---------------------------------------- --------------------------- ,transcrib]'s ,notes3 ,italics are indicat$ by ! und]score "*1 z 9 ^w4 ,bold face is indicat$ by ! equal "*1 z 9 ^w4 ,subscript is indicat$ by subscript4 ,footnotes h be5 mov$ to bel[ ! p>agraph !y ref] to4 ,table ( cont5ts3 #hd-je *ang$ to #hd-ie4 ,p>agraph />t+ ,unit+ ,pieces ( ,glass to ,ea* ,o!r1 kn[n z ,weld+1 or ,sold]+3 footnote an*or #a & numb] #a4 be=e next p>agraph delet$4 ,caption ,,fig4 #ah add$ to illu/ration4 ,p>agraph directly bel[ ,,fig4 #ah3 comma add$ 7or bett]144474 #bnd p>agraph "u ,,fig4 #ai3 ,,de ?r\gh ,e *ang$ to ,,de ?r\gh ,e4 #bnd p>agraph "u ,,fig4 #cd3 :5ce x might gradually lead into *ang$ to :5ce x might gradually leak into4 ,to,c3 sev]al sections add$1 s t all nam$ sections are includ$4 endiomet] *ang$ to eudiomet]4 ,"s m9or typographical errors & inconsi/5cies correct$4 ---------------------------------------- --------------------------- ,,! ,,me?ods ,,( ,,glass ,,bl[+ ,,& ,,( ,,work+ ,,silica ,,by ,,! ,,same ,,au?or ,) #be ,illu/rations4 ,cr[n #hvo1 #bs4 ,a ,practical ,introduction to ,*emi/ry4 ,int5d$ to give a practical acqua9tance ) ! ,elem5t>y ,facts & ,pr9ciples ( ,*emi/ry4 ,,longmans1 ,,gre51 ,,& ,,co4 ,,london1 ,,new ,,york1 ,,bombay1 ,,calcutta1 ,,& ,,madras4 ,! ,me?ods ( ,glass ,bl[+ ,,& ,,( ,work+ ,silica 9 ! ,oxy-,gas ,flame ,,= ,,! ,,use ,,( ,,*emical ,,& ,,physical ,,/ud5ts ,,by ,w4 ,a4 ,,%5/one1 ,f4,r4,s4 ,,=m]ly ,,lectur] ,,on ,,*emi/ry ,,9 ,,clifton ,,college ,,n9? ,,impression ,,longmans1 ,,gre51 ,,& ,,co4 #ci ,,pat]no/] ,,r[1 ,,london ,,f\r? ,,av5ue #cj,,? ,,/reet1 ,,new ,,york ,,bombay1 ,,calcutta1 ,,& ,,madras #aiaf ,,preface ,?is book consi/s ( a repr9t ( ! ?ird edition ( my ,me?ods ( ,glass-bl[+1 toge!r ) a new *apt] 9 :i* ,i h describ$ ! comp>atively new art ( work+ vitre\s silica4 ,! individual op]ations ( glass-bl[+ are mu* less difficult ?an is usually suppos$1 & consid]able success 9 ! p]=mance ( mo/ ( !m may be atta9$ by any "o :o is end[$ ) av]age p[]s ( manipulation & :o is mod]ately p]si/5t4 ,con/ruct+ f9i%$ app>atus is (t5 m difficult1 z x may involve ! p]=mance ( sev]al op]ations "u disadvantage\s conditions1 & may dem& a little +5uity on ! "p ( ! op]ator4 ,b ,i ?9k ! sugge/ions 9 ,*apt] ,,iv4 w make ?is comp>atively easy also to ^? :o h ma/]$ ! op]ations describ$ 9 ,*apt] ,,iii4 ,! work+ ( vitre\s silica1 ?\gh m t$i\s & exp5sive ?an glass-bl[+1 is n really m difficult1 & z x seems c]ta9 t ?is new mat]ial w soon play a useful "p 9 *emical & physical rese>*1 ,i believe ! addition n[ made to ! e>li] book w add consid]ably to its value4 ,z glass is mu* less exp5sive to "w ) ?an silica1 ! beg9n] w f9d x be/ to sp5d a few days work+ ) ! common gas bl[-pipe & glass be=e he attempts to manipulate ! new & m refractory mat]ial4 ,!re=e1 9 writ+ ! new *apt]1 ,i h assum$ t ! read] is already m or less famili> ) ! re/ ( ! book1 & h giv5 only su* in/ructions & advice z w be requir$ by "o :o is already able to c>ry out simple "w at ! bl[-pipe4 ,w4 ,a4 ,,%5/one4 ,,clifton ,,college1 ,dec4 #aija4 ,,cont5ts ,,*apt] ,i4 ,,glass-,,bl[]',s ,,app>atus4 ,,page ,introductory--,! ,work+-place--,! ,bl[-pipe--,! ,bell[s--,automatic ,bl[]--,bl[-pipe ,flames1 #a-aa ,,*apt] ,,ii4 ,,v>ieties ,,( ,,glass ,,& ,,_! ,,managem5t4 ,*>act]s ( good ,glass--,clean+ & ,prep>+ a ,tube--,pres5t+ ,glass to ! ,flame--,me?ods ( work+ ) ,lead & ,s(t ,soda ,glass respectively--,managem5t ( ,soda ,glass--,anneal+--,! ,use ( ,combu/ion ,tube1 #ab-be ,,*apt] ,,iii4 ,,cutt+ ,,& ,,b5d+ ,,glass--,,=m+ ,,glass ,,app>atus ,,be=e ,,! ,,bl[-,,pipe--,,mak+ ,,& ,,gr9d+ ,,/opp]s ,,to ,,app>atus1 ,,etc4 ,cutt+ ,glass ,tubes--,b5d+ ,glass ,tubes--,r\nd+ & ,bord]+ ! ,ends ( ,tubes--,seal+--,*ok+1 or ,contract+ ! ,bore ( a ,glass ,tube--,wid5+ ,tubes--,pi]c+ ,tubes--,unit+ ,pieces ( ,glass to ,ea* ,o!r1 ,kn[n z ,weld+1 or ,sold]+--,bl[+ a ,bulb or ,globe ( ,glass--,mak+ & ,gr9d+ ,/opp]s1 #bf-ed ,,*apt] ,,iv4 ,,mak+ ,,?i/le ,,funnels1 ,u-,,tubes1 ,,etc4--,,comb9+ ,,! ,,p>ts ,,( ,,complicat$ ,,app>atus--,,m]cury1 ,,& ,,o!r ,,air-,,tight ,,jo9ts--,,vacuum ,,taps--,,safety ,,taps--,,air-,,traps4 ,electrodes--,u-,tubes--,spiral ,tubes--,?i/le ,funnels--,clos+ ,tubes conta9+ ,*emicals--,con/ruction ( ,app>atus ,consi/+ ( ,sev]al ,p>ts--,modes ( ,comb9+ ! ,p>ts ( ,heavy ,app>atus--,m]cury ,jo9ts--,vacuum ,taps--,lubricat+ ,taps--,air-,traps1 #ee-fi ,,*apt] ,v4 ,,graduat+ ,,& ,,calibrat+ ,,glass ,,app>atus4 ,to ,graduate ,tubes1 etc4--,to ,divide a ,giv5 ,l9e into ,equal ,p>ts--,to ,calibrate ,app>atus--,to ,calibrate ,tubes = ,measur+ ,gases--,to ,calibrate ! ,tube ( a ,!rmomet]1 #gj-ha ,,*apt] ,,vi4 ,,glass ,,tub+4 ,diagrams ( ,glass ,tubes1 %[+ ! *ief sizes 9 :i* !y are made1 #hb-hc ,,*apt] ,,vii4 ,,vitre\s ,,silica ,introductory--,prop]ties ( ,vitre\s ,silica--,prep>+ non-spl9t]+ ,silica f ,brazil ,pebble--,app>atus--,! ,me?od ( ,mak+ ,silica ,tubes--,precautions--,mak+ ,l>g] ,tubes & o!r ,app>atus ( ,silica--,qu>tz ,fibres1 #hd-ie ,,index1 #ig ,,*apt] ,i4 ,,glass-,,bl[]',s ,,app>atus4 ,introductory4--,i %all endeav\r to give su* an acc\nt ( ! op]ations requir$ 9 con/ruct+ glass app>atus z w be useful to *emical & o!r /ud5ts2 & z ?is book probably w come into ! h&s ( beg9n]s :o are n 9 a position to secure any fur!r assi/ance1 ,i %all include descriptions ev5 ( ! simple op]ations :i* are usually le>n$ dur+ ! fir/ few h\rs ( practical "w 9 a *emical or physical laboratory4 ,i %all n give any p>ticul> acc\nt ( ! manufacture ( su* app>atus z !rmomet]s1 taps1 etc41 because1 be+ 9 l>ge dem&1 !y c be b\ght s *eaply t "t is n pr(itably sp5t 9 mak+ !m4 ,b x w be f\nd t :at is includ$ w enable any "o1 :o w devote suffici5t "t to acquir+ ! necess>y manipulative dext]ity1 to prep>e su* app>atus z te/-tubes1 di/illation flasks1 app>atus = wa%+ gases1 ozone g5]at+ tubes1 etc41 :5 !y are requir$1 z !y (t5 are1 )\t delay or = special purposes4 ,! amateur probably w n succe$ 9 turn+ out app>atus s f9i%$ 9 appe>ance z t ( ! pr(essional glass-bl[] until aft] long practice1 b aft] a little daily practice = ! space ( a few weeks1 any "o :o is fairly skilful 9 ord9>y manipulation1 & :o p]sev]es 9 ! face ( failure at fir/1 w f9d himself able to make almo/ all ! app>atus he ne$s = lecture or o!r exp]im5ts1 ) a consid]able sav+ 9 laboratory exp5ses1 &1 :i* v (t5 is m important1 )\t ! delay t occurs :5 "o dep5ds ^u ! pr(essional glass-work]4 ,9 ! case ( ^? :o1 l myself1 "w 9 ! prov9ces1 ?is latt] advantage is a v weighty "o4 ,aft] ! description ( ! in/rum5ts us$ 9 glass-bl[+1 :i* imm$iately foll[s1 ! foll[+ arrangem5t ( ! subject has be5 adopt$4 ,9 ! fir/ place1 an acc\nt ( ! two *ief k9ds ( glass is giv51 & ( ! peculi>ities 9 ! behavi\r ( ea* ( !m be=e ! bl[-pipe1 :i* is foll[$ by a tol]ably m9ute description ( ! me?od ( p]=m+ ea* ( ! fundam5tal op]ations employ$ 9 fa%ion+ glass app>atus4 ,^! are n v num]\s1 & !y %\ld be ?or\ghly ma/]$ 9 succession1 pref]ably ^u tubes ( bo? soda & lead glass4 ,!n foll[s1 9 ,*apt] ,,iv41 an acc\nt ( ! application ( ^! op]ations to sett+ up complete app>atus1 full explanations ( ! con/ruction ( two or ?ree typical pieces ( app>atus be+ giv5 z examples1 & also descriptions ( ! modes ( mak+ v>i\s pieces ( app>atus :i* 9 ea* case pres5t "o or m special difficulties 9 _! con/ruction2 toge!r ) an acc\nt1 :i*1 ,i ?9k1 w be f\nd valuable1 ( "s app>atus t has be5 introduc$1 *iefly dur+ rec5t ye>s1 = exp]im5t+ ^u gases "u r$uc$ pressure1 e4g4 vacuum taps & jo9ts4 ,f9ally1 9 ,*apt] ,v41 !re is a %ort acc\nt ( ! me?ods ( graduat+ & calibrat+ glass app>atus = use 9 quantitative exp]im5ts4 ,! ,work+-place4--,! bl[-pipe mu/ be plac$ 9 a position p]fectly free f draughts4 ,x %\ld n face a w9d[1 nor be 9 too /rong a light1 if t c be avoid$1 = a /rong light w r5d] ! non-lum9\s flames1 :i* are us$ 9 glass-bl[+1 almo/ invisible1 & s]i\sly inconv5i5ce ! op]ator1 :o _c apply ! v>i\s p>ts ( ! flames to 8 glass ) ! degree ( c]ta9ty t is necess>y2 nei!r c he p]ceive ! condition ( ! glass s correctly 9 a /rong light1 = ?