,transcrib] ,note ,text emphasis d5ot$ z ,italics4 ,,! ,int]national ,sci5tific ,s]ies ,,vol4 ,,xxxv4 ,frontispiece4 ,illu/ration ,sections ( ,igne\s ,rocks1 illu/rat+ ! passage f ! glassy to ! cry/all9e /ructure4 #a4 ,vitre\s ,rock4 #b4 ,semi-,vitre\s ,rock4 #c4 ,vitre\s ,rock ) ,sphrulites4 #d4 ,rock ) ,crypto-cry/all9e ,base4 #e4 ,rock ) ,micro-cry/all9e ,base4 #f4 ,rock ( ,granite ,/ructure built up entirely ( ,cry/als4 ,see pp4 #fc-fh4 ,,volcanoes ,,:at ,,!y ,,are & ,,:at ,,!y ,,tea* ,,by ,,john ,w4 ,,judd1 ,f4,r4,s4 ,,pr(essor ,,( ,,geology ,,9 ,,! ,,royal ,,s*ool ,,( ,,m9es ,,) #if ,,illu/rations ,,six? ,,edition ,,london ,,kegan ,,paul1 ,,tr5*1 ,,tr,,bn] ,,co4 ,ltd4 ,,pat]no/] ,,h\se1 ,,*>+ ,,cross ,,road #aijc 7,! rights ( translation & ( reproduction are res]v$47 ,,preface4 ,9 prep>+ ?is "w1 ,i h aim$ at c>ry+ out a design sugge/$ to me by ! late ,mr4 ,p\lett ,scrope1 ! accompli%m5t ( :i* has be5 un=tunately delay$1 long] ?an ,i c\ld h wi%$1 by _m press+ duties4 ,mr4 ,scrope's well-kn[n works1 ',volcanoes' & ',! ,geology & ,ext9ct ,volcanoes ( ,c5tral ,france'--:i* pass$ ?r\gh sev]al editions 9 ?is c\ntry1 & h be5 translat$ into ! pr9cipal ,european languages--embody ! results ( mu* c>eful obs]vation & acute reason+ ^u ! que/ions :i* ! au?or made ! /udy ( 8 life4 ,9 ! fir/ ( ^! works ! ph5om5a ( volcanic activity are describ$1 & its causes discuss$2 9 ! second x is %[n t mu* insight conc]n+ ^! problems may be obta9$ by a /udy ( ! ru9$ & d5ud$ relics ( ! volcanoes ( =m] geological p]iods4 ,! appe>ance ( ^! works1 9 ! ye>s #ahbe & #ahbg respectively1 did mu* to prep>e ! m9ds ( ! e>li] cultivators ( sci5ce = ! reception ( ^? doctr9es ( geological uni=mity & cont9uity1 :i* 7 %ortly aft]w>ds s ably advocat$ by ,lyell 9 8 ',pr9ciples ( ,geology4' ,s9ce ! date ( ! appe>ance ( ! la/ editions ( ,scrope's works1 inquiry & speculation conc]n+ ! nature & orig9 ( volcanoes h be5 alike active1 & _m ( ! problems :i* 7 discuss$ by him1 n[ pres5t !mselves "u aspects entirely new & diff]5t f ^? 9 :i* he 0 accu/om$ to reg>d !m4 ,no "o 0 ev] m ready to welcome orig9al views or to submit to hav+ long-*]i%$ pr9ciples expos$ to ! ordeal ( free criticism ?an 0 ,scrope2 & few m5 reta9$ to s advanc$ an age ! p[] ( subject+ novel !ories to ! te/ ( a rigor\s comp>ison ) asc]ta9$ facts4 ,b ?is em95t geologi/ 0 n cont5t ) ! devotion ( 8 own "t & en]gies to ! advancem5t ( 8 fav\rite sci5ce1 = z increas+ age & gr[+ infirmities r5d]$ travel & p]sonal rese>* impossible1 he f\nd a new s\rce ( pleasure 9 seek+ out ! y\ng] work]s 9 ^? fields ( inquiry :i* he _h s long & successfully cultivat$1 & 9 fur!r+ _! ef=ts by 8 judici\s advice & k9dly aid4 ,among ! *os5 disciples ( ?is di/+ui%$ man1 :o w ev] be reg>d$ z "o ( ! *ief pione]s ( geological ?\ght1 ,i _h ! good =tune to be numb]$1 & :5 he committ$ to me ! task ( prep>+ a popul> exposition ( ! pres5t condition ( our k on volcanoes1 ,i felt t ,i _h be5 greatly hon\r$4 ,9 ord] to keep ! "w )9 ! prescrib$ limits1 & to avoid unnecess>y repetitions1 ,i h conf9$ myself to ! exam9ation ( su* select$ examples ( volcanoes z c\ld be %[n to be really typical ( all ! v>i\s classes :i* exi/ ^u ! globe2 & ,i h endeav\r$ f ! /udy ( ^! to d$uce ^? g5]al laws :i* appe> to gov]n volcanic action4 ,b x has1 at ! same "t1 be5 my aim to approa* ! "q f a some:at new /&po9t1 & to give an acc\nt ( ^? inve/igations :i* h 9 rec5t times ?r[n s mu* fre% light ^u ! :ole problem4 ,9 ?is way ,i h be5 l$ to dwell at "s l5g? ^u subjects :i* might n at fir/ sight appe> to be g]mane to ! "q "u discussion2--su* z ! *>act]s ( lavas reveal$ to u by microscopic exam9ation2 ! nature & movem5ts ( ! liquids enclos$ 9 ! cry/als ( igne\s rocks2 ! relations ( m9]als occurr+ 9 "s volcanic products to ^? f\nd 9 meteorites2 ! nature & orig9 ( ! rem>kable iron-masses f\nd at ,ovifak 9 ,gre5l&2 & ! indications :i* h be5 discov]$ ( analogies betwe5 ! composition & dynamics ( our e>? & ^? ( o!r memb]s ( ! family ( worlds to :i* x belongs4 ,:ile n evad+ ! discussion ( !oretical que/ions1 ,i h endeav\r$ to keep su* discussions 9 /rict subord9ation to t pres5tation ( ! results atta9$ by obs]vation & exp]im5t1 :i* con/itutes ! pr9cipal object ( ! "w4 ,! woodcuts :i* illu/rate ! volume are 9 "s cases prep>$ f photographs1 & ,i am indebt$ to ,mr4 ,coop] = ! skill ) :i* he has c>ri$ out my wi%es conc]n+ _! reproduction4 ,o!rs among ! engrav+s are copies ( sket*es :i* ,i made 9 ,italy1 ,hung>y1 ,bohemia1 & o!r volcanic di/ricts4 ,! :ole ( ! wood-blocks employ$ by ,mr4 ,p\lett ,scrope 9 8 "w on ,volcanoes 7 plac$ at my disposal be=e 8 dea?1 & su* ( !m z 7 useful = my purpose ,i h freely employ$4 ,to ,capta9 ,s4 ,p4 ,oliv]1 ,r4,a41 ,i am oblig$ = a beautiful draw+ made 9 ! ,isl& ( ,b\rbon1 & to ,mr4 ,norman ,locky] & 8 publi%]s1 ,messrs4 ,macmillan ,co41 = ! use ( sev]al wood-blocks illu/rat+ sun-spots & sol> prom95ces4 ,j4 ,w4 ,j4 ,london3 ,may #ahha4 ,,cont5ts4 ,,*apt] ,i4 ,,page ,,introductory3 ,,nature ,,( ,,! ,,enquiry #a ,,*apt] ,,ii4 ,,! ,,nature ,,( ,,volcanic ,,action #g ,,*apt] ,,iii4 ,,! ,,products ,,( ,,volcanic ,,action #ci ,,*apt] ,,iv4 ,,! ,,di/ribution ,,( ,,! ,,mat]ials ,,eject$ ,,f ,,volcanic ,,v5ts #fg ,,*apt] ,v4 ,,! ,,int]nal ,,/ructure ,,( ,,volcanic ,,m\nta9s #aab ,,*apt] ,,vi4 ,,! ,,v>i\s ,,/ructures ,,built ,,up ,,ar\nd ,,volcanic ,,v5ts #afa ,,*apt] ,,vii4 ,,! ,,succession ,,( ,,op]ations ,,tak+ ,,place ,,at ,,volcanic ,,c5tres #ahf ,,*apt] ,,viii4 ,,! ,,di/ribution ,,( ,,volcanoes ,,^u ,,! ,,surface ,,( ,,! ,,globe #bbd ,,*apt] ,,ix4 ,,volcanic ,,action ,,at ,,diff]5t ,,p]iods ,,( ,,! ,,e>?',s ,,hi/ory #bdg ,,*apt] ,x4 ,,! ,,"p ,,play$ ,,by ,,volcanoes ,,9 ,,! ,,economy ,,( ,,nature #bha ,,*apt] ,,xi4 ,,:at ,,volcanoes ,,tea* ,,u ,,conc]n+ ,,! ,,nature ,,( ,,! ,,e>?',s ,,int]ior #cjg ,,*apt] ,,xii4 ,,! ,,attempts ,,:i* ,,h ,,be5 ,,made ,,to ,,expla9 ,,! ,,causes ,,( ,,volcanic ,,action #cca ,,index #cga ,,illu/rations4 ,sections ( igne\s rocks illu/rat+ ! passage f ! glassy to ! cry/all9e /ructure ,frontispiece ,fig4 ,page #a4 ,/romboli1 view$ f ! nor?-we/1 ,april #ahgd to face p4 #aj #b4 ,map ( ! ,isl& ( ,/romboli #aa #c4 ,section ?r\gh ! ,isl& ( ,/romboli f nor?-we/ to s\?-ea/ #ac #d4 ,! crat] ( ,/romboli z view$ f ! side ( ! ,sci>ra dur+ an eruption on ! morn+ ( ,april #bd1 #ahgd4 #ad #e4 ,vesuvius 9 eruption1 z se5 f ,naples1 ,april #bf1 #ahgb4 7,f a photograph7 to face p4 #bd #f4 ,view ( ,vulcano1 ) ,vulcanello 9 ! =egr\nd--tak5 f ! s\? end ( ! ,isl& ( ,lip>i #dc #g4 ,m9ute cavities1 conta9+ liquids1 9 ! cry/als ( rocks4 7,aft] ,zirkel7 to face p4 #fj #h4 ,m9ute liquid-cavity 9 a cry/al1 ) a mov+ bubble4 7,aft] ,h>tley7 #fc #i4 ,cavity 9 cry/al1 conta9+ c>bonic-acid gas at a temp]ature ( #hf ,f41 & pass+ f ! liquid to ! gase\s condition4 7,aft] ,h>tley7 #fd #aj4 ,monte ,nuovo 7#ddj ft high7 on ! %ores ( ! ,bay ( ,naples4 7,aft] ,scrope7 #gf #aa4 ,map ( ! di/rict ar\nd ,naples1 %[+ ,monte ,nuovo & ! surr\nd+ volcanoes ( old] date #gh #ab4 ,outl9es ( ! summit ( ,vesuvius dur+ ! eruption ( #agfg4 7,aft] ,sir ,w4 ,hamilton7 to face p4 #hj #ac4 ,crat] ( ,vesuvius =m$ dur+ ! eruption ( #ahbb 7,aft] ,scrope7 #hb #ad4 ,crat] ( ,vesuvius 9 #agef1 f a draw+ made on ! spot4 7,aft] ,sir ,w4 ,hamilton7 #hd #ae4 ,! summit ( ,vesuvius 9 #agfg1 f an orig9al draw+4 7,aft] ,sir ,w1 ,hamilton7 #he #af4 ,summit ( ,vesuvius 9 #ahdc #hf #ag4 ,outl9es ( ,vesuvius1 %[+ its =m at diff]5t p]iods ( its hi/ory #hg #ah4 ,cascade ( lava tumbl+ ov] a cliff 9 ! ,isl& ( ,b\rbon4 7,aft] ,capt4 ,s4 ,p4 ,oliv]1 ,r4,a47 #ic #ai4 ,lava-/ream 7obsidian7 9 ! ,isl& ( ,vulcano1 %[+ ! imp]fect liquidity ( ! mass #ie #bj4 ,int]ior ( a rhyolitic lava-/ream 9 ! ,isl& ( ,lip>i1 %[+ broad1 sigmoidal folds1 produc$ by ! sl[ movem5ts ( ! mass #if #ba4 ,int]ior ( a rhyolitic lava-/ream 9 ! ,isl& ( ,lip>i1 %[+ ! complicat$ crumpl+s & puck]+s1 produc$ by ! sl[ movem5ts ( ! mass #if #bb4 ,vesuvian lava-/ream ( #aheh1 exhibit+ ! peculi> 'ropy' surfaces ( sl[ly-mov+ curr5ts4 7,f a photograph7 to face p4 #ih #bc4 ,vesuvian lava-/ream ( #ahgb1 exhibit+ ! r\gh c9d]y surfaces *>act]i/ic ( rapidly fl[+ curr5ts4 7,f a photograph7 to face p4 #if #bd4 ,conc5tric folds on mass ( cool$ lava4 7,aft] ,heaphy7 #ajj #be4 ,mass ( cool$ lava =m$ ov] a spiracle on ! slopes ( ,hawaii4 7,aft] ,dana7 #ajj #bf4 ,gr\p ( small cones ?r[n up on ! ,vesuvian lava-curr5t ( #ahee4 7,aft] ,s*midt7 #aja #bg4 ,natural section ( a lava-/ream 9 ! ,isl& ( ,vulcano1 %[+ ! compact c5tral portion & ! scoriace\s upp] & "u surfaces #ajd #bh4 ,section ( a lava-/ream expos$ on ! side ( ! riv] ,ard*e1 9 ! s\?-we/ ( ,france4 7,aft] ,scrope7 #ajf #bi4 ,portion ( a basaltic column f ! ,giant's ,causeway1 exhibit+ bo? ! ball-&-socket & ! t5on-&-mortise /ructure #ajg #cj4 ,ve9 ( gre5 pit*/one at ,*iaja di ,luna1 9 ! ,isl& ( ,ponza1 break+ up into regul> columns & into sph]ical masses ) a conc5tric s]ies ( jo9ts4 7,aft] ,scrope7 #ajh #ca4 ,illu/ration ( ! 'p]litic /ructure' 9 glassy rocks #aji #cb4 ,transv]se section ( a lava-/ream #aaa #cc4 ,! ,kamm]bhl1 or ,kamm]b]g1 ,bohemia 7z se5 f ! s\?-we/7 #aac #cd4 ,section ( ! ,kamm]bhl 9 ,bohemia #aad #ce4 ,natural section ( a volcanic cone 9 ! ,isl& ( ,vulcano #aaf #cf4 ,section 9 ! side ( ! ,kamm]bhl1 ,bohemia #aah #cg4 ,exp]im5tal illu/ration ( ! mode ( =mation ( volcanic cones1 compos$ ( fragm5tal mat]ials #abj #ch4 ,natural section ( a tuff-cone1 =m+ ! ,cape ( ,mis5um1 & exhibit+ ! peculi> int]nal arrangem5t1 *>act]i/ic ( volcanoes compos$ ( fragm5t>y mat]ials4 7,aft] ,scrope7 #aba #ci4 ,section ( a small scoria-cone =m$ )9 ! crat] ( ,vesuvius 9 ! ye> #ahce1 illu/rat+ ! fill+ up ( ! c5tral v5t ( ! cone by subsequ5t ejections4 7,aft] ,abi*7 #abb #dj4 ,volcanic cones compos$ ( scori1 & brea*$ on "o side by ! outfl[ ( lava-curr5ts4 7,aft] ,scrope7 #abh #da4 ,campo ,bianco1 9 ! ,isl& ( ,lip>i4 ,a pumice-cone brea*$ by ! outfl[ ( an obsidian lava-/ream to face p4 #abd #db4 ,volcanic cones 9 ,auv]gne1 :i* h suff]$ to "s ext5t f atmosph]ic d5udation4 7,aft] ,scrope7 #abd #dc4 ,exp]im5tal illu/ration ( ! mode ( =mation ( volcanic cones compos$ ( viscid lavas4 7,aft] ,rey]7 #abf #dd4 ,! ,gr& ,puy ( ,s>c\i1 compos$ ( tra*yte1 ris+ betwe5 two brea*$ scoria-cones 7,auv]gne74 7,aft] ,scrope7 #abf #de4 ,volcanic cone 7,mamelon7 compos$ ( v viscid lava 7,isl& ( ,b\rbon74 7,aft] ,bory de ,/4 ,v9c5t7 #abg #df4 ,ano!r ,mamelon 9 ! ,isl& ( ,b\rbon1 ) a crat] at its summit4 7,aft] ,bory de ,/4 ,v9c5t7 #abg #dg4 ,cliff-section 9 ! ,isl& ( ,madeira1 %[+ h[ a composite volcano is built up ( lava-/reams1 b$s ( scori1 & dykes4 7,aft] ,lyell7 #abe #dh4 ,section se5 at ! cascade1 ,ba9s du ,mont ,dore4 7,aft] ,scrope7 #acj #di4 ,section 9 ! ,isl& ( ,v5toti5ne1 %[+ a great /ream ( &esitic lava ov]ly+ /ratifi$ tuffs4 7,aft] ,scrope7 #acj #ej4 ,cliff on ! s\? side ( ! ,isl& ( ,san ,/ephano #aca #ea4 ,! headl& ( ,monte della ,gu>dia1 9 ! ,isl& ( ,ponza #aca #eb4 ,we/]n side ( ! same headl&1 z se5 f ! nor? side ( ,luna ,bay #acb #ec4 ,sea-cliff at ,il ,capo1 ! nor?-ea/ po9t ( ,sal9a1 %[+ /ratifi$ agglom]ates trav]s$ by num]\s dykes1 ! :ole be+ uncon=mably ov]laid by /ratifi$1 aque\s deposits #acg #ed4 ,section obs]v$ 9 ! ,val del ,bove1 ,etna1 %[+ a basaltic dyke1 f ! upp] "p ( :i* a lava-curr5t has fl[$ #ach #ee4 ,basaltic dykes project+ f masses ( /ratifi$ scori 9 ! sides ( ! ,val del ,bove1 ,etna #acd #ef4 ,%eets ( igne\s rock 7basalt7 intrud$ betwe5 b$s ( s&/one1 clay1 & lime/one 7,isl& ( ,skye7 #acg #eg4 ,plan ( ! dissect$ volcano ( ,mull 9 ! ,inn] ,hebrides to face p4 #adb #eh4 ,section ( ! volcano ( ,mull along ! l9e ,a ,b #adb #ei4 ,summit ( ! volcano ( ,monte ,sant' ,angelo1 9 ,lip>i1 exhibit+ a crat] ) walls worn d[n by d5udation #aeh #fj4 ,outl9es ( lava-cones #afj #fa4 ,diagram illu/rat+ ! =mation ( p>asitic cones along l9es ( fissure =m$ on ! flanks ( a great volcanic m\nta9 #afb #fb4 ,outl9e ( ,etna1 z se5 f ,catania #afb #fc4 ,outl9e ( ,etna1 z se5 f ! ,val del ,bronte #afc #fd4 ,plan ( ! volcano =m+ ! ,isl& ( ,is*ia #afc #fe4 ,a prim>y p>asitic cone1 ) a second>y "o at its base--,is*ia #afd #ff4 ,scoria-cone ne> ,auckl&1 ,new ,zeal&1 ) a lava-curr5t fl[+ f x4 7,aft] ,heaphy7 #afe #fg4 ,section ( rocks bel[ ! anci5t triassic volcano ( ,pr$azzo 9 ! ,tyrol #afe #fh4 ,cotopaxi1 z se5 f a di/ance ( n9ety miles4 7,aft] ,humboldt7 #afh #fi4 ,citlaltepetl1 or ! ,pic d',orizaba1 9 ,mexico1 z se5 f ! ,=e/ ( ,xalapa4 7,aft] ,humboldt7 #afi #gj4 ,lac ,pav51 9 ! ,auv]gne4 7,aft] ,scrope7 #aga #ga4 ,! crat]-lake call$ ,lago del ,bagno1 9 ,is*ia1 conv]t$ into a h>b\r #agb #gb4 ,lake ( ,gu/avila1 9 ,mexico4 7,aft] ,humboldt7 #agb #gc4 ,peak ( ,t5]iffe1 surr\nd$ by great crat]-r+s4 7,aft] ,piazzi-,smy?7 #age #gd4 ,! volcano ( ,b\rbon1 ris+ 9 ! mid/ ( a crat]-r+ f\r miles 9 diamet]4 7,aft] ,bory de ,/4 ,v9c5t7 #agf #ge4 ,! volcano ( ,b\rbon1 z se5 f ano!r po9t ( view1 ) ?ree conc5tric crat]-r+s encircl+ its base4 7,aft] ,bory de ,/4 ,v9c5t7 #agf #gf4 ,vesuvius z se5 f ,sorr5to1 half encircl$ by ! crat]-r+ ( ,somma #agg #gg4 ,outl9es ( v>i\s volcanoes illu/rat+ ! diff]5t relations ( ! crat]s to cones to face p4 #agh #gh4 ,isl& ?r[n up ,9 ! ,m$it]ranean ,sea 9 ,july & ,augu/1 #ahca4 7,aft] ! ,pr9ce de ,jo9ville7 #agi #gi4 ,s9t]-cones surr\nd+ ! orifices ( geys]s #ahc #hj4 ,diagram illu/rat+ ! mode ( =mation ( trav]t9e- & s9t]-t]races on ! sides ( a hill ( tuff #ahe #ha4 ,map ( ! volcanic gr\p ( ! ,lip>i ,isl&s1 illu/rat+ ! position ( ! l9es ( fissure ^u :i* ! volcanoes h be5 built up #aib #hb4 ,! ,puy de ,p>i\1 9 ! ,auv]gne1 illu/rat+ ! %ift+ ( eruption along a l9e ( fissures #aic #hc4 ,ideal section ( ! ,puy de ,p>i\ #aid #hd4 ,fissure =m$ on ! flanks ( ,etna dur+ ! emotion ( #ahfe4 7,aft] ,silve/ri7 #aid #he4 ,plan ( ! ,isl& ( ,vulcano1 bas$ on ! map ( ! ,italian ,gov]nm5t #aif #hf4 ,vulcanello1 ) its ?ree crat]s #aig #hg4 ,section ( basalt f ,ovifak1 ,gre5l&1 ) p>ticles ( metallic iron diffus$ ?r\gh its mass #cai #hh4 ,diagram illu/rat+ ! relations betwe5 ! t]re/rial & ! extra-t]re/rial rocks to face p4 #cbb #hi4 ,a gr\p ( sun-spots4 7,aft] ,sec*i7 #cfb #ij4 ,a sun-spot1 %[+ ! great masses ( inc&esc5t vap\r ris+ or fall+ )9 x4 7,aft] ,sec*i7 #cfc #ia4 ,! edge ( a sun-spot1 %[+ a portion ( ! prom95t masses ( inc&esc5t gas 7,a7 :i* deta*$ itself at ,b & float$ into ! mid/ ( ! cavity4 7,aft] ,norman ,locky]7 #cfc #ib4 ,draw+ ( a sol> prom95ce made by ,mr4 ,norman ,locky]1 ,m>* #ad1 #ahfi1 at #aa h4 #e m4 ,a4,m4 #cfd #ic4 ,! same object1 z se5 at #aa h4 #ae m4 on ! same day4 7,aft] ,norman ,locky]7 #cfe #id4 ,draw+s ( a sol> prom95ce at f\r diff]5t p]iods on ,septemb] #g1 #ahga4 7,aft] ,"y7 #cff #ie4 ,a gr\p ( ,lun> crat]s 7,maurolycus1 ,b>ocius1 c471 ! l>ge/ be+ m ?an sixty miles 9 diamet] #cfh ,,volcanoes4 ,,*apt] ,i4 ,,introductory3 ,,nature ,,( ,,! ,,inquiry4 ',:at is a volcano8' ,?is is a famili> "q1 (t5 address$ to u 9 our y\?1 :i* ',cate*isms ( ,univ]sal ,k1' & simil> s*ool manuals1 h taught u to reply to 9 "s su* t]ms z ! foll[+3 ',a volcano is a burn+ m\nta91 f ! summit ( :i* issue smoke & flames4' ,su* a /atem5t z ?is1 x is probable1 does n unfairly repres5t ! ideas :i* are1 ev5 at ! pres5t day1 popul>ly ent]ta9$ ^u ! subject4 ,b 9 ?is1 z 9 s _m o!r cases1 our fir/ /ep t[>ds ! acquirem5t ( sci5tific or exact k1 mu/ be ! unle>n+ ( :at we h be=e be5 l$ to reg>d z true4 ,! description :i* we h quot$ is n m]ely incomplete & inadequate z a :ole1 b ea* individual proposition ( :i* x is made up is grossly inaccurate1 &1 :at is worse1 p]v]sely mislead+4 ,9 ! fir/ place1 ! action :i* takes place at volcanoes is n 'burn+1' or combu/ion1 & be>s1 inde$1 no relation :atev] to t well-kn[n process4 ,nor are volcanoes necess>ily 'm\nta9s' at all2 ess5tially1 !y are j ! rev]se--namely1 holes 9 ! e>?'s cru/1 or out] portion1 by means ( :i* a communication is kept up betwe5 ! surface & ! int]ior ( our globe4 ,:5 m\nta9s d exi/ at c5tres ( volcanic activity1 !y are simply ! heaps ( mat]ials ?r[n out ( ^! holes1 & mu/ !re=e be reg>d$ n z ! causes b z ! consequ5ces ( ! volcanic action4 ,nei!r does ?is action always take place at ! 'summits' ( volcanic m\nta9s1 :5 su* exi/1 = eruptions occur q z frequ5tly on _! sides or at _! base4 ,t1 too1 :i* popul> fancy reg>ds z 'smoke' is really cond5s+ /eam or wat]y vap\r1 & ! suppos$ rag+ 'flames' are no?+ m ?an ! gl[+ light ( a mass ( molt5 mat]ial reflect$ f ^! vap\r cl\ds4 ,x is n difficult to und]/& h[ ^! false notions on ! subject ( volcanic action h come to be s g5]ally preval5t4 ,9 ! e>li] /ages ( its developm5t1 ! human m9d is mu* m cong5ially employ$ 9 dr9k+ 9 t :i* is m>vell\s ?an 9 se>*+ = t :i* is true4 ,x mu/ be admitt$1 too1 t ! gr& & /rik+ ph5om5a display$ by volcanoes are especially calculat$ to inspire t]ror & to excite sup]/ition1 & su* feel+s mo/ op]ate 9 prev5t+ ^? close & accurate obs]vations :i* alone c =m ! basis ( sci5tific reason+4 ,sid5ote3 ,,ideas ,,( ,,! ,,anci5ts4 ,! anci5ts 7 acqua9t$ only ) ! f\r or five active volcanoes 9 ! ,m$it]ranean area2 ! t]m 'volcano' be+ ! "n ( "o ( ^! 7,vulcano1 or ,volcano1 9 ! ,lip>i ,isl&s71 :i* has come to be appli$ to all simil> ph5om5a4 ,x is only 9 comp>atively mod]n times t x has become a kn[n act t _m hundr$s ( volcanoes exi/ ^u ! globe1 & are scatt]$ ov] almo/ e "p ( its surface4 ,classical my?ology appropriat$ ,vulcano z ! =ge ( ,heph/us1 & 8 ,roman repres5tative ,vulcan1 :ile ,etna 0 reg>d$ z =m$ by ! m\nta9s "u :i* a v5geful deity _h buri$ ! rebelli\s ,typhon2 x may be imag9$1 !re=e1 t any endeav\r to m closely inve/igate ! ph5om5a display$ at ^! localities w\ld be reg>d$1 n simply z an act ( tem]ity1 b z "o ( actual impiety4 ,9 m$ival times simil> feel+s w\ld op]ate ) n less =ce 9 ! same direction1 = ! popul> belief id5tifi$ ! subt]ranean fires ) a place ( ev]la/+ torm5t2 ,vulcano 0 reg>d$ z ! place ( puni%m5t ( ! ,arian ,emp]or ,!odosius1 :ile ,etna 0 assign$ to poor ,anne ,boleyn1 ! p]v]t] ( fai? 9 ! p]son ( its /\te/ def5d]4 ,t su* feel+s ( sup]/iti\s t]ror 9 connection ) volcanoes are1 ev5 at ! pres5t day1 f> f be+ ext9ct1 w be atte/$ by e travell] :o1 9 c>ry+ on inve/igations ab\t volcanic c5tres1 has _h to avail himself ( ! assi/ance ( guides & att5dants f among ! common p4 ,among ! great writ]s ( antiquity we f9d sev]al :o _h s f> emancipat$ _! m9ds f ! popul> sup]/itions z to be able to enunciate j & rational views ^u ! subject ( volcanoes4 ,until q rec5t times1 h[ev]1 _! tea*+ 0 q =gott5 or neglect$1 & ! mod]n sci5ce ( ,vulcanology may be said to h entirely gr[n up )9 ! la/ "o hundr$ ye>s4 ,! great pione] 9 ?is important bran* ( rese>* 0 ! illu/ri\s ,italian naturali/ ,spallanzani1 :o1 9 ! ye> #aghh1 visit$ ! sev]al volcanoes ( 8 native l&1 & publi%$ an acc\nt ( ! num]\s valuable & orig9al obs]vations :i* he _h made ^u !m4 ,ab\t ! same "t ! ,fr5* geologi/ ,dolomieu %[$ h[ mu* light might be ?r[n on ! nature ( volcanic action by a /udy ( ! v>i\s mat]ials :i* are eject$ f volcanic v5ts2 :ile our own c\ntryman4 ,sir ,william ,hamilton1 0 engag$ 9 a sy/ematic /udy ( ! *anges 9 =m ( volcanic m\nta9s1 & ( ! causes :i* det]m9e _! gr[?4 ,at a some:at lat] date ! ?ree ,g]man naturali/s4 ,von ,bu*1 ,humboldt1 & ,abi*1 greatly ext5d$ our k ( volcanoes by _! travels 9 diff]5t portions ( ! globe4 ,sid5ote3 ,,"* ,,( ,,mod]n ,,rese>*es4 ,! fir/ attempt1 h[ev]1 to frame a satisfactory !ory ( volcanic action1 & to %[ ! "p :i* volcanoes h play$ 9 ! pa/ hi/ory ( our globe1 toge!r ) _! place 9 its pres5t economy1 0 made 9 #ahbe1 by ,p\lett ,scrope1 ^: great "w1 ',consid]ations on ,volcanoes1' may be reg>d$ z ! e>lie/ sy/ematic treatise on ,vulcanology4 ,s9ce ! publication ( ?is "w1 _m new l9es ( inquiry h be5 op5$ up 9 connection ) ! subject1 & fre% me?ods ( rese>* h be5 devis$ & appli$ to x4 ,m exact obs]vations ( travell]s ov] wid] areas h greatly multipli$ ! facts ^u :i* we may reason & speculate1 & _m errone\s hypo!ses :i* _h gr[n up 9 connection ) ! subject h be5 remov$ by pati5t & critical inquiry4 ,we propose 9 ! foll[+ pages to give an outl9e ( ! pres5t /ate ( k ^u ! subject1 & to indicate ! be>+s ( ^? conclusions :i* h already be5 arriv$ at1 ^u ! great que/ions ( ! hi/ory ( our globe & ! relations :i* x be>s to ! o!r portions ( ! univ]se4 ,9 attempt+ ?is task we _c d bett] ?an take up ! sev]al l9es ( inquiry 9 ! ord] 9 :i* !y h be5 seiz$ ^u & work$ out by ! orig9al inve/igators2 = nev]1 p]haps1 is ! developm5t ( ?\ght 9 ! individual m9d s natural 9 its me?ods1 & s p]man5t 9 its effects1 z :5 x obeys ^? laws :i* det]m9$ its gr[? 9 ! collective m9d ( ! race4 ,9 our m9ds1 z 9 our bodies1 developm5t 9 ! individual is an epitome1 or microcosmic reproduction1 ( evolution 9 ! species4 ,,*apt] ,,ii4 ,,! ,,nature ,,( ,,volcanic ,,action4 ,! dose inve/igation ( :at goes on )9 a volcanic v5t may appe> at fir/ sight to be a task beset ) s _m difficulties & dang]s t we may be tempt$ to ab&on x z altoge!r hopeless4 ,at ! fir/ record$ eruption ( ,vesuvius ! eld] ,pl9y lo/ 8 life 9 an attempt to approa* ! m\nta9 & exam9e ! action :i* 0 tak+ place !re2 & dur+ ! la/ great outbur/ ( ! same volcano a b& ( ,neapolitan /ud5ts1 ^: curiosity 0 great] ?an _! prud5ce1 %>$ ! same fate4 ,b 9 bo? ^! cases ! inquir]s paid ! p5alty ( hav+ adopt$ a wrong me?od4 ,if we wi% to exam9e ! mode ( work+ ( a complicat$ /eam-eng9e1 x w be ( little avail = u to wat* ! ma*9]y :5 ! full bla/ ( /eam is turn$ on1 & ! rapid movem5ts ( lev]s1 p9ions1 & slides baffle all attempts to foll[ !m1 & r5d] hopeless e ef=t to trace _! connection ) "o ano!r4 ,b if "s fri5dly h& turn (f ! great] "p ( ! /eam-supply1 !n1 z ! rods move sl[ly backw>ds & =w>ds1 z ! :eels make _! measur$ revolutions1 & ! valves axe se5 gradually op5+ & %utt+1 we may h an opportunity ( det]m9+ ! relations ( ! sev]al p>ts ( ! ma*9e to "o ano!r1 & ( arriv+ at j conclusions conc]n+ ! plan on :i* x is con/ruct$4 ,nor c we d\bt t ! p>ts ( ! ma*9e be> ! same relation to "o ano!r1 & t _! movem5ts take place 9 precisely ! same ord]1 :5 ! supply ( /eam is l>ge z :5 x is small4 ,n[1 z we %all %[ 9 ! sequel1 a volcano is a k9d ( great natural /eam-eng9e1 & our be/ me?od ( inve/igat+ its action is to wat* x :5 a "p ( ! /eam-supply is cut (f4 ,x is true t we _c at w control ! s\rce ( supply ( /eam to a volcano1 z we c 9 a /eam-eng9e1 b z "s volcanoes h usually only a small /eam-supply1 & ne>ly all volcanoes v>y greatly 9 ! int5sity ( _! action at diff]5t p]iods1 we c1 by a c>eful selection ( ! object or ! "t ( our /udy1 ga9 all ^? advantages :i* w\ld be obta9$ by regulat+ its action = ourselves4 ,spallanzani appe>s to h be5 ! fir/ to p]ceive ! important fact1 t ! nature ( volcanic action rema9s ! same1 h[ev] its int5sity may v>y4 ,tak+ advantage ( ! circum/ance t !re exi/s 9 ! ,m$it]ranean ,sea a volcano--,/romboli--:i* = at lea/ #b1jjj ye>s has be5 9 a con/ant & regul>1 b n 9 a viol5t or dang]\s1 /ate ( activity1 he visit$ ! spot1 & made ! s]ies ( c>eful obs]vations :i* laid ! f\ndation ( our k ( ! 'physiology ( volcanoes4' ,s9ce ! "t ( ,spallanzani1 _m o!r inve/igators h visit$ ! crat] ( ,/romboli1 & !y h be5 able to confirm & ext5d ! obs]vations ( ! great ,italian naturali/1 z to ! "* ( ! action :i* is con/antly tak+ place )9 x4 ,we _c bett] illu/rate ! nature ( volcanic action ?an by describ+ :at has be5 witness$ by num]\s obs]v]s )9 ! crat] ( ,/romboli1 :]e x is possible to wat* ! s]ies ( op]ations go+ on by ! h\r toge!r1 & to d s )\t hav+ our judgm5t w>p$ ei!r by an excit$ imag9ation or ! s5se ( dang]4 ,sid5ote3 ,,appe>ance ,,( ,,/romboli ,,f ,a ,,di/ance4 ,9 ! sket*1 fig4 #a1 :i* 0 made on ,april #bj1 #ahgd1 ,i h %[n ! appe>ance :i* ?is int]e/+ volcano usually pres5ts1 :5 view$ f a di/ance4 ,! isl& is ( rudely circul> outl9e1 & conical =m1 & rises to ! height ( #c1jij feet above ! level ( ! ,m$it]ranean4 ,f a po9t on ! side ( ! m\nta91 masses ( vap\r are se5 to issue1 & ^! unite to =m a cl\d ov] ! m\nta91 ! outl9e ( ?is vap\r-cl\d v>y+ cont9ually accord+ to ! hygrometric /ate ( ! atmosph]e1 & ! direction & =ce ( ! w9d4 ,at ! "t :5 ?is sket* 0 made1 ! vap\r-cl\d 0 spread 9 a great horizontal /ratum ov]%ad[+ ! :ole isl&1 b x 0 cle>ly se5 to be made up ( a numb] ( globul> masses1 ea* ( :i*1 z we %all h]eaft] see1 is ! product ( a di/9ct outbur/ ( ! volcanic =ces4 ,view$ at night-"t1 ,/romboli pres5ts a f> m /rik+ & s+ul> spectacle4 ,! m\nta91 ) its vap\r canopy1 is visible ov] an area hav+ a radius ( m ?an #ajj miles4 ,:5 wat*$ f ! deck ( a vessel any:]e )9 ?is area1 a gl[ ( r$ light is se5 to make its appe>ance f "t to "t above ! summit ( ! m\nta92 ?is gl[ ( light may be obs]v$ to increase gradually 9 int5sity1 & !n z gradually to die away4 ,aft] a %ort int]val ! same appe>ances are repeat$1 & ?is goes on till ! increas+ light ( ! dawn causes ! ph5om5on to be no long] visible4 ,! resemblance pres5t$ by ,/romboli to a 'fla%+ light' on a mo/ gigantic scale is v /rik+1 & ! m\nta9 has long be5 kn[n z '! ligh?\se ( ! ,m$it]ranean4' ,x mu/ be po9t$ out1 h[ev]1 t 9 two v important p>ticul>s ! appe>ances pres5t$ by ,/romboli diff] m>k$ly f ^? rhy?mical gleams exhibit$ by ! 'fla%+-lights' ( our coa/s4 ,9 ! fir/ place1 ! int]vals betwe5 successive fla%es are v unequal1 v>y+ f less ?an "o m9ute to tw5ty m9utes1 or ev5 m2 & 9 ! second place1 ! duration & int5sity ( ! r$ gl[ above ! m\nta9 are subject to l v>iation1 be+ sometimes a mom5t>y sc>cely visible gleam1 & at o!rs a vivid bur/ ( light :i* illum9ates ! sky to a consid]able di/ance r\nd4 ,illu/ration3 ,fig4 #a4--,/romboli1 view$ f ! ,nor?-we/1 ,april #ahgd4 ,illu/ration3 ,fig4 #b4--,map ( tub ,isl& ( ,/romboli4 7,scale ab\t two in*es to a mile47 ,sid5ote3 ,,g5]al ,,features ,,( ,,! ,,m\nta94 ,let u n[ draw ne> & exam9e ?is wond]ful ph5om5on ( a m\nta9 :i* seem+ly ev] burns ) fire1 & yet is n consum$4 ,! g5]al =m ( ! ,isl& ( ,/romboli w be ga!r$ f an inspection ( ! plan1 fig4 #b1 :i* is copi$ f a map publi%$ by ! ,italian ,gov]nm5t4 ,:5 we l& ^u ! isl&1 we f9d t x is entirely built up ( su* mat]ials z we "k to be eject$ f volcanoes2 inde$1 x resembles on a gigantic scale ! surr\nd+s ( an iron furnace1 ) its heaps ( c9d]s & masses ( slag4 ,! irregul>ity 9 ! =m ( ! isl& is at once se5 to be due to ! action ( ! w9d1 ! ra91 & ! waves ( ! surr\nd+ sea1 :i* h remov$ ! loose1 c9d]y mat]ials at "s po9ts1 & left ! h>d1 slaggy masses /&+ up prom95tly at o!rs4 ,?is great heap ( c9d]y & slaggy mat]ials rises1 z we h said1 to a height ( m ?an #c1jjj feet above ! sea-level1 b ev5 ?is measurem5t does n give a j idea ( its va/ bulk4 ,s\nd+s 9 ! sea surr\nd+ ! isl& %[ t ! bottom gradually %elves ar\nd ! %ores to ! dep? ( ne>ly #fjj fa?oms1 s t ,/romboli is a great conical mass ( c9d]s & slaggy mat]ials1 hav+ a height ( ov] #f1jjj feet1 & a base ^: diamet] exce$s f\r miles4 ,! g5]al =m & proportions ( ?is mass w be bett] und]/ood by an exam9ation ( ! section1 fig4 #c1 :i* is also con/ruct$ f ! mat]ials furni%$ by ! map ( ! isl& issu$ by ! ,italian ,gov]nm5t4 ,! same section1 & ! map1 fig4 #b1 w s]ve to make cle> ! position & relations ( ! po9t on ! m\nta9 at :i* ! volcanic activity takes place4 ,at a spot on ! nor?-we/ slope ( ! m\nta91 ab\t #a1jjj feet bel[ its summit1 & #b1jjj feet above ! level ( ! sea1 !re exi/s a circul> depression1 ! pres5t active 'crat]' ( ! volcano2 & lead+ d[n f ?is to ! sea !re is a flat slope mak+ an angle ( ab\t #ce ) ! horizon1 & kn[n z ! ',sci>ra4' ,! ,sci>ra is b\nd$ by /eep cliffs1 z %[n 9 ! sket* fig4 #a1 & ! plan fig4 #b4 ,illu/ration3 ,fig4 #c4--,section ?r\gh ! ,isl& ( ,/romboli f n4w4 to s4e4 a4 ,highe/ summit ( ! m\nta91 c4 ,cratre del ,fossa1 b4 ,po9t ov]look+ ! crat]1 d4 ,/eep slope kn[n z ! ,sci>ra del ,fuoco4 e4 ,cont9uation ( ! same slope b5ea? ! level ( ! sea4 f4 ,/eep cliffs ( ! ,punta dell' ,omo4 ,sid5ote3 ,,=m ,,& ,,function ,,( ,,! ,,crat]4 ,if we climb up to ?is sc5e ( volcanic activity1 we %all be able to wat* n>r[ly ! op]ations :i* are go+ on !re4 ,on ! morn+ ( ! #bd? ( ,april1 #ahgd1 ,i paid a visit to ?is int]e/+ spot 9 ord] to get a ne> view ( :at 0 tak+ place4 ,on rea*+ a po9t ^u ! side ( ! ,sci>ra1 f :i* ! crat] 0 9 full view be=e me1 ,i witness$1 & made a sket* (1 an outbur/ :i* !n took place1 & ?is sket* has be5 reproduc$ 9 fig4 #d4 ,be=e ! outbur/1 num]\s light curl+ wrea?s ( vap\r 7 se5 asc5d+ f fissures on ! sides & bottom ( ! crat]4 ,sudd5ly1 & )\t ! slighte/ w>n+1 a s\nd 0 he>d l t produc$ :5 a locomotive bl[s (f its /eam at a railway-/ation2 a great volume ( wat]y vap\r 0 at ! same "t ?r[n viol5tly into ! atmosph]e1 & ) x !re 7 hurl$ upw>ds a numb] ( d>k fragm5ts1 :i* rose to ! height ( #djj or #ejj feet above ! crat]1 describ+ curves 9 _! c\rse1 & !n fall+ back ^u ! m\nta94 ,mo/ ( ^! fragm5ts tumbl$ into ! crat] ) a l\d1 rattl+ noise1 b "s ( !m fell outside ! crat]1 & a few roll$ d[n ! /eep slope ( ! ,sci>ra into ! sea4 ,"s ( ^! fall+ fragm5ts 7 f\nd to be /ill hot & gl[+1 & 9 a semi-molt5 condition1 s t !y readily receiv$ ! impression ( a co9 ?ru/ into !m4 ,illu/ration3 ,fig4 #d4--,! ,crates ( ,/romboli z view$ f ! side ( ! ,sci>ra dur+ an eruption on ! morn+ ( ,april #bd1 #ahgd4 ,sid5ote3 ,,ap]tures ,,at ,,! ,,bottom ,,( ,,! ,,crat]4 ,b on ! upp] side ( ! crat]1 at ! po9t m>k$ #f1 on ! section fig4 #c1 !re exi/s a spot f :i* we c look d[n ^u ! bottom ( ! crat]1 & view ! op]ations tak+ place !re4 ,?is is ! place :]e ,spallanzani & o!r lat] inve/igators h c>ri$ on _! obs]vations1 &1 :5 ! w9d is bl[+ f ! spectator t[>ds ! crat]1 he may sit = h\rs wat*+ ! wond]ful sc5e display$ be=e him4 ,! black slaggy bottom ( ! crat] is se5 to be trav]s$ by _m fissures or cracks1 f mo/ ( :i* curl+ jets ( vap\r issue quietly1 & gradually m+le ) & disappe> 9 ! atmosph]e4 ,b besides ^! small] cracks at ! bottom ( ! crat]1 sev]al l>g] op5+s are se51 :i* v>y 9 numb] & position at diff]5t p]iods2 sometimes only "o ( ^! ap]tures is visible1 at o!rs z _m z six or sev51 & ! ph5om5a pres5t$ at ^! l>g] ap]tures are especially wor?y ( c>eful inve/igation4 ,^! l>g] ap]tures1 if we /udy ! nature ( ! action tak+ place at !m1 may be divid$ into ?ree classes4 ,f ^? ( ! fir/ class1 /eam is emitt$ ) l\d1 snort+ puffs1 l ^? produc$ by a locomotive-eng9e1 b f> less regul> & rhy?mical 9 _! succession4 ,9 ! second class ( ap]tures masses ( molt5 mat]ial are se5 well+ out1 &1 if ! position ( ! ap]ture be fav\rable1 fl[+ outside ! crat]2 f ?is liquid molt5 mass /eam is se5 to escape1 sometimes 9 consid]able quantities4 ,! op5+s ( ! ?ird class pres5t /ill m int]e/+ appe>ances4 ,)9 ! walls ( ! ap]ture a viscid or semi-liquid sub/ance is se5 sl[ly heav+ up & d[n4 ,z we wat* ! see?+ mass ! agitation )9 x is obs]v$ to increase gradually1 & at la/ a gigantic bubble is =m$ :i* viol5tly bur/s1 :5 a great ru% ( /eam takes place1 c>ry+ fragm5ts ( ! scum-l surface ( ! liquid high into ! atmosph]e4 ,if we visit ! crat] by night1 ! appe>ances pres5t$ are f\nd to be /ill m /rik+ & sugge/ive4 ,! small] cracks & l>g] op5+s gl[ ) a ruddy light4 ,! liquid matt] is se5 to be r$- or ev5 :ite-hot1 :ile ! scum or cru/ :i* =ms ^u x is ( a dull r$ col\r4 ,e "t a bubble bur/s & ! cru/ is brok5 up by ! escape ( /eam1 a fre%1 gl[+ surface ( ! inc&esc5t mat]ial is expos$4 ,if at ^! mom5ts we look up at ! vap\r-cl\d cov]+ ! m\nta91 we %all at once und]/& ! cause ( ! s+ul> appe>ances pres5t$ by ,/romboli :5 view$ f a di/ance at night1 = ! great masses ( vap\r are se5 to be lit up ) a vivid1 ruddy gl[1 l t produc$ :5 an eng9e-driv] op5s ! door ( ! furnace & illum9ates ! /ream ( vap\r issu+ f ! funnel ( 8 locomotive4 ,let u n[ endeav\r to analyse ! ph5om5a s admirably display$ be=e u 9 ! crat] ( ,/romboli4 ,! ?ree ess5tial conditions on :i* ! production ( ^! ph5om5a seems to dep5d are ! foll[+3 fir/1 ! exi/5ce ( c]ta9 ap]tures or cracks communicat+ betwe5 ! int]ior & ! surface ( ! e>?2 secondly1 ! pres5ce ( matt] 9 a highly heat$ condition b5ea? ! surface2 & ?irdly1 ! exi/5ce ( great quantities ( wat] imprison$ 9 ! subt]ranean regions--:i* wat]1 escap+ z /eam1 gives rise to all ^? active ph5om5a we h be5 describ+4 ,sid5ote3 ,,cause ,,( ,,! ,,gl[+ ,,light4 ,we h said1 at ! outset1 t !re exi/s no analogy :atev] betwe5 ! action :i* takes place 9 volcanoes & ! op]ation ( burn+ or combu/ion4 ,occasionally1 x is true1 c]ta9 inflammable sub/ances are =m$ by ! action go+ on )9 ! volcano1 & ^! inflammable sub/ances1 tak+ fire1 produce real flames4 ,su* flames are1 h[ev]1 9 almo/ all cases only feebly lum9\s1 & d n give rise to any conspicu\s appe>ances4 ,:at is usually tak5 = flame dur+ volcanic eruptions is simply1 z we h already po9t$ out1 ! gl[+ r$-hot surface ( a mass ( molt5 rock1 reflect$ f a vap\r-cl\d hang+ ov] x4 ,! r$ gl[ obs]v$ ov] a volcano 9 eruption is inde$ precisely simil> 9 its nature & orig9 to t :i* is se5 above ,london dur+ a night ( heavy fog1 & :i* is produc$ by ! reflection ( ! gas-lights ( ! city f ! innum]able p>ticles ( wat]-vap\r diffus$ ?r\gh ! atmosph]e4 ,fires1 ( c\rse1 occur :5 ! molt5 & inc&esc5t mat]ials p\r$ out f a volcano come 9 contact ) inflammable sub/ances1 su* z =e/s & h\ses1 b 9 ^! cases ! combu/ion is q a second>y ph5om5on4 ,!re is ano!r popul> delusion conc]n+ volcanic action1 :i* x may be necess>y to ref] to & to combat4 ,f ! well-kn[n fact t sulphur or brim/one is f\nd abundantly 9 volcanic regions1 ! popul> belief has aris5 t ?is highly inflammable sub/ance has some?+ to d ) ! production ( ! eruptions ( volcanoes4 ,9 s*ool-books :i* 71 until comp>atively rec5t ye>s1 9 con/ant use 9 ?is c\ntry1 ! /atem5t may be f\nd t by bury+ c]ta9 quantities ( sulphur1 iron-pyrites1 & *>coal 9 a hole 9 ! gr\nd1 we may =m a m9iature volcano1 & produce all ! ess5tial ph5om5a ( a volcanic eruption4 ,no great] mi/ake c\ld possibly be made4 ,! *emical reactions :i* take place :5 sulphur & o!r sub/ances are made to act ^u ea* o!r diff] entirely f ! ph5om5a ( volcanic action4 ,! sulphur :i* is f\nd 9 volcanic regions is ! result & n ! cause ( volcanic action4 ,among ! mo/ common sub/ances emitt$ f volcanic v5ts along ) ! /eam are ! two gases1 sulphur\s acid & sulphurett$ hydrog54 ,:5 ^! two gases come into contact ) "o ano!r1 *emical action takes place1 & ! elem5ts conta9$ 9 !m--oxyg51 hydrog51 & sulphur--are free to gr\p !mselves toge!r 9 an entirely new fa%ion2 ! consequ5ce ( ?is is t wat] & sulphuric acid 7oil ( vitriol7 are =m$1 & a c]ta9 quantity ( sulphur is set free4 ,! wat] escapes into ! atmosph]e1 ! sulphuric acid comb9es ) lime1 iron1 or o!r sub/ances conta9$ 9 ! surr\nd+ rocks1 & ! sulphur builds up cry/als 9 any cavities :i* may happ5 to exi/ 9 ^! rocks4 ,sid5ote3 ,,volcanic ,,action ,,resembles ,,boil+4 ,if1 h[ev]1 c>eful & exact obs]vations1 l ^? c>ri$ on at ,/romboli1 compel u to reject ! popul> notions conc]n+ ! suppos$ resemblance betwe5 volcanic action & ! combu/ion ( sulphur or o!r sub/ances1 !y nev]!less sugge/ analogies ) c]ta9 o!r simple & well-kn[n op]ations4 ,& 9 pursu+ ^! analogies1 we are l$ to ! recognition ( "s admirable illu/rations bo? ( ! att5dant ph5om5a & ( ! true cause ( volcanic outbur/s4 ,no "o c look d[n on ! mass ( see?+ mat]ial 9 viol5t agitation )9 ! fissures at ! bottom ( ! crat] ( ,/romboli1 )\t be+ =cibly rem9d$ ( ! appe>ances pres5t$ by liquids 9 a /ate ( boil+ or ebullition4 ,! gl[+ mat]ial seems to be agitat$ by two k9ds ( movem5ts1 ! "o :irl+ or rotatory1 ! o!r v]tical or up-&-d[n 9 its direction4 ,! fluid mass 9 ?is way appe>s to be gradually impell$ upw>ds1 till x approa*es ! lips ( ! ap]ture1 :5 va/ bubbles are =m$ ^u its surface1 & to ! sudd5 bur/+ ( ^! ! ph5om5a ( ! eruption are due4 ,n[ if we take a tall n>r[ vessel & fill x ) porridge or "s simil> sub/ance ( imp]fect fluidity1 we %all be able1 by plac+ x ov] a fire1 to imitate v closely inde$ ! appe>ances pres5t$ 9 ! crat] ( ,/romboli4 ,z ! temp]ature ( ! mass rises1 /eam is g5]at$ )9 x1 & 9 ! ef=ts ( ?is /eam to escape1 ! sub/ance is set 9 viol5t movem5t4 ,^! movem5ts ( ! mass are p>tly rotatory & p>tly v]tical 9 _! direction2 z fre% /eam is g5]at$ 9 ! mass its surface is gradually rais$1 :ile an escape ( ! /eam is imm$iately foll[$ by a fall ( ! surface4 ,?us an up-&-d[n movem5t ( ! liquid is ma9ta9$1 b z ! g5]ation ( /eam goes on fa/] ?an x c escape ?r\gh ! viscid mass1 !re is a con/ant t5d5cy 9 ! latt] to rise t[>ds ! m\? ( ! vessel4 ,at la/1 z we "k1 if heat cont9ues to be appli$ to ! vessel1 ! fluid cont5ts w be =c$ up to its edge & a cata/rophe w occur2 ! /eam be+ sudd5ly & viol5tly lib]at$ f ! bubbles =m$ on ! surface ( ! mass1 & a consid]able quantity ( ! mat]ial =cibly expell$ f ! vessel4 ,! sudd5ness & viol5ce ( ?is cata/rophe is easily acc\nt$ =1 if we be> 9 m9d t ! escap+ /eam acts aft] ! mann] ( a compress$ spr+ :i* is sudd5ly releas$4 ,/eam is fir/ =m$ at ! bottom ( ! vessel :i* is 9 contact ) ! fire2 b "h x is "u ! pressure ( ! :ole mass ( ! liquid1 & moreov]1 ! viscidity ( ! sub/ance t5ds to ret>d ! union ( ! /eam bubbles & _! rise to ! surface ( ! mass4 ,b :5 ! pressure is reliev$ by ! bur/+ ( bubbles at ! surface1 ! :ole ( ! g5]at$ /eam t5ds to escape sudd5ly4 ,sid5ote3 ,,escape ,,( ,,/eam-,,bubbles ,,f ,,lava4 ,n[ )9 ! crat] ( ,/romboli we h precisely ! necess>y conditions = ! display ( ! same s]ies ( op]ations4 ,9 ! ap]tures at ! bottom !re exi/s a quantity ( imp]fectly fluid mat]ials at a high] temp]ature1 conta9+ wat] entangl$ 9 its mass4 ,z ?is wat] passes into ! /ate ( /eam x t5ds to escape1 & 9 s do+ puts ! :ole mass into viol5t movem5t4 ,:5 ! /eam rises to ! surface1 bubbles are =m$1 & ! =mation ( ^! bubbles is promot$ by ! circum/ance t ! liquid mass1 :]e expos$ to ! atmosph]e1 becomes *ill$1 & !reby r5d]$ less p]fectly fluid4 ,by ! bur/+ ( ^! bubbles ! pressure is p>tially reliev$1 & a viol5t escape ( ! p5t-up /eam takes place ?r\gh ! :ole mass4 ,equilibrium be+ ?us re/or$1 !re foll[s a long] or %ort] int]val ( quiesc5ce1 dur+ :i* /eam is be+ g5]at$ & collect$ )9 ! mass1 & ! s]ies ( op]ations :i* we h describ$ !n recomm5ces4 ,!re is "o o!r consid]ation :i* mu/ be borne 9 m9d 9 connection ) ?is subject4 ,x is well kn[n t if wat] be subject$ to suffici5tly great pressure x may be rais$ to a v high temp]ature & /ill reta9 its liquid condition4 ,:5 ?is pressure is remov$1 h[ev]1 ! :ole mass passes at once into ! condition ( /eam or wat]-gas2 & ! gas ?us =m$ at high temp]atures has a proportionably high t5sion4 ,9 a ,pap9's dige/] wat] conf9$ 9 a /rong vessel is rais$ to temp]atures f> above its ord9>y boil+-po9t1 & f any op5+ 9 su* a vessel ! /eam escapes ) prodigi\s viol5ce4 ,n[1 at consid]able dep?s b5ea? ! e>?'s surface1 & "u ! pressure ( _m hundr$s or ?\s&s ( feet ( solid rock1 wat] /ill reta9+ its liquid condition may become int5sely heat$4 ,:5 ! pressure is reliev$ by ! =mation ( a crack or fissure 9 ! sup]9cumb5t mass ( rock1 ! escape ( ! sup]heat$ /eam w be ( v viol5t "*1 & may be att5d$ ) ! mo/ /rik+ & de/ructive results4 ,9 ! exi/5ce ( high temp]atures b5ea? ! e>?'s surface1 & ! pres5ce 9 ! same regions ( imprison$ wat] capable ( pass+ into ! highly ela/ic gas :i* we call /eam1 we h a cause fully compet5t to produce all ! ph5om5a :i* we h describ$ z occurr+ at ,/romboli4 ,x may at fir/ sight appe> t ! gr& & t]rible displays ( viol5ce witness$ dur+ a great volcanic eruption diff] fundam5tally 9 _! "* & _! orig9 f ^? feeble outbur/s :i* we are able to exam9e closely & analyse rigor\sly at ,/romboli4 ,b t su* is n ! case a few simple consid]ations w soon conv9ce u4 ,sid5ote3 ,,/romboli ,,comp>$ ,,) ,,vesuvius4 ,al?\gh ,/romboli usually displays ! subdu$ & mod]ate activity :i* we h be5 describ+1 yet ! int5sity ( ! action go+ on )9 x is subject to consid]able v>iation4 ,occasionally ! viol5ce ( ! outbur/s is greatly increas$--! ro>+ ( ! /eam-jets may be he>d = _m miles ar\nd1 consid]able /reams ( inc&esc5t liquefi$ rock fl[ d[n ! ,sci>ra into ! sea1 & ! explosions 9 ! crat] are f> m frequ5t & en]getic1 c9d]s & fragm5ts ( rock be+ scatt]$ all ov] ! isl& & ! surr\nd+ seas4 ,on ! o!r h&1 volcanoes l ,vesuvius1 :i* are sometimes ! sc5e ( eruptions on ! v gr&e/ scale1 at o!rs subside into a tempor>y /ate ( mod]ate activity q simil> 9 "* to t :i* is ! normal condition ( ,/romboli4 ,?us1 %ortly be=e ! great eruption ( ,vesuvius 9 ,april #ahgb1 a small cone 0 =m$ ne> ! edge ( ! crat]1 & dur+ "s mon?s obs]v]s c\ld wat*1 9 ease & safety1 a s]ies ( small explosions tak+ place1 q simil> 9 _! "* & att5dant ph5om5a to ^? :i* we h describ$ z occurr+ at ,/romboli4 ,fr5* geologi/s are 9 ! habit ( def9+ ! condition ( activity 9 a volcano by speak+ ( ! m quiet &1 regul> /ate z ! ',/rombolian /age1' & ! m viol5t & p>oxysmal z ! ',vesuvian /age'2 b ! two conditions are1 z we h se51 pres5t$ by ! same volcano at diff]5t p]iods1 & pass into "o ano!r by ! mo/ ins5sible gradations4 ,we mu/ n[ proce$ to comp>e ! gr& & t]rible appe>ances pres5t$ dur+ a great eruption ) ^? m feeble displays :i* we h be5 describ+1 to %[ t 9 all _! ess5tial features ^! diff]5t k9ds ( outbur/s are id5tical ) "o ano!r1 & mu/ be ref]r$ to ! action ( simil> causes4 ,! volcanic eruption :i* has be5 mo/ c>efully /udi$ 9 rec5t times is t :i* we h already ref]r$ to z occurr+ at ,vesuvius1 9 ! mon? ( ,april #ahgb4 ,) ! exception1 p]haps1 ( t :i* took place 9 ,octob] #ahbb1 ?is eruption 0 ! gr&e/ :i* has brok5 out at ,vesuvius dur+ ! pres5t c5tury4 ,ow+ to ! circum/ance ( its proximity to ! great city ( ,naples1 ,vesuvius has always be5 ! mo/ c>efully wat*$ ( all volcanoes1 & 9 rec5t ye>s ! erection ( an obs]vatory1 provid$ ) in/rum5ts = record+ ! smalle/ subt]ranean tremors affect+ ! m\nta91 has facilitat$ ! c>ry+ on ( ^? cont9u\s & m9ute obs]vations :i* are s necess>y = exact sci5tific inquiry4 ,illu/ration3 ,fig #e4 ,vesuvius 9 ,eruption1 z se5 f ,naples1 ,april #bf1 #ahgb4 7,f a photograph7 ,sid5ote3 ,,vesuvius ,,eruption ,,( #ahgb4 ,on ! occasion ( ?is outbur/1 ! aid ( in/antane\s photography 0 fir/ made available = obta9+ a p]man5t record ( ! appe>ances display$ at volcanic eruptions4 ,9 fig4 #e we h "o ( ^! photographs1 :i* 0 tak5 at #e o'clock ,p4,m4 on ,april #bf1 #ahgb1 transf]r$ to a wood-block & engrav$4 ,9 exam9+ x we feel sure t we are n be+ misl$ by any exagg]ation or error on ! "p ( ! arti/4 ,vesuvius rises to ! height ( ne>ly #d1jjj feet above ! level ( ! sea1 & an inspection ( ! photograph proves t ! vap\rs & rock-fragm5ts 7 ?r[n to ! enorm\s height ( #bj1jjj feet1 or ne>ly f\r miles1 into ! atmosph]e4 ,! ma9 features ( ?is t]rify+ outbur/ 7 z foll[s4 ,= m ?an a twelvemon? be=e1 ! activity ( ! =ces at "w )9 ! m\nta9 appe>$ to be gradually increas+1 & ! great eruption comm5c$ on ,april #bd1 atta9$ its climax on ! #bf?1 & began to die out on ! foll[+ day4 ,dur+ ! eruption ! bottom ( ! crat] 0 entirely brok5 up1 & ! sides ( ! m\nta9 7 r5t by fissures 9 all directions4 ,s num]\s 7 ^! fissures & cracks t liquid matt] appe>$ to be ooz+ f e "p ( its surface1 &1 z ,pr(essor ,palmi]i1 :o witness$ ! outbur/ f ! obs]vatory1 express$ x1 ',vesuvius sweat$ fire4' ,"o ( ! fissures 0 ( enorm\s size1 ext5d+ f ! summit to f> beyond ! base ( ! cone2 ! sc> left by ?is gigantic r5t be+ pla9ly visible at ! pres5t day4 ,f ! great op5+ or crat] at ! summit1 & f "s ( ! fissures on ! sides ( ! m\nta91 enorm\s volumes ( /eam ru%$ out ) a prodigi\s ro>+ s\nd1 ! noise be+ s t]rific t ! inhabitants ( ,naples1 five miles (f1 fl$ f _! h\ses & sp5t ! night 9 ! op5 /reets4 ,al?\gh ?is ro>+ s\nd appe>$ at a di/ance to be cont9u\s1 yet ^? ^u ! m\nta9 c\ld p]ceive t x 0 produc$ by detonations or explosions rapidly foll[+ "o ano!r4 ,ea* ( ^! explosions 0 accompani$ by ! =mation ( a great globe ( :ite vap\r1 :i*1 ris+ into ! atmosph]e1 swell$ ! bulk ( ! va/ cl\d ov]hang+ ! m\nta94 ,an inspection ( ! photographs 7see fig4 #e7 %[s t ! great vap\r-cl\d ov] ,vesuvius 0 made up ( ! globul> masses eject$ at successive explosions4 ,ea* ( ^! explosive upw>d ru%es ( /eam c>ri$ along ) x a consid]able quantity ( solid fragm5ts1 & ^! fell 9 great numb]s all ov] ! surface ( ! m\nta91 break+ ! w9d[s ( ! obs]vatory1 & mak+ x dang]\s to be out ( doors4 ,we h said t lava1 or molt5 rock1 appe>$ to be issu+ f ! v num]\s cracks =m$ all ov] ! flanks ( ! m\nta94 ,b at ?ree po9ts ?is molt5 rock issu$ 9 su* quantities z to =m great1 fi]y floods1 :i* ru%$ d[n ! sides ( ! m\nta91 & fl[$ to a consid]able di/ance beyond its base4 ,! l>ge/ ( ^! lava-floods ov]:elm$ & de/roy$ ! two villages ( ,massa di ,somma & ,san ,seba/iano1 besides _m c\ntry h\ses 9 ! neighb\rhood4 ,sid5ote3 ,,/eam ,,emitt$ ,,f ,,lava-,,curr5t4 ,a v m>k$ & int]e/+ feature exhibit$ by ^! ?ree lava-floods 0 ! quantity ( wat]y vap\r :i* !y gave (f dur+ _! fl[4 ,all along _! c\rse1 enorm\s volumes ( /eam 7 evolv$ f !m1 z w be se5 by an inspection ( ! photograph4 ,inde$1 su* 0 ! abundance & t5sion ( ! /eam ?us escap+ f ! surfaces ( ! lava-curr5ts t x =c$ ! congeal+ rock up into great bubbles & bli/]s1 & gave rise to ! =mation ( innum]able m9iature volcanoes1 v>y+ 9 size f a beehive to a cottage1 "s ( :i* rema9$ 9 a /ate ( indep5d5t activity = a consid]able "t4 ,s f>1 :at we h describ$ z tak+ place at ,vesuvius1 9 ,april #ahgb1 has be5 only ! repetition on a ,eur gr&] scale ( ! ?ree k9ds ( action :i* we h %[n to be con/antly tak+ place at ,/romboli2 namely1 ! =mation ( cracks or fissures 9 ! e>?'s surface1 ! escape ( /eam ) explosive viol5ce f ^! op5+s1 (t5 propell+ rock-fragm5ts into ! atmosph]e1 & ! outwell+1 "u ! influ5ce ( ?is compress$ /eam1 ( masses ( molt5 mat]ials4 ,!re 7 "s o!r appe>ances pres5t$ at ! great outbur/ at ,vesuvius1 :i* d n seem at fir/ sight to f9d any analogies 9 ! manife/ations ( ! m feeble action cont9ually go+ on at ,/romboli4 ,be=e & dur+ ! great outbreak ( ,april #ahgb1 ,vesuvius itself & ! :ole c\ntry r\nd 7 visit$ ) e>?quake-%ocks1 or trembl+s ( ! gr\nd4 ,! s5sitive in/rum5ts 9 ! ,vesuvian ,obs]vatory %[$ ! m\nta9 d>+ ! eruption to be 9 a con/ant /ate ( tremor4 ,^! e>?quakes are n1 z is commonly suppos$1 actual upheav+s ( ! e>?'s surface1 b are vibrations propagat$ ?r\gh ! solid mat]ials ( :i* ! e>? is built up4 ,we _c /amp our feet ^u ! gr\nd )\t giv+ rise to su* vibrations1 ?\gh our s5ses may n be suffici5tly acute to p]ceive !m4 ,! explosive escape ( /eam f a crack is a cause suffici5tly p[]ful to produce a %ock :i* is propagat$ & may be felt = a consid]able di/ance r\nd4 ,ev5 on ,/romboli an obs]v] at ! edge ( ! crat] may notice t ea* explosive outbur/ ( /eam is accompani$ by a p]ceptible tremor ( ! gr\nd1 & 9 ! case ( ,vesuvius ! viol5t %ocks produc$ by ! escape ( f> l>g] volumes ( /eam give rise to proportionately /rong] vibrations4 ,! nature & orig9 ( ^? f> m t]rible & de/ructive %ocks :i* sometimes accompany1 & m frequ5tly prec$e1 great volcanic eruptions1 we %all consid] 9 ! sequel4 ,sid5ote3 ,,cause ,,( ,,lightn+ ,,dur+ ,,eruptions4 ,ano!r /rik+ ph5om5on :i* 0 exhibit$ 9 ! great eruption ( ,vesuvius 9 #ahgb 0 ! vivid display ( lightn+ accompani$ by ?und]4 ,! upru%+ curr5t ( /eam & rock-fragm5ts =ms a v]tical column1 b z ! /eam cond5ses x spreads out into a great horizontal cl\d :i* is se5 to be made up ( ! great globes ( vap\r emitt$ at successive explosions4 ,:5 !re is little or no w9d ! v]tical column ) a horizontal cl\d above x be>s a /rik+ resemblance to ! /one-p9e trees :i* =m s conspicu\s a feature 9 e ,neapolitan l&scape4 ,ar\nd ?is column ( vap\r ! mo/ vivid lightn+ con/antly plays & adds n a little to ! gr& & awful "* ( ! spectacle ( a volcanic eruption1 especially :5 x is view$ by night4 ,9 ! eruption ( #ahgb a /rong w9d bl[+ f ! nor?-we/ de/roy$ ! usual regul> appe>ance ( ?is 'p9e-tree app5dage' to ! m\nta91 :i* is s well kn[n to1 & dread$ by ! inhabitants ( ,naples2 ! cl\d1 z w be se5 f ! photograph 7fig4 #e1 fac+ p4 #bd71 0 bl[n on "o side1 & mo/ ( ! fall+ fragm5ts took ! same direction4 ,x is well kn[n t :5 high-pressure /eam is all[$ to escape ?r\gh an orifice1 electricity is abundantly g5]at$ by ! friction1 & ,sir ,william ,arm/rong's hydro-electric ma*9e is con/ruct$ on ?is pr9ciple4 ,e volcano 9 viol5t eruption is a v effici5t hydro-electric ma*9e1 & ! upru%+ column is 9 a condition ( int5se electrical excitation4 ,?is result is probably aid$ by ! friction ( ! solid p>ticles z !y are propell$ upw>ds & fall back into ! crat]4 ,! re/oration ( ! condition ( electrical /ability betwe5 ?is column & ! surr\nd+ atmosph]e is att5d$ ) ! production ( frequ5t lightn+-fla%es & ?und]-claps1 ! f\nd ( ! latt] be+ usually1 h[ev]1 dr[n$ 9 ! /ill l\d] ro> ( ! upru%+ /eam-column4 ,! dis*>ge ( ,bu* l>ge quantities ( /eam into ! atmosph]e soon causes ! latt] to be saturat$ ) wat]y vap\r1 & !re foll[s an excessive ra9fall2 long-cont9u$ ra9 & floods 7 an accompanim5t ( ! great ,vesuvian outbreak ( #ahgb1 z !y h be5 ( almo/ all great volcanic eruptions4 ,! ,italians1 inde$1 dread ! floods :i* foll[ an eruption m ?an ! fi]y /reams ( lava :i* accompany x--= !y h f\nd ! mud-/reams 7lave di fango71 =m$ by ra9-wat] sweep+ along ! loose volcanic mat]ials1 to be m widely de/ructive 9 _! effects ?an ! curr5ts ( molt5 rock 7lave di fuoco74 ,besides ! ph5om5a :i* we h n[ describ$ z accompany+ a great volcanic outbur/1 _m o!rs h und\bt$ly be5 record$ by app>5tly tru/wor?y au?orities4 ,b1 9 deal+ ) ! descriptions ( ^! gr& & t]rible ev5ts1 we mu/ always be on our gu>d aga9/ accept+ z lit]al facts1 ! /atem5ts made by witnesses1 (t5 writ+ at "s di/ance f ! sc5e ( action1 & almo/ always "u ! influ5ce ( viol5t excitem5t & t]ror4 ,! desire to adm9i/] to ! univ]sal love ( ! m>vell\s1 & ! t5d5cy to exagg]ation1 w usually acc\nt = _m ( ! wond]ful /atem5ts conta9$ 9 su* records2 &1 ev5 :]e ! witness is accurately relat+ ev5ts :i* he ?9ks pass$ be=e 8 eyes1 we mu/ rememb] t x is probable he may h _h nei!r ! opportunity nor ! capacity = exact obs]vation4 ,! m c>efully we sift ! acc\nts :i* h be5 pres]v$ ( great volcanic outbur/s1 ! m are we /ruck by ! fact t ! appe>ances describ$ c be resolv$ into a few simple op]ations1 ! true "* ( :i* has be5 di/ort$ or disguis$ by ! want ( accurate obs]vation on ! "p ( ! witnesses4 ,sid5ote3 ,,simil>ity ,,( ,,feeble ,,& ,,viol5t ,,eruptions4 ,we are ?us l$ to ! conclusion t ! gr& & t]rible appe>ances display$ at ,vesuvius & o!r volcanoes 9 a /ate ( viol5t eruption d n diff] 9 any ess5tial respect f ! ph5om5a :i* we h witness$ accompany+ ! m9iature outbur/s ( ,/romboli4 ,& we are conv9c$1 by ! same consid]ations1 t ! =ces :i* give rise to ! feeble displays 9 ! latt] case w\ld produce1 if act+ ) great] int5sity & viol5ce1 all ! magnific5t spectacles pres5t$ 9 ! =m]4 ,9 ,vesuvius & ,/romboli alike1 ! active cause ( all ! ph5om5a exhibit$ is f\nd to be ! escape ( /eam f ! mid/ ( masses ( inc&esc5t liquefi$ rock4 ,! viol5ce1 & !re=e ! gr&eur & de/ructive effects ( an eruption1 dep5d ^u ! abundance & t5sion ( ?is escap+ /eam4 ,!re is "o respect 9 :i* volcanic ph5om5a are especially calculat$ to excite ! fe> & wond] ( behold]s--namely1 9 ! sudd5 & app>5tly spontane\s "* ( _! manife/ations4 ,eclipses 7 reg>d$ z equally port5t\s ) volcanic eruptions till a/ronom]s le>n$ n only to expla9 ! causes :i* gave rise to !m1 b ev5 to pr$ict to ! second ! times ( _! occurr5ce4 ,if we 7 able 9 l mann] to w>n ! inhabitants ( volcanic regions ( ! approa* ( a gr& eruption1 ! fe> & sup]/ition ) :i* ^! ev5ts are n[ reg>d$ w\ld d\btless be 9 great "p dispell$4 ,! p[] ( pr$iction is alike ! crucial te/ & ! cr[n+ triumph ( a sci5tific !ory4 ,b1 al?\gh natural philosoph]s are able to assign ! causes to :i* ! gr& op]ations ( volcanoes are due1 & also to expla9 all ! v>i$ appe>ances :i* accompany !m1 !y h n z yet s f> ma/]$ ! laws :i* gov]n volcanic action z to be able to pr$ict ! p]iods ( _! manife/ation4 ,t ^! op]ations1 l all o!rs go+ on ^u ! globe1 are gov]n$ by great natural laws we _c = a mom5t d\bt4 ,& t1 9 all probability1 m c>eful & exact obs]vation & reason+ w at "s future "t lead u to ! recognition ( ^! laws1 e /ud5t ( nature is sangu9e4 ,b at ! pres5t "t1 x mu/ be confess$1 we are v f> inde$ f be+ able to af=d t cr[n+ pro( ( ! tru? ( our !ories ( volcanic action :i* is impli$ 9 ! p[] ( pr$ict+ ! p]iod & degree ( int5sity ( _! manife/ations4 ,sid5ote3 ,,eruptions ,,& ,,! ,,int]vals ,,betwe5 ,,!m4 ,!re are1 h[ev]1 "s obs]vations :i* lead u to hope t ! "t may n be f> di/ant :5 we %all h s ,eur obta9$ a k ( ! conditions on :i* volcanic action dep5ds z to be able to =m "s judgm5t z to its manife/ations 9 ! future at any p>ticul> locality4 ,b we mu/ recollect t ^! conditions axe v num]\s & complicat$1 & t "s ( !m may lie almo/ entirely outside our sph]e ( obs]vation2 h5ce ha/y attempts 9 ?is direction1 su* z h rec5tly be5 made1 are to be deprecat$ by e true lov] ( sci5ce4 ,conc]n+ ! eruptions t h tak5 place at ^? volcanic c5tres :i* h be5 kn[n f a remote antiquity1 we h records f :i* we c det]m9e ! int]vals sep>at+ ^! outbur/s & _! relative viol5ce4 ,a critical exam9ation ( ^! records leads to ! foll[+ conclusions3-- 7#a47 ,a long p]iod ( quiesc5ce is g5]ally foll[$ by an eruption :i* is ei!r ( long duration or ( great viol5ce4 7#b47 ,a long-cont9u$1 or v viol5t eruption is usually foll[$ by a prolong$ p]iod ( repose4 7#c47 ,feeble & %ort eruptions usually succe$ "o ano!r at brief int]vals4 7#d47 ,z a g5]al rule1 ! viol5ce ( a great eruption is inv]sely proportional to its duration4 ,x w be se5 t ^! g5]al conclusions are 9 p]fect h>mony ) ! !ory t volcanic outbur/s are due to ! accumulation ( /eam at volcanic c5tres1 & t ! t5sion ( ?is imprison$ gas ev5tually ov]comes ! repress+ =ces :i* t5d to prev5t its manife/ation4 ,be=e a/ronom]s _h le>nt to det]m9e all ! conditions on :i* ! production ( eclipses dep5ds1 !y _h f\nd t ^! ph5om5a succe$ "o ano!r at regul> int]vals4 ,! discov]y ( su* a/ronomical cycles 0 a great advance 9 our k ( ! heav5ly bodies1 & 9 ! same way ! det]m9ation ( ^! g5]al relations betwe5 ! int5sity & duration ( volcanic outbur/s & ! int]vals ( "t :i* sep>ate !m may be reg>d$ z ! fir/ /ep t[>ds ! discov]y ( ! laws :i* gov]n volcanic activity4 ,9 ! actual det]m9ation ( ! conditions ^u :i* ! occurr5ce ( volcanic eruptions dep5ds1 x mu/ be confess$1 h[ev]1 t v little has z yet be5 done4 ,?is is 9 "p due to ! fact t "s at lea/ ( ^! conditions lie beyond ! limits ( direct obs]vation4 ,b x mu/ also be admitt$1 on ! o!r h&1 t little has be5 z yet accompli%$ t[>ds ! c>eful & sy/ematic obs]vation ( ^? ph5om5a :i* may1 & probably d1 ex]t an influ5ce 9 br++ ab\t volcanic outbur/s4 ,sid5ote3 ,,influ5ce ,,( ,,atmosph]ic ,,conditions4 ,9 ! ,lip>i ,isl&s !re has prevail$ a belief1 f ! v e>lie/ p]iod ( hi/ory1 t ! feeble eruptions ( ,/romboli are 9 "s way dep5d5t ^u ! condition ( ! atmosph]e4 ,^! isl&s 7 kn[n to ! anci5ts z ! olian ,isles1 f ! fact t !y 7 once rul$ ov] by a k+ ( ! "n ( olus4 ,x seems n improbable t olus 0 gift$ ) natural p[]s ( obs]vation & reason+ f> 9 advance ( ^? ( 8 contempor>ies4 ,a c>eful /udy ( ! vap\r-cl\d :i* cov]s ,/romboli w\ld c]ta9ly af=d him in=mation conc]n+ ! hygrometric condition ( ! atmosph]e2 ! =m & position assum$ by ?is vap\r-cl\d w\ld be a no less p]fect index ( ! direction & =ce ( ! w9d2 &1 if ! popul> belief be well f\nd$1 ! frequ5ce & viol5ce ( ! explosions tak+ place f ! crat] w\ld indicate ! b>ometric pressure4 ,f ^! data an acute obs]v] w\ld be able to issue '/orm-w>n+s' & wea!r-progno/ics ( consid]able value4 ,9 ! vulg> m9d1 ! idea ( ! pr$iction ( natural ev5ts is closely b\nd up ) t ( _! production2 & ! %rewd wea!r-prophet ( ,lip>i 0 aft] 8 dea? rais$ to ! rank ( a god1 & inve/$ ) ! sov]eignty ( ! w9ds4 ,:e!r ! popul> idea t ! outbur/s ( ,/romboli are regulat$ by atmosph]ic conditions has any f\ndation is /ill op5 to grave d\bt4 ,x seems to be c]ta91 h[ev]1 t dur+ autumn & w9t] ! m viol5t p>oxysms ( ! volcano occur1 & t 9 summ] ! action :i* takes place is f> m regul> & equable4 ,x w\ld be ( ! greate/ b5efit to sci5ce if an obs]vatory 7 erect$ beside ! crat] ( ,/romboli1 :]e a c>eful record might be kept ( all atmosph]ic *anges1 & ( ! syn*ron\s manife/ations ( ! volcanic =ces4 ,a little consid]ation w %[ t x is a by no means unreasonable supposition t v>iations 9 atmosph]ic pressure may ex]cise a v important influ5ce 9 br++ ab\t volcanic outbur/s4 ,*anges 9 ! b>omet] to ! ext5t ( two in*es )9 a v %ort p]iod are n uncommon occurr5ces4 ,a v simple calculation w %[ t ! fall ( ! m]cury 9 ! b>omet] to ! ext5t ( two in*es indicates ! removal ( a weight ( two millions ( tons f ea* squ>e mile ( ! e>?'s surface :]e ?is *ange takes place4 ,n[1 if we suppose1 z we h good gr\nd = do+1 t "u volcanic areas va/ quantities ( sup]heat$ wat] are only prev5t$ f fla%+ into /eam by ! sup]9cumb5t pressure1 a relief ( ?is pressure to ! ext5t ( two millions ( tons on e squ>e mile c\ld sc>cely fail to produce v m>k$ effects4 ,! way 9 :i* explosions 9 fi]y coal-m9es g5]ally foll[ closely ^u sudd5 falls 9 ! atmosph]ic pressure is n[ well kn[n2 & coal-m9e explosions & volcanic outbur/s h ?is 9 common1 t bo? result f ! sudd5 & viol5t lib]ation ( subt]ranean gases4 ,!re are n a few app>5tly well-au!nticat$ acc\nts ( volcanic & e>?quake ph5om5a foll[+ closely on peculi> atmosph]ic conditions1 & ! :ole "q ( ! relation ( ! volcanic =ces to atmosph]ic pressure1 z ,spallanzani himself s long ago po9t$ out1 is des]v+ ( a mo/ c>eful & rigor\s inve/igation4 ,sid5ote3 ,,suppos$ ,,tidal ,,effects4 ,!re is "o o!r consid]ation :i* has frequ5tly be5 urg$ z wor?y ( especial att5tion1 9 deal+ ) ! "q ( ! excit+ causes ( volcanic outbur/s4 ,if volcanoes 71 z 0 at "o "t almo/ univ]sally suppos$1 9 direct communication ) a great c5tral mass ( liquefi$ mat]ials1 or ev5 if any l>ge res]voirs ( su* liquids exi/$ b5ea? volcanic di/ricts1 z o!rs h imag9$1 !n ! diff]5t mobility ( ! solid & liquid portions ( ! e>?'s mass w\ld give rise to tidal effects simil> to ^? occurr+ 9 ! surface wat]s ( ! globe4 ,"u su* circum/ances1 volcanic outbur/s1 l ! tides1 w\ld be det]m9$ by ! relative positions ( ! sun & moon to our globe4 ,x is c]ta91 h[ev]1 t no v direct relation has yet be5 e/abli%$ betwe5 ! lun> p]iods & ^? ( volcanic outbur/s1 ?