrows"thatcanlaunchupto100arrows,etc.MingyanKingZhuDi(laterMingChengzu)foughtwithEmperorJianwenatBaigouhe,andheused"aswarmofbees".Thisistheworld'searliestmulti-firerocket,anditcanbecalledtheoriginatorofmodernmultiplerocketlaunchers.Itisespeciallyworthmentioningthatafirearmcalled"firedragonoutofwater"wasusedinwaterbattlesatthattime.Accordingto"WuBeiZhi"records,thisfirearmcanflythreeorfourfeetabovethewater,asfarastwoorthreemiles.Thiskindofrocketismadeofbambooandwood.Fourbig"fires"areattachedtothedragon-shapedshell,andseveralsmallrocketsarehiddeninthebelly.Afterthebig"fires"areignited,theypropelthearrowstofly,"likeafiredragonoutofthewater."Afterthegunpowderburnedout,heignitedasmallrocketinhisabdomenandshotitfromLongkou.Hittingthetargetwillcausetheenemyto"burnpeopleandships."Thisistheworld'sfirstsecond-levelrocket.Inaddition,thebookalsorecordsprototypemissilessuchas"ShenhuoFlyingCrow"thathavecertainexplosiveandburningproperties.The"ShenhuoFlyingCrow"isgluedintoacrowshapewiththinbamboostripsandcottonpaper.Itisfilledwithgunpowderandispropelledbyfourrockets.Itistheworld'searliestmulti-powder-canisterrocketinparallel.Itworksverywellwithtoday'slargebundledcarrierrockets.similar.
Thedevelopmentofrocketshasgivenrisetothedesiretousethethrustofrocketstoflyintothesky.Accordingtohistoricalrecords,attheendofthe14thcentury,abravemanfromtheMingDynastyWanhusatonachairequippedwith47ofthelargestrocketsatthetime,holdingalargekiteineachhand,tryingtousethethrustoftherocketandTheliftofthekiterealizesthedreamofflying.Althoughthiswasafailedattempt,WanHuwashailedasthefirstpersontoflywitharocket.TocommemorateWanhu,aringmountainonthemoonisnamedafterWanhu.
Theimpactofgunpowderonhumans
AccordingtoLuZhen’s"NineKingdoms"intheSongDynasty,duringtheEmperorAiofTangDynasty(10thcentury),ZhengWangfanledthearmyAttackedYuzhang(nowNanchang,Jiangxi),"startedtoflyintofire"andburneddowntheLongshaGateofthecity.Thismaybetheearliestrecordofusinggunpowdertosiegeacity.DuringtheSongDynasty,gunpowderweaponsdevelopedrapidly.Accordingtothe"SongHistory·Bingji"record:In970AD,theMinistryofWarorderedShiFengJishengtoentertherocketmethod.Shootout,thisistheworld'searliestjetfirearm.In1000AD,TangFu,asoldier-borncaptainofthegodsandguards,presentedfirearmssuchasrockets,fireballs,andtribulusmadebyhimtotheSongcourt.In1002,ShiPu,theJizhouregimentaltrainer,alsomaderockets,fireballsandotherfirearmsandperformedperformances.Theappearanceofgunpowderweaponsonthebattlefieldheraldedaseriesofchangesinmilitaryhistory.Transitionfromthephaseofusingcoldweaponstothephaseofusingfirearms.
