ThelastobjectionofMr。Thorntontothereceivedtheory，andtheonethathelaysmoststressupon，is，thatitassumes\"thatgoodsareofferedforsaleunreservedly，andthatdealersarealwayscontenttoletthemgoforwhattheywillfetch。\"This，however，heobserves，——
Isscarcelyever——nay，mightalmostbesaidtobeabsolutelynever——thefact。Withonenotableexception，thatoflabour，commoditiesarealmostneverofferedunreservedlyforsale;scarcelyeverdoesadealerallowhisgoodstogoforwhattheywillimmediatelyfetch——scarcelyeverdoesheagreetothepricewhichwouldresultfromtheactualstateofsupplyanddemand，or，inotherwords，tothepriceatwhichhecouldimmediatelysellthewholeofhisstock。Imaginethesituationofamerchantwhocouldnotaffordtowaitforcustomers，butwasobligedtoacceptforacargoofcorn，orsugar，orsundries，thebestofferhecouldgetfromthecustomerswhofirstpresentedthemselves;orimagineajeweller，orweaver，ordraper，orgrocer，obligedtoclearouthisshopwithintwenty—fourhours。Thenearestapproachevermadetosuchapredicamentisthatofabankrupt’screditorssellingofftheirdebtor’seffectsataproverbially’tremendoussacrifice;’andeventheyare，comparativelyspeaking，abletotaketheirtime。Butthebehaviourofadealerunderordinarypressureisquitedifferentfromthatofabankrupt’sassignees。Hefirstaskshimselfwhatisthebestpricewhichislikelytobepresentlygiven，notforthewhole，butforsomeconsiderableportionofhisstock，andhethenbeginsselling，eitheratthatpriceoratsuchotherpriceasprovesupontrialtobethebestobtainableatthetime。Hissupplyofgoodsisprobablyimmenselygreaterthanthequantitydemandedatthatprice，butdoeshethereforelowerhisterms？Notatall，andhesellsasmuchashecanatthatprice，andthen，havingsatisfiedtheexistingdemand，hewaitsawhileforfurtherdemandtospringup。Inthiswayheeventuallydisposesofhisstockformanytimestheamounthemusthavebeenfaintoacceptifhehadattemptedtoselloffallatonce。Acorndealerwhointhecourseofaseasonsellsthousandsofquartersofwheatatfiftyshillingsperquarter，orthereabouts，wouldnotgettwentyshillingsaquarterif，assoonashiscornshipsarrived，hewasobligedtoturnthecargoesintomoney。Agloverwho，bywaitingforcustomers，willnodoubtgetthreeorfourshillingsapairforalltheglovesinhisshop，mightnotgetsixpenceapairifheforcedthemonhiscustomers。Buthowisitthathemanagestosecurethehigherprice？Simplybynotsellingunreservedly，simplybydecliningthepricewhichwouldhaveresultedfromtherelationsbetweenactualsupplyandactualdemand，andbysettinguphisgoodsatsomehigherprice，belowwhichherefusestosell。（pp。55—6。）
IconfessIcannotperceivethattheseconsiderationsaresubversiveofthelawofdemandandsupply，northatthereisanygroundforsupposingpoliticaleconomiststobeunawarethatwhensupplyexceedsthedemand，thetwomaybeequalisedbysubtractingfromthesupplyaswellasbyaddingtothedemand。Reservingapriceis，toallintentsandpurposes，withdrawingsupply。Whennomorethanfortyshillingsaheadcanbeobtainedforsheep，allsheepwhoseownersaredeterminednottosellthemforlessthanfiftyshillingsareoutofthemarket，andformnopartatallofthesupplywhichisnowdeterminingprice。Theymayhavebeenofferedforsale，buttheyhavebeenwithdrawn。Theyareheldback，waitingforsomefuturetime，whichtheirownerhopesmaybemoreadvantageoustohim;andtheywillbeanelementindeterminingthepricewhenthattimecomes，orwhen，ceasingtoexpectit，orobligedbyhisnecessities，heconsentstosellhissheepforwhathecanget。Inthemeanwhile，thepricehasbeendeterminedwithoutanyreferencetohiswithheldstock，anddeterminedinsuchamannerthatthedemandatthatpriceshall（ifpossible）beequaltothesupplywhichthedealersarewillingtopartwithatthatprice。Theeconomistswhosaythatmarketpriceisdeterminedbydemandandsupplydonotmeanthatitisdeterminedbythewholesupplywhichwouldbeforthcomingatanunattainableprice，anymorethanbythewholedemandthatwouldbecalledforthifthearticlecouldbehadforanoldsong。Theymeanthat，whateverthepriceturnsouttobe，itwillbesuchthatthedemandatthatprice，andthesupplyatthatprice，willbeequaltooneanother。TothispropositionMr。Thorntonshowsanundeniableexceptioninthecaseofadealerwhoholdsoutforapricewhichhecanobtainforapartofhissupply，butcannotobtainforthewhole。Inthatcase，undoubtedly，thepriceobtainedisnotthatatwhichthedemandisequaltothesupply;butthereasonisthesameasinoneofthecasesformerlyconsidered;becausethereisnosuchprice。Attheactualpricethesupplyexceedsthedemand;atafarthinglessthewholesupplywouldbewithheld。Suchacasemighteasilyhappenifthedealerhadnocompetitiontofear;noteasilyifhehad:
butonnosuppositiondoesitcontradictthelaw。ItfallswithintheonecaseinwhichMr。Thorntonhasshownthatthelawisnotfulfilled——namely，whenthereisnopricethatwouldfulfilit;eitherthedemandorthesupplyadvancingorrecedingbysuchviolentskips，thatthereisnohaltingpointatwhichitjustequalstheotherelement。
DoIthenmeantosaythatMr。Thorntonisentirelywronginhisinterpretationofthecaseswhichhesuggests，andhaspointedoutnoimperfectioninthecurrenttheory？Evenifitwereso，itwouldnotfollowthathehasrenderednoservicetoscience。\"Thereisalwaysabenefitdonetoanydepartmentofknowledgebydiggingabouttherootsofitstruths。（4）Scientificlawsalwayscometobebetterunderstoodwhenablethinkersandacutecontroversialistsstirupdifficultiesrespectingthem，andconfrontthemwithfactswhichtheyhadnotyetbeeninvokedtoexplain。ButMr。