\gh rec5t close obs]vations ^u ! crat] ( ,vesuvius1 by ,pr(essor ,palmi]i1 d seem to l5d support to ! view t su* relations may exi/4 ,at ! pres5t "t1 !re=e1 x mu/ be admitt$ t vulcanologi/s h only j comm5c$ ^? s]ies ( exact & cont9u\s obs]vations :i* are necess>y to det]m9e ! conditions t regulate ! appe>ance ( volcanic ph5om5a4 ,! /udy ( ! laws ( volcanic action is yet 9 its infancy4 ,b ! e/abli%m5t ( obs]vatories on ,vesuvius & ,etna #ah fall ( promise = ! future1 & :5 we consid] ! advances :i* h be5 made1 dur+ ! la/ "o hundr$ ye>s1 9 our k ( ! true nature ( volcanic action1 we ne$ n despair t ! ext5sion ( ! same me?ods ( inquiry w lead to equally important results conc]n+ ! conditions :i* det]m9e & ! laws :i* gov]n x4 ,9 ! mean:ile1 x is no small ga9 to h e/abli%$ ! fact t volcanic ph5om5a1 dive/$ ( all ^? wond]ful attributes ) :i* sup]/ition & ! love ( ! m>vell\s h surr\nd$ !m1 are op]ations ( nature obey+ def9ite laws1 :i* laws we may hope by c>eful obs]vation & accurate reason+ to det]m9e2 & t ! v>i$ appe>ances1 pres5t$ alike 9 ! gr&e/ & feeble/ outbur/s1 c all be ref]r$ to "o simple cause--namely1 ! escape1 f ! mid/ ( masses ( molt5 mat]ials1 ( imprison$ /eam or wat]-gas4 ,,*apt] ,,iii4 ,,! ,,products ,,( ,,volcanic ,,action4 ,:ile ,spallanzani 0 engag$ 9 inve/igat+ ! nature ( ! action go+ on at ,/romboli & o!r ,italian volcanoes1 8 contempor>y ,dolomieu 0 lay+ ! f\ndation ( ano!r important bran* ( vulcanology by /udy+ ! *>act]s ( ! diff]5t mat]ials ( :i* volcanoes are built up4 ,s9ce ! publication ( ,dolomieu's admirable works on ! rocks ( ! ,lip>i & ,ponza ,isl&s1 sci5ce has advanc$ ) prodigi\s /rides4 ,! *emi/ has taught u h[ to split up a rock into its con/itu5t elem5ts & to det]m9e ! proportions ( ^! to "o ano!r ) ma!matical precision2 ! m9]alogi/ has done mu* 9 ! inve/igation ( ! *>act]s & mode ( orig9 ( ! cry/all9e m9]als :i* occur 9 ^! rocks2 & ! microscopi/ has %[n h[ ! m9ute int]nal /ructure ( ^! rocks may be made cle>ly manife/4 ,we %all proce$ to give a sket* ( ! pres5t /ate ( k obta9$ by ^! diff]5t k9ds ( inve/igations1 conc]n+ ! mat]ials :i* are eject$ f volcanic v5ts4 ,! mo/ abundant ( ! sub/ances :i* are eject$ f volcanoes is /eam or wat]-gas1 :i*1 z we h se51 issues 9 prodigi\s quantities dur+ e eruption4 ,b ) ! /eam a great numb] ( o!r volatile mat]ials frequ5tly make _! appe>ance4 ,! *ief among ^! are ! add gases kn[n z hydro*loric acid1 sulphur\s acid1 sulphurett$ hydrog51 c>bonic add1 & boracic acid2 & ) ^! acid gases !re issue hydrog51 nitrog51 ammonia1 ! volatile metals ars5ic1 antimony1 & m]cury1 & "s o!r sub/ances4 ,9 consid]+ ! nature ( ! products :i* issue f volcanic fissures1 x mu/ be rememb]$ t _m sub/ances :i* "u ord9>y circum/ances d n exhibit m>k$ volatility are nev]!less easily c>ri$ away 9 f9e p>ticles :5 a curr5t ( /eam is pass$ ov] !m4 ,z we %all h to po9t out 9 ! sequel1 diff]5t volatile sub/ances h a t5d5cy to make _! appe>ance at volcanic v5ts accord+ z ! int5sity ( ! action go+ on )9 x v>ies4 ,! volatile sub/ances issu+ f volcanic fissures at high temp]atures react ^u "o ano!r1 & _m new comp\nds are ?us =m$4 ,we h already se5 h[1 by ! action ( sulphur\s acid & sulphurett$ hydrog5 on ea* o!r1 ! sulphur s common 9 volcanic di/ricts has be5 sep>at$ & deposit$4 ,! hydro*loric acid acts v en]getically on ! rocks ar\nd ! v5ts1 unit+ ) ! iron 9 !m to =m ! yell[ f]ric-*loride4 ,! rocks all r\nd a volcanic v5t are n unfrequ5tly f\nd coat$ ) ?is yell[ sub/ance1 :i* is almo/ always mi/ak5 by casual obs]v]s = sulphur4 ,9 _m volcanoes ! con/ant passage ?r\gh ! rocks ( ! v>i\s acid gases has caus$ ne>ly ! :ole ( ! iron1 lime1 & alkal9e mat]ials ( ! rocks to be conv]t$ into soluble comp\nds kn[n z sulphates1 *lorides1 c>bonates1 & borates2 &1 on ! removal ( ^! by ! ra91 !re rema9s a :ite1 p[d]y sub/ance1 resembl+ *alk 9 outw>d appe>ance1 b compos$ ( almo/ pure silica4 ,!re are c]ta9 cases 9 :i* travell]s h visit$ volcanic isl&s :]e *emical action ( ?is k9d has gone on to su* an ext5t1 t !y h be5 l$ to describe ! isl&s z compos$ entirely ( *alk4 ,sid5ote3 ,,gases ,,emitt$ ,,f ,,volcanoes4 ,"s ( ! sub/ances issu+ f volcanic v5ts1 su* z hydrog5 & sulphurett$ hydrog51 are inflammable1 & :5 !y issue at a high temp]ature1 ^! gases bur/ into flame ! mom5t t !y come into contact ) ! air4 ,h5ce1 :5 volcanic fissures axe wat*$ at night1 fa9t lamb5t flames are frequ5tly se5 play+ ov] !m1 & sometimes ^! flames are brilliantly col\r$1 ?r\gh ! pres5ce ( small quantities ( c]ta9 metallic oxides4 ,su* volcanic flames1 h[ev]1 are sc>cely ev] /rongly lum9\s &1 z we h already se51 ! r$1 gl[+ light :i* is obs]v$ ov] volcanic m\nta9s 9 eruption is due to q ano!r cause4 ,! /udy by ! aid ( ! spectroscope ( ! flames :i* issue f volcanic v5ts promises to ?r[ mu* new light on ! r>] mat]ials eject$ by volcanoes4 ,spectroscopic obs]vations ( ?is k9d h already be5 comm5c$ by ,janss51 at ,/romboli & ,santor94 ,"s ( ! volatile sub/ances issu+ f volcanic v5ts1 are at once deposit$ :5 !y come 9 contact ) ! cool atmosph]e1 o!rs =m new comp\nds ) "o ano!r & ! con/itu5ts ( ! atmosph]e1 :ile o!rs aga9 attack ! mat]ials ( ! surr\nd+ rocks & =m fre% *emical comp\nds ) "s ( _! +r$i5ts4 ,?us1 !re are cont9ually accumulat+ on ! sides & lips ( volcanic fissures deposits ( sulphates1 *lorides1 & borates ( ! alkalies & alkal9e e>?s1 ) sal-ammoniac1 sulphur1 & ! oxides & sulphides ( c]ta9 metals4 ,! lips ( ! fissures f :i* /eam & acid gases issue 9 volcanoes are con/antly se5 to be coat$ ) yell[ & r$di%-br[n incru/ations1 consi/+ ( mixtures1 9 v>y+ proportions1 ( ^! diff]5t mat]ials1 & ^! sometimes assume ! =m ( /alactites & p5d5t masses4 ,sid5ote3 ,,deposits ,,ar\nd ,,volcanic ,,v5ts4 ,"s ( ^! products ( volcanic action are ( consid]able comm]cial value4 ,at ,vulcano regul> *emical works h be5 e/abli%$ 9 ! crat] ( ! volcano1 by an ent]pris+ ,scot* firm1 a great numb] ( workm5 be+ engag$ 9 collect+ ! mat]ials :i* are deposit$ ar\nd ! fissures1 & are r5ew$ by ! volcanic action almo/ z soon z !y are remov$4 ,9 fig4 #f1 ,i h giv5 a sket* ( ?is s+ul> spot1 tak5 f ! high gr\nd ( ! neighb\r+ ,isl& ( ,lip>i4 ,f ! village at ! foot ( ! volcano1 :]e ! workm5 live1 a zig-zag road has be5 con/ruct$ lead+ up ! side1 & d[n into ! crat] ( ! volcano4 ,on ?is road1 workm5 & mules1 lad5 ) ! v>i\s volcanic mat]ials1 may be se5 con/antly pass+ up & d[n4 ,illu/ration3 ,fig4 #f4--,view ( ,vulcano1 ) ,vulcanello 9 ! =egr\nd tak5 f ! s\? end ( ! ,isl& ( ,lip>i4 ,vulcano appe>s to h be5 frequ5tly 9 a /ate ( viol5t eruption dur+ ! pa/ #b1jjj ye>s--! la/ great outbur/ hav+ tak5 place 9 #aghf4 ,9 #ahgc ! activity 9 ! crat] ( ,vulcano sudd5ly became m pron\nc$ 9 "*1 & ! workm5 ha/5$ to escape f ! dang]\s spot1 b1 be=e !y c\ld d s1 sev]al ( !m 7 sev]ely injur$ by ! explosions4 ,aft] ?is outbur/1 :i* did n prove to be ( v viol5t "*1 ! quantity ( gases issu+ f ! fissures 9 ! crat] 0 = a "t mu* great] ?an be=e1 & ! productiv5ess ( ^! great natural *emical works 0 proportionately increas$3 b ev5tually ! action di$ out almo/ entirely4 ,! *ief products ( ,vulcano :i* are ( comm]cial value1 are sal-ammoniac1 sulphur1 & boracic acid4 ,at "o "t x 0 ev5 contemplat$ t great lead5 *amb]s %\ld be erect$ ov] ! pr9cipal fissures at ! bottom ( ! crat] ( ,vulcano1 9 :i* *amb]s ! volatile mat]ials might be cond5s$ & collect$4 ,! *ange 9 ! condition ( ! volcano has un=tunately prev5t$ ! c>ry+ out ( ?is bold project4 ,besides ! volatile sub/ances :i* issue f volcanic v5ts1 m+l+ ) ! atmosph]e or cond5s+ ^u _! sides1 !re are also _m solid mat]ials eject$1 & ^! may accumulate ar\nd ! orifices1 till !y build up m\nta9s ( va/ dim5sions1 l ,etna1 ,t5]iffe1 & ,*imborazo4 ,"s ( ^! solid mat]ials are evid5tly fragm5ts ( ! rock-masses1 ?r\gh :i* ! volcanic fissure has be5 r5t2 ^! fragm5ts h be5 c>ri$ upw>ds by ! =ce ( ! /eam-bla/ & scatt]$ ov] ! sides ( ! volcano4 ,b ! pr9cipal portion ( ! solid mat]ials eject$ f volcanic orifices consi/s ( matt] :i* has be5 extrud$ f s\rces f> b5ea? ! surface1 9 a highly-heat$ & fluid or semi-fluid condition4 ,sid5ote3 ,,eject$ ,,rock-,,fragm5ts4 ,! fragm5ts torn f ! sides ( volcanic fissures consi/ ( ! rocks ?r\gh :i* ! eruptive =ces may happ5 to h op5$ _! way2 pieces ( s&/one1 lime/one1 slate1 granite1 c41 are ?us frequ5tly f\nd 9 consid]able numb]s among mat]ials :i* build up volcanic m\nta9s4 ,?us1 "s ( ! volcanic cones 9 ! ,eifel are v l>gely made up ( fragm5ts ( slate1 :i* h be5 torn f ! sides ( ! v5ts by ! upru%+ curr5ts ( /eam4 ,at ,vesuvius masses ( lime/one are frequ5tly eject$1 & may be pick$ up all ov] ! slopes ( ! m\nta9s4 ,^! lime/one-fragm5ts frequ5tly conta9 fossils1 & ,pr(essor ,guisc>di1 ( ,naples1 has be5 able to collect sev]al hundr$ species ( %ells1 transport$ ?us by volcanic action f ! rock-masses :i* =m ! f\ndation ( ! volcano ( ,vesuvius4 ,! action ( wat] at a high temp]ature1 & "u su* enorm\s pressure z mu/ exi/ b5ea? volcanic m\nta9s1 has (t5 produc$ *anges 9 ! rocks ( :i* fragm5ts are eject$ f volcanic v5ts4 ,! s-call$ 'lava' ornam5ts1 :i* are s ext5sively sold at ,naples1 are n made f ! mat]ials to :i* geologi/s apply t "n1 b f ! fragm5ts ( alt]$ lime/one t h be5 torn f ! rocks b5ea? ! m\nta91 & scatt]$ by ! eruptive =ces all ov] its sides4 ,! *emical action ( ! sup]heat$ & highly-compress$ /eam on ! rocks b5ea? volcanoes frequ5tly results 9 ! =mation ( beautifully cry/allis$ m9]als4 ,su* cry/allis$ m9]als ab\nd 9 ! rock-fragm5ts scatt]$ ov] ! sides ( ,vesuvius & o!r volcanoes1 bo? active & ext9ct4 ,!y h be5 =m$ 9 ! great *emical laboratories :i* exi/ b5ea? ! volcano1 & h be5 br\ght to ! surface by ! action ( ! /eam-jets issu+ f its fissures4 ,( /ill great] int]e/ are ^? mat]ials :i* issue f volcanic orifices 9 an inc&esc5t1 & (t5 9 a molt51 condition1 & :i* are evid5tly d]iv$ f s\rces f> bel[ ! e>?'s surface4 ,x is to ^! mat]ials t ! "n ( 'lavas' is prop]ly appli$4 ,lavas pres5t a g5]al resemblance to ! slags & cl9k]s :i* are =m$ 9 our furnaces & brick-kilns1 & consi/1 l !m1 ( v>i\s /ony sub/ances :i* h be5 m or less p]fectly fus$4 ,:5 we come to /udy ! *emical composition & ! microscopical /ructure ( lavas1 h[ev]1 we %all f9d t !re are _m respects 9 :i* !y diff] entirely f ^! artificial products4 ,let u fir/ consid] ! facts :i* are taught u conc]n+ ! nature & orig9 ( lavas1 by a *emical analysis ( !m4 ,sid5ote3 ,,*emical ,,composition ,,( ,,lavas4 ,( ! sixty-five or sev5ty *emical elem5ts1 only a v small numb] occur at all commonly 9 lavas4 ,eight elem5ts1 inde$1 make up ! great mass ( all lavas--^! are oxyg51 silicon1 alum9ium1 magnesium1 calcium1 iron1 sodium1 & potassium4 ,b ev5 ^! eight elem5ts are pres5t 9 v unequal proportions4 ,oxyg5 makes up ne>ly "o-half ! weight ( all lavas4 ,almo/ all ! o!r elem5ts f\nd 9 lavas exi/ 9 comb9ation ) oxyg51 s t lavas consi/ entirely ( :at *emi/s call 'oxides4' ,?is is a mo/ rem>kable circum/ance1 :i*1 z we %all pres5tly see1 is ( great significance4 ,! metalloid silicon makes up ab\t "o-f\r? ( ! weight ( mo/ lavas1 & ! metal alum9ium ab\t "o-t5?4 ,! o!r five elem5ts v>y greatly 9 _! relative proportions 9 diff]5t lavas4 ,9 all lavas ! sub/ance :i* =ms ! greate/ "p ( ! mass is ! comp\nd ( oxyg5 & silicon1 kn[n z silica or silicic acid4 ,9 its pure =m1 ?is sub/ance is famili> to u z qu>tz1 or rock-cry/al & fl9t4 ,silica is pres5t 9 all lavas 9 proportions :i* v>y f "o-half to f\r-fif?s ( ! :ole mass4 ,n[1 ?is sub/ance1 silica1 has ! prop]ty ( =m+ m complex comp\nds by unit+ ) ! o!r oxides pres5t 9 lavas--namely1 ! oxides ( alum9ium1 magnesium1 calcium1 iron1 potassium1 & sodium4 ,silica is call$ by *emi/s an acid1 ! o!r oxides 9 lavas are t]m$ bases1 & ! comp\nds ( silica ) ! bases are kn[n z silicates4 ,h5ce we see t lavas are compos$ ( a numb] ( diff]5t silicates--! silicates ( alum9ium1 magnesium1 calcium1 iron1 potassium1 & sodium4 ,! above /atem5ts w p]haps be made cle>] by ! accompany+ table f :i* x w be se5 t lavas are comp\nds 9 v>y+ proportions ( six k9ds ( salts--namely1 ! silicates ( alum9a1 magnesia1 lime1 iron1 pota%1 & soda4 ,composition ( ,lavas4 ,elem5ts ,b9>y ,comp\nds ,salts ,acid ,bases ,silicon ,silica-- ,o ,alum9um --,alum9a ,silicate ( ,alum9a x y ,magnesium --,magnesia ,magnesia g e ,calcium --,lime ,lime n ,iron --,iron ,iron ,potassium --,pota% ,pota% ,sodium --,soda ,soda ,n[1 9 "s lavas ! acid con/itu5t1 or silica1 is pres5t 9 mu* l>g] proportions ?an 9 o!rs4 ,^? lavas ) a l>ge proportion ( silica are call$ 'acid lavas1' ^? ) a l[] p]c5tage ( silica1 & !re=e a high] proportion ( ! bases1 are kn[n z ! 'basic lavas4' ,x is conv5i5t to employ ! t]m 'int]m$iate lavas' = ^? 9 :i* ! proportion ( silica is l[] ?an 9 ! acid lavas1 & ! proportion ( ! bases is l[] ?an 9 ! basic lavas4 ,! acid lavas conta9 f #ff to #hj p] c5t1 ( silica2 !y are poor 9 lime1 magnesia1 & oxide ( iron1 b ri* 9 pota% & soda4 ,! basic lavas conta9 f #de to #ee p] c5t1 ( silica2 !y are ri* 9 magnesia1 lime1 & oxide ( iron1 b poor 9 soda & pota%4 ,9 ! int]m$iate lavas ! proportion ( silica v>ies f #ee to #ff p] c5t4 ,z ! basic-lavas conta9 a l>g] proportion ( oxide ( iron & o!r heavy oxides ?an ! acid-lavas1 ! =m] h usually a high] specific gravity ?an ! latt]2 x is1 inde$1 possible 9 mo/ cases to di/+ui% betwe5 ^! diff]5t v>ieties by simply weigh+ !m 9 wat] & 9 air4 ,sid5ote3 ,,diff]5t ,,k9ds ,,( ,,lava4 ,! basic lavas are usually ( mu* d>k] col\r ?an ! add lavas--! t]ms acid lavas1 int]m$iate lavas1 & basic lavas correspond inde$ pretty closely ) ! names tra*ytes1 grey/ones & basalt1 :i* 7 giv5 to ! v>ieties ( lavas by ! old] writ]s on volcanoes1 at a "t :5 _! *emical con/itution _h n be5 accurately /udi$4 ,fre% lavas ( acid composition are usually ne>ly :ite 9 col\r1 int]m$iate lavas are ( v>i\s t9ts ( grey1 & basic lavas ne>ly black4 ,x mu/ be rememb]$1 h[ev]1 t col\r is "o ( ! lea/ p]si/5t1 & !re=e "o ( ! lea/ valuable1 *>act]s by means ( :i* rocks c be discrim9at$1 & also t by exposure to ! influ5ce ( ! atmosph]ic moi/ure ! iron pres5t 9 all lavas is affect$1 & ! lavas belong+ to all classes1 :5 wea!r$1 assume r$di% & r$di%-br[n t9ts4 ,geologi/s h devis$ a great numb] ( names = ! v>i\s k9ds ( lava :i* h be5 f\nd occurr+ r\nd volcanic v5ts 9 diff]5t p>ts ( ! _w1 & ! /udy ( ^! v>ieties is full ( int]e/4 ,= our pres5t purpose1 h[ev]1 x w be suffici5t to /ate t !y ne>ly all fall into five great gr\ps1 kn[n z ! ,rhyolites1 ! ,tra*ytes1 ! ,&esites1 ! ,phonolites1 & ! ,basalts4 ,! ,rhyolites are acid lavas1 ! ,basalts are basic lavas1 & ! ,tra*ytes1 ,&esites1 & ,phonolites1 diff]5t k9ds ( int]m$iate lavas1 di/+ui%$ by ! p>ticul> m9]als :i* !y conta94 ,be=e we "p f ?is subject ( ! classification ( lavas accord+ to _! *emical composition1 x w be well to po9t out t !re exi/s a small gr\p ( lavas :i* /& q by !mselves1 & _c be ref]r$ to ei!r ( ! classes we h indicat$4 ,!y conta9 a small] proportion ( silica1 & a mu* l>g] proportion ( magnesia & oxide ( iron ?an ! o!r lavas1 & may be made to con/itute a small sub-gr\p1 to :i* we may apply ! t]m ( 'ultra-basic lavas4' ,al?\gh mu* less widely di/ribut$ ?an ! o!r v>ieties1 !y are1 9 "s respects1 z we %all pres5tly h to po9t out1 ( f> great] int]e/ to ! geologi/ ?an all ! o!r k9ds ( lavas4 ,sid5ote3 ,,m9ute ,,/ructure ,,( ,,lavas4 ,we w n[ proce$ to consid] ! facts :i* are br\ght to light conc]n+ ! nature ( lavas1 :5 !y are /udi$ by ! aid ( ! microscope4 ,al?\gh mo/ lavas appe> at fir/ sight to be opaque sub/ances1 yet x is easy to prep>e slices ( !m :i* are suffici5tly ?9 to transmit light4 ,9 su* ?9 transp>5t slices we are able to make out1 by ! aid ( ! microscope1 c]ta9 v int]e/+ details ( /ructure1 :i* af=d new & important evid5ce be>+ on ! mode ( orig9 ( ^! rocks4 ,ho/ lavas are capable ( be+ melt$ by ! heat ( our furnaces2 b ! diff]5t k9ds ( lava v>y greatly 9 ! degree ( _! fusibility4 ,! basic lavas1 or ^? ) ! smalle/ proportion ( silica1 are usually mu* m easily fusible ?an ^? :i* conta9 a high p]c5tage ( silica1 ! add lavas4 ,n[1 x is a v notewor?y circum/ance1 t :5 a lava is artificially fus$ x assumes on cool+ v diff]5t physical *>act]s to ^? :i* 7 pres5t$ by ! orig9al rock4 ,if we exam9e ! fre%ly-brok5 surface ( a piece ( lava1 we %all1 9 mo/ cases1 f9d t x conta9s a great numb] ( ^? regul>-%ap$ bodies :i* we call cry/als2 9 "s cases ^! cry/als are s small z to be sc>cely visible to ! nak$ eye1 9 o!rs !y may be an in* or m 9 l5g?4 ,mo/ lavas are ?us se5 to be l>gely made up ( cry/als ( diff]5t m9]als4 ,! m9]als :i* are usually conta9$ 9 lavas are qu>tz1 ! v>i\s k9ds ( felsp>1 augite1 hornbl5de1 ! diff]5t k9ds ( mica1 oliv9e1 & magnetite4 ,b :5 a piece ( lava is melt$ 9 a furnace1 all ^! cry/all9e m9]als disappe>1 & ! result+ product is ! homog5e\s sub/ance :i* we call glass4 ,if1 z _m suppose1 lavas acquire ! fluidity :i* !y possess :5 issu+ f volcanic v5ts z ! result ( simple fusion x is /range t artificially fus$ lavas d n agree m closely 9 "* ) ! natural products4 ,a c>eful exam9ation ( diff]5t k9ds ( lavas1 h[ev]1 w %[ t !y v>y v greatly 9 "* among !mselves4 ,"s lavas are z p]fectly glassy 9 /ructure z ^? :i* h be5 artificially fus$1 :ile o!rs conta9 great numb]s ( cry/als1 :i* may sometimes be ( v l>ge size4 ,if we prep>e ?9 transp>5t slices ( ^! diff]5t k9ds ( lavas1 & exam9e !m by ! aid ( ! microscope1 we %all f9d t lavas are made up ( two k9ds ( mat]ials1 a base or gr\ndmass ( a glassy "*1 & di/9ct cry/als ( diff]5t m9]als1 :i* are irregul>ly di/ribut$ ?r\gh ?is glassy base1 l ! rais9s1 currants1 & pieces ( c&i$ peel 9 a cake4 ,9 "s cases ! glassy base makes up ! :ole mass ( ! rock2 9 o!rs1 small] or l>g] numb]s ( cry/als are se5 to be scatt]$ ?r\gh a glassy base2 :ile 9 o!rs aga9 ! cry/als are s num]\s t ! pres5ce ( an int]v5+ glassy base or gr\ndmass c only be detect$ by ! aid ( ! microscope4 ,sid5ote3 ,,/udy ,,( ,,lavas ,,) ,,! ,,microscope4 ,if ?9 slices ( ! glassy mat]ials ( lavas be exam9$ ) high magnify+ p[]s1 new & int]e/+ facts are reveal$4 ,?r\gh ! mid/ ( ! cle> glassy sub/ance cl\dy pat*es are se5 to be diffus$2 &1 if we exam9e !m ) a /ill high] p[]1 ^! cl\dy pat*es resolve !mselves into innum]able p>ticles1 "s transp>5t & o!rs opaque1 hav+ v def9ite outl9es4 ,at ! same "t fre% cl\dy pat*es are br\ght into view1 :i* c only be resolv$ by yet high] p[]s ( ! microscope4 ,9 exam9+ ^! natural glasses by ! aid ( ! microscope1 we are =cibly rem9d$ ( :at occurs :5 ! ',milky ,way' & "s o!r p>ts ( ! heav5s are /udi$ ) a telescope4 ,z ! p[] ( ! in/rum5t is increas$ ! nebul\s pat*es are resolv$ into di/9ct />s1 b fre% nebul\s masses come into view1 :i* are 9 turn resolv$ into />s1 :5 high] p[]s ( ! in/rum5t are employ$4 ,9 ! ,frontispiece1 ,no4 #a illu/rates ! appe>ance pres5t$ by ^! volcanic glasses :5 exam9$ ) a high p[] ( a microscope4 ,?r\gh a glassy base is se5 a numb] ( diffus$ nebul\s pat*es1 :i* are 9 places resolv$ into def9ite p>ticles4 ,^! m9ute p>ticles ( def9ite =m1 :i* ! microscope has reveal$ 9 ! mid/ ( ! glassy portions ( lava1 h receiv$ ! "n ( microli?s1 or cry/allites4 ,! /udy ( ! *>act]s & mode ( arrangem5t ( ^! microli?s or cry/allites has 9 rec5t ye>s ?r[n mu* new light on ! int]e/+ problems pres5t$ by lavas4 ,9 "s glassy lavas ! microli?s or cry/allites1 in/ead ( be+ indiscrim9ately diffus$ ?r\gh ! mass ( ! base or gr\ndmass1 are f\nd to be collect$ toge!r into gr\ps ( v def9ite =m4 ,9 ,no4 #b ( ! ,frontispiece we h a section ( a glassy rock 9 :i* ! cry/allites h unit$ toge!r1 s z to build up gr\ps pres5t+ ! mo/ /rik+ resemblance to fronds ( f]ns4 ,ar\nd ^! gr\ps spaces ( de> glass h be5 left by ! ga!r+ up ( ! cry/allites1 :i* 9 o!r p>ts ( ! mass are se5 to be equally diffus$ ?r\gh x4 ,9 ?is =mation ( gr\ps ( microli?s we _c b recognise ! action ( ^? cry/all9e =ces1 :i* on fro/y morn+s cov] our w9d[s ) a mimic vegetation compos$ ( icy p>ticles4 ,9 o!r cases1 aga91 ! cry/allites scatt]$ ?r\gh ! glassy portions ( lavas unite 9 radial gr\ps ab\t c]ta9 c5tres1 & ?us build up globul> masses to :i* ! "n ( 'sphrulites' has be5 giv54 ,no4 #c 9 ! ,frontispiece illu/rates ! =mation ( ^! sphrulites4 ,n[1 a c>eful /udy ( ! microli?s or cry/allites has prov$ t !y are ! m9ute elem5ts ( :i* ^? wond]fully beautiful objects :i* we call cry/als are built up4 ,9 "s cases we c see t ! cry/allites are becom+ unit$ toge!r 9 positions det]m9$ by ma!matical laws1 & ! gr\p is gradually assum+ ! outw>d =m & int]nal /ructure ( a cry/al4 ,9 o!r cases cry/als may be f\nd :i* are und]go+ a dis9tegrat+ action1 & are !n se5 to be made up ( m9ute elem5ts simil> to ! cry/allites or microli?s ( glassy rocks4 ,sid5ote3 ,,cry/allites ,,& ,,cry/als4 ,! conclusion is confirm$ by ! fact t if we take an artificially fus$ lava & all[ x to cool sl[ly1 x w be f\nd t ! glassy mass into :i* x has resolv$ itself conta9s num]\s cry/allites4 ,if ! cool+ process be /ill fur!r prolong$1 ^! cry/allites w be f\nd to h unit$ !mselves into def9ite gr\ps1 & sometimes di/9ct cry/als are =m$ 9 ! mass2 "u ^! circum/ances ! rock frequ5tly loses its glassy appe>ance & assumes a /ony "*4 ,9 connection ) ?is subject1 x may be m5tion$ t "s ye>s ago a v +5i\s inv5tion 0 submitt$ to trial 9 ! ,works ( ! ,messrs4 ,*ance1 ( ,birm+ham4 ,x _h be5 sugge/$ t if c]ta9 lavas ( easy fusibility 7 melt$ & p\r$ into m\lds1 we might ?us obta9 elaborately ornam5t$ /one-"w1 compos$ ( ! h>de/ mat]ial1 )\t ! lab\r ( ! mason4 ,! molt5 rock :5 quickly cool$ 0 f\nd to assume ! =m ( a black glass1 b :5 v sl[ly cool$ pass$ into a /ony mat]ial4 ,un=tunately1 x 0 f\nd t ?is mat]ial did n )/& ! wea!r l ord9>y build+ /ones1 &1 9 consequ5ce1 ! manufacture _h to be ab&on$4 ,n[1 ! /udy ( ! products ( volcanoes has l$ geologi/s to recognise ! true relations betwe5 glassy & cry/all9e rocks4 ,9 ! amorph\s mixture ( v>i\s silicates :i* compose a glass1 *emical aff9ity causes ! sep>ation ( c]ta9 portions ( def9ite composition1 & ^! =m ! microli?s or elem5ts ( :i* diff]5t cry/all9e m9]als are built up4 ,"u ! influ5ce ( ! cry/all9e =ces1 !re is a great %ak+ or agitation 9 ! mass1 & ! microli?s ( simil> k9d come toge!r & become unit$1 l ! fragm5ts 9 ,ezekiel's valley ( dry bones4 ,al?\gh we _c see ?is process tak+ place "u our eyes1 9 a mass ( lava1 yet we may /udy specim5s 9 :i* ! action has be5 arre/$ 9 its diff]5t /ages4 ,9 ord] to und]/& ! developm5t ( an acorn into an oak-tree1 x is n necess>y to wat* ! :ole s]ies ( *anges 9 a p>ticul> case4 ,a visit to an oak-?icket1 9 :i* illu/rations ( e /age ( ! trans=mation may be f\nd1 w af=d u equally c]ta9 in=mation on ! subject4 ,9 ! same way by ! exam9ation ( su* a s]ies ( rock-sections z t repres5t$ 9 ! ,frontispiece1 we may und]/& h[1 9 ! mid/ ( a mass ( mix$ silicates con/itut+ a natural glass1 ! sep>ation ( microli?s takes place2 ^! unite into gr\ps :i* are ! skeletons ( cry/als1 & f9ally1 by ! fill+ up ( ! empty spaces 9 ^! skeletons1 complete cry/als are built up4 ,! s]ies ( op]ations may1 h[ev]1 be int]rupt$ at any /age1 & ?is /age we may h ! *ance ( /udy+4 ,sid5ote3 ,,glassy ,,& ,,cry/all9e ,,lavas4 ,we are able1 z we %all %[ 9 a future *apt]1 to exam9e _m rock-masses t h evid5tly =m$ ! res]voirs f :i* volcanoes h be5 suppli$1 & o!rs t fill up ! ducts :i* con/itut$ ! means ( communication betwe5 ^! subt]ranean res]voirs1 & ! surface ( ! e>?4 ,n[ 9 ^! subt]ranean regions ! lavas h be5 plac$ "u conditions especially fav\rable = ! action ( ! cry/all9e =ces--!y mu/ h cool$ ) extreme sl[ness1 & !y mu/ h be5 "u an enorm\s pressure1 produc$ 9 "p by ! weight ( ! sup]9cumb5t rocks1 & 9 "p by ! expansive =ce ( ! imprison$ /eam4 ,we are n1 !re=e1 surpris$ to f9d t 9 ^! subt]ranean regions1 ! lavas1 :ile reta9+ ! same *emical composition1 h assum$ a mu* m p]fectly cry/all9e condition4 ,9 "s cases1 inde$1 ! :ole rock has become a mass ( cry/als )\t any base or gr\ndmass at all4 ,an exam9ation ( ! ,frontispiece w illu/rate ?is p]fect gradation f ! glassy to ! cry/all9e condition ( lavas4 ,no4 #a repres5ts a glass ?r\gh :i* microli?s or cry/allites ( diff]5t dim5sions & "* are diffus$4 ,9 ,nos4 #b & #c1 ^! cry/allites h unit$ to =m regul> gr\ps4 ,9 ,no4 #d1 :i* may be tak5 z typical ( ! features pres5t$ by mo/ lavas1 we h a glassy gr\ndmass conta9+ microli?s 7a 'crypto-cry/all9e base'71 ?r\gh :i* di/9ct cry/als are di/ribut$4 ,nos4 #e & #f illu/rate ! *>act]s pres5t$ by lavas :i* h consolidat$ at consid]able dep?s b5ea? ! surface2 9 ! =m] we h a mans ( small cry/als 7a 'micro-cry/all9e base'7 ) l>g] cry/als scatt]$ ?r\gh x2 :ile ! latt] is entirely made up ( l>ge cry/als )\t any trace ( a base or gr\ndmass4 ,n[1 z all lavas are f\nd sometimes assum+ ! glassy condition at ! surface1 s :5 se5 9 ! masses :i* h consolidat$ ) extreme sl[ness1 & "u great pressure1 9 subt]ranean regions1 ! same mat]ials are f\nd 9 ! condition ( a rock :i* is built up entirely ( cry/als4 ,*emi/s h f\nd t artificial mixtures ( silicates 9 :i* soda & pota% are pres5t 9 consid]able quantities1 h a great t5d5cy to assume ! glassy condition on cool+ f a /ate ( fusion1 & glass manufactur]s are always c>eful to use consid]able proportions ( ! alkalis z +r$i5ts1 9 mak+ glass4 ,x is f\nd1 9 l mann]1 t ^? lavas :i* conta9 ! l>ge/ portion ( ! silicates ( soda & pota% 7! 'acid lavas'7 mo/ frequ5tly assume ! condition ( a natural glass4 ,geologi/s h giv5 di/9ct names to ! glassy & ! p]fectly cry/all9e conditions ( ! diff]5t k9ds ( lavas1 ! glassy v>ieties be+ f\nd 9 masses :i* h cool$ rapidly ne> ! surface1 & ! cry/all9e v>ieties 9 masses :i* h cool$ sl[ly at great dep?s4 ,! names ( ^! two conditions ( ! five great classes into :i* we h divid$ lavas are z foll[s3-- ,sid5ote3 ,,highly ,,cry/all9e ,,igne\s ,,rocks4 ,cry/all9e ,=ms4 ,lavas4 ,glassy ,=ms4 ,granite ,rhyolite ,sy5ite ,tra*yte ,obsidian4 ,diorite ,&esite ,miascite ,phonolite ,gabbro ,basalt ,ta*ylyte4 ,z vitre\s rocks h little 9 _! g5]al appe>ance to di/+ui% !m f "o ano!r1 ! glassy =ms ( ! fir/ f\r classes ( lava h n hi!rto receiv$ di/9ct names1 b h be5 conf\nd$ toge!r "u ! "n ( obsidian4 ,if we det]m9e ! specific gravities ( rocks hav+ ! same composition b diff]5t /ructures1 we %all f9d t !y become heavi] 9 proportion z ! cry/all9e /ructure is develop$ 9 !m4 ,?us gabbro is heavi]1 b ta*ylyte is light] ?an basalt1 bulk = bulk1 ?\gh all h ! same *emical composition4 ,nor are ! cry/als conta9$ 9 lavas less wor?y ( c>eful /udy1 by ! aid ( ! microscope1 ?an ! m or less glassy gr\ndmass 9 :i* !y are emb$d$4 ,mr4 ,sorby has %[n t ! cry/als f\nd 9 lavas1 exhibit _m int]e/+ po9ts ( diff]5ce f ^? :i* sep>ate out 9 ! mid/ ( a mass ( ! same rock1 :5 x has be5 artificially melt$ & sl[ly cool$4 ,!re are o!r facts :i* also po9t to ! conclusion t1 :ile ! glassy gr\ndmass ( lavas may h be5 =m$ by cool+ f a /ate ( fusion1 ! l>g] & well-=m$ cry/als 9 ^! lavas mu/ h be5 =m$ "u o!r & v diff]5t conditions4 ,! l>g] cry/als 9 lavas exhibit evid5ce ( hav+ be5 sl[ly built up 9 ! mid/ ( a glassy mass1 conta9+ cry/allites & small cry/als4 ,we c frequ5tly detect evid5ce ( ! int]ruptions :i* h occurr$ 9 ! gr[? ( ^! cry/als 9 ! conc5tric zones ( diff]5t col\r or texture :i* !y exhibit2 & portions ( ! glassy base or gr\ndmass are (t5 f\nd to h be5 caught up & enclos$ 9 ^! cry/als dur+ _! gr[?4 ,b :5 we f9d1 z 9 ! porphyritic pit*/ones1 a glassy base conta9+ only m9ute cry/allites1 ?r\gh :i* l>ge & p]fectly =m$ cry/als are di/ribut$1 we c sc>cely d\bt t ! m9ute cry/allites & ! l>g] cry/als h sep>at$ f ! base "u v diff]5t conditions4 ,?is is indicat$ by ! bet t we detect 9 ^! cases no connect+ l9ks betwe5 ! embryo microli?s & ! p]fect cry/als2 & a confirmation ( ! conclusion is se5 9 ! circum/ance t _m ( ! cry/als are f\nd to h suff]$ injury z if f transport1 _! edges & angles be+ r\nd$ & abrad$1 & portions be+ occasionally brok5 (f f !m4 ,h5ce we are l$ to conclude t ! l>g] cry/als 9 lavas 7 probably sep>at$ f ! amorph\s mass 9 ! subt]ranean res]voirs b5ea? ! volcano1 & 7 c>ri$ up to ! surface 9 ! mid/ ( ! liquefi$ glassy mat]ial :i* =ms ! gr\ndmass ( lavas4 ,:5 we come to exam9e ^! cry/als m closely1 we f9d t c]ta9 v curi\s ph5om5a are exhibit$ by !m :i* l5d p[]ful support to ?is conclusion4 ,illu/ration3 ,fig4 #g4--,m9ute ,cavities1 conta9+ ,liquids1 9 ! ,cry/als ( ,rocks4 ,sid5ote3 ,,liquid ,,cavities ,,9 ,,cry/als4 ,x is f\nd conv5i5t by geologi/s to designate ^? rocks :i* h consolidat$ 9 deep-seat$ portions ( ! e>?'s cru/ z ,platonic ,rocks1 conf9+ ! "n ( ,volcanic rocks to ^? consolidat+ ,at ! surface2 b ,plutonic & ,volcanic ,rocks %ade into "o ano!r by ! mo/ ins5sible gradations4 ,:5 ! cry/als emb$d$ 9 granitic rocks1 & 9 "s lavas1 are exam9$ ) ! high] p[]s ( ! microscope1 !y are frequ5tly se5 to conta9 great numb]s ( excessively m9ute cavities4 ,ea* ( ^! cavities resembles a small _s-level1 hav+ a quantity ( liquid & a bubble ( gas )9 x4 ,9 fig4 #g we h giv5 a s]ies ( draw+s ( ^! cavities 9 cry/als z se5 "u a high p[] ( ! microscope4 ,9 ,no4 #a a gr\p ( su* cavities is repres5t$1 "o ( :i* is full ( liquid1 :ile two o!rs are q empty2 ! rema9+ cavities all conta9 a liquid ) a mov+ bubble ( gas4 ,9 ,no4 #b two l>g] cavities are %[n1 conta9+ a liquid & a bubble ( gas2 & x w be se5 f ^! h[ v>i$ 9 =m ^! cavities sometimes are4 ,9 ,nos4 #c1 #d & #f ! liquid 9 ! cavities conta9s1 besides ! bubbles1 sev]al1 m9ute cry/als2 & 9 ,no4 #f we h a cavity conta9+ two liquids & a bubble4 ,9 ! l>ge/ ( su* cavities ! bubble is se5 to *ange its place s z always to lie at ! upp] side ( ! cavity1 :5 ! position ( ! latt] is alt]$1 j z 9 a _s-level4 ,b 9 ! smalle/ cavities ! bubbles appe> to be end[$ ) a p[] ( spontane\s movem5t2 l imprison$ creatures try+ to escape1 ^! bubbles are se5 cont9ually oscillat+ f side to side & f end to end ( ! cavities :i* enclose !m4 ,9 fig4 #h a m9ute cavity conta9+ a liquid & bubble is %[n1 ! pa? pursu$ by ! latt] 9 its wond]ful gyrations be+ indicat$ by ! d>k l9e4 ,^! cavities are exce$+ly m9ute1 & s num]\s t 9 "s cry/als !re mu/ be millions ( !m pres5t2 inde$1 9 c]ta9 cases1 z we increase ! magnify+ p[] ( our microscopes1 new & small] cavities cont9ually become visible4 ,x has be5 e/imat$ t 9 "s in/ances ! numb] ( ^! m9ute liquid-cavities 9 ! cry/als ( rocks am\nts to f "o ?\s& millions to t5 ?\s& millions 9 a cubic in* ( space4 ,illu/ration3 ,fig4 #h--,m9ute ,liquid-cavity 9 a ,cry/al1 ) a mov+ ,bubble4 7,! pa? ( ! bubble is indicat$ by ! d>k l9e47 ,sid5ote3 ,,nature ,,( ,,liquids ,,9 ,,cavities4 ,:at is ! nature ( ! liquids :i* are ?us imprison$ 9 ^! cavities conta9$ 9 ! cry/als ( lavas & granites8 ,c>eful exp]im5ts h giv5 a conclusive answ] to ?is "q4 ,9 _m cases ! liquid is wat]1 usually conta9+ consid]able quantities ( sal9e matt] dissolv$ 9 x4 ,sometimes ! sal9e matt]s are pres5t 9 su* abundance t !y _c all pass into solution1 b cry/allise out1 z 9 fig4 #g--,nos4 #c1 #d1 #e--:]e cubic cry/als ( ! *lorides ( sodium & potassium are se5 float+ 9 ! liquid2 9 o!r cases ! liquid is a hydroc>bon l ! m9]al oil :i* is pres5t 9 great abundance 9 deep-seat$ rocks 9 _m p>ts ( ! globe4 ,b 9 "s o!r cases ! liquid conta9$ 9 ! cavities ( cry/als is f\nd to be "o :i* c\ld sc>cely be anticipat$ to occur "u su* circum/ances--! gas kn[n z c>bonic add1 :i* "u extreme pressure c be r$uc$ to a liquid condition4 ,9 cavities conta9+ liquefi$ c>bonic acid1 if ! rock be w>m$ up to #hf or #ij ,fahr5heit ! bubble sudd5ly vani%es1 sometimes ) an appe>ance l ebullition or boil+1 z repres5t$ 9 fig4 #i4 ,n[ ! temp]ature :i* we h indicat$ is ! 'critical po9t' ( c>bonic acid1 & above t temp]ature x _c exi/ 9 a liquid condition1 h[ev] great may be ! pressure to :i* x is subject$4 ,! liquid has be5 conv]t$ into a gas :i* completely fills ! cavity4 ,! c>bonic acid 9 ! cavities ( cry/als has frequ5tly be5 isolat$ & its nature plac$ beyond d\bt by spectroscopic & ord9>y *emical te/s4 ,! pres5ce ( ^! liquids 9 ! cavities ( cry/als cle>ly proves t ! latt] mu/ h be5 =m$ "u enorm\s pressure--a pressure suffici5tly great to r$uce1 n only /eam1 b also volatile hydroc>bons & ev5 gase\s c>bonic acid1 to ! bulk ( a liquid4 ,illu/ration3 ,fig4 #i4--;,cavity 9 ,cry/al conta9+ ,c>bonic-,acid ,gas at a temp]ature ( #hf ,f41 & pass+ f ! liquid to ! gase\s condition4 ,su* conditions ( enorm\s pressure we may inf] to exi/ 9 ! deep-seat$ res]voirs b5ea? volcanoes1 :]e1 besides ! weight ( ! sup]9cumb5t rock-masses1 we h ! compress+ =ce ( great quantities ( ela/ic vap\r held 9 conf9em5t4 ,! cry/als ( :i* granitic rocks are entirely built up exhibit cle> evid5ce ( hav+ be5 all =m$ "u ^! conditions ( enorm\s pressure4 ,! glassy base or gr\ndmass ( lavas1 on ! o!r h&1 pres5ts all ! *>act]s ( mat]ials t h cool$ f a /ate ( fusion4 ,mo/ lavas consi/ 9 "p ( cry/als1 exhibit+ fluid-cavities l ^? pres5t 9 granite1 & 9 "p ( a base1 :i* has evid5tly be5 =m$ by ! cool+ ( a fus$ mass4 ,we are !re=e ju/ifi$ 9 conclud+ t ! cry/als h be5 =m$ 9 subt]ranean recesses1 & t ! gr\ndmass or base has consolidat$ at ! surface4 ,! be>+ ( ^! conclusions ^u "s ( ! great problems pres5t$ by volcanoes we %all h occasion to po9t out 9 ! sequel4 ,sid5ote3 ,,cause ,,( ,,movem5t ,,( ,,bubbles4 ,"o ( ! mo/ int]e/+ inquiries sugge/$ by ! /udy ( ! liquid-cavities 9 volcanic rocks is t ( ! cause ( ! app>5tly spontane\s movem5t ( ! bubbles :i* we h describ$ z tak+ place 9 "s ( ! small] ( !m4 ,! +5i\s exp]im5ts ( ,mr4 ,noel ,h>tley h sugge/$ to ,pr(essor ,/okes an explanation :i* is probably ! true "o4 ,x appe>s t ^! m9ute globes ( vap\r are 9 su* a /ate ( un/able equilibrium z to be affect$ by ! smalle/ *anges ( temp]ature1 & t ! v>iations 9 ! heat ( ! atmosph]e1 due to curr5ts ( air & ! movem5t ( w>m or cold bodies ?r\gh x1 are suffici5t to cause ! oscillation ( ^! s5sitively pois$ bubbles4 ,! %ort acc\nt :i* we h be5 able to give 9 ! =ego+ pages ( ! rese>*es t h be5 c>ri$ on conc]n+ ! nature ( ! mat]ials eject$ f volcanoes w s]ve to %[ t ^! inve/igations h already made kn[n _m facts ( great int]e/1 & t ! f>!r pursuit ( !m is full ( ! highe/ promise4 ,to ! sci5tific work] no subject is too va/ = 8 rese>*1 no object s m9ute z to be unwor?y ( 8 mo/ pati5t /udy4 ,9 "s ( our future inquiries conc]n+ ! nature ( volcanic action1 we %all be l$ to an inve/igation ( ! ph5om5a display$ 9 ! sun1 moon1 comets & o!r great bodies ( ! univ]se2 b ano!r road to tru?s ( ! same gr&eur & importance is f\nd1 z we h se51 9 an exam9ation ( ! mode ( developm5t ( cry/allites1 & a /udy ( ! mat]ials conta9$ 9 ! microscopic cavities ( ! m9ute/ cry/als4 ,,*apt] ,,iv4 ,,! ,,di/ribution ,,( ,,! ,,mat]ials ,,eject$ ,,f ,,volcanic ,,v5ts4 ,! escape ( great quantities ( /eam & o!r gases f ! mid/ ( a mass ( fluid or semi-fluid lava gives rise to ! =mation ( va/ quantities ( fro? or foam ^u its surface4 ,?is fro? or foam1 :i* is =m$ ^u ! surface ( lava by ! escape ( gase\s matt]s f )9 x1 is made up ( portions ( ! lava di/5d$ into vesicles1 9 ! same way t bubbles are =m$ on ! surface ( wat]4 ,x be>s precisely ! same relation to ! liquid mass ( lava t ! :ite cre/ ( foam ^u an advanc+ wave does to ! sea-wat]1 f ! bubbles ( :i* x is =m$4 ,?is fro? ^u ! surface ( lavas v>ies greatly 9 "* accord+ to ! nature ( ! mat]ial f :i* x is =m$4 ,9 ! majority ( cases ! lavas consi/1 z we h se51 ( a mass ( cry/als float+ 9 a liquid magma1 & ! di/5sion ( su* a mass by ! escape ( /eam f its mid/ gives rise to ! =mation ( ! r\gh c9d]y-look+ mat]ial to :i* ! "n ( 'scoria' is appli$4 ,b :5 ! lava conta9s no ready-=m$ cry/als1 b consi/s entirely ( a glassy sub/ance 9 a m or less p]fect /ate ( fusion1 ! lib]ation ( /eam gives rise to ! =mation ( ! beautiful mat]ial kn[n z 'pumice4' ,pumice consi/s ( a mass ( m9ute glass bubbles2 ^! bubbles h n usually1 h[ev]1 reta9$ _! globul> =m1 b h be5 elongat$ 9 "o direction ?r\gh ! movem5t ( ! mass :ile x 0 /ill 9 a pla/ic /ate4 ,! /eam frequ5tly escapes f lava ) su* viol5ce t ! fro? or scum on its surface is brok5 up & scatt]$ 9 all directions1 z ! foam cre/s ( waves are disp]s$ by ! w9d dur+ a /orm4 ,9 ?is way fragm5ts ( scoria or pumice are (t5 ?r[n to ! height ( _m hundr$s or ?\s&s ( feet into ! atmosph]e1 z we h se5 is ! case at ,/romboli & ,vesuvius4 ,inde$1 dur+ viol5t eruptions1 a cont9u\s upw>d dis*>ge ( ^! fragm5ts is ma9ta9$1 ! ragg$ c9d]y masses hurtl+ "o ano!r 9 ! atmosph]e1 z !y are %ot p]p5dicul>ly upw>ds to an enorm\s height & fall back into ! v5t2 or !y may rise obliquely & describe curves s z to desc5d outside ! orifice f :i* !y 7 eject$4 ,sid5ote3 ,,f95ess ,,( ,,volcanic ,,du/4 ,dur+ _! upw>d dis*>ge & d[nw>d fall1 ! c9d]y fragm5ts are by attrition cont9ually r$uc$ to small] dim5sions4 ,! noise made by ^! fragm5ts1 z !y /rike aga9/ "o ano!r 9 ! air dur+ _! rise & fall1 is "o ( ! mo/ notewor?y accompanim5ts ( volcanic eruptions4 ,x has be5 notic$ t 9 _m cases !re is a con/ant dim9ution 9 ! size ( ! fragm5ts eject$ dur+ a volcanic outbur/1 ?is be+ d\btless due to ! friction ( ! masses z !y are eject$ & re-eject$ f ! v5t4 ,?us x is relat$ by ,mr4 ,p\lett ,scrope1 :o wat*$ ! ,vesuvian eruption ( #ahbb1 :i* la/$ = ne>ly a mon?1 t dur+ ! e>li] /ages ( ! outbur/ fragm5ts ( enorm\s size 7 ?r[n out ( ! crat]1 b by con/ant re-ejection ^! 7 gradually r$uc$ 9 size1 till at la/ only ! mo/ impalpable du/ issu$ f ! v5t4 ,?is du/ fill$ ! atmosph]e1 produc+ 9 ! city ( ,naples 'a d>kness t might be felt1' & s excessively f9ely divid$ 0 x1 t x p5etrat$ into all draw]s1 boxes1 & ! mo/ closely fa/5$ receptacles1 fill+ !m completely4 ,mr4 ,:ymp] relates t1 :ile /&+ on ! summit ( ,*imborazo1 he witness$ an eruption ( ,cotopaxi1 :i* is di/ant m ?an fifty miles f ! =m] m\nta94 ,! f9e volcanic du/ fell 9 great quantities ar\nd him1 & he e/imat$ t no less ?an two millions ( tons mu/ h be5 eject$ dur+ ?is slight outbur/4 ,pr(essor ,bonney has exam9$ ?is volcanic du/ f ,cotopaxi1 & calculates t x w\ld take f #d1jjj to #be1jjj p>ticles to make up a gra9 9 weight4 ,v>i\s names h be5 giv5 by geologi/s to ! fragm5ts eject$ f volcanic v5ts1 :i*1 z we h se51 diff] greatly 9 _! dim5sions & o!r *>act]s4 ,sometimes masses ( m or less fluid lava are flung bodily to a great height 9 ! atmosph]e4 ,dur+ _! rise & fall ^! masses are caus$ to rotate1 & 9 consequ5ce assume a globul> or sph]oidal =m4 ,! wat] imprison$ 9 ^! masses1 dur+ _! passage ?r\gh ! atmosph]e1 t5ds to exp& into /eam1 & !y become m or less completely di/5d$ ) bubbles4 ,su* masses1 :i* sometimes assume v regul> & /rik+ =ms1 are kn[n z 'volcanic bombs4' ,_m volcanic bombs h a solid nucleus ( refractory mat]ials4 ,! l>ge1 r\gh1 angul>1 c9d]y-look+ fragm5ts are t]m$ 'scori4' ,:5 r$uc$ to ! dim5sions ( a m>ble or pea !y are usually call$ by ! ,italian "n ( 'lapilli4' ,! /ill f9] mat]ials are kn[n z volcanic s& & du/4 ,!re are1 h[ev]1 two names :i* are frequ5tly appli$ to ^! fragm5t>y mat]ials eject$ f volcanoes1 :i* are p]haps liable to give rise to misconception4 ,^! are ! t]ms 'c9d]s' & 'a%es4' ,x mu/ be rememb]$ t ! scori or c9d]y-look+ masses are n1 l ! c9d]s ( our fires1 ! product ( ! p>tial combu/ion ( a mat]ial conta9+ inflammable gases1 b are1 l ! cl9k]s ( furnaces & brick-kilns1 portions ( p>tially vitrifi$ & fus$ rock di/5d$ by gases4 ,s1 too1 volcanic a%es only resemble ! a%es ( our grates 9 be+ v f9ely divid$2 !y are n1 l ! latt]1 ! incombu/ible residue ( a mass :i* has be5 burnt4 ,sid5ote3 ,,volcanic ,,bombs ,,& ,,pele',s ,,hair4 ,! glassy lavas1 :5 di/5d$ by escap+ gases1 give rise to ! =mation ( pumice1 ! :ite col\r ( :i*1 z 9 ! case ( ! foam ( a wave1 is due to ! reflection ( a portion ( ! light 9 its frequ5t passage f "o m$ium to ano!r--9 ?is case f air to glass1 & f glass to air4 ,! volcanic bombs =m$ f glassy lavas are (t5 ( especially beautiful & regul> =ms4 ,sometimes ! passage ( /eam ?r\gh a mass ( molt5 glass produces l>ge quantities ( a mat]ial resembl+ spun glass4 ,small p>ticles or %ots ( ! glass are c>ri$ into ! air & leave beh9d !m ?91 glassy filam5ts l a tail4 ,at ! volcano ( ,kilauea 9 ,hawaii ?is filam5t\s volcanic glass is abundantly produc$1 & is kn[n z ',pele's ,hair'--,pele be+ ! "n ( ! goddess ( ! m\nta94 ,birds' ne/s are sometimes f\nd compos$ ( ?is beautiful mat]ial4 ,9 rec5t ye>s an artificial sub/ance simil> to ?is ,pele's hair has be5 ext5sively manufactur$ by pass+ jets ( /eam ?r\gh ! molt5 slag ( iron-furnaces2 x resembles cotton-wool1 b is made up ( f9e ?reads ( glass1 & is employ$ = ! pack+ ( boil]s & o!r purposes4 ,! v f9ely-divid$ volcanic du/ is (t5 borne to enorm\s di/ances f ! volcano out ( :i* x has be5 eject$4 ,! =ce ( ! /eam-curr5t c>ry+ ! fragm5ts into ! atmosph]e is (t5 s great t !y rise to ! height ( sev]al miles above ! m\nta94 ,"h !y may actually pass into ! upp] curr5ts ( ! atmosph]e & be borne away to ! di/ance ( _m hundr$s or ?\s&s ( miles4 ,h5ce x is n an unusual circum/ance = vessels at sea to enc\nt] at great di/ances f l& fall+ %[]s ( ?is f9ely divid$1 volcanic du/4 ,we sometimes meet ) ?is f>-travell$1 volcanic du/ "u v unexpect$ circum/ances4 ,?us1 9 ! spr+ ( #ahge ,i _h occasion to visit ,pr(4 ,vom ,ra? ( ,bonn1 :o %[$ me a quantity ( f9e volcanic du/ :i* _h dur+ ! pa/ w9t] fall5 9 consid]able quantities 9 c]ta9 p>ts ( ,norway4 ,?is du/1 ^u microscopic exam9ation1 prov$ to be s simil> to :at 0 kn[n to be frequ5tly eject$ f ! ,icel&ic volcanoes t a /rong presumption 0 rais$ t volcanic outbur/s _h be5 go+ on 9 t isl&4 ,on return+ to ,engl& ,i f\nd t ! fir/ /eam] ( ! season _h j rea*$ ,lei? f ,icel&1 br++ ! intellig5ce t v viol5t eruptions _h tak5 place dur+ ! prec$+ mon?s4 ,sid5ote3 ,,disp]sion ,,( ,,pumice ,,& ,,volcanic ,,du/4 ,?is f9ely-divid$ volcanic du/ is ?us c>ri$ by ! w9ds & spread ov] e "p ( ! ocean4 ,ev]yone is famili> ) ! fact t pumice floats ^u wat]2 ?is x does1 n because x is a mat]ial specifically light] ?an wat]1 b because cavities fill$ ) air make up a great "p ( its bulk4 ,if we pulv]ise pumice1 we f9d ! p[d] s9ks readily 9 wat]1 b ! rock 9 its natural condition floats = ! same reason t an iron %ip does--because ( ! air-*amb]s :i* x encloses4 ,:5 ?is pumice is eject$ f a volcano & falls into a riv] or ! ocean1 x floats = a long "t1 till decomposition causes ! break+ d[n ( ! ?9 glassy p>titions betwe5 ! air *amb]s1 & causes ! admission ( wat] into ! latt]1 by :i* means ! :ole mass gets wat]-logg$4 ,ne> ! ,lip>is & o!r volcanic isl&s ! sea is sometimes cov]$ ) fragm5ts ( pumice to su* an ext5t t x is difficult = a boat to make progress ?r\gh x1 & ! same sub/ance is frequ5tly f\nd float+ 9 ! op5 ocean & is ca/ up on e %ore4 ,dur+ ! ye> #ahgh masses ( float+ pumice 7 report$ z exi/+ 9 ! vic9ity ( ! ,solomon ,isles1 & cov]+ ! surface ( ! sea to su* ext5t t x took %ips ?ree days to =ce _! way ?r\gh !m4 ,sometimes ^! masses ( pumice accumulate 9 su* quantities along coa/s t x is difficult to det]m9e ! position ( ! %ore )9 a mile or two1 z we may l& & walk ab\t on ! great float+ raft ( pumice4 ,n[1 rec5t deep-sea s\nd+s1 c>ri$ on 9 ! ',*all5g]' & o!r vessels1 h %[n t ! bottom ( ! deepe/ portion ( ! ocean1 f> away f ! l&1 is cov]$ ) ^! volcanic mat]ials :i* h be5 c>ri$ ?r\gh ! air or float$ on ! surface ( ! ocean4 ,to ^! deep] p>ts ( ! ocean no s$im5ts c>ri$ d[n by ! riv]s are borne1 & ! rema9s ( calc>e\s organisms are1 9 ^! abysses1 soon dissolv$2 "u su* conditions1 !re=e1 almo/ ! only mat]ial accumulat+ on ! sea bottom is ! ubiquit\s w9d- & wave-borne volcanic products4 ,^! p>ticles ( volcanic du/ & fragm5ts ( pumice by _! dis9tegration give rise to a clayey mat]ial1 & ! oxidation ( ! magnetite1 :i* all lavas conta91 communicates to ! mass a r$di% t9t4 ,?is appe>s to be ! true orig9 ( ^? masses ( 'r$-clay' :i*1 accord+ to rec5t rese>*es1 are f\nd to cov] all ! deep] p>ts ( ! ocean1 b :i* probably atta9 to no great ?ickness4 ,b :ile "s portion ( ! mat]ials eject$ f volcanoes may ?us be c>ri$ by w9ds & waves1 s z to be disp]s$ ov] e "p ( ! l& & ! ocean-b$1 ano!r1 & 9 mo/ cases by f> ! l>ge/1 portion ( ^! ejections falls ar\nd ! volcanic v5t itself4 ,x is by ! con/ant accumulation ( ^! eject$ mat]ials t su* great m\nta9 masses z ,etna1 ,t5]iffe1 ,fusiyama1 & ,*imborazo h be5 gradually built up ar\nd c5tres ( volcanic action4 ,!re are cases 9 :i* ! =mation ( volcanic m\nta9s on a small scale has actually be5 obs]v$ by tru/wor?y witnesses4 ,!re are o!r cases 9 :i* volcanic m\nta9s ( l>g] size c be %[n to h increas$ 9 height & bulk by ! fall ^u _! sides & summits ( fragm5t>y mat]ials eject$ f ! volcanic v5t4 ,9 all cases ! exam9ation ( ^! m\nta9-masses leads to ! conclusion t !y are entirely built up ( j su* mat]ials z we con/antly see ?r[n out ( volcanoes dur+ eruption4 ,sid5ote3 ,,=mation ,,( ,,volcanic ,,m\nta9s4 ,?us we are l$ to ! conclusion t all volcanic m\nta9s are no?+ b heaps ( mat]ials eject$ f fissures 9 ! e>?'s cru/1 ! small] ones hav+ be5 =m$ dur+ a s+le volcanic outbur/1 ! l>g] ones be+ ! result ( repeat$ eruptions f ! same orifice :i* may1 9 "s cases1 h cont9u$ 9 action = t5s or hundr$s ( ?\s&s ( ye>s4 ,no obs]v] has done su* useful "w 9 connection ) ! /udy ( ! mode ( =mation ( volcanic m\nta9s z our c\ntryman1 ,sir ,william ,hamilton1 :o 0 ambassador at ,naples f #agfd to #ahjj1 & made ! be/ possible use ( 8 opportunities = exam9+ ! num]\s volcanoes 9 ,s\!rn ,italy4 ,a little to ! we/ ( ! t[n ( ,puzzuoli on ! ,bay ( ,naples !re /&s a conical hill ris+ to ! height ( #ddj feet above ! level ( ! ,m$it]ranean1 & cov]+ an area m ?an half a mile 9 diamet]4 ,n[ we h ! mo/ conclusive evid5ce t 9 anci5t times no su* hill exi/$ on ?is site1 :i* 0 p>tly occupi$ by ! ,lucr9e ,lake1 & ! fact is recognis$ 9 ! "n :i* ! hill be>s1 t ( ,monte ,nuovo1 or ! ',new ,m\nta94' ,see fig4 #aj4 ,sir ,william ,hamilton r5d]$ admirable s]vice to sci5ce by collect+ all ! contempor>y records relat+ to ?is int]e/+ case1 & he 0 able to prove1 by ! te/imony ( sev]al intellig5t & tru/wor?y witnesses1 t dur+ ! week foll[+ ! #bi? ( ,septemb]1 #aech1 ?is hill _h gradually be5 =m$ ( mat]ials eject$ f a volcanic v5t :i* _h op5$ ^u ?is site4 ,illu/ration3 ,fig4 #aj4 ,monte ,nuovo 7#ddj ft4 high7 on ! %ores ( ! ,bay ( ,naples4 ,sid5ote3 ,,hi/ory ,,( ,,! ,,=mation ,,( ,,monte ,,nuovo4 ,! records collect$ by ,hamilton ) o!rs :i* h be5 discov]$ s9ce 8 dea? prove mo/ conclusively ! foll[+ facts4 ,dur+ m ?an two ye>s1 ! c\ntry r\nd 0 affect$ by e>?quakes1 :i* gradually increas$ 9 int5sity & atta9$ _! climax 9 ! mon? ( ,septemb] #aech2 on ! #bg? & #bh? ( t mon? ^! e>?quake %ocks are said to h be5 felt almo/ cont9u\sly day & night4 ,ab\t #h o'clock on ! morn+ ( ! #bi?1 a depression ( ! gr\nd 0 notic$ on ! site ( ! future hill1 & f ?is depression1 wat]1 :i* 0 at fir/ cold & aft]w>ds tepid1 began to issue4 ,f\r h\rs aft]w>ds ! gr\nd 0 se5 to swell up & op51 =m+ a gap+ fissure1 )9 :i* inc&esc5t matt] 0 visible4 ,f ?is fissure num]\s masses ( /one1 "s ( !m 'z l>ge z an ox1' ) va/ quantities ( pumice & mud1 7 ?r[n3 up to a great height1 & ^! fall+ ^u ! sides ( ! v5t =m$ a great m\nd4 ,?is viol5t ejection ( mat]ials cont9u$ = two days & nights1 & on ! ?ird day a v consid]able hill 0 se5 to h be5 built up by ! fall+ fragm5ts1 & ?is hill 0 climb$ by "s ( ! eye-witnesses ( ! eruption4 ,! next day ! ejections 7 resum$1 & _m p]sons :o _h v5tur$ on ! hill 7 injur$1 & sev]al kill$ by ! fall+ /ones4 ,! lat] ejections 7 h[ev] ( less viol5ce ?an ! e>li] ones1 & seem to h di$ out on ! sev5? or eigh? day aft] ! beg9n+ ( ! outbur/4 ,! great mass ( ?is consid]able hill w\ld appe>1 accord+ to ! acc\nts :i* h be5 pres]v$1 to h be5 built up by ! mat]ials :i* 7 eject$ dur+ two days & nights4 ,monte ,nuovo is a hill ( truncat$ conical =m1 :i* rises to ! height ( #ddj feet above ! wat]s ( ! ,m$it]ranean1 & is n[ cov]$ ) ?ickets ( /one-p9e4 ,! hill is entirely made up ( volcanic scori1 lapilli1 & du/1 & ! slop+ sides h evid5tly be5 produc$ by ^! fragm5t>y mat]ials slid+ ov] "o ano!r till !y atta9$ ! angle ( re/2 j z happ5s ) ! e>? & /ones tipp$ f railway-waggons dur+ ! con/ruction ( an embankm5t4 ,9 ! c5tre ( ?is conical hill is a va/ circul> depression1 ) /eeply slop+ sides1 :i* is ( su* dep? t its bottom is b little above ! sea-level4 ,?is cup-%ap$ depression is ! 'crat]' ( ! volcano1 & x has evid5tly be5 =m$ by ! explosive action :i* has ?r[n out ! mat]ials imm$iately above ! v5t1 & caus$ !m to be accumulat$ ar\nd x4 ,illu/ration3 ,fig4 #aa4--,map ( ! di/rict ar\nd ,naples1 %[+ ,monte ,nuovo & ! surr\nd+ volcanoes ( old] date4 ,! di/rict ly+ to ! we/ ( ,naples1 9 :i* ! ,monte ,nuovo is situat$1 conta9s a great numb] ( hills1 all ( :i* pres5t a mo/ /rik+ simil>ity to t volcano4 ,all ^! hills are truncat$ cones1 ) l>g] or small] circul> depressions at _! summits1 & !y axe entirely compos$ ( volcanic scori1 lapilli1 & du/4 ,"s ( ^! hills are ( consid]ably l>g] dim5sions ?an ! ,monte ,nuovo1 :ile o!rs are ( small] size1 z %[n 9 ! annex$ map1 fig4 #aa4 ,no /rang] visit+ ! di/rict1 )\t previ\s in=mation ^u ! subject1 w\ld ev] suspect ! fact t1 :ile all ! o!r hills ( ! di/rict h exi/$ f "t immemorial1 & are con/antly m5tion$ 9 ! works ( ,greek & ,roman writ]s1 ?is p>ticul> hill ( ,monte ,nuovo came into exi/5ce less ?an #cej ye>s ago4 ,sid5ote3 ,,old] ,,volcanoes ,,( ,,! ,,campi ,,phlegr,i4 ,! evid5tly fus$ condition ( ! mat]ials ( :i* ^! hills are built up is a de> sign ( ! volcanic action :i* has tak5 place 9 x2 & ?is feet 0 s fully recognis$ by ! anci5ts t !y call$ ! di/rict ! ,campi ,phlegri1 or '! ,burn+ ,fields1' & reg>d$ "o ( ! circul> depressions 9 x z ! entrance to ,hades4 ,x is impossible = anyone to exam9e ?is di/rict )\t be+ conv9c$ t all ! num]\s cones & crat]s :i* cov] x h be5 =m$ by ! same ag5cy z t by :i* ,monte ,nuovo 0 produc$4 ,we h %[n t !re is ! mo/ satisfactory hi/orical evid5ce z to :at t ag5cy 04 ,n[ volcanic cones ) crat]s 9 _! c5tres occur 9 great numb]s 9 _m p>ts ( ! e>?'s surface4 ,9 "s di/ricts1 l ! ,auv]gne1 ! ,catacecaum5e 9 ,asia ,m9or1 & c]ta9 p>ts ( ,new ,zeal&1 ^! volcanic cones occur by hundr$s & ?\s&s4 ,9 "s in/ances1 ^! volcanic cones h be5 =m$ 9 hi/oric times1 b 9 ! great majority ( cases we c only inf] _! mode ( orig9 f _! simil>ity to o!rs ( :i* ! =mation has be5 witness$4 ,mo/ ( ! small] volcanic hills1 ) _! crat]s1 h be5 ?r[n up dur+ a s+le eruption f a volcanic fissure2 b1 z ,hamilton conclusively prov$1 ! gr&e/ volcanic m\nta9s mu/ h be5 produc$ by frequ5t repetitions ( simil> op]ations ^u ! same site4 ,= n only are ^! great volcanic piles f\nd to be entirely compos$ ( mat]ials :i* h evid5tly be5 eject$ f volcanic v5ts1 b1 :5 c>efully wat*$1 su* m\nta9s are f\nd und]go+ cont9ual *anges 9 =m1 by ! addition ( mat]ials ?r[n out f ! v5t1 & fall+ ^u _! sides4 ,?is fact w be well illu/rat$ by a comp>ison ( ! s]ies ( draw+s ( ! summit ( ,vesuvius :i* 7 made by ,sir ,william ,hamilton 9 #agfg1 & :i* we h copi$ 9 fig4 #ab4 ,dur+ ! e>li] mon?s ( t ye> ! summit ( ! m\nta9 0 se5 to be ( truncat$ =m1 a great crat] hav+ be5 orig9at$ by ! viol5t outbur/s ( ! prec$+ ye>4 ,?is condition ( ! m\nta9-top is repres5t$ 9 ! fir/ figure ( ! s]ies4 ,! draw+ made by ,hamilton1 on ,july #h1 %[s t n only 0 ! out] rim ( ! great crat] be+ modifi$ 9 =m by ! fall ( mat]ials ^u x1 b t 9 ! c5tre ( ! crat] a small cone 0 be+ gradually built up by ! quiet ejections :i* 7 tak+ place4 ,illu/ration3 ,fig4 #ab4--,outl9es ( ! ,summit ( ,vesuvius dur+ ! ,eruption ( #agfg4 ,sid5ote3 ,,*anges ,,9 ,,=m ,,( ,,vesuvius4 ,if we comp>e ! draw+s made at successive dates1 we %all f9d t ! con/ant %[]s ( fall+ mat]ials 7 n only rais+ ! edge ( ! great crat] b 7 at ! same "t increas+ ! size ( ! small cone inside ! crat]4 ,by ! end ( ,octob] ! small cone _h gr[n to su* an ext5t t its sides 7 conflu5t ) ^? ( ! pr9cipal cone1 :i* _h ?us entirely lo/ its truncat$ =m & be5 rais$ to a mu* great] height4 ,! comp>ison ( ^! draw+s w be facilitat$ by ! dott$ l9es1 :i* repres5t ! outl9e ( ! top ( ! m\nta9 at ! prec$+ obs]vation2 s t ! space betwe5 ! dott$ & ! cont9u\s l9e 9 ea* draw+ %[s ! ext5t to :i* ! bulk ( ! cone _h increas$ 9 ! int]val betwe5 two obs]vations4 ,b1 al?\gh ! g5]al t5d5cy ( ! action go+ on at volcanic m\nta9s is to increase _! height & bulk by ! mat]ials fall+ ^u _! summits & aides1 x mu/ be rememb]$ t ?is action does n take place by any means cont9u\sly & regul>ly4 ,n only are !re p]iods ( re/ 9 ! activity ( ! volcano1 dur+ :i* ! ra9 & w9ds may accompli% a great deal 9 ! way ( crumbl+ d[n ! loose mat]ials ( :i* volcanic m\nta9s are l>gely built up1 b sudd5 & viol5t eruptions may 9 a v %ort "t undo ! sl[ "w ( ye>s by bl[+ away ! :ole summit ( ! m\nta9 at once4 ,?us1 be=e ! great eruption ( #ahbb1 ! cone ( ,vesuvius1 by ! almo/ con/ant ejection ( a%es dur+ sev]al ye>s1 _h be5 rais$ to ! height ( m ?an #d1jjj feet above ! level ( ! sea2 b by ! t]rible outbur/ :i* !n took place ! cone 0 r$uc$ 9 height by #djj feet1 & a va/ crat]1 :i* _h a diamet] ( ne>ly a mile1 & a dep? ( ne>ly #a1jjj feet 7see fig4 #ac71 0 =m$ at ! top ( ! m\nta94 ,! enorm\s quantity ( mat]ial ?us remov$ 0 ei!r di/ribut$ ov] ! flanks ( ! m\nta91 or1 :5 r$uc$ to a f9ely comm9ut$ condition1 0 c>ri$ by ! w9d to ! di/ance ( _m miles1 d>k5+ ! air1 & coat+ ! surface ( ! gr\nd ) a ?ick cov]+ ( du/4 ,illu/ration3 ,fig4 #ac4--;,crat] ( ,vesuvius =m$ dur+ ! eruption 9 #ahbb4 7,x 0 ne>ly #a mile 9 diamet] & #a1jjj ft4 deep47 ,sid5ote3 ,,e>ly ,,hi/ory ,,( ,,vesuvius4 ,! volcano ( ,vesuvius1 al?\gh ( some:at insignificant dim5sions :5 comp>$ ) ! gr&] volcanic m\nta9s ( ! globe1 possesses great int]e/ = ! /ud5t ( ,vulcanology1 inasmu* z be+ situat$ 9 ! mid/ ( a ?ickly populat$ di/rict & 9 close proximity to ! city ( ,naples1 x has attract$ mu* att5tion dur+ pa/ times1 & !re is no o!r volcano conc]n+ :i* we h s complete a s]ies ( hi/orical records4 ,! pres5t cone ( ,vesuvius1 :i* rises )9 ! great encircl+ crat]-r+ ( ,somma1 has a height ( ab\t #a1jjj feet4 ,b !re is und\bt$ evid5ce t ?is cone1 to ! top ( :i* a railway has rec5tly be5 con/ruct$ = ! conv5i5ce ( t\ri/s1 has be5 entirely built up dur+ ! la/ #a1hjj ye>s1 &1 :at is m1 t dur+ ?is p]iod x has be5 _m times almo/ :olly de/roy$ & recon/ruct$4 ,no?+ is m c]ta9 ?an ! bet t ! ,vesuvius ^u :i* ! anci5t ,romans & ! ,greek settl]s ( ,s\!rn ,italy look$1 0 a m\nta9 diff]+ entirely 9 its =m & appe>ance f t ) :i* we are famili>4 ,! ,vesuvius kn[n to ! anci5ts 0 a great truncat$ cone1 hav+ a diamet] at its base ( eight or n9e miles1 & a height ( ab\t #d1jjj feet4 ,! summit ( ?is m\nta9 0 =m$ by a circul> depress$ pla91 ne>ly ?ree miles 9 diamet]1 )9 :i* ! gladiator ,sp>tacus1 ) 8 foll[]s1 7 besieg$ by a ,roman army4 ,!re is no evid5ce t at ?is "t ! volcanic "* ( ! m\nta9 0 g5]ally recognis$1 & its slopes are describ$ by ! anci5t geograph]s z be+ clo!d ) f]tile fields & v9ey>ds1 :ile ! holl[ at ! top 0 a wa/e ov]gr[n ) wild v9es4 ,illu/ration3 ,fig4 #ad4--;,crat] ( ,vesuvius 9 #agef4 7,f a draw+ made on ! spot7 ,b 9 ! ye> #gi a t]rible & unexpect$ eruption occurr$1 by :i* a va/1 crat]al holl[ 0 =m$ 9 ! mid/ ( ,vesuvius1 & all ! s\!rn side ( ! great rim surr\nd+ ?is crat] 0 brok5 d[n4 ,"u ! mat]ials eject$ dur+ ?is eruption1 ! cities ( ,pompeii1 ,h]culaneum1 & ,/abi 7 ov]:elm$ & buri$4 ,num]\s descriptions & draw+s enable u to und]/& h[ 9 ! mid/ ( ! va/ crat] =m$ 9 ! ye> #gi ! mod]n cone has gradually be5 built up4 ,fre% eruptions are cont9ually increas+ ! bulk1 or rais+ ! height ( ! ,vesuvian cone4 ,! accompany+ draw+s made by ,sir ,william ,hamilton enable u to und]/& ! nature ( ! *anges :i* h be5 cont9ually tak+ place at ! summit ( ,vesuvius4 ,! draw+ fig4 #ad %[s ! appe>ance pres5t$ by ! crat] 9 ! ye> #agef4 ,illu/ration3 ,fig4 #ae4--,! ,summit ( ,vesuvius 9 #agfg4 7,f an orig9al draw+47 ,sid5ote3 ,,vesuvius ,,9 ,,mod]n ,,times4 ,at ?is "t we see t inside ! crat] a s]ies ( cones _h be5 built up "o )9 ! o!r f :i* lava issu$1 fill+ ! bottom ( ! crat] & f9d+ its way ?r\gh a brea* 9 its walls1 d[n ! side ( ! cone4 ,x is evid5t t ! eject$ mat]ials fall+ on ! sides ( ! inn]mo/ cone w\ld t5d to enl>ge ! latt] till its sides became conflu5t ) ! cone surr\nd+ x1 & if ?is action w5t on long en\gh1 ! crat] w\ld be entirely fill$ up & a p]fect cone ) only a small ap]ture at ! top w\ld be produc$4 ,b f "t to "t1 gr& & p>oxysmal outbur/s h occurr$ at ,vesuvius1 :i* h truncat$ ! cone1 & sometimes =m$ great1 cup-%ap$ cavities1 rea*+ almo/ to its base1 l t %[n 9 fig4 #ac4 ,9 #agfg ! crat] ( ,vesuvius1 z %[n 9 fig4 #ae1 conta9$ a s+le small cone 9 a /ate ( con/ant spasmodic outbur/1 l t ( ,/romboli4 ,illu/ration3 ,fig4 #af4--,summit ( ,vesuvius 9 #ahdh4 ,9 #ahdc1 we f9d t ! crat] ( ,vesuvius conta9$ ?ree su* small cones arrang$ 9 a l9e along its bottom z depict$ 9 fig4 #af4 ,^! draw+s ( ! summit ( ,vesuvius give a fair notion ( ! *anges :i* h be5 cont9ually go+ on !re dur+ ! :ole ( ! hi/orical p]iod4 ,ev] & anon a gr& outbur/1 l t ( #ahbb1 has produc$ a va/ & deep crat] su* z is repres5t$ 9 fig4 #ac1 & !n a long cont9uance ( quiet & regul> ejections has built up )9 ! crat] small cones l ^? %[n 9 figs4 #ad1 #ae & #af1 till at la/ ! great crat] has be5 completely fill$ up1 & ! cone recon/ruct$4 ,illu/ration3 ,fig4 #ag4--,outl9es ( ,vesuvius1 %[+ its ,=m at diff]5t p]iods ( its hi/ory4 ,sid5ote3 ,,*anges ,,9 ,,outl9e ,,( ,,vesuvius4 ,9 ! s]ies ( outl9es 9 fig4 #ag1 we h endeav\r$ to illu/rate ! succession ( *anges :i* has tak5 place 9 ,vesuvius dur+ hi/orical times4 ,9 ! ye> #gi "o side ( ! crat]-wall ( ! va/ m\nta9-mass 0 bl[n away4 ,subsequ5t ejections built up ! pres5t cone ( ,vesuvius )9 ! great encircl+ crat]-wall ( ,somma1 & ! =m ( ?is cone & ! crat] at its summit h be5 und]go+ cont9ual *anges dur+ ! successive eruptions ( eighte5 c5turies4 ,:at its future hi/ory may be we c only conjecture f analogy4 ,x may be t a long cont9uance ( eruptions ( mod]ate en]gy may gradually raise ! c5tral cone till its sides are conflu5t ) ^? ( ! orig9al m\nta92 or x may be t "s viol5t p>oxysm w entirely de/roy ! mod]n cone1 r$uc+ ! m\nta9 to ! condition 9 :i* x 0 aft] ! great outbur/ ( #gi4 ,on ! o!r h&1 if ! volcanic =ces "u ,vesuvius are gradually becom+ ext9ct 7b ( ?is we h c]ta9ly no evid5ce at pres5t71 ! m\nta9 may gradually s9k into a /ate ( quiesc5ce1 reta9+ its exi/+ =m4 ,! s]ies ( *anges 9 ! %ape ( ,vesuvius1 :i* are prov$ by docum5t>y evid5ce to h be5 go+ on dur+ ! la/ #b1jjj ye>s1 probably f9d _! p>allel 9 all active volcanoes4 ,9 all ( ^!1 z we %all h]eaft] %[1 ! activity ( ! v5ts und]goes great vicissitudes4 ,p]iods ( cont9u\s mod]ate activity alt]nate ) %ort & viol5t p>oxysmal outbur/s & int]vals ( complete re/1 :i* may 9 "s cases la/ = hundr$s or ev5 ?\s&s ( ye>s4 ,dur+ ! p]iods ( cont9u\s mod]ate activity1 ! crat] ( ! volcano is sl[ly fill$ up by ! gr[? ( small] cones )9 x2 & ! height ( ! m\nta9 is rais$4 ,by ! t]rible p>oxysmal outbur/s ! m\nta9 is (t5 completely gutt$ & its summit bl[n away2 b ! mat]ials ?us remov$ f ! top & c5tre ( ! mass are = ! mo/ "p spread ov] its aides1 s t its bulk & ! area ( its base are !reby increas$4 ,dur+ ! int]vals ( re/1 ! sides ( ! m\nta9 :i* are s l>gely compos$ ( loose & pulv]ul5t mat]ials are wa%$ d[nw>ds by ra9s & driv5 ab\t by w9ds4 ,?us all volcanoes 9 a /ate ( activity are cont9ually gr[+ 9 size e ejection1 except 9 ! case ( ^? :]e ! mat]ials are 9 ! f9e/ /ate ( subdivision1 add+ to _! bulk2 ! area ( _! bases be+ increas$ dur+ p>oxysmal outbur/s1 & _! height dur+ long-cont9u$ mod]ate eruptions4 ,sid5ote3 ,,deviations ,,f ,,conical ,,=m4 ,we h po9t$ out t ! conical =m ( volcanic m\nta9s is due to ! slipp+ ( ! fall+ mat]ials ov] "o ano!r till !y atta9 ! angle at :i* !y c re/4 ,!re are1 h[ev]1 "s deviations f ?is regul> conical =m ( volcanoes :i* x may be well to ref] to4 ,! quantity ( ra9 :i* falls dur+ volcanic eruptions is (t5 enorm\s1 ow+ to ! cond5sation ( ! great volumes ( /eam emitt$ f ! v5t4 ,consequ5tly ! fall+ lapilli & du/ (t5 desc5d ^u ! m\nta91 n 9 a dry /ate b 9 ! condition ( a muddy pa/e4 ,_m volcanic m\nta9s h evid5tly be5 built up by ! fl[ ( successive masses ( su* muddy pa/e ov] _! surfaces4 ,"s volcanic mat]ials :5 mix$ ) wat] h ! prop]ty ( rapidly 'sett+' l concrete4 ,! anci5t ,romans & mod]n ,italians1 well acqua9t$ ) ?is prop]ty ( c]ta9 k9ds ( volcanic du/ & lapilli1 h 9 all ages employ$ ?is 'puzzolana1' z x is call$1 z mort> = build+4 ,! volcanic muds h (t5 set 9 _! natural positions1 s z to =m a rock1 :i*1 ?