Theinitialformofgunpowderusedinweaponsismainlytousetheburningpropertiesofgunpowder.Withthedevelopmentofgunpowderandgunpowderweapons,theexplosivepropertiesofgunpowderaregraduallyused.Whenthegunpowderburns,itcanproducealotofgasandheat.Theoriginalsolidgunpowderwithasmallvolumesuddenlyexpandedandincreasedtoseveralthousandtimes.Atthistime,thecontainerwouldexplode.Thisistheexplosivepropertiesofgunpowder.Variousfirearmscanbemanufacturedbyusingtheburningandexplosivepropertiesofgunpowder.ThegunpowderweaponsusedintheNorthernSongDynastywithdifferentpurposeswereallmanufacturedusingtheprincipleofburningandexplodingblackpowder.Tribulusfireballsandpoisonsmokeballsarefirearmswithrelativelylowexplosivepower.AttheendoftheNorthernSongDynasty,the"Thunderbolt"and"Sky-shakingThunder"firearmswithrelativelylargeexplosivepoweralsoappeared.Thistypeoffirearmismainlyusedtoattackfortificationsordefendthecity.In1126AD,whenLiGangshouKaifeng,heusedthunderboltartillerytorepelthesiegeofJinbing.ThewarbetweentheJinandtheNorthernSongDynastyfurtherimprovedtheartillery.TheShakingThunderisanironfirearm,anexplosiveweaponoftheironshelltype.TheYuanarmyusedthisweaponwhentheJinsoldiersdefendedthecitywhentheyattackedJin'sNanjing(nowKaifeng,Henan).TubularfirearmsappearedintheSouthernSongDynasty,andin1132ADtheconventionalfirearmwasinvented.Themusketismadeoflongbamboopoles.Thegunpowderisplacedinthebamboopolefirst,andthegunpowderislitandsprayedtotheenemyduringcombat.WhenChenGuishouAndeused"morethan20longbamboopolemuskets".In1259AD,somepeopleintheShouchunareamadeaflintlockgun.Theflintlockgunwasmadeofathickbambootube.Thistubularfirearmwasdifferentfromafirearminthattheguncouldonlyshootflamestoburnpeople,andtheflintlockguncontaineda"sub-nest".,Afterthegunpowderisignited,astronggaspressureisgeneratedtoshootthe"childnest"out.The"zinest"istheoriginalbullet.Theflareguncreatedtheforerunneroftubularfirearmstofireprojectiles.Moderngunsweregraduallydevelopedfromtubularfirearms.Therefore,theinventionoftubularfirearmsisanothergreatleapinthehistoryofweapons.Theblastinggunisalsocalledtheblastingtube,maybeitismadeofbambootubeandgotthisname..Itismentionedinthebook"InstructionsforMarching"quotedin"YongleDadian"thatintheSongDynasty,whendefendingthecity,atorchwasusedtokillandwoundtheenemywhoclimbedtothetopofthecity.
AtthetimeofYuanandMingDynasties,thisprimitivetubularfirearmmadeofbambootubewaschangedtocopperorironandcastintoacannon,whichwascalled"firegun".IntheMingDynasty,manykindsof"multiplerockets"wereinventedincombatfirearms,suchasthe"FireCrossbowMeteorArrow"thatfired10arrowsatthesametime;the"SwarmofBees"thatfired32arrows;Arrow"andsoon.MingyanKingZhuDi(laterMingChengzu)foughtwithEmperorJianwenatBaigouhe,andheused"aswarmofbees".Thisistheworld'searliestmulti-firerocket,anditcanbecalledtheoriginatorofmodernmultiplerocketlaunchers.Itisespeciallyworthmentioningthatafirearmcalled"firedragonoutofwater"wasusedinwaterbattlesatthattime.Accordingto"WuBeiZhi"records,thisfirearmcanflythreeorfourfeetabovethewater,asfarastwoorthreemiles.Thiskindofrocketismadeofbambooandwood.Fourbig"fires"areattachedtothedragon-shapedshell,andseveralsmallrocketsarehiddeninthebelly.Afterthebig"fires"areignited,theypropelthearrowstofly,"likeafiredragonoutofthewater."Afterthegunpowderburnedout,heignitedasmallrocketinhisabdomenandshotitfromLongkou.Hittingthetargetwillcausetheenemyto"burnpeopleandships."Thisistheworld'sfirstsecond-levelrocket.Inaddition,thebookalsorecordsprototypemissilessuchas"ShenhuoFlyingCrow"thathavecertainexplosiveandburningproperties.The"ShenhuoFlyingCrow"isgluedintoacrowshapewiththinbamboostripsandcottonpaper.Itisfilledwithgunpowderandispropelledbyfourrockets.Itistheworld'searliestmulti-powder-canisterrocketinparallel.Itworksverywellwithtoday'slargebundledcarrierrockets.similar.
Thedevelopmentofrocketshasgivenrisetothedesiretousethethrustofrocketstoflyintothesky.Accordingtohistoricalrecords,attheendofthe14thcentury,abravemanfromtheMingDynasty,WanHu,satonachairequippedwith47ofthelargestrocketsatthetime,holdingalargekiteineachhand,tryingtousethethrustoftherocketandtheliftofthekitetoachieveflight.dream.Althoughthiswasafailedattempt,WanHuwashailedasthefirstpersontoflywitharocket.TocommemorateWanhu,aringmountainonthemoonisnamedafterWanhu.
