YousawthosepicturesoftheruinsofArica，aboutwhichourtalkbegan；andfromthemyoucanguesswellenoughforyourselfwhatatownlookslikewhichhasbeenruinedbyanearthquake。OfthemiseryandthehorrorwhichfollowsucharuinIwillnottalktoyou，nordarkenyouryoungspiritwithsadthoughtswhichgrownpeoplemustface，andoughttoface。Butthestrangenessofsomeofthetrickswhichtheearthquakeshocksplayishardlytobeexplained，evenbyscientificmen。Sometimes，itwouldseem，theforcerunsround，makingthesolidgroundeddy，aswatereddiesinabrook。Foritwillmakestraightrowsoftreescrooked；itwilltwistwholewallsround——orratherthegroundonwhichthewallsstand——withoutthrowingthemdown；itwillshiftthestonesofapillaroneontheothersideways，asifagianthadbeentryingtospinitlikeateetotum，andsoscrewedithalfinpieces。Thereisastorytoldbyawiseman，whosawtheplacehimself，ofthewholefurnitureofonehousebeinghurledawaybyanearthquake，andburiedundertheruinsofanotherhouse；andofthingscarriedhundredsofyardsoff，sothattheneighbourswenttolawtosettlewhowasthetrueownerofthem。Sometimes，again，theshockseemstocomeneitherhorizontallyinwaves，norcircularlyineddies，butvertically，thatis，straightupfrombelow；andthenthings——andpeople，alas！sometimes——arethrownupofftheearthhighintotheair，justasthingsspringupoffthetableifyoustrikeitsmartlyenoughunderneath。Bythatsamelaw（forthereisalawforeverysortofmotion）itisthattheearthquakeshocksometimeshurlsgreatrocksoffacliffintothevalleybelow。Theshockrunsthroughthemountaintillitcomestothecliffattheendofit；andthenthefaceofthecliff，ifitbeatallloose，fliesoffintotheair。Youmayseetheverysamethinghappen，ifyouwillputmarblesorbilliard—ballsinarowtouchingeachother，andstriketheonenearestyousmartlyinthelineoftherow。Alltheballsstandstill，exceptthelastone，andthatfliesoff。Theshock，liketheearthquakeshock，hasrunthroughthemall；butonlytheendone，whichhadnothingbeyonditbutsoftair，hasbeenmoved；andwhenyougrowold，andlearnmathematics，youwillknowthelawofmotionaccordingtowhichthathappens，andlearntoapplywhatthebilliard—ballshavetaughtyou，toexplainthewondersofanearthquake。Forinthiscase，asinsomanymore，youmustwatchMadamHowatworkonlittleandcommonthings，tofindouthowsheworksingreatandrareones。ThatiswhySolomonsaysthat\"afool’seyesareintheendsoftheearth，\"becauseheisalwayslookingoutforstrangethingswhichhehasnotseen，andwhichhecouldnotunderstandifhesaw；insteadoflookingatthepettycommonplacematterswhichareabouthisfeetalldaylong，andgettingfromthemsoundknowledge，andtheartofgettingmoresoundknowledgestill。
Anotherterribledestructionwhichtheearthquakebrings，whenitisclosetotheseaside，isthewashofagreatseawave，suchassweptinlastyearupontheislandofSt。Thomas，intheWestIndies；suchassweptinuponthecoastofPeruthisyear。Theseamoans，andsinksback，leavingtheshoredry；andthencomesinfromtheoffingamightywallofwater，ashighas，orhigherthan，manyatallhouse；sweepsfarinland，washingawayquaysandhouses，andcarryinggreatshipsinwithit；andthensweepsbackagain，leavingtheshipshighanddry，asshipswereleftinPeruthisyear。
Now，howisthatwavemade？Letusthink。Perhapsinmanyways。
ButtwoofthemIwilltellyouassimplyasIcan，becausetheyseemthemostlikely，andprobablythemostcommon。
Suppose，astheearthquakeshockranon，makingtheearthundertheseaheaveandfallinlongearth—waves，thesea—bottomsankdown。Thenthewateronitwouldsinkdowntoo，andleavetheshoredry；tillthesea—bottomroseagain，andhurledthewaterupagainagainsttheland。Thisisonewayofexplainingit，anditmaybetrue。Forcertainitis，thatearthquakesdomovethebottomofthesea；andcertain，too，thattheymovethewateroftheseaalso，andwithtremendousforce。Forshipsatseaduringanearthquakefeelsuchablowfromit（thoughitdoesthemnoharm）thatthesailorsoftenrushupondeckfancyingthattheyhavestruckuponarock；andtheforcewhichcouldgiveaship，floatinginwater，suchablowasthat，wouldbestrongenoughtohurlthousandsoftonsofwaterupthebeach，andontotheland。