\gh light & por\s1 is ( tol]ably firm consi/5cy4 ,to ?is k9d ( rock1 ( :i* ,naples & _m o!r cities are built1 ! "n ( 'tuff' or 'tufa' is appli$4 ,a simil> mat]ial is kn[n 9 ,nor!rn ,g]many z 'trass4' ,! cause ( ! 'sett+' ( puzzolana & tufa is t ra9-wat] conta9+ a small proportion ( c>bonic acid acts on ! lime 9 ! volcanic fragm5ts1 & ^! become cem5t$ toge!r by ! c>bonate ( lime & ! free silica1 :i* are ?us produc$ 9 ! mass4 ,:5 a /rong w9d is bl[+ dur+ a volcanic outbur/1 ! mat]ials may be driv5 to "o side ( ! v5t1 & accumulate !re m rapidly ?an on ! o!r4 ,?us lop-sid$ cones are =m$1 su* z may frequ5tly be obs]v$ 9 "s volcanic di/ricts4 ,9 areas :]e con/ant curr5ts ( air1 l ! trade-w9ds1 prevail1 all ! scoria-cones ( ! di/rict may ?us be f\nd to be unequally develop$ on opposite sides1 be+ l[e/ on ^? f :i* ! preval5t w9ds bl[1 & highe/ on ! sides t[>ds :i* ^! w9ds bl[4 ,sid5ote3 ,,angle ,,( ,,slope ,,9 ,,volcanic ,,cones4 ,! exam9ation ( any c>eful draw+1 or bett] /ill ( ! photograph1 ( a volcanic cone1 w prove t ! pr(ile ( su* cones is n =m$ by /raight l9es1 b by curves (t5 ( a delicate & beautiful "*4 ,! del9eations ( ! sacr$ volcano ( ,fusiyama1 :i* are s con/antly f\nd 9 ! productions ( ,japanese arti/s1 mu/ h famili>is$ ev]yone ) ! elegant curv$ l9es exhibit$ by ! pr(iles ( volcanoes4 ,! upp] slope ( ! m\nta9 is comp>atively /eep1 (t5 exhibit+ angles ( #cj to #ce1 b ?is /eepness ( slope gradually dim9i%es1 till x ev5tually m]ges 9 ! surr\nd+ pla9s4 ,! cause ( ?is elegant =m assum$ by mo/ volcanic m\nta9s is probably two-fold4 ,9 ! fir/ place we h to rememb] t ! mat]ials fall+ ^u ! flanks ( ! m\nta9 diff] 9 size & %ape1 & "s w re/ on a /eep] slope ?an o!rs4 ,?us1 :ile "s ( ! mat]ials rema9 on ! upp] "p ( ! m\nta9s1 o!rs are roll+ outw>ds & d[nw>ds4 ,h5ce we f9d t ^? cones :i* are compos$ ( uni=m mat]ials h /raight sides4 ,b 9 "s cases1 we %all see h]eaft]1 !re has c]ta9ly be5 a c5tral subsid5ce ( ! m\nta9 mass1 & x is ?is subsid5ce :i* has probably giv5 rise to ! curvature ( its flanks4 ,we h hi!rto consid]$ only ! me?ods by :i* ! fro? or foam1 :i* accumulates on ! surface ( fluid lava1 is disp]s$4 ,b 9 _m cases n only is ?is scum ( ! lava eject$ f ! volcanic v5t by ! escap+ /eam1 b ! fluid lava itself is extrud$ =cibly1 & (t5 9 enorm\s quantities4 ,! lava 9 a volcanic v5t is always 9 a highly heat$1 usually inc&esc5t1 condition4 ,se5 by night1 its fre%ly expos$ surface is gl[+ r$1 sometimes app>5tly :ite-hot4 ,b by exposure to ! atmosph]e ! surface is rapidly *ill$1 appe>+ dull r$ by night1 & black by day4 ,_m p]sons are surpris$ to f9d t a fl[+ /ream ( lava pres5ts ! appe>ance ( a great mass ( r\gh c9d]s1 roll+ along ) a rattl+ s\nd1 ow+ to ! /rik+ ( ! cl9k]-l fragm5ts aga9/ ea* o!r4 ,:5 view$ by night1 ! gleam+1 r$ light betwe5 ^! r\gh1 c9d]y masses betrays ! pres5ce ( inc&esc5t mat]ials bel[ ! *ill$ surface ( ! lava-/ream4 ,no fact 9 connection ) lavas is m /rik+ ?an ! v>y+ degrees ( liquidity pres5t$ by !m 9 diff]5t cases4 ,:ile "s lava-/reams seem to resemble riv]s1 ! mat]ial fl[+ rapidly along1 fill+ e *annel 9 its c\rse1 & delug+ ! :ole c\ntry ar\nd1 o!rs w\ld be m fitly comp>$ to glaci]s1 creep+ along at s sl[ a rate t ! fact ( _! movem5t c only be demon/rat$ by ! mo/ c>eful obs]vation4 ,ev5 :5 fall+ ov] a precipice su* lavas1 ow+ to _! imp]fect liquidity1 =m heavy1 p5d5t masses l a 'gutt]+' c&le1 z is %[n by fig4 #ah1 :i* is tak5 f a draw+ k9dly furni%$ to me by ,capt4 ,s4 ,p4 ,oliv]1 ,r4,a4 ,! causes ( ^! diff]5ces 9 ! rate ( motion ( lava-/reams we mu/ proce$ to consid]4 ,illu/ration3 ,fig4 #ah4--;,cascade ( ,lava tumbl+ ov] a cliff 9 ! ,isl& ( ,b\rbon4 ,sid5ote3 ,,temp]ature ,,( ,,lava-,,/reams4 ,!re c be no d\bt t ! temp]ature ( lavas v>ies greatly 9 diff]5t cases4 ,?is is %[n by ! fact t :ile "s lavas are 9 a /ate ( complete fusion1 simil> to t ( ! slags ( furnaces1 & l ! latt]1 su* lavas on cool+ =m a glassy mass1 o!rs consi/ ( a liquid magma 9 :i* a l>g] or small] numb] ( cry/als are f\nd float+4 ,9 ^! latt] cases ! temp]ature ( ! magma mu/ be bel[ ! fus+-po9t ( ! m9]als :i* exi/ 9 a cry/all9e condition 9 its mid/4 ,x has inde$ be5 sugge/$ t ! :ole ( ! cry/als 9 lavas are =m$ dur+ ! cool+ d[n ( a completely fus$ mass2 b no "o c imag9e t ! enclos$ cry/als ( qu>tz1 felsp>1 leucite1 oliv9e1 c41 h be5 s =m$1 su* cry/als be+ sometimes m ?an an in* 9 diamet]4 ,! microscopic exam9ation ( lavas usually enables u to discrim9ate betwe5 ^? complete cry/als :i* h be5 =m$ at great dep?s & c>ri$ up to ! surface1 & ! m9ute cry/all9e p>ticles & microli?s :i* h be5 develop$ 9 ! glassy mass dur+ cool+4 ,cry/als ( ! =m] class1 inde$1 exhibit abundant evid5ce1 9 _! liquid cavities & o!r peculi>ities1 t !y h n be5 =m$ by simple cool+ f a /ate ( fusion1 b "u ! comb9$ action ( heat1 ! pres5ce ( wat] & v>i\s gases1 & int5se pressure4 ,z we h already se51 ! diff]5t lavas v>y greatly 9 _! degrees ( fusibility4 ,! basic lavas1 conta9+ a l[ p]c5tage ( silica1 are mu* m fusible ?an ! acid lavas1 :i* conta9 a high p]c5tage ( silica4 ,:5 ! basic lavas are r$uc$ to a complete /ate ( fusion _! liquidity is sometimes v p]fect1 z is ! case at ,kilauea 9 ,hawaii1 :]e ! lava is ?r[n up into jets & f\nta9s1 fall+ 9 m9ute drops1 & be+ drawn out into f9e glassy ?reads4 ,on ! o!r h&1 ! less fusible acid lavas appe> to be usually only r$uc$ to ! visc\s or pa/y condition1 :i* artificial glasses assume long be=e _! complete fusion4 ,( ?is fact ,i h f\nd _m pro(s 9 ! ,lip>i ,isl&s1 :]e su* glassy1 acid lavas ab\nd4 ,9 fig4 #f 7page #dc7 a lava-/ream is repres5t$ on ! side ( ! cone ( ,vulcano4 ,sid5ote3 ,,imp]fectly ,,fluid ,,lavas4 ,?is lava is an obsidian--t is to say1 x is ( ! add type & completely glassy--b its liquidity mu/ h be5 v imp]fect1 see+ t ! /ream has come to a /&/ill be=e rea*+ ! bottom ( a /eep slope ( ab\t #ce4 ,9 fig4 #ai !re is giv5 a side view ( ! same /ream ( obsidian1 f :i* x w be se5 t x has fl[$ sl[ly d[n a /eep slope & heap$ itself up at ! bottom1 z its fluidity 0 n complete en\gh to enable x to move on a slight] incl9e4 ,an exam9ation ( ! int]ior ( su* imp]fectly fluid lavas af=ds fre% pro(s ( ! sl[ & tortu\s movem5ts ( ! mass4 ,ev]y:]e we f9d t ! b&s ( cry/allites & sphrulites are1 by ! movem5t ( ! mass1 fold$ & crumpl$ & puck]$ 9 ! mo/ rem>kable mann]1 z is illu/rat$ 9 figs4 #bj & #ba4 ,simil> appe>ances occur aga9 & aga9 among ! vitre\s & semi-vitre\s acid lavas ( ,hung>y4 ,illu/ration3 ,fig4 #ai4--,lava-/ream 7obsidian7 9 ! ,isl& ( ,vulcano %[+ ! imp]fect liquidity ( ! mass4 ,illu/ration3 ,fig4 #bj4--;,int]ior ( a ,rhyolitic ,lava-/ream 9 ! ,isl& ( ,lip>i1 %[+ broad sigmoidal folds produc$ by ! sl[ movem5ts ( ! mass4 ,illu/ration3 ,fig4 #ba4--;,int]ior ( a ,rhyolitic ,lava-/ream 9 ! ,isl& ( ,lip>i1 %[+ ! complicat$ crumpl+s & puck]+s produc$ by ! sl[ movem5ts ( ! mass4 ,sid5ote3 ,,rate ,,( ,,movem5t ,,( ,,vesuvian ,,lavas4 ,b1 al?\gh ! temp]ature ( lava-/reams & ! fusibility ( _! mat]ials may 9 "s cases acc\nt = _! condition ( ei!r p]fect liquidity or viscidity1 x is cle> t 9 o!r in/ances !re mu/ be "s o!r cause = ?is diff]5ce4 ,?us x has be5 f\nd t at ,vesuvius ! lavas erupt$ 9 mod]n times h all a /rik+ simil>ity to "o ano!r 9 *emical composition1 9 ! m9]als :i* !y conta91 & 9 _! /ructure4 ,!y are all basic lavas1 :i* :5 exam9$ by ! microscope are se5 to consi/ ( a m or less glassy magma1 9 ! mid/ ( :i* num]\s cry/als ( augite1 leucite1 oliv9e1 magnetite1 & o!r m9]als are scatt]$4 ,yet no?+ c be m /rik+ly diff]5t ?an ! behavi\r ( ! lavas p\r$ out f ,vesuvius at v>i\s p]iods4 ,9 "s cases ! lava appe>s to be 9 su* a p]fectly liquid condition t1 issu+ f ! crat]1 x has be5 describ$ z ru%+ d[n ! slope ( ! cone l a /ream ( wat]1 & su* exce$+ly liquid lavas h 9 "s cases fl[$ to ! di/ance ( sev]al miles f ! base ( ! m\nta9 9 a v %ort "t4 ,b o!r ,vesuvian lavas h be5 9 su* a viscid condition t _! rate ( movem5t has be5 s extremely sl[ z to be almo/ imp]ceptible4 ,su* lava-/reams h cont9u$ 9 movem5t dur+ _m ye>s1 b ! progress has be5 s sl[ 7(t5 only a few in*es 9 a day7 t x c\ld only be prov$ by means ( c>eful measurem5ts4 ,if we exam9e "s ( ^! ,vesuvian lavas :i* h exhibit$ su* /rik+ diff]5ces 9 _! rate ( fl[1 we %all f9d t !y pres5t equally m>k$ diff]5ces 9 ! "* ( _! surfaces4 ,! lava-curr5t ( #aheh 0 a rem>kable example ( a sl[-fl[+ /ream1 & its surface1 z w be se5 9 fig4 #bb1 :i* is tak5 f a photograph1 has a v m>k$ & peculi> "*4 ,a t5aci\s cru/ seems to h =m$ on ! surface1 & by ! fur!r motion ( ! mass ?is cru/ or scum has be5 wr9kl$ & fold$ 9 a v rem>kable mann]4 ,sometimes ?is fold$ & twi/$ cru/ pres5ts a /rik+ resemblance to coils ( rope4 ,precisely simil> appe>ances may be obs]v$ on ! surface ( _m artificial slags :5 !y fl[ f furnaces1 & are se5 to be due to ! same cause1 namely1 ! wr9kl+ up ( ! *ill$ surface-cru/ by ! movem5t ( ! liquid mass bel[4 ,lavas :i* pres5t ?is appe>ance are frequ5tly call$ 'ropy lavas'2 an admirable example ( !m is af=d$ 9 ! lava-cascade ( ! ,isl& ( ,b\rbon repres5t$ 9 fig4 #ah 7page #ic74 ,b lavas 9 :i* ! rate ( fl[ has be5 v rapid1 exhibit q a diff]5t k9d ( surface to t ( ! ropy lavas4 ,! ,vesuvian lava-/ream ( #ahgb 0 rem>kable = ! rapidity ( its fl[1 & its surface pres5ts a rem>kable contra/ to t ( ! sl[-mov+ lava ( #aheh4 ,! surface ( ! lava-curr5t ( #ahgb is cov]$ ) r\gh c9d]y masses1 (t5 ( enorm\s dim5sions1 & x is exce$+ly difficult to trav]se x1 z ! ragg$ project+ fragm5ts te> ! boots & lac]ate ! sk94 ,! appe>ance pres5t$ by ?is lava-/ream is illu/rat$ by fig4 #bc1 :i* is also tak5 f a photograph4 ,illu/ration3 ,fig4 #bb4--,vesuvian ,lava-/ream ( #aheh1 exhibit+ ! peculi> ',ropy' ,surfaces ( ,sl[ly ,mov+ ,curr5ts4 7,f a ,photograph47 ,illu/ration3 ,fig4 #bc4--,vesuvian ,lava-/ream ( #ahgb1 exhibit+ ! ,r\gh ,c9d]y ,surfaces *>act]i/ic ( ,rapidly ,fl[+ ,curr5ts4 7,f a ,photograph47 ,sid5ote3 ,,vesuvian ,,lava-,,/ream ,,( #ahgb4 ,n[ x is f\nd t ^? lava-/reams :i* move sl[ly & pres5t ropy surfaces give (f b little /eam dur+ _! fl[1 :ile ^? lava-/reams :i* fl[ m rapidly & pres5t a r\gh & c9d]y appe>ance give (f va/ quantities ( /eam4 ,! extraord9>y am\nt ( vap\r giv5 (f f ! lava-/reams :i* fl[$ f ,vesuvius 9 #ahgb is illu/rat$ 9 ! photograph copi$ 9 fig4 #e 7fac+ page #bd71 9 :i* ! ?ree lava-curr5ts are ea* se5 to be surm\nt$ by enorm\s vap\r-cl\ds ris+ to ! height ( sev]al ?\s&s ( feet above !m1 & m+l+ ) ! column t issu$ f ! c5tral v5t4 ,by ! escape ( ?is enorm\s quantity ( /eam ! surface ( ! lava 0 ?r[n into rugg$ c9d]y projections1 & 9 "s places little cones 7 =m$ ^u x1 :i* ?rew out small scori & du/4 ,! quantity ( vap\r 01 9 fact1 s great1 t little p>asitical volcanoes 7 =m$ on ! surface ( ! lava-/ream4 ,"s ( ^! m9iature volcanoes 7 ( su* small dim5sions t !y 7 c>ri$ away on bo>ds to be employ$ z illu/rations 9 ! lecture-rooms ( ! ,univ]sity ( ,naples4 ,! arrangem5t ( ! mat]ials =c$ out f fissures on ! surfaces ( lava-/reams by ! dis5gag$ vap\rs & gases dep5ds on ! degree ( fluidity ( ! lava1 & ! =ce ( ! escap+ /eam-jets4 ,9 v visc\s lavas ! mat]ials may issue quietly1 =m+ great conc5tric masses l coils ( rope2 su* 7 describ$ by ,mr4 ,heaphy z occurr+ 9 ,new ,zeal& 7see fig4 #bd74 ,illu/ration3 ,fig4 #bd4--;,conc5tric ,folds on mass ( cool$ ,lava4 ,9 o!r cases ! lava1 if some:at m liquid1 may 9 issu+ quietly )\t great outbur/s ( /eam1 accumulate 9 great bottle-%ap$ masses1 :i* h be5 comp>$ to 'petrifi$ f\nta9s4' ,cases ( ?is k9d h be5 describ$ by ,pr(essor ,dana z occurr+ on ! slopes ( ,hawaii 7see fig4 #be74 ,illu/ration3 ,fig4 #be4--,mass ( cool$ ,lava =m$ ov] a spiracle on ! slopes ( ,hawaii4 ,sid5ote3 ,,m9iature ,,cones ,,on ,,lava-,,/reams4 ,:5 ! /eam escapes ) explosive viol5ce f a spiracle 7'bocca'7 on ! surface ( a lava-/ream1 m9ute c9d] cones1 l ^? describ$ z be+ =m$ 9 #ahgb1 are ! result4 ,fig4 #bf repres5ts a gr\p ( m9iature cones ?r[n up on ! ,vesuvian lava-/ream ( #ahee3 x is tak5 f a draw+ by ,s*midt4 ,illu/ration3 ,fig4 #bf4--;,gr\p ( small ,cones ?r[n up on ! ,vesuvian ,lava-curr5t ( #ahef4 ,"s ( ^! appe> l bur/ bli/]s or bubbles1 :ile o!rs are built up ( scoriace\s masses :i* h be5 eject$ f ! ap]ture & h become unit$ :ile 9 a semi-fluid condition4 ,o!r examples ( ^! spiracles or boc*e on ! surfaces ( lava-curr5ts may be se5 9 ! figs4 #bb & #bc1 :i* are copi$ f photographs4 ,! facts we h describ$ all po9t to ! conclusion t ! pres5ce ( l>ge quantities ( wat] imprison$ 9 a mass ( lava contributes greatly to its mobility4 ,& ?is conclusion is support$ by s _m o!r consid]ations t x is n[ v g5]ally accept$ by geologi/s4 ,! condition ( ?is imprison$ wat] 9 lavas is "o :i* dem&s fur!r inve/igation at ! h&s ( physici/s4 ,x has be5 sugge/$1 ) "s %[ ( reason1 t ! wat] may exi/ 9 ! mid/ ( ! r$-hot lava z m9ute p>ticles 9 ! curi\s 'sph]oidal condition' ( ,b\tigny1 & t ^! fla% into /eam z ! lava fl[s along4 ,lava1 :5 extrud$ f a volcanic crat] 9 a m or less completely fluid /ate1 fl[s d[n ! side ( ! cone1 & !n f9ds its way along any *annel or valley t may lie 9 its c\rse1 obey+ 9 its movem5ts all ! laws ( fluid bodies4 ,! lava-curr5ts ?us =m$ are sometimes ( enorm\s dim5sions1 & may flood ! :ole c\ntry = _m miles ar\nd ! v5t4 ,lava-/reams h be5 describ$1 :i* h fl[$ = a di/ance ( f fifty to a hundr$ miles f _! s\rce1 & :i* h _h a bread? v>y+ f t5 to tw5ty miles4 ,"s lava-/reams h a ?ickness ( #ejj feet1 or ev5 m4 ,^! measures w give "s idea ( ! enorm\s quantities ( mat]ial br\ght f ! e>?'s int]ior by volcanic action & di/ribut$ ov] its surface4 ,! mass ( lava :i* fl[$ out dur+ an eruption (f ,reykjanes 9 ,icel&1 9 ! ye> #aghc1 has be5 calculat$ to be equal 9 bulk to ,mont ,blanc4 ,!re are _m p>ts ( ! e>?'s surface1 su* z ! ,we/]n ,isles ( ,scotl& & ! ,nor?-ea/ ( ,irel&1 ! ,deccan ( ,india1 & l>ge tracts 9 ! ,rocky ,m\nta9s1 :]e successive lava-%eets h be5 pil$ ^u "o ano!r to ! height ( sev]al ?\s&s ( feet1 & cov] areas ( _m hundr$s or ev5 ?\s&s ( squ>e miles4 ,sid5ote3 ,,features ,,( ,,lava-,,/reams4 ,! m fusible basic lavas are z a g5]al rule m liquid 9 "* ?an any o!rs1 & x is ^! v liquid lavas t are usually f\nd =m+ plateaux built up ( successive lava-/reams4 ,! less liquid lavas1 l ^? ( ,hung>y & ,bohemia1 are n usually f\nd fl[+ to su* di/ances f ! v5t1 b =m dome-%ap$ m\nta9-masses4 ,lava-/reams usually exhibit 9 _! upp] & "u surfaces a scoriace\s texture due to ! escape ( /eam f ! upp] surface1 portions ( ! c9d]y masses s =m$ fall+ (f f ! end ( ! /ream1 & be+ roll$ ov] by ! /ream s z to =m its base4 ,! ?ickness ( ?is scoriace\s upp] & l[] "p ( a lava-/ream v>ies accord+ to ! quantity ( /eam imprison$ 9 x2 b all ?ick lava-/reams h a compact c5tral portion :i* is compos$ ( h>d1 solid rock4 ,v good examples ( ! int]nal /ructure ( lava-/reams may sometimes be exam9$ 9 ! sea-cliffs ( volcanic isl&s4 ,9 fig4 #bg we h giv5 a copy ( a draw+ made :ile sail+ r\nd ! %ores ( ,vulcano4 ,! scoriace\s portions ( lava-/reams are sometimes employ$1 z at ,volvic 9 ! ,auv]gne1 z a build+ mat]ial1 or z at ,neid]m5dig 9 ! ,eifel & 9 ,hung>y = mill-/ones2 ! compact portions are employ$ = build+ & pav+1 & = road metal4 ,! rock ( "s ( ! mod]n lava-/reams ( ,vesuvius is l>gely qu>ri$ = pav+ ! /reets ( ,naples4 ,?is solid portion ( ! lava-/reams 9 sl[ly cool+ d[n f its highly-heat$ condition und]goes contraction1 & 9 consequ5ce is r5t asund] by a numb] ( cracks4 ,sometimes ^! cracks assume a wond]fully regul> arrangem5t1 & ! rock may be brok5 up into v symmetrical masses4 ,illu/ration3 ,fig4 #bg4--,natural section ( a ,lava-/ream 9 ! ,isl& ( ,vulcano1 %[+ ! compact c5tral portion & ! scoriace\s upp] & "u surfaces4 ,sid5ote3 ,,column> ,,/ructure ,,( ,,lavas4 ,if we imag9e a great %eet ( heat$ mat]ial1 l a lava-/ream1 sl[ly cool+ d[n1 x is evid5t t ! contraction :i* mu/ take place 9 x w t5d to produce fissures break+ up ! mass into prisms4 ,a little consid]ation w conv9ce u :at ! =m ( ^! prisms mu/ be4 ,!re are only ?ree regul> figures into :i* a surface c be divid$1 namely1 equilat]al triangles1 squ>es1 & regul> hexagons2 ! fir/ be+ produc$ by ! int]section ( sets ( six l9es radiat+ at angles ( #fj f c]ta9 c5tres2 ! second by ! int]section ( sets ( f\r l9es radiat+ f c5tres at angles ( #ij2 & ! ?ird f sets ( ?ree l9es radiat+ f c5tres at an angle ( #abj4 ,x is evid5t t a less am\nt ( contractile =ce w be requir$ to produce ! sets ( ?ree cracks r ?an ^? ( f\r or six cracks2 or1 9 o!r words1 ! contractile =ce 9 a mass w be compet5t to produce ! cracks :i* give rise to hexagons r ?an ^? :i* =m squ>es or triangles4 ,?is is no d\bt ! reason :y ! prisms =m$ by ! cool+ ( lava1 z well z ^? produc$ dur+ ! dry+ ( />* or clay1 are hexagonal 9 =m4 ,! hexagonal prisms or columns =m$ by contraction dur+ ! consolidation ( lavas v>y greatly 9 size1 accord+ to ! rate ( cool+1 ! nature ( ! mat]ials1 & ! conditions affect+ ! mass4 ,sometimes su* columns may be f\nd hav+ a diamet] ( eight or t5 feet & a l5g? ( five hundr$ feet1 z 9 ! ,%iant ,isles ly+ to ! nor? ( ! ,isl& ( ,skye2 9 o!r cases1 z 9 c]ta9 volcanic glasses1 m9ute columns1 an in* or two 9 l5g? & sc>cely ?ick] ?an a ne$le1 are =m$2 & examples ( almo/ e int]m$iate grade betwe5 ^! two extremes may sometimes be f\nd4 ,! l>ge/ columns are ^? :i* are =m$ 9 v sl[ly cool+ masses4 ,! column> /ructure is exhibit$ by all k9ds ( lava1 & inde$ 9 o!r rock-masses :i* h be5 heat$ by contact ) igne\s masses & gradually cool$4 ,! rocks :i* display ! /ructure 9 greate/ p]fection1 h[ev]1 are ! basalts4 ,mr4 ,scrope fir/ call$ att5tion to ! fact t ! upp] & l[] portions ( lava-/reams sometimes cool 9 v diff]5t ways1 & h5ce produce columns ( dissimil> "*4 ,! l[] portion ( ! mass p>ts ) its heat v sl[ly1 by conduction to ! und]ly+ rocks1 :ile ! upp] portions radiate heat m irregul>ly into ! surr\nd+ atmosph]e4 ,h5ce we (t5 f9d ! l[] portions ( ?ick lava-/reams to be =m$ ( /\t1 v]tical columns ( great regul>ity2 :ile ! upp] "p is made up ( small] & less regul> columns1 z %[n 9 fig4 #bh4 ,illu/ration3 ,fig4 #bh4--,section ( a ,lava-/ream expos$ on ! side ( ! riv] ,ard*e1 9 ! s\?-we/ ( ,france4 ,! rem>kable grotto kn[n z ,f+al's ,cave 9 ! ,isl& ( ,/affa has be5 =m$ 9 ! mid/ ( a lava-/ream su* z we h be5 describ+2 ! ?ick v]tical columns1 :i* rise f b5ea? ! level ( ! sea1 are divid$ by jo9ts & h be5 brok5 away by ! action ( ! sea2 9 ?is way a great cav]n has be5 produc$1 ! sides ( :i* are =m$ by v]tical columns1 :ile ! ro( is made up ( small] & int]lac+ ones4 ,! :ole /ructure be>s "s resemblance to a ,go?ic ca!dral2 ! sea f9d+ access to its floor ( brok5 columns1 & p]mitt+ ! entrance ( a boat dur+ f9e wea!r4 ,simil>1 ?\gh p]haps less /rik+1 /ructures are f\nd 9 _m o!r p>ts ( ! globe :]ev] basaltic & o!r lava-/reams exhibit ! rem>kable column> /ructure z ! result ( _! sl[ cool+4 ,portions ( basaltic columns are (t5 employ$ = po/s by ! road-sides1 z 9 ,c5tral ,g]many & ,bohemia1 or = pav+ /ones1 z 9 ,pompeii & at ! ,monte ,albano ne> ,rome4 ,illu/ration3 ,fig4 #bi4--,portion ( a ,basaltic ,column f ! ,giant's ,causeway1 exhibit+ bo? ! ball-&-socket & ! t5on-&-mortise /ructures4 ,sid5ote3 ,,o!r ,,jo9t-,,/ructures ,,9 ,,lavas4 ,occasionally basaltic lava-/reams exhibit o!r curi\s /ructures 9 addition to ! column>4 ,?us "s basaltic columns are f\nd divid$ into regul> jo9ts by equidi/ant1 curv$ surfaces1 ! jo9ts ?us fitt+ into "o ano!r by a k9d ( ball-&-socket arrangem5t4 ,sometimes we f9d processes project+ f ! angles ( ! curv$ jo9t-surfaces1 :i* cause ! blocks to fit toge!r z ) a t5on & mortise4 ,?is k9d ( /ructure is admirably display$ at ! ,giant's ,causeway1 ,co4 ,antrim1 9 ! ,nor? ( ,irel&4 ,a portion ( a basaltic column f ?is locality is repres5t$ 9 fig4 #bi4 ,illu/ration3 ,fig4 #cj4--,ve9 ( gre5 ,pit*/one1 at ,*iaja di ,luna 9 ! ,isl& ( ,ponza1 break+ up into regul> columns1 & into sph]ical masses ) a conc5tric s]ies ( jo9ts4 ,:ile ! ord9>y column> /ructures are v common 9 basalts1 ! ball-&-socket & t5on-&-mortise /ructures are exce$+ly r>e4 ,! "q ( ! mode ( orig9 ( ^! rem>kable /ructures has giv5 rise to mu* discussion1 & ! op9ions ( geologi/s & physici/s are by no means unanim\s ^u ! subject4 ,sometimes we f9d masses ( lava trav]s$ by curv$ jo9ts1 & occasionally we f9d curi\s comb9ations ( curv$ & plane jo9ts1 giv+ rise to appe>ances sc>cely less rem>kable ?an ^? pres5t$ by ! columns ( ! ,giant's ,causeway4 ,"s ( ! m /rik+ examples ( ?is k9d h be5 describ$ & expla9$ by ,pr(essor ,bonney4 ,illu/ration3 ,fig4 #ca4--;,illu/ration ( ! ',p]litic /ructure' 9 glassy ,rocks4 a4 ,p]lltic /ructure1 z se5 9 a lava f ,hung>y4 b4 ,! same /ructure1 artificially produc$ 9 ,canada ,balsam dur+ cool+4 ,sid5ote3 ,,p]litic-,,/ructure ,,9 ,,lavas4 ,9 ! ,ponza ,isl&s !re occurs a rem>kable example ( a column> pit*/one1 :i* is also trav]s$ by a memb] ( curv$ conc5tric jo9ts1 caus+ ! rock to break up into pieces l ! coats ( an onion4 ,?is rem>kable rock-mass is repres5t$ 9 fig4 #cj4 ,a v simil> /ructure is (t5 se5 9 c]ta9 glassy lavas1 :5 !y are exam9$ 9 ?9 sections "u ! microscope4 ,su* glassy lavas exhibit ! peculi> lu/re ( "m-(-pe>ly d\btless 9 consequ5ce ( ! int]f]5ce ( light along ! cracks4 ,lavas exhibit+ ?is "* are kn[n to geologi/s z 'p]lites4' ,! p]litic /ructure has be5 produc$ artificially by ,mr4 ,gr5ville ,cole 9 ,canada ,balsam1 & by ,,mm4 ,fonqu & ,mi*el ,lvy1 9 *emically deposit$ silica4 ,see fig4 #ca4 ,a ?ick lava-/ream mu/ take an enorm\s p]iod to cool d[n--probably _m hundr$s or ev5 ?\s&s ( ye>s4 ,x is possible to walk ov] lava-/reams 9 :i* at a few in*es bel[ ! surface ! rock is /ill r$-hot1 s t a piece ( /ick is light$ if ?ru/ into a crack4 ,lava is a v bad conductor ( heat1 & loose scori & du/ are /ill worse conductors4 ,dur+ ! eruption ( ,vesuvius 9 #ahgb1 masses ( sn[ :i* 7 cov]$ ) a ?ick lay] ( scori1 & aft]w>ds by a /ream ( lava1 7 f\nd ?ree ye>s aft]w>ds consolidat$ into ice1 b n melt$4 ,! city ( ,catania is con/antly suppli$ ) ice f masses ( sn[ :i* h be5 buri$ "u ! ejections ( ,etna4 ,dur+ ! cool+ d[n ( lavas1 ! escape ( /eam & v>i\s gases gives rise to ! deposition ( _m beautiful cry/all9e sub/ances 9 ! cavities & on ! surfaces ( ! lava4 ,deposits ( sulphur1 specul>-iron1 tridymite1 & _m o!r sub/ances are (t5 ?us produc$1 & ! col\r & appe>ance ( ! rock-masses are sometimes completely disguis$ by ^! surface incru/ations1 or by ! decomposition ( ! mat]ials ( ! lava by ! action ( ! add gases1 & vap\rs ^u x4 ,sid5ote3 ,,s9k+ ,,( ,,surfaces ,,( ,,lava-,,/reams4 ,v frequ5tly ! surface ( a lava-/ream becomes solid1 :ile ! deep] portions reta9 _! fluid condition2 "u su* circum/ances ! c5tral portions may fl[ away1 leav+ a great holl[ *amb] or cav]n4 ,9 consequ5ce ( ?is action1 we n unfrequ5tly f9d ! upp] surface ( a lava-curr5t exhibit+ a depression1 due to ! fall+ 9 ( ! solidifi$ upp] portions :5 ! liquid lava has fl[$ away & left x unsupport$1 z 9 fig4 #cb4 ,illu/ration3 ,fig4 #cb4--,transv]se section ( a ,lava /ream4 7,! dott$ l9e indicates ! orig9al surface47 ,,*apt] ,v ,,! ,,int]nal ,,/ructure ,,( ,,volcanic ,,m\nta9s4 ,ne> ! high-road :i* passes betwe5 ! t[ns ( ,eg] & ,franz5bad 9 ,bohemia1 !re rises a small hill kn[n z ! ,kamm]bhl 7see fig4 #cc71 :i* has attract$ to itself an am\nt ( int]e/ & att5tion q out ( proportion to its magnitude or importance4 ,dur+ ! latt] "p ( ! la/ c5tury & ! e>li] ye>s ( ! pres5t "o1 ! fi]ce/ controv]sies 7 wag$ betwe5 ! p>tisans ( rival s*ools ( cosmogony ov] ?is insignificant hill2 "s ma9ta9+ t x orig9at$ 9 ! combu/ion ( a b$ ( coal1 o!rs t its mat]ials 7 entirely =m$ by "s k9d ( 'aque\s precipitation1' & o!rs aga9 t ! hill 0 ! relic ( a small volcanic cone4 ,among ^? :o took a v active "p 9 ?is controv]sy 0 ! poet ,goe!1 :o /\tly ma9ta9$ ! volcanic orig9 ( ! ,kamm]bhl1 /yl+ x 'a pocket edition ( a volcano4' ,to ,goe! belongs ! m]it ( hav+ sugge/$ a ,v simple me?od by :i* ! controv]sies conc]n+ ?is hill might be set at re/3 he propos$ t a s]ies ( excavations %\ld be und]tak5 ar\nd ! hill1 & a tunnel driv5 "r "u its c5tre4 ,illu/ration3 ,fig4 #cc4--,! ,kamm]bhl ( ,kamm]b]g1 ,bohemia4 7,z se5 f ! s\?-we/7 ,sid5ote3 ,,! ,,kamm]b,,hl4 ,! poet's fri5d1 ,c\nt ,casp> von ,/]nb]g1 det]m9$ to put ?is project into execution4 ,?is s]ies ( excavations1 :i* 0 complet$ 9 #ahcg1 has = ev] set at re/ all d\bts z to ! volcanic orig9 ( ! ,kamm]bhl4 ,a plug ( basalt 0 f\nd fill+ ! c5tre ( ! mass1 & connect$ ) a small lava-/ream fl[+ d[n ! side ( ! hill2 :ile ! bulk ( ! hill 0 %[n to be compos$ ( volcanic scori & lapilli4 ,! section fig4 #cd w illu/rate ! /ructure ( ! hill z reveal$ by ^! int]e/+ excavations4 ,illu/ration3 ,fig4 #cd4--,section ( ! ,kamm]bhl1 9 ,bohemia4 a a4 ,metamorphic rocks4 b4 ,basaltic scori4 c4 ,solid plug ( basalt ris+ ?r\gh ! c5tre ( ! volcanic pile1 d d4 ,lava-/ream compos$ ( ! same rock4 e e4 ,alluvial matt] surr\nd+ ! old volcano4 7,! dott$ l9es indicate ! probable =m] outl9e ( ! volcano47 ,sid5ote3 ,,volcanoes ,,dissect$ ,,by ,,d5udation4 ,x c ( c\rse v seldom happ5 t actual m9+ op]ations1 l ^? und]tak5 9 ! case ( ! ,kamm]bhl1 w be resort$ to 9 ord] to det]m9e ! /ructure ( volcanic m\nta9s4 ,geologi/s h usually to avail !mselves ( less direct1 b by no means less c]ta91 me?ods ?an t ( mak+ artificial excavations 9 ord] to inve/igate ! e>?'s cru/4 ,=tunately x happ5s t :at we _c accompli% ourselves1 nature does = u4 ,! action :i* we call 'd5udation' s]ves z a scalpel to dissect volcanic m\nta9s = u1 & to expose _! inn] recesses to our view4 ,_m portions ( ! e>?'s surface are complete museums cr[d$ ) volcanic 'subjects1' exhibit+ e /age ( ! process ( dissection4 ,9 "s1 ra9s & w9ds h /ripp$ (f ! loose cov]+ ( c9d]s & du/1 & expos$ ! h>d] & m solid p>ts--! skeleton ( ! m\nta94 ,9 o!rs1 ! "w ( de/ruction has proce$$ /ill fur!r1 & sl[ly we>+ riv]s or ! waves ( ! sea may h cut p]fect1 v]tical sections ( ! m\nta9-mass4 ,sometimes ! removal ( ! mat]ials ( ! volcanic m\nta9 has gone on to su* an ext5t t its base & gr\nd-plan are fully expos$4 ,x only requires ! necess>y skill 9 piec+ toge!r our obs]vations on ^! dissect$ volcanoes1 9 ord] to arrive at j views conc]n+ ! 'comp>ative anatomy' ( volcanoes4 ,z ! k ( ! /ructure ( animals rema9$ 9 ! mo/ rudim5t>y condition until ! practice ( dissection 0 comm5c$1 s our k ( volcanoes 0 likewise exce$+ly imp]fect till geologi/s avail$ !mselves ( ! opportunities af=d$ to !m ( /udy+ naturally dissect$ volcanic m\nta9s4 ,9 "s cases we may f9d t ! sea has encroa*$ on ! base ( a volcanic hill1 till "o half ( x has be5 wa%$ away1 & ! /ructure ( ! mass to its v c5tre is expos$ to our view4 ,?us 9 fig4 #f 7page #dc71 x w be se5 t !re lies 9 front ( ,vulcano a p59sula call$ ,vulcanello1 consi/+ ( ?ree volcanic cones1 unit$ at _! base1 ) ! lava-/reams :i* h fl[$ f !m4 ,"o half ( ! cone on ! left-h& side ( ! picture has be5 completely wa%$ away by ! sea1 & a p]fect section ( ! int]nal /ructure ( ! cone is expos$4 ,! appe>ances pres5t$ 9 ?is section are %[n 9 ! sket*1 fig4 #ce4 ,"s portions ( ! face ( ?is section are conceal$ by ! heaps ( fragm5ts :i* h fall5 f x1 b en\gh is visible to conv9ce u t ?ree k9ds ( /ructures g to make up ! cone4 ,9 ! fir/ place1 we h ! loose scori & lapilli1 :i* 9 fall+ ?r\gh ! air h arrang$ !mselves 9 tol]ably regul> lay]s ^u ! sides ( ! cone4 ,illu/ration3 ,fig4 #ce4--,natural section or a ,volcanic ,cone 9 ! ,isl& ( ,vulcano4 a4 ,crat]4 b b4 ,lava-/reams4 c4 ,dykes :i* h cle>ly =m$ ! ducts1 ?r\gh :i* ! lava has ris5 to ! crat]4 d d4 ,/ratifi$ volcanic scori4 e4 ,talus ( fall5 mat]ials4 ,9 ! second place1 we h lava-/reams :i* h be5 eject$ f ! crat] or f fissures on ! flanks ( ! cone1 & fl[$ d[n its sides4 ,& ?irdly1 we f9d masses ( lava fill+ up cracks 9 ! cone2 ^! latt] are call$ 'dykes4' ,( ^! ?ree k9ds ( /ructures mo/ volcanic m\nta9s are built up1 b 9 diff]5t cases ! "p play$ by ^! sev]al elem5ts may be v unequal4 ,sometimes volcanoes consi/ entirely ( fragm5t>y mat]ials1 at o!rs !y are made up ( lavas only1 :ile 9 ! majority ( cases !y h be5 =m$ by alt]nations ( fragm5t>y & fluid ejections1 ! :ole be+ b\nd toge!r by dykes1 :i* are masses ( lava inject$ into ! cracks =m$ f "t to "t 9 ! sides ( ! gr[+ cone4 ,if we direct our att5tion 9 ! fir/ place to ! fragm5t>y ejections1 we %all f9d t !y affect a v m>k$ & peculi> arrangem5t1 :i* is be/ exhibit$ 9 ^? volcanic cones compos$ entirely ( su* mat]ials4 ,sid5ote3 ,,int]nal ,,/ructure ,,( ,,volcanic ,,cones4 ,ev]yone :o exam9es volcanoes = ! fir/ "t w probably be /ruck by ! regul> /ratification ( mat]ials ( :i* !y are compos$4 ,?us ! tuffs cov]+ ! city ( ,pompeii are f\nd to consi/ ( num]\s ?9 lay]s ( lapilli & volcanic du/1 p]fectly di/9ct f "o ano!r1 & assum+ ev5 ! arrangem5t :i* we usually reg>d z *>act]i/ic ( mat]ials t h be5 deposit$ f a /ate ( susp5sion 9 wat]4 ,! fragm5t>y mat]ials 9 fall+ ?r\gh ! air are sort$1 ! f9] p>ticles be+ c>ri$ f>!r f ! v5t ?an ! l>g] & heavi] ones4 ,! =ce ( diff]5t volcanic outbur/s also v>ies greatly1 & sometimes mat]ials ( diff]5t "* are ?r[n out dur+ successive ejections4 ,^! facts w be illu/rat$ by fig4 #cf1 :i* is a draw+ ( a section expos$ 9 a qu>ry op5$ 9 ! side ( ! ,kamm]bhl4 ,9 ?is section we see t ! fall+ scori h be5 arrang$ 9 rudely p>allel b$s1 b ! regul> deposition ( ^! has be5 int]rupt$ by ! ejection ( masses ( burnt slate torn f ! side ( ! v5t1 probably dur+ "s m ?an usually viol5t p>oxysm ( ! volcano4 ,9 ^? volcanoes :i* are built up ( tuffs & mat]ials :i* h fall5 9 ! condition ( a muddy pa/e1 ! p]fect /ratification ( ! mass is (t5 v /rik+ inde$1 & l>ge cones are f\nd built up ( ?9 uni=mly-spread lay]s ( m or less f9ely-divid$ mat]ials1 dispos$ 9 p>allel succession4 ,su* f9ely-/ratifi$ tuff-cones ab\nd 9 ! di/rict ( ! ,campi ,phlegri4 ,illu/ration3 ,fig4 #cf4--,section 9 ! side ( ! ,kamm]bhl1 ,bohemia4 a a4 /ratifi$ basaltic scori4 b b4 ,b&s made up ( fragm5ts ( burnt slate4 c4 ,/ratifi$ basaltic scori4 d d4 ,pseudo-dykes occupy+ l9es ( fault4 ,sid5ote3 ,,arrangem5t ,,( ,,fragm5tal ,,mat]ials4 ,if1 9 consequ5ce ( any subt]ranean movem5ts1 fissures are produc$ 9 ! sides ( ! cones =m$ ( fragm5t>y mat]ials1 ^! (t5 become gradually fill$ ) loose fragm5ts f ! sides ( ! fissure1 & 9 ?is mann] 'pseudo-dykes' are =m$4 ,an example ( su* pseudo-dykes is repres5t$ 9 fig4 #cf1 :]e ! b$s compos+ ! volcanic cone ( ! ,kamm]bhl are se5 to h be5 brok5 across or fault$1 & ! fissures produc$ 9 ! mass h be5 gradually fill$ ) loose fragm5ts4 ,x is n difficult to imitate1 on a small scale1 ! conditions :i* exi/ at ^? volcanic v5ts f :i* only fragm5t>y mat]ials are eject$4 ,if we take a bo>d hav+ a hole 9 its c5tre1 into :i* a pipe is ins]t$ convey+ a /rong air-bla/1 we %all1 by introduc+ "s light mat]ial l bran or sawdu/ into ?is pipe cause an ejection ( fragm5ts1 :i* w1 :5 ! bo>d is plac$ horizontally1 fall ar\nd ! orifice ( ! pipe & accumulate !re 9 a conical heap 7fig4 #cg74 ,x w be f\nd necess>y1 z 0 %[n by ,mr4 ,woodw>d1 :o p]=m$ ! exp]im5t be=e ! ,physical ,society1 to adopt "s contrivance1 su* z a screw1 = =c+ ! mat]ial into ! air-pipe4 ,if we alt]nately introduce mat]ials ( diff]5t col\rs1 l mahogany- & deal-sawdu/ into ! pipe1 ^! mat]ials w be arrang$ 9 lay]s :i* c be easily recognis$1 & ! mode ( accumulation ( ! mass w be evid5t4 ,by means ( a %eet ( t9 or c>dbo>d we may divide ?is m9iature volcanic cone v]tically into two portions1 & if we sweep "o ( ^! away ! int]nal /ructure ( ! o!r half w be cle>ly display$ be=e our eyes4 ,9 ?is way we %all f9d t ! conical heap ( sawdu/ ) ! hole 9 its c5tre has a v peculi> & def9ite arrangem5t ( its mat]ials4 ,x is made up ( a numb] ( lay]s ea* ( :i* slopes 9 opposite directions1 t[>ds ! c5tre ( ejection & away f t c5tre4 ,^! lay]s are ?icke/ along ! l9e ( ! circle :]e ! *ange 9 slope takes place1 & !y ?9 away 9 ! direction ( ! two opposite slopes4 ,illu/ration3 ,fig4 #cg4--;,exp]im5tal illu/ration ( ! mode ( ,=mation ( ,volcanic ,cones compos$ ( fragm5tal mat]ials4 ,sid5ote3 ,,cause ,,( ,,?is ,,arrangem5t4 ,! cause ( ?is peculi> arrangem5t ( ! mat]ials is evid5t4 ,! sawdu/ ?r[n up by ! air bla/ desc5ds 9 a %[] & t5ds to accumulate 9 a circul> heap ar\nd ! orifice1 ! area ( ?is circul> heap be+ det]m9$ by ! =ce ( ! bla/4 ,)9 ?is circul> area1 h[ev]1 ! quantity ( fall+ fragm5ts is n ev]y:]e ! same2 along a circle surr\nd+ ! v5t at a c]ta9 di/ance1 ! maximum numb] ( fall+ fragm5ts w be f\nd to desc5d1 & "h ! ?icke/ deposit w take place4 ,z ?is goes on1 a circul> ridge w be =m$1 ) slopes t[>ds & away f ! c5tre ( injection4 ,z ! ridge increases 9 height1 ! mat]ials w t5d to roll d[n ei!r "o slope or ! o!r1 & gradually a /ructure ( ! =m %[n 9 ! figure w be pil$ up4 ,! mat]ials slid+ d[n ! out] slope w t5d to increase ! area ( ! base ( ! cone1 :ile ^? :i* f9d _! way d[n ! inn] slope w fall into ! v5t to be aga9 eject$4 ,illu/ration3 ,fig4 #ch4--,natural section ( a ,tuff-cone =m+ ! ,cape ( ,mis5um1 & exhibit+ ! peculi> int]nal ,arrangem5t *>act]i/ic ( volcanoes compos$ ( fragm5t>y mat]ials4 ,volcanic cones compos$ ( scori1 du/1 c4 are f\nd to h exactly ! same int]nal /ructure z is exhibit$ by ! m9iature cone ( sawdu/4 ,! m or less regul> lay]s ( :i* !y are made up dip 9 opposite directions1 away f & t[>ds ! v5t1 & ?9 out 9 ! direction ( _! dip 7see fig4 #ch74 ,9 small cones ! crat] or c5tral cavity is ( consid]able size 9 proportion to ! :ole mass1 b z ! cone gr[s upw>ds & outw>ds1 ! dim5sions ( ! crat] rema9 ! same1 :ile ! area ( ! base & ! height ( ! cone are cont9ually increas+4 ,?is is ! normal /ructure ( volcanic cones =m$ ( fragm5t>y mat]ials1 ?\gh1 z we %all h]eaft] %[1 _m irregul>ities are (t5 produc$ by local & tempor>y causes4 ,illu/ration3 ,fig4 #ci4--,section ( a small ,scoria-cone =m$ )9 ! crat] ( ,vesuvius 9 ! ye> #ahhe1 illu/rat+ ! fill+-up ( ! c5tral t5t ( ! cone by subsequ5t ejections4 ,9 "s cases ! c5tral v5t ( a volcanic scoria-cone may be fill$ up by subsequ5t ejections4 ,a beautiful example ( ?is k9d 0 obs]v$ by ,abi*1 9 ! case ( a small cone =m$ )9 ! crat] ( ,vesuvius 9 #ahce1 & is repres5t$ 9 fig4 #ci4 ,illu/ration3 ,fig4 #dj4--,volcanic ,cones compos$ ( ,scori1 & brea*$ on "o side by ! outfl[ ( lava-curr5ts4 ,sid5ote3 ,,brea*$ ,,cones4 ,_m cones =m$ 9 ! fir/ in/ance ( scori1 tuff1 & pumice may give rise to /reams ( lava1 be=e ! v5t :i* !y surr\nd s9ks into a /ate ( quiesc5ce4 ,9 ^! cases1 ! liquid lava 9 ! v5t gives (f su* quantities ( /eam t masses ( fro? or scori are =m$1 :i* are eject$ & accumulate ar\nd ! orifice4 ,:5 ! =ce ( ! explosive action is exhau/$1 ! lava rises bodily 9 ! crat]1 :i* x m or less completely fills4 ,b1 ev5tually1 ! weak] side ( ! crat]-wall yields b5ea? ! pressure ( ! liquid mass1 & ?is "p ( ! crat] & cone is swept away be=e ! advanc+ lava-/ream4 ,examples ( su* 'brea*$ cones' ab\nd 9 ,auv]gne & _m o!r volcanic di/ricts 7see fig4 #dj74 ,a beautiful example ( a cone =m$ ( pumice1 :i* has be5 brea*$ by ! outfl[ ( a lava-/ream ( obsidian1 occurs 9 ! ,lip>i ,isl&s1 at ! ,roc*e ,rosse4 ,x is ?is locality :i* supplies ! :ole _w ) pumice 7see fig4 #da74 ,illu/ration3 ,fig4 #da4--;,campo ,bianco1 9 ! ,isl& ( ,lip>i4 ,a ,pumice-cone brea*$ by ! ,outfl[ ( an ,obsidian ,lava-curr5t4 ,x is (t5 surpris+ to f9d h[ volcanic cones compos$ ( loose mat]ials1 su* z tuffs1 scori1 or pumice1 reta9 _! di/9ctive =ms1 & ev5 ! %>pness ( _! outl9es1 dur+ enorm\s p]iods ( "t4 ,?us1 9 ! scoria-cones :i* ab\nd 9 ! ,auv]gne1 & 71 9 all probability1 =m$ be=e ! hi/orical p]iod1 ! %>p edges ( ! crat]s appe> to h suff]$ sc>cely any erosion1 & ! cones are z p]fect 9 _! outl9es z ?\gh =m$ b ye/]day4 ,x is probable t ! facility ) :i* ^! c9d]y heaps are p5etrat$ by ! ra9 :i* falls ^u !m is ! cause :y !y are n m frequ5tly wa%$ away4 ,illu/ration3 ,fig4 #db4--,volcanic ,cones 9 ,auv]gne :i* h suff]$ to "s ext5t f atmosph]ic d5udation4 ,sometimes1 h[ev]1 scoria-cones are f\nd r$uc$ by atmosph]ic wa/e to m]e heaps ( c9d]s1 9 :i* ! position ( ! crat] is indicat$ only by a slight depression1 z 9 fig4 #db4 ,sid5ote3 ,,cones ,,compos$ ,,( ,,lava4 ,:5 b little explosive action takes place at ! volcanic v5t1 & only fluid lava is eject$1 m\nta9s are =m$ diff]+ v greatly 9 "* f ! cones compos$ ( fragm5t>y mat]ials4 ,if ! lavas be ( v p]fect liquidity1 l ^? erupt$ 9 ! ,s&wi* ,isl&s1 !y fl[ outw>ds ar\nd ! v5t to enorm\s di/ances4 ,by ! accumulation ( mat]ials dur+ successive outbur/s1 a conical mass is built up :i* has b a slight elevation 9 proportion to ! area ( its base4 ,?us 9 ,hawaii we f9d great volcanic cones1 compos$ ( v fluid lavas1 :i* h a height ( ne>ly #ad1jjj feet ) a diamet] ( base ( sev5ty miles4 ,9 ^! ,hawaiian m\nta9s ! slope ( ! sides r>ely exce$s #f to #h4 ,b if1 on ! o!r h&1 ! lavas be ( mu* m viscid consi/5cy1 ! "* ( ! volcanic cones :i* are produc$ by _! extrusion w be v diff]5t4 ,! outwell+ mat]ial w t5d to accumulate & heap itself up ar\nd ! v5t4 ,by successive ejections ! fir/-=m$ %ell is =c$ upw>ds & outw>ds1 & a /eep-sid$ protub]ant mass is =m$1 exhibit+ 9 its int]ior a m>k$ conc5tric arrangem5t4 ,dr4 ,ed4 ,rey]1 ( ,grtz1 has devis$ a v +5i\s me?od = reproduc+ on a m9iature scale ! *>act]i/ic features ( ^! eruptions ( viscid lavas4 ,he takes a quantity ( pla/] ( ,p>is r$uc$ to a pa/y consi/5ce1 :i* he =ces ?r\gh a hole 9 a bo>d4 ,! pla/] accumulates 9 a great r\nd$ boss ab\t ! orifice ?r\gh :i* x has be5 =c$4 ,if ! pla/] h "s col\r+ matt] introduc$ into x1 ! mass1 on be+ cut across1 w exhibit 9 ! disposition ( its col\r-b&s ! k9d ( action :i* has gone on dur+ its extrusion1 fig4 #dc4 ,illu/ration3 ,fig4 #dc4--;,exp]im5tal illu/ration ( ! ,mode ( ,=mation ( volcanic cones compos$ ( viscid lavas4 ,illu/ration3 ,fig4 #dd4--,! ,gr& ,puy ( ,s>c\i1 compos$ ( tra*yte1 ris+ betwe5 two brea*$ scoria-cones 7,auv]gne74 ,!re are _m volcanic cones :i* exhibit cle> evid5ce ( hav+ ?us be5 =m$ by ! extrusion ( a viscid mass ( lava ?r\gh a volcanic fissure4 ,among su* we may m5tion ! domitic ,puys ( ,auv]gne1 fig4 #dd1 _m &esitic volcanoes 9 ,hung>y1 ! phonolite hills ( ,bohemia1 & ! s-call$ 'mamelons' ( ! ,isl& ( ,b\rbon4 ,see figs4 #de & #df4 ,:5 ! int]ior ( ^! masses is expos$ by natural or artificial sections1 !y are all f\nd to exhibit ! onion-l /ructure :i* occurs 9 ! pla/] models4 ,sid5ote3 ,,int]nal ,,/ructure ,,( ,,lava-,,cones4 ,illu/ration3 ,fig4 #de4--,volcanic ,cone 7,mamelon7 compos$ ( v viscid lava4 7,isl& ( ,b\rbon47 ,illu/ration3 ,fig4 #df4--;,ano!r ,mamelon 9 ! ,isl& ( ,b\rbon1 ) a crat] at its summit4 ,b :ile "s volcanoes are compos$ entirely ( ! fragm5t>y ejections & o!rs are :olly =m$ by successive outfl[s ( lava1 ! majority ( volcanoes1 especially ^? ( l>g] dim5sions1 are built up ( alt]nations ( ^! diff]5t k9ds ( mat]ials4 ,illu/ration3 ,fig4 #dg4--;,cliff-section 9 ! ,isl& ( ,madeira1 %[+ h[ a composite volcano is built up ( lava-/reams1 b$s ( scori1 & dykes4 ,sid5ote3 ,,natural ,,sections ,,( ,,cones4 ,! /ructure ( ^! composite cones may be und]/ood by an inspection ( ! accompany+ fig4 #dg1 :i* %[s ! appe>ances pres5t$ 9 a cliff on ! coa/ ( ! ,isl& ( ,madeira4 ,we see t ! mass is made up ( num]\s lay]s ( volcanic scori1 alt]nat+ ) %eets ( lava4 ,! latt]1 :i* are repres5t$ 9 transv]se section 9 ! draw+1 are se5 to ?9 out on ei!r side1 & to v>y greatly 9 bread?4 ,besides ! alt]nat+ masses ( scori & ! lava-%eets1 !re are se5 9 ! section1 b&s ( a bright-r$ col\r1 :i* are repres5t$ 9 ! draw+ by black l9es4 ,^! are lay]s ( soil1 or volcanic du/1 :i*1 by ! passage ( a lava-/ream ov] _! surface1 h be5 burnt s z to acquire a brick-r$ col\r4 ,^! b&s ( r$ mat]ial1 to :i* ! "n ( 'lat]ite' has be5 frequ5tly appli$1 v commonly occur 9 sections ( composite volcanic cones4 ,cross+ ! :ole ( ! horizontally-dispos$ masses 9 ! section1 we f9d a numb] ( 'dykes1' :i* are evid5tly great cracks fill$ ) lava f bel[4 ,"s ( ^! run v]tically ?r\gh ! cliffs1 o!rs obliquely4 ,9 "s cases ! lava1 ris+ to fill a dyke1 has fl[$ z a lava-/ream at ! surface4 ,la/ ( all1 we mu/ call att5tion to ! fact t ! section exhibits evid5ce ( great movem5ts hav+ tak5 place subsequ5tly to ! accumulation ( ! :ole ( ! mat]ials4 ,a great crack has be5 produc$1 on "o side ( :i* ! :ole mass has subsid$ bodily1 giv+ rise to ! ph5om5on :i* geologi/s call a 'fault4' ,9 ! section1 fig4 #bg1 p4 #ajd1 copi$ f a draw+ ( a sea-cliff 9 ! ,isl& ( ,vulcano1 a transv]se section ( a lava-/ream is repres5t$ on a some:at l>g] scale4 ,! upp] & "u surface ( ! lava-/ream is se5 to h a scoriace\s /ructure1 b ! ?ick c5tral mass is compact1 & divid$ by regul> jo9t-planes4 ,?is section also illu/rates ! fact t1 be=e ! lava-/ream fl[$ d[n ! sides ( ! m\nta91 a valley _h be5 cut by meteoric ag5cies on ! flanks ( ! volcano1 ! dykes :i* trav]se ! l[] b$s ( tuff be+ abruptly truncat$4 ,9 m\nta9 rav9es1 ^u ! slopes ( anci5t volcanoes1 & 9 ! cliffs ( volcanic isl&s1 we are (t5 able to /udy ! way 9 :i* ^! great m\nta9 masses are built up ( alt]nat+ lava-curr5ts1 b$s ( volcanic agglom]ate1 scori1 tuff & du/1 & int]sect+ dykes4 ,9 fig4 #dh1 ! features above describ$ are illu/rat$ by a section 9 ! sides ( ! great volcano ( ,mont ,dore4 ,illu/ration3 ,fig4 #dh4--,section se5 at ! cascade4 ,ba9s du ,mont ,dore4 ,illu/ration3 ,fig4 #di4--,section 9 ! ,isl& ( ,v5toti5ne1 %[+ a great /ream ( &esitic lava ov]ly+ /ratifi$ tuffs4 ,sid5ote3 ,,sections ,,9 ,,! ,,ponza ,,isl&s4 ,9 figs4 #di1 #ej1 #ea1 & #eb1 we h giv5 draw+s ( portions ( ! sea-cliffs 9 sev]al ( ! ,ponza ,isl&s1 a small volcanic gr\p (f ! ,italian coa/4 ,illu/ration3 ,fig4 #ej4--;,cliff on ! s\? side ( ! ,isl& ( ,san ,/ephano4 a4 ,tra*yte lava-/ream1 ) a scoriace\s upp] surface ov]laid by /ratifi$ tuffs1 b4 ,illu/ration3 ,fig4 #ea4--,! headl& ( ,monte della ,gu>dia1 9 ! ,isl& ( ,ponza4 a4 ,column> tra*yte4 b4 ,/ratifi$ tuffs4 c4 ,pumice\s agglom]ates4 d4 ,dyke ( rhyolite4 ,illu/ration3 ,fig4 #eb4--,we/]n side ( ! same headl&1 z se5 f ! nor? side ( ,luna ,bay4 a4 ,tra*yte lava4 b4 ,/ratifi$ tuffs4 c4 ,dykes ( rhyolite1 ) _! edges pass+ into pit*/one4 d4 ,pumice\s agglom]ate4 ,illu/ration3 ,fig4 #ec4--,sea-cliff at ,il ,capo1 ! nor?-ea/ po9t ( ,sal9a %[+ /ratifi$ agglom]ates trav]s$ by num]\s dykes1 ! :ole be+ uncon=mably ov]laid by /ratifi$ aque\s deposits4 ,fig1 #ec repres5ts a cliff-section 9 ! isl& ( ,sal9a1 "o ( ! ,lip>is1 exhibit+ evid5ce t a s]ies ( volcanic agglom]ates trav]s$ by dykes ( ,&esite h be5 d5ud$ & cov]$ by a rec5t /ratifi$ deposit4 ,sid5ote3 ,,"p ,,play$ ,,by ,,dykes ,,9 ,,cone-,,build+4 ,9 ! =mation ( ^! great composite cones1 a m9or b by no means insignificant "p is play$ by ! dykes1 or lava-fill$ fissures1 :i* are se5 trav]s+ ! mass 9 all directions4 ,t dyke-fissures (t5 rea* ! surface ( a volcanic cone1 & t ! mat]ial :i* injects !m !n issues z a lava-/ream1 is illu/rat$ by fig4 #ed4 ,! =mation ( ^! cracks 9 a volcanic cone1 & _! injection by liquid lava1 mu/ ( c\rse di/5d ! m\nta9\s mass & increase its volume4 ,if we visit ! great crat]-walls ( ,somma 9 ,vesuvius1 & ( ! ,val del ,bove 9 ,etna1 we %all f9d t ! dykes are s num]\s t !y make up a consid]able portion ( ! mass4 ,:5 ! loose scori & tuffs are remov$ by d5udation1 ^! h>d dykes (t5 /& up prom95tly l great walls1 z repres5t$ 9 fig4 #ee4 ,ev5 9 su* cases z ^!1 h[ev]1 x is d\btful :e!r ! bulk ( all ! dykes put toge!r exce$s "o-t5? ( t ( ! lavas & fragm5t>y mat]ials4 ,illu/ration3 ,fig4 #ed4--,section obs]v$ 9 ! ,val del ,bove1 ,etna1 %[+ a basaltic dyke1 f ! upp] "p ( :i* a lava-curr5t has fl[$4 ,illu/ration3 ,fig4 #ee4--;,basaltic ,dykes project+ f masses ( /ratifi$ scori 9 ! sides ( ! ,val del ,bove1 ,etna4 ,h5ce we are l$ by an exam9ation ( ! int]nal /ructure ( volcanic m\nta9s to conclude t scori- & tuff-cones1 & cones =m$ ( v liquid lavas1 increase by an exog5\s mode ( gr[?1 all new mat]ials be+ add$ to !m f )\t2 9 ! cones =m$ ( v viscid lavas1 on ! o!r h&1 ! gr[? is endog5\s1 tak+ place by successive accretions )9 x4 ,! composite cones owe _! orig9 to bo? ! exog5\s & ! endog5\s modes ( gr[?1 b 9 a mu* great] degree to ! =m] ?an ! latt]4 ,! lay]s ( scori1 tuff1 & du/1 & ! successive lava-/reams are add$ to ! mass f )\t1 & ! lava =m+ ! dykes f )9 x4 ,sid5ote3 ,,!ory ,,( ,,elevation ,,crat]s4 ,!re are d\btless cases 9 :i*1 :5 a tuff-cone is =m$1 a mass ( v viscid lavas is extrud$ into its int]ior1 & ! mass is di/5d$ l a gigantic bubble4 ,b inasmu* z ! v viscid lavas d n appe> to give rise to scori to any?+ l ! same ext5t z ! m liquid k9ds1 su* 'cupolas1' z !y h be5 call$ by "s ,g]man geologi/s1 are probably n v num]\s1 & may be reg>d$ z con/itut+ ! exception r ?an ! rule4 ,! idea :i* 0 =m]ly ent]ta9$ by "s geologi/s t all great volcanic m\nta9s 7 =m$ ( masses orig9ally deposit$ 9 a horizontal position1 & subsequ5tly bl[n up into a conical =m1 has be5 effectually dispos$ ( by ! obs]vations ( ,lyell & ,scrope4 ,! condition ( ! great fluid masses :i* und]lie volcanic v5ts is ano!r po9t on :i* mu* light has be5 ?r[n by ! /udy ( naturally-dissect$ volcanoes4 ,9 "s cases1 z 0 %[n by ,ho*/ett] dur+ 8 admirable rese>*es among ! ,new ,zeal& volcanoes1 ! ris+ lavas =m a great *amb] = !mselves 9 ! mid/ ( a volcanic c9d]-cone1 tak+ ! place ( loose mat]ials :i* are re-eject$ f ! v5t1 or h be5 re-fus$ & absorb$ into ! mass ( lava itself4 ,f ?is c5tral res]voir ( lava1 eruptions are kept up = "s "t1 b :5 ! volcano s9ks into a /ate ( quiesc5ce ! lava sl[ly consolidates4 ,9 su* sl[ly solidifi$ masses ( lava1 v beautiful gr\ps ( radiat+ columns are (t5 exhibit$ ,nor!rn ,g]many ab\nds ) examples ( su* basaltic masses1 :i* h once =m$ ! c5tres ( great c9d]-cones2 b 9 consequ5ce ( ! removal ( ! loose mat]ials & ! surr\nd+ /rata by d5udation1 ^! c5tral res]voirs ( ! volcanoes h be5 left /&+ above ! surface1 & exhibit ! peculi> arrangem5ts ( ! columns =m$ 9 !m dur+ ! process ( cool+4 ,sid5ote3 ,,intrusive ,,lava-,,%eets4 ,b 9 ! majority ( ! m solidly-built composite volcanoes no su* liquid res]voir c be =m$ )9 ! volcanic cone itself4 ,"u ^! circum/ances1 ! lavas1 especially ^? ( m liquid "*1 t5d to =ce passages = !mselves among ! rocks ?r\gh :i* !y are extrud$4 ,:]ev] a weak po9t exi/s1 !re su* lavas w f9d _! way1 & z ! planes ( /ratification 9 s$im5t>y rocks con/itute su* weak places1 we con/antly f9d %eets ( lava ?us ins]t$ betwe5 b$s ( aque\s orig94 ,! areas ov] :i* ^! intrusive %eets ( rock sometimes ext5d may be v great1 b ! m fusible1 basic lavas 7basalt1 c47 usually =m mu* m widely-spread+ %eets ?an ! less fusible1 acid lavas4 ,9 "s cases ^! great intrusive %eets are f\nd ext5d+ to a di/ance ( tw5ty or ?irty miles f ! c5tre at :i* !y 7 eject$1 & !y (t5 foll[ ! b$d+ ( ! /rata ) :i* !y are int]calat$ 9 s regul> a mann]1 t x is difficult = an obs]v] to believe at fir/ sight t !y c h be5 =m$ 9 ! way :i* we h describ$4 ,a clos] exam9ation w g5]ally reveal ! fact t :ile ^! intrusive lava-%eets reta9 _! p>allelism ) ! /rata among :i* !y h be5 intrud$1 ov] consid]able areas1 yet !y sometimes break across1 or s5d (f%oots into !m1 z %[n 9 fig4 #ef4 ,9 all cases1 too1 ! rocks ly+ above & bel[ su* %eets w be f\nd to be m or less bak$ & alt]$1 & ?is af=ds a v conv9c+ evid5ce ( ! intrusion ( ! igne\s mass betwe5 ! /rata s alt]$4 ,illu/ration3 ,fig4 #ef4--,%eets ( ,igne\s ,rock 7,basalt7 intrud$ betwe5 b$s ( s&/one1 clay1 & lime/one4 7,isl& ( ,skye47 ,t 9 ! case ( mo/ great volcanic m\nta9s1 or sy/ems ( m\nta9s1 va/ res]voirs ( liquid lava mu/ exi/ 9 ! e>?'s cru/ f> bel[ ! surface1 !re c be little room = d\bt4 ,:e!r su* fluid masses are 9 direct or indirect communication ) a great c5tral res]voir1 ev5 suppos+ su* to exi/1 is a totally diff]5t "q4 ,9 _m cases ! outbur/ ( volcanoes 9 m or less close proximity has be5 obs]v$ to take place simultane\sly1 :ile 9 o!rs ! comm5cem5t ( ! eruption ( "o volcano has co9cid$ ) ! lapse into quiesc5ce ( ano!r 9 its vic9ity4 ,on ! o!r h&1 ! rem>kable case ( ! volcanoes ( ,hawaii seems to indicate t two v5ts 9 close proximity may be suppli$ f p]fectly di/9ct res]voirs ( lava4 ,! active crat]s ( ,mauna ,loa & ,kilauea are situat$ at ! heights ( #ad1jjj & #d1jjj feet respectively above ! sea level2 yet ! =m] is sometimes 9 a /ate ( viol5t activity1 ) :i* ! latt] %[s no signs ( sympa?y :atev]4 ,we %all1 9 a future *apt]1 adduce evid5ce t ! liquid lavas 9 und]gr\nd res]voirs may und]go v>i\s /ages ( *ange 9 ! enorm\s p]iods ( "t dur+ :i* habitual volcanic v5ts are suppli$ f !m4 ,we h already %[n t ! "* assum$ by a mass ( fus$ mat]ial 9 cool+ v>ies greatly accord+ z ! cool+ takes place rapidly at ! surface or sl[ly "u enorm\s pressure4 ,9 ! =m] case a glassy base is =m$ conta9+ a great] or small] numb] ( cry/allites or embryo cry/als1 9 ! latt] ! :ole rock is conv]t$ into a mass ( fully-develop$ cry/als4 ,sid5ote3 ,,consolidation ,,( ,,lavas ,,at ,,great ,,dep?s4 ,! lavas :i* are p\r$ out at ! surface consi/1 z we h se51 ( a glassy magma 9 :i* a great] or small] numb] ( cry/als are f\nd :i* h be5 borne up f bel[4 ,! great dykes & intrusive %eets consi/ = ! mo/ "p ( a mass ( small or imp]fectly develop$ cry/als 9 :i* a numb] ( l>ge & p]fectly =m$ cry/als are emb$d$4 ,su* rocks are said to h a 'porphyritic' /ructure4 ,! rocks =m$ by ! consolidation ( ! liquid masses 9 ! und]gr\nd res]voirs are f\nd to be p]fectly cry/allis$1 ! cry/als impress+ "o ano!r on e side & mak+ up ! :ole mass to ! exclusion ( any pa/e or magma betwe5 !m4 ,! cry/als 9 ^? rocks :i* h consolidat$ at ^! va/ dep?s exhibit evid5ce1 9 _! enclos$ wat]y solutions & liquefi$ c>bonic acid1 ( ! enorm\s pressures "u :i* !y mu/ h be5 consolidat$4 ,! lavas1 ! m or less porphyritic rocks ( ! dykes & %eets1 & ! p]fectly cry/all9e 7granitic7 rocks ( ! und]gr\nd res]voirs pass into "o ano!r1 h[ev]1 by ! mo/ ins5sible gradations4 ,we sometimes f9d examples ( volcanoes :i*1 by ! action ( d5ud+ =ces1 h _h _! v f\ndations expos$ to our view4 ,su* examples occur 9 ! ,we/]n ,isles ( ,scotl&1 9 ! ,euganean ,hills ne> ,padua 9 ,nor!rn ,italy1 & 9 _m o!r p>ts ( ! e>?'s surface4 ,9 ^! cases we are able to trace ! gr\nd-plan ( ! volcanic pile1 & to /udy ! mat]ials :i* h consolidat$ deep b5ea? ! surface 9 ! v he>t ( ! m\nta94 ,9 /udy+ ^! 'basal wrecks' ( old volcanoes x is always necess>y to be> 9 m9d t ! appe>ance & g5]al *>act]s ( a volcanic rock may be completely disguis$ by *emical *anges go+ on )9 x4 ,x is ?r\gh want ( att5tion to ?is fact t s _m mi/akes 7 made by ! ,w]n]ian s*ool ( geologi/s :o decl>$ t !y c\ld f9d no analogy betwe5 ! basaltic rocks ( ! globe & ! products ( active volcanoes1 & 7 h5ce l$ to ref] ! orig9 ( ! =m] to "s k9d ( 'aque\s precipitation4' ,_m ( ! h>d & cry/all9e m>bles :i* are employ$ z ornam5tal /ones 7 orig9ally loose masses ( %ells & corals1 z we easily p]ceive :5 we exam9e ! poli%$ faces4 ,b ^! incoh]5t heaps ( organic dbris h be5 conv]t$ into a compact & solid rock 9 consequ5ce ( ! mass be+ p5etrat$ by wat] conta9+ c>bonate ( lime 9 solution4 ,cry/als ( ?is sub/ance 7 deposit$ 9 e cavity & int]/ice ( ! mass1 & ?us ! accumulation ( sep>ate organisms 0 gradually trans=m$ to a mat]ial ( great solidity & h>dness4 ,sid5ote3 ,,=mation ,,( ,,amygdaloids4 ,9 precisely ! same way loose heaps ( scori1 lapilli1 or pumice may1 by ! passage ?r\gh !m ( wat] conta9+ v>i\s sub/ances 9 solution1 h _! vesicles fill$ ) cry/als1 & ?us be conv]t$ into ! h>de/ & mo/ solid ( rock-masses4 ,simil>ly ! scoriace\s portions ( lava-/reams h _! vesicles fill$ ) cry/all9e sub/ances deposit$ f a /ate ( solution1 & are ?us conv]t$ into a solid mass :i* may at fir/ sight appe> to (f] b little resemblance to ! vesicul> mat]ials ( rec5t lava-/reams4 ,to ^! vesicul> rocks :i* h _! cavities fill$ ) cry/all9e sub/ances geologi/s apply ! "n ( amygdaloids 7,l4 amygdalus1 an almond74 ,! cavities 9 lava-rocks are usually m or less elongat$1 ow+ to ! movem5t ( ! mass :ile 9 a /ill pla/ic /ate1 & ! cry/all9e mat]ials fill+ ^! cavities take ! almond-l %ape2 h5ce ! "n4 ,:5 ! amygdaloids & alt]$ fragm5t>y ejections ( volcanoes are /udi$ microscopically1 _! true "* is at once made manife/4 ,! exposure ( faces ( ^! alt]$ volcanic rocks to ! wea!r+ influ5ces ( ! atmosph]e1 9 _m cases also causes _! true nature to be reveal$1 ! cry/all9e mat]ials fill+ ! int]/ices & vesicles ( ! mass are dissolv$ away by ! ra9-wat] conta9+ c>bonic acid1 & ! rock rega9s its orig9al cav]n\s /ructure & appe>ance4 ,b ?is repeat$ passage ( wat] ?r\gh volcanic rock-masses may result 9 ! removal ( s l>ge a portion ( _! mat]ials t ! rema9d] crumbles d[n into ! condition ( a clay or mud4 ,9 ! basal wrecks ( volcanoes1 ( :i* we h spok51 we usually f9d only small & fragm5t>y rema9s ( ! great accumulations ( loose & scoriace\s mat]ials :i* orig9ally con/itut$ ! bulk ( ! m\nta9 mass4 ,9 ! c5tre ( ! gr\nd-plan ( su* a d5ud$ volcano we f9d great masses ( highly cry/all9e or granitic rock1 :i* evid5tly occupy va/ fissures brok5 ?r\gh ! s$im5t>y or o!r rocks ^u :i* ! volcanic pile has be5 re>$4 ,^! highly cry/all9e rocks exhibit1 z we h %[n1 cle> evid5ce ( hav+ be5 consolidat$ f a /ate ( fusion ) extreme sl[ness & "u enorm\s pressure1 b _! ultimate *emical composition is id5tical ) t ( ! lavas :i* h be5 eject$ f ! volcano4 ,:51 z frequ5tly happ5s1 ! volcano1 aft] p\r+ out "o k9d ( lava = a c]ta9 p]iod1 has *ang$ ! nature ( its ejections1 & giv5 rise to mat]ials ( diff]5t composition1 we f9d cle> evid5ce ( ! fact 9 /udy+ ! basal wreck or gr\nd-plan ( ! volcano4 ,a great intrusive cry/all9e mass1 ( ! same *emical composition z ! fir/-extrud$ lava1 is f\nd to be r5t asund] & p5etrat$ by a simil>ly cry/all9e mass hav+ ! composition ( ! lavas ( ! second p]iod4 ,?us1 9 ! volcanoes ( ! ,we/]n ,isles ( ,scotl&1 :i* are r$uc$ by ! action ( d5udation to ?is condition ( basal wrecks1 we f9d t rhyolites1 tra*ytes1 & &esites 7 eject$ dur+ ! e>li] p]iods ( _! hi/ory1 & basalts dur+ ! lat] p]iods4 ,illu/ration3 ,fig4 #eg4--,plan ( ! ,dissect$ ,volcano ( ,mull1 9 ! ,inn] ,hebrides4 ,illu/ration3 a ,rocks on :i* ! ,volcano has be5 built up4 b ,great intrusive masses ( acid & int]m$iate rocks4 c ,l>a curr5ts ( basalt :i* h fl[$ f d4 d ,intrusive masses ( gabbros dol]ite4 e ,lava curr5ts :i* h fl[$ f b4 f ,volcanic tuffs & agglom]ates4 ,fig4 #eh4--,section ( ! ,volcano along ! l9e ,a ,b4 ,sid5ote3 ,,anci5t ,,volcano ,,( ,,mull4 ,we p]ceive on /udy+ ! gr\nd-plan ( ^! volcanoes t great masses ( granite1 sy5ite1 & diorite--! cry/all9e repres5tatives ( ! fir/-extrud$ lavas--are p5etrat$ by intrusions ( gabbro--! granitic =m ( ! lat]-eject$ lavas4 ,^! features are admirably illu/rat$ by ! ru9$ volcano n[ con/itut+ ! ,isl& ( ,mull1 "o ( ! ,inn] ,hebrides1 a plan ( :i* is giv5 9 fig4 #eg1 & a section 9 fig4 #eh4 ,?is volcano probably _h a diamet] at its base ( ne>ly ?irty miles1 & a height ( f #aj1jjj to #ab1jjj feet1 b is n[ r$uc$ to a gr\p ( hills few ( :i* exce$ #c1jjj feet 9 height4 ,f ^! great intrusive masses ( highly cry/all9e rocks !re proce$ 9 e direction great spurs or dykes1 :i* are evid5tly ! radiat+ fissures =m$ dur+ ! outwell+ ( igne\s mat]ials f bel[1 inject$ by ^! fluid sub/ances4 ,! rock =m+ ^! dykes is (t5 less p]fectly cry/all9e ?an t :i* con/itutes ! c5tre ( ! mass1 & we may inde$ detect among ! mat]ials ( ^! dykes examples ( e v>iety ( /ructure1 f ! p]fectly cry/all9e granite to ! m or less glassy sub/ance ( lavas4 ,besides ! v]tical or oblique dykes we also f9d horizontal %eets1 :i*1 pass+ f ^! c5tral masses1 h p5etrat$ betwe5 ! surr\nd+ /rata1 (t51 z we h se51 to enorm\s di/ances4 ,= ! sake ( simplicity1 we h spok5 ( ^! gr\nd-plans1 or basal wrecks ( volcanoes1 z con/itut+ a flat pla92 z a matt] ( fact1 h[ev]1 ! unequal h>dness ( ! mat]ials compos+ volcanic m\nta9s causes !m to assume1 "u ! influ5ce ( d5ud+ ag5cies1 a v rugg$ & unev5 surface4 ,! h>d cry/all9e mat]ials fill+ ! c5tral v5t /& up z great m\nta9 gr\ps2 ea* l>ge dyke1 by ! removal ( ! surr\nd+ s(t] mat]ials1 is left z a huge wall-l mass1 :ile ! remnants ( lava-/reams are se5 con/itut+ a numb] ( isolat$ plateaux4 ,! great ,isl& ( ,skye is ! basal wreck ( ano!r volcano :i* 0 also 9 eruption dur+ ,t]ti>y times2 probably1 _m millions ( ye>s ago4 ,?is imm5se volcano _h orig9ally a diamet] at its base ( ab\t ?irty miles1 & a height ( #ab1jjj to #ae1jjj feet1 & mu/ h be5 comp>able to ,etna or ,t5]iffe 9 its dim5sions4 ,at ! pres5t "t1 !re is no?