Asearlyastheeighthandninthcenturies,alongwiththeknowledgeofmedicineandalchemy,nitratealsospreadfromChinatoArabia.TheArabsatthattimecalledit"ChineseSnow",whilethePersianscalledit"ChineseSalt".Theyonlyknowthatnitrateisusedtocurediseases,metallurgyandmakeglass.Inthe13thcentury,gunpowderwasintroducedintoArabcountriesbymerchantsviaIndia.TheGreekslearnedaboutgunpowderonlybytranslatingArabbooks.GunpowderweaponswerespreadtoArabcountriesthroughwars.GenghisKhanfoughtwest,andtheMongolianarmyusedgunpowderweapons.In1260AD,YuanShizu’sarmywasdefeatedinthebattleagainstSyria.TheArabsseizedgunpowderweaponssuchasrockets,poisonedcups,artillery,andsky-shakingthunder,soastomasterthemanufactureanduseofgunpowderweapons.TheArabsfoughtlong-termwarswithsomeEuropeancountries.Duringthewar,theArabsusedgunpowderweapons.Forexample,theArabsusedgunpowderweaponswhentheyattackedtheSpanishcityofPasha.InthewarwithArabcountries,Europeansgraduallymasteredthetechnologyofmakinggunpowderandgunpowderweapons.TheintroductionofgunpowderandgunpowderweaponsintoEurope"notonlychangedthemethodofwarfare,butalsothepoliticalrelationshipbetweenruleandslavery.""Thestonewallsofthecastlesofthenoblesthathadbeenunbreakablebeforecouldnotwithstandthecannonsofthecitizens,andthebulletsofthecitizenspiercedthearmoroftheknights.Theruleofthenoblesdiedwiththenoblecavalryinarmor.Withthedevelopmentofcapitalism,newEliteartillerywasmanufacturedinEuropeanfactories,equippedwithpowerfulfleets,setsailtoconquernewcolonies..."
Chinesegunpowderpromotedtheprocessofworldhistory.EngelsoncespokehighlyofChina’sfirstcreativeuseintheinventionofgunpowder:"IthasnowbeenunquestionablyconfirmedthatgunpowderwaspassedfromChinatotheArabsthroughIndia,andtheArabsandgunpowderweaponspassedthroughSpaintoEurope."TheinventionofgunpowdergreatlypromotedtheprocessofhistoricaldevelopmentandwasoneoftheimportantpillarsoftheEuropeanRenaissance.
4.Historyofexternalcommunication
Asearlyastheeighthandninthcenturies,alongwiththeknowledgeofmedicineandalchemy,nitratewasalsospreadfromChinatoArabia.TheArabsatthattimecalledit"ChineseSnow",whilethePersianscalledit"ChineseSalt".Theyonlyknowthatnitrateisusedtocurediseases,metallurgyandmakeglass.Inthe13thcentury,gunpowderwasintroducedintoArabcountriesbymerchantsviaIndia.TheGreekslearnedaboutgunpowderonlybytranslatingArabbooks.GunpowderweaponswerespreadtoArabcountriesthroughwars.AftertheMongolianexterminationofgoldin1234,alltheartisansandfirearmscapturedinNongfengandotherplacesweretakenaway,andthegunpowderartisansandfirearmsoftheJinarmywereincorporatedintotheMongolianarmy.Thefollowingyear,theMongolianarmylaunchedthesecondwesternexpedition,andthefirearmsnewlyincorporatedintotheMongolianarmyalsojoinedthearmyontheexpedition.Inthefollowingyears,MongoliantroopsequippedwithfirearmssweptacrosstheplainsofEasternEurope.OnApril9,1241,theMongolarmyfoughtafiercebattlewithacoalitionof30,000PolesandGermansontheWallstadPlaininEasternEurope.
Accordingtothebook"HistoryofPoland"bythePolishhistorianDrugos,theMongolianarmyusedpowerfulfirearmsinthisbattle.ThePolishgunpowderhistorianGeislerhidinamonasterynearthebattlefieldandsecretlydepictedtherocketstyleusedbyMongoliansoldiers.AccordingtoGeisler'sdescription,theMongolsfiredrocketsinbundlesfromakindofwoodentube.Becausethedragonheadispaintedonthewoodenslip,itiscalledthe"Chinesefire-breathingdragon"bythePoles.