\gh 9 _m op]ations ! glass-work] is guid$ by feel+ r ?an by see+1 yet sight plays a v important "p 9 8 proce$+s4 ,my own bl[-pipe is plac$ ne> a w9d[ glaz$ ) opaque glass1 :i* looks s\?w>ds1 b is fac$ by build+s at a %ort di/ance4 ,9 dull wea!r ! light obta9$ is good2 b on mo/ days ,i f9d x advantage\s to %ade ! l[] half ( ! w9d[ ) a gre5 baize scre54 ,"s glass-bl[]s pref] gaslight to daylight4 ,! =m ( ! table us$ is unimportant1 provid$ t x is ( a conv5i5t height1 & all[s free play to ! foot :i* works ! bl[] und]nea? x4 ,! bl[] %\ld be fix$ 9 a conv5i5t position1 or x w get out ( control at critical mom5ts4 ,! table1 or t "p ( x :i* surr\nds ! bl[-pipe1 %\ld be cov]$ ) %eet-iron to protect x f ! action ( ! fragm5ts ( hot glass t w fall ^u x4 ,! tubes t supply air & gas to ! bl[-pipe %\ld come f b5ea? ! table1 & may pass ?r\gh holes cut = ! purpose4 ,_m glass-bl[]s pref] to "w at a r high table1 & sit on a r high /ool1 s t !y are well above _! "w4 ,no d\bt ?is gives extra comm& ov] ! "w 9 h&1 :i* is (t5 valuable4 ,on ! o!r h&1 x is some:at fatigu+4 ,= a long spell ( lab\r at "w :i* is n ( a novel "* nor specially difficult1 ,i am dispos$ to recomm5d sitt+ on a *air or l[ /ool1 at a table ( su* height z w enable ! elb[s to re/ easily ^u x :il/ ! glass is held 9 ! flame4 ,! precise heights t are desirable = ! table & /ool1 & ! exact position ( ! bl[-pipe1 w dep5d ^u ! height & l5g? ( arm ( ! individual workman1 & x mu/ !re=e be left to ea* p]son to select t :i* suits him be/4 ,a moveable re/ made ( wood1 = support+ ! remote end ( a long piece ( glass tube a few in*es above ! table1 :il/ ! o!r end is be+ heat$ 9 ! flame1 w be f\nd conv5i5t4 ,! ,bl[-pipe4--,=m]ly a lamp1 9 :i* sweet oil or tall[ 0 burnt1 0 employ$ = glass-work+1 & su* lamps are /ill occasionally us$4 ,?us1 lamps burn+ oil or tall[ 7 us$ on bo>d ! ,*all5g] = h]metically seal+ up flasks ( wat] collect$ at v>i\s dep?s to pres]ve !m = subsequ5t exam9ation4 ,i %all n1 h[ev]1 give an acc\nt ( su* a lamp1 = ! gas app>atus is s mu* m conv5i5t = mo/ purposes t x has n[ practically sup]s$$ ! oil lamps4 ,fig4 #a %[s a gas bl[-pipe ( exce$+ly simple con/ruction1 :i* c be easily made1 & ) :i* good "w c be done4 ,illu/ration3 ,,fig4 #a4 ,! tube ,a is ( brass1 & has a side tube ,b braz$ to x1 t5 to twelve c5timetres f ! end ,e1 accord+ to ! dim5sions ( ! tube4 ,a tube ( glass1 ,,ec1 is fitt$ into ,a by a cork at ,d4 ,b is connect$ to a supply ( gas by a flexible tube1 ,c is simil>ly connect$ to ! bl[]4 ,by means ( ,,ce a /ream ( air c be =c$ into gas burn+ at ! m\? ( ! bl[-pipe ,g1 & v>i\s flames1 ) ! *>act]s describ$ 9 a lat] section1 c be produc$ ) ?is in/rum5t4 ,= produc+ ! po9t$ flame 7,fig4 #c1 p4 #i7 ! op5+ ,e ( ! air-tube %\ld be contract$ to ! size ( a l>ge knitt+ ne$le4 ,= produc+ a flame ( l>ge size1 ri* 9 air 7,fig4 #d1 p4 #i71 ! int]nal diamet] ( ,e may be ne>ly half z great z t ( ,a )\t disadvantage4 ,?is bl[-pipe may be fix$ 9 position by ! spike ,f1 :i* w fit into holes 9 a block ( wood or a l>ge cork4 ,sev]al ( ^! holes 9 v>i\s positions %\ld be made 9 ! block1 s t ! position ( ! bl[-pipe may be v>i$ easily4 ,two taps mu/ be provid$ 9 conv5i5t positions ne> ! edge ( ! table to enable ! workman to regulate ! supplies ( air & gas4 ,^! taps %\ld be fix$ to ! table & be connect$ ) ! gas & air supplies respectively on "o side1 & ) ! bl[-pipe on ! o!r1 by flexible tubes4 ,if bl[-pipes ( ?is k9d be us$1 at lea/ two ( !m %\ld be provid$2 "o ( small dim5sions = work+ on small tubes & jo9ts1 ! o!r ( l>g] size = op]ations on l>g] tubes4 ,x w be conv5i5t to h bo? ( !m ready = use at all times1 z x is sometimes necess>y to employ l>ge & small flames on ! same piece ( "w 9 rapid succession4 ,by hav+ sev]al air-tubes ( diff]5t sizes fitt$ to ea* bl[-pipe1 a great] v>iety ( "w may be done4 ,= ! l>g] bl[-pipe1 ! int]nal diamet] ( ,a may be fifte5 to sev5te5 millimetres4 ,= ! small] in/rum5t1 elev5 millimetres = ! diamet] ( ,a w\ld be a useful size4 ,:5 a slightly great] outlay c be af=d$ x w be mo/ conv5i5t to pur*ase ! bl[-pipe4 ,!y c be obta9$ ( compact =m1 support$ on /&s ) univ]sal jo9ts giv+ great fre$om ( movem5t1 & ) taps = regulat+ ! supplies ( gas & air1 at comp>atively small co/4 ,z figures ( v>i\s bl[-pipes c be se5 9 ! price-li/s ( mo/ deal]s 9 app>atus1 !y are n giv5 "h4 ,_! introduction w\ld be ( b little s]vice1 = ! con/ruction ( t :i* is adopt$ c be readily asc]ta9$ by tak+ x to pieces4 ,! simple/ bl[-pipe usually us$ = glass-work+ is t ( ,h]apa?4 ,?is has two taps to regulate ! air & gas supplies respectively1 & w give a consid]able v>iety ( flames1 :i* w be discuss$ subsequ5tly4 ,an excell5t bl[-pipe1 made on ! same pr9ciple z t %[n 9 ,fig4 #a1 b m sub/antially & ) int]*angeable jets1 c be obta9$ f ,messrs4 ,mull] ( ,holborn = a mod]ate outlay4 ,ano!r v good bl[-pipe is ! ,automaton bl[-pipe ( ,mr4 ,flet*] ( ,w>r+ton4 ,9 ?is1 "o tap regulates ! supply bo? ( air & gas1 :i* is a great ga9 :5 difficult "w is 9 h&4 ,automaton bl[-pipes are made ( two sizes4 ,i h f\nd t ! l>g] size1 ) a p[]ful bell[s1 heats l>ge pieces ( lead glass v satisfactorily4 ,on ! o!r h&1 ! f9e-po9t$ oxidis+ flame ( ! ,h]apa? bl[-pipe is1 p]haps1 ! mo/ suitable = work+ jo9ts ( lead glass4 ,!re=e a good equipm5t w\ld be a small ,h]apa? bl[-pipe & a l>ge-siz$ ,automaton4 ,if only "o bl[-pipe is pur*as$ x %\ld be ei!r a m$ium-siz$ ,h]apa?1 or ! small] ,automaton1 z ^? are mo/ useful = g5]al "w4 ,mr4 ,flet*] also makes an +5i\s comb9ation ( two bl[-pipes 9 :i* ! gas & air supplies are regulat$ by a s+le lev]-h&le4 ,?is is v conv5i5t1 & gives flames t answ] well ) tubes made ( s(t soda glass1 & x is v useful = g5]al "w4 ,= use ) lead glass ! supply ( air is r too small1 & does n enable "o to get su* good results4 ,?is c be easily am5d$1 h[ev]4 ,by slightly increas+ ! size ( ! air-tube ( ! small] bl[-pipe1 & hav+ increas$ ! supply ( air to ! l>g] bl[-pipe also1 by r$uc+ ! ext]nal diamet] ( ! end ( ! inn]mo/ tube1 ,i n[ get m$ium-siz$ bru% flames & po9t$ flames ) ?is bl[-pipe1 t are equal to any ,i h us$ = heat+ lead glass4 ,= small laboratories ! inexp5sive ,no4 #e ,buns5 burn] ( ,mr4 ,flet*]1 :i* is conv]tible into a bl[-pipe1 w be v useful4 ,jets ( sev]al sizes to fit ! air-tubes ( bl[-pipes may be obta9$ ) !m1 & w s]ve = regulat+ ! supply ( air to ! flame4 ,! ,bell[s4--,! usual bl[+ app>atus is "s =m ( foot-bl[]4 ,^! may be obta9$ fitt$ to small tables ) %eet-iron tops4 ,b a mu* less exp5sive app>atus is ! l>ge foot-bl[] made by ,mr4 ,flet*] ( ,w>r+ton1 :i* c be us$ at an ord9>y table or laboratory b5*4 ,good foot-bl[]s c also be obta9$ f mak]s ( furnace bell[s4 ,no "p ( ! glass-bl[]'s equipm5t exce$s ! bell[s 9 importance4 ,! be/ bl[] procurable %\ld !re=e be adopt$4 ,a bell[s :i*1 :5 us$ ) a l>ge bl[-pipe1 w n enable y to heat l>ge pieces ( lead glass tube to r$ness )\t black5+ ! glass :5 ! directions = heat+ lead glass on pages #ag-ba are foll[$1 %\ld on no acc\nt be receiv$4 ,i am told t at "s places1 :]e ! wat]-supply is at v high pressure1 x is utilis$ = work+ bl[-pipes by means ( ! app>atus describ$ bel[1 & t "s glass-work]s f9d x advantage\s to use su* automatic bl[]s4 ,b aft] a little practice1 ! ef=t ( work+ ! bl[] ) ! foot :il/ manipulat+ ! glass is n a s\rce ( s]i\s inconv5i5ce4 ,inde$1 z x gives a c]ta9 degree ( control ov] ! flame )\t ! use ( ! h&s1 ! foot-bl[] is pref]able4 ,x is wor? :ile to describe an automatic bl[]1 h[ev]4 ,automatic ,bl[] 7,fig4 #b74--;,a /rong glass tube ,a is weld$ into a some:at l>g] tube ,b s t its end is ab\t #b mm4 f ! contraction at ,g4 ,b has a side tube ,c jo9$ to x4 ,! n>r[ end ( ,b is fix$ by an india-rubb] cork to a /rong bottle ,d ( two or ?ree litres capacity4 ,! india-rubb] cork also c>ries an exit tube ,e1 & ,d is pi]c$ ne> its bottom by a small hole at ,f4 ,illu/ration3 ,,fig4 #b ,9 us+ ! app>atus ,a is connect$ ) ! wat]-supply1 & wat] pass+ ?r\gh ,g1 c>ries air ) x into ,d4 ,! wat] escapes f ,d by ! op5+ at ,f1 & ! air is all[$ to pass out by ! tube ,e1 its passage be+ regulat$ by a tap4 ,fre% supplies ( air ent] ,b by ,c4 ,bl[-pipe ,flames--,! ,po9t$ ,flame4--,if ! gas tap ( a ,h]apa? bl[-pipe be adju/$ s t comp>atively little gas c pass1 & if ! foot-bl[] be !n work$ cauti\sly1 a long tongue ( flame end+ 9 a f9e po9t w be produc$ 7,fig4 #c74 ,?is flame w subsequ5tly be describ$ z ! po9t$ flame4 ,x %\ld be q free