+ left ( ?is va/ pile b ! highly cry/all9e granites & gabbros fill+ up ! great fissures ?r\gh :i* ! eruption ( igne\s mat]ials took place4 ,^!1 worn by d5udation into r\nd$ dome-l masses & wild rugg$ peaks1 con/itute ! ,r$ ,m\nta9s & ,cool9 ,hills ( ,skye1 :i* rise to ! height ( m ?an #c1jjj feet above ! sea-level4 ,f ^! great1 c5tral masses ( cry/all9e rocks1 innum]able radiat+ dykes may be f\nd ris+ ?r\gh ! surr\nd+ rock-masses1 ) isolat$ pat*es ( ! scori & lapilli eject$ f ! volcano1 :i* h "h & !re escap$ removal by d5udation4 ,along :at 7 ! outskirts ( ?is great m\nta9-mass are f\nd flat-topp$ hills1 built up ( lava-/reams1 only small portions ( :i* h escap$ removal by d5udation4 ,sid5ote3 ,,res]voirs ,,b5ea? ,,volcanoes4 ,b ?is we>+ away ( ! /ructure ( a volcanic cone by ! d5ud+ =ces may proce$ ev5 "o /age f>!r1 & we may !n h reveal$ = our inspection & /udy ! mass ( orig9ally fluid mat]ials1 f :i* "o or m volcanoes h be5 f$1 cool$ & consolidat$ 9 _! orig9al res]voir4 ,!re are _m examples ( masses ( granitic or highly cry/all9e rocks1 hav+ precisely ! same composition z ! diff]5t v>ieties ( lavas1 :i* are f\nd ly+ 9 ! mid/ ( ! s$im5t>y rocks1 & s5d+ (f into ^! rocks ve9s & dykes ( ! same composition ) !mselves4 ,no "o :o has c>efully /udi$ ! appe>ances pres5t$ by volcanic m\nta9s 9 diff]5t /ages ( dissection1 by ! action ( d5ud+ =ces1 c avoid recognis+ ^! great granitic masses z ! cool$ res]voirs f :i* volcanoes h 9 all probability be5 suppli$ dur+ e>li] p]iods ( ! e>?'s hi/ory4 ,! eruption ( ^! great masses ( inc&esc5t rock1 impregnat$ ) wat] & acid gases1 ?r\gh /rata ( lime/one1 s&/one1 clay1 coal1 c41 may be expect$ to produce /rik+ & wond]ful *emical *anges 9 ! latt]4 ,nor are we disappo9t$ 9 ^! anticipations4 ,:5ev] we exam9e ! s$im5t>y mat]ials ar\nd volcanic v5ts1 we f9d t1 9 contact ) ! once-fus$ mat]ials1 !y ev]y:]e exhibit rem>kable evid5ces ( ! *emical action to :i* !y h be5 subject$4 ,! lime/ones are conv]t$ into /atu>y m>ble1 ! s&/ones pass into qu>tzite1 ! days assume ! h>dness & lu/re ( porcela91 :ile ! coals h lo/ _! volatile +r$i5ts & assum$ a =m l coke or graphite4 ,& ^! *anges are f\nd to ext5d 9 _m cases to ! di/ance ( _m hundr$s ( y>ds f ! planes ( junction betwe5 ! igne\s & ! s$im5t>y mat]ials4 ,among ! mo/ int]e/+ effects result+ f ! extrusion ( masses ( inc&esc5t rock1 *>g$ ) wat] & v>i\s gases1 ?r\gh b$s ( lime/one1 clay1 s&/one1 c41 we may m5tion ! production ( ^? beautiful cry/all9e m9]als :i* adorn our museums & are s highly priz$ z gems4 ,by f> ! l>g] "p ( ^! beautiful m9]als h be5 =m$1 directly or indirectly1 by volcanic ag5cies4 ,^! gems & beautiful m9]als are1 = ! mo/ "p1 sub/ances ( e-day occurr5ce1 :i* entirely owe _! beauty to ! cry/all9e =ms !y h assum$4 ,! diamond is cry/allis$ c>bon1 ! ruby & sapphire are cry/allis$ alum9a1 ! ame?y/ & a ho/ ( o!r gems are cry/allis$ silica2 & 9 almo/ all cases ! mat]ials ( gems are common & widely diffus$1 x is only 9 _! f9ely cry/all9e condition t !y are r>e & !re=e valuable4 ,sid5ote3 ,,=mation ,,( ,,volcanic ,,m9]als4 ,cry/als are =m$ dur+ ! sl[ deposition ( a sub/ance1 ei!r by ! evaporation ( a liquid 9 :i* x is dissolv$1 by its volatilisation1 or its cool+ f a /ate ( fusion4 ,9 _m cases x c be %[n t ! =mation ( l>ge & regul> cry/als is aid$ if ! "w goes on ) extreme sl[ness & "u great pressure4 ,by seal+ up v>i\s sub/ances 9 tubes conta9+ wat] :i* c be kept at a high temp]ature1 m9ute cry/als ( _m well-kn[n m9]als h be5 artificially =m$ by *emi/s4 ,"p ( ! wat] conv]t$ into /eam has =m$ a p[]ful spr+1 :i*1 react+ ^u ! rema9d] ( ! liquid 9 ! tube1 has subject$ x to enorm\s pressure1 & "u ^! conditions ( extreme pressure & temp]ature1 *emical actions take place ( :i* we h no exp]i5ce "u ord9>y circum/ances4 ,! exp]im5ts ( ,mr4 ,hannay seem to prove t :5 c>bon is sep>at$ f c]ta9 organic sub/ances at a high temp]ature & "u great pressure1 x may cry/allise 9 ! =m ( ! diamond4 ,& ! rec5t discov]y ( diamonds 9 ! mid/ ( mat]ials fill+ old volcanic v5ts 9 ,s\? ,africa seems to %[ t ?is 0 9 _m cases ! mode 9 :i* ! gem 0 orig9at$4 ,ev5 "u ! conditions :i* prevail at ! e>?'s surface1 h[ev]1 m9ute & unnotic$ *emical actions tak+ place dur+ long p]iods ( "t1 produce mo/ rem>kable results4 ,?is has be5 well illu/rat$ by ,m4 ,daubre1 :o has %[n t 9 ! mid/ ( masses ( concrete :i* ! ,romans built up ar\nd ! hot spr+s ( ,plombires & o!r localities1 _m cry/all9e m9]als h be5 =m$1 9 ! c\rse ( #b1jjj ye>s1 by ! action ( ! wat]s ^u ! +r$i5ts ( ! concrete4 ,b mo/ ( ! cry/als ( m9]als :i* h be5 ?us artificially =m$ are ( m9ute1 inde$ (t5 ( microscopic1 dim5sions4 ,9 ! und]gr\nd res]voirs b5ea? volcanoes1 h[ev]1 we h all ! necess>y conditions = ! =mation ( cry/als ( m9]als on a f> gr&] scale4 ,high temp]atures1 pressures f> great] ?an any we c comm& at ! e>?'s surface1 ! action ( sup]heat$ /eam & _m acid gases on ! v>i\s con/itu5ts ( bo? igne\s & s$im5t>y rocks1 &1 above all1 "t ( almo/ unlimit$ duration2 ^! con/itute su* a set ( conditions z may fairly be expect$ to result 9 ! =mation ( cry/als1 simil> to ^? artificially produc$ b ( f> great] size & beauty4 ,if we visit ^? p>ts ( ! e>?'s surface :]e great masses ( fus$ volcanic rock h sl[ly cool$ d[n 9 contact ) s$im5t>y mat]ials1 we %all n be disappo9t$ 9 our expectations4 ,diamonds1 rubies1 sapphires1 em]alds1 topazes1 g>nets1 & a ho/ ( equally beautiful1 if less highly priz$1 cry/all9e sub/ances1 are f\nd 9 su* situations1 ly+ 9 ! subt]ranean *emical laboratories 9 :i* !y h be5 =m$1 b n[1 by ! action ( d5ud+ =ces1 reveal$ to our view4 ,9 "s cases x is n necess>y to p5etrate to ^! subt]ranean laboratories 9 ord] to f9d ^! beautiful gems & o!r cry/allis$ m9]als2 = ! /eam jets :i* issue f volcanic fissures c>ry up fragm5ts ( rock torn f ! side ( ! v5t1 & 9 ! cavities & fissures ( su* eject$ masses beautiful cry/allis$ products are (t5 f\nd4 ,su* rock-fragm5ts conta9+ m9]als f9ely cry/allis$ are f\nd abundantly on ! flanks ( ,vesuvius & o!r active volcanoes1 & among ! mat]ials ( ! ,laa*] ,see & o!r ext9ct volcanoes4 ,sid5ote3 ,,=mation ,,( ,,m9]al-,,ve9s4 ,b x is n only ! f9ely cry/allis$ m9]als & gems :i* we owe to volcanic action4 ,! v>i\s metallic m9]als h ne>ly all be5 br\ght f deep-seat$ portions ( ! e>?'s cru/ & deposit$ ^u ! sides ( rock-fissures by ! ag5cy ( ! same volcanic =ces4 ,x is ^! =ces :i* h1 9 ! fir/ in/ance1 op5$ ! cracks ?r\gh ! solid rock masses2 &1 9 ! second place1 h br\ght ! metallic sulphides1 oxides1 & salts--ei!r 9 fusion1 9 solution1 or 9 a vaporis$ condition--f ! deep-seat$ masses )9 ! e>?1 caus+ !m to cry/allise ^u ! sides ( ! fissures1 & ?us =m ^? metallic lodes & ve9s :i* are )9 rea* ( our m9+ op]ations4 ,!re is /ill "o o!r important class ( m9]als :i* owe ! exi/5ce1 ?\gh indirectly1 to volcanic ag5cies4 ,! cavities ( igne\s rocks1 especially ! vesicles =m$ by ! escape ( /eam1 con/itute1 :5 fill$ ) wat]1 laboratories 9 :i* complicat$ *emical reactions take place4 ,! mat]ials ( ! lava are gradually dissolv$ & re-cry/allis$ 9 new comb9ations4 ,by ?is means ! mo/ beautiful examples ( su* m9]als z ! agates1 ! onyxes1 ! rock-cry/als1 ! ,icel&-sp>s1 & ! num]\s beautiful cry/als class$ toge!r z ',zeolites' h be5 =m$4 ,no "o c visit a l>ge collection ( cry/all9e m9]als )\t be+ /ruck ) ! l>ge numb] ( beautiful sub/ances :i* h ?us be5 =m$ z second>y products f volcanic mat]ials4 ,,*apt] ,,vi4 ,,! ,,v>i\s ,,/ructures ,,built ,,up ,,ar\nd ,,volcanic ,,v5ts ,f :at has be5 said 9 ! prec$+ *apt]s x w be se5 t :ile "s ( ! mat]ials eject$ f volcanic v5ts are1 by ! movem5ts ( ! air & ocean1 di/ribut$ ov] e "p ( ! face ( ! globe1 ano!r1 & by f> ! l>g]1 "p ( ! matt] s eject$1 accumulates 9 ! imm$iate vic9ity ( ! v5t itself4 ,by ?is accumulation ( erupt$ mat]ials1 v>i\s /ructures are built up ar\nd ! orifices f :i* ! ejections take place1 & ! size & "* ( ^! /ructures v>y greatly 9 diff]5t cases1 accord+ to ! quantity & nature ( ! eject$ mat]ials1 & ! int5sity ( ! eruptive =ces by :i* !y 7 ?r[n f ! orifice4 ,we %all proce$ 9 ! pres5t *apt] to notice ! *ief v>ieties 9 ! =ms & *>act]s ( ! heaps ( mat]ials accumulat$ r\nd volcanic v5ts4 ,^! heaps ( mat]ials v>y 9 size f masses no bigg] ?an a mole-heap up to m\nta9s l ,etna1 ,t5]iffe1 & ,*imborazo4 ,! size ( volcanic m\nta9s is pr9cipally det]m9$ by ! conditions ( ! eruptive action at ! v5t ar\nd :i* !y are =m$4 ,if ?is action exhau/s itself 9 a s+le ef=t1 v consid]able volcanic cones1 l ! ,monte ,nuovo ) _m simil> hills 9 its vic9ity1 & ! ,puys ( ,auv]gne1 may be =m$2 b if repeat$ eruptions take place at long] or %ort] int]vals f ! same v5t1 !re appe>s to be sc>cely any limit to ! size ( ! /ructures :i* may1 "u su* conditions1 be =m$4 ,x is by ?is repeat$ action f ! same volcanic v5t go+ on = ?\s&s or ev5 millions ( ye>s1 t ! gr&e/ volcanic m\nta9s ( ! globe h be5 built up4 ,su* volcanoes h sometimes a diamet] at _! base ( f #cj to #ajj miles1 & an elevation ( f #aj1jjj to #be1jjj feet4 ,! =m ( volcanic m\nta9s is det]m9$ 9 "p by ! nature ( ! mat]ials eject$1 & 9 "p by ! "* ( ! eruptive action4 ,f :at has be5 said 9 ! prec$+ *apt]1 x w be ga!r$ t ! volcanoes built up by ejections ( fragm5t>y mat]ials diff] 9 _m /rik+ p>ticul>s f ^? =m$ by ! outwell+ ( lavas f volcanic v5ts4 ,9 a less degree1 ! volcanoes compos$ ( ! same k9d ( volcanic mat]ials also v>y among !mselves4 ,sid5ote3 ,,*>act]s ,,( ,,scoria-,,cones4 ,:5 masses ( scori 9 a semi-fluid condition are ?r[n to only a little di/ance above ! volcanic v5t1 s t !y h n "t to assume a p]fectly solid condition be=e !y fall r\nd ! v5t1 ! rugg$ masses ( lava unite to =m heaps ( mo/ irregul> %ape4 ,9 su* cases1 ! fall+ fragm5ts be+ 9 a semi-pla/ic /ate1 /ick to ! masses bel[1 & d n t5d to roll d[n ! sides ( ! heap4 ,irregul> heaps ( su* volcanic scori ab\nd on ! surfaces ( lava-/reams1 be+ pil$ up ar\nd ea* 'bocca' or v5t :i* ! /eam-jets escap+ f ! lava-curr5ts =m at _! surfaces4 ,su* irregul> accumulations ( scori 7 obs]v$ on ! lavas ( ,vesuvius dur+ ! eruptions ( #ahbb1 #ahee1 & #ahgb1 & h also be5 describ$ 9 ! case ( _m o!r volcanoes4 ,9 fig4 #bf 7p4 #aja7 we h giv5 repres5tations ( a gr\p ( su* irregul> scoria-cones :i* 0 obs]v$ by ,s*midt on ! ,vesuvian lava ( #ahee4 ,x w be se5 f ?is draw+ t !re is sc>cely any limit to ! /eepness ( ! sides ( su* scoria-heaps1 9 :i* ! mat]ials are 9 an imp]fectly solidifi$ condition :5 !y rea* ! gr\nd4 ,b 9 ! majority ( cases1 ! scori eject$ f volcanic v5ts are ?r[n to a great height1 & are 9 a m or less p]fectly solidifi$ condition :5 !y fell to ! gr\nd aga94 ,9 su* cases ! fragm5ts obey ! ord9>y me*anical laws ( fall+ bodies1 roll+ & slid+ ov] "o ano!r1 till !y acquire a slope :i* v>ies accord+ to ! size & =m ( ! fragm5ts4 ,9 ?is way ! great conical m\nds are =m$ :i* are kn[n z 'c9d]-cones1' or m prop]ly z 'scoria-cones4' ,scoria-cones usually v>y 9 ! slope ( _! sides f #ce to #dj & may diff] 9 size f m]e monticules to hills a ?\s& feet or m 9 height4 ,scoria-cones ( ?is "* ab\nd 9 _m volcanic di/ricts1 z ! ,auv]gne1 :]e !y may be numb]$ by ?\s&s4 ,! mat]ials =m+ su* scoria-cones v>y 9 size f t ( a nut to masses z l>ge z a man's head1 & fragm5ts ( ev5 l>g] dim5sions are by no means uncommon4 ,:5 ! lava 9 a volcanic v5t is p]fectly glassy1 in/ead ( be+ p>tially cry/all9e 9 /ructure1 we f9d n scori b pumice eject$4 ,9 su* cases1 z 9 ! ,lip>i ,isl&s = example1 we see cones entirely built up ( pumice4 ,su* pumice-cones resemble 9 ! angle ( _! slope 7see fig4 #da1 fac+ p4 #abd71 ! ord9>y scoria-cones1 b are ( a brilliant :ite col\r1 appe>+ z if cov]$ ) sn[4 ,sid5ote3 ,,pres]vation ,,( ,,scoria-,,cones4 ,ord9>y scori are usually ( a black col\r :5 fir/ eject$1 b aft] a %ort "t ! black oxide ( iron 7magnetite7 :i* !y conta91 attracts ! oxyg5 ( ! air & moi/ure1 & assumes ! r$di%-br[n col\r ( iron-ru/4 ,"u su* circum/ances ! heaps ( black mat]ial gradually acquire ! r$-br[n col\r :i* is *>act]i/ic ( s _m ( ! scoria-cones ar\nd ,etna1 & 9 ! ,auv]gne & ! ,eifel4 ,! moi/ure ( ! air1 & ! ra9 fall+ ^u ^! loose c9d]y heaps1 cause !m to decompose ^u _! surfaces2 ! action is facilitat$ by ! gr[? ( ! l[] =ms ( vegetation1 su* z mosses & li*5s1 & ?us at la/ a soil is produc$ on ! surfaces ( ^! conical piles ( loose mat]ials :i* may support an abundant vegetation4 ,c9d]- or scoria-cones are n uncommonly f\nd reta9+ 9 a mo/ p]fect mann] _! regul>1 conical =m1 ! lips ( _! crat]s be+ %>p & unbrok5 z if ! cone 7 =m$ b ye/]day1 :ile _! slopes may nev]!less be cov]$ ) a ri* soil support+ abundant grass & =e/-trees4 ,x may at fir/ sight seem difficult to und]/& h[ a loose mass ( scori c\ld h s long )/ood ! action ( ! ra9 & floods1 reta9+ s p]fectly its ev5 slopes & %>p ridges4 ,a little consid]ation w1 h[ev]1 conv9ce u t x is ! v loose & p]vi\s nature ( ! mat]ials ( :i* scoria-cones are compos$1 :i* t5ds to _! p]fect pres]vation4 ,! ra9 at once s9ks into _! mass1 be=e x has "t to =m rivulets & /reams :i* w\ld we> away _! surfaces & de/roy ! regul>ity ( _! outl9es4 ,scoria- & pumice-cones are frequ5tly f\nd to be act$ ^u by acid vap\rs to su* an ext5t t ! :ole ( ! mat]ials is r$uc$ to a :ite pulv]ul5t mass4 ,9 ^! cases ! oxides ( iron & ! alkalis h unit$ ) ! sulphuric or hydro*loric or c>bonic acids1 ! comp\nds be+ c>ri$ away 9 solution by ! ra9-wat] fall+ on ! mass2 ! mat]ials left are silica1 ! hydrat$ silicate ( alum9a1 & hydrat$ sulphate ( lime 7gypsum71 all ( :i* are ( a :ite col\r4 ,c9d]- or scoria-cones1 & pumice-cones1 are (t5 f\nd rais$ by ! action ( w9ds to a great] elevation on "o side ?an ! o!r1 9 ! mann] already describ$4 ,"o side ( ! cone is (t5 se5 to be m or less completely swept away by an outwell+ /ream ( lava1 & ?us brea*$ cones are =m$ 7see fig4 #dj1 p4 #abc74 ,n unfrequ5tly we f9d a numb] ( cones :i* are unit$ m or less completely at _! bases1 z 9 ,vulcanello 7fig4 #f1 p4 #dc71 ! sev]al v5ts be+ s ne> toge!r t _! ejections h m+l$ ) "o ano!r4 ,cones compos$ entirely ( fragm5t>y mat]ials (t5 %[ an approa* to ! beautifully curv$ slopes :i* we h describ$ z be+ s *>act]i/ic ( volcanoes1 z may be se5 9 fig4 #da1 fac+ p4 #abd4 ,9 ! case ( scoria- & pumice-cones ?is curvature is probably due to ! roll+ d[nnw>ds & outw>ds ( ! l>g] fragm5ts4 ,we h already po9t$ out t ) ! scori !re are (t5 eject$ fragm5ts torn f ! sides ( ! volcanic v5ts4 ,sometimes su* fragm5ts are s num]\s z to make up a consid]able portion ( ! mass ( ! volcanic cones4 ,?us 9 ! ,eifel we f9d hills1 ( by no means insignificant size1 completely built up ( small scori & brok5 fragm5ts ( slate torn f ! rocks ?r\gh :i* ! volcanic fissures h be5 op5$4 ,occasionally we see t few or no scori h be5 eject$1 & ! volcanic v5ts are surr\nd$ simply by heaps ( burnt slate4 ,! small] fragm5t>y mat]ials eject$ f volcanic v5ts--su* z lapilli & du/--re/ 9 heaps1 hav+ a diff]5t angle ( slope f ^? =m$ by scori4 ,9 _m cases1 z we h se51 su* f9ely-divid$ mat]ials desc5d 9 ! condition ( mud1 :i* fl[s ev5ly ov] ! surface ( ! gr[+ cone & consolidates 9 b$s ( v regul>ly /ratifi$ 'tufa' or 'tuff4' ,sid5ote3 ,,*>act]s ,,( ,,tuff-,,cones4 ,! 'tuff-cones' ?us =m$ diff] 9 _m important respects f ! scoria-cones already describ$4 ,! slope ( _! sides v>ies f #ae to #cj1 & is almo/ always consid]ably less ?an 9 scoria- & pumice-cones4 ,! tuff-cones und]go mu* m rapid degradation f ra9 & moi/ure ?an d ! scoria-cones2 =1 ?\gh ! mat]ials ( ! =m] 'set1' z we h se51 into a sub/ance ( consid]able h>dness1 yet ?is sub/ance1 be+ mu* less p]vi\s to wat] ?an ! loose scoria heaps1 p]mits ( ! =mation ( surface-/reams :i* furr[ & we> away ! sides ( ! cones4 ,sometimes ! sides ( ! crat] are f\nd to be almo/ :olly remov$ by atmosph]ic d5udation1 & only a %all[ depression is f\nd occupy+ ! site ( ! crat]2 su* a case is repres5t$ 9 fig4 #ei4 ,we n unfrequ5tly f9d ! :ole slopes ( su* cones to be trav]s$ by a s]ies ( radiat+ grooves pass+ f ! summit to ! base ( ! m\nta9s1 ^! *annels be+ =m$ by wat]1 :i* has collect$ into /reams1 fl[+ d[n ! slopes ( ! m\nta9s4 ,! volcanic cone1 "u ^! circum/ances1 frequ5tly pres5ts ! appe>ance ( a p>tially op5$ umbrella4 ,ow+ to ! imp]vi\s "* ( ! mat]ials compos+ tuff-cones1 _! crat]s are frequ5tly f\nd to be occupi$ by lakes4 ,illu/ration3 ,fig4 #ei4--,summit ( ! volcano ( ,monte ,sant' ,angelo 9 ,lip>i exhibit+ a crat] ) walls worn d[n by d5udatioh4 ,tufas h usually a :ite or yell[i%-br[n col\r1 & ^! are ! col\rs exhibit$ by ! cones compos$ ( ?is mat]ial be=e !y become cov]$ by vegetation4 ,tufas scori1 & lavas usually crumble d[n to =m a v ri* soil1 & _m ( ! *oice/ w9es are produc$ f grapes gr[n on ! f]tile slopes ( volcanic m\nta9s4 ,:51 h[ev]1 z n unfrequ5tly happ5s1 ! mat]ials are f9ely divid$ & incoh]5t1 !y are s easily driv5 ab\t by ! w9ds t cultivation ( any k9d is r5d]$ almo/ impossible4 ,9 ! ,isl&s ( ,/romboli & ,vulcano ! g>d5s h to be surr\nd$ by high f5ces to prev5t !m f be+ ov]:elm$ by ! ev]-%ift+ masses ( volcanic s&4 ,sid5ote3 ,,*>act]s ,,( ,,lava-,,cones4 ,!re are "s cones :i* are compos$ 9 "p ( scori & 9 "p ( tufa4 ,h5ce we are sometimes at a loss :e!r to gr\p !m ) ! "o class ( cones or ! o!r4 ,b 9 ! majority ( cases1 scoria- & tuff-cones pres5t ! suffici5tly well-m>k$ & di/9ctive *>act]s :i* we h describ$4 ,lava-cones diff] q z greatly 9 _! =ms z d ! cones compos$ ( fragm5t>y mat]ials1 ! v>iations be+ pr9cipally det]m9$ by ! degree ( liquidity ( ! lavas4 ,we sometimes f9d t outwell+ masses ( lava1 :5 issu+ 9 small quantities f a v5t1 accumulate 9 caulifl[]-%ap$ masses1 or sometimes 9 ! =m ( a column1 or bottle4 ,pr(essor ,j4 ,d4 ,dana describes _m su* fanta/ically-=m$ masses ( lava z be+ f\nd 9 ,hawaii1 "o ( :i* is repres5t$ 9 fig4 #be 7p4 #ajj74 ,:5 ! lava issues f ! v5t 9 great quantities x t5ds to fl[ on all sides ( x1 & to build up a great conical heap above ! orifice4 ,if ! lava be v liquid x fl[s to great di/ances1 re/+ at a v slight slope4 ,?us we f9d t ! volcanoes ( ,hawaii h be5 built up ( successive ejections ( v liquid lava1 :i* h =m$ cones hav+ a slope ( only #f to #h1 b ( su* enorm\s dim5sions t ! diamet] ( _! bases is sev5ty miles & _! height #ad1jjj feet4 ,illu/ration3 ,fig4 #fj4--,outl9es ( ,lava-cones4 #a4 ,mauna ,loa1 9 ,hawaii4 ,compos$ ( v fluid lava4 #c4 ,! ,s*lossb]g ( ,teplitz1 ,bohemia4 ,compos$ ( v imp]fectly fluid or viscid lava4 ,if1 on ! o!r h&1 ! lava be viscid1 or v imp]fectly liquid 9 "*1 x t5ds to accumulate imm$iately ar\nd ! v5t2 fre% ejections =ce ! fir/ extrud$ matt] outw>ds1 9 ! mann] s well illu/rat$ by ,dr4 ,rey]'s exp]im5ts1 & at la/ a m or less /eep-sid$ bulb\s mass is =m$ ov] ! v5t4 ,su* bulb\s masses1 compos$ ( imp]fectly fluid lavas1 occur 9 _m volcanic di/ricts1 & con/itute hills ( consid]able size4 ,f ! t5d5cy ( matt]s ?us extrud$ to *oke up ! v5ts1 h[ev]1 ^! volcanoes compos$ ( viscid lavas _c be expect$ to atta9 ! va/ dim5sions rea*$ by "s ( ^? compos$ ( v liquid lavas4 ,! diff]5ce 9 ! =ms ( lava-cones compos$ ( v fluid or ( some:at viscid mat]ials is illu/rat$ 9 fig4 #eh4 ,:5 ! int]ior ( su* /eep-sid$ volcanic m\nta9s compos$ ( viscid mat]ials is expos$ by ! action ( d5ud+ =ces1 ! peculi> int]nal /ructure we h describ$ is display$ by !m4 ,9 ! ,*odi-,b]g ( ,hung>y1 a great bulb\s mass ( &esitic rock1 ?is endog5\s /ructure is admirably display$4 ,x is also well se5 9 ! excavation ( ! hill ( ! ,gr& ,s>c\i1 a simil> mass1 compos$ ( alt]$ tra*yte1 :i* has be5 erupt$ 9 ! mid/ ( a scoria-cone 9 ! ,auv]gne4 ,see fig4 #dd 7p4 #abf74 ,sid5ote3 ,,*>act]s ,,( ,,composite ,,cones4 ,mo/ ( ! great volcanic m\nta9s ( ! globe belong to ! class ( 'composite cones1' & are built up by alt]nate ejections ( fluid lava & fragm5t>y mat]ials4 ,! slope ( ! sides 9 su* composite cones is subject to a wide range ( v>iation1 be+ det]m9$ 9 "p by ! degree ( liquidity ( ! lavas1 9 "p by ! nature ( ! fragm5t>y mat]ials eject$1 & 9 "p by ! proportions :i* ! fragm5t>y & lava-ejections be> to "o ano!r4 ,b !re is ano!r set ( causes :i* t5ds to modify ! =m & "* ( ^! composite1 volcanic cones4 ,z we h already po9t$ out1 ! sides ( su* cones are liable to be r5t asund] f "t to "t1 & ! fissures s produc$ are inject$ ) masses ( liquid lava f bel[4 ,^! fissures1 r5t 9 ! sides ( volcanic cones1 (t5 rea* ! surface & eruptive action takes place1 giv+ rise to ! =mation ( a cone1 or s]ies ( cones1 ^u ! l9e ( ! fissure 7fig4 #fa74 ,su* small cones ?r[n up on ! flanks ( a great volcanic m\nta9 are kn[n z 'p>asitic cones'2 ?\gh subord9ate to ! great m\nta9 mass1 !y may be 9 !mselves ( consid]able dim5sions4 ,among ! hundr$s ( p>asitic cones :i* /ud ! flanks ( ,etna1 !re are "s :i* are ne>ly #hjj feet 9 height4 ,illu/ration3 ,fig4 #fa4--;,diagram illu/rat+ ! =mation ( ,p>asitic ,cones along l9es ( fissure =m$ on ! flanks ( a great volcanic m\nta94 ,illu/ration3 ,fig4 #fb4--,outl9e ( ,etna1 z se5 f ,catania4 ,sid5ote3 ,,=mation ,,( ,,p>asitic ,,cones4 ,! build+ up ( p>asitic cones ^u ! flanks ( a volcanic m\nta9 t5ds1 ( c\rse1 to de/roy its regul> conical =m4 ,?is may be well se5 9 ,etna1 :i*1 by ! accumulation ( mat]ials ^u its flanks1 has become a rem>kably 'r\nd-%\ld]$' m\nta94 7,see figs4 #fb & #fc47 ,at ! same "t x mu/ be rememb]$ t mat]ials erupt$ f ! c5tral v5t t5d to fill up ! holl[s betwe5 ^! p>asitic cones1 & ?us to re/ore to ! m\nta9 its regul>ly conical =m4 ,illu/ration3 ,fig4 #fc4--,outl9e ( ,etna1 z se5 f ! ,val del ,bronte4 ,illu/ration3 ,fig4 #fd4--,plan ( ! ,volcano =m+ ! ,isl& ( ,is*ia4 a1 a1 a4 ,! semi-circul> crat]-r+ ( ,epomeo4 b1 c1 d4 ,lava-curr5ts :i* h fl[$ f ! pr9cipal crat]4 e1 f1 g1 h4 ,plateaux =m$ by anci5t lava-curr5ts4 k4 ,montagnone4 l4 ,monte ,rot>o4 m4 ,monte ,tabor4 ,p>asitic cones & crat]s on ! slopes n4 ,ca/iglione4 ( ! m\nta94 o4 ,lago di ,bagno4 p4 ,! ,cremate4 r4 ,lava-/ream ( ! ,arso1 :i* fl[$ f ! ,cremate 9 #acja4 x1 x1 x4 ,rais$ bea*es on ! %ores ( ! isl&1 %[+ t x has rec5tly und]gone elevation4 ,! ,isl& ( ,is*ia is a good example ( a great volcanic cone ! flanks ( :i* are cov]$ ) num]\s small p>asitic cones4 ,:ile ! great c5tral volcano has evid5tly be5 long ext9ct1 & "o side ( its crat]-wall is completely brok5 d[n1 "s ( ! small p>asitic cones ar\nd its base h be5 =m$ )9 ! hi/orical p]iod--"o ( !m z rec5tly z ! ye> #acjb4 ,fig4 #fd is a plan ( ! ,isl& ( ,is*ia1 %[+ ! num]\s p>asitic cones scatt]$ ov] ! slopes ( ! pr9cipal cone4 ,illu/ration3 ,fig1 #fe4--;,a prim>y ,p>asitic ,cone ) a second>y "o at its base--,is*ia4 a4 ,monte ,rot>o4 b4 ,monte ,tabor4 c4 ,lava-/ream fl[+ f ! latt]4 ,9 "o case we f9d t a p>asitic cone1 ! ,monte ,rot>o1 has itself a simil> small] cone1 :i* is p>asitic to x1 at its foot2 ?is second>y p>asitic cone gives (f a small lava-/ream ( tra*yte1 :i* has fl[$ d[n to ! sea4 7,see fig4 #fe47 ,illu/ration3 ,fig4 #ff4--,scoria-cone ne> ,auckl&1 ,new ,zeal&1 ) a lava-curr5t fl[+ f x4 ,! /rata b5ea? ! volcanic cone are expos$ 9 ! sea-cliff1 & exhibit pro(s ( depression hav+ tak5 place4 ,illu/ration3 ,fig4 #fg4--,section ( rocks bel[ ! anci5t triassic volcano ( ,pr$azzo 9 ! ,tyrol4 ,! position ( ! /rata a b c1 etc41 indicates a c5tral subsid5ce4 ,sid5ote3 ,,subsid5ce ,,b5ea? ,,volcanic ,,v5ts4 ,mo/ great volcanic m\nta9s exhibit a t5d5cy t[>ds a subsid5ce ( _! c5tral portions1 :i* may take place ei!r dur+ or subsequ5tly to _! p]iod ( activity4 ,:5 we exam9e ! /rata ^u :i* a volcano has be5 built up1 b :i* are n[ expos$ to our /udy by d5ud+ =ces1 we usually f9d t !y incl9e t[>ds ! c5tre ( ! eruptive activity4 7,see figs4 #ff & #fg47 ,two causes may contribute to br+ ab\t ?is result4 ,9 ! fir/ in/ance1 we mu/ rem>k t ! pil+ up ( mat]ials ar\nd ! volcanic v5t causes ! subjac5t /rata to be subject$ to a degree ( pressure f> is excess ( t :i* acts ^u ! surr\nd+ rocks4 ,& secondly1 x mu/ be borne 9 m9d t ! cont9ual removal ( mat]ial f bel[ ! m\nta9 mu/ t5d to ! production ( holl[s1 into :i* ! ov]ly+ /rata w s9k4 ,! effect ( ?is c5tral subsid5ce is to give to ! flanks ( volcanic cones ^? beautifully curv$ outl9es :i* con/itute s /rik+ a feature 9 ,vesuvius 7see fig4 #ag1 p4 #hg71 ,fusiyama 7see fig4 #gg1 ,no4 #a1 fac+ p4 #agh71 & _m o!r volcanic m\nta9s4 ,!re seems1 at fir/ sight1 to be sc>cely any limit to ! dim5sions :i* ^! great composite volcanic cones may atta93 ! lat]al eruptions t5d+ to enl>ge ! area ( ! base ( ! m\nta91 &1 by ! injection ( ! fissures1 to knit toge!r & /r5g!n its /ructure1 :ile ! c5tral eruptions cont9ually increase ! elevation ( ! mass4 ,great1 h[ev]1 z is ! =ce :i* is conc]n$ 9 ! production ( our t]re/rial volcanoes1 x has its limits2 &1 at la/1 ! pil+ up ( mat]ials w h gone on to su* an ext5t1 t ! active =ces b5ea? ! volcano are no long] compet5t ei!r to raise mat]ials to ! elevat$ summit ( ! m\nta9 or to te> asund] its /r5g!n$ & =tifi$ flanks4 ,"u ^! circum/ances1 ! volcanic =ces1 if !y h n already exhau/$ !mselves1 w be compell$ to f9d weak places 9 ! di/rict surr\nd+ ! volcano1 at :i* fissures may be produc$ & ! ph5om5a ( eruption display$4 ,sid5ote3 ,,%ift+ ,,( ,,volcanic ,,foci4 ,"s volcanic cones exhibit evid5ce t dur+ ! s]ies ( eruptions by :i* !y h gradually be5 built up1 ! c5tre ( volcanic action has %ift$ to ano!r po9t )9 ! m\nta94 ,?us ,lyell has %[n1 9 ! case ( ,etna1 t dur+ ! e>li] p]iods 9 ! hi/ory ( ! m\nta9 ! pil+ up ( mat]ials w5t on ar\nd a c5tre :i* is n[ situat$ at a di/ance ( ne>ly f\r miles f ! pres5t focus ( eruptive activity4 ,"s ( our old ,briti% volcanoes1 ( :i* ! d5ud$ wrecks exi/ 9 ! ,we/]n ,isles ( ,scotl&1 %[ simil> evid5ce ( a %ift+ ( ! axis ( eruption4 ,"o ( ! mo/ conspicu\s features ( a volcanic cone is ! great depression or crat] f\nd at its summit4 ,9 describ+ ! int]nal /ructure ( volcanic cones1 we h se5 h[ ^! crat]s are produc$ & acquire _! inv]t$ conical =m1 by ! slipp+ & roll+ back ( mat]ials t[>ds ! c5tre ( eruptive action4 ,almo/ all volcanic cones exhibit crat]s1 b 9 ^? :i* are =m$ entirely by ! outwell+ ( viscid lavas ! c5tral depression is (t5 slight & inconspicu\s1 & occasionally altoge!r want+4 ,x frequ5tly happ5s1 h[ev]1 t eruptive action has ceas$ at ! c5tre ( a volcano1 & its summit-crat] may by d5udation be entirely de/roy$1 :ile new & active crat]s are =m$ ^u its flanks4 ,/romboli furni%es u ) an admirable example ( ?is k9d 7see fig4 #a1 fac+ p4 #aj74 ,o!r volcanoes may exhibit sev]al crat]s1 "o at ! summit ( ! m\nta9 & o!rs ^u its flanks4 ,( ?is we f9d a good example 9 ,vulcano 7fig4 #f1 p4 #dc74 ,illu/ration3 ,fig4 #fh4--;,cotopaxi 7#ai1fjj feet71 z se5 f a di/ance ( n9ety miles4 ,:5 a volcano has be5 built up by regul> & cont9u\s eruptions f ! same volcanic v5t1 ! size ( ! crat] rema9s ! same1 :ile ! volcano cont9ually gr[s 9 height & 9 ! diamet] ( its base4 ,! size ( ! crat] w be det]m9$ by ! eruptive =ce at ! volcanic c5tre1 ! size ( ! m\nta9 by ! duration ( ! volcanic activity & ! quantity ( mat]ial eject$4 ,9 ! e>lie/ /age ( its hi/ory1 su* a volcano w resemble ,monte ,nuovo1 :i* has a crat] rea*+ d[n almo/ to ! base ( ! m\nta92 9 ! lat] /ages ( its hi/ory1 su* a volcano w resemble ,cotopaxi 7fig4 #fh7 & ,citlaltepetl 7fig4 #fi71 9 :i* ! crat]1 ?\gh ( f> great] absolute dim5sions ?an t ( ,monte ,nuovo1 be>s b a small proportion to ! va/ cone at ! summit ( :i* x is situat$4 ,illu/ration3 ,fig4 #fi4--;,citlaltepetl1 or ! ,pic d',orizaba1 9 ,mexico 7#ag1cgj feet71 z seem f ! =e/ ( ,xalapa4 ,sid5ote3 ,,orig9 ,,( ,,volcanic ,,crat]s4 ,9 ! great majority ( volcanoes1 h[ev]1 eruptive action does n g on by any means regul>ly & cont9u\sly1 b t]rible p>oxysmal outbur/s occur1 :i* sudd5ly enl>ge ! dim5sions ( ! crat] to an enorm\s ext5t4 ,9 ! ye> #aggb1 !re occurr$ a volcanic eruption 9 ! ,isl& ( ,java1 :i* is p]haps ! mo/ viol5t & t]rible t has happ5$ )9 ! hi/orical p]iod4 ,a l(ty volcanic cone1 call$ ,pap&ayang1 #i1jjj feet high1 bur/ into eruption1 &1 9 a s+le night1 #cj1jjj1jjj1jjj cubic feet ( mat]ials 7 ?r[n into ! atmosph]e1 fall+ ^u ! c\ntry ar\nd ! m\nta9 :]e no less ?an =ty villages 7 buri$4 ,aft] ! eruption1 ! volcano 0 f\nd to h be5 r$uc$ 9 height f #i1jjj to #e1jjj feet1 & to pres5t a va/ crat] 9 its mid/1 :i* _h be5 =m$ by ! ejection ( ! enorm\s mass ( mat]ials4 ,_m simil> cases might be cit$ ( ! removal ( a great "p ( a m\nta9-mass by a sudd51 p>oxysmal outbur/4 ,9 "s cases1 inde$1 ! :ole mass ( a m\nta9 has be5 bl[n away dur+ a t]rific eruption1 & ! site ( ! m\nta9 is n[ occupi$ by a lake4 ,?is is said to h be5 ! case ) ! ,isl& ( ,timor1 :]e an active volcano1 :i* 0 visible f a di/ance ( #cjj miles at sea1 has entirely disappe>$4 ,! removal ( ! c5tral portion ( great volcanic m\nta9s by explosive action1 gives rise to ! =mation ( ^? va/1 circul>1 crat]-r+s ( :i* su* rem>kable examples occur 9 _m volcanic di/ricts4 ,^! crat]-r+s pres5t a wall ) an out] slope agree+ ) t ( ! volcanic cone ( :i* !y orig9ally =m$ a "p1 b ) /eep inn] cliffs1 :i* exhibit good sections ( ! b$s ( tuff1 a%1 & lava ) ! int]sect+ dykes ( :i* ! orig9al volcano 0 built up4 ,ne> ,naples1 "o ( ^! crat]-r+s1 ) slop+ out] sides & /eep inn] ones1 is employ$ to =m ! royal game-pres]ve ( ,a/roni1 ! only entrance to ! crat] be+ clos$ by gates4 ,sid5ote3 ,,=mation ,,( ,,crat]-,,lakes4 ,z ^! crat]-r+s are usually compos$ ( mat]ials m or less imp]vi\s to wat]1 !y (t5 become ! site ( lakes4 ,! beautiful circul> lake ( ,laa*1 9 ! ,rh9e ,prov9ces1 ) ! num]\s simil> examples ( ,c5tral ,italy--,albano1 ,nemi1 ,bracciano1 & ,bols5a--! lakes ( ! ,campi ,phlegri 7,agnano1 ,av]nus1 c471 & "s simil> lakes 9 ! ,auv]gne1 may be adduc$ z examples ( crat]-r+s :i* h become ! site ( lakes4 ,illu/ration3 ,fig4 #gj4--,lac ,pav51 9 ! ,auv]gne4 a4 ,scori4 b4 ,basalt4 ,"o ( ! mo/ beautiful ( ! crat]-lakes 9 ! ,auv]gne is ,lac ,pav5 7fig4 #gj71 :i* lies at ! foot ( a scoria-cone1 ,mont ,*alme1 & is itself surr\nd$ by masses ( eject$ mat]ials4 ,! crat]-lake ( ,bagno1 9 ,is*ia 7fig4 #ga71 has _h a *annel cut betwe5 x & ! sea1 s t x s]ves z a natural h>b\r4 ,! lake ( ,gu/avila1 9 ,mexico 7fig4 #gb71 is an example ( a crat]-lake on a mu* l>g] scale4 ,9 _m ( ^! crat]-r+s ! diamet] ( ! circul> space enclos$ by !m is (t5 v great inde$ z comp>$ ) ! height ( ! walls4 ,illu/ration3 ,fig4 #ga4--,! crat]-lake call$ ,lago del ,bagno1 9 ,is*ia1 conv]t$ into a h>b\r4 ,illu/ration3 ,fig4 #gb4--,lake ( ,gu/avila1 9 ,mexico4 7,! t]races r\nd ! lake h be5 artificially =m$47 ,sid5ote3 ,,dim5sions ,,( ,,crat]-,,lakes4 ,two ( ! l>ge/ crat]-r+s 9 ! _w are f\nd 9 ,c5tral ,italy1 & are bo? occupi$ by lakes1 ! circul> =ms ( :i* mu/ /rike e obs]v]4 ,! ,lago di ,bracciano1 :i* lies to ! nor?-we/ ( ,rome1 is a circul> lake six & a half miles 9 diamet]1 surr\nd$ by hills :i* at _! highe/ po9t rise to ! height ( #a1dhf feet above ! sea1 :ile ! surface ( ! wat]s ( ! lake is #fdj feet above ! sea-level4 ,! ,lago di ,bols5a is some:at less p]fectly circul> 9 outl9e ?an ! ,lago di ,bracciano2 x has a l5g? f nor? to s\? ( t5-&-a-qu>t] miles & a bread? f ea/ to we/ ( n9e miles2 ! surface ( ! wat]s ( ?is lake is #ifb feet above t ( ! wat]s ( ! ,m$it]ranean4 ,! lake ( ,bols5a1 l t ( ,bracciano1 is surr\nd$ by hills compos$ ( volcanic mat]ials2 ! highe/ po9ts ( ?is r+ ( hills rise to elevations ( #fhd1 #ghj1 & #ihe feet respectively above ! wat]s ( ! lake4 ,9 ^! great circul> lakes ( ,bols5a & ,bracciano1 z well z 9 ! small] ones ( ,albano1 ,nemi1 & ! lakes ( ,frascati 9 ! same di/rict1 ! va/ circul> spaces enclos$ by !m1 ! gradual out] slope ( ! r+1 & ! inn] precipices :i* b\nd ! lake1 all af=d evid5ce ( ! explosive action to :i* !y owe _! orig94 ,b :ile ! va/ crat]-r+s we h m5tion$ are frequ5tly f\nd to be occupi$ by lakes1 !re are _m o!r simil> crat]-r+s :i* rema9 dry1 ei!r f ! mat]ials ( :i* !y are compos$ be+ ( m p]vi\s "*1 or f riv]s hav+ cut a *annel ?r\gh ! walls ( ! crat]1 9 ?is way dra9+ (f its wat]s4 ,?us 9 ! ,campi ,phlegri1 :ile we h ! crat]s ( ,agnano & ,av]nus =m+ complete circul> lakes1 ,a/roni has only a few insignificant lakelets on its floor1 & ! ,pianura1 ! ,piano di ,qu>to1 :i* h ea* a diamet] ( ?ree or f\r miles1 ) _m o!rs1 rema9 p]fectly dry4 ,9 ! vic9ity ( ! great crat]-lakes ( ,c5tral ,italy we f9d ! crat]-r+ ( ! ,vall>iccia1 :i* has evid5tly once be5 a lake b is n[ dra9$1 its floor be+ cov]$ ) villages & v9ey>ds4 ,sid5ote3 ,,crat]-,,r+s ,,surr\nd+ ,,cones4 ,a comp>ison ( ^! va/ crat]-r+s leads u to ! conclusion t 9 ! majority ( cases1 if n 9 e in/ance1 !y are compos$ almo/ entirely ( volcanic tuff & du/4 ,9 ! case ( ! m solidly-built composite volcanic cones1 ! volcanic =ces1 z we h se51 produce fissures 9 ! mass1 & along ^! fissures p>asitic cones are ?r[n up1 ! t5sion ( ! mass ( imprison$ vap\rs bel[ ! m\nta9 be+ ?us f "t to "t reliev$4 ,b 9 ! case ( a volcanic cone compos$ ( loose fragm5t>y mat]ials1 su* tempor>y relief is impossible4 ,! cracks1 z soon z !y orig9ate1 w be fill$ up & *ok$ by ! fall+ 9 ( mat]ials f above & at _! sides4 ,9 ?is way ! eruptive action w be cont9ually repress$1 till at la/ ! imprison$ vap\rs acquire su* a high /ate ( t5sion t ! outbur/1 :5 x occurs1 is ( ! mo/ t]rible "*1 & ! :ole c5tral mass ( ! volcano is bl[n into ! air4 ,x may (t5 seem surpris+ t ! ejection ( su* va/ masses ( mat]ial f ! c5tre ( a volcanic cone does n effect m 9 ! way ( rais+ ! height ( ! crat]-walls4 ,b x mu/ be rememb]$ t1 9 ! case ( crat]s ( su* va/ area1 ! majority ( ! eject$ mat]ials mu/ fall back aga9 )9 its circumf]5ce4 ,by repeat$ ejections ^! mat]ials w at la/ be r$uc$ to su* an extreme /ate ( comm9ution t !y c be borne away by ! w9ds1 & spread ov] ! c\ntry to ! di/ance ( hundr$s or ?\s&s ( miles4 ,aft] great volcanic outbur/s enorm\s areas are ?us f\nd cov]$ ) f9e volcanic du/ to ! dep? ( _m in*es or feet4 ,illu/ration3 ,fig4 #gc4--,peak ( ,t5]iffe 9 ! ,can>y ,isl&s 7#ab1ahb ft471 surr\nd$ by great crat]-r+s4 ,sometimes1 z 9 ! case ( ! ,lago di ,bracciano1 ! eruptive =ces appe> to h entirely exhau/$ !mselves 9 ! prodigi\s outbur/ by :i* ! great crat] 0 produc$4 ,b 9 o!r cases1 z 9 t ( ! ,lago di ,bols5a1 ! eruptive action 0 resum$ at a lat] date1 & small tuff-cones 7 ?r[n up ^u ! floor ( ! crat]2 ^! n[ rise z isl&s above ! surface ( ! lake4 ,9 o!r cases1 aga91 ! eruptive action 0 resum$ aft] ! =mation ( ! great crat]-r+1 ) su* effect t bulky volcanic cones 7 built up 9 ! mid/ ( ! crat]-r+ :i* surr\nds !m l a va/ wall2 examples ( ?is are exhibit$ 9 ! ext9ct volcanoes ( ,rocca ,monf9a & ,monte ,albano4 ,"s ( ! gr&e/ volcanoes ( ! globe1 su* z ,t5]iffe 7fig4 #gc71 ! volcanoes ( ,mauritius & ,b\rbon 7figs4 #gd & #ge71 & _m o!rs t might be cit$1 are ?us f\nd to be surr\nd$ by va/ crat]-r+s4 ,vesuvius itself is surr\nd$ by ! crat]-r+ ( ,somma 7fig4 #gf74 ,illu/ration3 ,fig4 #gd4--,! volcano ( ,b\rbon1 ris+ 9 ! mid/ ( a crat]-r+ f\r miles 9 diamet]4 ,illu/ration3 ,fig4 #ge4--,! volcano ( ,b\rbon1 z se5 f ano!r po9t ( view1 ) ?ree conc5tric crat]-r+s encircl+ its base4 ,sid5ote3 ,,basaltic ,,cones ,,9 ,,tra*ytic ,,crat]-,,r+s4 ,?is =mation ( cone )9 crat]1 (t5 _m times repeat$1 is v *>act]i/ic ( volcanoes4 ,! crat]s m>k sudd5 & viol5t p>oxysmal outbur/s1 ! cones are ! result ( m mod]ate b long-cont9u$ ejection4 ,sometimes1 z at ,vesuvius 9 #agfg 7fig4 #ae1 p4 #he71 we f9d a ne/ ( crat]s & cones :i* v /rik+ly exemplifies ?is k9d ( action4 ,illu/ration3 ,fig4 #gf4--,vesuvius1 z se5 f ,sorr5to1 half encircl$ by ! crat]-r+ ( ,somma4 ,we %all po9t out1 h]eaft]1 t at mo/ volcanic c5tres ! ejection ( tra*ytic lavas prec$es t ( ! basaltic lavas4 ,n[ x is ^! tra*ytic lavas :i* pr9cipally give rise to ! =mation ( ! light lapilli ( :i* tuff-cones are =m$4 ,h5ce x is t we s frequ5tly f9d1 z 9 ! case ( ,vesuvius1 ,rocca-,monf9a1 & _m o!r volcanoes1 t a great crat]-r+1 l>gely compos$ ( tuffs1 encloses a cone built up ( m basic lavas4 ,9 fig4 #gg we h %[n by a s]ies ( outl9e sections ! v>i\s =ms assum$ by volcanoes 9 consequ5ce ( ! diff]5t k9ds ( eruptive action go+ on 9 !m3-- #a4 ,is an outl9e ( ,fusiyama1 an almo/ p]fect cone1 ) a small crat] at its summit4 ,! sides ( ?is volcano admirably illu/rate ! beautiful d\ble curves *>act]i/ic ( volcanic cones4 #b4 ,hv]fjall 9 ,icel&1 a volcanic cone ) a l>ge crat]1 rea*+ almo/ to its base4 #c4 ,! crat]-lake ( ,bracciano1 9 :i* ! area ( ! crat] is out ( all proportion to ! height ( ! crat]-walls4 #d4 ,rocca-,monf9a1 9 ,s\!rn ,italy1 a tuff-cone ( l>ge dim5sions1 9 ! mid/ ( :i* an &esitic lava-cone has be5 built up4 #e4 ,t5]iffe1 9 ! ,can>y ,isl&s1 9 :i* a p]fect volcanic cone has be5 built up 9 ! c5tre ( an encircl+ crat]-r+4 #f4 ,vulcano1 9 ! ,lip>i ,isl&s1 9 :i*1 by ! %ift+ ( ! c5tre ( volcanic activity along a l9e ( fissure1 a s]ies ( ov]lapp+ volcanic cones has be5 produc$4 ,illu/ration3 ,fig4 #gg4--,outl9es ( v>i\s ,volcanoes1 illu/rat+ ! diff]5t relations ( ! crat]s to cones4 ,sid5ote3 ,,subm>9e ,,volcanoes4 ,:ile speak+ ( ! v>ieties ( =m assum$ by volcanic cones & crat]s1 we mu/ n =get to notice ! effects :i* are produc$ by d5ud+ =ces ^u !m4 ,9 ! case ( subm>9e volcanoes1 l ! celebrat$ isl& call$ by ! ,engli% ,graham ,isle1 by ! ,fr5* ,isle ,julie1 & by ! ,g]mans ! ,insel ,f]d9&ez 7fig4 #gh71 :i* 0 ?r[n up (f ! coa/ ( ,sicily 9 #ahca1 x 0 evid5t t volcanic outbur/s tak+ place at "s dep? bel[ ! level ( ! sea gradually pil$ up a cone ( scori ) a crat] 9 its mid/4 ,by con/ant accessions to its mass1 ?is scoria-cone 0 ev5tually rais$ above ! sea-level1 b ! action ( ! waves ^u ! loose mat]ials soon de/roy$ ! crat]-walls & ev5tually r$uc$ ! isl& to a %oal4 ,x is evid5t t 9 all cases 9 :i* eruptions take place b5ea? ! sea-level1 & ! loose mat]ials are expos$ dur+ _! accumulation to ! beat+ ( ! sea-waves1 ! =m ( ! volcanic cone s produc$ w be greatly modifi$ by ! int]action ( ! two sets ( oppos$ causes1 ! eruptive =ces f bel[ & ! di/ributive action ( ! sea-waves4 ,illu/ration3 ,fig4 #gh4--;,isl& ?r[n up 9 ! ,m$it]ranean ,sea 9 ,july & ,augu/ #ahha4 7,! view 0 tak5 9 ! mon? ( ,septemb]1 aft] ! sides ( ! crat] _h be5 wa%$ away by ! waves47 ,crat]s :5 once =m$ are (t5 r5t across1 along ! l9e ( ! fissure above :i* !y are ?r[n up4 ,?us ! crat] ( ,vesuvius 0 9 #ahgb r5t completely asund] on "o side1 s t x 0 possible to climb ?r\gh ! fissure ?us produc$ & rea* ! bottom ( ! crat]4 ,/reams fl[+ d[n ! sides ( ! crat]1 & escap+ ?r\gh su* a r5t1 may 9 ! end greatly modify ! =m & disguise ! *>act]s ( a volcanic crat]4 ,( ?is k9d ( action we h a /rik+ example 9 ! ,val del ,bove ( ,etna4 ,volcanoes1 z we %all po9t out 9 ! sequel1 are aft] _! ext9ction frequ5tly subm]g$ b5ea? ! wat]s ( ! ocean4 ,! sea ent]+ ! crat]s1 eats back _! cliff-l sides & enl>ges _! areas4 ,su* d5ud$ wat]s are call$ 'cald]as1' ! *annels into !m 'b>rancos4' ,sometimes ! action ( ! waves ^u a p>tially subm]g$ volcano has l$ to ! cutt+ back ( its slopes into /eep cliffs1 at ! same "t t ! crat]-r+ is enl>g$4 ,9 su* cases we h left a m or less complete rocky r+1 compos$ ( alt]nat+ lavas & fragm5t>y mat]ials4 ,( su* a ru9$ crat]-r+1 ! ,isl& ( ,/4 ,paul 9 ! ,s\? ,atlantic af=ds an admirable example4 ,:5 ! action ( d5udation has gone /ill fur!r1 all ! lavas & tuffs compos+ ! cone may be completely remov$ & no?+ left b masses ( ! h>d & highly-cry/all9e rocks :i* h cool$ d[n sl[ly 9 ! he>t ( ! volcano4 ,an example ( ?is k9d is af=d$ to u by ,/4 ,kilda1 ! remote/ memb] ( ! ,briti% ,ar*ipelago4 ,b al?\gh ! majority ( volcanic crat]s are cle>ly =m$ by explosive action1 !re are "s crat]s1 l ^? ( ,kilauea 9 ,hawaii1 :i* probably owe _! orig9 to q a diff]5t set ( causes4 ,9 ?is case ! explosive action at ! v5t is b slight1 & ! crat]1 :i* is ( v irregul> =m1 appe>s to h orig9at$ 9 a fissure1 :i* has be5 sl[ly enl>g$ by ! liquid lavas encroa*+ ^u & eat+ away its sides4 ,su* crat]s z ^!1 h[ev]1 appe> to be comp>atively r>e4 ,besides ! great volcanic m\nta9s compos$ ( lava1 scori1 tuff & a%1 !re are o!r /ructures :i* are =m$ ar\nd volcanic v5ts ev5 :5 ^! d n eject molt5 rock-masses4 ,! wat] :i* issues 9 ^! cases ei!r z /eam or 9 a m or less highly heat$ condition frequ5tly c>ries mat]ials 9 susp5sion or solution1 & ^! sometimes accumulate 9 consid]able quantities ar\nd ! v5t4 ,sid5ote3 ,,=mation ,,( ,,mud-,,volcanoes4 ,:5 fissures are =m$ 9 ! mid/ ( loose argillace\s mat]ials1 su* z are frequ5tly produc$ by ! decomposition ( volcanic rocks1 ! wat]s :i* issue ?r\gh !m are sometimes s *>g$ ) muddy matt] t ?is accumulates to =m cones hav+ all ! g5]al *>act]s ( volcanic m\nta9s1 & :i* occasionally rise to ! height ( #bej feet4 ,! gases & vap\rs :i* issue f ^! 'mud-volcanoes' are ^? :i* are kn[n to be emitt$ f volcanic v5ts at :i* ! action go+ on is n v int5se4 ,daub5y & o!rs h sugge/$ t ^! mud-volcanoes may be ! result ( actions :i* h little or no analogy ) ^? :i* take place at ord9>y volcanic v5ts1 & t ! combu/ion ( subt]ranean b$s ( sulphur & simil> causes w\ld be q compet5t to _! production4 ,b inasmu* z ^! mud-volcanoes are almo/ always situat$ 9 regions 9 :i* ! m p[]ful volcanic action has only rec5tly di$ away1 & ! gases & vap\rs emitt$ by !m are v simil> 9 "* to ^? :i* issue f volcanoes1 !re does n appe> to be any good reason = d\bt+ t !y %\ld be class$ z truly volcanic ph5om5a4 ,mud-volcanoes are f\nd 9 ,nor!rn ,italy ne> ,mod5a1 9 ,sicily ne> ,girg5ti1 on ! %ores ( ! ,sea ( ,az( & ! ,caspian1 9 ,c5tral ,am]ica1 & 9 o!r p>ts ( ! globe4 ,! gas frequ5tly escapes f !m ) su* viol5ce t mud is ?r[n into ! air to ! height ( sev]al hundr$s ( feet4 ,sometimes ?is gas is inflammable1 consi/+ ( sulphurett$ hydrog51 hydrog51 or "s hydroc>bons1 & ^! gases occasionally take fire1 s t true flames issue f ^! mud-volcanoes4 ,9 o!r cases ! mud-volcanoes appe> to be =m$ by ei!r hot or cold spr+s conta9+ l>ge quantities ( susp5d$ mat]ials1 & ! liquid mud issues f ! v5t )\t any viol5t eruptive action4 ,illu/ration3 ,fig4 #gi4--,s9t]-cones surr\nd+ ! orifices ( ,geys]s4 #a4 ,bas9 ( ! ,great ,geys]1 ,icel&4 #b4 ,hot spr+ cone4 #c4 ,old ,fai?ful4 #d4 ,! ,great ,geys]4 #e4 ,lib]ty ,cap4 7#b1 #c1 #d & #e are 9 ! ,yell[/one ,p>k di/rict ( ! ,rocky ,m\nta9s47 ,sid5ote3 ,,=mation ,,( ,,s9t]-,,cones4 ,! soluble mat]ials :i* wat]s issu+ f volcanic v5ts deposit on _! sides are *iefly silica & c>bonate ( lime4 ,hot spr+s1 :e!r int]mitt5t or con/ant1 (t5 conta9 l>ge quantities ( silica 9 solution4 ,! solution ( ?is silica is effect$1 at ! mom5t ( its sep>ation f comb9ation ) ! alkali or alkal9e e>?s1 dur+ ! decomposition ( volcanic rocks1 & is fav\r$ by ! pres5ce ( alkal9e c>bonates 9 ! wat]1 & ! high temp]ature & ! pressure "u :i* x exi/s 9 ! subt]ranean regions4 ,:5 ! wat] rea*es ! surface &1 be+ reliev$ f pressure1 beg9s to cool d[n ! silica is deposit$4 ,by ?is deposit$ silica ! bas9s ar\nd ! geys]s ( ,icel& are =m$4 ,sometimes conical /ructures are built up ar\nd ! v5ts ( hot spr+s by ! deposition ( silica f _! wat]s4 ,examples ( ?is k9d ab\nd 9 ! ,national ,p>k ( ,colorado1 :]e !y h receiv$ fanciful names1 su* z ! ,beehive1 ,lib]ty ,gap1 c4 ,?is deposit$ silica is kn[n to geologi/s z s9t]4 ,! =ms ( "s ( ! /ructures :i* surr\nd ! orifices ( geys]s is %[n 9 fig4 #gi4 ,! ',lib]ty ,cap' is an ext9ct geys]-cone fifty feet high & tw5ty feet 9 diamet]4 ,hot & cold spr+s ris+ 9 volcanic regions are (t5 highly *>g$ ) c>bonic acid1 & 9 pass+ ?r\gh calc>e\s rocks dissolve l>ge quantities ( c>bonate ( lime4 ,^u exposure to ! atmosph]e1 ! free c>bonic acid escapes & ! c>bonate ( lime is deposit$ 9 ! =m kn[n z 'trav]t9e4' ,su* spr+s occur 9 great numb]s 9 _m volcanic regions4 ,9 ! ,auv]gne great rock-masses occur =m$ ( c>bonate ( lime deposit$ f a /ate ( solution & tak+ ! =m ( natural aqu$ucts & bridges4 ,9 ,c>lsbad ! num]\s hot spr+s h deposit$ masses ( pisolitic rock 7,/rudel/e97 :i* h fill$ up ! :ole bottom ( ! valley1 & ^u ^! deposits ! t[n itself is ma9ly built4 ,9 ,c5tral ,italy ! deposits ( trav]t9e =m$ by calc>e\s spr+s are ( enorm\s ext5t & ?ickness3 ,/4 ,pet]'s & all ! pr9cipal build+s ( ,rome be+ con/ruct$ ( ?is trav]t9e or ',tibur-/one4' ,sid5ote3 ,,=mation ,,( ,,s9t]-,,t]races4 ,:5 spr+s *>g$ ) silica or c>bonate ( lime rise ^u ! slope ( a hill compos$ ( loose volcanic mat]ials1 !y give rise to ! rem>kable /ructures kn[n z s9t]- & trav]t9e-t]races 7see fig4 #hj74 ,! wat] fl[+ d[nw>ds f ! v5t =ms a h>d deposit ^u ! l[] slope ( ! hill1 :ile ! cont9ual deposition ( solid mat]ials )9 ! v5t t5ds to *oke x up4 ,z a new v5t _c be =c$ by ! wat]s ?r\gh ! h>d rock =m$ bel[1 x is orig9at$ a little high] up4 ,?us ! site ( ! spr+ is gradually %ift$ f>!r & f>!r back into ! hill4 ,z deposition takes place along ! surfaces ov] :i* ?is wat] fl[s1 t]races are built up enclos+ bas9s4 ,( /ructures ( ?is k9d we h rem>kable examples 9 ! s9t]-t]races ( ,rotomahana 9 ,new ,zeal& & ! trav]t9e-t]races ( ! ,g>d9]'s ,riv] 9 ! ,yell[/one ,p>k di/rict ( ! ,rocky ,m\nta9s4 ,illu/ration3 ,fig4 #hj4--;,diagram illu/rat+ ! mode ( =mation ( ,trav]t9e & ,s9t] ,t]races on ! sides ( a hill ( tuff4 ,,*apt] ,,vii4 ,,! ,,succession ,,( ,,op]ations ,,tak+ ,,place ,,at ,,volcanic ,,c5tres4 ,t a volcanic v5t1 :5 once e/abli%$1 may display int5se activity dur+ enorm\s p]iods ( "t1 !re _c be ! smalle/ reason = d\bt+2 = ! accumulation ( mat]ials ar\nd "s exi/+ volcanic c5tres mu/ c]ta9ly h be5 go+ on dur+ _m ?\s&s1 p]haps millions1 ( ye>s4 ,to u1 ^: p]iods ( obs]vation are s circumscrib$1 x may !re=e at fir/ sight appe> a hopeless task to trace ! 'life-hi/ory ( a volcano1' to discov] ! /ages ( its developm5t1 & to indicate ! v>i\s episodes :i* h occurr$ dur+ ! long p]iods x has be5 9 exi/5ce4 ,b :5 x is rememb]$ t we h ! opportunity ( /udy+ & comp>+ hundr$s ( su* volcanoes1 exhibit+ e v>y+ phase ( _! developm5t1 we %all see t su* an attempt is by no means s unpromis+ z x at fir/ sight appe>s to be4 ,9 ! pres5t *apt]1 we %all give an acc\nt ( ! results :i* h already be5 obta9$ by inquiries direct$ to ?is object4 ,sid5ote3 ,,cycles ,,( ,,volcanic ,,ph5om5a4 ,!re is n ! smalle/ room = d\bt t dur+ ! pa/ hi/ory ( our globe1 exhibitions ( subt]ranean en]gy h occurr$ at _m diff]5t p>ts ( its surface4 ,!re is fur!r evid5ce t at ! sev]al sites :]e ^! displays ( ! volcanic =ces h tak5 place1 ! succession ( ! outbur/s has run ?r\gh a regul> cycle1 gradually increas+ 9 int5sity to a maximum1 & !n z gradually dy+ away4 ,a little consid]ation w %[ t ! fir/ portion ( ?is cycle ( ev5ts is ! "o :i* x is mo/ difficult to exam9e & /udy4 ,! products ( ! e>li] & feeble displays ( volcanic activity1 at any p>ticul> c5tre1 are liable to be de/roy$1 or mask$1 dur+ ! ejection ( ov]:elm+ masses ( mat]ials 9 ! lat] /ages ( its m matur$ en]gy4 ,t ! feeble displays ( volcanic =ce n[ exhibit$ 9 "s localities w gradually increase 9 int5sity 9 ! future1 & ev5tually rea* ! gr&e/ /age ( developm5t1 !re c be no reason = d\bt+4 ,b1 un=tunately1 we are q unable to discrim9ate ^! feeble manife/ations1 :i* are ! embryonic /ages 9 ! developm5t ( gr& exhibitions ( ! volcanic =ces1 f slight outbur/s :i* die away & make no f>!r sign4 ,f :at has be5 prov$ conc]n+ ! true nature ( volcanic action1 h[ev]1 x is c]ta9 t ! fir/ /ep t[>ds ! exhibition ( su* action1 at any p>ticul> locality1 mu/ be ! production ( an ap]ture 9 ! e>?'s cru/4 ,only by means ( su* an ap]ture c ! vap\rs1 gases1 & rocky mat]ials rea* ! surface1 & give rise to ! ph5om5a !re display$4 ,!re is reason to believe t all su* ap]tures are really ( ! nature ( fissures1 or cracks1 :i* h be5 op5$ ?r\gh ! sup]jac5t /rata by ! ef=ts ( ! repress$ subt]ranean =ces4 ,"s rec5t writ]s h1 x is true1 endeav\r$ to draw a di/9ction betwe5 :at !y call 'fissure-eruptions1' & eruptions tak+ place f volcanic cones4 ,b all volcanic outbur/s are truly 'fissure-eruptions'--! subt]ranean mat]ials f9d+ _! way to ! surface ?r\gh great cracks1 :i*1 9 a m or less v]tical position1 trav]se ! ov]ly+ rock-masses4 ,x is true t 9 _m cases portions ( ^! cracks soon get *ok$ up1 :ile o!r portions become wid5$1 & ! volcanic en]gy is conc5trat$ at su* spots4 ,?us ! mat]ials eject$ f ^! fissures are usually emitt$ 9 greate/ quantities at "o or m po9ts along ! fissure1 & a s+le great volcanic v5t1 or a r[ ( small] v5ts1 is e/abli%$ ^u ! l9e at :i* ! fissure rea*es ! surface4 ,we h se5 t ! am\nt ( explosive action tak+ place at diff]5t volcanic v5ts v>ies accord+ to ! proportion ( imprison$ wat] conta9$ 9 ! lava4 ,9 ! cases :]e !re is mu* explosive action1 va/ accumulations ( scori1 lapilli1 & du/ take place1 & cones ( great size are built up2 b 9 ^? cases :]e ! explosive action is small ! lavas fl[ quietly f ! v5t1 & only small scori-cones are ?r[n up1 ^! be+ probably soon swept away by ! lava-curr5ts !mselves or by d5ud+ ag5cies4 ,b bo? k9ds ( eruption h equal claims to be call$ 'fissure-eruptions4' ,sid5ote3 ,,=mation ,,( ,,volcanic ,,fissures4 ,9 ! expansive =ce ( great masses ( imprison$ vap\r1 we h a compet5t cause = ! production ( ! fissures ?r\gh :i* volcanic outbur/s take place4 ,su* fissures are f\nd trav]s+ ! rocks ly+ above volcanic foci1 & (t5 ext5d+ to di/ances ( _m miles1 or ev5 hundr$s ( miles1 f ! c5tres ( activity4 ,"s ( ^! cracks are f\nd to be inject$ ) fus$ mat]ials f bel[1 o!rs h be5 m or less completely fill$ ) v>i\s m9]als t h be5 volatiliz$1 or c>ri$ by sup]heat$ wat]s f ! deep] regions ( ! e>?'s cru/4 ,t _m ( ! cracks ?us produc$ 9 ! sup]jac5t rocks1 by ! heav+ =ces ( imprison$ vap\r seek+ to escape1 nev] rea*$ ! surface1 we h suffici5t pro( 9 _m m9+ regions4 ,if we n[ transf] our att5tion f ! deep] portions ( ! e>?'s cru/ to ! surface1 we c well und]/& h[ ! attempts ( ! imprison$ vap\rs to =ce a passage = !mselves ?r\gh ! solid rock-masses w\ld lead to %ocks & j>s among ! latt]4 ,ea* ( ^! %ocks or j>s w\ld give rise1 9 ! surr\nd+ portions ( ! e>?'s cru/1 to ^? vibrations :i* we "k z e>?quakes4 ,! close connection betwe5 mo/ e>?quakes & volcanic ph5om5a is a fact t does n admit ( ! smalle/ d\bt2 & ?\gh x w\ld be ra% to def9e all e>?quakes z 'uncomplet$ ef=ts to e/abli% a volcano1' yet1 9 ! ef=ts ( ! repress$ subt]ranean =ces to f9d a v5t by ! production ( fissures 9 ! ov]ly+ rock-masses1 we h a cause compet5t to ! production ( ^? %ocks :i* are transmitt$ to su* enorm\s di/ances z waves ( ela/ic compression4 ,we h se5 t ! production ( ! fissure ^u :i* ! small volcano ( ,monte ,nuovo 0 ?r[n up 0 prec$$ by a succession ( e>?quakes1 :i* = a p]iod ( ov] two ye>s t]rifi$ ! inhabitants ( ! di/rict1 & might h w>n$ !m ( ! com+ ev5t4 ,9 ! same mann]1 d\btless1 ! p]iod be=e ! appe>ance ( volcanic ph5om5a 9 a new area w\ld be m>k$ by p[]ful subt]ranean di/urbances )9 x1 due to ! ef=ts ( ! imprison$ vap\rs to =ce = !mselves a *annel to ! surface4 ,sid5ote3 ,,nature ,,( ,,fir/ ,,ejections ,,f ,,fissures4 ,9 ! case ( ,monte ,nuovo1 we h se5 t ! fissure1 :5 produc$1 emitt$ wat]--at fir/ 9 a cold1 !n 9 a boil+ condition--&1 ev5tually1 /eam & scori4 ,x is probable t ?r\gh ! fir/ cracks :i* rea*$ ! surface1 dur+ ! heav+ ( ! subt]ranean =ces1 wat]1 *>g$ ) c>bonic acid1 fl[$ abundantly1 & t ^! cold spr+s1 *>g$ ) c>bonic acid & c>bonate ( lime1 w\ld be succe$$ by o!rs :i* 7 hot & conta9$ silica 9 solution4 ,9 ,hung>y1 ! ,we/]n ,isles ( ,scotl&1 & _m o!r volcanic di/ricts1 we f9d abundant evid5ce t1 be=e ! eruption ( lavas 9 ! area1 great masses ( trav]t9e & silice\s s9t] 7 =m$ by ! action ( cold & hot spr+s4 ,z ! volcanic action became m int5se by ! m p]fect op5+ ( ! fissures1 ! evolution ( c>bonic add gas w\ld be succe$$ by ! appe>ance ( sulphur\s acid1 sulphurett$ hydrog51 boracic acid1 & hydro*loric acid1 :i* rec5t /udies h %[n to be successively emitt$ f volcanic v5ts z ! temp]ature )9 !m rises4 ,at la/ lava or molt5 rock becomes visible )9 ! fissures1 & ! ejection ( ! fro?y masses--scori1 pumice1 lapilli & du/--comm5ces1 & ?is is sometimes succe$$ by ! outfl[ ( curr5ts ( lava4 ,t volcanoes orig9ate ^u l9es ( fissure 9 ! e>?'s cru/ we h ! mo/ conv9c+ pro(s4 ,n only h su* fissures be5 se5 9 actual c\rse ( =mation at ,vesuvius1 ,etna1 & o!r active volcanoes1 b a /udy ( ! volcanoes dissect$ by d5udation af=ds ! mo/ conv9c+ evid5ce ( ! same fact4 ,! rem>kable l9e> arrangem5t se5 9 gr\ps ( volcanoes1 :i* is conspicu\s to ! mo/ sup]ficial obs]v]1 confirms ?is conclusion4 ,illu/ration3 ,fig4 #ha4--,map ( ! volcanic gr\p ( ! ,lip>i ,isl&s1 illu/rat+ ! position ( ! l9es ( fissure on :i* ! volcanoes h be5 built up4 ,sid5ote3 ,,%ift+ ,,( ,,v5ts ,,along ,,fissures4 ,we h describ$ ! action go+ on at ,/romboli z typical ( t :i* occurs at all volcanic v5ts4 ,/romboli is1 h[ev]1 "o among a gr\p ( isl&s all ( :i* are entirely ( volcanic orig94 ,! volcanoes ( ?is gr\p ( isl&s1 ! olian or ,lip>i ,isl&s1 are arrang$ along a s]ies ( l9es :i* d\btless m>k fissures 9 ! e>?'s cru/4 ,^! fissures1 z w be se5 by ! accompany+ map 7fig4 #ha71 radiate f a c5tre at :i* we h pro(s ( ! =m] exi/5ce ( a volcano ( enorm\s dim5sions4 ,x is a v int]e/+ fact1 :i* ! /udies ( ,pr(4 ,suess h e/abli%$1 t ! e>?quakes :i* h s (t5 desolat$ ,calabria appe> to h orig9at$ imm$iately b5ea? ?is great c5tre ( volcanic activity4 ,illu/ration3 ,fig4 #hb4--,! ,puy de ,p>i\ 9 ! ,auv]gne1 illu/rat+ ! %ift+ ( ! c5tre ( eruption along a l9e ( fissures4 ,:5 two volcanic cones are ?r[n up on ! same l9e ( fissure1 _! full developm5t is int]f]$ )1 & irregul>ities 9 _! =m & *>act]s are ! consequ5ce4 ,9 ! plan 7fig4 #hb7 & ! section 7fig4 #hc7 an example is giv5 ( ! results ( su* a %ift+ ( ! c5tre ( eruption along a l9e ( fissure4 ,by ! second outbur/1 "o-half ( ! fir/-=m$ cone has be5 remov$1 & ! second-=m$ ov]laps ! fir/4 ,illu/ration3 ,fig4 #hc4--;,ideal section ( ! ,puy de ,p>i\4 ,sometimes a numb] ( scoria- or tuff-cones are ?r[n up 9 su* close proximity to "o ano!r along a l9e ( fissure1 t !y m]ge into a long irregul> heap on ! summit ( :i* a numb] ( di/9ct crat]s c be trac$4 ,an example ( ?is k9d 0 furni%$ by ! l9e ( scoria-cones =m$ above ! fissure :i* op5$ on ! flanks ( ,etna 9 #ahfe 7see fig4 #hd74 ,illu/ration3 ,fig4 #hd4--;,fissure =m$ on ! flanks ( ,etna dur+ ! eruption ( #ahfe4 a4 ,monte ,frum5to1 an old p>asitic cone4 b4 ,l9e ( fissure4 c1 c1 c4 ,new scoria-cones ?r[n up on l9e ( fissure4 d4 ,lava f same4 ,illu/ration3 ,fig4 #he4--,plan ( ! ,isl& ( ,vulcano1 bas$ on ! map ( ! ,italian ,gov]nm5t4 ,sid5ote3 ,,%ift+ ,,( ,,eruptions ,,along ,,fissures4 ,ev5 9 ! case ( great composite cones1 h[ev]1 we sometimes f9d pro(s ( ! c5tre ( eruption hav+ %ift$ its place along ! l9e ( fissure4 ,no bett] example ( ?is k9d c\ld possibly be adduc$ ?an t ( ! ,isl& ( ,vulcano1 ) ! p59sula ( ,vulcanello1 :i* is jo9$ to x by a n>r[ i/hmus 7see ! map1 fig4 #ha1 p #aib74 ,9 fig4 #he we h giv5 an enl>g$ plan ( ?is isl& :i* w make its peculi> /ructure m intelligible 7see also ! section giv5 9 fig4 #gg1 ,no4 #f1 fac+ p4 #agh74 ,! s\?-ea/]n "p ( ! isl& consi/s ( f\r crat]-r+s1 "o half ( ea* ( ,:i* has be5 successively de/roy$1 ?r\gh ! %ift+ ( ! c5tre ( eruption t[>ds ! nor?-we/1 along ! great l9e ( fissure %[n 9 ! g5]al map 7fig4 #ha74 ,! la/ =m$ ( ^! f\r crat]-r+s is ! "o :i* is n[ mo/ complete1 & culm9ates 9 ,monte ,s>ac5o 7#aeha ft471 a 9 ! plan1 ! highe/ po9t 9 ! isl&4 ,! old] crat]-r+s h be5 9 "p remov$ by ! inroads ( ! wat]s ( ! ,m$it]ranean on ! %ores ( ! isl&4 ,9 ! c5tre ( ! great crat]1 b1 :i* we h j describ$1 rises ! pres5t active cone ( ,vulcano1 #a1bff feet high1 & hav+ a crat]1 c1 ab\t #fjj y>ds 9 diamet] & m ?an #ejj feet 9 dep?4 ,f ?is cone1 a great /ream ( obsidian1 e1 fl[$ 9 ! ye> #agge1 & a small crat]1 d1 ! ,fossa ,anti*a1 has be5 op5$ 9 ! side ( ! cone4 ,! cont9uation ( ! same l9e ( fissure is indicat$ by a ru9$ tuff-cone1 f1 kn[n z ! ,f>aglione1 & ! ?ree scoria-cones ( ,vulcanello1 g1 h1 :i* h be5 ?r[n up s close to "o ano!r z to h _! l[] portions m]g$ 9 "o common mass1 z %[n 9 fig4 #hf4 ,sid5ote3 ,,sy/ems ,,( ,,volcanic ,,fissures4 ,ev5 9 volcanoes ( ! l>ge/ dim5sions we sometimes f9d pro(s ( ! c5tre ( eruption hav+ %ift$ along ! l9e ( fissure4 ,lyell %[$ t su* a *ange 9 ! position ( ! c5tral axis ( ! volcano _h tak5 place 9 ,etna1 & ! same ph5om5on is exhibit$ 9 ! cle>e/ mann]' by "s ( ! anci5t volcanoes ( ! ,inn] ,hebrides1 :i* h be5 dissect$ by ! d5ud+ =ces4 ,illu/ration3 ,fig4 #hf4--,vulcanello1 ) its ?ree crat]s4 a4 ,! mo/ rec5tly-=m$ & p]fect crat]1 b & c4 ,old] crat]s1 ! walls ( :i* h be5 p>tly remov$ by d5udation1 e4 ,lava-curr5ts proce$+ f b4 ,! section expos$ 9 ! cliff at d is repres5t$ 9 fig4 #ce1 p4 #aaf4 ,9 ! case ( ! ,lip>i ,isl&s1 ! fissures along :i* ! volcanic m\nta9s h be5 ?r[n up radiate f a common c5tre1 & a simil> arrangem5t c be trac$ 9 _m volcanic regions1 especially ^? 9 :i* a great c5tral volcano has exi/$4 ,9 o!r cases1 h[ev]1 z 9 ! ,campi ,phlegri1 ! volcanic v5ts appe> to be =m$ along l9es :i* assume a p>allel arrangem5t1 & ?is d\btless m>ks ! relative position ( ! orig9al fissures produc$ 9 ! e>?'s cru/ :5 ^! volcanoes 7 =m$4 ,9 "s o!r cases we f9d evid5ces ( ! exi/5ce ( a pr9cipal fissure f ! sides ( :i* small] cracks orig9at$4 ,^! ?ree k9ds ( arrangem5ts ( volcano-produc+ fissures are equally well illu/rat$ :5 we /udy ^? d5ud$ di/ricts1 9 :i*1 z we h se51 ! gr\nd-plans ( volcanic /ructures are reveal$ to our view4 ,!re is n[ good gr\nd = believ+ t 9 volcanic v5ts1 at :i* long-cont9u$ eruptive action takes place1 ! lavas ( diff]5t *emical composition make _! appe>ance 9 some?+ l a def9ite ord]4 ,x _h be5 rem>k$ by ,scrope & o!r geologi/s at ! beg9n+ ( ! pres5t c5tury1 t 9 _m volcanic areas ! acid or tra*ytic lavas 7 erupt$ be=e ! basic or basaltic4 ,von ,ri*?(51 by 8 /udies 9 ,hung>y & ! volcanic di/ricts ( ! ,rocky ,m\nta9s1 has be5 able to enunciate a law gov]n+ ! natural ord] ( succession ( volcanic products2 & al?\gh "s exception to ?is law may be m5tion$1 x is f\nd to hold good = _m o!r di/ricts ?an ^? 9 :i* x 0 fir/ det]m9$4 ,9 a great numb] ( cases x has be5 f\nd t ! fir/ erupt$ rocks 9 a volcanic di/rict are ^? ( int]m$iate composition :i* are kn[n z &esites4 ,^! &esites1 :i* are especially *>act]is$ by ! nature ( _! felsp>1 sometimes conta9 free qu>tz & are !n kn[n z qu>tz-&esites or dacites1 f _! abundance 9 ,transylvania1 ! old ,roman prov9ce ( ,dacia4 ,sid5ote3 ,,ord] ,,( ,,eruption ,,( ,,volcanic ,,products4 ,von ,ri*?(5 sugge/s t ano!r class ( volcanic rocks1 to :i* he gives ! "n ( 'propylites1' 7 9 e case erupt$ be=e ! &esites1 & 9 support ( 8 views adduces ! fact t 9 _m in/ances propylites are f\nd und]ly+ &esites4 ,b ! propylites are1 9 *emical composition1 id5tical ) ! &esites1 & l !m pres5t "s v>ieties 9 :i* qu>tz occurs1 & o!rs 9 :i* t m9]al is abs5t4 ,9 _! microscopic *>act]s ! propylites diff] f ! &esites & dacites only 9 ! fact t ! =m] are m p]fectly cry/all9e 9 /ructure1 be+ inde$ 9 _m cases q undi/+ui%able f ! diorites or ! plutonic repres5tatives ( ! &esites4 ,! propylites also conta9 liquid cavities1 :i* ! &esites & dacites z a rule d n1 & ! =m] class ( rocks1 z ,pr(4 ,szabo well po9ts out1 are usually mu* alt]$ by ! passage ( sulphur\s & o!r vap\rs1 9 consequ5ce ( :i* !y frequ5tly conta9 valuable metallic ores4 ,! extrusion ( ^! &esitic lavas is sometimes accompani$1 & sometimes prec$$ or foll[$1 by eruptions ( tra*ytic lavas--t is1 ( lavas ( int]m$iate composition :i* h a diff]5t k9d ( felsp> f t prevail+ 9 ! &esites4 ,9 ! f9al /ages ( ! eruptive action 9 mo/ volcanic di/ricts ! lavas p\r$ =? belong to ! classes ( ! rhyolitic or acid1 & ! basaltic or basic lavas4 ,^! facts are admirably illu/rat$ 9 ! case ( ! volcanic di/rict ( ! ,lip>i ,isl&s1 to :i* we h _h su* frequ5t occasion to ref]4 ,! great c5tral volcano ( ?is di/rict1 :i* n[ 9 a ru9$ condition con/itutes a numb] ( small islets 7see ! map1 fig4 #ha1 p4 #aib71 is compos$ ( &esitic lavas4 ,! o!r great volcanoes ?r[n up along ! ?ree radiat+ l9es ( fissure are compos$ ( &esitic & tra*ytic rocks4 ,b all ! m rec5t ejections ( ! volcanoes ( ! di/rict h consi/$ ei!r ( rhyolites1 z 9 ,lip>i & ,vulcano1 or ( basalts1 z 9 ,/romboli & ,vulcanello4 ,von ,ri*?(5 & ! geologi/s :o mo/ /rongly ma9ta9 ! g5]alisations :i* he has made conc]n+ ! ord] ( appe>ance ( volcanic products1 g mu* f>!r ?an we h v5tur$ to d1 & insi/ t 9 all volcanic di/ricts a con/ant & unv>y+ succession ( diff]5t k9ds ( lavas c be made out4 ,x appe>s to u1 h[ev]1 t ! exceptions to ! law1 z ?us precisely /at$1 are s num]\s z to entirely de/roy its value4 ,! g5]alisation t 9 mo/ volcanic di/ricts ! fir/ eject$ lavas belong to ! int]m$iate gr\p ( ! &esites & tra*ytes1 & t subsequ5tly ! acid rhyolites & ! basic basalts made _! appe>ance1 is "o t appe>s to admit ( no d\bt1 & is f\nd to hold good 9 ne>ly all ! volcanic regions ( ! globe :i* h be5 att5tively /udi$4 ,! ,t]ti>y volcanic rocks ( our own c\ntry1 ^? ( ,nor? ,g]many1 ,hung>y1 ! ,euganean ,hills1 ! ,lip>i ,isl&s1 & _m o!r di/ricts 9 ! ,old ,_w1 toge!r ) ! widespread volcanic rocks ( ! ,rocky ,m\nta9s 9 ! ,new ,_w1 all seem to con=m to ?is g5]al rule4 ,sid5ote3 ,,!ory ,,( ,,volcanic ,,magmas4 ,9 connection ) ?is subject1 x may be well to ref] to ! ideas on ! composition ( volcanic rocks :i* 7 enunciat$ by ,buns51 & ! !oretic views bas$ on !m by ,duro*]4 ,buns5 ju/ly po9t$ out t all volcanic rocks might be reg>d$ z mixtures 9 v>y+ proportions ( two typical k9ds ( mat]ials1 :i* he nam$ ! 