AftertheMongolsdestroyedtheArabEmpire,theyestablishedtheIliKhanate.ItquicklybecameanimportanthubforthedisseminationofChinesescientificandtechnologicalknowledgesuchasgunpowdertotheWest.Thelong-termpresenceofMongoliantroopsequippedwithgunpowderweaponsinEuropehasprovidedEuropeanswithopportunitiestopeekintogunpowdertechnology.
In1260AD,thearmyofYuanShizuwasdefeatedinthebattleagainstSyria.TheArabsseizedrockets,poisonouscanisters,artillery,sky-shakingthunderandothergunpowderweapons,thusmasteringthemanufactureanduseofgunpowderweapons.TheArabsfoughtlong-termwarswithsomeEuropeancountries.Duringthewar,theArabsusedgunpowderweapons.Forexample,theArabsusedgunpowderweaponswhentheyattackedtheSpanishcityofPasha.InthewarwithArabcountries,Europeansgraduallymasteredthetechnologyofmakinggunpowderandgunpowderweapons.
TheintroductionofgunpowderandgunpowderweaponsintoEuropenotonlychangedthemethodofwarfareitself,butalsochangedthepoliticalrelationshipbetweenruleandslavery.Thestonewallsofthenoblecastlethathadbeenunbreakablebeforecouldnotwithstandthecitizens'cannons,andthecitizens'bulletspiercedtheknight'sarmor.Theruleofthenobilitywasdestroyedwiththenoblecavalryinarmor.Withthedevelopmentofcapitalism,neweliteartillerywasmanufacturedinEuropeanfactories,equippedwithpowerfulfleets,andsetsailtoconquernewcolonies.
Thesignificanceoftheinventionofgunpowder
Chinesegunpowderpromotedtheprocessofworldhistory.EngelsoncespokehighlyofChina'sroleintheinventionofgunpowder:"IthasnowbeenunquestionablyconfirmedthatgunpowderwaspassedfromChinatotheArabsthroughIndia,andtheArabsandgunpowderweaponspassedthroughSpaintoEurope."ThefeudalruleofWesternEuropewasshaken,andtheknightclass,whichreliedoncoldweaponstoshowoffitsmight,isgraduallydeclining!TheinventionofgunpowdergreatlypromotedtheprocessofhistoricaldevelopmentandwasoneoftheimportantpillarsoftheEuropeanRenaissanceandreligiousreform.
GunpowderInformation
Atypeoflowexplosivevelocity.Agentsthatcancauseburningbysparks,flames,etc.Alargeamountofgasisgeneratedduringcombustion,whichhasablastingeffectorapropellingeffect(makingobjectssuchasprojectilesfiredatacertainspeed).Theearliestapplicationwastheblackgunpowderinventedinmycountry.Theblackgunpowderiscomposedofsulfur,carbon,andnitrate.Accordingtothenatureofburning,gunpowdercanbedividedintotwotypes:pyrotechnicpowder(whichemitssmokewhenburning,suchasblackpowder)andsmokelesspowder.Smokelessgunpowderismainlyusedastheignitionorpropellantofammunition.
GunpowderinChina
GunpowderwasinventedbytheChinese,andithasbeenmorethanathousandyearsago.Theresearchofgunpowderbeganwithancientalchemy.
Chinawasthefirstcountrytoinventgunpowder.IntheSuiDynasty,theternarysystemofsaltpeter,sulfurandcharcoalwasborn.BlackgunpowderofficiallyappearedintheTangDynasty(theendofthe9thcentury).Gunpowderwasinventedbyancientalchemists.FromtheWarringStatestotheearlyHanDynasty,theemperorsandnobleswereintoxicatedwiththefantasyofbeingimmortalsandimmortal,drivingsomealchemistsandTaoiststorefinethe"Elixir",andgraduallyinventedtheformulaofgunpowderduringtherefiningprocess.InthefirstyearofEmperorYongchunoftheTangDynasty(682),alchemistsintheTangDynastypioneeredthesulfurvoltammetry,whichusedsulfurandsaltpetertogrindintopowder,andthenaddedsaponins(containingcarbon).TangXianzongyuanandthreeyears(808)inventedthefire-rockmethod,usingsaltpeter,sulfurandaristolochia(includingcarbon)tosmelttogether.Thesetwoformulasareamixtureofthreekindsofmedicines,andtheyalreadyhavetheingredientscontainedingunpowder.
