Whenthegreaterpartofthehighlandcattlewereconsumedontheirownhills，theexportationoftheirhidesmadethemostconsiderablearticleofthecommerceofthatcountry，andwhattheywereexchangedforaffordedsomeadditiontotherentofthehighlandestates。ThewoolofEngland，whichinoldtimescouldneitherbeconsumednorwroughtupathome，foundamarketinthethenwealthierandmoreindustriouscountryofFlanders，anditspriceaffordedsomethingtotherentofthelandwhichproducedit。IncountriesnotbettercultivatedthanEnglandwasthen，orthanthehighlandsofScotlandarenow，andwhichhadnoforeigncommerce，thematerialsofclothingwouldevidentlybesosuperabundantthatagreatpartofthemwouldbethrownawayasuseless，andnopartcouldaffordanyrenttothelandlord。
Thematerialsoflodgingcannotalwaysbetransportedtosogreatadistanceasthoseofclothing，anddonotsoreadilybecomeanobjectofforeigncommerce。Whentheyaresuperabundantinthecountrywhichproducesthem，itfrequentlyhappens，eveninthepresentcommercialstateoftheworld，thattheyareofnovaluetothelandlord。AgoodstonequarryintheneighbourhoodofLondonwouldaffordaconsiderablerent。InmanypartsofScotlandandWalesitaffordsnone。Barrentimberforbuildingisofgreatvalueinapopulousandwell—cultivatedcountry，andthelandwhichproducesitaffordsaconsiderablerent。ButinmanypartsofNorthAmericathelandlordwouldbemuchobligedtoanybodywhowouldcarryawaythegreaterpartofhislargetrees。
InsomepartsofthehighlandsofScotlandthebarkistheonlypartofthewoodwhich，forwantofroadsandwater—carriage，canbesenttomarket。Thetimberislefttorotupontheground。
Whenthematerialsoflodgingaresosuperabundant，thepartmadeuseofisworthonlythelabourandexpenseoffittingitforthatuse。Itaffordsnorenttothelandlord，whogenerallygrantstheuseofittowhoevertakesthetroubleofaskingit。
Thedemandofwealthiernations，however，sometimesenableshimtogetarentforit。ThepavingofthestreetsofLondonhasenabledtheownersofsomebarrenrocksonthecoastofScotlandtodrawarentfromwhatneveraffordedanybefore。ThewoodsofNorwayandofthecoastsoftheBalticfindamarketinmanypartsofGreatBritainwhichtheycouldnotfindathome，andtherebyaffordsomerenttotheirproprietors。