'normal tra*ytic' & ! 'normal pyrox5ic' elem5ts respectively4 ,! fir/ ( ^! corresponds v closely 9 composition ) ! acid volcanic rocks or rhyolites1 & ! second ) ! basic volcanic rocks or basalts4 ,duro*] po9t$ out t if quantities ( ^! diff]5t mat]ials exi/$ 9 admixture1 ! high] specific gravity ( ! basic elem5t w\ld cause x gradually to s9k to ! bottom1 :ile ! acid elem5t w\ld rise to ! top4 ,c>ry+ out ?is idea /ill fur!r1 he prop\nd$ ! !ory t b5ea? ! e>?'s solid cru/ !re exi/ two magmas1 ! upp] consi/+ ( light acid mat]ials1 ! l[] ( heavy basic ones2 & he suppos$ t by ! v>y+ int5sity ( ! volcanic =ces we may h sometimes "o or ! o!r magma erupt$ & sometimes v>y+ mixtures ( ! two4 ,! /udy ( volcanic rocks 9 rec5t ye>s has n l5t mu* support to ! !oretic views ( ,duro*] conc]n+ ! exi/5ce ( two univ]sal magmas b5ea? ! e>?'s cru/2 & !re are n a few facts :i* seem q irreconcilable ) su* a !ory4 ,?us we f9d evid5ce t 9 ! adjac5t volcanic di/ricts ( ,hung>y & ,bohemia1 volcanic action 0 go+ on dur+ ! :ole ( ! latt] "p ( ! ,t]ti>y p]iod4 ,b ! products ( ! contemporane\s volcanic outbur/s 9 adjac5t areas 7 z diff]5t 9 "* z c well be imag9$4 ,! volcanic rocks all ov] ,hung>y pres5t a /rong family lik5ess2 ! fir/ erupt$ 7 tra*ytes1 !n foll[$ &esites & dacites 9 great abundance1 & la/ly rhyolites & basalts conta9+ felsp>4 ,b 9 ,bohemia1 ! lavas p\r$ out f ! volcanoes dur+ ! same p]iod 7 fir/ly phonolites & !n basalts conta9+ nephel9e & leucite4 ,x is sc>cely possible to imag9e t su* v diff]5t classes ( lavas c\ld h be5 p\r$ out f v5ts :i* 7 9 communication ) ! same res]voirs ( igne\s rock1 & we are driv5 to conclude t ! ,hung>ian & ,bohemian volcanoes 7 suppli$ f diff]5t s\rces4 ,sid5ote3 ,,sep>ation ,,( ,,lavas ,,9 ,,res]voirs4 ,b ! und\bt$ fact t 9 s _m volcanic regions ! eruption ( &esitic & tra*ytic rocks1 :i* are ( int]m$iate composition1 is foll[$ by ! appe>ance ( ! diff]5tiat$ products1 rhyolite & basalt1 :i* are ( acid & basic composition respectively1 l5ds n a little support to ! view t "u ea* volcanic di/rict a res]voir ( m or less completely molt5 rock exi/s1 & t 9 ^! res]voirs v>i\s *anges take place dur+ ! long p]iods ( igne\s activity4 ,dur+ ! e>li] p]iod ( eruption ! heavi] & light] elem5ts ( ! cont5ts ( ^! subt]ranean res]voirs appe> to be m+l$ toge!r2 b 9 ! lat] /ages ( ! volcanic hi/ory ( ! di/rict1 ! light] or acid elem5ts rise to ! top1 & ! heavi] or basic s9k to ! bottom1 & we h sep>ate eruptions ( rhyolite & basalt4 ,we ev5 f9d "s traces ( ?is action be+ c>ri$ /ill fur!r4 ,among ! basalts eject$ f ! volcanoes ( ,nor!rn ,g]many1 ,bohemia1 ,/yria1 ,auv]gne1 & _m o!r regions1 we n unfrequ5tly f9d r\nd$ masses consi/+ ( oliv9e1 en/atite1 augite1 & o!r heavi] con/itu5ts ( ! rock4 ,^! (t5 =m ! c5tre ( volcanic bombs1 & are n improbably portions ( a d5se mass :i* may h sunk to ! bottom ( ! res]voirs ( basaltic mat]ials4 ,9 consequ5ce ( ! circum/ance t ! eruption ( lavas ( int]m$iate composition usually prec$es t ( o!r v>ieties1 we usually f9d ! c5tral & old] portions ( great volcanoes to be =m$ ( &esites1 tra*ytes1 or phonolites1 :ile ! out] & new] portions ( ! mass are made up ( acid or basic lavas4 ,?is is /rik+ly exemplifi$ 9 ! great volcanoes ( ! ,auv]gne & ! ,we/]n ,isles ( ,scotl&1 9 all ( :i* we f9d t great m\nta9 masses h1 9 ! fir/ in/ance1 be5 built up by extrusions ( lava ( ! int]m$iate types1 & t ?r\gh ?is c5tral core fissures h be5 op5$ convey+ basic lavas to ! surface4 ,f ^! fissures great numb]s ( basaltic lava-/reams h issu$1 greatly increas+ ! height & bulk ( ! volcanic cones & delug+ ! c\ntry all ar\nd4 ,! lavas ( int]m$iate composition--! &esites1 tra*ytes1 & phonolites--possess1 z we h already se51 b v imp]fect liquidity z !y fl[ f ! volcanic v5ts4 ,h5ce we f9d !m ei!r accumulat+ 9 great dome-%ap$ masses above ! v5t or =m+ lava-/reams :i* are ( great bulk & ?ickness1 b d n fl[ f> f ! orifices :5ce !y issue4 ,! m fusible basaltic lavas1 on ! o!r h&1 spread out ev5ly on issu+ f a v5t1 & sometimes fl[ to ! di/ance ( _m miles f x4 ,?is diff]5ce 9 ! behavi\r ( ! int]m$iate & basic lavas is admirably illu/rat$ 9 ! volcanic di/ricts ( ! ,auv]gne & ! ,we/]n ,isles ( ,scotl&4 ,9 o!r cases1 l ,vesuvius1 we f9d t great volcanic cones ( tra*ytic tuff h be5 built up1 & t ^! masses ( fragm5t>y tra*ytic mat]ials h be5 surr\nd$ & enclos$ by ! ejection1 at a lat] date1 ( great outbur/s ( basaltic lavas4 ,9 /ill o!r cases1 ( :i* ,rocca ,monf9a 9 ,s\!rn ,italy con/itutes an excell5t example1 we f9d t a great crat]-r+ ( tra*ytic tuffs has be5 =m$ 9 ! fir/ in/ance1 & 9 ! mid/ ( ?is a cone1 compos$ ( m basic mat]ials1 has be5 ?r[n up4 ,sid5ote3 ,,exceptions ,,to ,,! ,,g5]al ,,law4 ,9 all ^! volcanoes we see ! t5d5cy t[>ds ! eruption ( int]m$iate lavas 9 ! fir/ in/ance1 & ( basaltic & acid lavas at a lat] date4 ,valuable1 h[ev]1 z are ! e>ly g5]alisations ( ,scrope1 & ! m precise law enunciat$ by ,von ,ri*?(5 conc]n+ ! 'natural ord] ( succession ( volcanic products1' we mu/ n =get t !re are to be f\nd a consid]able numb] ( exceptions to !m4 ,!re are "s volcanic c5tres f :i* only "o k9d ( lava has be5 emitt$1 & ?is may be ei!r acid1 basic1 or int]m$iate 9 composition2 & on ! o!r h&1 !re are di/ricts 9 :i* v>i\s k9ds ( lava h be5 eject$ f ! same v5ts )9 a %ort p]iod ( "t1 9 su* a way z to defy e attempt to make out any?+ l a law z to ! ord] ( _! appe>ance4 ,nev]!less ! rules :i* we h indicat$ appe> to hold good 9 s great a numb] ( cases t !y are well wor?y ( be+ rememb]$1 & may s]ve z a basis on :i* we may reason conc]n+ ! nature ( ! action go+ on b5ea? volcanic v5ts4 ,f ! /udy ( ! ext]nal appe>ances ( volcanic m\nta9s1 comb9$ ) inve/igations ( ^? :i* h be5 dissect$ by d5udation1 we are able to picture to our m9ds ! s]ies ( actions by :i* ! great volcanic m\nta9s ( ! globe h be5 sl[ly & gradually built up4 ,9 ! fir/ in/ance ! eruptions appe> to h tak5 place at sev]al po9ts along a l9e ( fissure1 b gradually all ( ^! w\ld become *ok$ up except "o :i* became ! c5tre ( habitual eruption4 ,f ?is op5+1 ejections1 fir/ly ( lavas ( int]m$iate composition1 & aft]w>ds ( basic mat]ials1 w\ld take place1 until a volcano ( consid]able dim5sions 0 built up ar\nd x4 ,b at la/ a po9t w\ld be rea*$ 9 ! pil+ up ( ?is cone1 :5 ! volcanic =ces bel[ w\ld be inadequate to ! "w ( rais+ ! liquid lava ?r\gh ! :ole l5g? ( ! cont9ually upw>d-gr[+ tube ( ! volcano4 ,"u ^! circum/ances ! expansive =ce ( ! imprison$ /eam w\ld f9d x easi] to r5d asund] ! sides ( ! volcanic cone ?an to =ce ! liquid mat]ial to ! summit ( ! m\nta94 ,if ^! fissures rea*$ ! surface explosive action w\ld take place1 9 consequ5ce ( ! escape ( /eam f ! gl[+ mass1 & scoria-1 tuff-1 & lava-cones w\ld be =m$ above ! fissure4 ,9 ?is way1 z we h already po9t$ out1 ! num]\s 'p>asitic cones' :i* usually ab\nd on ! flanks ( ! great] volcanic m\nta9s h be5 =m$4 ,! extrusion ( ^! masses ( scori & lava on ! flanks ( ! m\nta9 t5ds1 n only to increase ! bulk ( ! mass1 b to /r5g!n & =tify ! sides4 ,= by ! p[]ful expansive =ce at "w bel[1 e weak place 9 ! cone is discov]$ & a fissure produc$ !re2 b by ! extrusion ( mat]ial at ?is fissure1 & /ill m by ! consolidation ( ! lava 9 ! fissure1 ! weak place is conv]t$ into "o ( exceptional /r5g?4 ,sid5ote3 ,,intrusive ,,masses ,,b5ea? ,,volcanoes4 ,z ! sides ( ! cone are ?us cont9ually repair$ & /r5g!n$ !y are r5d]$ m capable ( )/&+ ! heav+ =ces act+ f bel[1 & ^! =ces c !n only f9d v5t = !mselves by aga9 rais+ ! liquefi$ lava to ! c5tral orifice ( ! m\nta94 ,_m volcanoes1 l ,etna1 exhibit ?is alt]nation ( eruptive action f ! crat] at ! summit ( ! m\nta91 & f fissures op5$ ^u its flanks1 ! =m] t5d+ to raise ! height ( ! volcanic pile1 ! latt] to increase its bulk4 ,b at la/ a /age w be rea*$ :5 ! volcanic =ces are no long] able ei!r to raise ! lava up ! long column ( ! c5tral v5t on ! "o h&1 or to r5d asund] ! /rongly-built & well-compact$ flanks ( ! m\nta9 on ! o!r4 ,x is probably "u ^! conditions1 = ! mo/ "p1 t ! lavas f9d _! way betwe5 ! masses ( surr\nd+ /rata & =ce !m asund] 9 ! way t we h already describ$4 ,9 ! case ( ! m fluid basaltic lavas1 z 0 po9t$ out s long ago by ,maccullo*1 ! liquefi$ mat]ials may f9d _! way betwe5 ! /rata to enorm\s di/ances f ! volcanic c5tre4 ,su* ext5d$ flat %eets ( igne\s rock reta9 _! p>allelism ) ! /rata among :i* !y are intrud$ ov] l>ge areas1 & did n probably produce any m>k$ ph5om5a at ! surface4 ,b 9 ! case ( less fluid lavas1 su* z ^? ( int]m$iate or acid composition1 = example1 ! effect w\ld be f> o!rwise4 ,su* lavas1 n fl[+ readily f ! c5tre ( eruption1 w\ld t5d to =m great bulky l5ticul> masses betwe5 ! /rata :i* !y =c$ asund]1 &1 9 s do+1 c\ld n fail to upheave & fissure ! great m\nta9-mass above4 ,va/ l5ticul> masses ( tra*ytic rock1 ?us evid5tly =c$ betwe5 /rata1 h be5 describ$ by ,mr4 ,g4 ,k4 ,gilb]t1 z occurr+ 9 ! ,h5ry ,m\nta9s ( ,s\!rn ,utah1 & by him h be5 d5om9at$ 'laccolites1' or /one-ci/]ns4 ,:e!r ! great basaltic %eets1 l ^? describ$ by ,maccullo*1 & ^? m bulky l5ticul> res]voirs ( rock ( :i* ,mr4 ,gilb]t has giv5 u su* an admirable acc\nt1 7 9 all cases connect$ ) ! surface1 may well be a matt] = d\bt4 ,x is q possible t1 9 "s cases1 liquefi$ masses ( rocky mat]ials 9 seek+ to =ce _! way to ! surface only succe$$ 9 ?us f9d+ a way = !mselves betwe5 ! /rata1 & _! en]gy 0 exp5d$ be=e ! surface 0 rea*$ & explosive action took place4 ,b x is an und\bt$ fact t b5ea? _m ( ! old volcanoes1 ( :i* ! int]nal /ructure is n[ reveal$ to u by ! action ( d5ud+ =ces1 great intrusive %eets & laccolites ab\nd2 & we _c d\bt t b5ea? volcanoes n[ 9 a /ate ( eruption1 or 9 ^? :i* h b rec5tly become ext9ct1 simil> /ructures mu/ be 9 c\rse ( =mation4 ,sid5ote3 ,,effects ,,( ,,intrusion ,,b5ea? ,,cones4 ,t great upheav+ =ces h op]at$ on volcanoes1 subsequ5tly to ! accumulation ( _! mat]ials1 we h suffici5t evid5ce 9 ! ,val del ,bove ( ,etna1 ! ,cald]a ( ,palma1 ! ,corral ( ,madeira1 c4 ,9 all ( ^! cases we f9d a radial fissure 7'b>ranco'7 lead+ into a great crat]al holl[2 & ^! radial fissures are ( su* wid? & dep? t _! orig9 c only be ref]r$ to a disruptive =ce l t :i* w\ld be ex]cis$ by ! intrusion ( masses ( m or less imp]fectly fluid mat]ial betwe5 ! subjac5t /rata4 ,^! facts1 ( c\rse1 l5d no c\nt5ance to ! views =m]ly held by _m geologi/s1 bo? 9 ,g]many & ,france1 t ! mat]ials ( :i* volcanoes are built up 7 deposit$ 9 an approximately horizontal position1 & 7 subsequ5tly bl[n up l a gigantic bubble4 ,9 ,etna1 ,palma1 & ,madeira we f9d abundant pro(s t ! mass exi/$ z a great volcanic cone be=e ! production ( ! fissures 7b>rancos71 :i* we h ref]r$ to ! =ce ex]cis$ dur+ ! intrusion ( great igne\s masses b5ea? !m4 ,b besides ! horizontally-dispos$ intrusive %eets & laccolites1 great1 radiat+1 v]tical fissures are produc$ by ! heav+ =ces act+ b5ea? ^? volcanic c5tres :i* h be5 clos$ up & 'cicatris$' by ! exudation f !m ( subt]ranean mat]ials4 ,^! v]tical intrusions1 :i* we call dykes1 l ! horizontal ones1 diff] 9 "*1 accord+ to ! nature ( ! mat]ials ( :i* !y are compos$4 ,dykes ( acid & int]m$iate lava are usually ( consid]able wid?1 & d n ext5d to great di/ances f ! c5tres ( eruption4 ,dykes compos$ ( ! m-liquid1 basic lavas1 on ! o!r h&1 may ext5d to ! di/ance ( hundr$s ( miles f ! c5tral v5t4 ,! way 9 :i* comp>atively n>r[1 basaltic dykes are f\nd runn+ 9 approximately /raight l9es = su* enorm\s di/ances is a v /rik+ fact1 & be>s ! /ronge/ evid5ce to ! heav+ & exp&+ =ces at "w at volcanic c5tres1 dur+ & subsequ5tly to ! extrusion ( ! igne\s products at ! surface4 ,^! basaltic dykes occur 9 su* prodigi\s numb]s ar\nd "s volcanic v5ts1 t ! :ole ( ! /ratifi$ rocks 9 ! imm$iate vic9ity are brok5 up by a complete network ( !m1 cross+ & int]lac+ 9 ! mo/ complicat$ fa%ion4 ,f>!r away f ! v5ts1 simil> dykes are f\nd 9 small] numb]s1 evid5tly radiat+ f ! same c5tre1 & sometimes ext5d+ to a di/ance ( m ?an a hundr$ miles f x4 ,n[h]e c we f9d m beautiful illu/rations ( su* dykes ?an 9 ! ,we/]n ,isles ( ,scotl&4 ,:5 compos$ ( mat]ials :i* d n s easily und]go decomposition z ! surr\nd+ rocks1 !y /& up l va/ walls2 b :51 on ! o!r h&1 !y are m readily act$ on by atmosph]ic moi/ure ?an are ! rocks :i* enclose !m1 !y give rise to deep tr5*es ) v]tical sides1 :i* r5d] ! c\ntry almo/ impassable4 ,sid5ote3 ,,/ructure ,,( ,,intrusive ,,masses4 ,! lava consolidat+ 9 ^! horizontal intrusions 7%eets & laccolites71 & ! v]tical intrusions 7dykes71 is usually m cry/all9e 9 /ructure ?an ! simil> mat]ials p\r$ out at ! surface4 ,9 ! same dyke or %eet1 :5 x is ( great wid?1 we (t5 f9d e v>iation--f a glassy mat]ial =m$ by ! rapid cool+ ( ! mass :]e x is 9 contact ) o!r rocks1 to ! p]fectly cry/all9e or granitic v>ieties :i* =m ! c5tre ( ! intrusion4 ,x is 9 ^! dykes & o!r intrusions t we f9d ! mo/ conv9c+ evid5ce ( ! tru? ( ! conclusions1 :i* we h enunciat$ 9 a =m] *apt]1 conc]n+ ! dep5d5ce ( ! /ructure ( an igne\s rock ^u ! conditions "u :i* x has consolidat$4 ,"o mat]ial is f\nd1 "u v>y+ conditions1 assum+ ! *>act]s ( obsidian1 rhyolite1 qu>tz-felsite1 or granite2 ano!r1 "u ! same set ( conditions1 tak+ ! =m ( ta*ylyte1 basalt1 dol]ite1 & gabbro4 ,t ^! great intrusive masses1 %eets & dykes1 9 _! passage betwe5 ! s$im5t>y rocks sometimes f9d places :]e ! ov]ly+ /rata are ( su* ?9ness or incoh]5ce t ! liquefi$ rocks are able to =ce a way = !mselves to ! surface1 we h ! cle>e/ pro(4 ,9 "s dykes we f9d ! rock 9 _! upp] portions los+ its compact "* & becom+ op5 & scoriace\s1 %[+ t ! pressure _h be5 s f> dim9i%$ z to all[ ( ! imprison$ wat] fla%+ into /eam4 ,all r\nd great volcanoes :i* h become ext9ct we frequ5tly f9d s]ies ( small volcanic cones1 :i* h evid5tly be5 ?r[n up along ! l9es :]e ! great lava-fill$ fissures1 :i* we h be5 describ+1 h rea*$ ! surface & giv5 rise to explosive action !re4 ,! l9e> arrangem5t ( ^! small cones1 :i* are ?r[n up 9 ! pla9s surr\nd+ va/ volcanic m\nta9s t h become ext9ct1 is v /rik+4 ,! num]\s 'puys' ( ! ,auv]gne & adjo9+ volcanic regions ( ,c5tral ,france are = ! mo/ "p small scoria- & lava-cones :i* 7 ?r[n up along great l9es ( fissure radiat+ f ! imm5se1 c5tral1 volcanic m\nta9s ( ! di/rict1 aft] !y _h become ext9ct4 ,^! scoria-cones & ! small lava-/reams :i* fl[ f !m1 z 0 s well %[n by ,mr4 ,scrope1 m>k ! late/ ef=ts ( ! volcanic =ces b5ea? ! di/rict be=e !y f9ally sank into complete ext9ction4 ,9 ! ,we/]n ,isles ( ,scotl&1 z ,i h else:]e %[n1 we c /udy ! =mation ( ^! lat]-=m$ cones 9 ! pla9s ar\nd ext9ct volcanic m\nta9s1 ) ! additional advantage ( hav+ reveal$ to u1 by ! action ( ! d5ud+ =ces1 _! connection ) ! great radiat+ fissures4 ,x has be5 %[n t ! sev]al /ages 9 ! decl9e ( ea* volcanic outbur/ is m>k$ by ! appe>ance at ! v5t ( c]ta9 acid gases4 ,9 ! same way1 aft] ! ejection ( solid mat]ials f a volcanic v5t has come to an end1 c]ta9 gase\s sub/ances cont9ue to be evolv$2 & z ! temp]ature at ! v5ts decl9es1 ! nature ( ! volatile sub/ances emitt$ f !m und]goes a regul> s]ies ( *anges4 ,sid5ote3 ,,ord] ,,( ,,emission ,,( ,,volcanic ,,gases4 ,m4 ,f\qu1 by a c>eful s]ies ( analyses ( ! gases :i* he collect$ at diff]5t gase\s v5ts1 or fum>oles z !y are call$1 9 ! crat] ( ,vulcano1 has be5 able to def9e ! g5]al relations :i* appe> to exi/ betwe5 ! temp]ature at a volcanic orifice & ! volatile sub/ances :i* issue f x4 ,he f\nd t 9 fum>oles1 9 :i* ! temp]ature exce$$ #cfj c5tigrade1 & 9 :i* 9 consequ5ce /rips ( z9c 7 fus$ by ! /ream ( issu+ gas1 ! analysis ( ! products %[$ sulphur\s acid & hydro*loric add to be pres5t 9 l>ge quantities1 & sulphurett$ hydrog5 & c>bonic acid 9 mu* small] proportions4 ,ar\nd ^! excessively heat$ fum>oles1 ! lips ( :i* (t5 appe> at night to be r$-hot1 consid]able deposits ( sulphide ( ars5ic1 *loride ( iron1 *loride ( ammonium1 boracic acid1 & sulphur 7 tak+ place4 ,x 0 f\nd1 h[ev]1 t z ! temp]ature ( ! v5t decl9$1 ! emission ( ! sulphur\s acid & hydro*loric acid dim9i%$1 & ! quantity ( sulphurett$ hydrog5 & c>bonic acid m+l$ ) !m 0 proportionately increas$4 ,9 ! same way x appe>s to be a univ]sal rule t :5 a volcanic v5t s9ks into a condition ( tempor>y quiesc5ce or complete ext9ction ! p[]fully acid gases1 hydro*loric acid & sulphur\s acid1 make _! appe>ance 9 ! fir/ in/ance1 & at a lat] /age ^! are gradually replac$ by sulphurett$ hydrog5 & c>bonic acid4 ,( ^! facts we f9d a v beautiful illu/ration 9 ! ,campi ,phlegri ne> ,naples4 ,) ! exception ( ,monte ,nuovo1 ! volcano :i* has mo/ rec5tly be5 9 a /ate ( activity 9 t di/rict is ! ,solfat>a4 ,f c]ta9 ap]tures 9 ! floor ( ! crat] ( ! ,solfat>a !re issue cont9ually wat]y vap\rs1 sulphur\s acid1 sulphurett$ hydrog51 hydro*loric acid1 & *loride ( ammonium4 ,! action ( ^! sub/ances ^u "o ano!r1 & ^u ! volcanic rocks ?r\gh :i* !y pass1 gives rise to ! =mation ( c]ta9 *emical products :i*1 f a v e>ly p]iod1 h be5 collect$ on acc\nt ( _! comm]cial value4 ,! action ( ^! add gases ^u ! surr\nd+ rocks is v m>k$2 effloresc5t deposits ( v>i\s sulphates & *lorides take place 9 all ! crevices & vesicles ( ! rock2 sulphur & sulphide ( ars5ic are also =m$ 9 consid]able quantities2 & ! tra*ytic tuffs1 depriv$ ( _! iron-oxide1 alkal9e e>?s & alkalies1 :i* are conv]t$ into soluble sulphates & *lorides1 are r$uc$ to a :ite1 p[d]y1 silice\s mass4 ,_m volcanoes1 :i* h sunk into a /ate ( quiesc5ce or ext9ction l ! ,solfat>a ( ,naples1 exhibit ! same t5d5cy to give (f great quantities ( ! p[]fully-acid gases :i* act ^u ! surr\nd+ rocks1 & deprive !m ( _! col\r & consi/5cy4 ,su* volcanoes are said by geologi/s to h sunk into ! 'solfat>a /age4' ,sid5ote3 ,,solfat>a-,,/age ,,( ,,volcanoes4 ,at ! ,lake ( ,agnano & "s o!r po9ts 9 ! ,campi ,phlegri1 h[ev]1 we f9d fissures f :i* ! less-p[]fully acid gases1 sulphurett$ hydrog5 & c>bonic acid1 issue4 ,^! gases z !y1 are p\r$ =? f ! v5ts are f\nd to be little1 if at all1 above ! temp]ature ( ! atmosph]e4 ,sulphurett$ hydrog5 is an inflammable gas1 & 9 ! s-call$ salses & mud-volcanoes1 at :i* x is eject$ 9 consid]able quantities1 x n unfrequ5tly takes fire & bums ) a conspicu\s flame4 ,c>bonic acid on acc\nt ( its great d5sity t5ds to accumulate 9 volcanic fissures & crat]s r ?an to m+le ) ! surr\nd+ atmosph]e4 ,at ! s-call$ ,grotto del ,cane1 beside ! ,lago ,agnano1 x is ! cu/om to %[ ! pres5ce ( ?is heavy & suffocat+ gas by ?ru/+ a dog into x1 ! poor animal be+ reviv$1 be=e life is q ext9ct1 by p\r+ cold wat] ov] x4 ,at ! ,bdos ,hegy or '/9k+ hill' ( ,transylvania1 c>bonic acid & sulphurett$ hydrog5 are emitt$ 9 consid]able quantities1 & x is possible to take a ba? ( ! heavy gas1 ! head be+ kept c>efully above ! con/ant level ( ! exhalations4 ,al?\gh ! /ories ( ! anci5t ,av]nian lake1 across :i* no bird c\ld fly )\t suffocation1 & ( ! ,guevo ,upas1 or ,poison ,valley ( ,java1 :i* x has be5 said no liv+ be+ c cross1 may n improbably be exagg]ations ( ! actual facts1 yet !re is a basis ( tru? 9 !m 9 ! exi/5ce ( old volcanic fissures & crat]s :i* evolve ! poison\s sulphurett$ hydrog5 & c>bonic acid gases4 ,besides ! gases :i* we h already nam$1 & :i* are ! mo/ common at & *>act]i/ic ( volcanic v5ts1 !re are "s o!rs :i* are n unfrequ5tly emitt$4 ,fir/ among ^! we mu/ m5tion boracic acid1 :i*1 ?\gh n a rem>kably volatile sub/ance1 is easily c>ri$ along 9 a f9e /ate ( division 9 a curr5t ( /eam4 ,at ,monte ,c]boli & ,monte ,rotondo 9 ,tuscany1 great quantities ( /eam jets accompani$ by sulphurett$ hydrog5 & boracic acid issue f ! rocks1 & ^! jets be+ direct$ into artificial bas9s ( wat]1 ! boracic acid is cond5s$ & is recov]$ by evaporation4 ,we h already notic$ t boracic add is evolv$ ) ! gases at ,vulcano & o!r crat]s2 & ! "p :i* ?is sub/ance plays 9 volcanic di/ricts is %[n by ! fact t _m ( ! rocks1 fill+ old subt]ranean volcanic res]voirs1 are f\nd to be greatly alt]$ & to h new m9]als develop$ 9 _! mid/ ?r\gh ! action ^u !m ( boracic acid4 ,ammonia & v>i\s comp\nds ( c>bon1 nitrog51 & hydrog5 are among ! gases evolv$ f volcanic v5ts4 ,9 "s cases ^! gases may be produc$ by ! de/ructive di/illation ( organic mat]ials 9 ! s$im5t>y rocks ?r\gh :i* volcanic outbur/s take place4 ,b x is f> f impossible t "u ! conditions ( temp]ature & pressure :i* exi/ at ! volcanic foci1 direct *emical union may take place betwe5 sub/ances1 :i* at ! surface appe> to be p]fectly in]t 9 ea* o!r's pres5ce4 ,:5 ! temp]ature at volcanic fissures is no long] suffici5tly high to cause wat] to issue 9 ! condition ( vap\r or /eam1 z is ! case at ! '/ufas' :i* we h describ$1 x comes =? 9 ! liquid /ate4 ,wat] s issu+ f old volcanic fissures may v>y 9 its temp]ature1 f ! boil+ po9t d[nw>ds4 ,sid5ote3 ,,geys]s ,,& ,,hot-,,spr+s4 ,:5 ! wat] issues at a temp]ature little remov$ f ! boil+ po9t1 x is apt to give rise to int]mitt5t spr+s or geys]s1 ! eruptions ( :i* exhibit a rem>kable analogy ) ^? ( ord9>y volcanoes4 ,geys]s may inde$ be describ$ z volcanoes 9 :i* heat$ wat]1 in/ead ( molt5 rock1 is =c$ out f ! v5t by ! escap+ /eam4 ,!y occur 9 great abundance 9 di/ricts 9 :i* ! subt]ranean action is becom+ dormant or ext9ct1 su* z ,icel&1 ! ,nor? ,isl& ( ,new ,zeal&1 & ! di/rict ( ! ,national ,p>k 9 ! ,rocky ,m\nta9s4 ,_m attempts h be5 made to expla9 ! exact me*anism by :i* ! int]mitt5t action ( geys]s is produc$1 b x is n at all probable t any "o su* explanation w cov] all ! v>i$ ph5om5a exhibit$ by !m4 ,l volcanic outbur/s1 geys] eruptions d\btless orig9ate 9 ! escape ( bubbles ( /eam ?r\gh a liquid mass1 & ?is lib]ation ( /eam foll[s any relief ( pressure4 ,9 di/ricts :]e va/ masses ( lava are sl[ly cool+ d[n f a /ate ( inc&esc5ce1 & surface wat]s are f9d+ _! way d[nw>ds :ile subt]ranean wat]s are f9d+ _! way upw>ds1 !re c be no lack ( ! necess>y conditions = su* outbur/s4 ,sometimes ! eruptions ( geys]s take place at %ort & regul> int]vals1 at o!r times !y occur at wide & irregul> int]vals ( "t4 ,9 "s cases ! outbur/s take place spontane\sly1 & at o!rs ! action c be ha/5$ by *ok+ up ! v5t ) /ones or e>?4 ,o!r hot spr+s1 l ! ,/rudel ( ,c>lsbad1 rise above ! surface 9 a con/ant jet1 :ile mo/ ( !m issue quietly & fl[ l ord9>y spr+s4 ,al?\gh ! viol5t & p>oxysmal outbur/s ( volcanic m\nta9s arre/ ! att5tion1 & p[]fully impress u ) a s5se ( ! volcanic activity go+ on b5ea? ! e>?'s surface1 yet x may well be d\bt$ :e!r ! quantity ( heat1 :i* ! e>? gets rid ( by _! means1 at all approa*es 9 am\nt t :i* is quietly dissipat$ by means ( ! num]\s '/ufas1' gase\s exhalations1 & !rmal spr+s :i* occur 9 su* abundance all ov] its surface4 ,= :ile ! =m] are int]mitt5t 9 _! action1 & p[]ful outbur/s are int]rupt$ by long p]iods ( re/1 ! action ( ! latt]1 ?\gh feeble1 is usually cont9u\s4 ,sid5ote3 ,,effects ,,( ,,hot-,,spr+s4 ,mo/ p may reg>d ! hot spr+ ( ,ba? z a v slight manife/ation ( volcanic activity4 ,?is spr+ issues at a con/ant temp]ature ( #di ,c1 or #abj ,fahr4 ,z1 h[ev]1 no less ?an #ahj1jjj gallons ( wat] issue daily f ?is s\rce1 we may well und]/& h[ great is ! am\nt ( heat ( :i* ! e>?'s cru/ is reliev$ by its ag5cy4 ,x may inde$ be d\bt$ :e!r its action 9 ?is way is n at lea/ equal to t ( a consid]able volcano :i*1 ?\gh s mu* m viol5t1 is int]mitt5t 9 its action4 ,nor are !rmal spr+s by any means ineffective ag5ts 9 br++ mat]ials f ! int]ior ( ! e>?'s cru/ & deposit+ x at ! surface4 ,! ,ba? spr+ conta9s v>i\s sal9e sub/ances1 pr9cipally sulphates & *lorides1 9 solution 9 its wat]s4 ,^! are quietly c>ri$ by riv]s to ! sea1 & are lo/ to our view4 ,! spr+ has c]ta9ly ma9ta9$ its pres5t condition s9ce ! "t ( ! ,romans1 & ,i f9d t if ! solid mat]ials br\ght f ! int]ior ( ! e>? dur+ ! la/ #b1jjj ye>s _h be5 collect$1 !y w\ld =m a solid cone equal 9 height to ,monte ,nuovo4 ,yet we usually reg>d ! ,campi ,phlegri z a p[]fully-active volcanic di/rict1 & ! subt]ranean action 9 our own c\ntry z q unwor?y ( notice4 ,:5 we rememb] ! fact t on ! cont95t ( ,europe ! hot & sal9e spr+s may be numb]$ by ?\s&s1 & t !y especially ab\nd 9 di/ricts l ,hung>y1 ! ,auv]gne1 ! ,rh9e prov9ces1 & ,c5tral ,italy1 :]e volcanic action has rec5tly become ext9ct1 we %all be able to =m "s slight idea ( ! "w p]=m$ by ^! ag5ts1 n only 9 reliev+ ! e>?'s cru/ ( its sup]flu\s heat1 b 9 transport+ mat]ials 9 a /ate ( solution f ! int]ior ( t cru/ & deposit+ !m at ! surface4 ,! va/ deposits ( silice\s s9t] & ( trav]t9e also be> witness to ! effects produc$ by hot & m9]al spr+s4 ,nor is ! "w ( ^! spr+s conf9$ to ! surface4 ,mr4 ,john ,ar?ur ,phillips has %[n t metallic gold & ! sulphide ( quicksilv] 7c9nab>7 h be5 deposit$ ) ! silica & o!r m9]als =m$ on ! sides ( a fissure f :i* hot spr+s issue at ! surface4 ,!re _c be any d\bt t ! metallic ve9s or lodes1 :i* are ! repositories ( mo/ ( ! metals employ$ 9 ! arts1 h be5 =m$ 9 cracks connect$ ) great volcanic foci1 ! transf] ( ! v>i\s sulphides1 oxides1 & salts :i* fill ! ve9 hav+ be5 effect$ ei!r by solution1 sublimation1 or ! action ( p[]ful curr5ts ( /eam4 ,z ! igne\s activity ( ! di/rict decl9es1 ! temp]ature ( ! issu+ gases & wat]s dim9i%es ) x1 until at la/ ! volcanic =ces appe> to :olly ab&on t region & to be transf]r$ to ano!r4 ,yet ev5 aft] all or ne>ly all indications ( ! volcanic ag5cies cease to make !mselves visible at ! surface1 occasional trembl+s ( ! e>?'s cru/ %[ t p]fect equilibrium has n be5 re/or$ bel[1 b t movem5ts are tak+ place :i* result 9 %ocks t are transmitt$ ?r\gh ! ov]ly+ & surr\nd+ rock-masses z e>?quake vibrations4 ,sid5ote3 ,,nature ,,( ,,volcanic ,,cycles4 ,su* is ! cycle ( *anges :i* appe>s to take place at ea* di/rict ( ! e>?'s surface1 z x successively becomes ! sc5e ( volcanic activity4 ,! invasion ( any p>ticul> area ( ! e>?'s surface by ! volcanic =ces appe>s to be h]ald$ by subt]ranean %ocks caus+ e>?quake vibrations4 ,pres5tly ! orig9ation ( fissures is indicat$ by ! rise ( sal9e & !rmal spr+s1 & ! issu+ ( c>bonic acid & o!r gases at ! surface4 ,z ! subt]ranean activity becomes m pron\nc$1 ! temp]ature ( ! spr+s & emitt$ gases is f\nd to increase1 & at la/ a visible r5t is =m$ at ! surface1 expos+ ! inc&esc5t mat]ials bel[4 ,f ?is op5 fissure :i* has ?us be5 =m$1 ! gas & vap\rs imprison$ 9 ! inc&esc5t rock-mat]ials escape ) su* viol5ce z to disp]se ! latt] 9 scori & du/1 or to cause !m to well out 9 great /reams z lava-fl[s4 ,usually ! action becomes conc5trat$ at "o or sev]al po9ts at :i* ! eject$ mat]ials accumulate to =m volcanic cones4 ,sometimes ! volcanic activity dies away entirely aft] ^! cones are ?r[n up along ! l9e ( fissure1 b at o!rs "s su* c5tre becomes = a long] or %ort] "t ! habitual v5t = ! volcanic =ces 9 ! di/rict1 & by repeat$ ejections ( lavas & fragm5t>y mat]ials at long] or %ort] int]vals ! cone increases bo? 9 height & bulk4 ,:5 ! height ( ! cone has gr[n to a c]ta9 ext5t1 x becomes m easy = ! volcanic en]gies bel[ to r5d ! sides ( ! cone ?an to raise ! molt5 mat]ials to its summit4 ,9 ?is way lat]al or p>asitic cones are ?r[n up on ! flanks ( ! volcanic m\nta91 ! mass be+ alt]nately elevat$ & /r5g!n$ by ! ejections f ! summit & sides respectively4 ,:5 ! volcanic en]gies no long] suffice to raise ! fluid mat]ials to ! summit1 nor to r5d ! sides ( ! volcano1 fissures ) small cones may be =m$ 9 ! pla9s ar\nd ! great c5tral volcano4 ,at la/1 h[ev]1 ?is en]gy dim9i%es s f> t rock mat]ials c no long] be =c$ to ! surface1 ! fissures become seal$ up by consolidat+ lava1 & ! volcanic cones fall into a condition ( ext9ction & decay4 ,! exi/5ce ( heat$ mat]ials at no great dep? f ! surface is indicat$ by ! outbur/ ( gases & vap\rs1 ! =mation ( geys]s1 mud-volcanoes1 & ord9>y !rmal spr+s4 ,b z ! und]ly+ rocks cool d[n1 ! issu+ jets ( gas & vap\r lose _! high temp]ature & dim9i% 9 quantity1 ! geys]s & mud-volcanoes become ext9ct1 & ! !rmal spr+s lose _! peculi> "* or disappe>1 & ?us all manife/ations ( ! igne\s en]gies 9 ! di/rict gradually die away4 ,sid5ote3 ,,duration ,,( ,,volcanic ,,cycles4 ,su* a cycle ( *anges probably requires _m hundr$s ( ?\s&s1 or ev5 _m millions1 ( ye>s = its accompli%m5t2 b by ! /udy ( volcanoes 9 e /age ( _! gr[? & decl9e we are able to recon/ruct ev5 ! m9ute/ details ( _! hi/ory4 ,,*apt] ,,viii4 ,,! ,,di/ribution ,,( ,,volcanoes ,,^u ,,! ,,surface ,,( ,,! ,,globe4 ,x is n by any means an easy task to frame an e/imate ( ! numb] ( volcanoes 9 ! _w4 ,volcanoes1 z we h se51 v>y greatly 9 _! dim5sions--f va/ m\nta9 masses1 ris+ to a height ( ne>ly #be1jjj feet above ! sea-level1 to m]e molehills2 ! small] ones be+ 9 _m cases subsidi>y to l>g]1 & con/itut+ ei!r p>asitic cones on _! flanks1 or 'puys' ar\nd _! bases4 ,volcanoes likewise exhibit e possible /age ( developm5t & decay3 :ile "s are 9 a /ate ( *ronic active eruption1 o!rs are r$uc$ to ! condition ( solfat>as1 & o!rs aga9 h fall5 into a m or less complete /ate ( ru9 ?r\gh ! action ( d5ud+ =ces4 ,ev5 if we conf9e our att5tion to ! l>g] volcanoes1 :i* m]it ! "n ( 'm\nta9s1' & su* ( ^! z we h reason to believe to be 9 a /ill active condition1 our difficulties w be dim9i%$1 b n by any means remov$4 ,volcanoes1 z we h se51 may s9k into a dormant condition t may endure = hundr$s or ev5 ?\s&s ( ye>s1 & !n bur/ =? into a /ate ( r5ew$ activity2 & x is q impossible1 9 _m cases1 to di/+ui% betwe5 ! conditions ( dormancy & ext9ction4 ,conc]n+ c]ta9 small areas 9 ,s\!rn ,europe1 ,we/]n ,asia1 & ,nor!rn ,africa1 hi/orical records1 m or less reliable1 ext5d back ov] p]iods ( sev]al ?\s&s ( ye>s2 b ) reg>d to ! great] "p ( ! re/ ( ! _w we h no in=mation beyond a few hundr$ ye>s1 & !re are consid]able areas :i* h be5 kn[n only = f> %ort] p]iods1 :ile "s are z yet q unexplor$4 ,9 di/ricts almo/ :olly un9habit$1 or roam$ ov] by nomadic tribes1 leg5d & tradition con/itute our only guides--& v unsafe ones !y are--9 ! attempt to det]m9e :at volcanoes h rec5tly be5 9 a condition ( activity4 ,sid5ote3 ,,numb] ,,( ,,active ,,volcanoes4 ,we %all1 h[ev]1 probably be )9 ! limits ( tru? 9 /at+ t ! numb] ( great habitual volcanic v5ts ^u ! globe1 :i* we h reason to believe are /ill 9 an active condition1 is some:]e betwe5 #cjj & #cej4 ,mo/ ( ^! active volcanic v5ts are m>k$ by m or less consid]able m\nta9s1 compos$ ( ! mat]ials eject$ f !m4 ,if we include ! m\nta9s :i* exhibit ! ext]nal conical =m1 ! crat]al holl[s1 & o!r features ( volcanoes1 b conc]n+ ! activity ( :i* we h no record or tradition1 ! numb] w fall little1 if any?+1 %ort ( #a1jjj4 ,! m\nta9s compos$ ( volcanic mat]ials1 b :i* h lo/ ?r\gh d5udation ! ext]nal =m ( volcanoes1 are /ill m num]\s4 ,! small] tempor>y op5+s :i* are usually subord9ate to ! habitual v5ts1 t h be5 active dur+ ! p]iods cov]$ by hi/ory & tradition1 mu/ be numb]$ by ?\s&s & t5s ( ?\s&s4 ,! /ill feebl] manife/ations ( ! volcanic =ces--su* z are exhibit$ 9 '/ufas1' or /eam-jets1 geys]s1 or int]mitt5t hot spr+s1 !rmal & m9]al wat]s1 fum>oles1 emitt+ v>i\s gases1 salses or sp\t+ sal9e & muddy spr+s1 & mud volcanoes--may be reckon$ by millions4 ,x is n improbable t ^! less p[]ful manife/ations ( ! volcanic =ces1 to a great ext5t make up 9 numb] :at !y want 9 individual en]gy2 & ! relief :i* !y af=d to ! imprison$ activities )9 ! e>?'s cru/ may be sc>cely less ?an t :i* results f ! occasional outbur/s at ! #cjj or #cej great habitual volcanic v5ts4 ,9 tak+ a g5]al survey ( ! volcanic ph5om5a ( ! globe1 no fact comes out m /rik+ly ?an t ( ! v unequal di/ribution1 9 diff]5t di/ricts1 bo? ( ! great habitual volcanic v5ts1 & ( ! m9or exhibitions ( subt]ranean en]gy4 ,sid5ote3 ,,volcanoes ,,( ,,! ,,cont95ts4 ,?us1 on ! :ole ( ! cont95t ( ,europe1 !re is b "o habitual volcanic v5t--t ( ,vesuvius--& ?is is situat$ ^u ! %ores ( ! ,m$it]ranean4 ,9 ! isl&s ( ! ,m$it]ranean1 h[ev]1 !re are no less ?an six volcanoes2 namely1 ,/romboli & ,vulcano1 9 ! ,lip>i ,isl&s2 ,etna1 9 ,sicily2 ,graham's ,isle1 a subm>9e volcano1 (f ! ,sicilian coa/2 & ,santor9 & ,nisyros1 9 ! gean ,sea4 ,! ,african cont95t is at pres5t kn[n to conta9 ab\t t5 active volcanoes--f\r on ! we/ coa/1 & six on ! ea/ coa/2 ab\t t5 o!r active volcanoes occur on isl&s close to ! ,african coa/s4 ,9 ,asia1 tw5ty-f\r active volcanoes are kn[n1 b no less ?an twelve ( ^! are situat$ 9 ! p59sula ( ,kamts*atka4 ,no volcanoes are kn[n to exi/ 9 ! ,au/ralian cont95t4 ,! ,am]ican cont95t conta9s a great] numb] ( volcanoes ?an ! divisions ( ! ,old ,_w4 ,!re are tw5ty 9 ,nor? ,am]ica1 tw5ty-five 9 ,c5tral ,am]ica1 & ?irty-sev5 9 ,s\? ,am]ica4 ,?us1 tak5 altoge!r1 !re are ab\t "o hundr$ & sev5te5 volcanoes situat$ on ! great cont95tal l&s ( ! globe1 :ile ne>ly twice z _m occur ^u ! isl&s scatt]$ ov] ! v>i\s oceans4 ,^u exam9+ fur!r into ! di/ribution ( ! cont95tal volcanoes1 ano!r v int]e/+ fact pres5ts itself4 ,! volcanoes are 9 almo/ e case situat$ ei!r close to ! coa/s ( ! cont95t1 or at no great di/ance f !m4 ,!re are1 inde$1 only two exceptions to ?is rule4 ,9 ! great & almo/ :olly unexplor$ table-l& ly+ betwe5 ,sib]ia & ,tibet f\r volcanoes are said to exi/1 & 9 ! ,*9ese prov9ce ( ,mant*\ria sev]al o!rs4 ,m reliable in=mation is1 h[ev]1 ne$$ conc]n+ ^! volcanoes1 situat$1 unlike all o!rs1 at a great di/ance f ! sea4 ,x is a rem>kable circum/ance t all ! oceanic isl&s :i* are n coral-reefs are compos$ ( volcanic rocks2 & _m ( ^! oceanic isl&s1 z well z o!rs ly+ ne> ! %ores ( ! cont95ts1 conta9 active volcanoes4 ,?r\gh ! mid/ ( ! ,atlantic ,ocean runs a ridge1 :i*1 by ! s\nd+s ( ! v>i\s explor+ vessels s5t out 9 rec5t ye>s1 has be5 %[n to divide ! ocean longitud9ally into two bas9s4 ,^u ?is great ridge1 & ! spurs proce$+ f x1 rise num]\s m\nta9\s masses1 :i* con/itute ! well-kn[n ,atlantic isl&s & gr\ps ( isl&s4 ,all ( ^! are ( volcanic orig91 & among !m are num]\s active volcanoes4 ,! ,isl& ( ,jan ,may5 conta9s an active volcano1 :ile ,icel& conta9s ?irte51 & n improbably m2 ! ,azores h six active volcanoes1 ! ,can>ies ?ree2 :ile ab\t eight volcanoes lie (f ! we/ coa/ ( ,africa4 ,9 ! ,we/ ,indies !re are six active volcanoes2 & ?ree subm>9e volcanoes h be5 record$ )9 ! limits ( ! ,atlantic ,ocean4 ,altoge!r1 no less ?an =ty active volcanoes are situat$ ^u ! great subm>9e ridges :i* trav]se ! ,atlantic longitud9ally4 ,sid5ote3 ,,volcanoes ,,on ,,! ,,oceanic ,,isl&s4 ,b along ! same l9e ! numb] ( ext9ct volcanoes is f> great]1 & !re are n want+ pro(s t ! volcanoes :i* are /ill active are approa*+ ! condition ( ext9ction4 ,at a some:at e>li] p]iod ( ! e>?'s hi/ory ! :ole l9e ( ! pres5t ,atlantic ,ocean 0 9 all probability trav]s$ by a *a9 ( volcanoes on ! v gr&e/ scale2 b subm]g5ce has tak5 place1 & only a few portions ( ?is great m\nta9 range n[ rise above ! sea-level1 =m+ ! isolat$ isl&s & isl&-gr\ps ( ! ,atlantic4 ,"h & !re among ^! a /ill active volcano exi/s4 ,b if ! great m$ial *a9 ( ! ,atlantic pres5ts u ) an example ( a *a9 ( volcanic m\nta9s v]g+ on ext9ction1 we h 9 ! l9e ( isl&s sep>at+ ! ,pacific & ,indian ,oceans an example ( a simil> range ( volcanic v5ts :i* are 9 a condition ( ! greate/ activity4 ,9 ! p59sula ( ,kamts*atka !re are twelve active volcanoes1 9 ! ,aleutian ,isl&s ?irty-"o1 & 9 ! p59sula ( ,alaska ?ree4 ,! *a9 ( ! ,kuriles conta9s at lea/ t5 active volcanoes2 ! ,japanese ,isl&s & ! isl&s ly+ to ! s\? ( ,japan tw5ty-five4 ,! great gr\p ( isl&s ly+ to ! s\?-ea/ ( ! ,asiatic cont95t is at ! pres5t "t ! gr&e/ focus ( volcanic activity ^u ! globe4 ,no less ?an fifty active volcanoes occur "h4 ,f>!r s\?1 ! same *a9 is probably cont9u$ by ! f\r active volcanoes ( ,new ,gu9ea1 "o or m subm>9e volcanoes1 & sev]al v5ts 9 ,new ,brita91 ! ,solomon ,isles1 & ! ,new ,hebrides1 ! ?ree active volcanoes ( ,new ,zeal&1 & possibly by ,m\nt ,erebus & ,m\nt ,t]ror 9 ! ,ant>ctic region4 ,altoge!r1 no less ?an #aej active volcanoes exi/ 9 ! *a9 ( isl&s :i* /ret* f ,behr+'s ,/raits d[n to ! ,ant>ctic circle2 & if we include ! volcanoes on ,indian & ,pacific isl&s :i* appe> to be situat$ on l9es bran*+ f ?is p>ticul> b&1 we %all n be wrong 9 ! ass]tion t ?is great sy/em ( volcanic m\nta9s includes at lea/ "o half ( ! habitually active v5ts ( ! globe4 ,a ?ird s]ies ( volcanoes />ts f ne> ! la/ 9 ! neighb\rhood ( ,behr+'s ,/raits1 & /ret*es along ! :ole we/]n coa/ ( ! ,am]ican cont95t4 ,9 ?is great range !re are ab\t eighty active volcanoes4 ,sid5ote3 ,,l9e> ,,arrangem5t ,,( ,,volcanoes4 ,9 consid]+ ! facts connect$ ) ! di/ribution ( volcanoes ^u ! globe1 ! "o :i*1 by its /rik+ "*1 seems to dem& our att5tion 9 ! fir/ in/ance is t ( ! rem>kable l9e> arrangem5t ( volcanic v5ts4 ,we h already se5 t small scoria-cones are (t5 ?r[n up on ! flanks1 or at ! base1 ( a great volcanic m\nta91 along l9es :i* are manife/ly l9es ( fissure4 ,9 ! eruption ( ,etna1 9 #ahfe1 & aga9 9 t ( #ahgd1 ,pr(essor ,silve/ri1 ( ,catania1 witness$ ! actual op5+ ( great fissures on ! nor?-ea/ & nor? sides ( ! m\nta93 & along ! bottom ( ^! cracks ! gl[+ lava 0 cle>ly visible 7fig4 #hd1 page #aid74 ,9 ! c\rse ( a few days1 !re 7 ?r[n up a numb] ( small scoria-cones along ^! l9es ( fissure--^? =m$ on ! fissure ( #ahfe be+ sev5 9 numb]1 & ^? on ! fissure ( #ahgd be+ no less ?an ?irty-six 9 numb]4 ,precisely famili> ph5om5a 7 witness$ ^u ! slopes ( ,vesuvius1 9 #agfj1 :5 a fissure op5$ on ! s\? side ( ! m\nta91 & fifte5 scoria-cones1 :i* are /ill visible1 7 ?r[n up along x4 ,we h already consid]$ ! evid5ce po9t+ to ! conclusion t sy/ems ( volcanoes1 l t ( ! ,lip>i ,isl&s1 are simil>ly rang$ along l9es ( fissures1 & !re is equally good gr\nd = believ+ t ! great l9e> b&s ( volcanoes1 :i*1 z we h se51 /ret* = ?\s&s ( miles1 h _h _! positions det]m9$ by great l9es ( fissure 9 ! e>?'s cru/4 ,:ile1 h[ev]1 ! small] fissures1 ^u :i* r[s ( scoria-cones are ?r[n up1 seem to h be5 9 _m cases op5$ by a s+le ef=t ( ! volcanic =ces1 ! enorm\s fissures1 :i* trav]se s l>ge a portion ( ! surface ( ! globe1 are d\btless ! result ( num]\s manife/ations ( en]gy ext5d+ ov] va/ p]iods ( "t4 ,! greate/ ( ^! b&s along :i* ! volcanic =ces are s p[]fully exhibit$ at ! pres5t day1 is ! "o :i* /ret*es f ne> ! ,arctic circle at ,behr+'s ,/raits to ! ,ant>ctic circle at ,s\? ,victoria4 ,! l9e foll[$ by ?is volcanic b&1 :i*1 z we h se51 includes m ?an "o half ( ! active volcanoes ( ! globe1 is a v s9u\s "o1 & x gives (f num]\s (f%oots ^u ei!r side ( x4 ,! great focus ( ?is int5se volcanic action may be reg>d$ z ly+ 9 ! di/rict betwe5 ! isl&s ( ,borneo & ,new ,gu9ea4 ,f ?is c5tre !re radiate a numb] ( great l9es1 along :i* ! volcanic =ces are exhibit$ 9 ! mo/ p[]ful mann]4 ,! fir/ ( ^! ext5ds nor?w>ds ?r\gh ! ,philipp9e ,isles1 ,japan1 ! ,kurile ,isl&s1 & ,kamts*atka1 giv+ (f a bran* to ! ea/1 :i* passes ?r\gh ! ,aleutian ,isl&s & ! p59sula ( ,alaska4 ,?is b&1 along :i* ! volcanic =ces are v p[]fully active1 is cont9u$ t[>ds ! s\?-ea/ 9 ! ,new ,brita91 ! ,solomon ,isl&s1 ,santa ,cruz1 ! ,new ,hebrides1 ,new ,zeal&1 & ,s\? ,victoria4 ,ea/ & we/ f ! great c5tral focus !re proce$ two pr9cipal bran*es4 ,! =m] ( ^! ext5ds ?r\gh ! ,navigator ,isl&s & ,fri5dly ,isl&s z f> z ,elizabe? ,isl&s4 ,! latt] passes ?r\gh ,java1 & !n turns nor?-we/w>d ?r\gh ,sumatra1 ! ,nicob> ,isl&s1 ! ,&aman ,isl&s up to ! coa/ ( ,burmah4 ,! great b& :i* we h be5 describ+ exhibits ! mo/ /rik+ examples ( volcanic activity to be f\nd ^u ! globe4 ,besides ! #aej or m volcanoes :i* are kn[n to h be5 9 a /ate ( activity dur+ ! hi/orical p]iod1 !re are sev]al hundr$ v p]fect volcanic cones1 _m ( :i* appe> to h b rec5tly become ext9ct1 if inde$1 !y are n simply 9 a dormant condition4 ,= long di/ances ^! *a9s ( volcanic cones are almo/ cont9u\s1 & ! only v consid]able breaks 9 ! s]ies are ^? betwe5 ,new ,zeal& & ! ,new ,hebrides on ! "o h&1 & betwe5 ! =m] isl&s & ,s\? ,victoria on ! o!r4 ,sid5ote3 ,,great ,,volcanic ,,b&s ,,( ,,! ,,globe4 ,mu* less cont9u\s1 b nev]!less v important1 is ! great b& ( volcanoes :i* ext5ds along ! we/]n side ( ! great ,am]ican cont95t1 & conta9s1 ) its bran*es1 ne>ly a hundr$ active volcanoes4 ,on ! nor? ?is great b& is almo/ unit$ ) ! "o we h already describ$ by ! *a9 ( ! ,aleutian & ,alaska volcanoes4 ,9 ,briti% ,columbia ab\t ! p>allel ( #fj ,n4 !re exi/ a numb] ( volcanic m\nta9s1 "o ( :i*1 ,m\nt ,/4 ,elias1 is believ$ to be #ah1jjj feet 9 height1 & sev]al ( ^! h c]ta9ly be5 se5 9 a /ate ( eruption4 ,f>!r s\? 9 ! "p ( ! ,unit$ ,/ates1 t]ritories dra9$ by ! ,columbia ,riv]1 a numb] ( gr& volcanic m\nta9s exi/1 "s ( :i* are probably /ill active1 = geys]s & o!r manife/ations ( volcanic activity ab\nd4 ,f ! s\!rn extremity ( ! p59sula ( ,cali=nia an almo/ cont9u\s *a9 ( volcanoes /ret*es ?r\gh ,mexico & ,guatemala1 & f ?is "p ( ! volcanic b& a bran* is giv5 (f :i* passes ?r\gh ! ,we/ ,indies1 & =ms a connection ) ! great volcanic b& ( ! ,atlantic ,ocean4 ,9 ,s\? ,am]ica ! l9e is cont9u$ by ! active volcanoes ( ,ecuador1 ,bolivia & ,*ili1 b at _m int]m$iate po9ts 9 ! *a9 ( ! ,&es ext9ct volcanoes occur1 :i* to a great ext5t fill up ! gaps 9 ! s]ies4 ,a small (f%oot to ! we/w>d passes ?r\gh ! ,galapagos ,isl&s4 ,! great b& ( volcanoes :i* /ret*es ?r\gh ! ,am]ican cont95t is second only 9 importance1 & 9 ! activity ( its v5ts1 to ! b& :i* divides ! ,pacific f ! ,indian ,ocean4 ,! ?ird volcanic b& ( ! globe is t :i* trav]ses ! ,atlantic ,ocean f nor? to s\?4 ,?is s]ies ( volcanic m\nta9s is mu* m brok5 & int]rupt$ ?an ! o!r two1 & a great] proportion ( its v5ts are ext9ct4 ,?is *a91 z we %all %[ 9 a future *apt]1 atta9$ its condition ( maximum activity dur+ ! di/ant p]iod ( ! ,mioc5e1 & n[ appe>s to be pass+ into a /ate ( gradual ext9ction4 ,beg9n+ 9 ! nor? ) ! volcanic rocks ( ,gre5l& & ,be> ,isl&1 we pass s\?w>ds1 by way ( ,jan ,may51 ,icel&1 & ! ,f>oe ,isl&s1 to ! ,hebrides & ! nor? ( ,irel&4 ,!nce by way ( ! ,azores1 ! ,can>ies & ! ,cape de ,v]de ,isl&s1 ) "s active v5ts1 we pass to ! ru9$ volcanoes ( ,/4 ,paul1 ,f]n&o de ,noronha1 ,asc5sion1 ,/4 ,hel5a1 ,tr9idad & ,tri/an d',acunha4 ,f ?is great ,atlantic b& two bran*es proce$ to ! ea/w>d1 "o ?r\gh ,c5tral ,europe1 :]e all ! v5ts are n[ ext9ct1 & ! o!r ?r\gh ! ,m$it]ranean to ,asia ,m9or1 ! great majority ( ! volcanoes along ! latt] l9e be+ n[ ext9ct1 ?\gh a few are /ill active4 ,! vol canoes on ! ea/]n coa/ ( ,africa may be reg>d$ z situat$ on ano!r bran* f ?is ,atlantic volcanic b&4 ,! numb] ( active volcanoes on ?is ,atlantic b& & its bran*es1 exclusive ( ^? 9 ! ,we/ ,indies1 does n exce$ fifty4 ,sid5ote3 ,,l5g? ,,( ,,! ,,volcanic ,,b&s4 ,f :at has be5 said1 x w be se5 t1 n only d ! volcanoes ( ! globe usually assume a l9e> arrangem5t1 b ne>ly ! :ole ( !m c be %[n to be ?r[n up along ?ree well-m>k$ b&s & ! bran*es proce$+ f !m4 ,! fir/ & mo/ important ( ^! b&s is ne>ly #aj1jjj miles 9 l5g?1 & ) its bran*es conta9s m ?an #aej active volcanoes2 ! second is #h1jjj miles 9 l5g?1 & includes ab\t #ajj active volcanoes2 ! ?ird is mu* m brok5 & int]rupt$1 ext5ds to a l5g? ( ne>ly #a1jjj miles1 & conta9s ab\t #ej active v5ts4 ,! volcanoes ( ! ea/]n coa/ ( ,africa1 ) ,mauritius1 ,b\rbon1 ,rodriguez1 & ! v5ts along ! l9e ( ! ,r$ ,sea1 may be reg>d$ z =m+ a f\r? & subord9ate b&4 ,?us we see t ! surface ( ! globe is cov]$ by a network ( volcanic b&s1 all ( :i* trav]se x 9 s9u\s l9es ) a g5]al nor?-&-s\? direction1 giv+ (f bran*es :i* (t5 run = hundr$s ( miles1 & sometimes appe> to =m a connection betwe5 ! great b&s4 ,^! f\r b&s ( volcanic v5ts1 runn+ 9 a g5]al nor?-&-s\? direction1 sep>ate f\r unequal areas )9 :i* ! exhibitions ( volcanic activity are feeble or q unkn[n4 ,! two gr&e/ ( ! b&s ( volcanic activity1 ) _! bran*es1 =m an almo/ complete s]ies encircl+ ! l>ge/ ( ! oceans4 ,to ?is rule ( ! l9e> arrangem5t ( ! volcanic v5ts ( ! globe & _! accumulation along c]ta9 well-m>k$ b&s1 !re are two v /rik+ exceptions1 :i* we mu/ n[ proce$ to notice4 ,9 ! v c5tre ( ! cont95t =m$ by ,europe & ,asia1 ! l>ge/ unbrok5 l&-mass ( ! globe1 !re rises f ! great c5tral plateau ! rem>kable volcanoes ( ! ,?ian ,%an ,range4 ,! exi/5ce ( ^! volcanoes1 ( :i* only obscure traditional acc\nts _h rea*$ ,europe be=e ! ye> #aheh1 appe>s to be completely e/abli%$ by ! rese>*es ( ! ,russian travell] ,sem5(4 ,?ree volcanic v5ts appe> to exi/ 9 ?is region3 ! active volcanoes ( ,bos*an & ,turfan or ,hot-s*51 & ! solfat>a ( ,urumtsi4 ,at a po9t situat$ ab\t half-way betwe5 ^! ?ree volcanoes & ! sea1 ano!r active v5t1 t ( ,ujung-,holdongi1 is said to exi/4 ,o!r volcanic ph5om5a h be5 /at$ to occur 9 ! great plateau ( ,c5tral ,asia1 b ! exi/5ce ( "s at lea/ ( ^! appe>s to re/ on v d\btful evid5ce4 ,! only acc\nts :i* we h ( ! eruptions ( ^! ,?ian ,%an volcanoes are conta9$ 9 ,*9ese hi/ories & treatises on geography2 & a great s]vice w\ld be r5d]$ to sci5ce c\ld !y be visit$ by "s compet5t explor]4 ,sid5ote3 ,,exceptionally-,,situat$ ,,volcanoes4 ,! second exceptionally-situat$ volcanic gr\p is t ( ! ,s&wi* ,isl&s4 ,:ile ! ,?ian ,%an volcanoes rise 9 ! c5tre ( ! l>ge/ unbrok5 l&-mass1 & /& on ! edge ( ! l(tie/ & greate/ plateau 9 ! _w1 ! volcanoes ( ! ,s&wi* ,isl&s rise almo/ 9 ! c5tre ( ! l>ge/ ocean & f almo/ ! greate/ dep?s 9 t ocean4 ,all r\nd ! ,s&wi* ,isl&s ! sea has a dep? ( f #b1jjj to #c1jjj fa?oms1 & ! isl&-gr\p culm9ates 9 sev]al volcanic cones :i* rise to ! height ( ne>ly #ad1jjj feet above ! sea-level4 ,! volcanoes ( ! ,s&wi* ,isl&s are unsurpass$ 9 height & bulk by ^? ( any o!r "p ( ! globe4 ,) ! exception ( ! two isolat$ gr\ps ( ! ,?ian ,%an & ! ,s&wi* ,isl&s1 ne>ly all ! active volcanoes ( ! globe are situat$ ne> ! limits :i* sep>ate ! great l&- & wat]-masses ( ! globe--t is to say1 !y occur ei!r on ! p>ts ( cont95ts n f> remov$ f _! coa/-l9es1 or on isl&s 9 ! ocean n v di/ant f ! %ores4 ,! fact ( ! g5]al proximity ( volcanoes to ! sea1 is "o :i* has frequ5tly be5 po9t$ out by geograph]s1 & may n[ be reg>d$ z be+ ?or\ghly e/abli%$4 ,ev5 ! app>5tly anomal\s case ( ! ,?ian ,%an volcanoes is susceptible ( explanation if we rememb] ! fact1 n[ well asc]ta9$ by geological rese>*es1 t z late c]ta9ly z ,plioc5e times1 a great inl& sea spread ov] ! di/ricts :]e ! ,caspian1 ! ,sea ( ,aral1 & _m o!r isolat$ lakes are n[ f\nd4 ,^u ! s\!rn %ore ( ?is sea rose ! volcanoes ( ! ,?ian ,%an1 "s ( :i* h n yet fall5 into a /ate ( complete ext9ction4 ,b al?\gh ! facts conc]n+ ! g5]al proximity ( volcanoes to ! ocean may be admitt$ to be ?or\ghly e/abli%$1 yet inf]5ces are sometimes ha/ily drawn f ^! facts :i* ! latt]1 if fairly consid]$1 w n be f\nd to w>rant4 ,x is frequ5tly assum$ t we may ref] all ! rem>kable ph5om5a ( volcanic action to ! p5etration ( sea-wat] to a mass ( inc&esc5t lava 9 ! e>?'s cru/1 & to ! *emical or me*anical action :i* w\ld result f ?is meet+ ( sea-wat] & molt5 rock4 ,& ?is conclusion is suppos$ to f9d support 9 ! circum/ance t _m ( ! gases & volatile sub/ances emitt$ f volcanic v5ts are su* z w\ld be produc$ by ! decomposition ( ! v>i\s salts conta9$ 9 sea-wat]4 ,?is argum5t 9 fav\r ( ! production ( volcanic outbur/s by ! irruption ( sea-wat] into subt]ranean res]voirs1 involves1 z ,mr4 ,scrope long ago po9t$ out1 a curi\s example ( reason+ 9 a circle4 ,x is assum$1 on ! "o h&1 t ! heav+ subt]ranean movem5ts1 :i* give rise to ! fissures by :i* /eam & o!r gases escape to ! surface1 are ! result ( ! passage ( wat] to heat$ masses 9 ! e>?'s cru/4 ,b1 on ! o!r h&1 x is suppos$ t x is ! production ( ^! fissures :i* leads to ! influx ( wat] to ! heat$ mat]ials4 ,if x is ! passage ( wat] ?r\gh ^! fissures :i* produces ! eruptions1 x may be fairly ask$1 :at is x t gives rise to ! fissures8 ,& if1 on ! o!r h&1 !re exi/ subt]ranean =ces compet5t to produce ! fissures1 may !y n also give rise to ! eruptions ?r\gh ! op5+s :i* !y h orig9at$8 ,nor does ! *emical argum5t appe> to re/ ^u any sur] gr\nd4 ,x is true t _m ( ! volatile sub/ances emitt$ f volcanic v5ts are su* z might be produc$ by ! decomposition ( sea-wat]1 b1 ^u ! o!r h&1 !re are n a few sub/ances :i* _c possibly be reg>d$ z s produc$1 &1 all ! mat]ials may equally well be suppos$ to h be5 orig9ally imprison$ 9 ! masses ( subt]ranean lava4 ,sid5ote3 ,,cause ,,( ,,proximity ,,( ,,volcanoes ,,to ,,sea4 ,! problem be=e u is ?is4 ,grant+ t x is prov$ t active volcanoes are always 9 close proximity to ! ocean1 are we to expla9 ! fact by suppos+ t ! ag5cy ( sea-wat] is necess>y to volcanic outbur/s1 or by reg>d+ ! position ( ! coa/-l9es z to "s ext5t det]m9$ by ! di/ribution ( volcanic action ^u ! surface ( ! globe8 ,! fir/ supposition is ! "o :i* p]haps mo/ readily sugge/s itself1 b ! latt]1 z we %all h]eaft] %[1 is "o 9 fav\r ( :i* n a few weighty argum5ts may be advanc$4 ,ano!r problem :i* sugge/s itself 9 connection ) ! di/ribution ( volcanoes is ! foll[+4 ,are ! great depress$ tracts :i* =m ! bottom ( ! oceans1 l ! elevat$ tracts :i* con/itute ! cont95ts1 equally free f exhibitions ( volcanic en]gy8 ,:5 we rememb] ! fact t ! area ( ! ocean b$s is two & ?ree-qu>t] times z great z t ( ! cont95ts1 x w be se5 h[ important ?is "q ( ! exi/5ce ( volcanoes at ! bottom ( ! ocean really is4 ,! fact t rec5t deep-sea s\nd+s h %[n ! deepe/ p>ts ( ! ocean to be ev]y:]e cov]$ ) volcanic dbris is by no means conclusive ^u ?is "q2 =1 z we h se51 ! ejections ( sub-a]ial volcanoes are by ! w9d & waves di/ribut$ ov] e "p ( ! e>?'s surface4 ,sid5ote3 ,,subm>9e ,,eruptions4 ,subm>9e volcanic outbur/s h occurr$ 9 _m p>ts ( ! globe1 b x may well be d\bt$ :e!r any su* outbur/ has ev] comm5c$ at ! bottom ( a deep ocean1 & has succe$$ 9 build+ up a volcanic cone rea*+ to ! surface4 ,mo/1 if n all1 ( ! record$ subm>9e outbur/s h occurr$ 9 ! mid/ ( volcanic di/ricts1 & ! volcanic cones h be5 built up 9 wat] ( no great dep?4 ,inde$1 :5 x is rememb]$ t ! pressure ( ea* #a1jjj fa?oms ( wat] is equival5t to a weight ( m ?an "o ton on e squ>e in* ( ! ocean-bottom1 x is difficult to imag9e ! ord9>y explosive action ( volcanic v5ts tak+ place at abysmal dep?s4 ,if1 h[ev]1 fissures 7 op5$ 9 ! b$s ( ! ocean1 quiet outwell+s ( lava might possibly occur4 ,! solution ( ?is problem ( ! probable exi/5ce ( volcanic outbur/s on ! floor ( ! ocean c only be hop$ = f ! rese>*es ( ! geologi/4 ,! small specim5s ( ! ocean-b$s br\ght up by deep-sea s\nd+-l9es1 tak5 at wide di/ances ap>t1 & includ+ b a few in*es f ! surface1 c c]ta9ly af=d b little in=mation ^u ! "q4 ,b ! geologi/ has ! opportunity ( /udy+ ! sea-bottoms ( v>i\s geological p]iods :i* h be5 upheav$ & are n[ expos$ to 8 view4 ,x 0 at "o "t suppos$ by geologi/s t 9 ! s-call$ 'trap-rocks' we h great lava-%eets :i* mu/ h be5 pil$ ^u "o ano!r1 )\t explosive action4 ,b ! m accurate rese>*es ( rec5t ye>s h %[n t betwe5 ! lay]s ( 'trap-rock1' 9 e "p ( ! globe1 traces ( t]re/rial surfaces & fre%wat] deposits are f\nd2 & ! suppos$ pro(s ( ! abs5ce ( explosive action break d[n no less signally ^u re-exam9ation2 = ! loose1 scoriace\s mat]ials w\ld ei!r be remov$ by d5udation1 or conv]t$ into h>d & solid rocks by ! infill+ ( _! vesicles & air-cavities ) cry/all9e m9]als4 ,x is n possible1 among ! repres5tatives ( =m] geological p]iods1 to po9t to any rocks t c be fairly reg>d$ z hav+ issu$ f great subm>9e fissures1 & x is !re=e fair to conclude t no su* great outbur/s ( ! volcanic =ces take plane at ! pres5t day on ! deep ocean-floors4 ,9 connection ) ! "q ( ! relation betwe5 ! position ( ! volcanic b&s ( ! globe & ! areas cov]$ by ! ocean1 we may m5tion a fact :i* deep-sea s\nd+s appe> to indicate1 namely1 t ! deepe/ holes 9 ! ocean-floor are situat$ 9 volcanic areas4 ,ne> ,japan1 ! s\nd+s ( ! ,u4,s4 %ip ',tusc>ora' %[$ t at two po9ts ! dep? exce$$ #d1jjj fa?oms2 & ! deepe/ s\nd+ obta9$ by ,h4,m4,s4 ',*all5g]1' am\nt+ to #d1ege fa?oms1 0 tak5 9 ! voyage f ,new ,gru9ea to ,japan1 9 ! neighb\rhood ( ! ,ladrone ,isl&s4 ,dep?s ne>ly z great 7 f\nd 9 ! s\nd+s c>ri$ on 9 ! neighb\rhood ( ! volcanic gr\p ( ! ,we/ ,indian ,isl&s4 ,x mu/ be rememb]$1 h[ev]1 t at pres5t our k ( ! dep?s ( ! abysmal portions ( ! ocean is v limit$4 ,a few l9es ( s\nd+s1 (t5 tak5 at great di/ances ap>t1 are all we h to guide u to any conclusions conc]n+ ! floors ( ! great oceans1 & betwe5 ^! l9es are enorm\s areas :i* /ill rema9 altoge!r unexplor$4 ,x may be wise1 !re=e1 to susp5d our judgm5t ^u su* que/ions till m num]\s facts h be5 obta9$4 ,sid5ote3 ,,relations ,,to ,,m\nta9-,,*a9s4 ,ano!r fact conc]n+ ! di/ribution ( volcanoes :i* is wor?y ( rem>k is _! relation to ! great m\nta9-ranges ( ! globe4 ,_m ( ! gr&e/ m\nta9-*a9s h b&s ( volcanoes ly+ p>allel to !m4 ,?is is /9k+ly exhibit$ by ! great m\nta9-masses :i* lie on ! we/]n side ( ! ,am]ican cont95t4 ,! ,rocky ,m\nta9s & ! ,&es consi/ ( fold$ & crumpl$ masses ( alt]$ /rata :i*1 by ! action ( d5ud+ =ces1 h be5 c>v$ into s]ies ( ridges & summits4 ,at _m po9ts1 h[ev]1 along ! sides ( ^! great *a9s1 we f9d t fissures h be5 op5$ & l9es ( volcanoes =m$1 f :i* enorm\s quantities ( lava h fl[$ & cov]$ great tracts ( c\ntry4 ,at "s p>ts ( ! *a91 h[ev]1 ! volcanoes are ( su* height & dim5sions z to ov]look & dw>f ! m\nta9-ranges by ! side ( :i* !y lie4 ,"s ( ! volcanoes ly+ p>allel to ! great ,am]ican axis appe> to be q ext9ct1 :ile o!rs are 9 full activity4 ,9 ! ,ea/]n cont95t we f9d /ill m /rik+ examples ( ! p>allelism betwe5 great m\nta9-*a9s & ! l&s along :i* volcanic activity is exhibit$4 ,/ret*+ 9 a m or less cont9u\s *a9 f ea/ to we/1 ?r\gh ,europe & ,asia1 we f9d ! m\nta9-masses kn[n 9 diff]5t p>ts ( _! c\rse z ! ,pyr5ees1 ! ,alps1 ! ,balkan1 ! ,caucasus1 :i* =m ! axis ( ! ,ea/]n cont95t4 ,^! *a9s consi/ ( num]\s p>allel ridges1 & give (f bran*es on ei!r side ( !m4 ,!y are cont9u$ to ! ea/w>d by ! ,h9doo ,koo% & ! ,himalaya1 ) ! f\r p>allel ranges t cross ! great ,c5tral-,asian plateau4 ,n[1 on ei!r side ( ?is gr& axial sy/em ( m\nta9s1 we f9d a great p>allel b& ( volcanoes4 ,! nor!rn volcanic b& is con/itut$ by ! eruptive rocks ( ! ,auv]gne1 ! ,eifel1 ! ,sieb5gebirge1 ,c5tral ,g]many1 ,bohemia1 ,hung>y1 & ,transylvania1 few1 if any1 ( ! v5ts along ?is nor!rn b& be+ /ill active4 ,! rem>kable volcanoes ( ! ,?ian ,%an range & ( ,mant*\ria may n improbably be reg>d$ z a cont9uation ( ! same great s]ies4 ,! s\!rn b& ( volcanoes1 ly+ p>allel to ! great m\nta9 axis ( ! ,old ,_w1 also consi/s = ! mo/ "p ( ext9ct volcanoes1 b includes n a few v5ts :i* are /ill active4 ,9 ?is b& we include ! ext9ct volcanoes ( ,spa9 & ,s>d9ia1 ! num]\s ext9ct & active v5ts ( ! ,italian p59sula & isl&s1 & ^? ( ! gean ,sea & ,asia ,m9or4 ,we may1 p]haps1 consid] ! scatt]$ volcanoes ( ,arabia & ! nor!rn "p ( ! ,indian ,ocean z a cont9uation ( ! same s]ies4 ,bo? ( ^! b&s may be reg>d$ z (f%oots f ! great mid-,atlantic volcanic *a91 & ! condition ( ! v5ts1 bo? 9 ! pr9cipal b& & its (f%oots1 is su* z to indicate t !y =m p>ts ( a sy/em :i* is gradually s9k+ into a /ate ( complete ext9ction4 ,!re are "s o!r volcanic b&s :i* exhibit a simil> p>allelism ) m\nta9 *a9s2 b1 on ! o!r h&1 !re are "s volcanoes betwe5 :i* & ! ne>e/ m\nta9 axes no su* connection c be trac$4 ,sid5ote3 ,,relation ,,to ,,areas ,,( ,,upheaval4 ,!re is yet "o o!r fact conc]n+ ! mode ( di/ribution ( volcanoes ^u ! surface ( ! globe1 to :i* we mu/ allude4 ,x 0 fir/ e/abli%$ by ,mr4 ,d>w9 z "o ( ! conclusions d]iv$ f ! valuable s]ies ( obs]vations made by him dur+ ! voyage ( ,h4,m4,s4 ',beagle1' & relates to ! position ( active volcanoes ) respect to ! portions ( ! e>?'s cru/ :i* are und]go+ upheaval or subsid5ce4 ,f ! relative position ( ! diff]5t k9ds ( coral-reefs1 & ! fact t reef-=m+ corals _c live at a dep? ( m ?an tw5ty fa?oms b5ea? ! sea-level1 or above tide-m>k1 we are l$ to ! conclusion t c]ta9 areas ( ! e>?'s surface are und]go+ sl[ elevation1 :ile o!r p>ts are z gradually subsid+4 ,?is conclusion is confirm$ by ! occurr5ce ( rais$ bea*es1 :i* are sometimes f\nd at heights ( hundr$s1 or ev5 ?\s&s1 ( feet above ! sea-level1 & ( subm]g$ =e/s1 :i* are n unfrequ5tly f\nd b5ea? ! wat]s ( ! ocean4 ,by a /udy ( ! evid5ces pres5t$ by coral-reefs1 rais$ bea*es1 subm]g$ =e/s1 & o!r ph5om5a ( a simil> k9d1 x c be %[n t c]ta9 wide areas ( ! l& & ( ! ocean-floor are at ! pres5t "t 9 a /ate ( subsid5ce1 :ile o!r equally l>ge areas are be+ upheav$4 ,& ! obs]vations ( ! geologi/ prove t simil> upw>d & d[nw>d movem5ts ( portions ( ! e>?'s cru/ h be5 go+ on ?r\gh all geological times4 ,n[1 z ,mr4 ,d>w9 has s well %[n 9 8 "w on ',coral-,reefs1' if we trace ^u a map ! areas ( ! e>?'s surface :i* are und]go+ upheaval & subsid5ce respectively1 we %all f9d t ne>ly all ! active volcanoes ( ! globe are situat$ ^u ris+ areas1 & t volcanic ph5om5a are conspicu\sly abs5t f ^? p>ts ( ! e>?'s cru/ :i* c be prov$ at ! pres5t day to be und]go+ depression4 ,,*apt] ,,ix4 ,,volcanic ,,action ,,at ,,diff]5t ,,p]iods ,,( ,,! ,,e>?',s ,,hi/ory4 ,x is only 9 comp>atively rec5t times t ! important doctr9e ( geological cont9uity has come to be g5]ally accept$1 z furni%+ u ) a complete & satisfactory explanation ( ! mode ( orig9 ( ! features ( our globe4 ,! great =ces1 :i* are ev] at "w produc+ modifications 9 ^? features1 op]ate s sil5tly & sl[ly1 ?\gh )al s surely1 t )\t ! close/ & mo/ att5tive obs]vation _! effects may be easily ov]look$2 :ile1 on ! o!r h&1 !re are s _m ph5om5a ^u our globe :i* seem at fir/ sight to be> te/imony to ! action ( sudd5 & cata/rophic =ces1 v diff]5t to any :i* appe> to be at pres5t at "w1 t ! t5d5cy to acc\nt = all pa/ *anges by ^! viol5t actions is a v /rong "o4 ,9 spite ( ?is t5d5cy1 h[ev]1 ! real pot5cy ( ! =ces n[ at "w ^u ! e>?'s cru/ has gradually made its way to recognition1 & ! capability ( ^! =ces1 :5 _! effects are accumulat$ ?r\gh suffici5tly long p]iods ( "t1 to br+ ab\t ! gr&e/ *anges1 is n[ almo/ univ]sally admitt$4 ,! mod]n sci5ce ( geology is bas$ ^u ! pr9ciple t ! hi/ory ( ! =mation & developm5t ( ! e>?'s surface-features1 & ( ! organisms ^u x1 has be5 cont9u\s dur+ enorm\s p]iods ( "t1 & t 9 ! /udy ( ! op]ations tak+ place ^u ! e>? at ! pres5t day1 we may f9d ! true key to ! *anges :i* h occurr$ dur+ =m] p]iods4 ,9 no bran* ( geological sci5ce has ! doctr9e ( cont9uity _h to enc\nt] s mu* opposition & misconception z 9 t :i* relates to ! volcanic ph5om5a ( ! globe4 ,= a long "t /ud5ts ( rocks utt]ly fail$ to recognise any relation betwe5 ! mat]ials :i* h be5 eject$ f active volcanic v5ts & ^? :i* h be5 =m$ by simil> ag5cies at e>li] p]iods ( ! e>?'s hi/ory4 ,& :at 0 f> worse1 ! subject became remov$ f ! sph]e ( practical sci5tific inquiry to t ( !ological controv]sy1 ^? :o ma9ta9$ ! volcanic orig9 ( "s ( ! old] rocks be+ br&$ z ! wor/ ( h]etics4 ,sid5ote3 ,,controv]sy ,,conc]n+ ,,orig9 ,,( ,,basalt4 ,) ! !ological aspects ( ! great controv]sy conc]n+ ! orig9 ( basalt & simil> rocks--a controv]sy :i* 0 c>ri$ on ) su* viol5ce & acrimony dur+ ! latt] half ( ! eighte5? c5tury--we h "h no?