Theinitialuseofgunpowderwasnotinthemilitary,butintheacrobaticperformancesofthemilitarycircusintheSongDynasty,aswellasthefireworkandacrobaticsinthepuppetshow-medicinepuppets.IntheSongDynasty,performancessuchas"HoldingtheGong","HardGhost",and"DumbOpera"allusedthenewly-emergedgunpowderproducts"explosivebattle"and"firespitting"tocreateamysteriousatmosphere.Songpeoplealsousedgunpowdertoperformillusions,suchassprayingoutfireworksandcloudstoescapepeopleandchangethings,soastoachievetheeffectofmagicalblur.
Chinainventedgunpowderandfirstusedittomakefireworks,andsoonuseditinthemilitary,andinventedtheworld'sfirstrocket.CannonsandmusketshavebeenquitematureinthemilitaryuseofgunpowderinSongDynasty,makingChina'stechnologyfaraheadoftheworld.
Classification
Classificationofgunpowder
Gunpowderistheenergysourceforweaponstolaunchprojectiles,whichcanbedividedintoignitionpowder,propellant,andsolidpropellantaccordingtotheiruses.Amongthem,thepropellantisdividedinto:gunpropellant,artillerypropellant,ejectionseatpropellant,etc.Solidpropellantsaredividedintosolidpropellantsforrocketsandsolidpropellantsformissiles.
Externalcharacteristics
Accordingtotheexternalcharacteristicsofthegunpowderburning,itcanbedividedintosmokedpowderandsmokelesspowder:accordingtothechangeofthesurfaceareawhenthegunpowderburns,itcanbedividedintoreducedsurfaceburningpowder,Constantsurfaceburninggunpowder,increasedsurfaceburninggunpowder.
Moldingprocess
Accordingtothemoldingprocessofgunpowder,itcanbedividedinto:suppressedgunpowder,castinggunpowder,mixedgunpowder,etc.Accordingtosomecharacteristicsofgunpowder,itcanbedividedintoeasilyvolatilegunpowderandhardlyvolatilegunpowder.
Structure
Themostcommonlyusedgunpowderisdividedintohomogeneousgunpowderandheterogeneousgunpowderaccordingtothestructure.Becauseofthedifferenceinstructure,theprocessproperties,combustionproperties,andphysicalandmechanicalpropertiesareuniform.Thereisasignificantdifference.Homogeneousgunpowderisfurtherdividedinto:single-basemedicine,double-basemedicine,multi-basemedicine,andmodifieddouble-basemedicine.Double-basedrugsarefurtherdividedintoKodak-typedouble-basedrugsandVallestine-typedouble-basedrugs.Heterogeneousgunpowderisdividedintoblackgunpowder,compoundgunpowderandsoon.
Composition
Gunpowderisamixtureofsulfur,saltpeter,charcoal.Longago,ourancestorshadacertainunderstandingofthesethreesubstances.AsearlyastheNeolithicAge,peopleknewcharcoalwhentheymadepotteryanduseditasfuel.DuringtheShangandZhouDynasties,charcoalwaswidelyusedinmetallurgy.Charcoalhaslessashandhigherstrengththanfirewood,andisabetterfuelthanfirewood.Sulfurexistsnaturally,andpeoplehaveexploiteditforalongtime.Sulfurisoftenencounteredinlifeandproduction.Forexample,hotspringswillreleasethescentofsulfur.Whenmetalissmelted,thesulphurdioxidethatescapesispungentandunpleasant.Thesewillleaveanimpressiononpeople.Theearliestknownsaltpetrebytheancientsmaybethesoilsaltpetreinthecornersandundertherootsofthehouse.Thechemicalpropertiesofsaltpetreareveryactiveandcanreactwithmanysubstances.Itscolorisnotmuchdifferentfromothersalts.Itiseasytomakemistakesinuse.InpracticePeopleinChinahavemasteredsomemethodstoidentifysaltpeter.IntheSouthernandNorthernDynasties,TaoHongjing’s"CommentsontheClassicsofPlantsandTrees"said:"Burnitwithfire,thepurplesmokewillrise,andthecloudissaltpeter."Thisissimilartothemodernmethodofidentifyingpotashbyflamereaction(themaincomponentofsaltpeterispotassiumnitrate.).Saltpeterandsulfurwereonceusedasimportantmedicinalmaterials.Inthe"ShenNong'sMateriaMedica"intheHanDynasty,saltpeterwaslistedasthesixthamongthetopgrades,anditwasbelievedtobeabletocuremorethan20diseases.SulfurislistedasthethirdChinesemedicine,anditcanalsocuremorethan10diseases.Inthisway,peoplepaymoreattentiontotheresearchofsaltpeterandsulfur.Althoughpeoplehaveacertainunderstandingofthenatureofsaltpeter,sulfur,andcharcoal,itisstillthemeritofalchemistswhoputsaltpeter,sulfur,andcharcoaltogetherinacertainproportiontomakegunpowder.