f lum9osity1 & z ! am\nt ( air necess>y = secur+ a po9t$ flame is l>ge1 9 proportion to ! gas1 !re is excess ( oxyg5 t[>ds ! end ,c4 ,by adju/+ ! proportions ( air & gas1 po9t$ flames ( v>i\s dim5sions c be obta9$ ) ! same bl[-pipe4 ,! "p ( a po9t$ flame to be us$ 9 glass-work+ is ! tip1 or 9 "s cases ! space slightly beyond ! tip4 ,illu/ration3 ,,fig4 #c4 ,illu/ration3 ,,fig4 #d4 ,! ,bru% ,flame4--,if a l>ge supply ( gas be turn$ on & a consid]able bla/ ( air s5t into ! flame1 a non-lum9\s flame ( great size w be obta9$ 7,fig4 #d74 ,9 =m x some:at resembles a l>ge camel's hair p5cil1 & may conv5i5tly be describ$ z a bru% flame4 ,! *ief advantage ( a l>ge-siz$ bl[-pipe is1 t ) x a l>ge bru% flame may be produc$1 :i* is (t5 invaluable4 ,by gradually dim9i%+ ! supply ( gas & air small] bru% flames may be produc$4 ,! jet us$ to supply air to ! ,h]apa? bl[-pipe is usually too f9e1 & consequ5tly does n p]mit ! passage ( suffici5t air to produce a bru% flame t conta9s excess ( oxyg51 ev5 ) ! aid ( a v p[]ful bl[]4 ,my own ,h]apa? bl[-pipe only gives a satisfactory oxidis+ bru% flame :5 ! jet is remov$ altoge!r f ! end ( ! air-tube4 ,= produc+ po9t$ flames ! f9] jet ( ! air-tube mu/ be us$1 b :5 a highly oxidis+ flame ( l>ge size is requir$ x mu/ be remov$4 ,! int]nal diamet] ( ! c5tral air-tube %\ld be ne>ly half z great z t ( ! out] or gas-supply tube4 ,flet*]'s ,automaton ) ! l>ge air jet gives a v lib]al supply ( air1 & produces an excell5t oxidis+ bru% flame4 ,9 ! case ( ! l>g]-siz$ ,automaton a consequ5ce ( ?is is1 h[ev]1 t :5 fitt$ ) ! l>ge jet x w n give s good a po9t$ flame z ! ,h]apa?1 :i*1 9 its turn1 gives an inf]ior oxidis+ bru%4 ,by fitt+ f9] jets to ! air-tube ( ,flet*]'s app>atus po9t$ flames c be secur$ :5 necess>y4 ,! ,smoky ,flame4--,by turn+ on a v free supply ( gas1 & only en\gh air to give an outw>d direction to ! burn+ gas1 a smoky flame1 *iefly useful = anneal+ & = "s simple op]ations on lead glass1 is produc$4 ,! ,gimm+ham bl[-pipe & ,flet*]'s comb9ation bl[-pipe1 9 addition to ! above flames1 are also adapt$ to produce a non-lum9\s flame1 resembl+ t ( ! ,buns5 gas-burn]1 :i* is v conv5i5t = ! prelim9>y heat+ ( ! glass1 & also = gradually cool+ f9i%$ app>atus4 ,x is n necess>y to describe ! me?od ( us+ ^! la/-m5tion$ bl[-pipes4 ,) ! m complicat$ ( !m directions = its use are suppli$4 ,mr4 ,madan has sugge/$ ! use ( oxyg5 9 place ( air = produc+ ! oxidis+ flame requir$ = work+ lead glass1 & to produce a flame ( high temp]ature = s(t5+ tubes ( h>d1 or combu/ion1 glass4 ,= ! latt] purpose ! employm5t ( oxyg5 may be adopt$ ) great advantage4 ,= work+ lead glass1 h[ev]1 x is q unnecess>y if ! directions already giv5 are foll[$4 ,! /ud5t's subsequ5t success w s l>gely dep5d ^u 8 acqua9tance ) ! res\rces ( 8 bl[-pipe1 & on ! facility ) :i* he c take advantage ( !m1 t no pa9s %\ld be sp>$ 9 ! ef=t to become exp]t 9 its managem5t z soon z possible4 ,a few exp]im5ts %\ld n[ be made1 !re=e1 ^u ! adju/m5t ( ! flame1 until ! /ud5t is able to produce & modify any =m ( flame ) promptness & c]ta9ty4 ,illu/ration3 ,,fig4 #e4 ,! rema9+ app>atus us$ 9 glass-work+ consi/s ( triangul> & o!r files1 *>coal pa/ils = cutt+ glass1 pieces ( s\nd *>coal ( v>i\s diamet]s ) conical ends2 x is conv5i5t to h "o end some:at less po9t$ ?an ! o!r 7,fig4 #e74 ,corks ( v>i\s sizes2 ! smalle/1 :i* are mo/ frequ5tly ne$$1 %\ld be c>efully cut ) %>p5$ cork bor]s f l>g] corks4 ,besides ^! !re %\ld be provid$ "s fre%ly di/ill$ turp5t9e 9 :i* camphor has be5 dissolv$1#a f9e & co>se em]y p[d]1 & "s %eets ( cotton-wadd+1 an india-rubb] bl[+-bottle1 glass tubes1 a little :ite enamel1 & a pair ( iron tongs4 #a ,half an ounce ( camphor to ab\t six ounces ( turp5t9e w d v well4 ,,*apt] ,,ii4 ,,v>ieties ,,( ,,glass ,,& ,,_! ,,managem5t4 ,all ! v>ieties ( glass t are ord9>ily met ) conta9 silica 7,si,o#b7 associat$ ) metallic oxides4 ,9 a true glass !re are at lea/ two metallic oxides4 ,! unmix$ silicates are n suitable = ! purposes ( glass4 ,!y are n s capable ( develop+ ! visc\s condition :5 heat$ z mixtures--"s ( !m are easily attack$ by wat]1 & _m ( ^? :i* are insoluble are comp>atively infusible4 ,!re is g5]ally excess ( silica 9 glass1 t is1 m ?an is necess>y to =m normal silicates ( ! metals pres5t4 ,! be/ proportions ( ! v>i\s con/itu5ts h be5 asc]ta9$ by glass-mak]s1 aft] long exp]i5ce2 b ! relation ( ^! proportions to ea* o!r1 f a *emical po9t ( view1 is n easy to make out4 ,! v>ieties ( glass f :i* tubes = *emical glass-bl[+ are made may be plac$ "u ?ree heads1 & are kn[n z#b-- ,s(t soda glass4 ,also kn[n z ,fr5* glass4 ,lead glass4 ,also kn[n z ,engli% glass4 ,h>d glass4 #b ,= details ( ! composition ( ! v>i\s glasses1 "s "w on glass-mak+ may be consult$4 ,9 pur*as+ glass tubes1 x is well to lay 9 a consid]able /ock ( tubes made ( ea* ( ! two fir/ v>ieties1 &1 if possible1 to obta9 !m f ! manufactur]1 = x frequ5tly happ5s t pieces ( glass f ! same bat* may be mu* m readily weld$ toge!r ?an pieces ( slightly diff]5t composition4 ,yet x is n well to lay 9 too l>ge a /ock1 z sometimes x is f\nd t glass det]iorates by prolong$ keep+4 ,z x is frequ5tly necess>y to make additions1 alt]ations1 or repairs to pur*as$ app>atus1 x is be/ to provide supplies bo? ( s(t soda glass & lead glass1 = ?\gh pur*as$ glass app>atus is frequ5tly made ( lead glass1 yet sometimes x is =m$ f ! soda glass1 & z x is a matt] ( "s difficulty to effect a p]man5t union betwe5 soda glass & lead glass1 x is desirable to be provid$ ) tubes ( bo? k9ds4 ,_m amateurs f9d t soda glass is 9 "s respects easi] to "w ) ?an lead glass4 ,b1 on ! o!r h&1 x is some:at m apt to crack dur+ cool+1 :i* causes mu* loss ( "t & disappo9tm5t4 ,also1 p]haps 9 consequ5ce ( its l[] conductivity = heat1 x v (t5 breaks "u sudd5 *anges ( temp]ature dur+ "w4 ,if1 h[ev]1 a supply ( good soda glass is obta9$1 & ! directions giv5 9 ?is book 9 reg>d to anneal+ x are ?or\ghly c>ri$ out1 ^! objections to ! use ( soda glass w1 to a great ext5t1 be remov$4 ,i f9d1 h[ev]1 t :5 e precaution has be5 tak51 app>atus made ( soda glass w be> v>iations ( temp]ature less well ?an t made ( lead glass4 ,!re=e1 al?\gh ! comp>atively inexp5sive soda glass may be employ$ = mo/ purposes )\t di/ru/1 yet ,i %\ld advise ^? :o propose to conf9e !mselves to "o k9d ( glass1 to take ! small extra tr\ble requir$ 9 le>n+ to "w lead glass4 ,9 ord] to secure glass ( good quality1 a few pieces %\ld be obta9$ z a sample1 & exam9$ by ! directions giv5 bel[4 ,:5 ! l>g] supply arrives1 a numb] ( pieces1 tak5 at r&om1 %\ld be exam9$ be=e ! bl[-pipe1 to comp>e _! behavi\r ) t ( ! sample pieces1 & ea* piece %\ld be sep>ately exam9$ 9 all o!r respects z describ$ subsequ5tly4 ,h>d glass is us$ = app>atus t is requir$ to )/& great heat4 ,x is difficult to s(t51 especially 9 l>ge pieces4 ,x %\ld only be employ$1 !re=e1 :5 ! l[ melt+ po9ts ( soda or lead glass w\ld r5d] !m unsuitable = ! purpose to :i* ! f9i%$ app>atus is to be put4 ,:at is sold z ,j5a combu/ion tube %\ld be pref]r$ :5 ?is is ! case4 ,*>act]s ( good ,glass4--,glass tubes = glass-bl[+ %\ld be z free z possible f knots1 air-bubbles1 & /ripes4 ,!y %\ld be 9 /raight pieces ( uni=m ?ickness1 & cyl9drical bore4 ,x is n possible to obta9 glass tubes ( absolutely ! same diamet] f "o end to ! o!r 9 l>ge quantities1 b ! v>iations %\ld n be consid]able4 ,:5 a %>p transv]se scrat* is made ) a good file on a piece ( tube1 & ! scrat* is t\*$ ) a r f9e po9t ( r$-hot glass 7?is %\ld be lead glass = a lead glass tube1 & soda glass = a tube ( soda glass71 ! crack :i* is />t$ %\ld pass r\nd ! glass1 s t x may be brok5 into two pieces ) regul> ends4 ,if ! crack proce$s v irregul>ly1 & especially if x t5ds to ext5d along ! tube1 ! glass has be5 badly anneal$1 & %\ld n be employ$ = glass-bl[+ purposes4 ,x is important t ! po9t ( hot glass us$ %all be v small1 h[ev]4 ,ev5 good glass w frequ5tly give an irregul> fracture if t\*$ ) a l>ge mass ( molt5 glass4 ,f9ally1 glass tube :i* is ?9 & ( small diamet] %\ld n crack :5 sudd5ly br\ght into a flame4 ,b l>g] & ?ick] tubes w n (t5 )/& ?is treatm5t4 ,!y %\ld n crack1 h[ev]1 :5 !y are br\ght into a flame gradually1 aft] hav+ be5 held 9 ! w>m air 9 front ( x = a m9ute or