+ to d4 ,b x may n be un9/ructive to notice ! causes ( ! /range misconceptions :i* = s long a p]iod /ood 9 ! way ( ! acceptance ( rational views ^u ! subject4 ,at ?is p]iod b little _h be5 done 9 /udy+ ! *emical *>act]s ( aque\s & igne\s rock-masses respectively2 & :ile1 on ! "o h&1 ! close simil>ity 9 *emical composition betwe5 ! anci5t basalts & _m mod]n lavas 0 n recognis$1 ! m>k$ di/9ction betwe5 ! composition ( su* mat]ials & mo/ aque\s s$im5ts rema9$1 on ! o!r h&1 equally unkn[n4 ,nor _h any?+ be5 yet accompli%$ 9 ! direction ( ! /udy ( rock-masses by ! aid ( ! microscope4 ,h5ce !re c\ld be no appeal to ^? num]\s /ructural peculi>ities t at once enable u to di/+ui% ! mo/ cry/all9e aque\s rocks f ! mat]ials ( igne\s orig94 ,on ! o!r h&1 !re und\bt$ly exi/ rocks ( a black col\r & cry/all9e /ructure1 sometimes pres5t+ a /rik+ simil>ity 9 g5]al appe>ance to ! basalts1 :i* conta9 fossils & are und\bt$ly ( aque\s orig94 ,?us on ! %ore ne> ,portru%1 9 ! ,nor? ( ,irel&1 & 9 ! sk]ries :i* lie (f t coa/1 !re occur great rock-masses1 "s ( :i* und\bt$ly agree ) basalt 9 all _! *>act]s1 :ile o!rs are d>k-col\r$ & cry/all9e1 & are frequ5tly cr[d$ ) ,ammonites & o!r fossils4 ,we n[ "k t ! explanation ( ^! facts is z foll[s4 ,ne> :]e ! t[n ( ,portru% is n[ situat$1 a volcanic v5t 0 op5$ 9 ,mioc5e times ?r\gh rocks ( ,lias %ale4 ,f ?is igne\s c5tre1 %eets & dykes ( basaltic lava 7 giv5 (f1 & 9 consequ5ce ( _! contact ) ^! masses ( lava1 ! ,lias %ales 7 bak$ & alt]$1 & assum$ a cry/all9e "*1 ?\gh ! traces ( ! fossils conta9$ 9 !m 7 n altoge!r oblit]at$4 ,9 ! la/ c5tury ! me?ods :i* _h be5 devis$ = ! discrim9ation ( rocks 7 s imp]fect t no di/9ction 0 recognis$ betwe5 ! true basalt & ! alt]$ %ale1 & specim5s ( ! latt] conta9+ ,ammonites f\nd _! way to almo/ e museum 9 ,europe1 & 7 us$ z illu/rations ( ! 'orig9 ( basalt by aque\s precipitation4' ,ano!r s\rce ( ! widely-spread error :i* prevail$ conc]n+ ! orig9 ( basalt1 0 ! failure to recognise ! nature ( ! alt]ations :i* take place 9 ! "* ( rock-masses 9 consequ5ce ( ! passage ?r\gh !m1 dur+ enorm\s p]iods ( "t1 ( wat] conta9+ c>bonic acid & o!r active *emical ag5ts4 ,! casual obs]v] does n recognise ! resemblance :i* exi/s betwe5 c]ta9 ornam5tal m>bles & ! loose accumulations ( %ells & corals :i* =m _m sea-bea*es2 b close exam9ation %[s t ! =m] consi/ ( ! same mat]ials z ! latt]1 b\nd toge!r by a cry/all9e infill+ ( c>bonate ( lime1 :i* has be5 deposit$ 9 all ! cavities & int]/ices ( ! mass4 ,9 ! same way1 z we h already se51 ! vesicles & int]/ices ( heaps ( scori may1 by ! p]colation ( wat] ?r\gh ! mass1 become s fill$ ) v>i\s cry/all9e sub/ances1 t its orig9al *>act]s are entirely mask$4 ,b ! progress ( *emical & microscopic rese>* has effectually remov$ ^! s\rces ( error4 ,_m rocks ( aque\s orig91 =m]ly conf\nd$ ) ! basalts1 h n[ be5 relegat$ to _! prop] places among ! diff]5t classes ( rocks2 :ile1 on ! o!r h&1 x has be5 %[n t ! *emical & physical diff]5ces betwe5 ! anci5t basalts & ! mod]n basic lavas are slight & accid5tal1 & _! resemblances are ( ! close/ & mo/ fundam5tal "*4 ,sid5ote3 ,,volcanic ,,orig9 ,,( ',,trap ,,rocks4' ,! notion ( ! aque\s orig9 ( basalt1 :i* 0 s long ma9ta9$ by ! s*ool ( ,w]n]1 has n[ be5 entirely ab&on$1 & ! s-call$ 'trap-rocks' are at ! pres5t day recognis$ z be+ z truly volcanic 9 _! orig9 z ! lavas ( ,etna & ,vesuvius4 ,!re is1 h[ev]1 a ve/ige ( ?is doctr9e ( ,w]n]1 :i* /ill ma9ta9s its gr\nd ) ob/9ate p]si/5ce4 ,_m geologi/s 9 ,g]many :o admit t volcanic ph5om5a1 simil> to ^? :i* are go+ on at ! pres5t day1 mu/ h occurr$ dur+ ! ,t]ti>y & ! lat] ,second>y p]iods1 nev]!less insi/ t among ! e>li] records ( ! _w's hi/ory we f9d no evid5ce :atev] ( su* volcanic action hav+ tak5 place4 ,by ! geologi/s :o hold ^! views x is ass]t$ t :ile ! granites & o!r plutonic rocks 7 =m$ dur+ ! e>li] p]iods ( ! _w's hi/ory1 true volcanic products are only kn[n 9 connection ) ! s$im5t ( ! lat] geological p]iods4 ,"s geologi/s h gone f>!r ev5 ?an ?is1 & ass]t$ t ea* ( ! great geological p]iods is *>act]is$ by ! nature ( ! igne\s ejections :i* h tak5 place 9 x4 ,!y decl>e t granite 0 =m$ only dur+ ! e>lie/ geological p]iods1 & t at lat] dates ! gabbros1 diabases1 porphyries1 dol]ites & basalts1 successively made _! appe>ance1 & f9ally t ! mod]n lavas 7 p\r$ out4 ,a little consid]ation w suffice to conv9ce u t ^! conclusions are n bas$ ^u any good evid5ce4 ,! plutonic rocks1 z we h already se51 exhibit suffici5t pro(s 9 _! highly cry/all9e "*1 & 9 _! cavities conta9+ wat]1 liquefi$ c>bonic acid1 & o!r volatile sub/ances1 t !y mu/ h be5 =m$ by ! v sl[ consolidation ( igne\s mat]ials "u enorm\s pressure4 ,su* pressures1 x is evid5t1 c\ld only exi/ at great dep?s b5ea? ! e>?'s surface4 ,mr4 ,sorby & o!rs h endeav\r$ to calculate :at 0 ! actual ?ickness ( rock "u :i* c]ta9 granites mu/ h be5 =m$1 by measur+ ! am\nt ( contraction 9 ! liquids :i* h be5 imprison$ 9 ! cry/als ( ^! rocks4 ,! conclusions arriv$ at are ( a suffici5tly />tl+ "*4 ,x is inf]r$ t ! granites :i* h be5 ?us exam9$ mu/ h consolidat$ at dep?s v>y+ f #cj1jjj to #hj1jjj feet b5ea? ! e>?'s surface4 ,x is true t 9 arriv+ at ^! results c]ta9 assumptions h to be made1 & to ^! exception may be tak51 b ! g5]al conclusion t granitic rocks c\ld only h be5 =m$ "u su* high pressures z exi/ at great dep?s b5ea? ! surface1 appe>s to be "o :i* is n op5 to reasonable d\bt4 ,if1 !n1 granites & simil> rocks 7 =m$ at ! dep? ( "s miles1 x is evid5t t !y c only h made _! appe>ance at ! surface by ! removal ( ! va/ ?ickness ( ov]ly+ rocks2 & ! sole ag5cy :i* we "k ( t is capable ( effect+ ! removal ( su* enorm\s quantities ( rock-mat]ials1 is d5udation4 ,b ! ag5ts ( d5udation--ra9 & fro/1 riv]s & glaci]s1 & sea-waves--?\gh produc+ gr& results1 yet "w exce$+ sl[ly2 & almo/ inconceivably long p]iods ( "t mu/ h elaps$ be=e masses ( rock sev]al miles 9 ?ickness c\ld h be5 remov$1 & ! subjac5t granites & o!r highly cry/all9e rocks h be5 expos$ at ! surface4 ,sid5ote3 ,,anci5t ,,& ,,mod]n ,,volcanic ,,rocks4 ,x is an admitt$ fact t among ! old] geological =mations1 we mu* m frequ5tly f9d intrusions ( granitic rocks ?an 9 ! case ( y\ng] ones4 ,x is equally true t among ! s$im5ts =m$ dur+ ! mo/ rec5t geological p]iods1 no true granitic rocks h be5 detect$4 ,b if1 z we insi/ is ! case1 granitic rocks c only be =m$ at a great dep? f ! surface1 ! acts we h describ$ are only j :at we might expect to pres5t !mselves "u ! circum/ances4 ,! old] a mass ( granitic rock1 ! great] *ance !re is t ! d5ud+ =ces op]at+ ^u ! ov]ly+ masses1 w h _h an opportunity ( s f> remov+ ! latt] z to expose ! und]ly+ cry/all9e rocks at ! surface4 ,&1 on ! o!r h&1 ! y\ng] cry/all9e rocks are /ill1 = ! mo/ "p1 buri$ "u su* enorm\s ?icknesses ( sup]9cumb5t mat]ials t x is hopeless = u to se>* = !m4 ,nev]!less1 x does occasionally happ5 t1 :]e ! "w ( d5udation has be5 exceptionally rapid 9 its action1 su* cry/all9e rocks =m$ dur+ a comp>atively rec5t geological p]iod1 are expos$ at ! surface4 ,?is is ! case 9 ! ,we/]n ,isles ( ,scotl& & 9 ! ,pyr5ees1 :]e masses ( granite & o!r highly cry/all9e rocks are f\nd :i* 7 evid5tly =m$ dur+ ! ,t]ti>y p]iod4 ,! granites :i* 7 =m$ 9 ,t]ti>y times pres5t no ess5tial po9ts ( diff]5ce f ^? :i* _h _! orig9 dur+ ! e>li] p]iods ( ! e>?'s hi/ory4 ,! =m]1 l ! latt]1 consi/ ( a mass ( cry/als ) no imp]fectly cry/all9e base or gr\ndmass betwe5 !m2 & ^! cry/als include num]\s cavities conta9+ liquids4 ,betwe5 ! granites & ! qu>tz-felsites e possible gradation may be f\nd1 s t x is impossible to say :]e ! "o gr\p ends & ! o!r beg9s2 inde$1 _m ( ! rocks call$ 'granite-porphyries' h ab\t equal claims to be plac$ 9 ei!r class4 ,nor is ! di/9ction betwe5 ! qu>tz-felsites & rhyolites any m /rongly m>k$ ?an t betwe5 ! =m] class ( rocks & ! granites2 "s ( ! m cry/all9e rhyolites ( ,hung>y be+ q undi/+ui%able1 9 _! *emical composition1 _! m9]alogical con/itution1 & _! microscopic *>act]s1 f ! qu>tz-felsites4 ,! m cry/all9e rhyolites are 9 turn f\nd pass+ by ins5sible gradations into ! glassy v>ieties & f9ally into obsidian4 ,sid5ote3 ,,relations ,,betwe5 ,,granite ,,& ,,pumice4 ,a piece ( granite & a piece ( pumice may at fir/ sight appe> to pres5t s _m po9ts ( diff]5ce1 t x w\ld seem q futile to attempt to discov] any connection betwe5 !m4 ,yet1 if we analyse ! two sub/ances1 we may f9d t 9 ultimate *emical composition !y are absolutely id5tical4 ,!re is no?+ irrational1 !re=e1 9 ! conclusion t ! same mat]ials "u diff]5t conditions may assume ei!r ! *>act]s ( granite on ! "o h&1 or ( pumice on ! o!r2 ! =m] be+ consolidat$ "u circum/ances 9 :i* ! *emical & cry/all9e =ces h _h ! free/ play & h us$ up ! :ole ( ! mat]ials to =m cry/allis$ m9]als1 :ile ! latt] has cool$ d[n & solidifi$ rapidly at ! surface1 9 su* a way t only incipi5t cry/allisation has occurr$1 & ! glassy mass has be5 r$uc$ to a fro?y condition by ! escape ( /eam-bubbles f its mid/ ,?is conclusion receives ! /ronge/ support f ! fact t examples ( e /age ( ! *ange1 betwe5 ! glassy condition ( pumice & ! cry/all9e condition ( granite1 may be detect$ among ! mat]ials ( :i* ! globe is built up4 ,!re is /ill ano!r class ( facts :i* may be adduc$ 9 support ( ! same conclusion4 ,_m lavas1 z we h se51 conta9 cry/als ( mu* l>g] dim5sions ?an ^? con/itut+ ! mass ( ! rock1 :i* is !n said to be 'porphyritic' 9 /ructure4 ,! porphyritically emb$d$ cry/als1 :5 c>efully exam9$1 are (t5 se5 to be brok5 & injur$1 & to exhibit r\nd$ edges1 ) o!r indications ( hav+ und]gone transport4 ,:5 exam9$ microscopically1 too1 !y (t5 pres5t ! cavities conta9+ liquids :i* di/+ui% ! cry/als ( plutonic rocks4 ,all ! facts connect$ ) ^! porphyritic lavas po9t to ! conclusion t :ile ! cry/als 9 _! gr\ndmass h sep>at$ f ! liquefi$ mat]ials ne> ! surface1 ! l>ge emb$d$ cry/al1 h be5 float$ up f great dep?s )9 ! e>?'s cru/1 :]e !y _h be5 orig9ally =m$4 ,sid5ote3 ,,granitic ,,repres5tatives ,,( ,,o!r ,,lavas4 ,! c>eful consid]ation ( all ! facts ( ! case leads to ! conclusion t :]e pumice1 obsidian1 & rhyolite are n[ be+ eject$ at ! surface1 ! mat]ials :i* =m ^! sub/ances are1 at v>i\s dep?s 9 ! e>?'s int]ior1 sl[ly consolidat+ 9 ! =m ( qu>tz-felsite1 granite-porphyry & granite4 ,x may be t we c n[h]e po9t to ! example ( a mass ( rock :i* c be trac$ f subt]ranean regions to ! surface1 & is1 "u su* conditions1 actually se5 to pass f ! d5se & cry/all9e condition ( granite to ! vesicul> & glassy =m ( pumice2 b great granitic masses (t5 exhibit a m co>sely cry/all9e condition 9 _! int]ior1 & ! (f%oots & dykes :i* !y give (f n infrequ5tly assume ! =m ( qu>tz-felsite2 :ile1 on ! o!r h&1 ! m sl[ly consolidat$ rocks f\nd 9 ! int]ior ( "s rhyolite masses are n di/+ui%able 9 any way f "s ( ! true qu>tz-felsites4 ,t :i* is true ( ! lavas ( acid composition is equally true ( ! lavas ( int]m$iate & basic "*4 ,! &esites1 ! tra*ytes1 ! phonolites1 & ! basalts h all _! exact repres5tatives among ! plutonic rocks1 & ^! h a p]fectly cry/all9e or granitic /ructure4 ,! plutonic & ! volcanic repres5tatives ( ea* ( ^! gr\ps are id5tical 9 _! *emical composition1 & num]\s int]m$iate gradations c be f\nd betwe5 ! mo/ completely granitic & ! mo/ p]fectly vitre\s or glassy types4 ,9 illu/ration ( ?is fact1 we may aga9 ref] to ! s]ies ( microscopic sections ( rocks giv5 9 ! frontispiece4 ,ano!r objection to ! conclusion t ! volcanic products ( e>li] p]iods ( ! e>?'s hi/ory 7 id5tical 9 "* ) ^? :i* are be+ eject$ at ! pres5t day is bas$ on ! fact ( ! suppos$ non-exi/5ce ( ! scoriace\s & glassy mat]ials :i* ab\nd 9 ! neighb\rhood ( ! active volcanic v5ts4 ,:]e1 x is ask$1 d we f9d among ! old] rocks ( ! globe ! heaps ( lapilli1 du/1 & scori1 ) ! glassy & pumice\s rocks t n[ occur s abundantly 9 all volcanic di/ricts8 ,9 reply to ?is objection1 we may po9t out t ^! accumulations ( loose mat]ials are ( su* a nature z to be capable ( easy removal by d5ud+ ag5ts1 & t z !y are =m$ ^u ! l& !y w1 if n already wa%$ away by ! action ( ra91 floods1 riv]s1 c41 run great risk ( hav+ _! mat]ials di/ribut$1 :5 ! l& s9ks b5ea? ! wat]s ( ! ocean & ! surface is cov]$ by new deposits4 ,) respect to ! glassy rocks x mu/ be rememb]$ t ! action ( wat]1 conta9+ c>bonic acid & o!r sub/ances1 9 p]colat+ ?r\gh su* masses has a t5d5cy to set up cry/all9e action1 & ^! glassy rocks easily und]go 'devitrification'2 x w\ld !re=e be illogical = u to expect glassy rock-masses to reta9 _! vitre\s "* ?r\gh long geological p]iods1 dur+ :i* !y h be5 subject$ to ! action ( wat] & acid gases4 ,b c>eful obs]vation has %[n t ! scoriace\s & vitre\s rocks are by no means abs5t among ! igne\s mat]ials eject$ dur+ e>li] p]iods ( ! e>?'s hi/ory4 ,_! comp>ative infrequ5cy is easily acc\nt$ = :5 we rememb]1 9 ! fir/ place1 ! ease ) :i* su* mat]ials w\ld be remov$ by d5ud+ =ces1 & 9 ! second place1 ! t5d5cy ( ! action ( p]colat+ wat] to de/roy _! *>act]i/ic features1 by fill+ up _! vesicles ) cry/all9e products & by effect+ devitrification 9 _! mass4 ,sid5ote3 ,,simil>ity ,,( ,,anci5t ,,& ,,rec5t ,,lavas4 ,if we g back to ! v olde/ kn[n rock-masses ( ! globe1 ^? :i* are f\nd und]ly+ ! fossilif]\s ,cambrian /rata1 we f9d abundant evid5ce t volcanic action took place dur+ ! p]iod 9 :i* ^! mat]ials 7 be+ accumulat$4 ,?us1 9 ! ,wrek91 z ,mr4 ,allport has s well %[n1 we f9d cle> pro(s t be=e ! long-di/ant p]iod ( ! ,cambrian1 !re exi/$ volcanoes :i* eject$ scori1 lapilli1 & volcanic du/1 & also gave rise to /reams ( lava exhibit+ ! *>act]i/ic /ructures f\nd 9 glassy rocks4 ,9 ^! rocks1 :i* h und]gone a curi\s alt]ation or devitrification1 we /ill f9d all ^? peculi> /ructures--! sphrulitic1 ! p]litic1 & ! b&$--s common 9 ! rhyolites ( ,hung>y1 ) :i* rocks ! ,wrek9 lavas1 9 _! *emical composition1 precisely agree4 ,pr(4 ,bonney1 too1 has %[n t ! rocks ( ,*>nwood ,=e/1 :i* are also probably ( pre-,cambrian age1 conta9 great quantities ( alt]$ volcanic agglom]ates1 tuffs1 & a%es4 ,i h f\nd ! sphrulitic1 p]litic1 & b&$ /ructures exhibit$ by ,briti% lavas ( ! ,cambrian1 ,silurian1 ,devonian & ,c>bonif]\s p]iods1 z well z 9 ^? ( ,t]ti>y age2 & 9 connection ) ^! diff]5t lavas we f9d va/ accumulations1 sometimes ?\s&s ( feet 9 ?ickness1 ( volcanic agglom]ates & tuffs :i* h und]gone great alt]ation4 ,all ^! facts po9t to "o conclusion--namely1 t dur+ all pa/ geological p]iods1 mat]ials simil> to ^? :i* are n[ be+ extrud$ f volcanic v5ts 7 p\r$ out on ! e>?'s surface by analog\s ag5cies4 ,if we c\ld trace ! lava-/reams ( ! pres5t day d[n to ! great subt]ranean res]voirs f :i* _! mat]ials h be5 d]iv$1 we %\ld d\btless f9d t at gradually increas+ dep?s1 :]e ! pressure w\ld be great] & ! escape ( heat f ! mass sl[]1 ! rocky mat]ials w\ld by degrees assume m & m cry/all9e *>act]s4 ,we %\ld ?us f9d obsidian or rhyolite ins5sibly pass+ into qu>tz-felsite & f9ally into granite2 tra*yte pass+ into or?oclase-porphyry & sy5ite2 & basalt pass+ into dol]ite1 augite-porphyry1 & gabbro4 ,on ! o!r h&1 if we c\ld replace ! great masses ( /ratifi$ rocks :i* mu/ once h ov]la9 ! granites1 sy5ites1 diorites1 & gabbros1 we %\ld f9d t1 z we approa*$ ! orig9al surface1 ^! igne\s mat]ials w\ld gradually lose _! cry/all9e *>act]s1 & :5 !y 7 p\r$ out at ! surface w\ld take ! =ms ( rhyolite1 tra*yte1 &esite1 & basalt--all ( :i* might occasionally assume ! glassy =ms kn[n z obsidian or ta*ylyte4 ,sid5ote3 ,,alt]$ ,,=ms ,,( ,,anci5t ,,lavas4 ,b :ile we insi/ on ! ess5tial po9ts ( simil>ity betwe5 ! lavas p\r$ out ^u ! surface ( ! e>? dur+ e>li] geological p]iods & ^? :i* are be+ extrud$ at ! pres5t day1 we mu/ n =get t by ! action ( p]colat+ wat] & acid gases1 ! m9]al con/itution1 ! /ructure1 & sometimes ev5 ! *emical composition ( ^! anci5t lavas may und]go a va/ am\nt ( *ange4 ,9 n a few cases ^! *anges 9 ! *>act]s ( a lava may be c>ri$ s f> t ! alt]$ rock be>s b little resemblance to ! lava f :i* x 0 =m$1 & x may be f\nd desirable to give x a new "n4 ,among ! rocks ( aque\s orig9 we f9d simil> diff]5ces 9 ! mat]ials deposit$ at diff]5t geological p]iods4 ,clay1 %ale & clay-slate h ! same composition1 & ! two latt] are evid5tly only alt]$ =ms ( ! fir/ m5tion$1 yet s great is ! diff]5ce 9 _! *>act]s t x is n only all[able1 b desirable1 to give !m di/9ctive names4 ,9 ! same way1 among ! deposits ( ! e>li] geological p]iods we f9d rocks :i* 7 d\btless orig9ally basalts1 b 9 :i* great alt]ations h be5 produc$ by ! p]colation ( wat] ?r\gh ! mass4 ,! orig9al rock has consi/$ ( cry/als ( felsp>1 augite1 oliv9e1 & magnetite di/ribut$ ?r\gh a glassy base4 ,b ! *emical action ( wat] & c>bonic acid may h affect$ all ! +r$i5ts ( ! rock4 ,! outw>d =m ( ! felsp> cry/als may be reta9$ :ile _! sub/ance is *ang$ to kaol9ite1 v>i\s zeolites1 & o!r m9]als2 ! oliv9e maybe alt]$ to s]p5t9e & o!r analog\s m9]als2 ! magnetite *ang$ to hydr\s p]oxide ( iron2 ! augite may be *ang$ to uralite or hornbl5de2 & ! surr\nd+ glassy mass m or less devitrifi$ & decompos$4 ,! h>d1 d5se1 & black rock kn[n z basalt has "u ^! circum/ances become a mu* s(t]1 e>?y-look+ mass ( a r$di%-br[n t9t1 & its diff]5ce f basalt is s m>k$ t geologi/s h agre$ to call x by ano!r "n1 t ( 'melaphyre4' ,ev5 9 _! ultimate *emical compositions ! 'melaphyres' diff] to "s ext5t f ! basalts1 = "s ( ! mat]ials ( ! latt] may h be5 remov$ 9 solution1 & wat]1 oxyg51 & c>bonic acid h be5 introduc$ to comb9e ) ! rema9+ +r$i5ts4 ,b if we c>efully /udy1 by ! aid ( ! microscope1 a l>ge s]ies ( basalts & melaphyres1 we %all f9d t _m rocks ( ! =m] class %[ ! fir/ incipi5t traces ( ^? *anges :i* w\ld r$uce !m to ! latt] class4 ,inde$1 x is q easy to =m a p]fect s]ies f q unalt]$ basalts to ! mo/ completely *ang$ melaphyres4 ,h5ce we are ju/ifi$ 9 conclud+ t all ! melaphyres 7 orig9ally basalts1 j z we inf] t all oaks 7 once acorns4 ,n[ *anges1 simil> to ^? :i* we h se5 to take place 9 ! case ( basaltic lavas1 are exhibit$ by ! lavas ( e o!r class1 :i* h be5 expos$ to ! influ5ce ( ! same ag5cies1--namely1 ! passage ( wat] & acid gases4 ,b inasmu* z ! m9]als compos+ ! basic lavas are = ! mo/ "p mu* m easily affect$ by su* ag5cies ?an are ! m9]als ( acid lavas1 ! anci5t basic rocks are usually f\nd 9 a mu* m highly alt]$ condition ?an are ! acid rocks ( equival5t age4 ,sid5ote3 ,,names ,,giv5 ,,to ,,alt]$ ,,lavas4 ,we ?us see t ea* ( ! classes ( mod]n lavas has its repres5tative 9 e>li] geological p]iods1 9 ! =m ( rocks :i* h evid5tly be5 d]iv$ f ^! lavas1 ?r\gh alt]ations effect$ by ! ag5cy ( wat] & acid-gases t h p]meat$ _! mass4 ,?us1 :ile ! basalts are repres5t$ among ! anci5t geological =mation by ! melaphyres1 ! &esites are repres5t$ by ! porphyrites1 & ! tra*ytes & rhyolites by diff]5t v>ieties ( fel/ones4 ,&1 z we c =m p]fect s]ies illu/rat+ ! gradual *ange f basalt to melaphyre1 s we c arrange o!r s]ies demon/rat+ ! passage ( &esites into porphyrites1 & ( tra*ytes & rhyolites into felsites4 ,x mu/ be rememb]$1 h[ev]1 t ^! *anges d n take place 9 any?+ l det]m9ate p]iods ( "t4 ,occasionally we may f9d lavas ( anci5t date :i* h und]gone surpris+ly little alt]ation1 & 9 o!r cases !re occur lavas belong+ to a comp>atively rec5t p]iod :i* exhibit v m>k$ signs ( *ange4 ,! alt]ation ( ! lavas & o!r igne\s rocks does n1 h[ev]1 /op ) ! production ( ! melaphyres1 porphyrites1 & fel/ones4 ,by ! fur!r action ( ! wat] & c>bonic acid ( ! atmosph]e1 ! basic lavas are r$uc$ to ! s(t e>?y mass kn[n z 'wacke1' & ! int]m$iate & acid lavas to ! simil> mat]ial kn[n z 'clay/one4' ,z ! passage ( wat] & c>bonic acid gas ?r\gh ^! rock-masses goes on1 !y are ev5tually resolv$ into two portions1 "o ( :i* is insoluble 9 wat] & ! o!r is soluble4 ,! insoluble portion consi/s pr9cipally ( qu>tz1 ! cry/als ( :i* are almo/ unattack$ by wat] & c>bonic acid1 & ! hydrat$ silicate ( alum9a4 ,all ! s&s & clays1 :i* toge!r make up m ?an n9e-t5?s ( ! /ratifi$ rocks ( ! globe1 are d\btless d]iv$1 ei!r directly or indirectly1 f ^! insoluble mat]ials sep>at$ dur+ ! decomposition ( volcanic & plutonic rocks4 ,! soluble mat]ials1 :i* consi/ ( ! c>bonates1 sulphates & *lorides ( lime1 magnesia1 soda1 pota%1 & iron1 give rise to ! =mation ( ! lime/ones1 gypsum1 rock-salt1 iron/ones1 & o!r /ratifi$ masses ( ! e>?'s cru/4 ,we ?us see h[ ! igne\s mat]ials ( ! globe1 by _! decomposition1 fami% ! mat]ials = ! /ratifi$ rock-masses4 ,! relations ( ! diff]5t plutonic & volcanic rocks to "o ano!r & to ! mat]ials :i* are d]iv$ f !m are illu/rat$ 9 ! foll[+ table4 ,sid5ote3 ,,relations ,,( ,,alt]$ ,,to ,,unalt]$ ,,lavas4 ,unalt]$ ,alt]$ ,decompos$ ,plutonic ,rocks lavas lavas ,rocks ,granite ,qu>tz-felsite ,rhyolite & 7'qu>tz-porphyry'7 ,obsidian ,fel/one ,sy5ite ,or?oclase-porphyry ,tra*yte ,clay/ones ,diorite ,hornbl5de-porphyry ,&esite ,porphyrite ,miascite ,liebn]ite porphyry ,phonolite 8 -- ,gabbro ,augite-porphyry & ,basalt ,melaphyre ,wacke ,dol]ite ,"s petrograph]s1 inde$1 h ma9ta9$ ! pr9ciple t rocks belong+ to widely sep>at$ geological p]iods1 ev5 :5 !y exhibit no ess5tial po9ts ( diff]5ce1 %\ld nev]!less be call$ by di/9ct names4 ,b su* a sy/em ( classification is calculat$ r to h9d] ?an to advance ! cause ( sci5ce4 ,if ! palontologi/ 7 to adopt ! same pr9ciple & give di/9ct names to ! same fossil1 :5 x 0 f\nd to occur 9 two diff]5t geological =mations1 we c easily und]/& :at confusion w\ld be occasion$1 & h[ ! comp>ison ( ! fauna & flora ( ! diff]5t =mations w\ld be !reby r5d]$ impossible4 ,b ! naturali/1 9 8 diagnosis ( a species1 wisely conf9es himself to ! /ructure & aff9ities ( ! organism be=e him2 & 9 ! same way ! petrograph]1 9 giv+ a "n to a rock1 ought to be guid$ only by 8 /udies ( its *emical composition1 its m9]alogical con/itution1 & its /ructure1 putt+ altoge!r out ( view its geographical di/ribution & geological age4 ,only by /rict att5tion to ?is pr9ciple c we hope to arrive at su* comp>isons ( ! rocks ( diff]5t areas & diff]5t p]iods1 z may s]ve z ! basis = safe inductions4 ,be=e leav+ ?is "q ( ! relation :i* exi/s betwe5 ! igne\s rocks ( diff]5t ages1 x may be well to notice sev]al facts t h be5 reli$ ^u1 z prov+ t ! sev]al geological p]iods are di/+ui%$ by *>act]i/ic igne\s products4 ,x has frequ5tly be5 ass]t$ t ! acid igne\s rocks are pres5t 9 mu* great] quantities 9 connection ) ! old] geological =mations ?an axe ! basic2 :ile1 on ! o!r h&1 ! basic igne\s rocks are said to h be5 extrud$ 9 great] abundance 9 ! m rec5t geological p]iods4 ,b 9 consid]+ ?is "q x mu/ n be =gott5 t1 z a g5]al rule1 ! basic rocks und]go decomposition & dis9tegration f> m rapidly ?an d ! acid rocks4 ,9 consequ5ce ( ?is circum/ance ! *ance ( our f9d+ _! recognisable repres5tatives among ! old] =mations1 is mu* less 9 ! case ( ! =m] class ( rocks ?an 9 ! latt]4 ,z a matt] ( fact1 h[ev]1 we d f9d great masses ( gabbro1 diabase1 & melaphyre associat$ ev5 ) ! olde/ geological =mations1 :ile tra*ytes & rhyolites ab\nd 9 _m volcanic di/ricts :]e active v5ts exi/ at ! pres5t day4 ,^u a g5]al review ( ! subject1 x may well be d\bt$ :e!r ! suppos$ prepond]ance ( acid igne\s mat]ials 9 ! e>li] p]iods ( ! e>?'s hi/ory1 & ( basic igne\s mat]ials dur+ ! lat] p]iods1 re/s on any sub/antial basis ( obs]vation4 ,sid5ote3 ,,augitic ,,& ,,hornbl5dic ,,rocks4 ,ano!r diff]5ce :i* has frequ5tly be5 reli$ ^u1 z di/+ui%+ ! old] igne\s rocks f ^? ( m rec5t date1 is ! suppos$ fact t ! =m] are *>act]is$ by ! pres5ce ( hornbl5de1 ! latt] by ! pres5ce ( augite4 ,x may be admitt$ t ?is di/9ction is a real "o1 b its significance & value are greatly dim9i%$ :5 we rememb] ! relations :i* exi/ betwe5 ! two m9]als 9 "q4 ,hornbl5de & augite are int]e/+ examples ( a dimorph\s sub/ance2 9 *emical composition !y are id5tical1 or r !y are liable to v>iation betwe5 ! same limits1 b 9 _! cry/all9e =ms & optical *>act]s !y diff] f "o ano!r4 ,x has be5 prov$ t hornbl5de is ! /able1 & augite ! un/able condition ( ! sub/ance 9 "q4 ,if hornbl5de be fus$ & all[$ to cool1 x cry/allises 9 ! =m ( augite4 ,on ! o!r h&1 augite-cry/als 9 rocks ( anci5t date are f\nd und]go+ gradual *ange & pass+ into hornbl5de4 ,! m9]al uralite has ! outw>d =m ( augite1 b ! cleavage & optical prop]ties ( hornbl5de2 & !re are n want+ _m facts po9t+ to ! conclusion t rocks :i* n[ conta9 hornbl5de 7 orig9ally augitic masses1 9 :i* ! un/able m9]al 9 _! mid/ has be5 gradually conv]t$ into ! /able "o4 ,!re are1 h[ev]1 two m9]als :i* up to ! pres5t "t h be5 f\nd 9 association only ) ! old] & new] rock-masses respectively4 ,^! are muscovite1 or ! :ite =m ( mica1 :i* occurs 9 s _m granites1 b has n yet be5 discov]$ 9 any mod]n repres5tative ( t rock2 & leucite1 :i* is n yet kn[n 9 rocks ( old] date ?an ! ,t]ti>y4 ,:5 we rememb] t muscovite w\ld appe> to be a product ( deep-seat$ igne\s action1 & is only f\nd 9 rock-masses t h be5 =m$ "u su* conditions1 we %all be ! less surpris$ at its non-occurr5ce 9 rocks ( rec5t date1 especially if we be> 9 m9d ! fact t v few ( ! y\ng] granitic rocks h z yet be5 expos$ at ! surface by d5udation4 ,) respect to leucite1 on ! o!r h&1 x mu/ be rememb]$ t x is a v un/able m9]al :i* appe>s to be easily *ang$ into felsp>4 ,x is by no means improbable1 !re=e1 t "s anci5t igne\s rocks :i* n[ conta9 felsp> 7 orig9ally leucitic rocks4 ,to ! view t ! action ( volcanic =ces ^u ! globe dur+ pa/ geological times 0 simil> 9 k9d to t :i* we n[ obs]ve go+ on ar\nd u1 /ill ano!r objection has be5 rais$4 ,x has be5 ass]t$ t "s ( ! deposits ( igne\s rock associat$ ) ! old] geological =mations are ( su* a nature t !y c\ld n possibly h be5 accumulat$ ar\nd volcanic v5ts ( ! k9d :i* we see 9 op]ation ar\nd u4 ,sid5ote3 ,,volcanic ,,orig9 ,,( ,,anci5t ,,igne\s ,,rocks4 ,mr4 ,mallet has decl>$ t ! igne\s products ( ! ,palozoic p]iod diff] fundam5tally 9 "* f ^? mat]ials =m$ by volcanic action dur+ ! lat] ,second>y & ! ,t]ti>y p]iods4 ,^u :at obs]vations ^! g5]alisations are bas$ he has giv5 u no in=mation1 & ! enorm\s mass ( facts :i* h be5 collect$ 9 rec5t ye>s conc]n+ ! /ructure ( ! lavas & fragm5tal volcanic deposits ( ! pre-,cambrian1 ,cambrian1 ,silurian1 ,devonian & ,c>bonif]\s p]iods1 all po9t to a directly opposite conclusion4 ,! m c>efully we c>ry on our inve/igations conc]n+ ^! anci5t lavas1 by ! aid ( *emical analysis & microscopic /udy1 ! m are we conv9c$ ( ! ess5tial id5tity ( ! anci5t & mod]n volcanic rocks1 bo? 9 _! composition & _! m9ute /ructure4 ,( great masses ( du/ produc$ by cru%+1 su* z ,mr4 ,mallet has suppos$ to h be5 =m$ dur+ ! e>li] geological p]iods1 !re is n ! smalle/ evid5ce2 b we ev]y:]e f9d pro(s1 :5 ! rocks are m9utely exam9$1 ( ! vesicul> /ructure s *>act]i/ic ( mat]ials produc$ by explosive volcanic action4 ,x has frequ5tly be5 ass]t$ t 9 ! great di/ricts cov]$ by basaltic lavas :i* we f9d 9 ! ,rocky ,m\nta9s ( ,nor? ,am]ica1 9 ! ,deccan ( ,india1 9 ,abyss9ia1 & ev5 9 ! ,we/]n ,isles ( ,scotl&1 we h pro(s ( ! occurr5ce1 dur+ e>li] geological p]iods1 ( volcanic action v diff]5t 9 "* f t :i* at pres5t takes place on our globe4 ,x has be5 ass]t$ t ! ph5om5a obs]v$ 9 ^! di/ricts c only be acc\nt$ = by suppos+ t great fissures h op5$ 9 _! mid/1 f :i* lavas h issu$ 9 enorm\s floods unaccompani$ by ! ord9>y explosive ph5om5a ( volcanoes4 ,x mu/ be rememb]$1 h[ev]1 t none ( ! di/ricts 9 "q h be5 subject$ to c>eful & sy/ematic exam9ation ) a view to ! discov]y ( ! v5ts f :i* ^! masses ( lava h issu$1 ) ! exception ( t :i* occurs 9 our own isl&s4 ,9 ?is case1 9 :i* sup]ficial obs]v]s h spok5 ( ! di/rict z be+ cov]$ ) horizontal lava-%eets pil$ ^u "o ano!r to ! dep? ( #c1jjj feet1 c>eful /udy ( ! rock-masses has %[n t ! accumulations ( basalt really consi/ ( a great numb] ( lava-curr5ts :i* h issu$ at successive epo*s cov]+ enorm\s p]iods ( "t4 ,dur+ ! int]vals betwe5 ! emission ( ^! successive lava-curr5ts ! surfaces ( ! old] ones h be5 decompos$1 & =m$ soils ^u :i* =e/s h gr[n up2 !y h be5 erod$ by /reams1 ! valleys s =m$ be+ fill$ ) gravels2 & lakes h be5 orig9at$ on _! surfaces 9 :i* v>i\s accumulations h tak5 place4 ,sid5ote3 ,,truly-,,volcanic ,,orig9 ,,( ,,lava ,,plateaux4 ,x has be5 demon/rat$1 moreov]1 t ! basal-wrecks ( no less ?an five volcanic m\nta9s1 ea* ( :i* mu/ h rivall$ ,etna 9 its proportions1 exi/$ )9 ?is area1 & ! connection ( ! lava-curr5ts1 :i* h delug$ ! surr\nd+ tracts1 ) ^! great volcanoes has be5 cle>ly prov$4 ,x is probable t :5 m c>eful & sy/ematic rese>*es are c>ri$ on 9 ! o!r di/ricts1 9 :i* widely-spread %eets ( basaltic rocks exi/1 simil> volcanic v5ts w be discov]$4 ,x mu/ also be rememb]$ t if su* a c\ntry z ,icel& 7 subject$ to long-cont9u$ d5udation1 ! m\nta9 peaks & cones ( loose mat]ials w\ld be worn away1 ! :ole isl& be+ ?us r$uc$ to a s]ies ( plateaux compos$ ( lava-%eets1 ! connection ( :i* ) ! cry/all9e mat]ials fill+ ! great volcanic v5ts1 a sup]ficial obs]v] might altoge!r fail to recognise4 ,b ev5 :]e we _c trace ! =m] exi/5ce ( great volcanic m\nta9s1 l ^? :i* once rose 9 ! ,hebrides1 x w\ld nev]!less be v ra% to conclude t ! va/ plateaux ( lava-rock mu/ h be5 =m$ z gigantic floods unaccompani$ by ord9>y volcanic action4 ,mr4 ,d>w9 has po9t$ out t 9 cross+ di/ricts cov]$ by lava1 he 0 frequ5tly only able to det]m9e ! limits ( ! diff]5t curr5ts ( :i* x 0 made up1 by an exam9ation ( ! age ( ! trees & ! nature ( ! vegetation :i* _h sprung up on !m4 ,& ev]yone :o has travell$ mu* 9 volcanic di/ricts c confirm ?is obs]vation2 :at appe>s at fir/ sight to be a great cont9u\s %eet ( lava proves ^u m c>eful obs]vation to be compos$ ( a great numb] ( di/9ctly diff]5t lava-curr5ts1 :i* h succe$$ "o ano!r at long] or %ort] int]vals4 ,we mu/ rememb]1 too1 h[ v>i\s 9 k9d are ! volcanic manife/ations :i* pres5t !mselves "u diff]5t circum/ances4 ,sometimes ! am\nt ( explosive action at a volcanic v5t is v great1 & only fragm5tal ejections take place1 compos$ ( ! fro?y scum ( ! lava produc$ by ! escape ( gases & vap\rs f its mid/4 ,b 9 o!r cases ! am\nt ( explosive action may be small1 & great volumes ( igne\s mat]ials may issue z lava-/reams4 ,9 su* cases1 only small scori-cones w\ld be =m$ ar\nd ! v5ts1 & "o half ( su* cones is commonly swept away by ! efflux ( ! lava-curr5ts1 :ile ! rema9d] may be easily remov$ by d5ud+ action or be buri$ "u ! lava-curr5ts issu+ f o!r v5ts 9 ! neighb\rhood4 ,?us x may easily come to pass t :at a sup]ficial obs]v] takes = an enorm\s mass ( basaltic lava p\r$ out f a great fissure at a s+le ef=t1 may prove ^u c>eful obs]vation to be made up ( innum]able lava-curr5ts1 ea* ( :i* is ( mod]ate dim5sions2 & x may fur!r be f\nd t ^! lava-curr5ts1 in/ead ( be+ ! product ( a s+le p>oxysmal ef=t f "o great fissure1 h be5 accumulat$ by num]\s small outbur/s tak+ place at wide int]vals1 f a great numb] ( m9or orifices4 ,sid5ote3 ,,%ift+ ,,( ,,volcanic ,,action ,,9 ,,diff]5t ,,areas4 ,hav+ !n consid]$ ! argum5ts :i* h be5 adduc$ 9 support ( ! view t ! volcanic ph5om5a ( =m] geological p]iods diff] f ^? :i* are /ill occurr+ ^u ! globe1 we may proce$ to /ate ! g5]al conclusions :i* h be5 drawn f ! /udy ( ! volcanic rocks ( ! diff]5t geological p]iods4 ,f a survey ( ! volcanic rocks ( diff]5t ages1 we are l$ to ! int]e/+ & important conclusion t ! sc5e ( volcanic action has be5 cont9ually %ift+ to fre% areas at diff]5t p]iods ( ! e>?'s hi/ory4 ,we f9d repeat$ pro(s t ! volcanic en]gy has made its appe>ance at a c]ta9 "p ( ! e>?'s cru/1 has gradually increas$ 9 int5sity to a maximum1 & !n z sl[ly decl9$4 ,b z ^! manife/ations h di$ away at "o "p ( ! e>?'s surface1 !y h gradually made _! appe>ance at ano!r4 ,9 e di/rict :i* has be5 exam9$1 we f9d abundant pro(s t volcanic en]gy has be5 develop$ at c]ta9 p]iods1 has disappe>$ dur+ long] or %ort] p]iods1 & !n reappe>$ 9 ! same area4 ,& on ! o!r h&1 we f9d t !re is no pa/ geological p]iod 9 :i* we h n abundant evid5ce t volcanic outbur/s took place at "s portion ( ! e>?'s surface4 ,to take ! case ( our own isl&s = example4 ,we "k t dur+ ! pre-,cambrian p]iods volcanic outbur/s occurr$1 traces ( :i* are f\nd bo? 9 ,nor? & ,s\? ,wales1 9 ! ,wrek9 ,*a9 9 ,%rop%ire1 9 ,*>nwood ,=e/1 & 9 p>ts ( ,scotl& & ,irel&4 ,9 ,cambro-,silurian times we h abundant pro(s1 bo? 9 ,nor? ,wales & ! ,lake di/rict1 t volcanic action on ! v gr&e/ scale 0 tak+ place dur+ ! ,ar5ig & ! old] portion ( ! ,ll&eilo p]iods1 & aga9 dur+ ! deposition ( ! ,bala or ,c>adoc b$s4 ,! lavas1 tuffs1 & volcanic agglom]ates eject$ dur+ ^! two p]iods h built up masses ( rock _m ?\s&s ( feet 9 ?ickness4 ,sn[don & ,cad] ,idris among ! ,wel% m\nta9s1 & "s ( ! high] summits ( ! ,lake di/rict1 h be5 c>v$ by d5udation f ! va/ piles ( volcanic mat]ials eject$ dur+ ^! p]iods4 ,9 ,devonian or ,old-,r$-,s&/one times1 volcanic activity 0 r5ew$ ) fre% viol5ce ^u t "p ( ! e>?'s surface n[ occupi$ by ! ,briti% ,isl&s4 ,along ! l9e :i* n[ =ms ! ,grampians !re rose a s]ies ( volcanoes ( ! v gr&e/ dim5sions4 ,b5 ,nevis1 & _m o!rs among ! high] ,scot* m\nta9s1 h be5 c>v$ by d5udation f ! h>d masses ( granite1 qu>tz-felsite1 & o!r plutonic rocks :i* =m$ ! c5tral cores ( ^! anci5t volcanic piles4 ,! rema9s ( ! great lava-%eets1 & ( ! masses ( volcanic agglom]ate eject$ f ^! gr& ,devonian volcanoes1 make up hill-ranges ( no mean altitude1 l ! ,sidlaws1 ! ,o*ils1 & ! ,p5tl&s4 ,sid5ote3 ,,anci5t ,,briti% ,,volcanoes4 ,! volcanic action ( ! ,devonian p]iod 0 prolong$ into ,c>bonif]\s times1 b 0 !n evid5tly dim9i%+ gradually 9 viol5ce4 ,in/ead ( great c5tral volcanoes1 su* z exi/$ 9 ! e>li] p]iod1 we f9d innum]able small v5ts :i* ?rew out tuffs1 agglom]ates & lavas1 & 7 scatt]$ ov] ! di/ricts ly+ ar\nd ! bases ( ! n[ ext9ct ,devonian volcanoes4 ,9 ! c5tral valley ( ,scotl& & 9 _m p>ts ( ,engl&1 we f9d abundant pro(s ( ! exi/5ce ( ^! small & scatt]$ volcanic v5ts dur+ ,c>bonif]\s times4 ,! well-kn[n hill ( ,ar?ur's ,seat1 :i* ov]looks ! city ( ,ed9burgh1 & _m ca/le-cr[n$ crags ( ! ,=? & ,clyde valleys1 are ! worn & d5ud$ relics ( ^! small volcanoes4 ,!re are "s indications :i* po9t to ! conclusion t ! volcanic action ( ! ,new] ,palozoic epo* _h n entirely di$ out 9 ,p]mian times1 b ! evid5ce ^u ?is po9t is n altoge!r cle> & satisfactory4 ,dur+ ne>ly ! :ole ( ! ,second>y or ,mesozoic p]iods ! volcanic =ces rema9$ dormant 9 ! area ( ! ,briti% ,isles4 ,"s small volcanic outbur/s1 h[ev]1 appe> to h occurr$ 9 ,triassic times 9 ,devon%ire4 ,b 9 o!r areas1 su* z ! ,tyrol1 ,s\?-ea/]n ,europe & ,we/]n ,am]ica1 ! ,triassic1 ,jurassic1 & ,cretace\s p]iods 7 m>k$ by gr& manife/ations ( volcanic activity4 ,! volcanic =ces :i* _h dur+ ! long ,mesozoic p]iods des]t$ our "p ( ! e>?'s surface1 appe> to h return$ to x 9 full rig\r 9 ! ,t]ti>y epo*4 ,9 ! ,new]-,palozoic p]iods ! direction ( ! great volcanic b& :i* trav]s$ our isl&s appe>s to h be5 f nor?-ea/ to s\?-we/2 b 9 ,t]ti>y times a new set ( fissures 7 op5$ runn+ f nor? to s\?4 ,!re is evid5ce t dur+ ! ,eoc5e or ,nummulitic p]iod1 ! fir/ indications ( ! subt]ranean =ces hav+ ga!r$ /r5g? bel[ ! di/rict 7 af=d$ by ! issue ( calc>e\s & silice\s spr+s1 & soon fissures 7 op5$ :i* emitt$ scori1 tuffs1 & lavas4 ,! int5sity ( ! volcanic action gradually increas$ till x atta9$ its maximum 9 ! ,mioc5e p]iod1 :5 a great *a9 ( volcanic m\nta9s /ret*$ nor? & s\? along ! l9e ( ! ,inn] ,hebrides1 ! nor?-ea/ ( ,irel&1 & ! sea :i* sep>ates ,great ,brita9 f ,irel&4 ,! basal-wrecks ( a numb] ( ^! volcanoes c be trac$ 9 ! isl&s ( ,skye1 ,mull1 ,rum1 & p>ts ( ! adjo9+ ma9l&4 ,we h already se5 t along ?is great b& ( volcanic action1 :i* trav]ses ! ,atlantic ,ocean f nor? to s\?1 a numb] ( active v5ts /ill exi/1 ?\gh _! en]gy is n[ f> less int5se ?an 0 ! case 9 =m] times4 ,! only ve/iges ( ! action ( ^! n[ decl9+ volcanic =ces1 at pres5t f\nd 9 our isl&s1 are ! hot spr+s ( ,ba? & a few o!r w>m & m9]al spr+s2 b 9 connection ) ?is subject x mu/ be rememb]$ t our c\ntry occasionally p>ticipates 9 great e>?quake-vibrations1 l t :i* de/roy$ ,lisbon 9 ! ye> #agei4 ,sid5ote3 ,,anci5t ,,volcanoes ,,9 ,,o!r ,,di/ricts4 ,if we 7 to /udy any o!r "p ( ! e>?'s surface1 we %\ld arrive at precisely ! same conclusion z ^? to :i* we h be5 conduct$ by our exam9ation ( ! ,briti% ,isl&s--namely1 t dur+ pa/ geological times ! subt]ranean =ces _h made !mselves felt 9 ! area1 _h gradually atta9$ a maximum1 & !n z gradually decl9$1 pass+ ?r\gh all ^? v>i$ cycles :i* we h describ$ 9 a =m] *apt]4 ,& we %\ld also f9d t ^! p]iods ( volcanic activity alt]nat$ ) o!r p]iods ( complete quiesc5ce :i* 7 ( long] or %ort] duration4 ,b on comp>+ two diff]5t di/ricts1 we %\ld discov] t :at 0 a p]iod ( volcanic activity 9 ! "o 0 a p]iod ( repose 9 ! o!r1 & vice v]s4 ,f ^! facts geologi/s h be5 l$ to ! conclusion :i* we h already enunciat$--namely1 t ! subt]ranean =ces are 9 a /ate ( cont9ual flux ov] ! surface ( ! globe4 ,at "o po9t ( ! e>?'s cru/ ^! =ces gradually ga!r su* en]gy z to r5d asund] ! sup]9cumb5t rock-masses & make !mselves manife/ at ! surface 9 ! s]ies ( ph5om5a *>act]i/ic ( volcanic action4 ,b aft] a long] or %ort] int]val ( "t--an int]val :i* mu/ probably be measur$ by millions ( ye>s--! volcanic =ces die out 9 t area to make _! appe>ance 9 ano!r4 ,h5ce1 al?\gh we may n be able to prove ! fact by any ma!matical demon/ration1 a /rong presumption is rais$ 9 fav\r ( ! view t ! subt]ranean en]gy 9 ! e>?'s cru/ is a con/ant quantity1 & t ! only v>iations :i* take place are 9 ! locality ( its manife/ation4 ,^u ?is "q :e!r ! am\nt ( ?is subt]ranean en]gy )9 ! e>?'s cru/ is at ! pres5t "t increas+1 /ation>y1 or decl9+1 we are n altoge!r de/itute ( evid5ce4 ,!re are "s consid]ations connect$ ) c]ta9 a/ronomical hypo!ses1 to :i* we %all h]eaft] h to ref]1 t might lead u to ent]ta9 ! view t ! subt]ranean activity 0 once f> great] ?an x is at pres5t1 & t dur+ ! long p]iods ( ! e>?'s pa/ hi/ory x has be5 sl[ly & gradually decl9+4 ,& ^? :o exam9e ! va/ masses ( igne\s mat]ials :i* h be5 p\r$ out f volcanic v5ts dur+ ! e>li] p]iods ( ! e>?'s hi/ory may be incl9$1 at fir/ sight1 to po9t to !m z af=d+ conclusive pro( ( ?is gradual decl9e4 ,sid5ote3 ,,suppos$ ,,decl9e ,,( ,,volcanic ,,action4 ,b a m c>eful /udy ( ! rocks 9 "q w probably cause a geologi/ to pause be=e jump+ to su* a conclusion4 ,if we look at ! va/ masses ( volcanic mat]ials erupt$ 9 ,mioc5e times 9 our own isl& & 9 ,irel&1 = example1 we might be l$ to imag9e t we h ! indications ( a v]itable ',reign ( ,fire1' & t ! evid5ce po9ts to a condition ( ?+s v diff]5t inde$ f t :i* prevails at ! pres5t day4 ,b 9 arriv+ at su* a conclusion we %\ld be neglect+ a mo/ important consid]ation1 ! disreg>d ( :i* has be5 ! f]tile p>5t ( _m geological errors4 ,_m indep5d5t l9es ( evid5ce all po9t to ! inf]5ce t ^! volcanic ejections are n ! result ( "o viol5t ef=t1 b are ! product ( num]\s small outbreaks :i* h be5 scatt]$ ov] enorm\s p]iods ( "t4 ,:5 we exam9e ) due c>e ! lavas1 tuffs1 & o!r volcanic ejections :i* con/itute su* m\nta9-masses z ^? ( ! ,hebrides1 ( ! ,auv]gne1 & ( ,hung>y1 we f9d cle> pro(s t ! anci5t ,mioc5e volcanoes ( ^! di/ricts 7 clo!d ) luxuriant =e/s1 ?r\gh :i* wild animals roam$ 9 ! greate/ abundance4 ,! int]vals betwe5 ! ejections ( successive lava-/reams 7 (t5 s great1 t soils 7 =m$ on ! m\nta9-slope1 & /reams cut deep rav9es & valleys 9 !m4 ,! isl& ( ,java is situat$ ne> ! v he>t ( :at is at ! pres5t day ! mo/ active volcanic c5tre on ! face ( ! globe1 yet vegetable & animal life fl\ri% luxuriantly !re1 & ! isl& is "o ( ! ri*e/ & mo/ f]tile spots ^u ! face ( ! globe4 ,n all ! t]rors ( occasional volcanic outbreaks w ev] drive ! ,neapolitan v9e-dress]s f ! f]tile slopes ( ,vesuvius1 = its p]iods ( repose are long1 & its eruptions are ( %ort duration4 ,^! consid]ations lead ! geologi/ to conclude t ! evid5ce af=d$ by ! anci5t volcanic rocks is cle> & positive 9 support ( ! view t ! manife/ations ( ! subt]ranean =ces 9 ! pa/ agree precisely 9 _! nature & 9 _! products ) ^? tak+ place ar\nd u at ! pres5t "t4 ,on ! "q ( great secul> *anges hav+ occurr$ 9 ! am\nt ( volcanic en]gy 9 pa/ geological p]iods1 ! evid5ce mu/ be pron\nc$ negative1 or at ! be/ d\btful4 ,b ev5 if ! geologi/ confesses himself unable to e/abli% ! fact ( any decl9e 9 ! subt]ranean en]gies dur+ ! va/ p]iods ( :i* he takes cognisance1 x mu/ be rememb]$ t su* decl9e may really be go+ on2 = va/ z 0 ! duration ( ! geological epo*s1 !y probably con/itute b a fraction ( ^? f> gr&] p]iods :i* are requir$ by ! speculations ( ! physical a/ronom]4 ,,*apt] ,x4 ,,! ,,"p ,,play$ ,,by ,,volcanoes ,,9 ,,! ,,economy ,,( ,,nature4 ,! fir/ impression :i* is produc$ ^u ! m9d1 :5 ! ph5om5a ( volcanic action are /udi$1 is t "h we h exhibitions ( de/ructive viol5ce ! effects ( :i* mu/ be entirely mis*iev\s & disa/r\s to ! liv+ be+s occupy+ ! e>?'s surface4 ,a little consid]ation w conv9ce u1 h[ev]1 t ! gr& & t]rible "* ( ! displays ( volcanic en]gy h giv5 rise to exagg]at$ notions conc]n+ _! de/ructive effects4 ,! fact t di/ricts situat$ ov] ! mo/ p[]ful volcanic foci1 l ,java & ,japan1 are luxuriant 9 _! productions1 & ?ickly inhabit$1 may well lead u to pause ere we condemn volcanic action z productive only ( mis*ief to ! liv+ be+s on ! e>?'s surface4 ,! actual slopes ( ,vesuvius & ,etna1 & _m o!r active volcanoes1 are abundantly clo!d ) v9ey>ds & =e/s & are ?ickly /udd$ ) popul\s villages4 ,z a matt] ( fact1 ! actual am\nt ( damage to life & prop]ty :i* is effect$ by volcanic eruptions is small4 ,usually1 ! inhabitants ( ! di/rict h suffici5t w>n+ to enable !m to escape ) _! lives & to c>ry away _! mo/ valuable possessions4 ,& ?\gh f]tile tracts are cov]$ by loose du/ & a%es1 or by lava- & mud-curr5ts1 yet ! /]ility ?us produc$ is g5]ally ( %ort duration1 = by _! decomposition volcanic mat]ials give rise to ! =mation ( ! ri*e/ & mo/ productive soils4 ,e>?quakes1 z we h already se51 are f> m de/ructive 9 _! effects ?an are volcanoes4 ,h\ses & villages1 nay ev5 entire cities1 are1 by vibrations ( portions ( ! e>?'s cru/1 r$uc$ to heaps ( ru9s1 & fam9es & pe/il5ces too frequ5tly foll[1 z ! consequ5ce ( ! disorganisation ( our social sy/ems by ^! t]rible cata/rophes4 ,x may well be d\bt$1 h[ev]1 :e!r ! annual av]age ( de/ruction to life & prop]ty caus$ by all k9ds ( subt]ranean action1 exce$s t produc$ ei!r by floods or by hurricanes4 ,yet we "k t ! circulation ( wat] & air ov] our globe are b5eficial & necess>y op]ations1 & t ! mis*ief occasionally wr\ght by ! mov+ bodies ( wat] & air is q insignificant comp>$ ) ! good :i* !y effect4 ,9 ! same way1 we %all be able to %[ t ! subt]ranean en]gies are necess>y to ! cont9u$ exi/5ce ( our globe z a place fitt$ = ! habitation ( liv+ be+s1 & t ! mis*iev\s & de/ructive effects ( ^! en]gies be> b a small & insignificant proportion to ! b5eficial results ) :i* !y mu/ be cr$it$4 ,sid5ote3 ,,levell+ ,,action ,,( ,,d5ud+ ,,=ces4 ,we h _h frequ5t occasion 9 ! prec$+ pages to ref] to ! "w--sl[ b sure1 sil5t b effective--wr\ght by ! action ( ! d5ud+ =ces ev] op]at+ ^u ! surface ( our globe4 ,! wat]s cond5s+ f ! atmosph]e & fall+ ^u ! l& 9 ! =m ( ra91 sn[1 or hail1 are *>g$ ) small quantities ( dissolv$ gases1 & ^! wat]s p5etrat+ among ! rock-masses ( :i* ! e>?'s cru/ is compos$1 give rise to v>i\s *emical actions ( :i* we h already notic$ su* rem>kable illu/rations 9 /udy+ ! anci5t volcanic products ( our globe4 ,by ?is action ! h>de/ & mo/ solid rock-masses are r$uc$ to a /ate ( complete dis9tegration1 c]ta9 ( _! +r$i5ts und]go+ decomposition1 & ! cem5t+ mat]ials :i* hold _! p>ticles toge!r be+ remov$ 9 a /ate ( solution4 ,9 ! high] regions ( ! atmosph]e ?is "w ( rock-dis9tegration proce$s ) ! greate/ rapidity2 = !re ! *emical action is re9=c$ by ! p[]ful me*anical action ( freez+ wat]4 ,on high m\nta9-peaks ! "w ( break+ up rock-masses goes on at ! mo/ rapid rate1 & e craggy p9nacle is swa!d by ! heaps ( fragm5ts :i* h fall5 f x4 ,! ,alp9e travell] ju/ly dreads ! cont9ual fusillade ( fall+ rock-fragm5ts :i* is kept up by ! ev]-active p[] ( ! fro/ 9 ^! high] regions ( ! atmosph]e2 & fe>s le/ ! vibrations ( 8 foot/eps %\ld loos51 f _! position ( prec>i\s re/1 ! rapidly accumulat+ piles ( detritus4 ,no m\nta9-peak atta9s to any v great elevation above ! e>?'s surface1 = ! high] we rise 9 ! atmosph]e ! great] is ! range ( temp]ature & ! m de/ructive are ! effects ( ! atmosph]ic wat]4 ,! moon1 :i* is a mu* small] planet ?an our e>?1 has m\nta9s ( f> great] elevation2 b ! moon possesses nei!r an atmosph]e nor moi/ure on its surface1 to produce ^? levell+ effects :i* we see ev]y:]e go+ on ar\nd u ^u ! e>?4 ,! dis9tegrat$ mat]ials1 produc$ by *emical & me*anical actions ( ! atmosph]ic wat]s ^u rock-masses1 are by floods1 riv]s1 & glaci]s1 gradually transport$ f high] to l[] levels2 & soon] or lat] e fragm5t1 :5 x has once be5 sep>at$ f a m\nta9-top1 mu/ rea* ! ocean1 :]e ^! mat]ials are accumulat$ & arrang$ to =m new rocks4 ,ov] e "p ( ! e>?'s surface ^! ?ree gr& op]ations ( ! dis9tegration ( old rock-masses1 ! transport ( ! mat]ials s produc$ to l[] levels1 & ! accumulation ( ^! mat]ials to =m new rocks1 is cont9ually go+ on4 ,x is by ! v>i$ action ( ^! d5ud+ ag5ts ^u rocks ( unequal h>dness1 occupy+ diff]5t positions 9 relation to "o ano!r1 t all ! ext]nal features ( hills1 & pla9s1 & m\nta9s owe _! orig94 ,x is a fact1 :i* is capable ( ma!matical demon/ration1 t by ! action ( ^! d5ud+ =ces ! surface ( all ! l&s ( ! globe is be+ gradually b surely l[]$2 & ?is takes place at su* a rate t 9 a few millions ( ye>s ! :ole ( ! exi/+ cont95ts mu/ be wa%$ away & _! mat]ials di/ribut$ ov] ! b$s ( ! oceans4 ,sid5ote3 ,,necessity ,,= ,,comp5sat+ ,,ag5cies4 ,x is evid5t t !re exi/s "s ag5cy by :i* ?is levell+ action ( ! d5ud+ =ces ( ! globe is comp5sat$2 & a little consid]ation w %[ t su* comp5sat+ ag5cy is f\nd 9 ! subt]ranean =ces ev] at "w )9 ! e>?'s cru/4 ,! effects ( ^! subt]ranean =ces :i* mo/ p[]fully arre/ our att5tion are volcanic outbur/s & e>?quake %ocks1 b a c>eful /udy ( ! subject proves t ^! are by no means ! mo/ important ( ! results ( ! action ( su* =ces4 ,exact obs]vation has prov$ t almo/ e "p ( ! e>?'s surface is ei!r ris+ or fall+1 & ! /rik+ & de/ructive ph5om5a ( volcanoes & e>?quakes probably be> only ! same relation to ^? gr& & useful actions ( ! subt]ranean =ces1 :i* floods d to ! sy/em ( circulat+ wat]s1 & hurricanes to ! sy/em ( mov+ air-curr5ts4 ,if we ride 9 a well-appo9t$ c>riage ) good spr+s1 ^u a railway :i* is 9 excell5t ord]1 ! movem5t is almo/ imp]ceptible to u2 & ! rate ( spe$ may be increas$ indef9itely1 )\t mak+ itself app>5t to our s5ses4 ,! smalle/ imp$im5t to ! ev5ness ( ! movem5t--su* z t produc$ by a small object plac$ ^u ! rails--at once makes itself felt by a viol5t j> & vibration4 ,h[ p]fectly ins5sible we may be ( ! gr&e/ & mo/ rapid movem5ts is taught u by ! facts demon/rat$ by ! a/ronom]4 ,by ! e>?'s daily rotation1 we are borne along at a rate :i* 9 "s places am\nts to ov] #a1jjj miles an h\r2 & by its annual revolution we are e h\r transport$ ?r\gh a di/ance ( #gj1jjj miles2 yet conc]n+ ! fact & direction ( ^! movem5ts we are :olly unconsci\s4 ,9 ! case bo? ( ! railway tra9 & ( our planet1 we c only e/abli% ! reality ( ! movem5t1 & its direction & rate1 by means ( obs]vations ^u ext]nal objects1 :i* appe> to u to h a movem5t 9 ! opposite direction4 ,9 ! same way we c only e/abli% ! fact ( ! movem5t ( portions ( ! e>?'s cru/ by notic+ ! *ang+ positions ( p>ts ( ! e>?'s surface 9 relation to ! con/ant level ( ! ocean4 ,:5 ?is is done we f9d abundant pro( t :ile "s p>ts ( ! e>?'s cru/ are ris+1 o!rs are z und\bt$ly und]go+ depression4 ,sid5ote3 ,,pot5cy ,,( ,,! ,,subt]ranean ,,=ces4 ,we %all be able to =m "s idea ( ! va/ness ( ! effects produc$ by ! subt]ranean =ces1 by a v simple consid]ation4 ,x is c]ta9 t dur+ ! enorm\s p]iods ( "t ( :i* ! records h be5 discov]$ by ! geologi/1 !re h always be5 cont95ts & oceans ^u ! e>?'s surface1 j z at pres5t1 & x is almo/ equally c]ta9 t ! proportions ( ! e>?'s surface occupi$ by l& & wat] respectively1 h n v>i$ v widely f ^? :i* n[ prevail4 ,b1 at ! same "t1 x is an equally well-e/abli%$ bet t ! d5ud+ =ces ev] at "w ^u ! e>?'s surface w\ld h be5 compet5t to ! removal ( exi/+ cont95ts _m times ov]1 9 ! va/ p]iods cov]$ by geological records4 ,h5ce we are driv5 to conclude t ! subt]ranean movem5ts h 9 pa/ times entirely comp5sat$ = ! wa/e produc$ by ! d5ud+ =ces ev] at "w ^u our globe4 ,b ?is is n all4 ,! subt]ranean =ces n only produce upheaval2 9 a great _m cases ! evid5ces ( subsid5ce are z cle> & conclusive z are ^? ( upheaval 9 o!rs4 ,h5ce we are driv5 to conclude t ! =ces produc+ upheaval ( portions ( ! e>?'s cru/ are suffici5t1 n only to balance ^? produc+ subsid5ce1 b also to comp5sate = ! de/ructive action ( d5ud+ ag5ts ^u ! l&-masses ( ! globe4 ,x is only by a c>eful & att5tive /udy & calculation ( ! effects produc$ by ! d5ud+ ag5ts at "w all ar\nd u1 aid$ by an exam9ation ( ! enorm\s ?icknesses ( /rata =m$ by ! action ( su* causes dur+ pa/ geological times1 t we are able to =m any idea ( ! reality & va/ness ( ! ag5ts ( *ange :i* are ev] op]at+ to modify ! e>?'s ext]nal features4 ,:5 we h cle>ly realis$ ! gr& effects produc$ on ! surface ( ! globe by ^! ext]nal =ces1 ?r\gh ! action ( its inve/+ atmosph]e & circulat+ wat]s1 !n1 & only !n1 %all we be 9 a position to e/imate ! f> great] effects result+ f ! int]nal =ces1 ( :i* ! mo/ /rik+1 b n ! mo/ important1 results are se5 9 ! production ( volcanic eruptions & e>?quake-%ocks4 ,ano!r s]ies ( facts :i* s]ve to conv9ce ! geologi/ ( ! reality & pot5cy ( ! =ces ev] at "w )9 ! e>?'s cru/1 & ! way 9 :i* ^! h op]at$ dur+ pa/ geological p]iods1 is f\nd 9 ! di/urb$ condition ( _m ( ! /ratifi$ rock-masses ( :i* x is compos$4 ,su* /ratifi$ rock-masses1 x is cle>1 mu/ h be5 orig9ally deposit$ 9 a position ( approximate horizontality2 b !y are n[ (t5 f\nd 9 incl9$ & ev5 v]tical positions2 !y are se5 to be b5t1 crumpl$1 puck]$1 & fold$ 9 ! mo/ rem>kable mann]1 & h n unfrequ5tly be5 brok5 across by dislocations--'faults'--:i* h sometimes displac$ masses1 orig9ally 9 contact1 to ! ext5t ( ?\s&s ( feet4 ,! slate-rocks ( ! globe1 moreov]1 be> witness to ! fact t /rata h be5 subject$ to ! action ( lat]al compression ( enorm\s viol5ce & va/ duration2 :ile 9 ! metamorphic rocks we see ! effects ( /ill m extreme me*anical /ra9s1 :i* h be5 9 "p trans=m$ into *emical action4 ,no "o :o has n /udi$ ! cru%$1 crumpl$1 fractur$1 & alt]$ condition ( _m ( ! s$im5t>y rocks ( ! globe1 c =m ! fa9te/ idea ( ! enorm\s effects ( ! int]nal =ces :i* h be5 9 op]ation )9 ! e>?'s cru/ dur+ e>li] geological p]iods4 ,& x is only by su* /udies z ^! t we at la/ le>n to reg>d ! e>?quake & volcanic ph5om5a ( our globe1 n z ! gr&e/ & mo/ important effects ( ^! =ces1 b z _! second>y & accid5tal accompanim5ts4 ',volcanoes1' x has be5 said1 'are ! safety-valves ( ! globe2' & :5 we come to realise ! real ext5t & nature ( ! int]nal =ces ceaselessly work+ 9 ! e>?'s cru/ we %all sc>cely be dispos$ to reg>d ! simile z an ov]/ra9$ "o4 ,sid5ote3 ,,relation ,,to ,,cont95tal ,,movem5ts4 ,! fir/ geologi/ :o attempt$ to %[ ! exact relations exi/+ betwe5 ^? subt]ranean =ces :i* cause ! movem5ts ( cont95tal masses ( l&1 & ^? m />tl+ displays ( en]gy :i* are witness$ 9 volcanic outbur/s1 0 ! late ,mr4 ,p\lett ,scrope4 ,at a some:at lat] date ,mr4 ,d>w91 9 8 rem>kable pap] ',on ! ,connexion ( c]ta9 ,volcanic ,ph5om5a 9 ,s\? ,am]ica1 & on ! ,=mation ( ,m\nta9-*a9s & ,volcanoes z ! effect ( ,cont95tal ,elevations1' ?rew mu* new & important light ^u ! "q4 ,:ile1 on ! "o h&1 we are l$ by rec5t geological inve/igations to reject ! notions :i* 7 =m]ly accept$1 by :i* m\nta9-ranges 7 suppos$ to be sudd5ly & viol5tly upheav$ by volcanic =ces1 we are1 on ! o!r h&1 driv5 to conclude t )\t ! action ( ^! subt]ranean =ces1 ! irregul>ities :i* are exhibit$ on ! e>?'s surface c\ld n h _h any exi/5ce4 ,x is true t ! actual =ms ( ! m\nta9-ranges are due directly to ! action ( d5ud+ =ces1 :i* h sculptur$ out f ! rude rocky masses all ! v>i$ outl9es ( peaks & crags1 ( rav9es & valleys4 ,b x is none ! less true t ! det]m9+ causes :i* h direct$ & controll$ all ?is e>?-sculpture1 are f\nd 9 ! relative positions ( h>d & s(t masses ( rock2 b ^! rock-masses h acquir$ _! h>dness & consi/5cy1 & h assum$ _! pres5t positions1 9 ob$i5ce to ! action ( subt]ranean =ces4 ,h5ce we see t ?\gh ! =mation ( m\nta9-ranges is proximately due to ! d5ud+ =ces1 :i* h sculptur$ ! e>?'s surface1 ! prim>y cause = ! exi/5ce ( su* m\nta9-*a9s mu/ be s\ght = 9 ! fact t subt]ranean =ces h be5 at "w1 fold+1 crumpl+1 & h>d5+ ! s(t s$im5ts1 & plac+ !m 9 su* positions t1 by ! action ( d5udation1 ! m indurat$ portions are left /&+ z m\nta9-masses above ! g5]al surface4 ,! old notion t m\nta9-*a9s are due to a v]tical up?ru/ f bel[1 f9ds b little support :5 we come to /udy ) due c>e ! positions ( ! rock-masses compos+ ! e>?'s cru/4 ,on ! contr>y1 we f9d t m\nta9-ranges are usually c>v$ out ( ! cru%$ & crumpl$ edges ( /rata :i* h along c]ta9 l9es be5 influ5c$ by great me*anical /ra9s1 & subject$ to m or less induration & *emical alt]ation4 ,:5 we comp>e ^! fold$ & contort$ portions ( ! /rata ) ^? p>ts ( ! same b$s :i* are n s affect$1 we f9d ! effects produc$ 9 ! =m] are n su* z w\ld result f an up?ru/ f bel[1 b f movem5ts by :i* a tang5tial /ra9 w\ld be br\ght ab\t4 ,if we imag9e c]ta9 l9es ( weakness to exi/ 9 ! solid cru/ ( ! e>?1 !n any movem5ts 9 ! portions ( ! cru/ betwe5 ^! l9es ( weakness w\ld cause cru%+ & crumpl+ ( ! /rata along ! latt]4 ,sid5ote3 ,,=mation ,,( ,,m\nta9-,,*a9s4 ,rec5t inve/igations ( ,dana & o!r au?ors h ?r[n mu* new light ^u ! "q ( ! mode ( =mation ( m\nta9-*a9s1 & ! relation betwe5 ! movem5ts by :i* !y are produc$ & ! sudd5 & viol5t manife/ations ( =ce witness$ 9 volcanic outbur/s4 ,we _c1 p]haps1 bett] illu/rate ?is subject ?an by giv+ a sket* ( ! s]ies ( op]ations to :i* ! great ,alp9e *a9s owe _! orig94 ,!re are good gr\nds = believ+ t ! great m\nta9-axis ( ,s\!rn ,europe1 ) its cont9uation 9 ,asia1 _h no exi/5ce dur+ ! e>li] geological p]iods4 ,inde$1 x has be5 prov$ t all ! high] among ! exi/+ m\nta9-*a9s ( ! globe h be5 almo/ entirely =m$ 9 ,t]ti>y times4 ,! reason ( ?is rem>kable fact is n f> to seek4 ,s rapid is ! "w ( d5udation 9 ! high] regions ( ! atmosph]e1 t ! elevat$ crags & p9nacles are be+ brok5 up by ! action ( moi/ure & fro/ at an exce$+ly rapid rate4 ,?is fact is atte/$ by ! exi/5ce ( ^? enorm\s masses ( angul> rock-fragm5ts :i* are f\nd lodg$ on e vantage-gr\nd among ! m\nta9-summits1 z well z by ! cont9ually desc5d+ mat]ials :i* are borne by glaci]s & m\nta9-torr5ts to ! valleys bel[4 ,:]e su* a rate ( dis9tegration z ?is is ma9ta9$1 no elevat$ m\nta9-cre/s c\ld exi/ ?r\gh long geological p]iods4 ,x is true we f9d 9 all p>ts ( ! globe relics ( _m m\nta9-*a9s :i* 7 =m$ be=e ! ,t]ti>y p]iod2 b ^! h by long-cont9u$ d5udation be5 worn d[n to 'm]e /umps4' ,( su* worn-d[n & degrad$ m\nta9-ranges we h examples 9 ! ,sc&9avian *a9s1 & "s ( ! l[ m\nta9-regions ( ,c5tral ,europe & ,nor? ,am]ica4 ,let u n[ proce$ to illu/rate ?is subject by briefly sket*+ ! hi/ory ( t s]ies ( op]ations by :i* ! great m\nta9-*a9s ( ! ,alp9e sy/em h be5 =m$4 ,! fir/ /age ( t gr& s]ies ( op]ations appe>s f rec5t geological rese>*es to h consi/$ 9 ! op5+ ( a numb] ( fissures runn+ along a l9e ne> to t at :i*1 9 a long subsequ5t p]iod1 ! elevation ( ! m\nta9-masses took place4 ,?is betrayal ( ! exi/5ce ( a l9e ( weakness 9 ?is "p ( ! e>?'s cru/ occurr$ 9 ! ,p]mian p]iod1 & f t "t onw>d a s]ies ( wond]ful movem5ts & *anges h be5 go+ =w>d1 :i* h result$ 9 ! production ( ! ,alp9e *a9s z we n[ see !m4 ,sid5ote3 ,,volcanic ,,fissures ,,( ,,p]mian ,,p]iod4 ,f ! great fissures op5$ 9 ,p]mian times along ?is l9e ( weakness1 great quantities ( lava1 scori1 & tuff 7 p\r$ out1 & ^! accumulat$ to =m great volcanic m\nta9s1 :i* we c n[ only /udy at a few isolat$ spots1 z 9 ! ,tyrol1 ,c>9?ia1 & ab\t ,lake ,lugano4 ,ev]y:]e else1 ^! ,p]mian volcanic rocks appe> to be deeply buri$ "u ! lat]-=m$ s$im5ts1 f :i* ! ,alp9e *a9s h be5 c>v$4 ,few & imp]fect1 h[ev]1 z are ! exposures ( ^! anci5t rhyolite & qu>tz-&esite lavas & agglom]ates =m$ at ! close ( ! ,palozoic epo*1 _! greatly d5ud$ relics =m masses :i* are 9 places m ?an #i1jjj feet 9 ?ickness4 ,f ?is fact we are able to =m "s slight idea ( ! scale ^u :i* ! volcanic outbur/s 9 "q mu/ h tak5 place dur+ ,p]mian times4 ,! second /age 9 ! s]ies ( op]ations by :i* ! ,alp9e *a9s h be5 =m$1 consi/$ 9 a g5]al s9k+ ( ! surface along t l9e ( weakness 9 ! e>?'s cru/1 ! exi/5ce ( :i* _h be5 betray$ by ! =mation ( fissures & ! eruption ( volcanic rocks4 ,we h already _h occasion to rem>k h[ frequ5tly su* subsid5ces foll[ ^u ! extrusion ( volcanic masses at any "p ( ! e>?'s surface2 & we h ref]r$ ^! d[nw>d movem5ts 9 "p to ! removal ( support f bel[ ! portion ( ! cru/ affect$1 & 9 "p to ! weight ( ! mat]ials pil$ ^u its surface by ! volcanic =ces4 ,! volcanic en]gy :i* _h be5 manife/$ ) su* viol5ce dur+ ! ,p]mian p]iod1 does n appe> to h di$ out altoge!r dur+ ! succe$+ ,triassic p]iod4 ,a numb] ( small] volcanic v5ts 7 op5$ f "t to "t1 & f ^!1 lavas1 tuffs1 & agglom]ates1 *iefly ( basic composition1 7 p\r$ out4 ,! relics ( ^! old ,triassic volcanoes are f\nd at _m po9ts along ! ,alp9e *a91 b x is evid5t t ! igne\s =ces 7 gradually becom+ exhau/$ dur+ ?is p]iod1 & be=e ! close ( x !y _h fall5 into a /ate ( complete ext9ction4 ,b ! great subsid5ce :i* _h comm5c$ 9 ! ,triassic p]iod1 along :at 0 to become ! future l9e ( ! ,alp9e *a91 0 cont9u$ almo/ )\t int]ruption dur+ ! ,rhtic1 ! ,jurassic1 ! ,ti?onian1 ! ,neocomian1 ! ,cretace\s & ! ,nummulitic p]iods4 ,) respect to ! /rata =m$ dur+ all ^! p]iods1 x is f\nd t _! ?iknesses1 :i* away f ! ,alp9e axis may be measur$ by hundr$s ( feet1 is along t axis increas$ to ?