Requirementsforuse
Thegunpowdershouldmeetthefollowingrequirements:1.Goodcombustionstabilityandregularity.2.Sufficientstrengthtoensurethatthedrugbodywillnotruptureduringignitionandaffectthecombustionperformance.3.Goodtoughnessandchemicalstabilitytoensurethatthegunpowdercanbestoredforalongtimewithoutdeterioration.4.Mechanicalsensitivitysuchasimpactandfrictionshouldbesmalltoensuresafetyduringuse,production,storage,andtransportation.
Moderngunpowder
Developmenthistory
Moderngunpowderoriginatedin1771.P.WolfeofEnglandsynthesizedpicricacid.Thisisayellowcrystalthatwasoriginallyusedasayellowdye(notethis,itmeansthatitsproductionwasnotaffectedbytheso-called"blackgunpowder",itwasdiscoveredbyaccident,whichisalsotheoriginofthenameoftheyellowgunpowder),andlaterDiscovereditsexplosivefunction,itwaswidelyusedinthemilitaryinthenineteenthcenturytoloadartilleryshells.Itisapowerfulexplosive.
In1779,BritishchemistE.Howardinventedthundermercury,alsoknownasmercuryfulminate.Itisakindofdetonator,usedforpreparingflasherfiringandacupuncture,andalsousedforfillingdetonatorsforblasting.
In1807,theScotsinventedthefirstpropellantmadeofpotassiumchlorate,sulfur,andcarbon.In1838,T.J.Peruzzifirstdiscoveredthatcottoncouldexplodewhenimmersedinnitricacid.In1845,theGermanchemistC.F.Schoenbeinsoakedcottoninamixtureofnitricacidandsulfuricacidtowashawaytheexcessacid,andinventednitrocellulose,namelycollodion.
In1860,themajorofthePrussianarmy,E.Tiertz,usednitrocellulosetomakepropellantforgunsandshells.Commonlyknownascottongunpowder.Sofar,nitrocellulosegunpowderhasreplacedblackgunpowderasthepropellant.
In1846,theItalianchemistA.Sobremadenitroglycerinforthefirsttimebydroppinghalfofglycerinintoamixtureofonepartofnitricacidandtwopartsofconcentratedsulfuricacid.Nitroglycerinisastrongliquidexplosive.Slightvibrationcanexplodeviolently,whichisdangerousandunsuitableforproduction.
In1862,A.B.NobelofSwedendevelopedasafeproductionmethodfortheproductionofnitroglycerinbythe"warmmethod",whichenabledittobeproducedinbatchesinarelativelysafemanner.
In1863,J.WillbrandinventedTNT(TNT).ThechemicalcompositionofTNTistrinitrotoluene,whichisaverypowerfulandverysafeexplosive.Evenifitispenetratedbyabullet,itwillnotburnordetonate.Itbegantobewidelyusedforloadingvariousammunitionandexplosivesintheearly20thcentury,graduallyreplacingpicricacid.
In1866,A.B.NobeluseddiatomaceousearthtoabsorbnitroglycerinandinventedtheDanaexplosive.Commonlyknownasyellowgunpowder.
In1872,Nobeladdednitrocellulosetonitroglycerinandinventedagum-likecolloidalexplosive-colloidalDanaexplosive,whichwastheworld'sfirstdouble-baseexplosive.