s4 ,good glass does n readily devitrify :5 held 9 ! bl[-pipe flame4 ,z devitrifi$ glass v (t5 may be re/or$ to its vitre\s condition by fusion1 devitrification mo/ frequ5tly %[s itself r\nd ! edges ( ! heat$ p>ts1 & may be recognis$ by ! production ( a c]ta9 degree ( r\ghness !re4 ,x is believ$ to be due to ! sep>ation ( c]ta9 silicates 9 ! cry/allis$ =m4 ,h>d glass1 :i* conta9s mu* calcium1 is m apt to devitrify ?an ! m fusible v>ieties4#c #c ,! pres5ce ( silicates ( calcium & alum9um are consid]$ to promote a t5d5cy to devitrification 9 glass2 & glasses ( complex composition are m apt to devitrify ?an ! simpl] v>ieties4 ,see ,glass-mak+1 by ,p[ell1 ,*ance1 & ,h>ris1 ,*ap4 ,,iv4 ,glass tubes are made ( v>i\s sizes4 ,:5 pur*as+ a supply1 x is necess>y to be some:at precise 9 indicat+ to ! v5dor ! sizes requir$4 ,i h !re=e plac$ at ! end ( ! book1 9 an app5dix1 a table ( numb]$ diagrams4 ,9 ord]+ tubes x w usually only be necess>y to give ! numb]s ( ! sizes wi%$ =1 & to specify ! quantity ( ea* size requir$4 ,9 ord]+ glass tubes by weight1 x mu/ be rememb]$ t a great _m l5g?s ( ! small] sizes1 b v few l5g?s ( ! l>g] sizes1 g to ! p\nd4 ,l>g]-siz$ tubes ?an ^? on ! diagram are also made4 ,9 ord]+ !m ! ext]nal diamet] & ?ickness ( glass pref]r$ %\ld be /at$4 ,clean+ & ,prep>+ a ,tube4--,x is frequ5tly mu* easi] to clean ! tube f :i* a piece ( app>atus is to be made ?an to clean ! f9i%$ app>atus4 ,a simple me?od ( clean+ a tube is to draw a piece ( wet rag :i* has be5 ti$ to a /r+ ?r\gh ! tube once or twice1 or1 ) small tubes1 to pu% a bit ( wet pap] or cotton wool ?r\gh !m4 ,if ! dirt _c be remov$ 9 ?is way1 ! int]ior ( ! tube %\ld be moi/5$ ) a little sulphuric acid 9 :i* "s bi*romate ( potassium has be5 dissolv$4 ,9 any case1 x mu/ f9ally be repeat$ly r9s$ ) di/ill$ wat]1 & dri$ by cauti\sly w>m+ x1 & suck+ or bl[+ air ?r\gh x4 ,9 ord] to avoid heat+ delicate app>atus :i* has become damp & ne$s dry+1 ! wat] may be wa%$ out ) a few drops ( _s1 :i* is readily remov$ at a l[ temp]ature4 ,be=e us+ a glass tube = an op]ation 9 :i* x w be necess>y to bl[ into x1 "o end ( x mu/ be contract$1 unless x is already ( su* a size t x c be held betwe5 ! lips ) p]fect ease2 9 any case1 its edges mu/ be r\nd$4 ,= descriptions ( ^! op]ations1 see page #ce4 ,! o!r end mu/ be clos$4 ,?is may be done by means ( a cork4 ,pres5t+ ,glass to ! ,flame4--,glass tubes mu/ nev] be br\ght sudd5ly into ! flame 9 :i* !y are to be heat$4 ,all glass is v likely to crack if s treat$4 ,x %\ld 9 all cases be held = a little :ile 9 front ( ! flame1 rotat$ con/antly 9 ! hot air & mov$ ab\t1 9 ord] t x may be w>m$ ov] a consid]able area4 ,:5 x has become pretty hot by ?is treatm5t1 x may be gradually br\ght ne>] to ! flame1 &1 f9ally1 into contact ) x1 /ill ) con/ant rotation & movem5t1 s z to w>m a consid]able "p ( ! tube4 ,:5 ! glass has be5 br\ght fairly into contact ) ! flame1 x w be safe to apply ! heat at ! requir$ "p only4 ,c>e mu/ be tak5 9 ^! prelim9>y op]ations to avoid heat+ ! m fusible glasses suffici5tly to s(t5 !m4 ,me?ods ( work+ ) ,lead & s(t ,soda ,glass respectively4--,:5 lead glass is heat$ 9 ! bru% flame ( ! ord9>y ,h]apa? bl[-pipe1 or )9 ! po9t ( ! po9t$ flame1 x becomes black5$ on its surface1 9 consequ5ce ( a portion ( ! lead becom+ r$uc$ to ! metallic /ate by ! r$uc+ gases 9 ! flame4 ,! same ?+ w happ5 9 b5d+ a lead glass tube if x is made too hot 9 a lum9\s flame4 ,a practical acqua9tance ) ?is ph5om5on may be acquir$ by ! foll[+ exp]im5t3-- ,take a piece ( lead glass tube1 br+ x gradually f ! po9t ( a po9t$ flame to a position well )9 ! flame1 & obs]ve :at happ5s4 ,:5 ! glass rea*es ! po9t ,a 7,fig4 #c71 or !reab\ts1 a d>k r$ spot w develop on ! glass1 ! area ( ! spot w increase z ! glass is br\ght fur!r 9 ! direction ,a to ,b4 ,if ! glass be !n remov$ f ! flame & exam9$1 x w be f\nd t a d>k metallic /a9 cov]s ! area ( ! d>k r$ spot previ\sly obs]v$4 ,repeat ! exp]im5t1 b at ! fir/ appe>ance ( ! d>k spot sl[ly move ! glass 9 ! direction ,a to ,c4 ,! spot w disappe>1 &1 if ! op]ation be prop]ly p]=m$1 9 its place !re w be a *>act]i/ically gre5i%-yell[ lum9\s spot ( highly heat$ glass4 ,9 ?is proce$+ ! r$uc$ lead ( ! d>k spot has be5 re-oxidis$ on pass+ into ! hot gases1 ri* 9 oxyg51 :i* ab\nd at ! po9t ( ! flame4 ,if "o end ( ! tube has be5 previ\sly clos$ by a piece ( cork1 & if air be =c$ into ! tube ) ! m\? f ! op5 end be=e ! lum9\s spot has become cool1 ! glass w exp&4 ,if ! exp]im5t be repeat$ sev]al times1 ) po9t$ flames ( v>i\s sizes1 ! op]ator w quickly le>n h[ to apply ! po9t$ flame to lead glass s t x may be heat$ )\t becom+ /a9$ ) r$uc$ lead4 ,if ! spot ( r$uc$ metal produc$ 9 ! fir/ exp]im5t be next br\ght into ! oxidis+ flame1 x also may gradually be remov$4 ,on occasion1 !re=e1 app>atus :i* has become /a9$ ) lead dur+ its production1 may be r5d]$ pres5table by suitable treatm5t 9 ! oxidis+ flame4 ,! process ( re-oxidis+ a consid]able surface 9 ?is way aft] x has cool$ d[n is apt to be v t$i\s1 h[ev]1 &1 especially 9 ! case ( ?9 tubes or bulbs1 (t5 is n practicable4 ,9 work+ ) lead glass1 !re=e1 any r$uction t occurs %\ld be remov$ by transf]r+ ! glass to ! oxidis+ flame at once4 ,small tubes1 & small areas on l>g] tubes ( ,engli% glass1 may be s(t5$ )\t r$uction by means ( ! po9t$ oxidis+ flame2 b x is n easy to heat any consid]able area ( glass suffici5tly ) a po9t$ flame4 ,& ?\gh x is possible1 ) c>e1 to employ ! hot space imm$iately 9 front ( ! visible end ( an ord9>y bru% flame1 :i* is ri* 9 air1 yet1 9 practice1 x w n be f\nd conv5i5t to heat l>ge masses ( lead glass nor tubes ( l>ge size1 to a suffici5tly high temp]ature to get ! glass into good condition = bl[+1 by pres5t+ !m to ! common bru% flame4 ,x may seem t z glass :i* has become /a9$ ) r$uc$ lead c be subsequ5tly re-oxidis$ by heat+ x ) ! tip ( ! po9t$ flame1 ! difficulty might be ov]come by heat+ x = work+ 9 ! bru% flame1 & subsequ5tly oxidis+ ! r$uc$ lead4 ,x is1 h[ev]1 difficult1 z previ\sly /at$1 to re-oxidise a l>ge surface ( glass :i* has be5 s]i\sly r$uc$ by ! action ( ! r$uc+ gases ( ! flame1 aft] x has cool$4 ,moreov]1 !re is ?is v s]i\s objection1 t if1 z may be necess>y1 ! action ( ! r$uc+ flame be prolong$1 ! ext5sive r$uction t takes place dim9i%es ! t5d5cy ( ! glass to acquire ! prop] degree ( viscosity = work+ x1 ! glass becomes difficult to exp& by bl[+1 s]i\sly r\gh5$ on its surface1 & (t5 assumes a v brittle or rott5 condition4 ,:5 x is only requir$ to b5d or draw out tubes ( lead glass1 !y may be s(t5$ suffici5tly by a smoky flame1 :i*1 probably ow+ to its hav+ a comp>atively l[ temp]ature1 does n s readily r$uce ! lead z flames ( high] temp]ature4 ,b = mak+ jo9ts1 collect+ masses ( glass = mak+ bulbs1 & 9 all cases :]e x is requir$ t ! glass %all be ?or\ghly s(t5$1 ! smoky flame does n give good results4 ,9 ! glass-works1 :]e l>ge quantities ( ornam5tal & o!r glass goods are made ( lead or fl9t glass1 ! pots 9 :i* ! glass is melt$ are s con/ruct$ t ! gases ( ! furnace d n come into contact ) ! glass2#d & z ! int5sely-heat$ sides ( ! melt+-pot ma9ta9 a v high temp]ature )9 x by radiation1 ! workman has a v conv5i5t s\rce ( heat to 8 h&1--he has1 9 fact1 only to introduce ! object1 or t "p ( x :i* is to be s(t5$1 into ! m\? ( ! melt+-pot1 & x is quickly heat$ suffici5tly = 8 purpose1 n only )\t contact ( r$uc+ gases1 b 9 air4 ,he c !re=e easily "w ^u v l>ge masses ( glass4 ,9 a special case1 su* a s\rce ( heat might be devis$ by ! amateur4 ,usually1 h[ev]1 ! difficulty may be ov]come )\t special app>atus4 ,x is1 9 fact1 only necess>y to c>ry out ! in/ructions giv5 bel[ to obta9 a consid]able bru% flame ri* 9 air1 9 :i* ! lead glass c be work$1 n only )\t discoloration1 b ) ! greate/ facility4 #d ,see ,pr9ciples ( ,glass-mak+1 p4 #ca4 ,to ,produce an ,oxidis+ ,bru% ,flame4--,! bl[] us$ mu/ be p[]ful1 ! air-tube ( ! bl[-pipe mu/ be ab\t half z great 9 diamet] z ! out] tube :i* supplies ! gas4 ,! op]ator mu/ "w 8 bell[s s z to supply a /rong & /eady bla/ ( air1 & ! supply ( gas mu/ be regulat$ s t ! bru% flame produc$ is free f e sign ( incomplete combu/ion1#e :i* may be kn[n by its out] zone be+ only fa9tly visible 9 daylight1 & q free f lum9\s /reaks 7see ,fig4 #d1 p4 #i74 ,:5 a suitable flame has be5 produc$1 try x by rotat+ a piece ( lead glass at or ne> ! end ( ! inn] blue "p ( ! flame 7,a ,fig4 #d72 ! appe>ance ( ! glass w quickly indicate r$uction4 ,:5 ?is occurs move ! glass =w>d to ! end ( ! out] zone ,b1 b keep x suffici5tly )9 ! flame to ma9ta9 x at a high temp]ature4 ,if all is "r ! metallic r$uction w quickly disappe>1 ! glass w become p]fectly transp>5t once m1 & w pres5t ! appe>ance previ\sly obs]v$ 9 ! exp]im5ts ) ! po9t$ flame1 or1 if v hot1 assume a br[ni%-r$ appe>ance4 ,if ?is does n occur1 ! supply ( air mu/ be increas$ or ! supply ( gas dim9i%$ until ! prop] effects are secur$4 #e ,nev]!less ! supply ( air mu/ n be s excessive z to r$uce ! temp]ature ( ! flame suffici5tly to prev5t ! ?or\gh s(t5+ ( ! glass1 :i* w occur if ! bell[s is work$ ) too mu* zeal4 ,9 work+ ^u lead glass ) ! highly oxidis+ bru% flame1 x is a good plan to heat x 9 ! r$uc+ "p ( ! flame ,a = ?or\ghly s(t5+ ! glass1 & to remove x to ! oxidis+ flame ,b to burn away ! r$uc$ metal4 ,9 prolong$ op]ations1 9 ord] t r$uction may nev] g too f>1 hold ! glass alt]nately 9 ! hot r$uc+ flame & 9 ! oxidis+ flame4 ,! inf]iority ( ! out] oxidis+ flame to ^? portions ne>] ! inn] blue zone = s(t5+ ! glass1 may p]haps be acc\nt$ = by ! pres5ce ( a l>g] proportion ( unconsum$ air 9 ! =m]1 :i* be+ heat$ at ! exp5se ( ! hot gases produc$ by combu/ion1 !reby l[]s ! temp]ature ( ! flame4 ,at or ne> ,a 7,fig4 #d7 :]e ! combu/ion is ne>ly complete1 b no excess ( air exi/s1 ! temp]ature w naturally be highe/4 ,if a v l>ge tube be rotat$ 9 ! oxidis+ flame at ,b 7,fig4 #d7 x may happ5 t ! flame is n l>ge en\gh to surr\nd ! tube1 & t z x is rotat$ ^? p>ts ( x :i* are mo/ remote f ! flame w cool d[n too consid]ably to all[ all p>ts ( ! tube to be simultane\sly br\ght into ! desir$ condition4 ,?is difficulty may be ov]come by plac+ two bl[-pipes exactly opposite to ea* o!r1 at su* a di/ance t !re is an int]val ( ab\t an in* betwe5 ! extremities ( _! flames1 & rotat+ ! tube betwe5 ! two flames4 ,x may be necess>y to provide two bl[]s = ! bl[-pipes if !y are l>ge4 ,aga91 if a v n>r[ zone ( a tube ( mod]ate size is to be heat$1 two po9t$ flames may be simil>ly arrang$ ) advantage4 ,occasionally m ?an two flames are made to conv]ge ^u "o tube 9 ?is mann]4 ,ano!r me?od ( prev5t+ "o side ( a tube f cool+ d[n :il/ ! o!r is pres5t$ to ! flame1 is to place a brick at a %ort di/ance f ! extremity ( ! flame4 ,! brick *ecks ! loss ( heat consid]ably4 ,a block ( bee* wood may be us$ = ! same purpose1 ! wood ignites & !reby itself becomes a s\rce ( heat1 & is ev5 m effective ?an a brick4 ,full] details ( ! managem5t ( lead glass "u v>i\s circum/ances w be f\nd 9 ! subsequ5t descriptions ( op]ations be=e ! bl[-pipe4 ,be=e proce$+ to "w ) soda glass1 ! /ud5t %\ld n only v]ify by exp]im5ts :at has be5 already said1 b he %\ld famili>ise himself ) ! action ( ! bl[-pipe flame on lead glass by try+ ! glass 9 e "p ( ! flame1 v>y+ ! proportions ( gas & air 9 e way1 repeat+1 & repeat+1 8 exp]im5ts until he c obta9 any desir$ effect ) c]ta9ty & promptitude4 ,he %\ld practice "s ( ! simpl] op]ations giv5 9 ,*apt] ,,iii4 9 ord] to impress :at he has le>n$ well on 8 m9d4 ,managem5t ( ,soda ,glass4--,9 work+ ) soda glass ! foll[+ po9ts mu/ be con/antly kept 9 m9d4 ,t z x is mu* m apt ?an lead glass to crack :5 sudd5ly heat$1 great caution mu/ be ex]cis$ 9 br++ x into ! flame2 & t 9 mak+ l>ge jo9ts or 9 mak+ two jo9ts ne> ea* o!r1 all p>ts ( ! tube adjac5t to t :i*1 = ! mom5t1 is be+ heat$1 mu/ be kept hot1 z x is v apt to crack :5 adjac5t p>ts are unequally heat$4 ,?is may be effect$ by /opp+ "w at %ort int]vals & w>m+ ! cool] p>ts ( ! tube1 or by ! use ( ! brick or block ( wood to *eck radiation1 or ev5 by plac+ a supplem5t>y bl[-pipe or ,buns5 burn] 9 su* a position t its flame plays ^u ! m di/ant p>ts ( ! "w1 n com+ suffici5tly into contact to s(t5 ! glass1 h[ev]1 b ne> en\gh to keep x well heat$4 ,la/ly1 to prev5t ! f9i%$ "w f fall+ to pieces aft] or dur+ cool+1 ! directions giv5 "u ! head ( anneal+ mu/ be c>efully c>ri$ out4 ,9 v mu* ( 8 "w ! glass-bl[] is guid$ m by ! feel ( ! glass ?an by :at he sees4 ,! p[] ( feel+ glass c only be acquir$ by practice1 & aft] a c]ta9 am\nt ( prelim9>y failure4 ,z a rule ,i h obs]v$ t beg9n]s are apt to raise _! glass to a high] temp]ature ?an is necess>y1 & t !y employ l>g] flames ?an are want$4 ,if glass be made too s(t x may fall s completely out ( %ape z to become unworkable except 9 v skilful h&s4 ,! foll[+ rules1 !re=e1 %\ld be /rictly adh]$ to4 ,always employ 9 ! fir/ in/ance ! smalle/ flame t is likely to d ! "w requir$4 ,9 op]ations involv+ bl[+ out visc\s glass1 attempt to bl[ ! glass at l[ temp]atures be=e high] ones are tri$4 ,aft] a little exp]i5ce ! adoption ( ! "r-siz$ flame = a giv5 purpose1 & ! p]ception ( ! be/ condition ( glass = bl[+ x1 become almo/ automatic4 ,i may add t glass :i* is to be b5t ne$s to be mu* less heat$ ?an glass :i* is to be bl[n4 ,anneal+4--,if app>atus1 ! glass ( :i* is v ?9 & ( uni=m sub/ance1 be heat$1 on removal f ! s\rce ( heat x w cool equally ?r\gh\t1 & !re=e may (t5 be heat$ & cool$ )\t any special precautions4 ,if ! glass be ?ick1 & especially if x be ( unequal ?ickness 9 v>i\s p>ts1 ! ?9n] portions w cool m quickly ?an ^? :i* are m massive2 ?is w result 9 ! production ( t5sion betwe5 ! ?ick] & ?9n] p>ts 9 consequ5ce ( inequality 9 ! rates ( contraction1 & fractures w occur ei!r spontane\sly or ^u any sudd5 %ock4 ,?us1 if a hot tube be t\*$ ) cold or wet iron1 or slightly scrat*$ ) a cold file1 ! inequality ( ! rate ( cool+ is great1 & x breaks at once4 ,x is !re=e necess>y to secure t hot glass %all cool z regul>ly z possible4 ,& ?is is p>ticul>ly important 9 ! case ( articles made ( soda glass4 ,"s glass-bl[]s cont5t !mselves ) p]mitt+ ! glass to cool gradually 9 a smoky flame till x is cov]$ ) c>bon1 & !n leave x to cool ^u ! table4 ,b "u ?is treatm5t _m jo9ts made ( soda glass :i* are n q uni=m 9 sub/ance1 b o!rwise s]viceable1 w break d[n4 ,9 glass-works ! anneal+ is done 9 ov5s s arrang$ t ! glass ent]s at ! hotte/ end ( ! ov5 :]e x is uni=mly heat$ to a temp]ature n mu* bel[ t at :i* x becomes visc\s1 & sl[ly pass$ ?r\gh ! cool] p>ts ( ! *amb] s t x em]ges cold at ! o!r end4 ,?is me?od ( anneal+ is n practicable 9 a small laboratory4 ,b =tunately v good results c be obta9$ by ! foll[+ simple device1 viz43-- ,by wrapp+ ! hot app>atus t is to be anneal$ closely 9 cotton wool1 & leav+ x !re till q cold4 ,! glass %\ld be wrapp$ up imm$iately aft] x is bl[n into its f9al %ape1 z soon z x is no long] s(t en\gh to give way "u slight pressure4 ,& x %\ld be heat$ z uni=mly z possible1 n only at ! jo9t1 b also ab\t ! p>ts adjac5t to ! jo9t1 at ! mom5t ( surr\nd+ x ) ! cotton4 ,lead glass appe>s to cool m regul>ly ?an soda glass1 & ^! precautions may be m safely neglect$ ) app>atus made ( lead glass2 b n always4 ,at ! date ( writ+ ,i h _h sev]al well-bl[n jo9ts ( ?ick-wall$ capill>y tube to ,no4 #af 7see diagram1 p4 #hb71 break dur+ cool+1 9 consequ5ce ( circum/ances mak+ x dang]\s to heat ! neighb\rhood ( ! jo9t s mu* z 0 necess>y4 ,! black c>bonace\s coat =m$ on hot glass :5 x is plac$ 9 cotton wool may be remov$ by wip+ ) me?ylat$ _s1 or1 if x be v closely adh]5t1 by g5tly rubb+ ) f9e em]y1 moi/5$ ) ! _s4 ,cotton wool is r dang]\sly inflammable2 x %\ld !re=e be kept out ( rea* ( ! bl[-pipe flame1 & c>e %\ld be tak5 t ! glass is n plac$ 9 contact ) x at a suffici5tly high temp]ature to cause its ignition4 ,ano!r me?od ( anneal+ is to cov] ! hot glass ) hot s&1 & all[ x to cool !re94 ,z 9 ! case ( lead glass1 s ) soda glass4 ,a ?or\gh acqua9tance ) ! effect ( ! v>i\s p>ts ( ! flame ^u x %\ld be ga9$ be=e fur!r "w is ent]$ ^u1 = :i* purpose an h\r or m sp5t 9 obs]v+ its behavi\r 9 ! flame w be fully repaid by increas$ success subsequ5tly4 ,! ,use ( ,combu/ion ,tube4--,x is (t5 necess>y to con/ruct app>atus ( :at is kn[n z h>d glass or combu/ion tube4 ,x is almo/ z easy to "w combu/ion tube z to deal ) lead & soda glass if ! oxy-hydrog5 flame be employ$4 ,x is n necess>y to set up a special app>atus = ?is purpose2 _m ( ! ord9>y bl[-pipes c be us$ ) oxyg5 in/ead ( ) air4 ,x is only necess>y to connect ! air-tube ( ! bl[-pipe ) a bottle ( compress$ oxyg5 in/ead ( ) ! bell[s4 ,! connect+ tube %\ld n be too wide nor too long1 9 ord] to avoid ! accumulation 9 x1 by accid5t1 ( l>ge quantities ( explosive mixtures4 ,two precautions are necess>y 9 manipulat+ h>d glass 9 ! oxy-hydrog5 flame4 ,! glass mu/ n be ov]heat$4 ,at fir/ "o is v apt to g wrong 9 ?is direction4 ,! supply ( oxyg5 mu/ n be too great2 a small hiss+ flame is n :at is want$4 ,if ei!r ( ^! precautions are neglect$ mo/ glass w devitrify badly4 ,) a little c>e & exp]i5ce1 devitrification c be absolutely avoid$4 ,ord9>y combu/ion tube c be us$1 b ,i f9d t ! glass tube 7,v]br5nungsroehr7 made by ,s*ott ,co4 ( ,j5a1 :i* c be obta9$ ?r\gh any firm ( deal]s 9 app>atus1 is f> bett] ?an ! ord9>y tube4 ,by foll[+ ^! in/ructions1 any "o :o has le>n$ h[ to "w ) lead or soda glass w f9d x easy to manipulate h>d glass4 ,,*apt] ,,iii4 ,,cutt+ ,,& ,,b5d+ ,,glass--,,=m+ ,,glass ,,app>atus ,,be=e ,,! ,,bl[-,,pipe--,,mak+ ,,& ,,gr9d+ ,,/opp]s ,,to ,,app>atus1 ,,etc4 ,9 ! lat] pages ( ?is ,*apt] x w be assum$ t ! op]ations fir/ describ$ h be5 ma/]$4 ,! beg9n] %\ld !re=e practise ea* op]ation until he f9ds himself able to p]=m x ) "s degree ( c]ta9ty4 ,g5]ally speak+1 h[ev]1 aft] ! failure ( two or ?ree attempts to p]=m any op]ation1 x is be/ to give up = a few h\rs1 & proce$ to ! "w next describ$1 return+ to t ^u :i* y h fail$ subsequ5tly4 ,if1 un=tunately1 x %\ld happ5 t ! "w next 9 ord] involves ! p]=mance ( ! op]ation 9 :i* ! failure has occurr$1 x is be/ to pass on to "s lat] "w :i* does n dem& ?is p>ticul> accompli%m5t1 or to re/ a :ile1 & re-attack ! difficulty :5 refre%$4 ,cutt+ ,glass ,tubes4--,! simple/ me?od ( cutt+ a glass tube is to make a %>p scrat* ) a file across ! glass at ! po9t :]e x is desir$ to cut x1 & on pull+ ap>t ! two ends1 x w break clean (f4 ,x is important t ! file be %>p4 ,9 pull+ ap>t ! ends ! scrat* %\ld be held upw>ds1 & ! pull %\ld h a d[nw>d direction1 :i* w t5d to op5 out ! scrat*4 ,9 ! case ( a l>ge tube1 a scrat* w n ensure its break+ clean across4 ,! tube mu/ be fil$ to "s dep?1 half-way1 or ev5 all r\nd x4 ,a good way ( break+ a tube is to place ! file 9 ! table aft] scrat*+ ! glass1 to hold ! glass tube above its edge ) "o h& on ea* side ( ! scrat*1 & to /rike ! "u side ( ! tube a %>p bl[ ^u ! edge ( ! file1 directly b5ea? ! scrat*4 ,9 ?is way v ev5 fractures ( l>ge & mod]ately ?9 tubes may be made4 ,x answ]s p>ticul>ly well = remov+ %ort ends ( tube1 n long en\gh to hold2 ! tube is held firmly ^u ! file1 & a %>p bl[ giv5 to ! %ort end ) a piece ( l>ge tube or a key4 ,a file ^: faces h be5 gr\nd till !y are ne>ly smoo?1 s z to leave v f9ely-s]rat$ edges1 w be f\nd useful = cutt+ glass tubes4 ,su* a file %\ld be us$ almo/ z a knife is us$ = cutt+ a p5cil 9 halves4 ,! simple me?ods j describ$ are too viol5t to be appli$ to delicate app>atus1 too t$i\s :5 employ$ ^u ! l>ge/ tubes1 & v difficult to apply :5 ! tube to be cut is v ?91 or too %ort to p]mit ! op]ator to get a good grip ( x on ei!r side ( ! file m>k4 ,9 su* cases1 "o or o!r ( ! foll[+ me?ods w be useful3-- #a4 ,make a scrat* ) a file1 & t\* x ) ! end ( a v small piece ( glass drawn out & heat$ at ! tip to its melt+ po9t4 ,x is important t ! heat$ po9t ( glass be v small1 or ! fracture is likely to be unev51 or to spread 9 sev]al directions4 ,also1 x is be/ to use hot soda glass = />t+ cracks 9 tubes ( soda glass1 & lead glass = do+ s 9 lead glass tubes4 ,if ! crack does n pass q r\nd ! tube1 y may pull x asund]1 z previ\sly describ$1 or y may br+ ! heat$ piece ( glass ) :i* ! crack 0 />t$ to "o end ( ! crack1 & sl[ly move x 7ne>ly t\*+ ! glass7 9 ! requir$ direction2 ! crack w ext5d1 foll[+ ! movem5ts ( ! hot glass4 ,in/ead ( hot glass1 pa/ils ( *>coal are sometimes employ$ = ?is purpose4 ,!y cont9ue to burn :5 once light$1 & !re is no ne$ to re-heat !m f "t to "t4 ,!y %\ld be br\ght z close to ! glass z is possible )\t t\*+ x1 &1 :5 no long] ne$$1 %\ld be ext+ui%$ by plac+ ! light$ end "u s&1 or "s o!r incombu/ible p[d]1 = !y mu/ n be wett$4 #b4 ,a me?od mu* practis$ by ! mak]s ( %eet glass1 & suitable = l>ge objects1 is to wrap a ?read ( hot glass r\nd ! tube1 at once remov+ x1 & t\*+ any po9t ( ! glass :i* ! ?read cov]$ ) wat] or a cold iron1 :5 a crack w be />t$ & w pass r\nd ! glass :]e x 0 heat$ by ! ?read4 #c4 ,tubes :i* are l>ge & slightly conical may h a r+ ( r$-hot iron pass$ ov] !m till x comes into contact ) ! glass1 !n1 ! iron be+ remov$1 & a po9t on ! heat$ glass be+ at once t\*$ ) cold iron z be=e1 x w break z desir$4 ,or a /r+1 moi/5$ ) turp5t9e1 may be loosely twi/$ r\nd ! tube1 & ! turp5t9e ignit$1 aft]w>ds ! application ( sudd5 cold to any po9t on ! zone ( hot glass w usually />t a crack1 :i*1 if necess>y1 may be cont9u$ 9 ! usual mann]4 ,! la/ ?ree me?ods are *iefly useful 9 deal+ ) ! l>ge/ & ?icke/ tubes1 & ) bottles4 ,a fairly /\t copp] wire1 b5t into ! =m ( a b[ s t x c be appli$ :5 hot to a consid]able surface ( a glass tube1 w be f\nd sup]ior to ! po9t ( hot glass or metal usually employ$1 = lead+ cracks 9 glass tubes4 ,) su* a wire a tube c be cut s t ! cross section ( ! end is at any desir$ angle to ! axis ( ! tube1 ) consid]able precision4 ,i am indebt$ = ?is sugge/ion to ,mr4 ,v]non ,boys & ,dr4 ,eb]t4 ,b5d+ ,glass ,tubes4--,! bl[-pipe flame is n a suitable s\rce ( heat = b5d+ tubes1 except 9 c]ta9 cases :i* w be m5tion$ 9 a subsequ5t p>agraph4 ,= small tubes1 & ^? ( mod]ate size1 a fi%-tail burn]1 su* z is us$ = purposes ( illum9ation1 w answ] be/4 ,use a flame f "o to two in*es 9 bread?--f ,a to ,a 7,fig4 #f71 accord+ to ! size ( ! tube :i* is to be b5t4 ,if ! l5g? ( tube t is heat$ be less ?an ?is1 ! b5d w probably buckle on its concave side4 ,illu/ration3 ,,fig4 #f4 ,! tube to be heat$ %\ld be held 9 ! position %[n 9 ,fig4 #f1 support$ by ! h&s on ea* side4 ,x %\ld be con/antly rotat$ 9 ! flame1 t x may be equally heat$ on all sides4 ,9 ! figure ! h&s are repres5t$ above ! tube1 ) _! backs upw>ds4 ,a tube c be held equally well f bel[1 ! backs ( ! h&s be+ !n direct$ d[nw>ds1 & ?is1 ,i ?9k1 is ! m frequ5t habit4 ,x is difficult to say :i* position ( ! h&s is to be pref]r$4 ,i lately obs]v$ h[ a tube 0 held by ?ree skilful amateurs & by a pr(essional glass-bl[]4 ,all ! =m] held ! tube ) ! h&s bel[ x4 ,! latt]1 h[ev]1 held x f above1 z 9 ,fig4 #f4 ,he1 h[ev]1 0 work+ ) a r heavy piece ( tube1 & ,i am incl9$ myself to recomm5d t position 9 su* cases4 ,dur+ a long spell ( "w1 ! wri/ may be re/$ f "t to "t by *ang+ ! position ( ! h&s4 ,:5 ! tube has s(t5$1 remove x f ! flame1 & g5tly b5d x to ! desir$ angle4 ,! side ( ! tube la/ expos$ to ! flame w be slightly hott]1 & !re=e s(t]1 ?an t :i* is opposite to x4 ,?is hott] side %\ld =m ! concave side ( ! b5t tube4 ,illu/ration3 ,,fig4 #g4 ,! exact condition 9 :i* ! glass is mo/ suitable = b5d+ c only be le>n$ by mak+ a few trials4 ,if x is too s(t 9 consequ5ce ( be+ ov]heat$1 ! sides w collapse4 ,if1 9 ! endeav\r to heat ! side ,a ( ,fig4 #g a little m ?an ,b1 ,b is insuffici5tly heat$1 ! tube w be likely to break on ! convex side ,b4 ,if ! b5t tube be likely to become flatt5$1 & ?is _c always be prev5t$ 9 b5d+ v ?9 tubes1 ! fault may be avoid$ by bl[+ g5tly into "o end ( ! tube :il/ b5d+ x1 = :i* purpose ! o!r end %\ld be clos$ be=eh&4 ,a tube already flatt5$ may1 to "s ext5t1 be bl[n into %ape aft] clos+ "o end & re-heat+ ! b5t portion1 b x is n easy to give x a really good %ape4 ,:5 mak+ a b5d l t 9 ,fig4 #g1 to secure t ! arms ( ! tube ,c & ,d1 & ! curve at ,b1 %all be 9 "o plane1 ! tube %\ld be held 9 a position p]p5dicul> to ! body1 & br\ght into ! position %[n 9 ! figure dur+ b5d+1 by :i* means x w be f\nd easy to secure a good result4 ,lead glass tubes mu/ be remov$ f ! flame be=e !y become hot en\gh to und]go r$uction4 ,if !y %\ld become black5$1 h[ev]1 ! /a9 may be remov$ by re-heat+ 9 ! oxidis+ flame 7see p4 #ah74 ,:5 a v %>p b5d is to be made1 x is sometimes be/ to heat a n>r[ zone ( ! glass r highly 9 ! bl[-pipe flame1 & to bl[ ! b5d into %ape at ! mom5t ( b5d+ x1 z previ\sly describ$1 "o end hav+ be5 clos$ = t purpose be=eh&4 ,lead glass %\ld be heat$ = ?is purpose 9 ! oxidis+ flame 7pp4 #ag to #bb74 ,! processes ( b5d+ l>ge tubes1 mak+ ,u-tubes & spiral tubes1 are m difficult op]ations1 & w be expla9$ 9 ,*ap4 ,,iv4 ,r\nd+ & ,bord]+ ! ,ends ( ,tubes4--,aft] cutt+ a piece ( glass tube 9 two pieces1 ! %>p edges left at its ends %\ld be r\nd$ by hold+ !m 9 a flame = a few mom5ts till ! glass beg9s to melt4 ,! oxidis+ po9t ( a po9t$ flame may be us$ = bo? k9ds ( glass4 ,! flame w be col\r$ yell[ by soda glass at ! mom5t ( melt+4 ,?is indication ( ! condition ( soda glass %\ld be not$1 = x s]ves z a crit]ion ( ! condition ( ! glass4 ,! ends ( soda glass tubes may also be r\nd$ 9 ! flame ( a common ,buns5's burn]4 ,:5 ! end ( a tube is to be clos$ ) a cork or /opp]1 its m\? %\ld be exp&$ a little1 or bord]$4 ,to d ?is1 heat ! end ( ! tube by rotat+ x 9 ! flame till x s(t5s1 !n remove x f ! flame1 at once introduce ! *>coal cone 7,fig4 #e1 p4 #aa71 & rotate x ) g5tle pressure aga9/ ! s(t5$ glass till ! desir$ effect is produc$4 ,9 do+ ?is x is v important t ! end ( ! tube %all be uni=mly heat$1 9 ord] t ! enl>gem5t %all be ( regul> =m4 ,if ! tube _c be suffici5tly exp&$ at "o op]ation1 x %\ld be re-heat$ & ! process repeat$4 ,bord]s1 su* z are se5 on te/-tubes1 are made by press+ ! s(t5$ edge ( ! tube aga9/ a small iron rod4 ,! end ( ! rod %\ld project ov] ! s(t5$ edge ( ! tube at a slight angle1 & be press$ aga9/ x1 pass+ ! rod r\nd ! tube1 or rotat+ ! tube "u ! rod4 ,seal+1 t is clos+ ! ends ( tubes1 or o!r op5+s1 9 glass app>atus4 ,9 p]=m+ ?is & all ! o!r op]ations ( glass bl[+1 ! foll[+ po9ts mu/ be con/antly kept 9 m9d3-- 7a47 ,t x is r>ely safe to bl[ glass :il/ x is /ill 9 ! flame1 except 9 c]ta9 special cases t w be m5tion$ subsequ5tly4 ,!re=e always remove app>atus f ! flame be=e bl[+4 7b47 ,t :5 heat+ glass tubes1 unless x is specially desir$ to heat "o portion only1 ! tube mu/ be con/antly rotat$ 9 ! flame to ensure t x %all be uni=mly heat$1 & to prev5t ! tube or mass ( glass f assum+ an irregul> =m4 7c47 ,always bl[ g5tly at fir/1 & sl[ly increase ! =ce appli$ till y feel or see ! glass giv+ way4 ,x is a good plan to =ce ! air =w>d 9 successive %ort bla/s r ?an 9 "o cont9u$ /ream4 7d47 ,:5 x is necess>y to =ce air into tubes ( f9e bore1 su* z !rmomet] tubes1 ! m\? mu/ n be us$1 = moi/ure is !reby introduc$ into ! tube1 :i* x is v difficult to remove aga9 9 _m cases4 ,all tubes ( v small bore %\ld be bl[n ) ! aid ( an india-rubb] bl[+-bottle1 su* z are us$ = spray-produc]s1 ,galton's :i/les1 etc4 ,! tube to be bl[n mu/ be securely fix$ to ! neck ( ! bottle1 :i* is !n held 9 "o h&1 & air is =c$ f x into ! tube z x is requir$4 ,^! bottles are frequ5tly ( s]vice to ! glass-bl[]--e4g41 :5 tubes ( v f9e bore h to be unit$1 x is necess>y to ma9ta9 an int]nal pressure slightly exce$+ t ( ! air ?r\gh\t ! op]ation1 9 ord] to prev5t ! visc\s glass f runn+ toge!r & clos+ ! tube4 ,an india-rubb] bl[+-ball is v conv5i5t = ?is purpose4 ,to seal ! end ( a glass tube 7,fig4 #h71 adju/ ! flame s t x w heat a zone ( glass ab\t z broad z ! diamet] ( ! tube to be seal$ 7see ,a1 ,fig4 #h74 ,hold ! tube on ea* side ( ! po9t :]e x is to be seal$ 9 ! mann] describ$ 9 ! description ( b5d+ glass tubes 7p4 #bh74 ,br+ ! tube gradually into ! flame1 & heat x ) con/ant rotation1 till ! glass s(t5s 7= lead glass ! oxidis+ flame mu/ be us$1 z has be5 already expla9$74#f ,:5 ! glass beg9s to ?ick51 g5tly pull asund] ! two ends1 tak+ c>e n to pull out ! s(t5$ glass too mu*1 b to all[ ! sides to fall toge!r1 z %[n at ,a4 ,:5 ?is has occurr$1 heat ! glass at ! n>r[ "p till x melts1 & pull asund] ! two ends4 ,! clos$ end %\ld pres5t ! appe>ance %[n at ,d4 ,if ! glass be drawn out too quickly its ?ickness w be unduly r$uc$1 & x w pres5t ! appe>ance %[n at ,b4 ,9 t case apply a po9t$ flame at b1 & repeat ! previ\s op]ation s z to contract ! tube z at c1 tak+ c>e n to all[ ! glass to become mu* increas$ nor decreas$ 9 ?ickness4 #f ,rememb] t :5 ! lead glass is heat$ to ! prop] temp]ature x w pres5t an appe>ance :i* may be describ$ z a gre5i% phosphoresc5ce4 ,at high] temp]atures x assumes an orange-r$ appe>ance4 ,if x loses its transp>5cy & assumes a dull appe>ance1 x mu/ be mov$ fur!r into ! oxidis+ p>ts ( ! flame4 ,if a consid]able mass ( glass be left at d1 x may be remov$ by heat+ x to r$ness1 t\*+ x ) ! po9t$ end ( a cold glass tube1 to :i* x w adh]e1 & by :i* x may be pull$ away4 ,illu/ration3 ,,fig4 #h4 ,:5 ! end ( ! tube pres5ts ! appe>ance %[n 9 ! diagram ,d1 & ! mass ( glass at d is small1 ! small lump t rema9s mu/ be remov$ by heat+ x till x s(t5s1 & g5tly bl[+ ) ! m\?1 s z to r\nd ! end & di/ribute ! glass m regul>ly1 z %[n 9 ,e4 ,! :ole end1 f ! dott$ l9e e1 mu/ !n be heat$ ) con/ant rotation 9 ! flame4 ,if ?is f9al heat+ ( ! end e be done skilfully1 ! glass w probably collapse & flatt51 z at ,f4 ,! end mu/ !n be g5tly bl[n into ! =m %[n at ,g4 ,if a flat end to ! tube be desir$1 ! tube may be left 9 ! condition %[n by ,f1 or a ?9 r\nd$ end may be flatt5$ by pressure on a plate ( iron4 ,if a concave end be wi%$ =1 x is only necess>y to g5tly suck air f ! tube be=e ! flatt5$ end has become solid4 ,9 ea* case1 imm$iately aft] ! tube is complet$1 x mu/ be closely wrapp$ 9 cotton wool & left to cool4 ,) good lead glass ?is la/ process1 ?\gh advantage\s1 is n absolutely necess>y2 & z glass cools sl[ly :5 envelop$ 9 cotton wool1 ?is precaution may frequ5tly be neglect$ 9 ! case ( app>atus made f lead glass4 ,illu/ration3 ,,fig4 #i4 ,9 ord] to draw out tubes = seal+1 close to "o end1 & ?us to avoid wa/e ( mat]ial1 x is a good plan to heat simultane\sly ! end ( ! glass tube ,a :i* is to be seal$1 & "o end ( a piece ( wa/e tube ,e ( ab\t ! same diamet]1 & :5 !y are fus$ to br+ !m toge!r z at ,,dd 7,fig4 #i74 ,e w !n s]ve z a h&le 9 ! subsequ5t op]ations on ,a4 ,su* a r\gh jo9t z t at ,d mu/ n be all[$ to cool too mu* dur+ ! "w 9 h&1 or ,e & ,a may sep>ate at an inconv5i5t mom5t4 ,or ! glass at ! end ( ! tube may be press$ toge!r to close ! tube1 & ! mass ( glass may be seiz$ ) a pair ( tongs & drawn away4 ,*ok+1 or ,contract+ ! ,bore ( a ,glass ,tube4--,if x be n desir$ to ma9ta9 ! uni=mity ( ext]nal dim5sions ( ! tube :il/ decreas+ ! diamet] ( ! bore1 ! tube may be heat$ & drawn out z describ$ 9 ! description ( seal+ tubes on pp4 #cb-ce4 ,?is may be done z %[n at ,a or ,b 9 ,fig4 #h1 accord+ to ! use to :i* ! contract$ tube is to be put4 ,illu/ration3 ,,fig4 #aj4 ,great] /r5g? & elegance w be secur$ by pres]v+ ! ext]nal diamet] ( ! tube un*ang$ ?r\gh\t1 z %[n 9 ,fig4 #aj4 ,= ?is purpose heat ! tube ) ! po9t$ flame1 if x be small1 or 9 ! bru% flame if x be ( l>ge size1 con/antly rotat+ x till ! glass s(t5s & ! sides %[ an incl9ation to fall toge!r1 :5 ?is occurs1 pu% ! two ends g5tly t[>ds ,a4 ,if ! tube %\ld become too mu* ?ick5$ at ,a1 ! fault may be correct$ by remov+ x f ! flame & g5tly pull+ ! two ends ap>t till x is ( ! prop] size4 ,if ! bore at ! contract$ "p ( ! tube %\ld become too mu* r$uc$1 x may be enl>g$ by clos+ "o end ( ! tube ) a small cork1 & bl[+ g5tly into ! op5 end aft] suffici5tly heat+ ! contract$ "p4 ,! tube %\ld be rotat$ dur+ bl[+ or ! enl>gem5t produc$ may be irregul>4 ,:5 ! ext]nal diamet] ( ! tube is to be increas$ z well z its bore dim9i%$1 press toge!r ! ends ( a tube heat$ at ! "p to be contract$1 z already describ$1 & regulate ! size ( ! bore by bl[+ into ! tube if at any "t x ?reat5s to become too mu* contract$4 ,wid5+ ,tubes4--,tubes may be mod]ately exp&$ at _! extremities by means ( ! *>coal cone 7see ,bord]+1 p4 #ca74 ,!y may be slightly exp&$ at any o!r "p by clos+ "o end & g5tly bl[+ into ! op5 end ( ! tube1 aft] s(t5+ ! glass at ! "p to be wid5$ be=e ! bl[-pipe4 ,b ! be/ me?od ( obta9+ a wide tube ) n>r[ extremities 7,fig4 #aa7 is to jo9 pieces ( n>r[ tube ,,aa to ! ends ( a piece ( wid] tube ,b ( ! desir$ dim5sions4 ,! me?od ( p]=m+ ?is op]ation is describ$ "u weld+1 on pp4 #ci-dg4 ,illu/ration3 ,,fig4 #aa4 ,illu/ration3 ,,fig4 #ab4 ,pi]c+ ,tubes4--,! glass-bl[] v frequ5tly requires to make a l>ge or small op5+ 9 "s "p ( a tube or o!r piece ( app>atus4 ,?is is kn[n z pi]c+4 ,suppose x is desir$ to make a small hole at ! po9t a 9 ,a 7,fig4 #ab74 ,:5 ! tube has be5 br\ght to ! flame ) ! usual