\s&s ( feet4 ,! unit$ ?ickness ( s$im5ts accumulat$ along ?is great l9e ( subsid5ce betwe5 ! ,p]mian & ,nummulitic p]iods probably exce$s #fj1jjj feet1 or t5 miles4 ,! subsid5ce appe>s to h be5 v sl[ & gradual1 b almo/ un9t]rupt$1 & ! deposition ( s$im5ts seems to h kept pace ) ! s9k+ ( ! sea-bottom1 a fact :i* is prov$ by ! circum/ance t ne>ly ! :ole ( ^! s$im5ts 7 su* z mu/ h be5 accumulat$ 9 comp>atively %all[ wat]4 ,sid5ote3 ,,=mation ,,( ,,alp9e ,,geosyncl9al4 ,by ! means we h describ$ !re 0 ?us =m$ a 'geosyncl9al1' z geologi/s h call$ x1 t is1 a tr\gh-l holl[ fill$ ) masses ( abnormally ?ick5$ s$im5ts1 :i* _h be5 pil$ "o ^u ano!r dur+ ! long p]iods ( "t 9 :i* almo/ un9t]rupt$ subsid5ce 0 go+ on along ! ,alp9e l9e ( weakness 9 ! e>?'s cru/4 ,9 ?is way 0 br\ght toge!r t enorm\s accumulation ( mat]ials f :i* ! h>d masses ( ! ,alp9e *a9s 7 subsequ5tly elaborat$1 & out ( :i* ! m\nta9-peaks 7 ev5tually c>v$ by d5udation4 ,! ?ird /age 9 ?is gr& "w ( m\nta9-mak+ comm5c$ 9 ! ,oligoc5e p]iod4 ,x consi/$ ( a s]ies ( movem5ts affect+ ! p>ts ( ! e>?'s cru/ on ei!r side ( ! l9e ( weakness :i* _h fir/ exhibit$ itself 9 ,p]mian times4 ,by ^! movem5ts a s]ies ( tang5tial /ra9s 7 produc$1 :i* result$ 9 ! viol5t cru%+1 fold+1 & crumpl+ ( ! s$im5t>y mat]ials compos+ ! geosyncl9al4 ,"o effect ( ?is action 0 ! viol5t flexure & frequ5t fracture ( ^! /ratifi$ masses1 :i* are n[ f\nd 9 ! ,alp9e regions assum+ ! mo/ abnormal & unexpect$ positions & relations to "o ano!r4 ,sometimes ! /rata are f\nd tortur$ & twi/$ into ! mo/ complicat$ folds & puck]+s2 at o!rs !y are se5 to be completely inv]t$1 s t ! old] b$s are f\nd ly+ ^u ! new]2 & 9 o!rs1 aga91 great masses ( /rata h be5 trav]s$ by num]\s fractures or faults1 ! rocks on ei!r side ( :i* are displac$ to ! ext5t ( ?\s&s ( feet4 ,ano!r effect ( ! great lat]al ?ru/s by :i* ! ?ick s$im5t>y masses ( ! geosyncl9al 7 be+ s viol5tly di/urb$1 0 ! production ( a great am\nt ( induration & *emical *ange 9 ^! rocks4 ,masses ( s(t clay1 ( ! age ( t ^u :i* ,london is built1 7 by viol5t pressure r$uc$ to ! condition ( ro(+-slate1 simil> to t ( ,nor? ,wales4 ,"o ( ! mo/ important discov]ies ( mod]n times is t :i* has result$ 9 ! recognition ( ! fact ( ! mutual conv]tibility ( diff]5t k9ds ( en]gy4 ,we n[ "k t me*anical =ce may be trans=m$ into heat-=ce or *emical =ce2 & ( su* trans=mations we f9d abundant illu/rations 9 ! cru%$ & crumpl$ rock-masses ( ! ,alp9e *a9s4 ,"u ! influ5ce ( ^! sev]al k9ds ( =ce1 n only 0 extreme consolidation & induration produc$ among ! rock-masses1 b *emical aff9ity & cry/all9e action _h ! fulle/ play among ! mat]ials ( :i* !y 7 compos$4 ,9 _m cases we f9d ! orig9ally s(t muds1 s&s1 & %ell-banks conv]t$ into ! mo/ highly cry/all9e rocks1 :i* reta9 _! prim>y *emical composition1 b h entirely lo/ all _! o!r orig9al features4 ,sid5ote3 ,,=mation ,,( ,,alp9e ,,geanticl9al4 ,to ! mass ( fold$1 crumpl$1 & alt]$ /rata1 =m$ f a geosyncl9al by lat]al pressure1 geologi/s h giv5 ! "n ( a 'geanticl9al4' ,! =mation ( ! ,alp9e geanticl9al 0 due to movem5ts :i* comm5c$ 9 ! ,oligoc5e p]iod1 atta9$ _! maximum 9 ! ,mioc5e1 & appe> to h decl9$ & almo/ altoge!r di$ out 9 ! ,plioc5e p]iod4 ,! movem5ts :i* result$ 9 ! cru%+ & crumpl+ ( ! ?ick5$ mass ( s$im5ts along ! ,alp9e l9e ( weakness1 also gave rise to ! =mation ( a s]ies ( fissures f :i* volcanic action took place4 ,^! fissures 7 n1 h[ev]1 =m$ along ! orig9al l9e ( weakness1 = ?is _h be5 /r5g!n$ & repair$ by ! deposition ( t5-miles' ?ickness ( s$im5ts ^u x1 b along new fissures op5$ 9 directions p>allel to ! orig9al l9es ( weakness1 & 9 areas :]e a mu* less consid]able am\nt ( deposition _h tak5 place s9ce ,p]mian times4 ,we h abundant evid5ce t1 j at ! p]iod :5 ^? great movem5ts 7 comm5c+ :i* result$ 9 ! =mation ( ! great ,alp9e & ,himalayan geanticl9al1 e>?-fissures 7 be+ op5$ ^u ei!r side ( ! latt] f :i* volcanic outbur/s took place4 ,at ! p]iod :5 ! mo/ viol5t m\nta9-=m+ movem5ts occurr$1 ^! fissures 7 9 _! mo/ active condition1 & at ?is "t two great volcanic belts /ret*$ ea/ & we/1 on ei!r side (1 & p>allel to1 ! great ,alp9e *a94 ,! ,nor!rn volcanic b& 0 =m$ by ! num]\s v5ts1 n[ all ext9ct1 9 ,auv]gne1 ,c5tral ,g]many1 ,bohemia1 & ,hung>y1 & 0 probably cont9u$ 9 ! volcanoes ( ! ,?ian ,%an & ,mant*\ria4 ,! ,s\!rn volcanic b& 0 =m$ by ! num]\s v5ts ( ! ,ib]ian & ,italian p59sulas1 & ! isl&s ( ! ,m$it]ranean1 & 7 cont9u$ to ! ea/w>d by ^? ( ,asia ,m9or1 ,arabia1 & ! ,nor? ,indian ,ocean4 ,z ! e>?-movem5ts :i* produc$ ! geanticl9al di$ away1 ! volcanic en]gy along ^! p>allel volcanic b&s di$ away at ! same "t4 ,9 /udy+ ! geology ( ,c5tral & ,s\!rn ,europe1 no fact comes out m /rik+ly ?an t ( ! syn*ronism betwe5 ! e>?-movem5ts by :i* ! geanticl9al ( ! ,alps 0 =m$1 & ! volcanic manife/ations :i* 7 exhibit$ along l9es ( fissure p>allel to t geanticl9al4 ,! e>?-movem5ts & ! volcanic outbur/s bo? comm5c$ 9 ! ,oligoc5e p]iod1 gradually atta9$ _! maximum 9 ! ,mioc5e1 & z sl[ly decl9$ 9 ! ,plioc5e4 ,sid5ote3 ,,sculptur+ ,,( ,,alps ,,by ,,d5udation4 ,! f\r? /age 9 ! great "w ( m\nta9-build+ 9 ! case ( ! ,alps consi/$ 9 ! op]ation ( ! d5ud+ =ces1 ! dis9tegrat+ action ( ra9 & fro/1 ! transport+ action ( riv]s & glaci]s1 by :i* ! ,alp9e peaks 7 gradually sculptur$ out ( ! indurat$ & alt]$ masses con/itut+ ! geanticl9al4 ,! action ( ?is f\r? /age w5t on to a great ext5t side by side ) t ( ! ?ird /age4 ,s soon z ! e>?-movem5ts _h br\ght ! subm]g$ s$im5t>y masses ( ! geosyncl9al "u ! action ( ! surface tides & curr5ts ( ! ocean1 m>9e d5udation w\ld comm5ce2 &1 z ! "w ( elevation w5t on1 ! rock-masses w\ld gradually be br\ght )9 ! rea* ( ^? m sil5tly-work+ b f> m effective ag5ts :i* are ev] op]at+ 9 ! high] regions ( ! atmosph]e4 ,x is impossible to say :at w\ld h be5 ! height ( ! ,alp9e *a9 if ! "w ( d5udation _h n to a great ext5t kept pace ) t ( elevation4 ,only ! h>d] & m cry/all9e masses h = ! mo/ "p escap$ de/ruction1 & /& up 9 high craggy summits2 :ile flank+ hills1 l ! well-kn[n ,rigi1 are ,be5 to be compos$ ( conglom]ates ?\s&s ( feet 9 ?ickness1 compos$ ( _! dis9tegrat$ mat]ials4 ,x is a rem>kable fact1 z %[+ h[ enorm\s 0 ! "w ( elevation d>+ ! =mation ( ! geanticl9al1 t "s ( ! y\nge/ & lea/ consolidat$ rocks ( ! ,nummulitic p]iod are /ill f\nd at a height ( #aa1jjj feet 9 ! ,alps1 & ( #af1jjj feet 9 ! ,himalaya4 ,f :at has be5 said1 x w be se5 t m\nta9-*a9s may be reg>d$ z cicatris$ w\nds 9 ! e>?'s solid cru/4 ,a l9e ( weakness fir/ betrays itself at a c]ta9 "p ( ! e>?'s surface by fissures1 f :i* volcanic outbur/s take place2 & ?us ! position ( ! future m\nta9-*a9 is det]m9$4 ,next1 subsid5ce dur+ _m millions ( ye>s p]mits ( ! accumulation ( ! raw mat]ials out ( :i* ! m\nta9-range is to be =m$2 subsequ5t e>?-movem5ts cause ^! raw mat]ials to be elaborat$ into ! h>de/ & mo/ cry/all9e rock-masses1 & place !m 9 elevat$ & fav\rable positions2 & la/ly1 d5udation sculptures f ^! h>d5$ rock-masses all ! v>i$ m\nta9 =ms4 ,?us ! "w ( m\nta9-mak+ is n1 z 0 =m]ly suppos$ by geologi/s1 ! result ( a simple upheav+ =ce1 b is ! outcome ( a long & complicat$ s]ies ( op]ations4 ,sid5ote3 ,,orig9 ,,( ,,o!r ,,m\nta9-,,*a9s4 ,! c>eful /udy ( o!r m\nta9-*a9s1 especially ^? ( ! ,am]ican cont95t1 has %[n t ! s]ies ( actions :i* we h describ$ z occurr+ 9 ! ,alps1 took place 9 ! same ord] 9 ! =mation ( all m\nta9-masses4 ,x is d\btful :e!r ! l9e ( weakness is always betray$ 9 ! fir/ in/ance by ! =mation along its c\rse ( volcanic fissures4 ,b 9 all cases we h evid5ce ( ! production ( a geosyncl9al1 :i* is aft]w>ds1 by lat]al pressure1 conv]t$ into a geanticl9al1 & f ?is ! m\nta9-*a9s h be5 c>v$ by d5udation4 ,pr(essor ,dana has %[n t ! geosyncl9al ( ! ,appala*ian *a9 0 made up ( s$im5ts atta9+ a ?ickness ( #dj1jjj feet1 or eight miles2 :ile ,mr4 ,cl>5ce ,k+ has %[n t a "p ( ! geosyncl9al ( ! ,rocky ,m\nta9s 0 built up ( no less ?an #fj1jjj feet1 or twelve miles ( /rata4 ,x has ?us be5 e/abli%$ t a v rem>kable relation exi/s betwe5 ! =ces by :i* cont95tal masses ( l& are rais$ & depress$1 & m\nta9-ranges h be5 develop$ along l9es ( weakness sep>at+ su* mov+ cont95tal masses1 & ^? m sudd5 & /rik+ manife/ations ( en]gy :i* give rise to volcanic ph5om5a4 ,x is 9 ?is relation betwe5 ! widespread subt]ranean en]gies & ! local developm5t ( ! same =ces at volcanic v5ts1 t we mu/ 9 all probability seek = ! explanation ( ^? int]e/+ peculi>ities ( ! di/ribution ( volcanoes ^u ! face ( ! globe :i* we h describ$ 9 a =m] *apt]4 ,! p>allelism ( volcanic b&s to great m\nta9-*a9s is ?us easily acc\nt$ =2 & 9 ! same way we may probably expla9 ! position ( mo/ volcanoes ) reg>d to coa/-l9es4 ,we h already po9t$ out ! objections to ! commonly-receiv$ view t volcanoes dep5d = _! supplies ( wat] on ! proximity ( ! ocean4 ,?is proximity ( ! ocean to volcanic v5ts we are ?us incl9$ to reg>d1 n z ! cause1 b z ! effect ( ! subt]ranean action4 ,! positions ( bo? volcanoes & coa/-l9es are det]m9$ by ! limits ( ^? great areas ( ! e>?'s cru/ :i* are subject$ to sl[ v]tical movem5ts1 (t5 9 opposite directions4 ,t]rible & /rik+1 !n1 z are ! ph5om5a connect$ ) volcanic action1 su* sudd5 & viol5t manife/ations ( ! subt]ranean en]gy mu/ n be reg>d$ z ! only1 or inde$ ! *ief1 effects :i* !y produce4 ,! int]nal =ces cont9ually at "w )9 ! e>?'s cru/ p]=m a s]ies ( mo/ important functions 9 connection ) ! economy ( ! globe1 & 7 ! action ( ^! =ces to die out1 our planet w\ld soon cease to be fit = ! habitation ( liv+ be+s4 ,!re is no fact :i* ! geological /ud5t is m con/antly call$ ^u to be> 9 m9d ?an t ( ! pot5cy ( seem+ly insignificant causes :i* cont9ue 9 con/ant op]ation ?r\gh long p]iods ( "t4 ,inde$ ^! small & almo/ unnotic$ ag5cies at "w ^u ! e>?'s cru/ are (t5 f\nd1 9 ! long ran1 to produce f> gr&] effects ?an ^? ( :i* ! action is mu* m /rik+ & obvi\s4 ,x is to ! sil5t & imp]ceptible action ( atmosph]ic moi/ure & fro/ t ! dis9tegration ( ! solid rock-masses mu/ be ma9ly ascrib$2 & ! noisy cat>act & ocean-bill[ produce effects :i* are q insignificant comp>$ ) ^? :i* mu/ be ascrib$ to ! slight & almo/ unnotic$ =ces4 ,great masses ( lime/one are built up ( ! rema9s ( microscopic organisms1 :ile ! l>g] & high] life-=ms contribute b little to ! great "w ( rock-build+4 ,sid5ote3 ,,effects ,,( ,,sl[ ,,cont95tal ,,movem5ts4 ,9 ! same way x is to ! almo/ unnotic$ action ( ! subt]ranean =ces 9 rais+ "s va/ areas ( ! e>?'s cru/1 9 depress+ o!rs1 & 9 br++ ab\t ! developm5t ( m\nta9-*a9s betwe5 !m1 t we mu/ ascribe a f> m important "p 9 ! economy ( our globe ?an to ! m conspicu\s b less con/ant action ( volcanoes4 ,a few simple consid]ations w s]ve to conv9ce u1 n only ( ! b5eficial effects ( ! action ( ! subt]ranean en]gies )9 ! e>?'s cru/1 b ( ! absolute necessity ( ! cont9u$ op]ation ( ^? en]gies to ! p]petuation ( t set ( conditions by :i* our planet is fitt$ to be ! habitation ( liv+ be+s4 ,we h already ref]r$ to ! prodigi\s effects :i* are con/antly be+ produc$ ar\nd u by ! action ( ! ext]nal =ces at "w ^u ! globe4 ,! s\rce ( ^! ext]nal =ces is f\nd 9 ! movem5ts & *anges :i* are ev] go+ on )9 ! aque\s & atmosph]ic m$ia 9 :i* ! globe is envelop$4 ,! circulation ( ! air1 influ5c+ ! circulation ( ! wat]s 9 ! %ape ( cl\ds1 ra91 sn[1 riv]s1 glaci]s1 & oceans1 causes ! break+ up ( ev5 ! h>de/ rock-masses1 & ! cont9ual removal ( _! dis9tegrat$ fragm5ts f high] to l[] levels4 ,?is "w goes on ) m or less regul>ity ov] e "p ( ! l& rais$ above ! level ( ! ocean1 b ! rate ( de/ruction 9 ! high] regions ( ! atmosph]e is f> m rapid ?an at l[] levels4 ,h5ce ! circulat+ air & wat] ( ! globe are f\nd to be cont9ually act+ z levell]s ( ! l&-masses ( ! e>?4 ,x is by no means a difficult task to calculate ! approximate rate at :i* ! v>i\s cont95ts & isl&s are be+ levell$ d[n1 & su* calculations prove t 9 a v few millions ( ye>s ! exi/+ =ces op]at+ ^u ! e>?'s surface w\ld r$uce ! :ole ( ! l&-masses to ! level ( ! ocean4 ,b a little consid]ation w conv9ce u t ! circulation ( ! air & wat]s ( ! globe are !mselves dep5d5t ^u ! exi/5ce ( ^? irregul>ities ( ! l&-surfaces :i* !y are con/antly t5d+ to de/roy4 ,)\t elevat$ m\nta9 ridges ! regul> cond5sation ( moi/ure1 & its collection & di/ribution 9 /reams & riv]s ov] e "p ( ! l& surfaces1 c\ld n take place4 ,"u ^! circum/ances ! un*eck$ evaporation ( ! oceanic wat]s w\ld probably g on1 till ! proportion ( wat]-vap\r increas$ to su* an ext5t 9 ! atmosph]e z effectually to de/roy ^? nicely-balanc$ conditions ^u :i* ! cont9u$ exi/5ce ( bo? vegetable & animal life dep5d4 ,b ! repeat$ upw>d & d[nw>d movem5ts :i* h be5 %[n to be go+ on 9 ! great l&-masses ( ! globe1 giv+ rise 9 turns to ^? lat]al ?ru/s & tang5tial /ra9s to :i* m\nta9-*a9s owe _! =mation1 af=d a p]fect comp5sation to ! action ( ! ext]nal =ces ev] op]at+ ^u ! e>?'s surface4 ,if1 h[ev]1 ! uncomp5sat$ effect ( ! ext]nal =ces act+ on ! e>?'s cru/ is calculat$ to br+ ab\t ! de/ruction ( ^? conditions ^u :i* ! exi/5ce ( life dep5ds1 ! uncomp5sat$ effect ( ! int]nal =ces act+ on ! e>?'s cru/ are fraught ) at lea/ equal dang]s to ^? necess>y conditions4 ,sid5ote3 ,,contra/ ,,betwe5 ,,! ,,e>? ,,& ,,moon4 ,9 our ne>e/ neighb\r among ! planets--! moon--! telescope has reveal$ to u ! exi/5ce ( a globe1 9 :i* ! int]nal =ces h n be5 *eck$ & controll$ by ! op]ation ( any ext]nal ag5cies--= ! moon appe>s to be de/itute ( bo? atmosph]e & wat]4 ,"u ^! circum/ances we f9d its surface1 z we might expect1 to be compos$ ( rocks :i* appe> to be entirely ( igne\s orig92 ! m\nta9-masses1 unworn by ra9 or fro/1 riv] or glaci]1 be+ ( mo/ prodigi\s dim5sions z comp>$ ) ^? ( our own globe1 :ile no features at all resembl+ valleys1 or pla9s1 or alluvial flats are any:]e to be disc]n$ ^u ! lun> surface4 ,b by ! admirable balanc+ ( ! ext]nal & int]nal =ces on our own globe1 ! conditions necess>y to animal & vegetable exi/5ce are almo/ con/antly ma9ta9$1 & ^? int]ruptions ( su* conditions1 produc$ by hurricanes & floods1 by volcanic outbur/s & e>?quakes1 may safely be reg>d$ z ! insignificant accid5ts ( :at is1 on ! :ole1 a v p]fectly work+ piece ( ma*9]y4 ,! anci5ts lov$ to lik5 ! e>? to a liv+ be+--! macrocosm ( :i* man 0 ! puny repres5tative or microcosm2 & :5 we /udy ! well-adapt$ int]play ( ! =ces at "w ^u ! e>?'s cru/1 bo? f )9 & )\t1 ! analogy seems a sc>cely /ra9$ "o4 ,9 ! macrocosm & ! microcosm alike1 slight int]f]5ces ) ! regul> functions occasionally take place1 & bo? ( !m exhibit ! traces ( a pa/ evolution & ! g]ms ( an ev5tual decay4 ,,*apt] ,,xi4 ,,:at ,,volcanoes ,,tea* ,,u ,,conc]n+ ,,! ,,nature ,,( ,,! ,,e>?',s ,,int]ior4 ,9 ent]+ ^u any speculations or enquiries conc]n+ ! nature ( ! int]ior ( our globe1 x is necess>y be=e all ?+s t we %\ld cle>ly realise 9 our m9ds h[ small & almo/ inf9itesimal is t "p ( ! e>?'s mass :i* c be subject$ to direct exam9ation4 ,! di/ance f ! surface to ! c5tre ( our globe is ne>ly #d1jjj miles1 b ! deepe/ m9es d n p5etrate to mu* m ?an half a mile f ! surface1 & ! deepe/ bor+s fall f> %ort ( a mile 9 dep?4 ,sometimes1 x is true1 ! geologi/ f9ds means = draw+ inf]5ces z to ! nature ( ! rocks at dep?s ( t5 or fifte5 miles bel[ ! surface2 b ! la/-nam$ dep? mu/ be reg>d$ z ! utmo/ limit ( t portion ( our globe :i* c be made ! object ( direct obs]vation & /udy4 ,?is ?9 ext]ior film ( ! e>?'s mass1 :i* ! geologi/ is able to inve/igate1 we call ! 'cru/ ( ! globe'2 b x mu/ be rememb]$ t 9 us+ ?is t]m1 x is n int5d$ to imply t ! out] "p ( our globe diff]s 9 any ess5tial respect f ! int]ior4 ,! t]m 'cru/ ( ! globe' is employ$ by geologi/s z a conv5i5t way ( ref]r+ to t portion ( ! e>? :i* is accessible to _! obs]vation4 ,b if we are unable to make direct inve/igations conc]n+ ! nature ( ! int]nal portions ( ! globe1 !re are nev]!less a numb] ( facts f :i* we may draw important inf]5ces ^u ! subject4 ,^! facts & ! inf]5ces bas$ ^u !m we %all n[ proce$ to consid]4 ,fir/ 9 importance among ^! we may m5tion ! results :i* h be5 obta9$ by weigh+ our globe4 ,v>i\s me?ods h be5 devis$ = accompli%+ ?is important object1 & ! conclusions arriv$ at by diff]5t me?ods agree s closely ) "o ano!r1 t !re is no room = d\bt z to ! sub/antial accuracy ( ^? results4 ,x may be tak5 z prov$ beyond ! possibility ( controv]sy t our globe is equal 9 weight to five & a half globes ( ! same size compos$ ( wat]1 or1 9 o!r words1 t ! av]age d5sity ( ! mat]ials compos+ ! globe is five & a half times z great z t ( wat]4 ,n[ ! d5sity ( ! mat]ials :i* compose ! cru/ ( ! globe is v mu* less ?an ?is1 v>y+ f ab\t two-&-"o-?ird to ?ree times t ( wat]4 ,h5ce we are compell$ to conclude t ! int]ior portions ( ! globe are ( f> great] d5sity ?an ! ext]ior portions2 t1 z a matt] ( fact1 ! mass ( ! globe is compos$ ( mat]ials hav+ twice ! d5sity ( ! rocks expos$ at ! surface4 ,sid5ote3 ,,d5sity ,,( ,,e>?',s ,,int]ior4 ,x has be5 sometimes argu$ t z all mat]ials "u int5se pressure appe> to yield to an appreciable ext5t1 & to all[ _! p>ticles to be pack$ into a small] compass1 we may f9d 9 ?is fact an explanation ( ! great d5sity ( ! int]nal p>ts ( ! globe4 ,x has 9 fact be5 sugge/$ t "u ! enorm\s pressure :i* mu/ be ex]t$ by masses ( rock sev]al ?\s& feet 9 ?ickness1 ! mat]ials ( :i* our e>? is compos$ may be compell$ to pack !mselves into less ?an "o-half ! compass :i* !y occupy at ! surface4 ,b ! ascription ( su* almo/ unlimit$ compressibility to solid sub/ances c be support$ nei!r by exp]im5t nor analogy4 ,v>i\s consid]ations po9t to ! probability t solid bodies yield to pressure up to a c]ta9 limit & no f>!r1 & t :5 ?is limit is rea*$ an increase 9 pressure is no long] att5d$ ) a r$uction 9 bulk4 ,if !n we are compell$ to reject ! idea ( ! unlimit$ compressibility ( solid sub/ances1 we mu/ conclude t ! int]ior portions ( our globe are compos$ ( mat]ials ( a diff]5t k9d f ^? :i* occur 9 its cru/4 ,& ?is conclusion1 z we %all pres5tly see1 is borne out by a numb] ( indep5d5t facts4 ,! /udy ( ! mat]ials eject$ f volcanic v5ts proves t ev5 at v mod]ate dep?s !re exi/ sub/ances diff]+ greatly 9 d5sity1 z well z 9 *emical composition4 ,! lighte/ lavas h a specific gravity ( #bc1 ! heavie/ ( ov] #c4 ,& t mat]ials ( ev5 great] d5sity are sometimes br\ght by volcanic action f ! e>?'s int]ior1 we h n[ ! cle>e/ pro(s4 ,sid5ote3 ,,relation ,,betwe5 ,,e>? ,,& ,,o!r ,,planets4 ,b 9 consid]+ a "q ( ?is k9d1 x w be well to rememb] t analogy may furni% u ) h9ts ^u ! subject :i* may prove to be by no means unimportant4 ,!re is no "q ^u :i* mod]n sci5ce has wr\ght out a m complete revolution 9 our ideas1 ?an t ( ! relation ( our e>? to ! o!r bodies ( ! univ]se4 ,we "k1 z ! result ( rec5t rese>*1 t our globe is "o ( a great family ( bodies1 mov+ ?r\gh space 9 simil> pa?s & 9 ob$i5ce to ! same laws4 ,a hundr$ ye>s ago ! prim>y & second>y planets ( ! sol> sy/em c\ld be almo/ numb]$ ^u ! f+]s2 n[ we recognise ! fact t !y exi/ 9 c\ntless millions1 pres5t+ e v>iety ( bulk f masses #a1djj times z l>ge z our e>? d[n to ! m]e/ planet>y du/4 ,betwe5 ! orbits ( ,m>s & ,jupit]1 m ?an #bjj small planets h be5 recognis$ z occurr+1 & e ye> additions are made to ! numb] ( ^! a/]oids4 ,comets h n[ be5 id5tifi$ ) /reams ( su* planet>y bodies1 ( m9ute size1 mov+ 9 regul> orbits ?r\gh our sy/em4 ,! magnific5t %[]s ( '%oot+-/>s' h be5 prov$ to be caus$ by ! passage ( ! e>? ?r\gh su* b&s ( travell+ bodies1 & '! zodiacal light' f9ds its mo/ probable explanation 9 ! supposition t ! sun is surr\nd$ by a great mass ( su* m9ute planets4 ,e increase 9 ! p[] ( ! telescope reveals to u ! exi/5ce ( new second>y planets or moons1 revolv+ ab\t ! prim>ies2 & ! wond]ful sy/em ( ! ,saturnian r+s is n[ expla9$ by ! prov$ exi/5ce ( great /reams ( su* second>y planets circl+ ar\nd x4 ,! sol> sy/em 0 =m]ly conceiv$ ( z a va/ solitude ?r\gh :i* a few gigantic bodies mov$ at awful di/ances f "o ano!r4 ,n[ we "k t ! suppos$ empty void is trav]s$ by c\ntless myriads ( bodies ( ! mo/ v>i$ dim5sions1 all mov+ 9 c]ta9 def9ite pa?s1 9 ob$i5ce to ! same laws1 ev] act+ & react+ ^u ea* o!r1 & occasionally com+ into collision4 ,!re are n want+ fur!r facts to prove t ! o!r planets are l our own 9 _m ( _! ph5om5a & surr\nd+s4 ,9 "s ( !m atmosph]ic ph5om5a h be5 detect$1 su* z ! =mation ( cl\ds & ! deposition ( sn[1 s t ! ext]nal =ces at "w on our globe act ^u !m also4 ,& t int]nal =ces1 l ^? we h be5 consid]+ 9 ! case ( our e>?1 are at "w 9 our neighb\rs1 is prov$ by ! great sol> /orms & ! condition ( ! moon's surface4 ,b ! results ( spectrum-analysis 9 rec5t ye>s h furni%$ new facts 9 pro( ( ! close relation%ip ( our e>? to ! num]\s simil> bodies by :i* x is surr\nd$4 ,s f> z obs]vation has yet gone we h reason = believ+ t n only ! memb]s ( ! sol> sy/em1 b ! m di/ant bodies ( ! univ]se1 are all compos$ ( ! same elem5t>y sub/ances z ^? :i* ent] into ! composition ( our globe4 ,! mo/ satisfactory in=mation conc]n+ ! composition & nature ( o!r planet>y bodies is d]iv$ f ! /udy ( ^? small planets :i* occasionally come into collision ) our globe1 & :i* h _! own prop] motion 9 space !reby arre/$4 ,^! meteorites1 z su* fall+ planet>y bodies are call$1 h ju/ly attract$ great att5tion1 & _! fragm5ts are treasur$ z ! mo/ valuable objects 9 our museums4 ,sid5ote3 ,,composition ,,( ,,meteorites4 ,! fir/ fact conc]n+ ^! meteorites1 :i* x is necess>y to notice1 is t !y are compos$ ( ! same *emical elem5ts z occur 9 ! e>?'s cru/4 ,no elem5t has yet be5 f\nd 9 any meteorite :i* 0 n previ\sly kn[n z exi/+ 9 ! e>?1 & ( ! sixty-five or sev5ty kn[n t]re/rial elem5ts no less ?an tw5ty-two h already be5 detect$ 9 meteorites4 ,!re are1 h[ev]1 a doz5 elem5ts :i* occur 9 ov]:elm+ proportions 9 ! e>?'s cru/4 ,we %all probably n be go+ too f> 9 say+ t ^! twelve elem5ts--namely1 oxyg51 silicon1 alum9ium1 calcium1 magnesium1 sodium1 potassium1 iron1 c>bon1 hydrog51 sulphur1 & *lor9e--make up among/ !m n less ?an #iii out ( #a1jjj p>ts ( ! e>?'s cru/1 & t all ! o!r fifty or sixty elem5ts are #hj comp>atively r>e t !y d n con/itute :5 tak5 altoge!r m ?an "o "p 9 #a1jjj ( ! rocks ( ! globe4 ,n[ all ( ^! twelve common t]re/rial elem5ts occur 9 meteorites1 & ! fact t ! r>] t]re/rial elem5ts h n z yet be5 f\nd 9 !m w n surprise anyone1 :o rememb]s h[ small is ! bulk ( all ! specim5s ( ^! meteorites exi/+ 9 our museums4 ,we h hi!rto insi/$ on ! po9ts ( resemblance 9 ! *emical composition ( meteorites & t ( ! rocks ( ! globe1 b we %all n[ h to indicate "s v important po9ts 9 :i* !y diff]4 ,:ile 9 ! rocks compos+ ! e>?'s cru/ oxyg5 =ms "o-half ( _! mass1 & silicon ano!r qu>t]1 we f9d t 9 ! meteorites ^! elem5ts1 ?\gh pres5t1 play a mu* less important "p4 ,! mo/ abundant elem5t 9 ! meteorites is iron2 & nickel1 *romium1 cobalt1 manganese1 sulphur1 & phosphorus1 are mu* m abundant 9 ^! extra-t]re/rial bodies ?an !y are 9 ! e>?'s cru/4 ,we h already ref]r$ to ! rem>kable fact t 9 our e>?'s cru/ ne>ly all ! o!r elem5t>y sub/ances are f\nd comb9$ 9 ! fir/ in/ance ) oxyg51 & t mo/ rocks consi/ ( ! oxide ( silicon comb9$ ) ! oxides ( v>i\s metals4 ,b ?is is by no means ! case ) ! meteorites4 ,9 !m we f9d metals l iron1 nickel1 cobalt1 c41 9 _! uncomb9$ condition1 & =m+ alloys ) "o ano!r4 ,! same & o!r metals also occur 9 comb9ation ) c>bon1 phosphorus1 *lor9e1 & sulphur1 & "s ( ! sub/ances ?us =m$ are q unkn[n among t]re/rial rocks4 ,comp\nds ( ! oxide ( silicon ) ! oxides ( ! metals su* z =m ! mass ( ! cru/ ( ! globe d occur 9 meteorites1 b !y play a mu* less important "p ?an 9 ! case ( ! t]re/rial rocks4 ,among ! sub/ances f\nd 9 meteorites are sev]al :i* d n exi/ among ! t]re/rial rocks--"s1 inde$1 :i* x seems impossible to conceive ( z be+ =m$ & pres]v$ "u t]re/rial conditions4 ,among ^! we may m5tion ! phosphide ( iron & nickel 7,s*reib]site71 ! sulphide ( *romium & iron 7,daubrelite71 ! protosulphide ( iron 7,troilite71 ! sulphide ( calcium 7,oldhamite71 ! proto*loride ( iron 7,lawr5cite71 & a peculi> =m ( cry/allis$ silica1 call$ by ,pr(essor ,maskelyne ',asmanite4' ,sid5ote3 ,,diff]5t ,,k9ds ,,( ,,meteorites4 ,!re are o!r ph5om5a exhibit$ by meteorites :i* indicate t !y mu/ h be5 =m$ "u conditions v diff]5t to ^? :i* prevail ^u ! e>?'s surface4 ,?us we f9d t fus$ iron & molt5 slag-l mat]ials h rema9$ entangl$ ) ea* o!r1 & h n sep>at$ z !y w\ld d if a great body l ! e>? 7 ne> to ex]cise ! v>y+ =ce ( gravity ^u ! two classes ( sub/ances4 ,aga91 meteorites are f\nd to h absorb$ _m times _! bulk ( hydrog5 gas1 & to exhibit peculi>ities 9 _! microscopic /ructure :i* c probably be only acc\nt$ = :5 we rememb] t !y 7 =m$ 9 ! int]planet>y spaces1 f> away f any great attract+ body4 ,b 9 rec5t ye>s a numb] ( v important facts h be5 discov]$ :i* may well lead u to devote a clos] att5tion to ! composition & /ructure ( meteorites4 ,x has be5 %[n1 on ! "o h&1 t "s meteorites conta9 sub/ances precisely simil> to ^? :i* are sometimes br\ght f ! e>?'s int]ior dur+ volcanic outbur/s2 &1 on ! o!r h&1 !re h be5 detect$1 among "s ( ! ejections ( volcanoes1 bodies :i* s closely resemble meteorites t !y 7 long mi/ak5 = !m4 ,bo? k9ds ( obs]vation seem to po9t to ! conclusion t ! e>?'s int]ior is compos$ ( simil> mat]ials to ^? :i* we f9d 9 ! small planets call$ meteorites4 ,m4 ,daubre has propos$ a v conv5i5t classification = meteorites1 divid+ !m into ! foll[+ f\r gr\ps3-- ,i4 ,holosid]ites2 consi/+ almo/ entirely ( metallic iron1 or ( iron alloy$ ) nickel1 /ony matt] be+ abs5t2 b sulphides1 phosphides1 & c>bides ( sev]al metals are (t5 diffus$ ?r\gh ! mass4 ,! poli%$ surfaces ( ^! meteoric irons1 :5 et*$ ) acid1 (t5 exhibit a rem>kable cry/all9e /ructure4 ,,ii4 ,syssid]ites2 9 :i* a network ( metallic iron encloses a numb] ( granul> masses ( /ony mat]ials4 ,,iii4 ,sporadosid]ites2 :i* consi/ ( a mass ( /ony mat]ials1 ?r\gh :i* p>ticles ( metallic iron are dissem9at$4 ,,iv4 ,asid]ites2 conta9+ no metallic iron1 b consi/+ entirely ( /ony mat]ials4 ,!re are1 besides ! meteorites belong+ to ^! pr9cipal gr\ps1 a few ( peculi> & exceptional composition1 :i* we ne$ n notice fur!r = our pres5t purpose4 ,f ! above classification x w be se5 t mo/ meteorites consi/ ( a mixture 9 v>y+ proportions ( metallic & /ony mat]ials4 ,sometimes ! metallic con/itu5ts are pres5t 9 great] proportions ?an ! /ony1 at o!r times ! /ony mat]ials pr$om9ate1 :ile occasionally "o or o!r ( ^! elem5ts may be :olly want+4 ,! /ony portions ( meteorites1 ^u c>eful exam9ation1 prove to be built up ( c]ta9 m9]als1 agree+ 9 _! *emical composition & _! cry/all9e =ms ) ^? :i* occur 9 ! rocks ( ! e>?'s cru/4 ,among ! ord9>y t]re/rial m9]als occurr+ 9 ! /ony portions ( meteorites1 we may especially m5tion oliv9e1 en/atite1 augite1 anor?ite1 *romite1 magnetite1 & pyrrhotite4 ,sid5ote3 ,,meteorites ,,& ,,ultra-,,basic ,,rocks4 ,! m9]als :i* occur 9 meteorites are 9 e case su* z are f\nd 9 ! m basic volcanic rocks--qu>tz1 & ! acid felsp>s1 ) ! o!r m9]als :i* occur 9 acid rocks1 be+ entirely abs5t 9 ! 'extra-t]re/rial' rocks4 ,n[1 besides ! ?ree great classes ( lavas :i* we h describ$ z be+ eject$ f volcanic v5ts1 !re are "s r>] mat]ials occasionally br\ght f ! e>?'s int]ior by ! same ag5cy1 t pres5t a mo/ wond]ful resemblance to ! /ony portions ( meteorites4 ,^! mat]ials we may call 'ultra-basic rocks4' ,_! specific gravity is v high1 usually exce$+ #c1 & !y conta9 a v l[ p]c5tage ( silica2 on ! o!r h&1 ! proportion ( iron & magnesia is (t5 mu* great] ?an 9 ord9>y t]re/rial rocks4 ,b ! mo/ rem>kable fact ab\t ^! ultra-basic rocks is1 t !y are almo/ entirely compos$ ( ! m9]als :i* occur 9 meteorites2 namely1 oliv9e1 en/atite1 augite1 anor?ite1 magnetite1 & *romite4 ,! ultra-basic rocks (t5 occur "u v peculi> conditions4 ,sometimes !y are f\nd =m+ ord9>y volcanic protrusions ?r\gh ! s$im5t>y rocks4 ,! rocks nam$ pikrites1 lh]zolites1 dunites1 c41 are examples ( su* igne\s protrusions compos$ ( ^! ultra-basic mat]ials1 & probably all ! true s]p5t9es are rocks ( ! same class :i* h absorb$ wat] & und]gone great alt]ation4 ,! ultra-basic rocks sometimes conta9 plat9um & o!r metals 9 ! free or uncomb9$ /ate4 ,b n unfrequ5tly we f9d among ! ord9>y ejections ( volcanoes1 nodules & fragm5ts ( su* ultra-basic mat]ials1 :i* h cle>ly be5 c>ri$ up ) ! o!r lavas f great dep?s 9 ! e>?'s cru/4 ,?us 9 ,auv]gne1 ! ,eifel1 ,bohemia1 ,/yria1 & _m o!r volcanic di/ricts1 ! basaltic lavas & tuffs are f\nd to conta9 nodules compos$ ( ! m9]als :i* are s highly *>act]i/ic ( meteorites4 ,su* nodules1 too1 (t5 =m ! c5tres ( ! volcanic bombs :i* are ?r[n out ( crat]s dur+ eruptions4 ,we ?us see t mat]ials id5tical 9 composition & "* ) ! /ony portions ( meteorites1 exi/ )9 ! e>?'s int]ior1 & are ?r[n out on its surface by volcanic action4 ,a /ill m int]e/+ discov]y has be5 made 9 rec5t ye>s2 namely1 t mat]ials simil> to ! metallic portion ( meteorites1 & consi/+ ( nickelif]\s iron1 also occur 9 deep-seat$ portions ( ! e>?'s cru/1 & are br\ght to ! surface dur+ p]iods ( igne\s activity4 ,9 ! ye> #ahgj1 ,pr(essor ,nord5skild made a mo/ important discov]y at ,ovifak1 on ! s\? side ( ! ,isl& ( ,disko1 (f ! ,gre5l& coa/4 ,on ! %ore ( ! isl& a numb] ( blocks ( iron 7 se51 & ! *emical exam9ation ( ^! prov$ t1 l ord9>y metallic meteorites1 !y consi/$ ( iron alloy$ ) nickel & cobalt4 ,sid5ote3 ,,iron-,,masses ,,( ,,ovifak4 ,n[1 :5 ! facts conc]n+ ! masses ( native iron ( ,ovifak 7 made kn[n1 ! fir/ & mo/ natural explanation :i* pres5t$ itself to e m9d 01 t ^! 7 a numb] ( meteorites :i* at "s pa/ p]iod _h fall5 ^u ! e>?'s surface4 ,metallic iron4 ,opaque cry/als ( magnetite 7black oxide ( iron74 ,transp>5t cry/als ( felsp>1 augite1 & oliv9e4 ,illu/ration3 ,fig4 #hg4--,section ( basalt f ,ovifak1 ,gre5l&1 ) p>ticles ( metallic iron diffus$ ?r\gh its mass4 ,b a fur!r exam9ation ( ! locality reveal$ a numb] ( facts :i*1 z ,pr(essor ,/e5/rup po9t$ out1 x is v difficult to reconcile ) ! !ory t ! ,ovifak masses ( iron are ( meteoric orig94 ,! di/rict ( ,we/]n ,gre5l&1 :]e ^! masses 7 discov]$1 has be5 ! sc5e ( volcanic outbur/s on ! gr&e/ scale dur+ ! ,mioc5e p]iod4 ,9 close proximity to ! great iron masses1 !re are se5 a numb] ( basaltic dykes2 &1 :5 ^! dykes are c>efully exam9$1 ! basaltic rock ( :i* !y are compos$ is se5 to be full ( p>ticles ( metallic iron4 ,9 fig4 #hg1 we h a draw+ made f a section ( ! ,ovifak basalts magnifi$ f\r or five diamet]s4 ,! rock-mass is se5 to be compos$ ( black1 opaque magnetite1 & transp>5t cry/als ( augite1 labradorite1 oliv9e1 c42 :ile1 ?r\gh ! :ole1 p>ticles ( metallic iron are f\nd entangl$ among ! diff]5t cry/als 9 ! mo/ rem>kable mann]4 ,x has be5 sugge/$ t ?is s+ul> rock might h be5 =m$ by a meteorite fall+1 9 ,mioc5e times1 into a lava-/ream 9 a /ate ( inc&esc5ce4 ,b ! relation ( ! metallic p>ticles to ! /ony mat]ials is su* z to l5d no support :atev] to ?is r /ra9$ hypo!sis4 ,a c>eful /udy ( all ! facts ( ! case by ,lawr5ce ,smi?1 ,daubre1 & o!rs well acqua9t$ ) ! ph5om5a exhibit$ by meteorites1 has l$ to ! conclusion t ! l>ge iron-masses ( ,ovifak1 z well z ! p>ticles ( metallic iron diffus$ ?r\gh ! surr\nd+ basalts1 are all ( t]re/rial orig91 & h be5 br\ght by volcanic action f ! e>?'s int]ior4 ,x is probable t1 j z we f9d 9 _m basaltic lavas nodules ( ultra-basic mat]ials simil> to ! /ony p>ts ( meteorites1 s 9 ^! basalts ( ,ovifak we h masses ( iron alloy$ ) nickel1 simil> to ! metallic portions ( meteorites4 ,bo? ! /ony & metallic enclosures 9 ! basalt are 9 all probability d]iv$ f deep] portions ( ! e>?'s cru/4 ,by ! wea!r+ away ( ! basalt ( ,ovifak1 ! l>g] masses ( metallic iron h be5 left expos$ ^u ! %ore :]e !y 7 f\nd4 ,!re are a numb] ( o!r facts :i* seem to support ?is />tl+ conclusion4 ,?us x has be5 %[n by ,pr(essor ,&rews t c]ta9 basalts 9 our own isl&s conta9 p>ticles ( metallic iron ( microscopic dim5sions1 & x is n improbable t "s ( ! masses ( nickelif]\s iron f\nd 9 v>i\s p>ts ( ! e>?'s surface1 :i* h hi!rto be5 reg>d$ z meteorites1 are1 l ^? ( ,ovifak1 ( t]re/rial orig94 ,sid5ote3 ,,mat]ials ,,fill+ ,,metallic-,,ve9s4 ,ano!r piece ( evid5ce po9t+ 9 ! same direction1 is d]iv$ f ^? great fissures communicat+ ) ! int]ior ( our globe :i* become fill$ ) metallic m9]als1 & are kn[n to u z m9]al-ve9s4 ,9 ^! m9]al-ve9s ! native metals1 _! alloys1 & comb9ations ( ^! ) sulphur1 *lor9e1 phosphorus1 c41 are frequ5tly pres5t4 ,b oxides ( ! metals1 except z products ( subsequ5t alt]ation1 occur f> less frequ5tly ?an 9 ! e>?'s cru/ g5]ally4 ,h5ce we are l$ to conclude t ! sub/ances :i* 9 ! out] "p ( ! e>?'s cru/ always exi/ 9 comb9ation ) oxyg51 are at great] dep?s 9 a free & uncomb9$ condition4 ,nor is x a circum/ance altoge!r unwor?y ( att5tion t ! rese>*es ( ,mr4 ,norman ,locky] & o!r a/ronom]s1 bas$ on ! kn[n facts ( ! relative d5sities ( ! sev]al memb]s ( ! sol> sy/em1 & ! asc]ta9$ relations ( ! diff]5t sol> envelopes1 h l$ to conclusions closely 9 accord ) ^? arriv$ at by geologi/s4 ,^! rese>*es appe> to w>rant ! hypo!sis t ! int]ior ( our globe consi/s ( metallic sub/ances uncomb9$ ) oxyg51 & t among ^! metallic sub/ances iron plays an important "p4 ,our globe1 z we "k1 is a great magnet1 & ! rem>kable ph5om5a ( t]re/rial magnetism may also n improbably f9d _! explanation 9 ! fact t metallic iron =ms #hj l>ge a portion ( ! e>?'s int]ior4 ,! int]e/+ facts :i* we h be5 consid]+ may be made cle>] by ! accompany+ diagram 7fig4 #hh74 ,! mat]ials eject$ f volcanic v5ts 7lavas7 are 9 almo/ all cases comp\nds ( silicon & ! v>i\s metals ) oxyg54 ,9 ! light] or acid lavas oxyg5 con/itutes "o-half ( _! weight1 & ! proportion ( metals ( ! iron-gr\p is v small4 ,z we pass to ! heavi] int]m$iate & basic lavas1 we f9d ! proportion ( oxyg5 dim9i%+1 & ! metals ( ! alkal9e e>?s 7magnesium & calcium7 ) ! metals ( ! iron-gr\p increas+1 9 quantity4 ,9 ! small & int]e/+ gr\p ( ! ultra-basic lavas ! proportion ( oxyg5 is comp>atively small1 & ! proportion ( magnesium & iron v high4 ,s mu* = ! t]re/rial rocks4 ,illu/ration3 ,fig4 #hh4--;,diagram illu/rat+ ! relation betwe5 ! ,t]re/rial & ! ,extra-,t]re/rial ,rock4 ,sid5ote3 ,,t]re/rial ,,& ,,extra-,,t]re/rial ,,rocks4 ,n[ let u turn our att5tion to ! extra-t]re/rial rocks or ^? f\nd 9 meteorites4 ,! ,asid]ites are q id5tical 9 composition ) ! ultra-basic lavas ( our globe1 b 9 ! ,sporadosid]ites & ! ,syssid]ites we f9d ! proportion ( oxyg5 rapidly dim9i%+1 & t ( metallic iron increas+4 ,f9ally1 9 ! ,holosid]ites ! oxyg5 entirely disappe>s1 & ! :ole mass becomes metallic4 ,f ! ,holosid]ites at "o end ( ! *a9 to ! add lavas at ! o!r1 we f9d !re is a complete & cont9u\s s]ies2 ! rocks ( t]re/rial orig9 ov]lapp+1 9 _! lea/ oxydiz$ repres5tatives1 ! mo/ highly oxydiz$ repres5tatives ( ! extra-t]re/rial rocks4 ,b ! discov]y at ,ovifak ( ! iron-masses1 & ! basalts ) iron dissem9at$1 has af=d$ ano!r v important l9k1 plac+ ! t]re/rial & extra-t]re/rial rocks 9 clos] relations ) "o ano!r4 ,all ^! facts appe> to po9t to ! conclusion t ! e>?'s int]ior consi/s ( metallic sub/ances ei!r q uncomb9$ or simply alloy$ ) "o ano!r1 & among ^! iron is v conspicu\s by its abundance4 ,! out] cru/1 :i* is probably ( no great ?ickness1 conta9s an enorm\s proportion ( oxyg5 & silicon comb9$ ) ! mat]ials :i* con/itute ! int]ior portions ( our globe4 ,x may be1 z has be5 sugge/$ by a/ronom]s1 t our e>? consi/$ at "o "t ( a solid metallic mass surr\nd$ by a vapor\s envelope ( metalloids1 & t ! :ole ( ! latt]1 ) ! exception ( ! con/itu5ts ( ! atmosph]e & ocean1 h gradually ent]$ into comb9ation ) ! metals ( ! nucleus to =m ! exi/+ cru/ ( ! globe4 ,b ( ?is p]iod ! geologi/ c take no cognisance4 ,! records :i* he /udies evid5tly comm5c$ at a long subsequ5t p]iod1 :5 ! conditions prevail+ at ! e>?'s surface diff]$ b little1 if at all1 f ^? :i* exi/ at ! pres5t day4 ,equally little has ! geologi/ to d ) speculations conc]n+ a f> di/ant future :51 z "s philosoph]s h sugge/$1 ! "w ( comb9ation ( ! wat]s & atmosph]e ( ! e>?'s surface ) ! metallic sub/ances ( its int]ior %all be complet$1 & our globe1 entirely depriv$ ( its fluid envelopes1 r$uc$ to ! condition 9 :i* we f9d our satellite1 ! moon4 99 99 99 99 99 ,sid5ote3 ,,physical ,,condition ,,( ,,e>?',s ,,int]ior4 ,!re is ano!r class ( enquiries conc]n+ ! e>?'s int]ior to :i* ! att5tion ( bo? geologi/s & a/ronom]s has long be5 direct$--t1 namely1 :i* deals ) ! problem ( ! physical condition ( ! int]ior ( our globe4 ,! fact t masses ( molt5 mat]ials are se5 at _m po9ts ( ! e>?'s surface to issue f figures 9 ! cru/ ( our globe1 seems at fir/ sight to f9d a simple explanation if we suppose our planet to consi/ ( a fluid c5tral mass surr\nd$ by a solid cru/4 ,h5ce we f9d t among ^? :o fir/ ?\ght ^u ?is subject1 ?is hypo!sis ( a liquid c5tre & a solid cru/ 0 almo/ univ]sally accept$4 ,?is hypo!sis 0 suppos$ to f9d fur!r support 9 ! fact t1 z we p5etrate into ! e>?'s cru/ by m9es or bor+ op]ations1 ! temp]ature is f\nd to cont9ually increase4 ,x 0 imag9$1 too1 t ?is condition ( our planet w\ld be/ agree ) ! requirem5ts ( ! nebul> hypo!sis ( ,laplace1 :i* expla9s ! =mations & movem5ts ( ! bodies ( ! sol> sy/em by ! cool+ d[n ( a nebul\s mass4 ,b a m c>eful & critical exam9ation ( ! "q has l$ _m geologi/s & a/ronom]s to reject ! hypo!sis t ! e>? consi/s ( a great fluid mass surr\nd$ by a comp>atively ?9 %ell ( solid mat]ials4 ,volcanic outbur/s & e>?quake tremors1 ?\gh s t]rible & de/ructive to man & 8 works1 are b slight & inconsid]able di/urbances 9 a globe ( su* va/ dim5sions z t on :i* we live4 ,! condition ( ! cru/ ( ! globe is1 9 spite ( volcanic & e>?quake manife/ations1 "o ( g5]al /ability2 & ?is g5]al /ability has c]ta9ly be5 ma9ta9$ dur+ ! va/ p]iods cov]$ by ! geological record4 ,su* a /ate ( ?+s seems q irreconcilable ) ! supposition t1 at no great dep? f ! surface1 ! :ole mass ( ! globe is 9 a liquid condition4 ,if1 on ! o!r h&1 x be suppos$ t ! solid cru/ ( ! globe is sev]al hundr$s ( miles 9 ?ickness1 x is difficult to und]/& h[ ! local c5tres ( volcanic activity c\ld be suppli$ f su* deep-seat$ s\rces4 ,!re are o!r facts :i* seem equally irreconcilable ) ! hypo!sis ( a fluid c5tre & a ?9 solid cru/ 9 our globe4 ,if all igne\s products 7 d]iv$ f "o c5tral res]voir1 we might fairly expect to f9d a mu* great] uni=mity ( "* among ^? products ?an really exi/s4 ,b 9 "s cases1 mat]ials ( totally diff]5t composition are eject$ at ! same "t f closely adjo9+ volcanic di/ricts4 ,?us 9 ,hung>y & ,bohemia1 z we h se51 lavas ( totally diff]5t "* 7 be+ extrud$ dur+ ! ,mioc5e p]iod4 ,9 ! isl& ( ,hawaii1 z ,pr(essor ,dana has po9t$ out1 igne\s ejections h tak5 place at a crat] #ad1jjj feet above ! sea-level1 :ile a closely adjo9+ op5 v5t at a level #aj1jjj feet l[] exhibit$ no k9d ( sympa?y ) ! di/urbance4 ,:atev] may be ! cause ( volcanic action1 x seems cle> t x does n orig9ate 9 a univ]sal mass ( liquefi$ mat]ial situat$ at no great dep? f ! e>?'s surface4 ,! conclusions arriv$ at by a/ronom]s & physici/s is "o q 9 accord ) ^? :i* geologi/s h rea*$ by totally diff]5t me?ods4 ,x is n[ v g5]ally admitt$ t if ! e>? 7 n a rigid mass1 its behavi\r "u ! attract live influ5ces ( ! surr\nd+ memb]s ( ! sol> sy/em w\ld be v diff]5t to :at is f\nd to be ! case4 ,sid5ote3 ,,argum5ts ,,aga9/ ,,liquid ,,int]ior4 ,t ! e>? is 9 a solid condition to a great dep? f ! surface1 & possibly q to ! c5tre1 is a conclusion conc]n+ :i* !re c be little d\bt2 & 9 ! next *apt] we %all endeav\r to %[ t su* a condition ( ?irds is by no means incompatible ) ^? manife/ations ( int]nal en]gy1 ! ph5om5a ( :i* we are consid]+ 9 ?is "w4 ,! "q1 !re=e1 ( ! complete solidity ( our globe1 or ( its consi/+ ( a solid & a liquid portion1 is "o ( speculative int]e/ only1 & is 9 no way involv$ 9 our inve/igations conc]n+ ! nature & orig9 ( volcanic activity4 ,we may conclude ?is *apt] by enum]at+ ! sev]al hypo!ses :i* h at diff]5t times be5 ma9ta9$ conc]n+ ! nature ( ! int]ior ( our globe4 ,fir/4 ,x has be5 sugge/$ t ! e>? consi/s ( a fluid or semi-fluid nucleus surr\nd$ & enclos$ 9 a solid %ell4 ,"s h ma9ta9$ ?is %ell to be ( su* insignificant ?ickness1 z comp>$ ) ! bulk ( ! int]ior liquid mass1 t portions ( ! latt] are able to rea* ! e>?'s surface ?r\gh movem5ts & fractures ( ! out] %ell1 & t 9 ?is mann] volcanic manife/ations orig9ate4 ,o!rs1 impress$ ) ! g5]al /ability & rigidity ( ! globe z a :ole1 h ma9ta9$ t ! out] solid %ell mu/ h a v consid]able ?ickness1 am\nt+ probably to n less ?an sev]al hundr$s ( miles4 ,b ?r\gh a %ell ( su* ?ickness x is difficult to conceive ( ! liquid masses ( ! int]ior f9d+ _! way to ! surface1 & ^? :o h held ?is view are driv5 to sugge/ "s o!r means by :i* local developm5ts ( volcanic action might be br\ght ab\t4 ,secondly4 ,"s physici/s h ass]t$ t a globe ( liquid matt] radiat+ its heat into space1 w\ld t5d to solidify bo? at ! surface & ! c5tre1 at ! same "t4 ,! consequ5ce ( ?is action w\ld be ! production ( a sph]e ) a solid ext]nal %ell & a solid c5tral nucleus1 b ) an int]pos$ lay] 9 a fluid or semi-fluid condition4 ,x has be5 po9t$ out t if we suppose ! solidification to h gone s f>1 z to h caus$ ! p>tial union ( ! int]ior nucleus & ! ext]nal %ell1 we may conceive a condition ( ?+s 9 :i* ! /ability & rigidity is suffici5t to satisfy bo? geologi/s & a/ronom]s1 b t 9 /ill unsolidifi$ pockets or res]voirs1 fill$ ) liquefi$ rock1 betwe5 ! nucleus & ! %ell1 we %\ld h a compet5t cause = ! production ( ! volcanic ph5om5a ( ! globe4 ,9 ?is hypo!sis1 h[ev]1 x is assum$ t ! cool+ at ! c5tre & ! surface ( ! globe w\ld g on at su* rates t ! res]voirs ( liquid mat]ial w\ld be left at a mod]ate dep? f ! surface1 s t easy communication c\ld be op5$ betwe5 !m & volcanic v5ts4 ,sid5ote3 ,,review ,,( ,,! ,,sev]al ,,hypo!ses4 ,?irdly4 ,x has be5 ma9ta9$ t ! e>? may h become p]fectly solid f ! c5tre to ! surface4 ,^? :o hold ?is view endeav\r to acc\nt = ! ph5om5a ( volcanoes 9 "o ( two ways4 ,x may be1 !y say1 t ! deep-seat$ rock-masses1 ?\gh actually solid1 are 9 a /ate ( pot5tial liquidity2 t ?\gh r$uc$ to a solid /ate by ! int5se pressure ( ! sup]9cumb5t masses1 yet su* is ! condition ( un/able equilibrium 9 ! :ole mass1 t ! comp>atively slight movem5ts & *anges tak+ place at ! e>?'s surface suffice to br+ ab\t ! liquefaction ( portions ( its cru/ & consequ5t manife/ations ( volcanic en]gy4 ,b ,x may be1 z o!r support]s ( ! doctr9e ( ! e>?'s complete solidity h ma9ta9$1 t ! ph5om5a ( volcanoes h no direct connection ) a suppos$ inc&esc5t condition ( our planet at all1 & t !re are *emical & me*anical =ces at "w )9 our globe :i* are q compet5t to produce at ! surface all ^? rem>kable ph5om5a :i* we id5tify ) volcanic action4 ,f ?is summ>y ( ! speculative views :i* h be5 ent]ta9$ ^u ! subject ( ! physical condition ( ! e>?'s int]ior1 x w be cle> t at pres5t we h n suffici5t evid5ce = arriv+ at any?+ l a def9ite solution ( ! problem4 ,! conditions ( temp]ature & pressure :i* exi/ 9 ! int]ior ( a globe ( su* va/ dim5sions z our e>?1 are s f> remov$ f ^? :i* we c imitate 9 our exp]im5tal enquiries1 & x is s unsafe to pu% ! application ( laws arriv$ at by ! latt] to ! extreme limits requir$ by ! =m]1 t we %all d well to pause be=e attempt+ to dogmatise on su* a difficult "q4 ,9 ! next *apt] we %all endeav\r to grapple ) a some:at m hopeful task1 to po9t out h[ f> obs]vation & exp]im5t h enabl$ u to (f] a reasonable explanation ( ! wond]ful s]ies ( ph5om5a :i* are display$ dur+ outbur/s ( volcanic activity4 ,,*apt] ,,xii4 ,,! ,,attempts ,,:i* ,,h ,,be5 ,,made ,,to ,,expla9 ,,! ,,causes ,,( ,,volcanic ,,action4 ,e complet$ sci5tific inve/igation mu/ consi/ ( f\r s]ies ( op]ations4 ,9 ! fir/ ( ^! an attempt is made to collect ! :ole ( ! facts be>+ on ! "q1 by means ( obs]vation & exp]im5t2 ! latt] be+ only obs]vation "u conditions det]m9$ by ourselves4 ,9 ! second /age ( ! enquiry1 ! att5tion is direct$ to classify+ & gr\p+ ! isolat$ facts1 s z to det]m9e _! be>+s ^u "o ano!r1 & ! g5]al conclusions to :i* !y appe> to po9t4 ,9 ! ?ird /age1 x is s\ght to frame an hypo!sis :i* %all embrace all ! obs]v$ facts1 & %all be 9 h>mony ) ! g5]al conclusions d]iv$ f !m4 ,9 ! f\r? /age1 ?is hypo!sis is put to ! mo/ rigid te/2 comp>+ ! results :i* mu/ foll[1 if x be true1 ) ! ph5om5a actually obs]v$1 & reject+ or am5d+ our hypo!sis accord+ly4 ,e great sci5tific !ory has ?us be5 e/abli%$ by ^! f\r processes--obs]vation1 g5]alisation1 hypo!sis1 & v]ification4 ,! enquiry conc]n+ ! nature & causes ( volcanic action is f> f be+ a complet$ "o4 ,x is true t _m hypo!ses ^u ! subject h be5 fram$1 b 9 too _m in/ances ^! h n be5 bas$ on accurate obs]vations & c>eful g5]alisations1 & c be reg>d$ z little bett] ?an m]e guesses4 ,inde$1 ! /ate ( ! enquiry at ! pres5t "t w\ld seem to be z foll[s4 ,al?\gh mu* rema9s to be done 9 ! direction bo? ( obs]vation & exp]im5t1 ! ma9 facts ( ! case h be5 e/abli%$ ^u irrefragable evid5ce4 ,! classification & comp>ison ( ^! facts h l$ to ! recognition ( c]ta9 laws1 :i* seem to embrace all ! kn[n facts4 ,to acc\nt = ^! facts & _! demon/rat$ relations to "o ano!r1 c]ta9 t5tative hypo!ses h be5 sugge/$2 b 9 no case c x be truly said t ^! latt] h s f> /ood ! te/ ( exact enquiry z to des]ve to rank z demon/rat$ tru?s4 ,a complete & consi/5t !ory ( volcanic action /ill rema9s to be discov]$4 ,sid5ote3 ,,value ,,& ,,limits ,,( ,,hypo!ses4 ,9 accordance ) ! plan :i* we h sket*$ out = ourselves at ! comm5cem5t ( ?is "w1 we %all aim at foll[+ :at has be5 ! ord] ( inve/igation & discov]y 9 our /udy ( volcanic action2 & 9 ?is conclud+ *apt] we %all indicate ! diff]5t hypo!ses by :i* x has be5 propos$ to acc\nt = ! v>i$ ph5om5a1 :i* we h discuss$ 9 ! prec$+ pages1 & _! rem>kable relations to "o ano!r4 ,we %all endeav\r1 9 pass+1 to indicate h[ f> ^! sev]al hypo!ses appe> to be probable1 z satisfy+ a l>g] or small] numb] ( ^? conditions ( ! problem :i* h be5 e/abli%$ by obs]vation1 exp]im5t1 & c>eful reason+2 b we %all at ! same "t c>efully avoid su* advocacy ( any p>ticul> views z w\ld t5d to a prejudgm5t ( ! "q4 ,hypo!sis is1 z we h se51 "o ( ! legitimate & necess>y op]ations 9 sci5tific inve/igation4 ,x only becomes a dang]\s & trea*]\s weapon :5 x is made to prec$e r ?an to foll[ obs]vation & exp]im5t1 or :5 be+ reg>d$ ) pat]nal indulg5ce1 an attempt is made to %ield x f ! rel5tless logic ( facts4 ,good & bad hypo!ses mu/ be all[$ to 'gr[ toge!r till ! h>ve/2' su* z are unable to accommodate !mselves to ! surr\nd+ conditions impos$ by newly-discov]$ facts & fre%ly-e/abli%$ laws w assur$ly p]i%2 & 9 ?is '/ruggle = exi/5ce' ! true hypo!sis w 9 ! end survive1 :ile ! false ones p]i%4 ,x may well happ51 h[ev]1 t among ! hypo!ses :i* h up to ! pres5t "t be5 fram$1 none w be f\nd to entirely satisfy all ! conditions ( ! problem4 ,new discov]ies 9 physics & *emi/ry h sugge/$ fre% explanations ( volcanic ph5om5a 9 ! pa/1 & may cont9ue to d s 9 ! future2 & ! true !ory ( volcanic action1 :5 x is at la/ discov]$1 may comb9e _m ( ! pr9ciples :i* n[ seem to be peculi> to diff]5t hypo!ses4 ,let u1 9 ! fir/ place1 enquire :at are ! facts :i* mu/ be acc\nt$ = 9 any !ory ( volcanic action4 ,we h already be5 l$ to ! conclusion t ! ph5om5a exhibit$ by volcanoes 7 entirely produc$ by ! escape ( imprison$ wat] & o!r gases f masses ( inc&esc5t & fluid rock4 ,our subsequ5t exam9ation ( ! problem confirm$ ! conclusion t 9 all cases ( volcanic outbur/ we h molt5 rock-mat]ials f :i* wat] & o!r gases issue ) great] or less viol5ce4 ,! two great facts to be acc\nt$ =1 !n1 9 any attempt$ explanation ( volcanic ph5om5a1 are ! exi/5ce ( ?is high temp]ature at c]ta9 po9ts )9 ! e>?'s cru/1 & ! pres5ce ( great quantities ( wat] & gas1 imprison$ 9 ! rocks4 ,we %all p]haps simplify ! enquiry if we exam9e ^! two que/ions sep>ately1 &1 9 ! fir/ place1 review ^? hypo!ses :i* h be5 sugge/$ to acc\nt = high temp]atures 9 ! subt]ranean regions1 &1 9 ! second place1 exam9e ^? :i* seek to expla9 ! pres5ce ( l>ge quantities ( imprison$ wat] & gases4 ,sid5ote3 ,,increase ,,( ,,temp]ature ,,) ,,dep?4 ,t a high temp]ature exi/s 9 ! e>?'s cru/ at "s dep? f ! surface is a act :i* does n admit ( any d\bt4 ,e %aft sunk = m9+ op]ations1 & e deep bor+ made = ! purpose ( obta9+ wat]1 proves t a m or less regul> increase ( temp]ature takes place z we p5etrate d[nw>ds4 ,! av]age rate ( ?is increase ( temp]ature has be5 e/imat$ to be ab\t #a ,fahr5heit = e #ej or #fj feet ( dep?4 ,n[ if x be assum$ t ?is regul> increase ( temp]ature cont9ues to great dep?s1 a simple calculation proves t at a dep? ( #i1jjj feet a temp]ature ( #bab ,fahr5heit w be f\nd--"o suffici5t to boil wat] at ! e>?'s surface--:ile at a dep? ( #bh miles ! temp]ature w be high en\gh to melt ca/-iron1 & at #cd miles to fuse plat9um4 ,s m>k$ is ?is /eady increase ( temp]ature z we g d[nw>ds1 t x has be5 s]i\sly propos$ to make v deep bor+s 9 ord] to obta9 supplies ( w>m wat] = heat+ our t[ns4 ,arago & ,walf]d9 sugge/$ ?is me?od = w>m+ ! ,j>d9 des ,plantes at ,p>is2 & n[ t su* important improvem5ts h be5 devis$ 9 c>ry+ bor+s to enorm\s dep?s1 ! "t may n be f> di/ant :5 we %all draw ext5sively ^u ^! supplies ( subt]ranean heat4 ,at ! pres5t "t ! city ( ,buda-,pe/h is ext5sively suppli$ ) hot-wat] f an und]gr\nd s\rce4 ,%\ld our coal-supply ev] fail x may be well to rememb] t we h ^! inexhau/ible supplies ( heat ev]y:]e b5ea? our feet4 ,b al?\gh we may conclude t at ! mod]ate dep?s we h indicat$ su* high temp]atures exi/1 x w\ld n be safe to inf]1 z "s h done1 t at a di/ance ( only #dj or #ej miles f ! surface ! mat]ials compos+ our globe are 9 a /ate ( actual fusion4 ,bo? !ory & exp]im5t indicate t "u increas$ pressure ! fus+ po9t ( solid bodies is rais$2 & j z 9 a ,pap9's dige/] we may h wat] reta9$ by high pressure 9 a liquid condition at a temp]ature f> above #bab ,f41 s 9 ! int]ior ( ! e>?1 masses ( rock may exi/ 9 a solid /ate1 at a temp]ature f> above t at :i* !y w\ld fuse at ! e>?'s surface4 ,we may speak ( su* rock-masses1 reta9$ 9 a solid condition by int5se pressure1 at a temp]ature f> above _! fus+ po9t at ! e>?'s surface1 z be+ 9 a 'pot5tially liquid condition4' ,^u any relief ( pressure su* masses w\ld at once assume ! liquid /ate1 j z ! sup]heat$ wat] 9 a ,pap9's dige/] imm$iately fla%es into /eam ^u ! fracture ( ! /rong vessel by :i* x is conf9$4 ,we h already se5 h[ ! action at volcanic v5ts (t5 appe>s to indicate j su* a manife/ation ( ela/ic =ces1 z w\ld be exhibit$ by ! relief ( sup]heat$ masses f a /ate ( conf9em5t by pressure4 ,9 reason+ ^u que/ions ( ?is k9d1 h[ev]1 we mu/ always be ^u our gu>d aga9/ giv+ undue ext5sion to pr9ciples & laws :i* seem to be cle>ly e/abli%$ by exp]im5t at ! e>?'s surface4 ,x is well to rememb] h[ exce$+ly limit$ is our comm& ( extreme pressures & high temp]atures1 :5 comp>$ ) ^? :i* may exi/ )9 a body ( ! dim5sions ( our globe4 ,sid5ote3 ,,effect ,,( ,,pressure ,,on ,,fusion-,,po9t4 ,if we 7 to imag9e a set ( intellig5t creatures1 :o 7 able to comm& only a range ( temp]atures f #ej to #bjj ,f41 engag$ ^u an inve/igation ( ! prop]ties ( wat]1 we %all easily und]/& h[ unsafe x may be to ext5d g5]alisations f> beyond ! limits cov]$ by actual exp]im5t4 ,su* be+s1 f _! obs]vation ( ! regul> *anges ( volume ( wat] at all ! temp]atures !y c\ld comm&1 might inf] t at /ill high] & l[] temp]atures ! same rates ( expansion & contraction w\ld be ma9ta9$4 ,yet1 z we well "k1 su* an inf]5ce w\ld be q wide ( ! tru?2 = a little above #bjj ,f4 wat] sudd5ly exp&s to #a1gjj times its volume1 & n f> bel[ #ej ,f4 ! contraction is sudd5ly *ang$ = expansion4 ,x has be5 argu$ by ! late ,mr4 ,david ,=bes & o!rs t1 inasmu* z exp]im5t has %[n t--?\gh ! fus+ po9ts ( solids are rais$ by pressure1 yet t ?is rise ( ! fus+ po9ts goes on 9 a dim9i%+ ratio z comp>$ ) ! pressures appli$--a limit w probably be rea*$ at :i* ! mo/ int5se pressure w n be suffici5t to reta9 sub/ances at a high temp]ature 9 _! solid /ate4 ,! fact t gases _c be reta9$ 9 a liquid condition by ! mo/ int5se pressure at a temp]ature above _! critical po9t1 may seem by analogy to fav\r ! same conclusion4 ,h5ce1 ,david ,=bes1 ,dana1 & o!r au?ors1 h argu$ 9 fav\r ( ! exi/5ce ( a great liquid nucleus 9 our globe cov]$ by a comp>atively ?91 solid cru/4 ,& if we accept ! suppos$ pro(s ( a con/ant increase ( temp]ature f ! surface to ! c5tre ( ! globe1 su* a conclusion appe>s to be at lea/ z well f\nd$ z t :i* reg>ds ! c5tral masses ( ! e>? z ma9ta9$ 9 a solid condition by int5se pressure4 ,a little consid]ation w1 h[ev]1 conv9ce u t ! facts :i* h be5 reli$ ^u z prov+ ! int5sely heat$ condition ( ! c5tral masses ( our globe1 are by no means s conclusive z has be5 suppos$4 ,! e>?'s =m1 :i* ma!maticians h %[n to be exactly t :i* w\ld be acquir$ by a globe compos$ ( yield+ mat]ials rotat+ on its axis at ! rate :i* our planet does1 has (t5 be5 adduc$ z prov+ t ! latt] 0 n always 9 a rigid & unyield+ condition4 ,9 ! same way1 all ! rem>kable facts & relations ( ! bodies ( ! sol> sy/em1 :i* h be5 %[n by a/ronom]s to l5d su* support to ! nebul> hypo!sis1 h be5 ?\ght1 at ! same "t1 to fav\r ! view t our e>? is /ill 9 a condition ( uncomplet$ solidification4 ,b x is q admissible to accept ! nebul> hypo!sis & ! view t our globe atta9$ its pres5t =m :ile /ill 9 a /ate ( fluidity1 & at ! same "t to ma9ta9 t our e>? has long s9ce rea*$ its condition ( complete solidification4 ,& !re are n a few facts :i* appe> to l5d support to su* a conclusion4 ,sid5ote3 ,,suppos$ ,,pro(s ,,( ,,liquid ,,nucleus4 ,if ! rapid rate ( increase 9 temp]ature :i* has be5 demon/rat$ to occur at s _m p>ts ( ! e>?'s surface be ma9ta9$ to ! c5tre1 !n1 z argu$ by ,david ,=bes & ,dana1 x is difficult to conceive ( our e>? z be+ 9 any o!r condition ?an t ( a liquid mass cov]$ by a comp>atively ?9 cru/4 ,! objection to ?is view1 bo? ^u geological & a/ronomical gr\nds1 we h po9t$ out 9 ! previ\s *apt]4 ,be=e accept+ z a demon/rat$ conclusion ?is notion ( a con/ant increase ( temp]ature f ! surface to ! c5tre ( our globe1 x may be well to re-exam9e ! facts :i* are reli$ ^u z prov+ x4 ,t !re is a g5]al increase ( temp]ature s f> z we are able to g d[nw>ds 9 ! e>?'s cru/1 !re c1 z we h se51 be no d\bt :atev]4 ,yet x may be well to be> 9 m9d h[ v limit$ is ! range ( our obs]vation on ! subject4 ,! deepe/ m9es ext5d to little m ?an half-a-mile f ! surface1 & ! deepe/ bor+s to little m ?an ?ree-qu>t]s ( a mile1 :ile ! di/ance f ! e>?'s surface to its c5tre is ne>ly #d1jjj miles4 ,we may well pause be=e we ext5d conclusions1 d]iv$ f su* v limit$ obs]vations1 to su* enorm\s dep?s4 ,b :5 we exam9e critically ^! obs]vations !mselves1 we %all f9d equal gr\nds = caution 9 g5]alis+ f !m4 ,!re is ! greate/ & mo/ />tl+ div]g5ce 9 ! results ( ! obs]vations :i* h be5 made at diff]5t po9ts at ! e>?'s surface4 ,ev5 :5 e all[ance is made = errors ( obs]vation1 ^! discrepancies /ill rema94 ,9 "s places ! increase ( temp]ature z we g d[nw>ds is s rapid t x am\nts to #a ,fahr5heit = e #bj feet 9 dep?1 :ile 9 o!r cases1 9 ord] to obta9 ! same increase 9 temp]ature ( #a ,fahr5heit1 we h to desc5d z mu* z #ajj feet4 ,n[ if1 z is s (t5 assum$1 ?is increase ( temp]ature z we g d[nw>ds be due to our approa* to inc&esc5t masses =m+ ! int]ior portions ( ! globe1 x is difficult to und]/& :y great] uni=mity is n exhibit$ 9 ! rate ( increase 9 diff]5t areas4 ,no diff]5ce 9 ! conduct+ p[]s ( ! v>i\s rock-mat]ials is suffici5t to acc\nt = ! fact t 9 "s places ! rate ( increase 9 temp]ature 9 go+ d[nw>ds is no less ?an five times z great z x is 9 o!rs4 ,sid5ote3 ,,v>iations ,,9 ,,und]gr\nd ,,temp]atures4 ,aga91 !re are "s rem>kable facts conc]n+ ! v>iation 9 ! rate ( increase 9 temp]ature ) dep? :i* seem equally irreconcilable ) ! !ory t ! heat 9 "q is directly d]iv$ f a great1 c5tral1 inc&esc5t mass4 ,m4 ,walf]d91 by a s]ies ( c>eful obs]vations 9 two %afts at ,creuzot1 prov$ t d[n to ! dep? ( #a1hjj feet ! increase ( temp]ature am\nt$ to #a ,fahr5heit = e #ee feet ( desc5t1 b bel[ ! dep? nam$1 ! rate ( increase 0 z mu* z #a ,fahr5heit = e #dd feet4 ,on ! o!r h&1 9 ! great bor+ ( ,gr5elle at ,p>is1 ! increase 9 temp]ature d[n to ! dep? ( #gdj feet am\nt$ to #a ,fahr5heit = e #ej feet ( desc5t1 b f #gdj feet d[n to #a1fjj feet1 ! rate ( increase dim9i%$ to #a = #ge feet ( desc5t4 ,! same rem>kable fact 0 /rik+ly %[n 9 ! case ( ! deepe/ bor+ 9 ! _w--t ( ,sp]5b]g1 ne> ,b]l91 :i* atta9$ ! great dep? ( #d1jeb feet4 ,9 ?is case1 ! rate ( increase 9 temp]ature = ! fir/ #a1ijj feet1 0 #a ,fahr5heit = e #ee feet ( desc5t1 & = ! next #b1jjj1 x dim9i%$ to #a ,fahr5heit = e #fb feet ( desc5t4 ,9 ! deep well ( ,buda-,pe/h !re 0 actually f\nd a decl9e 9 temp]ature bel[ ! dep? ( #c1jjj feet4 ,p]haps ! mo/ int]e/+ fact 9 connection ) ?is "q :i* has be5 discov]$ ( late ye>s1 is t 9 di/ricts :i* h rec5tly be5 ! seat ( volcanic ag5cies1 ! rate ( increase 9 temp]ature1 z we g d[nw>ds 9 ! e>?'s cru/1 is abnormally high4 ,?us at ,monte ,massi 9 ,tuscany1 ! temp]ature 0 f\nd to increase at ! rate ( #a ,fahr5heit = e #bd feet ( desc5t4 ,9 ,hung>y sev]al deep wells & bor+s h be5 made1 :i* prove t a v rapid increase ( temp]ature occurs4 ,! deep bor+ at ,buda-,pe/h p5etrates to a dep? ( #c1afj feet1 & a temp]ature ( #agh ,fahr5heit has be5 obs]v$ ne> ! bottom4 ,! rate ( increase ( temp]ature 9 ?is bor+ 0 ab\t #a = e #bc feet ( desc5t4 ,9 ! m9es op5$ 9 ! great ,com/ock lode1 9 ! we/]n t]ritories ( ! ,unit$ ,/ates1 an abnormally high temp]ature has be5 met ) am\nt+ 9 "s cases to #aeg ,fahr5heit4 ,al?\gh ?is is ! ri*e/ m9]al-ve9 9 ! _w1 hav+ yield$ s9ce #ahei1 :5 x 0 fir/ discov]$1 #fj1jjj1jjjl4 wor? ( gold & silv]1 ?is rapid increase 9 temp]ature 9 go+ d[nw>ds ?reat5s 9 ! end to entirely baffle ! ent]prise ( ! m9]4 ,! rate ( increase 9 temp]ature 9 ! case ( ! ,com/ock m9es has be5 e/imat$ at #a ,fahr5heit = e #df feet ( desc5t1 betwe5 #a1jjj & #b1jjj feet f ! surface1 b z mu* z #a ,fahr5heit = e #be feet1 at dep?s bel[ #b1jjj feet4 ,! facts :i* we h /at$1 ) o!rs ( a simil> k9d1 h l$ geologi/s to look ) grave feel+s ( d\bt ^u ! old hypo!sis :i* reg>d$ ! increase ( temp]ature f\nd 9 mak+ excavations into ! e>?'s cru/ z a pro( t we are approa*+ a great inc&esc5t nucleus4 ,!y h ?us be5 l$ to enquire :e!r !re are any conceivable s\rces ( high temp]atures at mod]ate dep?s--temp]atures :i* w\ld be q compet5t to produce locally all ! ph5om5a ( volcanic action4 ,!re are n want+ o!r facts :i* seem to po9t to ! same conclusion3 namely1 t volcanic action is n due to ! exi/5ce ( a univ]sal res]voir ( inc&esc5t mat]ial occupy+ ! c5tral portion ( our globe1 b to ! local developm5t ( high temp]atures at mod]ate dep?s f ! surface4 ,sid5ote3 ,,dep?s ,,at ,,:i* ,,e>?quakes ,,orig9ate4 ,! close connection betwe5 ! ph5om5a ( volcanoes & e>?quakes _c be d\bt$4 ,x is true t "s ( ^? vibrations or tremors ( ! e>?'s cru/1 to :i* we apply ! "n ( e>?quakes1 occur 9 areas :i* are n n[ ! seat ( volcanic action2 & x is equally true t ! /ratifi$ rock-masses ( our globe1 f> away f any volcanic c5tres1 exhibit pro(s ( viol5t movem5t & fracture1 9 ! production ( :i*1 concussions giv+ rise to e>?quake vibrations1 c\ld sc>cely fail to h occurr$4 ,b x is none ! less c]ta9 t e>?quakes z a rule take place 9 ^? areas :i* are ! seats ( volcanic action1 & t great e>?quake-%ocks prec$e & accompany volcanic outbur/s4 ,sometimes1 too1 x has be5 notic$ t ! manife/ation ( activity at a volcanic c5tre is m>k$ by ! sudd5 decl9e ( ! e>?quake-tremors ( ! di/rict ar\nd1 z ?