In1884,FrenchchemistandengineerP.Vielliinventedsmokelessgunpowder.ThisinventionisofgreatsignificanceandcreatedammunitionconditionsfortheinventionoftheMaximheavymachinegun.Becauserelyingonthepreviouspyrotechnicpowder,toomanyimpuritiesareproduced,whichwillcauseblockageandcannotbeusedformachinegunbulletfiring.Sofar,pyrotechnicpowderhasbeenreplaced,andsmokelesspowderhasbecomeacommonlyusedpropellant.
In1887,Nobelreplacedetherandethanolwithnitroglycerin,andalsomadeasimilarsmokelessgunpowder.HealsoaddedammoniumnitratetoDanaexplosiveinsteadofpartofnitroglycerintomakeasaferandcheaper"specialDanaexplosive",alsoknownas"extra-strongyellowgunpowder."
In1899,theGermanHenninginventedRoxygen,whichisamorepowerfulexplosivethanTNT.Thisisthemostpowerfulexplosiveafternuclearweapons.Fromtheaboveclues,wecanclearlyseehowtheyellowpowdersystemdevelopedindependentlyandledtomajorchangesinmodernmilitaryaffairs.Inthisprocess,blackpowderhasbeengraduallyeliminated.
BlackpowderhasbeenusedforpyrotechnicsandarsoninEuropeforalongtime.Itwasalsousedasapropellantforguns,butitcanonlybeappliedtoprimitivefirearmswithlimitedpowerintheMiddleAges,suchasmuskets.Theblistergunisnotsuitableforuseasabreechrifle,machinegunandothermodernguns.Themedievalfirearmsandmoderngunsarealsocompletelytwoconcepts.Inprinciple,technology,andmanufacturingandprocessingarecomplete.Different,don'tbeconfusedbythesimilaritiesinsomeoftheirappearances.Itspowerisalsolimited.Inmanycases,thecavalrychargeisstillthemainmethodofvictoryinmodernWesternwars.Thissituationwasnotendeduntilthemachinegunwasinvented.Theearlyfront-loadedmusketwasnotmuchmorepowerfulthanthecrossbow,anditwaslong-termCoexistandusewithcrossbows,etc.Weshouldnotbemisledbythoseexaggerateddescriptions.
Theblackpowderusedasapropellantwasbasicallyeliminatedinthe19thcentury.Withtheemergenceofsmokelesspowder,double-basepowder,detonators,TNT,etc.,therealmilitarywasborn.Therevolutionhasbroughtaboutguns,rockets,bombs,andmissilesinourmodernsense.
TheuseofgunpowderinthemilitarybeganinChina:peopleinventedgunpowderandsoonplayeditsroleinthemilitary.Beforetheinventionofgunpowder,ancientmilitarystrategistsusedfireattacktodefeattheenemy.Infireattacks,"rockets"areoftenused,thatis,flammablegrease,rosin,sulfur,etc.areattachedtothearrows,andtheyareignitedandfiredattheenemy.Butbecausethiskindofburningfirepowerissmallandeasytoextinguish,aftertheemergenceofgunpowder,peopleusegunpowdertoreplacetheabove-mentionedcombustibles,andthemaderocketburnsmuchmoreviolently.Sometimespoisonoussubstancessuchascrotonandarsenicareaddedtothegunpowder,andthesmokegeneratedafterburningisscatteredaround,whichisequivalentto"gasbombs."Butthesearejusttheuseoftheburningpropertiesofgunpowder.Withthedevelopmentofgunpowderweapons,itgraduallytransitionedtotheuseoftheexplosivepropertiesofgunpowder.Theso-called"thunderboltartillery"and"sky-shakingthunder"usedtorepelthegoldensoldiersintheNorthernSongDynastyweremadeofironshells.Thestrengthwasmuchgreaterthanthatofpaper,cloth,andleather.Increasetoacertainlevelbeforeexploding,soitispowerfulandlethal.Fromusingtheburningperformanceofgunpowdertousingtheexplosiveperformanceofgunpowder,thistransformationmarksthearrivalofthematurestageoftheuseofgunpowder.
CaiGuoqiangandhisgunpowderlanguageintroduction
CaiGuoqiangwasborninQuanzhouCity,FujianProvince,Chinain1957.GraduatedfromtheStageArtDepartmentofShanghaiTheatreAcademy.Inthemid-1980s,hebegantousegunpowderinventedinChinatocreateworks.From1986to1995,helivedinJapan.Withthedevelopmentofartactivities,large-scaleoutdoorblastingplanswerelaunchedallovertheworld.In1994,CaiGuoqiangparticipatedinthe"CreativityofAsia"exhibitionheldbytheHiroshimaMuseumofContemporaryArt.Withthetitle"TheEarthHasaBlackHole",heproducedalarge-scaleblastingplanintheCentralParkofHiroshimaCity,usinga900-meter-longfuseandgunpowder.,Explodedthedevicefloatingonthebigballoonintheair.