\gh a safety-valve _h be5 op5$ at t "p ( ! e>?'s surface4 ,mr4 ,mallet has %[n t by ! c>eful /udy ( ! effects produc$ at ! surface by e>?quake-vibrations1 we may det]m9e ) consid]able accuracy ! po9t at :i* ! %ock or concussion occurr$ :i* gave rise to ! vibration4 ,n[ x is a mo/ rem>kable fact t su* calculations h l$ to ! conclusion t1 s f> z is at pres5t kn[n1 e>?quake %ocks nev] orig9ate at great] dep?s ?an ?irty miles f ! surface1 & t 9 "s cases ! focus f :i* ! waves ( ela/ic compression produc+ an e>?quake proce$ is only at ! dep? ( sev5 or eight miles4 ,z we h already se51 !re c be no d\bt t 9 ! great majority ( in/ances ! =ces orig9at+ e>?quake-vibrations & volcanic outbur/s are ! same1 & indep5d5t l9es ( reason+ h conduct$ u to ! conclusion t ^! =ces op]ate at v mod]ate di/ances f ! e>?'s surface4 ,"u ^! circum/ances1 geologi/s h be5 l$ to enquire :e!r !re are any means by :i* we c conceive ( su* an am\nt ( heat1 z w\ld be compet5t to produce volcanic outbur/s1 be+ locally develop$ at c]ta9 po9ts )9 ! e>?'s cru/4 ,rec5t discov]ies 9 physical sci5ce :i* h %[n ! close relation to "o ano!r ( diff]5t k9ds ( =ce1 & _! mutual conv]tibility1 h at lea/ sugge/$ ! possibility ( ! exi/5ce ( causes by :i* su* high temp]atures )9 c]ta9 portions ( ! e>?'s cru/ may be orig9at$4 ,sid5ote3 ,,davy',s ,,*emical ,,!ory4 ,:51 at ! comm5cem5t ( ! pres5t c5tury1 ,sir ,humphry ,davy discov]$ ! rem>kable metals ( ! alkalies & alkal9e e>?s1 & at ! same "t demon/rat$ ! /rik+ ph5om5a :i* are exhibit$ if ^! metals be p]mitt$ to unite ) oxyg51 he at once p]ceiv$ t if su* metals exi/$ 9 an uncomb9$ condition )9 ! e>?'s cru/1 ! access ( wat] & air to ! mass might give rise to ! developm5t ( su* an am\nt ( heat1 z w\ld be compet5t to produce volcanic ph5om5a at ! surface4 ,x is true t at a lat] date ,davy recognis$ ! *emical !ory ( volcanoes z be+ beset ) consid]able difficulties1 & 0 dispos$ to ab&on x altoge!r4 ,x 0 argu$1 ) consid]able %[ ( reason1 t if ! heat at volcanic c5tres 7 produc$ by ! access ( wat] to metallic sub/ances1 great quantities ( hydrog5 w\ld necess>ily be evolv$1 & ?is gas ought to be f\nd 9 prodigi\s quantities among ! emanations ( volcanoes4 ,! fact t su* enorm\s quantities ( hydrog5 gas are n emitt$ f volcanic v5ts has be5 held by _m au?ors to be fatal to ! *emical !ory ( volcanoes4 ,b ! lat] rese>*es ( ,graham & o!rs h made kn[n facts :i* g f> t[>ds supply+ an answ] to ! objections rais$ aga9/ ! *emical !ory ( volcanoes4 ,v>i\s solids & liquids h be5 %[n to possess ! p[] ( absorb+ _m times _! volume ( c]ta9 gases4 ,among ! gases ?us absorb$ 9 l>ge quantities by solids & liquids1 hydrog5 is v conspicu\s4 ,9 "s cases gases are absorb$ by metals or o!r solids 9 a /ate ( fusion1 & yield$ up aga9 by !m z !y cool4 ,x is a v rem>kable circum/ance t "s meteorites are f\nd to h absorb$ l>ge quantities ( hydrog5 gas1 & ?is is giv5 (f :5 !y are heat$ 9 vacuo4 ,?us x has be5 demon/rat$ t c]ta9 meteorites h conta9$ z mu* z =ty sev5 times _! own volume ( hydrog5 gas4 ,we h already po9t$ out t !re are reasons = believ+ ! int]nal portions ( our globe to be compos$ ( mat]ials simil> to ^? f\nd 9 meteorites4 ,if su* be ! case1 ! access ( wat] to ^! metallic sub/ances may result 9 ! =mation ( oxides1 att5d$ ) a great local developm5t ( heat1 ! hydrog5 :i* is lib]at$ be+ at once absorb$ by ! surr\nd+ metallic sub/ances4 ,t ?is oxidation ( ! metallic sub/ances 9 ! int]ior ( our globe by ! access ( wat] & air f ! surface is cont9ually go+ on1 c sc>cely be d\bt$4 ,we may ev5 look =w>d to a f>-di/ant p]iod :5 ! :ole ( ! liquid & gase\s envelopes ( ! globe %all h be5 absorb$ into its sub/ance1 & our e>? !reby r$uc$ to ! condition 9 :i* we n[ f9d ! moon to be4 ,!re is a second me?od by :i* high temp]atures might be locally develop$ )9 ! e>?'s cru/1 :i* has be5 sugge/$ by ,vose1 ,mallet1 & o!r au?ors4 ,we h good gr\nds = believ+ t ! temp]ature ( our globe is cont9ually dim9i%+ by its radiation ( heat into space4 ,?is cool+ ( our globe is att5d$ by contraction1 :i* results 9 movem5ts ( portions ( its cru/4 ,x may at fir/ sight appe> t su* movem5ts w\ld be s small & insignificant z to be q unwor?y ( notice4 ,b if we take into acc\nt ! va/ size ( our e>? x w be se5 t ! movem5ts ( su* enorm\s masses may be att5d$ ) ! mo/ wond]ful results4 ,x has be5 %[n t if a "p ( ! e>?'s cru/ fifty miles 9 ?ickness 7 to h its temp]ature rais$ #bjj ,fahr5heit1 its surface w\ld be rais$ to ! ext5t ( #a1jjj or #a1ejj feet ,le ,conte has po9t$ out t if we conceive ! conduction ( heat to take place at slightly diff]5t rates along diff]5t radii ( our globe1 we %\ld at once be able to acc\nt = ! exi/+ inequalities ( ! e>?'s surface1 & = all ^? cont95tal movem5ts :i* c be %[n to h tak5 place 9 pa/ geological p]iods4 ,sid5ote3 ,,dynamical ,,!ories4 ,b if we admit1 z we h good gr\nds = do+1 t ! loss ( heat f ! ext]nal portions ( our globe goes on m rapidly ?an 9 ! case ( ! c5tral masses1 we h !reby introduc$ ano!r p[]ful ag5t = ! production ( high temp]atures )9 ! e>?'s cru/4 ,! ext]nal %ell ( ! globe w t5d to contract ^u ! c5tral mass1 & 9 s do+ a s]ies ( tang5tial /ra9s w result :i* w be capable ( fold+ & crumpl+ ! rocks along any l9es ( weakness4 ,t su* cru%+ & crumpl+ has dur+ all geological p]iods tak5 place along l9es ( weakness 9 ! e>?'s cru/1 is prov$1 z we h se51 by ! ph5om5a pres5t$ by m\nta9-ranges4 ,n[ ^! cru%+s1 crumpl+s1 & o!r viol5t movem5ts ( great rock-masses mu/ result 9 ! developm5t ( a va/ am\nt ( heat1 j z ! =c+ d[n ( a break ^u a mov+ :eel produces heat4 ,?is conclusion is /rik+ly confirm$ by ! well-kn[n geological fact t ne>ly all rocks :i* h und]gone great movem5t & contortion are f\nd to pres5t evid5ce ( hav+ be5 subject$ to su* *emical & cry/all9e actions1 z w\ld result f ! developm5t ( a high temp]ature )9 _! mass4 ,sid5ote3 ,,recapitulation ,,( ,,sev]al ,,!ories4 ,let u sum up briefly ! v>i\s me?ods :i* h be5 sugge/$ to acc\nt = ! high temp]atures )9 c]ta9 p>ts ( ! e>?'s cru/ by :i* volcanic ph5om5a are produc$4 ,our globe may be conceiv$ ( z an inc&esc5t liquid mass surr\nd$ by a cool]1 solid %ell4 ,if we reg>d ?is liquid int]ior mass z supply+ directly ! v>i\s volcanic v5ts ( ! e>?1 x mu/ be conc$$ t ! out] %ell is ( comp>atively slight ?ickness4 ,b a/ronom]s are almo/ univ]sally agre$ t su* a ?9 out] %ell & inn] liquid mass are q incompatible ) t rigidity :i* our planet exhibits "u ! attractions ( its neighb\rs4 ,geologi/s are almo/ equally unanim\s 9 reg>d+ ?is hypo!sis ( a liquid nucleus & ?91 solid %ell z contradict$ by ! /ability ( ! conditions :i* h be5 ma9ta9$ dur+ su* long pa/ p]iods1 & :i* exi/ at ! pres5t day4 ,! ext5t & "* ( volcanic action d n indicate a condition ( g5]al in/ability 9 our e>?1 b "o ( /ability subject to small & local int]f]5ces ,! gr&e/ volcanic di/urbances appe> small & insignificant1 if we take into acc\nt ! va/ dim5sions ( ! globe ^u :i* !y are display$4 ,if1 on ! o!r h&1 we consid] ! out] solid %ell to be ( great ?ickness1 we are met by ! difficulty ( acc\nt+ = ! upheaval ( liquid matt] ?r\gh su* va/ ?icknesses ( a solid %ell4 ,! diff]5ces 9 "* ( lavas extrud$ f closely adjo9+ volcanic di/ricts seem equally difficult ( explanation on any !ory ( a c5tral1 fluid nucleus & a solid1 out] %ell4 ,nor is ! di/ribution ( heat )9 ! e>?'s cru/ s uni=m z might be anticipat$1 if ! s\rce ( t heat be a great c5tral mass ( highly heat$ mat]ials4 ,"u ^! circum/ances1 geologi/s & physici/s h enquir$ :e!r any o!r conditions c be imag9$ z exi/+ 9 ! e>?'s int]ior1 :i* w\ld bett] acc\nt = ! obs]v$ ph5om5a ?an does ! hypo!sis ( a liquid nucleus & a solid out] %ell4 ,two su* alt]native hypo!ses h be5 sugge/$4 ,mr4 ,hopk9s1 adopt+ ! !ory t ! e>? has solidifi$ bo? at ! c5tre & its out] surface1 endeav\r$ to expla9 ! occurr5ce ( volcanoes & e>?quakes by suppos+ t cavities ( liquid mat]ial h be5 left betwe5 ! solid nucleus & ! solid %ell1 & ^! cavities full ( liquid mat]ial con/itute ! s\rces f :i* ! exi/+ volcanoes ( ! globe draw _! supplies4 ,b ?is hypo!sis is f\nd to be beset ) _m difficulties :5 we attempt to apply x to ! explanation ( ! ph5om5a ( volcanic action4 ,x entirely fails1 among o!r ?+s1 to acc\nt = ! rem>kable fact t dur+ pa/ geological p]iods ! sc5e ( volcanic action has be5 cont9ually %ift+ ov] ! surface ( ! e>?1 s t !re is probably no consid]able area ( our globe :i* has n at "o "t or o!r be5 invad$ by ! volcanic =ces4 ,by "s o!r !ori/s1 :o h felt ! full =ce ( ?is la/ objection1 an attempt has be5 made to expla9 ! ph5om5a ( volcanoes by suppos+ t ! globe is solid f its surface to its c5tre1 b t ! int]nal portions ( ! globe are at su* a high temp]ature t !y are only reta9$ 9 a solid condition by ! enorm\s pressure to :i* !y are subject$4 ,! c5tral masses ( ! globe are ?us reg>d$ z be+ 9 an actually solid1 b 9 a pot5tially liquid condition1 & any local relief ( pressure is at once foll[$ by ! conv]sion ( solid to liquefi$ mat]ials1 9 ! di/rict :]e ! relief takes place1 result+ 9 ! manife/ation ( volcanic ph5om5a at ! spot4 ,x may be grant$ t ?is hypo!sis bett] accords ) ! kn[n facts ( ,vulcanology ?an any ( ^? :i* we h previ\sly describ$1 b x is impossible to %ut our eyes to ! fact t n a few s]i\s difficulties /ill rema94 ,?us x is bas$ ^u ! assumption t ! law ( ! elevation ( ! po9t ( fusion by pressure is true at temp]atures & pressures almo/ inf9itely above ^? at :i* we are able to conduct obs]vations2 b nei!r exp]im5t nor analogy w>rant ?is conclusion1 = ! =m] %[s t ! elevation ( ! po9t ( fusion by pressure goes on 9 a cont9ually dim9i%+ ratio1 & ! latt] fami%es u ) ! example ( volatile liquids :i*1 above _! critical po9ts1 ob/9ately rema9 9 a gase\s condition "u ! highe/ pressures4 ,nor is x easy ^u ?is hypo!sis to acc\nt = ! v irregul> di/ribution ( temp]atures )9 ! e>?'s cru/1 z demon/rat$ by obs]vations 9 m9es1 wells1 & bor+s4 ,! hypo!sis fur!r requires ! assumption t1 at su* v mod]ate dep?s z are requir$ = ! res]voirs ( volcanoes1 ! effects ( pressure & temp]ature on ! condition ( rock-mat]ials are s nicely balanc$ t ! smalle/ *anges at ! surface lead to a di/urbance ( ! equilibrium4 ,sid5ote3 ,,difficulties ,,n ,,yet ,,expla9$4 ,x is ! weight ( ^! sev]al objections t has l$ geologi/s 9 rec5t ye>s to reg>d ) great] fav\r ^? hypo!ses :i* seek to acc\nt = ! production ( high temp]atures )9 p>ts ( ! e>?'s cru/1 )\t hav+ rec\rse to a suppos$ inc&esc5t nucleus4 ,if x c be %[n t !re are any *emical or me*anical =ces at "w )9 ! cru/ ( ! globe :i* are capable ( produc+ local elevations ( temp]ature1 !n we may conceive ( a condition ( ?+s exi/+ 9 ! e>?'s int]ior :i* is free f ! objections rais$ by ! a/ronom] on ! score ( ! e>?'s prov$ rigidity1 & by ! geologi/ on ! gr\nd ( its g5]al /ability1 & :i* at ! same "t seems to h>monise bett] ) ! obs]v$ facts ( ! di/ribution ( temp]ature )9 ! e>?'s cru/4 ,h[ f> ! exi/5ce ( su* *emical & me*anical ag5cies capable ( produc+ high temp]atures )9 ! cru/ ( ! globe h be5 sub/antiat$1 we h already endeav\r$ to po9t out4 ,x mu/ be admitt$1 !n1 t ! que/ions ( ! nature ( ! e>?'s int]ior & ! cause ( ! high temp]atures :i* produce volcanic ph5om5a1 are /ill op5 ones4 ,we h n yet got beyond ! /age ( endeav\r+ to acc\nt = ! facts obs]v$ by means ( t5tative hypo!ses4 ,"s ( ^!1 z we h se51 agree ) ! facts1 s f> z !y are at pres5t kn[n1 mu* bett] ?an o!rs2 b ! decision betwe5 !m or ! rejection ( ! :ole ( !m 9 fav\r ( "s new hypo!sis1 mu/ dep5d on ! results ( future obs]vation & enquiry4 ,x may be well1 be=e leav+ ?is subject1 to rem>k t !y are all equally reconcilable ) ! nebul> !ory ( ,kant & ,laplace4 ,grant+ t ! matt] compos+ our globe has pass$ successively ?r\gh ! gase\s & liquid conditions1 x is op5 to u to imag9e ! e>? z n[ compos$ ( a liquid nucleus ) ei!r a ?ick or a ?9 solid %ell2 ( a solid nucleus & a solid %ell ) m or less liquid matt] betwe5 !m2 or1 la/ly1 to conceive ( x z hav+ become p]fectly solid f ! c5tre to ! surface4 ,sid5ote3 ,,cause ,,( ,,! ,,pres5ce ,,( ,,wat] ,,9 ,,lavas4 ,b x is n ^u ! exi/5ce ( a high temp]ature )9 c]ta9 p>ts ( ! e>?'s cru/ t ! production ( volcanic activity alone dep5ds4 ,! pres5ce ( wat] & o!r liquid & gase\s sub/ances 9 a /ate ( ! mo/ intimate admixture ) ! fus$ rock-masses1 is1 z we h se51 ! ma9 cause ( ! viol5t displays ( en]gy exhibit$ at volcanic c5tres4 ,& ,we %all n[ proce$ to notice ! hypo!ses :i* h be5 sugge/$ to acc\nt = ! pres5ce ( ^! liquid & gase\s bodies 9 ! mid/ ( ! masses ( inc&esc5t mat]ials p\r$ out f volcanic v5ts4 ,!re is an explanation ( ?is pres5ce ( wat] & v>i\s gases 9 ! masses ( molt5 rock-mat]ials )9 ! e>?'s cru/ :i* at once sugge/s itself1 & :i* 0 =m]ly v g5]ally accept$4 ,volcanoes1 z we h se51 are usually situat$ ne> coa/-l9es1 & if we imag9e fissures to be produc$ by :i* sea-wat] f9ds access to masses ( inc&esc5t rock-mat]ials1 !n we c reg>d volcanic outbur/s z result+ f ?is meet+ ( wat] ) rock-masses 9 a highly heal$ condition4 ,?is supposition has be5 ?\ght to receive mu* support f ! fact t _m ( ! gases evolv$ f volcanic v5ts are su* z w\ld be produc$ by ! decomposition ( sub/ances pres5t 9 sea-wat]4 ,b x frequ5tly happ5s t an explanation :i* at fir/ sight appe>s to be v simple & obvi\s1 turns out on m critical exam9ation to be q ! rev]se1 & ?is is ! case ) ! suppos$ orig9ation ( volcanic outbur/s by ! access ( sea-wat] to inc&esc5t rock-mat]ial by means ( e>?-fissures4 ,x is difficult to und]/& h[1 by su* means1 t wond]fully intimate union betwe5 ! liquefi$ rock & ! wat]1 evolv$ 9 su* quantities dur+ volcanic outbur/s1 c\ld be br\ght ab\t2 & moreov]1 we c sc>cely reg>d ! production ( fissures 9 ! e>?'s cru/ z be+ at ! same "t bo? ! cause & ! effect ( ?is influx ( wat] to ! deep-seat$ rock-masses at a high temp]ature4 ,sid5ote3 ,,absorption ,,( ,,gases ,,by ,,liquids ,,& ,,solids4 ,dur+ rec5t ye>s ! att5tion ( bo? geologi/s & physici/s has be5 direct$ to a rem>kable prop]ty exhibit$ by _m liquids & solids1 z supply+ a possible explanation ( ! ph5om5a ( volcanic action4 ,! prop]ty to :i* we ref] is t :]eby "s liquid & solid sub/ances are able to absorb _m times _! volume ( c]ta9 gases--:i* gases "u diff]5t conditions may be giv5 (f aga9 f ! liquids or solids4 ,?is p[] ( absorption is a v rem>kable "o2 x is n att5d$ ) *emical comb9ation1 b ! am\nt ( cond5sation :i* gases mu/ und]go )9 ! solid or liquid sub/ances is sometimes enorm\s4 ,wat] may be made to absorb m ?an #a1jjj times its volume ( ammonia1 & m ?an #ejj times its volume ( hydro*loric acid4 ,alcohol may absorb m ?an #cjj times its volume ( sulphur\s acid4 ,*>coal may absorb #ajj times its volume ( ammonia1 #he times its volume ( hydro*loric acid1 #fe times its volume ( sulphurett$ hydrog51 #ee times its volume ( sulphur\s acid1 & #ce times its volume ( c>bonic acid4 ,plat9um-black absorbs _m times its volume ( oxyg5 & o!r gases4 ,?is p[] ( absorption ( gases v>ies 9 diff]5t solids & liquids accord+ to ! conditions to :i* !y are subject$4 ,dr4 ,h5ry %[$ x to be a g5]al law 9 liquids t1 z ! pressure is augm5t$1 ! weight ( ! gas absorb$ is proportionately increas$4 ,sometimes ?is absorption ( gases takes place only at high temp]atures4 ,?us silv] 9 a /ate ( fusion is able to absorb #bb times its volume ( oxyg5 gas4 ,:5 ! metal is all[$ to cool ?is gas is giv5 (f1 & if ! cool+ takes place sudd5ly a cru/ is =m$ on ! surface1 & ! ph5om5on kn[n z ! 'spitt+ ( silv]' is exhibit$4 ,sometimes dur+ ?is op]ation m9iature cones & lava-/reams are =m$ on ! surface ( ! cool+ mass1 :i* pres5t a /rik+ resemblance to ^? =m$ on a gr& scale ^u ! surface ( ! globe4 ,simil> ph5om5a are exhibit$ by sev]al o!r metals & by ! oxide ( lead4 ,! rese>*es ( ,troo/ & o!rs h %[n t molt5 iron & /eel possess ! prop]ty ( absorb+ consid]able quantities ( oxyg51 hydrog51 c>bonic acid1 & c>bonic oxide1 & t ^! gases are giv5 (f 9 ! op]ation kn[n z 'see?+1' :5 ei!r ! pressure or ! temp]ature is dim9i%$4 ,ho*/ett] has %[n t 9 ! process ( extract+ sulphur f ! residues obta9$ dur+ ! manufacture ( soda1 "s v int]e/+ ph5om5a are manife/$4 ,! molt5 sulphur is expos$ to a temp]ature ( #bfb ,fahr5heit1 & a pressure ( two or ?ree atmosph]es1 9 ! pres5ce ( /eam2 "u ^! circum/ances x is f\nd t ! sulphur absorbs a consid]able quantity ( wat]1 :i* is giv5 (f aga9 ) great viol5ce f ! mass z x und]goes solidification4 ,! h>d5$ cru/ :i* =ms on ! surface ( ! molt5 sulphur is agitat$ & fissur$1 m9iature cones & lava-/reams be+ =m$ ^u x1 :i* h a /rik+ resemblance to ! gr&] ph5om5a ( ! same k9d exhibit$ ^u ! cru/ ( ! globe4 ,! obs]vations :i* we h describ$ prove conclusively t _m liquids & solids 9 a molt5 condition h ! p[] ( absorb+ _m times _! volume ( c]ta9 gases1 & t ?is action is aid$ by heat & pressure4 ,t ! molt5 mat]ials :i* issue f volcanic v5ts h absorb$ enorm\s quantities ( /eam & o!r gases1 we h ! mo/ undisputable evid5ce4 ,! volume ( su* gases giv5 (f dur+ volcanic outbur/s1 & :ile ! lava-/reams are fl[+ & consolidat+1 is enorm\s1 & c only be acc\nt$ = by suppos+ t ! masses ( fluid rock h absorb$ _m times _! volume ( ! gases4 ,b we h ano!r n less conv9c+ pro( ( ! same fact 9 ! circum/ance t volcanic mat]ials :i* h consolidat$ "u great pressure--su* z granites1 gabbros1 porphyries1 c4--exhibit 9 _! cry/als innum]able cavities conta9+ simil> gases 9 a liquefi$ /ate4 ,x is to ! viol5t escape ( ^! gases f ! molt5 rock-masses1 z ! pressure ^u !m is reliev$1 t ne>ly all ! active ph5om5a ( volcanoes mu/ be ref]r$2 & x 0 ! recognition ( ?is bet by ,spallanzani1 :ile he 0 wat*+ ! ph5om5a display$ 9 ! crat] ( ,/romboli1 :i* laid ! f\ndations ( ! sci5ce ( ,vulcanology4 ,sid5ote3 ,,s\rce ,,( ,,! ,,absorb$ ,,gases4 ,b "h ano!r "q pres5ts itself to ! inve/igator ( ! ph5om5a ( volcanoes3 x is ?is4 ,at :at p]iod did ! molt5 rock-masses issu+ f v5ts absorb ^? gase\s mat]ials :i* are giv5 (f s viol5tly f _! mid/ dur+ eruptions8 ,two diff]5t answ]s to ?is "q h be5 sugge/$4 ,x may be t ! orig9al mat]ials ( :i* our globe 0 compos$ consi/$ ( metallic sub/ances 9 a /ate ( fusion :i* _h absorb$ _m gases1 & t1 9 ! fluid masses bel[ ! solid cru/1 va/ quantities ( vap\r & gas are /or$ up1 :i* are be+ gradually add$ to ! atmosph]e dur+ volcanic outbur/s4 ,! fact t meteorites1 :i*1 z we h se51 9 all probability closely resemble ! mat]ials =m+ ! e>?'s int]ior1 sometimes yield _m times _! volume ( hydrog5 & o!r gases1 may be ?\ght to l5d "s support to ?is idea4 ,if x be ! correct "o1 we mu/ reg>d our globe z gradually p>t+ ) its p5t-up /ores ( en]gy1 9 ^? absorb$ gases & vap\rs held 9 bondage by ! solid & fluid mat]ials ( its int]ior4 ,b !re is ano!r hypo!sis :i* is1 to say ! lea/1 equally probable4 ,wat] conta9+ v>i\s gases 9 solution is cont9ually f9d+ its way d[nw>ds by infiltration into ! e>?'s cru/4 ,mu* ( ?is wat]1 aft] pass+ ?r\gh p]vi\s b$s1 rea*es "s imp]vi\s /ratum & is return$ to ! surface 9 ! =m ( spr+s4 ,b t "s ( ?is p]colat+ wat] p5etrates to enorm\s dep?s is %[n by ! fact t ! deepe/ m9es & bor+s enc\nt] va/ und]gr\nd supplies ( wat]4 ,:5 we rememb] t ne>ly ?ree-f\r?s ( ! e>?'s surface is cov]$ by ! wat]s ( ! ocean1 & t ! av]age dep? ( ^! oceanic wat]s is m ?an #aj1jjj feet1 we may easily und]/& h[ great a portion ( ! e>?'s cru/ mu/ be p5etrat$ by infiltrat+ wat]s :i* c f9d no outlet 9 spr+s4 ,! p5etration ( ! wat]s ( ! ocean into ! e>?'s cru/ w be aid$1 too1 by ! enorm\s pressure am\nt+ to n less ?an sev]al tons to ! squ>e-in* ^u ! great] "p ( ! ocean-floor4 ,x might be ?\ght t ?is d[nw>d p5etration ( wat] w\ld be c\nt]act$ by ! upw>d curr5t ( /eam t w\ld be produc$ z ^! subt]ranean wat]s rea* ! hott] portions ( ! e>?'s cru/4 ,b ! exp]im5ts ( ,daubre h conclusively %[n t ! p5etration ( wat] ?r\gh rocks takes place 9 opposition to ! p[]ful pressure ( /eam 9 ! contr>y direction4 ,h5ce1 we may assume t c]ta9 quantities ( wat]1 conta9+ v>i\s gases & solids 9 solution1 are cont9ually f9d+ _! way by capill>y infiltration f ! surface to ! deeply seat$ portions ( ! e>?'s cru/1 !re to und]go absorption by ! inc&esc5t rock-masses & to produce oxidation ( "s ( _! mat]ials4 ,sid5ote3 ,,position ,,( ,,! ,,isogeo!rms4 ,! deep-sea s\nd+s ( ! ',*all5g]' h %[n t ! floor ( ! ocean is con/antly ma9ta9$ at a temp]ature b little above t ( ! freez+ po9t ( wat]4 ,?is l[ temp]ature is probably produc$ by ! absorption ( heat f ! e>?'s cru/ by ! wat]s ( ! ocean1 :i* di/ribute x by means ( convection curr5ts on ! gr&e/ scale4 ,h5ce1 ! isogeo!rms1 or l9es indicat+ ! dep?s at :i* ! same mean temp]ature is f\nd )9 ! e>?'s cru/1 are probably depress$ b5ea? ! great ocean-floors1 & rise t[>ds ! l&-masses4 ,x is to ?is circum/ance1 comb9$ ) t ( ! enorm\s pressure ( wat] on ! ocean-b$s1 t we mu/ probably ascribe ! g5]al abs5ce ( volcanoes 9 ! deep seas & _! di/ribution ne> coa/-l9es4 ,we h ?us briefly review$ ! *ief hypo!ses :i* h be5 sugge/$ 9 ord] to acc\nt = ! two great factors 9 all volcanic ph5om5a--namely1 ! pres5ce ( highly heat$ rock-masses )9 ! e>?'s cru/1 & ! exi/5ce ( v>i\s vap\rs & gases 9 a /ate ( mo/ intimate me*anical1 b n *emical1 union ) ^! inc&esc5t mat]ials4 ,x mu/ be admitt$ t we d n at pres5t appe> to h ! means = fram+ a complete & consi/5t !ory ( volcanic action1 b we may hopefully look =w>d to ! "t :5 fur!r obs]vation & exp]im5t %all h remov$ _m ( ! exi/+ difficulties :i* beset ! "q1 & :5 by ! light ( su* future rese>*es unt5able hypo!ses %all be elim9at$ & ! j ones improv$ & e/abli%$4 ,b if we are con/ra9$ to admit t a /udy ( ! obs]v$ ph5om5a & e/abli%$ laws ( volcanic action h n z yet enabl$ u to frame any complete & satisfactory !ory on ! subject1 we _c lose sight ( ! fact t all mod]n speculation ^u ?is "q appe>s to be t5d+ 9 "o def9ite direction4 ,x is e day becom+ m & m cle> t our e>? is b\nd by ties ( ! close/ resemblance to ! o!r memb]s ( t family ( worlds to :i* x belongs1 & t ! mat]ials ent]+ into _! con/itution1 & ! =ces op]at+ 9 all are ! same4 ,we h _h occasion 9 a previ\s *apt] to po9t out t !re are ! /ronge/ gr\nds = believ+ ! int]ior ( our globe to consi/ ( simil> mat]ials to ^? f\nd 9 ! small planet>y bodies kn[n z meteorites4 ,t ! comets are m]ely aggregations ( su* meteorites1 & t ! planets diff] f !m only 9 _! great] dim5sions1 may be reg>d$ z among ! demon/rat$ conclusions ( ! a/ronom]4 ,! mat]ials f\nd mo/ abundantly 9 meteorites & 9 ! int]ior ( our globe are precisely ! same z ^? :i* are prov$ to exi/ 9 an inc&esc5t /ate 9 our sun4 ,h5ce we are l$ to conclude t ! :ole ( ! bodies ( ! sol> sy/em are compos$ ( ! same *emical elem5ts4 ,sid5ote3 ,,eruptive ,,action ,,9 ,,! ,,sun4 ,t ! =ces op]at+ 9 ea* ( ^! di/ant bodies pres5t /rik+ po9ts ( analogy is equally cle>4 ,! sun is ( f> great] dim5sions ?an our e>?1 & is /ill 9 great "p1 if n entirely1 9 a gase\s condition4 ,! great movem5ts 9 ! out] envelopes ( ! sun exhibit$ 9 ! 'sun-spots' & 'sol> prom95ces1' recall to ! m9d ! ph5om5a ( volcanic activity ^u our globe4 ,b ! va/ en]gy /ill exi/+ 9 ! int5sely heat$ mass ( ! sun1 & ! wond]ful mobility ( its gase\s mat]ials1 give rise to appe>ances beside :i* all t]re/rial outbur/s seem to s9k into utt] insignificance4 ,va/ cavities ( su* dim5sions t _m globes ( ! size ( our e>? might be swall[$ up 9 !m are =m$ 9 ! sol> envelopes 9 ! c\rse ( a few days or h\rs4 ,)9 ^! cavities or sun-spots inc&esc5t vap\rs are obs]v$1 ru%+ upw>ds & d[nw>ds ) almo/ inconceivable velocity4 ,! draw+s made by ,sec*i1 & reproduc$ 9 figs4 #hi & #ij1 w give "s idea ( ! appe>ances pres5t$ by ^! great holes 9 ! sol> envelopes4 ,illu/ration3 ,fig4 #hi4--;,a gr\p ( ,sun-spots4 7,aft] ,sec*i47 ,9 fig4 #hi a gr\p ( sun-spots is repres5t$ &1 9 _! circul> outl9es & t5d5cy to a l9e> arrangem5t1 !y c sc>cely fail to rem9d anyone famili> ) volcanic ph5om5a ( t]re/rial crat]s1 ?\gh _! dim5sions are s mu* great]4 ,9 fig4 #ij ! sun-spot repres5t$ %[s ! pres5ce ( l>ge float+ masses ( inc&esc5t mat]ials ru%+ upw>ds & d[nw>ds )9 ! yawn+ gulf4 ,sid5ote3 ,,ph5om5a ,,( ,,sun-,,spots4 ,illu/ration3 ,fig4 #ij4--;,a ,sun-spot1 %[+ ! great masses ( inc&esc5t vap\r ris+ or fall+ )9 x4 7,aft] ,sec*i47 ,illu/ration3 ,fig4 #ia4--,! edge ( a ,sun-spot1 %[+ a portion ( ! prom95t masses ( inc&esc5t gas 7,a71 :i* deta*$ itself at ,e & float$ into ! mid/ ( ! cavity4 ,f fig4 #ia1 tak5 f a draw+ by ,mr4 ,norman ,locky]1 we may und]/& ! movem5ts ( ^! great protub]ances ( inc&esc5t gas :i* are se5 on ! sides ( ! sun-spots4 ,! s-call$ sol> prom95ces pres5t ev5 m /rik+ resemblances to ! volcanic outbur/s ( our globe4 ,two draw+s made by ,mr4 ,norman ,locky] w s]ve to give "s idea ( ! va/ dim5sions ( ^! sol> prom95ces1 & ( ! rapid *anges :i* take place 9 _! =m4 ,illu/ration3 ,fig4 #ib4--;,draw+ ( a ,sol> prom95ce1 made by ,mr4 ,norman ,locky] on ,m>* #ad1 #ahfi1 at #aa ,h4 #e ,m4 ,a4,m4 ,! masses ( inc&esc5t gas 7 e/imat$ z be+ no less ?an #bg1jjj feet 9 height1 yet 9 t5 m9utes !y _h totally *ang$ _! =m & appe>ance1 z %[n 9 fig4 #ic4 ,ev5 /ill m /rik+ are ! *anges record$ by ,pr(essor ,"y1 ( ,new-,hav51 9 a sol> prom95ce1 :i* he obs]v$ on ,septemb] #g1 #ahga4 ,illu/ration3 ,fig4 #ic4--,! same object1 z se5 at #aa ,h4 #ae ,m4 on ! same day4 ,sid5ote3 ,,sol> ,,prom95ces4 ,t a/ronom] describ$ a mass ( inc&esc5t gas ris+ f ! surface ( ! sun to ! height ( #ed1jjj miles4 ,9 less ?an tw5ty-five m9utes he saw ! :ole mass torn to %r$s & bl[n upw>ds1 "s ( ! fragm5ts be+ 9 t5 m9utes hurl$ to ! height ( #bjj1jjj miles above ! sun's surface4 ,! masses ( inc&esc5t gas ?us hurl$ upw>ds 7 ( enorm\s dim5sions1 ! smalle/ be+ e/imat$ z hav+ a great] area ?an ! :ole ( ! ,briti% ,isl&s1 & ! =ce ) :i* !y 7 urg$ upw>ds 0 s great t !y acquir$ a velocity ( #aff miles p] second4 ,! accompany+ woodcut %[s ! successive appe>ances pres5t$ by ?is gr& eruptive outbur/ on ! surface ( ! sun4 ,illu/ration3 ,fig4 #id4--;,draw+s ( a ,sol> prom95ce at f\r diff]5t p]iods on ,sept4 #g1 #ahga4 7,aft] ,"y47 ,sid5ote3 ,,ext9ct ,,volcanoes ,,( ,,! ,,moon4 ,! moon1 :i* is ( f> small] size ?an our e>?1 exhibits on its surface suffici5tly /rik+ evid5ces ( ! action ( volcanic =ces4 ,inde$ ! dim5sions ( ! crat]s & fissures :i* cov] ! :ole visible lun> surface are su* t we _c b inf] volcanic activity to h be5 f> m viol5t on ! moon ?an x is at ! pres5t day ^u ! e>?4 ,?is great] viol5ce ( ! volcanic =ces on ! moon is p]haps acc\nt$ = by ! fact t ! =ce ( gravity on ! surface ( ! moon is only "o-six? ( t at ! surface ( ! e>?2 & ?us ! eruptive en]gy w h a mu* less small] resi/ance to ov]come 9 bur/+ asund] ! solid cru/ & accumulat$ heaps ( eject$ mat]ials on its surface4 ,b ! volcanic action on ! moon appe>s n[ to h :olly ceas$1 & ! abs5ce ( bo? wat] & atmosph]e 9 our satellite sugge/s t ?is ext9ction ( volcanic en]gy may h be5 caus$ by ! complete absorption ( its gase\s envelope4 ,! appe>ance pres5t$ by a portion ( ! moon's surface is %[n 9 fig4 #ie4 ,! sun & ! moon appe> to exhibit two widely sep>at$ extremes 9 ! condition assum$ dur+ ! cool+ d[n f a /ate ( inc&esc5ce ( great globes ( vaporis$ mat]ials4 ,! sev]al planets1 our own among ! numb]1 probably exhibit v>i\s int]m$iate /ages ( consolidation4 ,illu/ration3 ,fig4 #ie4--;,a gr\p ( ,lun> crat]s 7,maurolycus1 ,b>ocius1 etc471 ! l>ge/ be+ m ?an #fj miles 9 diamet]4 ,sid5ote3 ,,eruptive ,,action ,,9 ,,! ,,sun1 ,,e>? ,,& ,,moon4 ,our e>? is1 z we h se51 closely alli$ to ! o!r bodies ( ! sol> sy/em 9 its movem5ts1 its relations1 & its composition2 & a true !ory ( t]re/rial vulcanicity1 :5 x is discov]$1 may be expect$ n only to af=d an explanation ( ! ph5om5a display$ on our own globe1 b to acc\nt = ^? displays ( int]nal en]gy :i* h be5 manife/$ 9 o!r memb]s ( ! same great family ( worlds4 ,,index4 ,! subjects illu/rat$ 9 ! engrav+s are indicat$ by italics1 ! names ( au?ors are 9 ,capitals4 ,,abi*1 cit$1 #abb -- rese>*es (1 #d ,absorption ( gases by liquids & solids1 #ced1 #cee ,acid lavas1 #dh olian ,isl&s4 ,see ,lip>i ,isl&s olus1 orig9 ( my?1 #ce ,africa1 volcanoes (1 #bbg -- ,s\?1 diamonds (1 #adg ,agates1 =mation (1 #aej ,allport1 ,mr41 cit$1 #bei ,alps1 =mation (1 #bib ,alt]$ lavas1 names giv5 to1 #bfa ,am]ica1 volcanoes (1 #bbg ,amygdaloids1 =mation (1 #adj1 #ada ,&esites1 #ej1 #ei ,&esite-volcanoes1 #abf ,&rews1 ,pr(essor1 cit$1 #cba ,anne ,boleyn & ,etna1 #c ,arm/rong1 ,sir ,w41 hydro-electric ma*9e1 #bi ,ar?ur's ,seat1 #bge ,artificial /one1 #ee ,asia1 volcanoes (1 #bbg ,asid]ites1 #caf ,asmanite1 #cad ,a/roni1 crat]-r+ (1 #agj ,atlantic1 volcanoes 91 #bbc ,auv]gne1 brea*$ cones (1 #abc1 fig4 #dj -- d5ud$ cones 91 #abd1 fig4 #db -- incru/+ spr+s (1 #ahd -- puys (1 #aeb1 #bab -- volcanic cones 91 #gi ,,ball-,,&-,,socket /ructure 9 basaltic columns1 #ajg ,b>rancos1 =mation (1 #bji ,basalt1 controv]sy conc]n+ orig9 (1 #bdi ,basalts1 #di1 #ej1 #ei ,basaltic columns ( ,bohemia1 #ajg -- -- ( ,c5tral ,g]many1 #ajg -- -- ( ,monte ,albano1 #ajg -- -- f ! ,giant's ,causeway1 #ajg1 fig4 #bi ,basic lavas1 #dh ,ba?1 hot spr+ (1 #bai ,b5 ,nevis1 #bgd ,bohemia1 volcanoes (1 #abf -- lavas (1 #ajc ,boil+4 ,see ,ebullition ,bonney1 ,pr(essor1 cit$1 #fi1 #aji1 #bei ,boracic acid at volcanic v5ts1 #baf ,b\rbon1 volcano (1 #agf1 figs4 #gd1 #ge ,bracciano1 crat]-lake (1 #agh1 fig4 #gg ,brea*$ cones1 #abc1 fig4 #dj ,babbles ( /eam1 escape f lava1 #ba ,bubbles1 spontane\s movem5t (1 9 liquid cavities1 #fb1 fig4 #h -- -- cause (1 #fe ,bu*1 ,von1 rese>*es (1 #d ,buda-,pe/h1 deep well (1 #cce1 #cda ,bdos ,hegy1 ,transylvania1 #bae ,buns51 cit$1 #bja ,burn+1 does n take place at volcanoes1 #b ,,cad] ,,idris1 #bgd ',cald]as1' =mation (1 #ahj ,cald]a ( ,palma1 #bji ,cambro-,silurian volcanoes ( ,briti% ,isl&s1 #bgd ,campi-,phlegri1 map (1 fig4 #aa -- -- volcanoes (1 #gi -- -- tuff-cones (1 #aah -- -- fissures 91 #aig ,c>bonic acid 9 cavities ( cry/als1 #fc ,c>bonif]\s volcanoes ( ,briti% ,isl&s1 #bge ,c>lsbad1 ,/rudel (1 #bah -- ,/rudel/e9 (1 #ahd ,caspian ,sea1 mud-volcanoes (1 #ahb ,catacecaum5e1 volcano cones 91 #gi ,cause ( proximity ( volcanoes to sea1 #bci ,c5tral ,asia1 volcanoes (1 #bcf -- ,am]ica1 mud-volcanoes1 #ahb -- ,pacific1 volcanoes (1 #bcf ',*all5g]1' ,h4,m4,s41 voyage (1 #gc -- -- s\nd+s (1 #cei ,*ance1 ,messrs41 ( ,birm+ham1 #ee ,*>nwood ,=e/1 anci5t volcanic rocks (1 #bei ,*emical deposits at ,vulcano1 #dd -- -- on surfaces ( lavas1 #aaj -- elem5ts pres5t 9 lavas1 #df -- !ory ( volcanoes1 #cdd1 #cdf ,*iaja di ,luna1 #ajh ,*imborazo1 size (1 #dd -- #aea ,*odi-,b]g1 ,hung>y1 #afa ,citlaltepetl1 view (1 #afi1 fig4 #fi ,coa/-l9es1 proximity ( volcanoes to1 #bbh ,cole1 ,mr4 ,gr5ville1 #aaj ,col\rs ( lavas1 #di ,columns 9 lava1 #aje -- -- dim5sions (1 #aje -- radiat+ 9 intrusive masses1 #acf ,column> /ructure 9 lavas1 #ajd -- -- orig9 (1 #aje ,column> lava-/ream on ! ,ard*e1 #ajg1 fig4 #bh ,combu/ion1 does n take place at volcanoes1 #b ,composite cones1 #abh1 #afa ,com/ock m9es1 temp]ature (1 #cdb ,conc5tric jo9t+ 9 lava1 #ajh1 fig4 #cj ,cones compos$ ( viscid lava1 #abi1 fig4 #dc -- m9iature on lava-/reams1 #ajj1 #aja1 figs4 #be1 #bf -- natural sections (1 #abi -- %ift+ ( axis 91 #afg ,cool9 ,hills1 ,skye1 #add ,cotopaxi1 volcanic du/ (1 #fi -- view (1 #afh1 fig4 #fh ,crat]s1 =mation (1 #hb -- orig9 (1 #afg -- position (1 #afg -- fissur+ ( sides1 #ahj ,crat] ( ,/romboli1 ap]ture at bottom (1 #ae ,crat]-lakes1 =mation (1 #aga -- ( ,agnano1 #aga -- ( ,albano1 #aga -- ( ,av]nus1 #aga -- ( ,bagno1 #aga1 fig4 #ga -- ( ,bols5a1 #aga -- ( ,bracciano1 #aga -- ( ,frascati1 #agc1 #age -- ( ,gu/avila1 #aga1 fig4 #gb -- ( ,laa*1 #aga -- ( ,nemi1 #aga ,crat]-r+s1 =mation (1 #agj ,crat]-r+ ( ,somma1 #agg1 fig4 #gf ,crat]-r+ ( ,pianura1 #agd -- -- ( ,piano di ,qu>to1 #agd -- -- ( ,vall>iccia1 #agd ,creuzot1 %afts at1 #cdj ',critical po9t' ( liquids1 #fc ,cru/ ( globe1 def9ition (1 #cjh ,cry/als 9 lavas1 #ea -- -- =m$ ( cry/allites1 #ed-eg -- -- =m$ 9 subt]ranean res]voirs1 #fj -- -- int]ruption 9 gr[? (1 #fj -- pressure "u :i* =m$1 #fe -- deposit$ on surface ( lava1 #aaj -- porphyritic1 orig9 (1 #bef ,cry/all9e m9]als =m$ b5ea? volcanoes1 #adf1 #adg -- -- eject$ f volcanoes1 #adg ,cry/allis$ m9]als ( volcanoes1 #df ,cry/allites1 aggregates (1 #ed1 ,frontispiece ,cry/allites 9 lavas1 #ec1 ,frontispiece ,crypto-cry/all9e base1 #eg ',cupolas1' #ace ,corral ( ,madeira1 #bji ,,dacites1 #aih ,dana1 ,pr(essor1 ,j4 ,d41 cit$1 #ajj1 #aei1 #bia1 #cja1 #cbg1 #cch1 #cci ,d>w91 ,mr41 cit$1 #bde1 #bdf1 #bga1 #bhi ,daub5y1 cit$1 #ahb ,daubre1 ,m41 cit$1 #adg1 #cae1 #cbj1 #ceh ,daubrelite1 #cad ,davy1 ,sir ,humphry1 *emical !ory ( volcanoes1 #cdd1 #cde ,deccan ( ,india1 #ajc ,d5sity ( ! e>?1 #cjf ,d5ud$ cones & crat]s1 #aeh1 fig4 #ei ,d5udation1 effects (1 on volcanoes1 #aad ,deposits ab\t volcanic fissures1 #db ,detonations at ,vesuvius1 #bf ,devonian volcanoes ( ,briti% ,isl&s1 #bgd ,diorite1 #ei ,dolomieu1 cit$1 #d1 #ci ,duro*]1 cit$1 #bja ,dykes1 =mation (1 #aaf1 #aag1 #bji1 #baj -- /ructure ( rock 91 #baa -- pseudo-1 #aai ,dynamical !ory ( volcanoes1 #cdg1 #cdh ,,e>?',s int]ior1 nature (1 #cji -- -- physical condition (1 #cbe -- -- hypo!sis conc]n+1 #cbh-ccj -- relation to o!r planets1 #caj1 #caa ,e>?quakes1 dep? ( orig9 (1 #cdc1 #cdd -- connection ) volcanoes1 #cdc -- accompany+ ,vesuvian eruption ( #ahgb1 #bg ,ebullition1 comp>$ to volcanic eruptions1 #ai1 #bj ,eifel1 volcanic cones (1 #de ,eject$ blocks1 #de -- mat]ials1 height to :i* ?r[n1 #gb -- -- /ratification (1 #aag-aai ,elem5ts1 pyrox5ic & tra*ytic1 !ory (1 #bja ,elevation-crat]s1 !ory (1 #ace1 #bjj ,errone\s op9ions1 s\rces (1 9 reg>d to volcanoes1 #b ,eruptions1 feeble & viol5t comp>$1 #ca -- pr$iction (1 n possible1 #cb -- int]vals betwe51 #cc -- ( v>y+ int5sity1 #cc -- & b>ometric pressure1 #cf -- effects ( repetition ( f same fissure1 #hj ,eruptive action 9 sun & moon1 #cfj-cfi ,etna1 ideas ( anci5ts conc]n+1 #c -- & ,anne ,boleyn1 #c -- obs]vatory on1 #cg -- size (1 #dd --1 #aea -- eruptions at summit & on flanks1 #bjg ,etna1 dyke & lava-/ream 91 #acc1 fig4 #ed ,etna1 views (1 #afb1 #afc1 figs4 #fb1 #fc ,euganean ,hills1 #aci -- -- volcanoes (1 #bja ,europe1 volcanoes (1 #bbg ,extra-t]re/rial rocks1 #caf ,extra-t]re/rial rocks1 relation to ultra-basic rocks1 #cbb1 fig4 #hh ,,fel/ones1 #bfc ,f]ric-*loride1 mi/ak5 = sulphur1 #da ,fissure on flanks ( ,etna1 #aid1 fig4 #hd ,fissure-eruptions1 #ahh ,fissures1 volcanic cones on1 #aid -- sy/ems (1 #aih ,f+al's ,cave1 #ajf ,flames1 ph5om5a mi/ak5 =1 #b -- at volcanoes1 feebly lum9\s1 #ag -- false appe>ance (1 9 volcanoes1 #ag ,flames at volcanic v5ts1 #da ,fla%+ ligh?\se1 comp>$ to ,/romboli1 #aj ,floods1 accompany+ volcanic outbur/s1 #cj ,=bes1 ,mr4 ,david1 cit$1 #ccg1 #cci ,fossils1 f b5ea? ,vesuvius1 #de -- suppos$ 9 basalt1 #bej ,f\qu1 ,m41 cit$1 #aaj1 #bac ,fum>oles1 gases emitt$ f1 #bac ,fusiyama1 =m (1 #ij1 #aff ,fusiyama1 #agh1 fig4 #gg ,,gabbro1 #ei ,g>d9]'s riv]1 trav]t9e t]races (1 #ahe ,gases emitt$ f volcanoes1 #dj -- -- volcanic v5ts1 #bab-baf ,geanticl9als1 =mation (1 #big ,gems1 =mation (1 #adg -- mode ( occurr5ce1 #adh ,geological cont9uity1 doctr9e (1 #bdg ,geosyncl9als1 =mation (1 #bid ,geys]s1 =mation (1 #bag -- int]mitt5t action (1 #bah -- ( ,colorado1 #ahd1 #bag -- ( ,icel&1 #ahd1 #bag ,giant's ,causeway1 #ajh ,gilb]t1 ,mr4 ,g4 ,k41 cit$1 #bjh ,girg5ti1 mud-volcanoes (1 #ahb ,glass1 =m$ by fusion ( lavas1 #eb ,glasses1 compos$ ( c]ta9 silicates1 #eh ,glassy base1 #eg ,goe!1 cit$1 #aab ,graham ,isle1 #agh1 #agi1 fig4 #gh ,graham1 cit$1 #cde ,gr& ,s>c\i1 ,auv]gne1 #afa ,granite1 #ei ,granite ( ,second>y & ,t]ti>y ages1 #bed ,granitic rocks1 position b5ea? volcanoes1 #ade ,great e>? movem5ts1 nature (1 #bhf ,great volcanic b&s ( ! globe1 #bcb-bcd ,gr5elle1 bor+ (1 #cda ,grey/ones1 #di ,gr\ndmass ( lavas1 #eb ,grotto del ,cane1 #bae ,guevo ,upas1 ,java1 #bae ,guisc>di1 ,pr(essor1 ref]r$ to1 #de ,gu/avila1 crat]-lake (1 #agb1 fig4 #gb ,,hamilton1 ,sir ,w41 rese>*es (1 #d1 #ge1 #hd -- -- obs]vations on ,vesuvius1 #hj ,hannay1 ,mr41 ref]r$ to1 #adg ,h>tley1 ,mr4 ,noel1 ref]r$ to1 #fe ,hawaii1 volcanoes (1 #ajj1 #abe -- -- lava-masses (1 #aei -- -- volcanic eruptions at diff]5t levels1 #cbg ,hebrides1 volcanoes (1 #bga ,h5ry1 ,dr41 cit$1 #cee ,h5ry ,m\nta9s1 ,s\!rn ,utah1 #bjh ,heph/us1 =ge (1 #c ,ho*/ett]1 cit$1 #ace1 #cef ,holosid]ites1 #cae ,hopk9s1 ,mr41 cit$1 #cdi ,hot spr+s1 numb]s (1 #bai ,humboldt1 rese>*es (1 #d ,hung>y1 lavas (1 #if1 #ajc -- volcanoes (1 #abf1 #bja -- deep wells (1 #cda ,hv]fjall1 ,icel&1 #agh1 fig4 #gg ,hydro-electric ma*9e ( ,sir ,w4 ,arm/rong1 #bi ,hypo!sis1 value (1 #cca-ccc ,,ice "u lava ( ,vesuvius 9 #ahgb1 & ( ,etna1 #aaj ,icel&1 volcanic du/ (1 c>ri$ to ,norway1 #gb ,indian ,ocean1 volcanoes 91 #bbi ,insel ,f]d9&ez1 #agh1 #agi1 fig4 #gh ,int]m$iate lavas1 #dh ,int]vals betwe5 ,eruptions1 #cc ,irel&1 nor?-ea/ (1 #ajc ,iron 9 ,ovifak-basalts1 #cai1 fig4 #hg ,iron1 see?+ (1 #cef -- ( ,ovifak1 t]re/rial orig9 (1 #cbj ,is*ia1 eruption 9 #acja1 #afd -- crat]-lake ( ,bagno 91 #agb1 fig4 #ga -- plan (1 #afc1 fig4 #fd -- p>asitic cones 91 #afd1 fig4 #fe ,isl& ( ,b\rbon1 #ic ,isle ,julie1 #agh1 #agi1 fig4 #gh ,isogeo!rms1 #cei ,,janss51 ref]r$ to1 #db ,jo9t-/ructures 9 lava1 #ajd-aaj ,,kamm]b,,hl1 #aab-aad1 fig4 #cc -- section (1 #aad1 fig4 #cd -- section 9 side (1 #aah1 fig4 #cf ,kant1 nebul> hypo!sis (1 #ceb ,kilauea1 volcano (1 #ga1 #ach -- crat] (1 #aha ,k+1 ,mr4 ,cl>5ce1 cit$1 #cja ,,laa*] ,,see1 m9]als eject$ at1 #adi ,lac ,pav51 ,auv]gne1 #aga1 fig4 #gj ',laccolites1' =mation (1 #bjh ,lago di ,bols5a1 #agc1 #age ,lago di ,bracciano1 dim5sions (1 #agb1 #agc ,lake ,av]nus1 #bae ,lapilli1 #gj ,laplace1 nebul> hypo!sis (1 #cbe1 #ceb ,lavas1 action ( acid gases on1 #da -- resemblance to slags1 #df -- *emical elem5ts 91 #df -- oxyg5 91 #dg -- silicon 91 #dg -- proportion ( silica & o!r oxides 91 #dg -- silicates 91 #dg -- acid1 int]m$iate1 basic1 #dh -- specific gravities (1 #di -- col\rs (1 #di -- microscopic /udy (1 #ej -- fusibility (1 #ea -- m9]als 91 #ea -- artificially fus$1 #ea -- cry/als 91 #ea1 #ic -- gr\nd mass (1 #eb -- cry/all9e =ms (1 #ei -- ( ,bohemia1 #ajc -- ( ,hung>y1 #if1 #ajc -- ( ,kilauea1 #ie -- ( ,lip>i1 #if -- ( ,ni$]m5dig1 #ajc -- ( ,vesuvius1 #ajd -- ( ,volvic1 #ie -- ( ,volcano1 #ie -- pres5ce ( wat] ,91 #ajb -- *emical deposits on1 #aaj -- diff]5t fluidity (1 #bjd -- augite & hornbl5de 91 #bfg ,lava1 cascade (1 #ic1 fig4 #ah ,lava-cones1 compos$ ( liquid lava1 #abe -- -- ( viscid lava1 #abf1 #abg -- *>act]s (1 ( liquid lava1 #aei -- -- ( viscid lava1 #afj ,lava-cones1 outl9es (1 #afj1 fig4 #fj ,lava1 9 deep-seat$ res]voirs1 #ach -- consolidation (1 at great dep?s1 #aci ,lava-f\nta9s1 #id ,lava-%eets1 intrusive1 #acf1 #acg1 fig4 #ef ',lava' ornam5ts ( ,naples1 #de ',lava1' sl[-cool+ (1 #aaj -- a bad conductor ( heat1 #aaj -- ice "u1 #aaj ,lava-/reams1 nature ( movem5ts1 #ib -- diff]5ce 9 liquidity (1 #ib -- m9iature cones on1 #ajj1 #aja -- va/ dim5sions (1 #ajb -- /ructure (1 #ajc -- position ( columns 91 #ajf -- s9k+ ( surface (1 #aaa ',lave di fango1' #cj ',lave di fuoco1' #cj ,lawr5cite1 #cad ,laws ( volcanic action1 #ch ,le ,conte1 cit$1 #cdg ,leucite1 abs5ce f anci5t lavas1 #bfh ,lightn+1 accompany+ volcanic outbur/s1 #bh ,l9e> arrangem5t ( volcanic v5ts1 #aia -- -- ( volcanoes1 #bca ,lip>i ,isl&s1 #c1 #ci -- -- fissures 91 #aig -- -- pumice-cones 91 #aed -- -- ord] ( appe>ance ( lavas 91 #bjj -- -- brea*$ pumice-cones 91 #abd1 fig4 #da -- -- map (1 #aib1 fig4 #ha -- -- lavas (1 #if1 figs4 #bj1 #ba ,liquids 9 cavities ( cry/als1 #fc ,liquid cavities 9 lavas1 #fj1 fig4 #g -- -- spontane\s movem5t ( bubbles 91 #fb1 fig4 #h -- -- spontane\s movem5t ( bubbles 91 cause (1 #fe ,locky]1 ,mr4 ,norman1 cit$1 #cbb1 #cfc1 #cfd ,lun> crat]s1 #cfh1 fig4 #ie ,lyell1 ,sir ,*>les1 cit$1 #ace1 #afg1 #aig ,,maccullo*1 cit$1 #bjg1 #bjh ,madeira1 cliff-section 91 #abh1 fig4 #dg ,magmas1 !ory (1 #bja -- objections to1 #bjb1 #bjc ,mallet1 ,mr41 cit$1 #bfi1 #cdc1 #cdf ,mamelons ( ,b\rbon1 #abf1 #abg1 figs4 #de1 #df ,maskelyne1 ,pr(essor1 cit$1 #cad ,massa di ,somma1 de/ruction (1 #bf ,mauna ,loa1 #ach ,metamorphism ar\nd volcanic v5ts1 #ade ,meteorites1 nature (1 #cab -- composition (1 #cac -- m9]als (1 #cad -- classification (1 #cae ,melaphyres1 #bfb ,miascite1 #ei ,mi*el ,lvy1 ,m41 #aaj ,micro-cry/all9e base1 #eh ,microli?s4 ,see ,cry/allites ,microscopic /udy ( lavas1 #ej ,m9]als 9 lavas1 #ea -- ( ,vesuvius1 #df ,m9]al-ve9s1 =mation (1 #adi -- connection ) volcanoes1 #bbj -- nature ( mat]ials 91 #cba ,mis5um1 ,cape (1 section ( tuff-cone (1 #aba1 fig4 #ch ,mod5a1 mud-volcanoes (1 #ahb ,mont ,dore1 section at1 #acj1 fig4 #dh ,monte ,c]boli1 ,tuscany1 #baf ,monte ,massi1 ,tuscany1 well at1 #cda ,monte ,nuovo1 hi/ory ( =mation (1 #gf -- -- description (1 #gg1 #gh1 fig4 #aj -- -- #aeb -- -- crat] (1 #afh -- -- production ( fissure at1 #aij ,monte ,rotondo1 ,tuscany1 #baf ,moon1 effect ( int]nal =ces on1 #cje ,m\nta9s1 all volcanoes n1 #b ,m\nta9-*a9s1 =mation (1 #bia -- -- all ( rec5t date1 #bib ,mud-/reams at volcanoes1 #cj ,mud-volcanoes1 =mation (1 #aha1 #ahb ,mull1 dissect$ volcano (1 #adb-d1 figs4 #eg1 #eh ,muscovite1 abs5ce (1 f mod]n lavas1 #bfh ,,nebul> hypo!sis ( ,laplace1 #cbe1 #ceb -- -- ( ,kant1 #ceb ,new ,zeal&1 geys]s (1 #bag -- -- volcanoes (1 #ace -- -- volcanic cones 91 #gi ,ni$]m5dig1 lava (1 #ajc ,nord5skild1 ,pr(essor1 cit$1 #cah ,,obs]vatory on ,vesuvius1 #bd1 #cg -- on ,etna1 #cg ,obsidian1 #ei ,oceans1 dep? (1 9 volcanic areas1 #bdb ,oceanic isl&s1 volcanoes 91 #bbh ,oliv]1 ,capt4 ,s4 ,p41 #ib ,oldhamite1 #cad ,outl9es ( ,vesuvius1 #hg1 fig4 #ag ,ovifak1 iron-masses (1 #cai ,oxidation ( mat]ials ( globe1 #cbd ,oxyg51 proportion 9 lavas1 #dg ,,pacific1 volcanoes 91 #bbi ,palmi]i1 ,pr(essor1 cit$1 #be1 #cg ,pap&ayang1 eruption (1 #afi ,pap9's dige/]1 nature ( action 91 #bb ,p>asitic cones1 =mation (1 #afa1 #afb1 fig4 #fa ,pele's ,hair1 #ga ,p]litic /ructure1 #aji ,phillips1 ,mr4 ,j4 ,a41 cit$1 #bbj ,phonolites1 #ej1 #ei ,phonolite-volcanoes1 #abf ,photograph ( ,vesuvius eruption1 #bd1 fig4 #e ',p9e-tree1 app5dage ( ,vesuvius1 #bi ,pit*/ones1 porphyritic1 #fj ,plateaux =m$ ( lava-%eets1 #bgj ,pl9y1 ,eld]1 dea? (1 #g ,plombires1 hot spr+s (1 #adg ,plutonic rocks1 #fa ,pompeii1 nature ( mat]ials cov]+1 #aag ,ponza ,isl&s1 #ci ,ponza1 sections 91 #aca1 #acb1 figs4 #ea1 #eb ,porphyrites1 #bfc ,porphyritic pit*/ones1 #fj ,pot5tially liquid rock1 #bej ,pre-,cambrian volcanoes ( ,briti% ,isl&s1 #bgd ,pres5ce ( wat] 9 lavas1 #cec ,pressure "u :i* cry/als 7 =m$1 #fe ,pr$azzo1 anci5t volcano (1 #afe1 fig4 #fg ,propylites1 #aii ,pseudo-dykes1 #aai ,pumice1 h[ =m$1 #fh -- cause ( :ite col\r (1 #ga -- float+ on ocean1 #gc -- on ocean-b$s1 #gc ,pumice-cones1 #aed ,puy de ,p>i\1 ,auv]gne1 #aic1 #aid1 figs4 #hb1 #hc ,puzzolana1 #hi ,,ra91 accompany+ volcanic outbur/s1 #cj ,rate ( movem5t ( lava-/reams1 #ig ,ra?1 ,pr(essor ,vom1 #gb ,r$ clay ( ocean-b$s1 #gd ,r$ ,m\nta9s1 ,skye1 #add ,res]voirs b5ea? volcanoes1 #ade ,rey]1 ,dr4 ,ed41 exp]im5ts (1 #abe1 #afj ,reykjanes1 eruption (1 9 #aghc1 #ajb ,rhyolites1 #ej1 #ei ,ri*?(51 ,von1 cit$1 #aif1 #aii1 #bjj1 #bje ,rocca-,monf9a1 #agh1 fig4 #gg -- --1 #bjd ,rock-masses1 movem5ts (1 #bhh ,rocky ,m\nta9s1 #ajc -- -- volcanoes (1 #bja ,rotomahana1 s9t]-t]races (1 #ahe ,ropy-lavas1 #ih1 fig4 #bd ,,sal9a1 section 91 #acb1 fig4 #ec ,s&wi* ,isl&s1 lavas (1 #abe ,san ,seba/iano1 de/ruction (1 #bf ,san ,/ephano1 section 91 #aca1 fig4 #ej ,santor91 #db ,s>c\i1 ,gr& ,puy (1 #abf1 fig4 #dd ,sci>ra del fuoco1 #ac ,scoria1 h[ =m$1 #fh1 #gj ,scoria-cones1 alt]$ by acid gas1 #aee -- brea*$1 #aef -- *>act]s (1 #aec -- pres]vation (1 #aee -- r$ col\r (1 #aed ,scoria-cone 9 ,vesuvius1 #abb1 fig4 #ci ,scoria-cone ne> ,auckl&1 ,n4 ,z41 #afef1 fig4 #ff ,s*midt1 ref]r$ to1 #aec ,s*reib]site1 #cad ,scrope1 ,mr4 ,p\lett1 cit$1 #e1 #fi1 #ajf1 #ace1 #aih1 #bje1 #bab1 #bch1 #bhi ,sea ( ,az(1 mud-volcanoes (1 #ahb ,sec*i1 ,fa!r1 cit$1 #cfb ,%iant ,isles1 #aje ,silica1 pres5ce 9 lavas1 #dg ,silicates 9 lavas1 #dg ,silicon1 proportion 9 lavas1 #dg ,silice\s s9t]1 deposits (1 #bbj ,silv]1 spitt+ (1 #cee ,silve/ri1 ,pr(essor1 cit$1 #bcj ,simil>ity ( lavas ( diff]5t ages1 #bfj ,s9t]-cones1 =ms (1 #ahc1 fig4 #gi ,skye1 dissect$ volcano (1 #add ,slags1 comp>$ ) lavas1 #df ,smi?1 ,lawr5ce1 cit$1 #cbj ,smoke1 appe>ance (1 due to /eam1 #b ,sn[don1 #bgd ,sol> prom95ces1 #cfd-cff1 figs4 #ib1 #ic1 #id ,solfat>a ( ,naples1 #bad ,solfat>a-/age ( volcanoes1 #bae ,somma1 #acc -- crat]-r+ (1 #hc ,sorby1 ,mr4 ,h4 ,c41 ref]r$ to1 #ei1 #beb ,spallanzani1 e>ly rese>*es (1 #d -- obs]vations on ,/romboli1 #h -- cit$1 #ci1 #cfg ,specific gravities ( lavas1 #di -- -- ( glassy & cry/all9e rocks1 #ei ,spectroscope 9 vulcanology1 #da ,spectrum-analysis1 results (1 #caa ,specul>-iron1 deposit$ on lava-/reams1 #aaj ,sp]5b]g1 bor+ (1 #cda ,sphrulites1 #ed1 ,frontispiece ,sporadosid]ites1 #caf ,/ability ( cru/ ( globe1 #cbf ,/affa1 ,isle (1 #ajf ,/e5/rup1 cit$1 #cai ,/eam-eng9e comp>$ to volcano1 #h ,/eam1 emitt$ by lava ( ,vesuvius1 #bg ,/]nb]g1 ref]r$ to1 #aac ,/4 ,kilda1 #aha ,/okes1 ,pr(essor1 #fe ,/4 ,paul1 ,isl& (1 #ahj ,/romboli1 #db1 #aeh -- ap]tures at bottom ( crat]1 #ae -- appe>ances 9 crat] (1 #af -- -- at night1 #aj -- comp>$ ) ,vesuvius1 #bc -- crat] (1 #ac -- dep5d5ce ( eruptions on atmosph]ic conditions1 #cd -- eruption (1 #ad1 fig4 #d -- g5]al features (1 #aa -- map (1 #aa1 fig4 #b -- obs]vations by ,spallanzani1 #h -- resemblance to fla%+ light1 #aj -- section (1 #ac1 fig4 #h -- s\nd+s ar\nd1 #ab -- vap\r-cl\d above1 #i -- viol5t eruptions (1 #bc ,/rombolian /age1 #bc ,/ufas1 nature (1 #bag ,subm>9e volcanoes1 #agi ,subt]ranean =ces1 b5eficial effects (1 #cjc ,subsid5ce 9 c5tre ( volcanoes1 #afe ,sulphur1 absorption ( wat] by molt51 #cef -- deposit$ on lava-/reams1 #aaj -- h[ =m$ at volcanoes1 #ah -- n ! cause ( volcanic outbur/s1 #ah ,surfaces ( lava-/reams1 #ig-ii1 figs4 #bb1 #bc ,sun-spots1 #cfa-cfc1 figs4 #hi1 #ij1 #ia ,sy5ite1 #ei ,syssid]ites1 #caf ,szabo1 ,pr(essor1 cit$1 #aii ,,ta*ylyte1 #ei ,t]ti>y volcanoes ( ,briti% ,isl&s1 #bgf ,t]races1 s9t]- & trav]t9e-=mation (1 #ahe1 fig4 #hj ,temp]ature1 increase 9 deep] p>ts ( e>?'s cru/1 #cce -- rate ( increase 9 diff]5t areas1 #cdj ,t5]iffe1 #dd1 #aea ,t5]iffe1 #agh1 fig4 #gg -- peak (1 #age1 fig4 #gc ,t5on-&-mortise /ructure 9 basaltic columns1 #ajg ,!odosius & ,vulcano1 #c ,?und]1 accompany+ volcanic outbur/s1 #bh ,tra*ytes1 #di1 #ej1 #fi ,trap-rocks1 orig9 (1 #bda ,trass1 #ij ,trav]t9e or ,tibur-/one1 #ahd -- deposits (1 #bbj ,triassic volcanoes ( ,briti% ,isl&s1 #bge ,tridymite deposit$ on lava-/reams1 #aaj ,troilite1 #cad ,troo/1 cit$1 #cee ,tufa1 or tuff1 #ij ,tuff-cones1 "* (1 #aeg -- d5udation (1 #aeg1 #aeh ,typhon1 fable (1 #c ,,ultra-,,basic lavas1 #ej1 #ff -- rocks1 #cag ,,val ,,del ,,bove1 ,etna1 #acc1 #ahj1 #bji -- -- dykes 91 #acd1 fig4 #ee ,vap\r-cl\d ov] ,vesuvius1 #bf1 #bi -- -- ,/romboli1 #i ,v5toti5ne1 ,isl& (1 section at1 #acj1 fig4 #di ,vesuvius1 #cg -- *anges 9 =m (1 #ha -- comp>$ ) ,/romboli1 #bc -- crat] ( 9 #agef1 #hd1 fig4 #ad -- -- ( 9 #agfg1 #he1 fig4 #af -- -- ( 9 #ahbb1 #hb1 fig4 #ac -- -- ( 9 #ahdc1 #hf1 fig4 #af -- detonations at1 #bf -- e>ly hi/ory (1 #hc -- eruption ( ye> #gi1 #hd -- -- ( #ahbb1 #fi -- -- ( ,april #ahgb1 #bd -- -- ( ,octob] #ahbb1 #bd -- eject$ blocks (1 #de -- fir/ eruption (1 #g -- =m (1 #aff -- fossils (1 #de -- gr[? ( cone (1 #hj -- hi/ory (1 #bjd -- la/ eruption (1 #g -- lava-/ream ( #ahee1 #aja -- lava-/reams ( #aheh1 #ahgb1 #ig -- lavas (1 #ajd -- m9]als (1 #df -- -- eject$ at1 #adi -- obs]vatory on1 #bd1 #cg -- outl9es (1 #hg -- p9e-tree app5dage (1 #bi -- scoria-cones 9 lava1 #abb -- -- on lava ( #ahee1 #aec -- /eam emitt$ by lava (1 #bg -- vap\r-cl\d ov]1 #bf1 #bi ,vesuvian /age1 #bc -- eruption1 photograph (1 #bd1 fig4 #e ,viscid lavas ( ,lip>i ,isl&s1 #id-if ,vitre\s lavas1 devitrification (1 #bei ,volcanic action1 laws (1 #cb -- bombs1 #gj1 #ga -- cycles1 nature (1 #bba1 #bbb -- -- duration (1 #bbc -- cones1 int]nal /ructure (1 #aae-abb -- -- exp]im5tal illu/ration ( =mation (1 #abj1 fig4 #cg -- -- limits to height (1 #aff -- -- =m (1 #aeb -- -- dim5sions (1 #aeb -- -- irregul> developm5t (1 #ij -- -- slopes ( sides (1 #ia -- -- compos$ ( eject$ rock-fragm5ts1 #aef -- -- curv$ slopes (1 #aef -- dbris on sea-bottom1 #bdj -- du/1 f95ess (1 #fi -- di/ricts1 areas ( upheaval1 #bde -- ejections1 alt]ation (1 #beh -- eruptions1 comp>$ to ebullition1 #ai1 #bj -- =ces1 comp5sate = d5udation1 #bhc -- -- int5sity at =m] p]iods1 #bgh -- -- necessity = action (1 #bhe -- -- %ift+ ( f "o area to ano!r1 #bgg -- m\nta9s1 orig9 ( conical =ms1 #hi -- -- mode ( gr[?1 #hi -- ph5om5a ( ! pa/ simil> to ^? at pres5t1 #bgc -- products1 ord] ( appe>ance (1 #aih1 #aii ,volcanic rocks1 #fa -- -- simil>ity ( anci5t & mod]n1 #bec ,volcano1 orig9 ( "n1 #c -- crat]s (1 #afg -- ,isl& (4 ,see ,vulcano4 -- comp>$ to /eam-eng9e1 #h ,volcanoes1 blocks1 eject$ f1 #de -- built up ( eject$ fragm5ts1 #gd -- de/ruction caus$ by1 #bha -- dissect$ by d5udation1 #aae1 #aci -- errone\s ideas conc]n+1 #a -- ejection ( diff]5t mat]ials f1 #bje -- kn[n to anci5ts1 #c -- life-hi/ory (1 #ahf -- numb] (1 #bbd1 #bbe -- ( ,africa1 #bbg -- ( ,am]ica1 #bcf -- ( ,asia1 #bcf -- ( ,bohemia1 #abf -- ( ,c5tral ,asia1 #bcf -- ( ,c5tral ,pacific1 #bcf -- ( ,europe1 #bbg -- ( ,hung>y1 #abf -- position 9 relation to m\nta9 *a9s1 #bdc -- popul> ideas conc]n+1 #a -- res]voirs b5ea?1 #ade ,volvic lava (1 #ajc ,vose1 cit$1 #cdf ,vulcan1 =ge (1 #c ,vulcano1 isl& (1 #c1 #aeh ,vulcano & ,!odosius1 #c ,vulcano1 #agh1 fig4 #gg -- & ,vulcanello1 view (1 #dc1 fig4 #f -- *emical deposits at1 #dd -- eruption 9 #aghf1 #dc -- -- 9 #ahgc1 #dc -- -- lava-/ream 91 #ie1 fig4 #ai -- --1 #ajc1 fig4 #bg -- plan (1 #aie1 fig4 #he -- section ( volcanic cone 91 #aaf1 fig4 #ce -- section 91 #abi -- %ift+ ( c5tre ( eruption 91 #aif ,vulcanello1 crat]s (1 #aig1 fig4 #hf ,vulcanology1 orig9 ( ! sci5ce1 #d -- e>lie/ treatise on1 #e ,walf]d91 ,m41 cit$1 #cdj ,wat] 9 lavas1 #cec -- p5etration ?r\gh rocks1 #ceh -- pres5ce ( 9 lavas1 #ajb -- & sal9e solutions 9 cavities ( cry/als1 #fc ,w]n]1 cit$1 #bja ,we/]n ,isles ( ,scotl&1 #ajc1 #aci1 #adb -- -- volcanoes (1 #bab ,:ymp]1 ,mr41 #fi ,woodw>d1 ,mr41 exp]im5ts (1 #aai ,wrek91 anci5t volcanic rocks (1 #bei ,,"y1 ,pr(essor1 cit$1 #cfe ,,zeolites1 =mation (1 #aej ,,pr9t$ ,,by ,,spottiswoode ,,& ,,co4 ,,ltd41 ,,new-,,/reet ,,squ>e ,,london ,,! ,,int]national ,,sci5tific ,,s]ies4 ,ea* ,book ,complete 9 ,"o ,volume4 ,cr[n #hvo4 clo?1 #es4 unless o!rwise describ$4 ,i4 ,,=ms ( ,,wat]3 9 ,cl\ds & ,riv]s1 ,ice & ,glaci]s4 ,by ,j4 ,tyndall1 ,,ll4,d41 ,f4,r4,s4 ,) #bf ,illu/rations4 ,twelf? 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( ! ,,/eam ,,eng9e4 ,by ,pr(essor ,r4 ,h4 ,?ur/on4 ,) num]\s ,illu/rations4 ,fif? ,edition4 ,,xxv4 ,,education z a ,,sci5ce4 ,by ,alex&] ,ba91 ,,ll4,d4 ,n9? ,edition4 ,,xxvi4 ,! ,,human ,,species4 ,by ,pr(essor ,a4 de ,quatrefages1 ,membre de l',in/itut4 ,fif? ,edition4 ,,xxvii4 ,,mod]n ,,*romatics4 ,) ,application to ,art & ,indu/ry4 ,by ,ogd5 ,n4 ,rood4 ,?ird ,edition4 ,) #acj orig9al ,illu/rations4 ,,xxviii4 ,! ,,crayfi%3 an ,introduction to ! ,/udy ( ,zoology4 ,by ,t4 ,h4 ,huxley1 ,f4,r4,s4 ,six? ,edition4 ,) #hc ,illu/rations4 ,,xxix4 ,! ,,bra9 z an ,,organ ( ,,m9d4 ,by ,h4 ,*>lton ,ba/ian1 ,m4,d4 ,f\r? ,edition4 ,) #ahd ,illu/rations4 ,,xxx4 ,! ,,atomic ,,!ory4 ,by ,pr(essor ,a4 ,wurtz4 ,translat$ by ,e4 ,clem9%aw1 ,f4,r4,s4 ,sev5? ,edition4 ,,xxxi4 ,! ,,natural ,,conditions ( ,,exi/5ce z !y affect ,animal ,life4 ,by ,k>l ,semp]4 ,fif? ,edition4 ,) #c ,maps & #ajf ,woodcuts4 ,,xxxii4 ,,g5]al ,,physiology ( ,,muscles & ,,n]ves4 ,by ,pr(4 ,j4 ,ros5?al4 ,f\r? ,edition4 ,) #ge ,illu/rations4 ,,xxxiii4 ,,sight3 an ,exposition ( ! ,pr9ciples ( ,monocul> & ,b9ocul> ,vision4 ,by ,joseph ,le ,conte1 ,,ll4,d4 ,?ird ,edition4 ,) #acb ,illu/rations4 ,,xxxiv4 ,,illusions3 a ,psy*ological ,/udy4 ,by ,james ,sully4 ,f\r? ,edition4 ,,xxxv4 ,,volcanoes3 :at !y are & :at !y tea*4 ,by ,john ,w4 ,judd1 ,f4,r4,s4 ,fif? ,edition4 ,) #if ,illu/rations4 ,,xxxvi4 ,,suicide3 an ,essay on ,comp>ative ,moral ,/ati/ics4 ,by ,pr(essor ,h4 ,morselli4 ,?ird ,edition4 ,,xxxvii4 ,! ,,bra9 & its ,,functions4 ,by ,j4 ,luys1 ,physician to ! ,hospice de la ,salptrire4 ,) num]\s ,illu/rations4 ,?ird ,edition4 ,,xxxviii4 ,,my? & ,,sci5ce3 an ,essay4 ,by ,tito ,vignoli4 ,f\r? ,edition4 ,,xxxix4 ,! ,,sun4 ,by ,c4 ,a4 ,"y1 ,ph4,d41 ,,ll4,d4 ,fif? ,edition4 ,) num]\s ,illu/rations4 ,,xl4 ,,ants1 ,,bees1 & ,,wasps4 ,a ,record ( ,obs]vations on ! ,habits ( ! ,social ,hym5opt]a4 ,by ,sir ,john ,lubbock1 ,b>t41 ,m4,p4 ,f\rte5? ,edition4 ,) #e ,*romo-li?ographic ,plates4 ,,xli4 ,,animal ,,intellig5ce4 ,by ,george ,j4 ,romanes4 ,,ll4,d41 ,f4,r4,s4 ,six? ,edition4 ,,xlii4 ,! ,,concepts & ,,!ories ( ,,mod]n ,,physics4 ,by ,j4 ,b4 ,/allo4 ,?ird ,edition4 ,london3 ,,kegan ,,paul1 ,,tr5*1 ,,tr,,bn]1 ,,co41 ,ltd4 ,! ,int]national ,sci5tific ,s]ies--cont9u$4 ,,xliii4 ,,diseases ( ,,memory4 ,an ,essay 9 ! ,positive ,psy*ology4 ,by ,?4 ,ribot4 ,f\r? ,edition4 ,,xliv4 ,,man ,,be=e ,,metals4 ,by ,n4 ,joly1 ,correspond5t de l',in/itut de ,france4 ,fif? ,edition4 ,) #adh ,illu/rations4 ,,xlv4 ,! ,,sci5ce ( ,,politics4 ,by ,pr(4 ,%eldon ,amos4 ,?ird ,edition4 ,,xlvi4 ,,elem5t>y ,,meteorology4 ,by ,rob]t ,h4 ,scott4 ,) #aa ,plates & #dj ,figures 9 ,text4 ,sev5? ,edition4 ,,xlvii4 ,! ,,organs ( ,,spee*4 ,by ,georg ,h]mann von ,mey]4 ,) #dg ,illu/rations4 ,,xlviii4 ,,fallacies3 a ,view ( ,logic f ! ,practical ,side4 ,by ,alfr$ ,sidgwick4 ,second ,edition4 ,,xlix4 ,! ,,orig9 ( ,,cultivat$ ,,plants4 ,by ,alphonse ,de ,c&olle4 ,second ,edition4 ,l4 ,,jelly ,,fi%1 ,,/> ,,fi%1 & ,,sea ,,ur*9s4 ,be+ a ,rese>* on ,primitive ,n]v\s ,sy/ems4 ,by ,g4 ,j4 ,romanes1 ,,ll4,d41 ,f4,r4,s4 ,second ,edition4 ,,li4 ,! ,,common ,,s5se ( ! ,,exact ,,sci5ces4 ,by ! late ,william ,k+don ,clif=d4 ,?ird ,edition4 ,) #ajj ,figures4 ,,lii4 ,,physical ,,expression3 its ,modes & ,pr9ciples4 ,by ,francis ,w>n]1 ,m4,d41 ,f4,r4,c4,p4 ,second ,edition4 ,) #ej ,illu/rations4 ,,liii4 ,,an?ropoid ,,apes4 ,by ,rob]t ,h>tmann4 ,) #fc ,illu/rations4 ,second ,edition4 ,,liv4 ,! ,,mammalia 9 _! ,,relation to ,,primeval ,,times4 ,by ,osc> ,s*midt4 ,second ,edition4 ,) #ea ,woodcuts4 ,,lv4 ,,comp>ative ,,lit]ature4 ,by ,h4 ,macaulay ,posnett1 ,,ll4,d4 ,,lvi4 ,,e>?quakes & o!r ,,e>? ,,movem5ts4 ,by ,pr(4 ,john ,milne4 ,) #hh ,figures4 ,f\r? ,edition1 revis$4 ,,lvii4 ,,microbes1 ,,f]m5ts1 & ,,m\lds4 ,by ,e4 ,l4 ,tr\ess>t4 ,) #ajg ,illu/rations4 ,?ird ,edition4 ,,lviii4 ,,geographical & ,,geological ,,di/ribution ( ,,animals ,by ,pr(4 ,a4 ,heilpr94 ,second ,edition4 ,,lix4 ,,wea!r3 a ,popul> ,exposition ( ! ,nature ( ,wea!r ,*anges f ,day to ,day4 ,by ! ,hon4 ,ralph ,ab]cromby4 ,) #if ,figures4 ,f\r? ,edition4 ,,lx4 ,,animal ,,magnetism4 ,by ,alfr$ ,b9et & ,*>les ,fre4 ,f\r? ,edition4 ,,lxi4 ,,manual ( ,,briti% ,,discomycetes1 ) descriptions ( all ! ,species ( ,fungi hi!rto f\nd 9 ,brita9 includ$ 9 ! ,family1 & ,illu/rations ( ! ,g5]a4 ,by ,william ,phillips1 ,f4,l4,s4 ,second ,edition4 ,,lxii4 ,,int]national ,,law4 ,) ,mat]ials = a ,code ( ,int]national ,law4 ,by ,pr(essor ,leone ,levi4 ,,lxiii4 ,! ,,geological ,,hi/ory ( ,,plants4 ,by ,sir ,j4 ,william ,dawson4 ,) #hj ,illu/rations4 ,,lxiv4 ,! ,,orig9 ( ,,floral ,,/ructures ,,?r\gh ,,insect & o!r ,,ag5cies4 ,by ,pr(4 ,g4 ,h5sl[4 ,second ,edition4 ,,lxv4 ,on ! ,,s5ses1 ,,in/9cts1 & ,,intellig5ce ( ,,animals1 ) special ref]5ce to ,,insects4 ,by ,sir ,john ,lubbock1 ,b>t41 ,m4,p4 ,) #aah ,illu/rations4 ,?ird ,edition4 ,london3 ,,kegan ,,paul1 ,,tr5*1 ,,tr,,bn]1 ,,co41 ,ltd4 ,! ,int]national ,sci5tific ,s]ies--cont9u$4 ,,lxvi4 ,! ,,primitive ,,family 9 its ,,orig9 & ,,developm5t4 ,by ,c4 ,n4 ,/>cke4 ,second ,edition4 ,,lxvii4 ,,physiology ( ,,bodily ,,ex]cise4 ,by ,f]n& ,lagrange1 ,m4,d4 ,second ,edition4 ,,lxviii4 ,! ,,col\rs ( ,,animals3 _! ,mean+ & ,use1 especially consid]$ 9 ! case ( ,insects4 ,by ,e4 ,b4 ,p\lton1 ,f4,r4,s4 ,) ,*romoli?ographic ,frontispiece & upw>ds ( #fj ,figures 9 ,text4 ,second ,edition4 ,,lxix4 ,,introduction to ,,fre%-,,wat] ,,alg4 ,) an ,enum]ation ( all ! ,briti% ,species4 ,by ,m4 ,c4 ,cooke1 ,,ll4,d4 ,) #ac ,plates ,illu/rat+ all ! ,g5]a4 ,,lxx4 ,,socialism3 ,,new & ,,old4 ,by ,william ,graham1 ,m4,a41 ,pr(essor ( ,political ,economy & ,jurisprud5ce1 ,que5's ,college1 ,belfa/4 ,second ,edition4 ,,lxxi4 ,,col\r-,,bl9dness & ,,col\r-,,p]ception4 ,by ,f4 ,w4 ,edridge-,gre51 ,m4,d4 ,) #c ,col\r$ ,plates4 ,,lxxii4 ,,man & ! ,,glacial ,,p]iod4 ,by ,g4 ,f4 ,wright1 ,d4,d4 ,) #aaa ,illu/rations & ,maps4 ,second ,edition4 ,,lxxiii4 ,,h&book ( ,,greek & ,,lat9 ,,pal,,ography4 ,by ,sir ,e4 ,maunde ,?ompson1 ,k4,c4,b4 ,) ,tables ( ,alphabets & ,facsimiles4 ,second ,edition4 ,,lxxiv4 ,a ,,hi/ory ( ,,cru/acea3 ,rec5t ,malaco/raca4 ,by ,?omas ,r4 ,r4 ,/ebb+1 ,m4,a4 ,) #ai ,plates & #cb ,figures 9 ,text4 ,,lxxv4 ,! ,,disp]sal ( ,,%ells3 an ,inquiry into ! means ( ,disp]sal possess$ by ,fre% ,wat] & ,l& ,mollusca4 ,by ,h4 ,wallis ,kew1 ,f4,z4,s4 ,) ,preface by ,a4 ,r4 ,wallace1 ,f4,b4,s41 & ,illu/rations4 ,,lxxvi4 ,,race & ,,language4 ,by ,&r ,lefvre1 ,pr(essor 9 ! ,an?ropological ,s*ool1 ,p>is4 ,,lxxvii4 ,! ,,orig9 ( ,,plant ,,/ructures by ,,self-,,adaptation ,,to ,,! ,,environm5t4 ,by ,rev4 ,g4 ,h5sl[4 ,m4,a41 ,f4,l4,s41 ,f4,g4,s41 c41 au?or ( ',! ,orig9 ( ,floral ,/ructures1' c4 ,,lxxviii4 ,,ice-,,"w ,,pres5t & ,,pa/4 ,by ,rev4 ,t4 ,g4 ,bonney1 ,d4,sc41 ,,ll4,d41 ,f4,r4,s41 c41 ,pr(essor ( ,geology at ,univ]sity ,college1 ,london2 ,fell[ ( ,/4 ,john's ,college1 ,cambridge4 ,,lxxix4 ,a ,,contribution to our ,,k ( ,,se$l+s4 ,by ,rt4 ,hon4 ,sir ,john ,lubbock1 ,b>t41 ,m4,p41 ,f4,r4,s4 ,,lxxx4 ,! ,,art ( ,,music4 ,by ,sir ,c4 ,hub]t ,h4 ,p>ry1 ,mus4 ,doc4 ,,lxxxi4 ,! ,,pol> ,,aurora4 ,by ,alfr$ ,angot4 ,illu/rat$4 ,,lxxxii4 ,,:at is ,,electricity8 ,by ,j4 ,tr[bridge4 ,illu/rat$4 ,,lxxxiii4 ,,memory4 ,by ,f4 ,w4 ,edridge-,gre51 ,m4,d4 ,) ,frontispiece4 ,,lxxxiv4 ,! ,,elem5ts ( ,,hypnotism4 ,by ,b4 ,h>ry ,v9c5t4 ,) ,diagrams4 ,second ,edition4 ,,lxxxv4 ,,seismology4 ,by ,john ,milne1 ,f4,r4,s41 ,f4,g4,s41 c41 ,au?or ( ',e>?quakes4' ,) #fc ,figures4 ,,lxxxvi4 ,on ,,buds & ,,/ipules4 ,by ! ,"r ,hon4 ,sir ,john ,lubbock1 ,b>t1 ,m4,p41 ,f4,r4,s41 ,d4,c4,l41 ,,ll4,d4 ,) #d ,col\r$ ,plates & #cdj ,figures 9 ! ,text4 ,,lxxxvii4 ,,evolution by ,,atrophy1 9 ,biology & ,sociology4 ,by ,jean ,demoor1 ,jean ,mass>t1 & ,emile ,v&]velde4 ,translat$ by ,mrs4 ,*alm]s ,mit*ell4 ,) #hd ,figures4 ,london3 ,,kegan ,,paul1 ,,tr5*1 ,,tr,,bn]1 ,,co41 ,ltd4 99 99 99 99 99 ,transcrib] ,note ,m9or typos correct$4 ,li/+ ( ,! ,int]national ,sci5tific ,s]ies 0 split betwe5 ! front & end ( book b are "h mov$ to ! end4 ,! li/ 0 also re=matt$4 ,! captions = ! map key 9 ,figure #eh 7 re=matt$ into a table4 ,figure #da 0 relocat$ z x foll[$ ,figure #db 9 ! pr9t$ v]sion4