ImovedtoNewYorkin1995andbecamemoreactivearoundtheworld.Inadditiontousinggunpowder,healsointroducedtraditionalChineseculturalmedicineandFengshuiintohisworks,suchastheaudienceparticipationworktitled"CulturalMixture",Isthejointcompletionofinvitingtheaudiencetotakeabathtogether.In1999,hewontheInternationalGoldenLionAwardattheVeniceBiennaleandwashighlypraisedinternationally.In2001,heservedasthechiefdesigneroftheAPEC(AsiaPacificEconomicConference)landscapefireworksheldinShanghai.Heiscurrentlythecorecreativememberandchiefvisualeffectsartdesigneroftheopeningandclosingceremoniesofthe2008BeijingOlympicGames.CaiGuoqiang,withhisuniqueChinesecosmologyandphilosophicalfoundation,explorescommonproblemsofmankind,andhehasattractedmuchattentionasamodernartistwhospeaksfromanAsianperspectivedifferentfromWesternEurope.
Abriefdescriptionofmoderngunpowder
Gunpowderisasubstancethatcancauseself-sustaineddetonationthroughacertainexternalexcitationimpulse.Detonationisanexplosionphenomenonwhenthepropagationspeedofthechemicalreactionzoneintheexplosiveisgreaterthanthespeedofsoundintheexplosive,anditisatypicalformofenergyreleaseoftheexplosive.Becausethechemicalreactionspeedisveryfastwhenexplosivesexplode,hightemperatureandhighpressuregasisformedinaninstant.Withextremelyhighpower(theinstantaneousoutputpowerperkilogramofexplosivedetonationcanreach5×107kilowatts)toworkontheoutsideworld,sothatthesurroundingmediumissubjecttostrongimpact,compressionanddeformationorfragmentation.Explosivescanbeusedinthemilitaryasexplosivechargesforartilleryshells,aerialbombs,missiles,mines,torpedoes,handgrenadesandotherammunition,aswellasnuclearbombdetonatorsandmilitaryblasting.Inindustry,itiswidelyusedinmining,roadconstruction,waterconservancyconstruction,engineeringblasting,metalprocessing,etc.,anditisalsowidelyusedinscientificandtechnologicalfieldssuchasseismicexploration.
Explosivesareoftencalledhighexplosivesbecausetheycandoviolentdamagetothesurroundingmedium.Commonlyusedexplosivescanbedividedinto2typesofsingleexplosivesandmixedexplosivesaccordingtotheircomposition.Thereisalsoaclassofexplosiveswithhighsensitivity.Thetimefromburningtodetonationisveryshort,anditisusuallynotuseddirectlyfordestructivework,butusedtoigniteordetonateotherexplosives,calledinitiatingexplosives.
Theexplosiveperformanceofexplosivesismainlyrepresentedbydetonationheat,detonationvolume,detonationvelocityanddetonationpressure.Explosionheatistheheatreleasedwhenaunitmassexplosiveexplodesundercertainconditions,whichisdeterminedbytheelementcomposition,chemicalstructureandexplosivereactionconditionsoftheexplosive.Itcanbecalculatedbythermochemicalmethodormeasured.Explosionvolumeistheamountofgasproducedwhenaunitmassexplosiveexplodes(indicatedbythevolumeinthestandardstate),generally0.7to1.0m3/kg.Detonationvelocityisthepropagationspeedofdetonationwaves(shockwavesthataccompanychemicalreactions)inexplosives.Thedetonationvelocityofexplosivesatacertainchargedensitycanbeaccuratelymeasured.Existingexplosivesgenerallyhaveadetonationvelocityof1,000to8,500meterspersecond,andrarelyexceed9,000meterspersecond.Detonationpressurereferstothepressureofthedetonationwavefrontwhentheexplosiveexplodes,whichcanbemeasuredindirectlybyexperimentalmethods,anditsvalueisgenerally10-40gigapascals.