precautions1 all[ ! end ( ! po9t$ flame to t\* x at a till an area correspond+ to ! desir$ size ( ! op5+ is ?or\ghly s(t5$4 ,!n exp& ! s(t5$ glass by bl[+ to ! =m %[n at ,b4 ,re-heat a1 bl[ a small globe z at ,c1 & c>efully break ! ?9 glass1 !n smoo? ! r\gh edges by rotat+ !m 9 ! flame till !y =m a m\? l t ( ,d4 ,in/ead ( leav+ ! bulb to be brok5 at ! ?ird /age ,c1 x is a good plan to bl[ m /rongly1 s t ! bulb becomes v ?9 & bur/s1 ! removal ( ! ?9 glass is !n accompani$ by less risk ( produc+ a crack 9 ! ?ick] p>ts ( ! glass4 ,op5+s may be made 9 a simil> mann] 9 ! sides ( tubes or 9 globes1 9 fact1 9 almo/ any position on glass app>atus4 ,if ano!r tube is to be atta*$ at ! op5+1 x is a good plan to proce$ to ?is op]ation be=e ! tube has cool$ d[n4 ,illu/ration3 ,,fig4 #ac4 ,! op5+s obta9$ by ! me?od above describ$ are too l>ge :5 plat9um wires are to be seal$ into !m4 ,suppose t x is necess>y to pi]ce ! tube ,a ( ,fig4 #ac 9 ord] to ins]t a plat9um wire at a2 direct ! smalle/ po9t$ flame t w heat a spot ( glass to r$ness on ! po9t a4 ,:5 ! glass is visc\s1 t\* x ) ! end ( a plat9um wire w1 to :i* ! glass w adh]e2 )draw ! wire & ! visc\s glass w be drawn out into a small tube1 z %[n at ,b2 by break+ ! end ( ?is tube a small op5+ w be made4 ,introduce a plat9um wire into ! op5+1 & aga9 all[ ! flame to play on ! glass at t po9t2 x w melt & close r\nd ! wire4 ,be=e ! hot glass has "t to cool1 bl[ g5tly into ! m\? ( ! tube to produce a slightly curv$ surface1 !n heat ! neighb\r+ p>ts ( ! tube till ! glass is ab\t to s(t51 & let x cool 9 cotton wool4 ,unless ?is is done1 ,i f9d t glass tubes into :i* plat9um wires h be5 seal$ are v apt to break dur+ or aft] cool+4 ,to ensure t ! tube %all be p]fectly air-tight1 a small piece ( :ite enamel %\ld be atta*$ to ! glass at a be=e seal+ 9 ! wire4 ,unit+ ,pieces ( ,glass to ,ea* ,o!r1 kn[n z ,weld+1 or ,sold]+4--,! l>g] & m complicat$ pieces ( glass app>atus are usually made 9 sep>ate sections1 & complet$ by jo9+ toge!r ! sev]al p>ts4 ,?is is !re=e a v important op]ation1 & %\ld be ?or\ghly ma/]$ be=e proce$+ to fur!r "w4 ,9 ord] to produce secure jo9ts1 ! use ( tubes made ( diff]5t k9ds ( glass mu/ be avoid$4 ,soda glass may be jo9$ securely to soda glass1 especially if ! tubes belong to ! same bat*1 & lead glass to lead glass4 ,b1 ?\gh by special c>e a jo9t betwe5 lead glass & soda glass1 if well made1 w (t5 hold toge!r1 yet x is nev] c]ta9 t x w d s4 ,to jo9 two ,tubes ( ,equal ,diamet]s4--,close "o end ( "o ( ! tubes ) a small cork4 ,heat ! op5 end ( ! clos$ tube1 & ei!r end ( ! o!r tube 9 a small flame until !y are almo/ melt$1 tak+ c>e t only ! ends ( ! tubes are heat$1 & n to let ! glass be ?ick5$2 br+ ! two ends toge!r ) suffici5t pressure to make !m adh]e1 b n suffici5t to compress ! glass to a ?ick5$ r+4 ,be=e ! jo9t has "t to cool too mu*1 adju/ y\r bl[-pipe = a po9t$ flame1 if y are n already work+ ) t k9d ( flame1 & all[ ! po9t ( ! flame to play on any spot on ! jo9t till x is heat$ to r$ness2 rotate ! tube a little s z to heat ! glass adjac5t to t :i* is already r$-hot1 & repeat ?is till ! :ole circumf]5ce ( ! r\gh jo9t has be5 heat$4#g ,repeat ! op]ation la/ describ$1 b1 :5 ea* spot is r$-hot1 bl[ g5tly into ! op5 end ( ! tube s z to slightly exp& ! visc\s glass4 ,f9ally1 rotate ! :ole jo9t 9 ! flame till ! glass is s(t5$1 & bl[ g5tly z be=e into ! op5 end ( ! tube1 /ill rotat+ x1 9 ord] t ! jo9t may be z symmetrical z possible4 ,if 9 ! la/ op]ation ! diamet] ( ! jo9t becomes great] ?an t ( ! re/ ( ! tube1 x may be cauti\sly re-heat$ & r$uc$ by pull+ x out1 or ?is may be secur$ by g5tly pull+ ap>t ! two ends1 :il/ ! op]ator bl[s x into its f9al %ape4 #g ,"s glass-bl[]s at once "w on ! glass z next describ$1 )\t ?is prelim9>y treatm5t4 ,i f9d t "s glass1 usually soda glass1 w n always be> ! necess>y movem5ts )\t break+ unless fir/ heat$ all r\nd4 ,illu/ration3 ,,fig4 #ad4 ,:5 small tubes1 or tubes ( f9e bore1 are to be jo9$1 9 ord] to prev5t ! fus$ glass f runn+ toge!r & clos+ ! tube1 x is a good plan to bord] & enl>ge ! ends t are to be unit$1 z at ,a 7,fig4 #ad74 ,"s glass-bl[]s pref] to bord] all tubes be=e unit+ !m4 ,:5 a n>r[ tube is to be jo9$ to "o t is only slightly wid]1 exp& ! end ( ! n>r[ tube till x corresponds 9 size to ! l>g] tube4 ,if ! tube be too n>r[ to be enl>g$ by ins]t+ a *>coal cone1 seal "o end & pi]ce x z direct$ 7on p4 #cg74 ,= jo9+ small ?9-wall$ tubes ,mr4 ,crookes recomm5ds ! use ( a small ,buns5 flame4 ,9 weld+ pieces ( lead glass tube1 take c>e t ! heat$ glass is p]fectly free f r$uc$ lead at ! mom5t :5 ! two ends ( visc\s glass are br\ght into contact4 ,illu/ration3 ,,fig4 #ae4 ,to jo9 ,tubes ( ,unequal ,sizes ,end to ,end 7,fig4 #ae74--;,draw out ! l>g] tube & cut (f ! drawn-out end at ! "p :]e its diamet] is equal to t ( ! small] tube1 !n seal ! small] tube to ! contract$ end ( ! l>g] accord+ to ! directions giv5 = jo9+ tubes ( equal size4 ,:5 a good jo9t has be5 made1 ! tube pres5ts ! appe>ance ( ,a1 ,fig4 #ae1 ! union be+ at ab\t bb4 ,next heat ! :ole tube betwe5 ! dott$ l9es aa1 & bl[ x into ! %ape ( ,b 9 :i* ! dott$ l9e dd %\ld correspond to ! actual l9e ( junction ( ! two tubes4 ,9 mak+ all jo9ts x is important to leave no ?ick masses ( glass ab\t !m4 ,if ! glass be fairly ?9 & uni=mly di/ribut$1 x is less likely to break dur+ or aft] anneal+ "u any circum/ances1 & especially if x has to be> alt]nations ( temp]ature4 ,jo9+ a ,tube to ! ,side ( ano!r ,tube 7,fig4 #af74--,"o ( ! tubes mu/ be pi]c$ z at ,a 9 ,fig4 #af 7= ! me?od1 see p4 #cg71 & its two ends clos$ ) small pieces ( cork4 ,! edges ( ! op5+1 & "o end ( ! o!r tube1 mu/ !n be heat$ till !y melt1 & unit$ by press+ !m toge!r4 ,! jo9t may !n be f9i%$ z be=e4 ,illu/ration3 ,,fig4 #af4 ,a prop]ly bl[n jo9t w n pres5t ! appe>ance ( ,b 7,fig4 #af71 b r t ( ,c4 ,?is is secur$ by direct+ ! po9t$ flame ^u ! glass at aa 7,b7 spot by spot1 & bl[+ out ea* spot :5 x is suffici5tly s(t5$4 ,if ! tubes are l>ge1 ! :ole jo9t %\ld subsequ5tly be heat$ & bl[n1 b 9 ! case ( small tubes ?is is ( less importance4 ,f9ally x is to be wrapp$ :il/ hot 9 cotton wool = ! anneal+ process4 ,if a second tube has to be jo9$ ne> to ! fir/ "o1 say at b1 x is well to proce$ ) x be=e ! jo9t fir/ made cools d[n1 & ! jo9t fir/ made1 especially if soda glass be us$1 mu/ be held 9 ! flame f "t to "t dur+ ! process ( mak+ ! second jo9t to keep x hot2 if ?is be n done ! fir/ jo9t is v likely to break4 ,a jo9t previ\sly made may1 h[ev]1 be re-heat$1 if well made & well anneal$4 ,a ?ree-way tube1 l t 9 ,fig4 #ag1 is made by b5d+ ,a 7,fig4 #af7 to an angle1 & jo9+ ,b to an op5+ bl[n on ! convex side ( ! angle2 or1 ,a ( ,fig4 #af may be b5t z desir$ aft] atta*+ ,b 9 ! ord9>y way4 ,illu/ration3 ,,fig4 #ag4 ,tubes may also be jo9$ to op5+s made 9 ! sides ( globes or flasks2 great c>e mu/ be tak51 h[ev]1 especially if ! walls ( ! globe be ?91 to secure t ! tube is well atta*$ to ! m\? ( ! op5+ :5 ! melt$ ends are fir/ br\ght into contact1 =1 ) ?9 glass1 any hole t may be left w probably increase :il/ ! jo9t is be+ bl[n into %ape1 ow+ to cohesion caus+ ! glass to ga!r 9 a ?ick5$ r+ r\nd an enl>gem5t ( ! orig9al op5+4#h #h ,if su* an op5+ be obs]v$1 x may usually be clos$ by t\*+ its edges ) a fus$ po9t ( glass at ! end ( a drawn out tube4 ,9 ord] to unite a tube ( soda glass to a tube ( lead glass1 ! end ( ! soda glass tube mu/ be c>efully cov]$ ) a lay] ( s(t ars5ic glass4#i ,?is mu/ be done s p]fectly t :5 ! ends to be unit$ are br\ght toge!r ! lead & soda glass are sep>at$ by ! enamel at e po9t4 #i ,?is c be obta9$ f ,messrs4 ,p[ells1 ,:itefri>s ,glassworks4 ,to ,seal a ,tube inside a ,l>g] ,tube or ,bulb4--,suppose t an air-trap 7#c ( ,fig4 #ah7 is to be con/ruct$ f a small bulb 7,a7 bl[n on a glass tube 7#a74 ,illu/ration3 ,,fig4 #ah ,ei!r cut (f ! tube close to ! bulb at ,b1 or bett]1 remove ! end by melt+ ! glass & pull+ x away f ,b1 & !n pi]ce ,a at ,b1 ,no4 #b1 by heat+ ! glass !re & bl[+ out a small bulb z describ$ "u ,pi]c+4 ,prep>e a tube 7#d7 drawn out at ,e ) a bulb bl[n at ,d4 ,ins]t ,e into ! op5+ ,b1 press ,d well aga9/ ! m\? ,b & sl[ly rotate be=e ! bl[-pipe till ,d adh]es to ,b4 ,!n heat & bl[ ! jo9t spot by spot z 9 o!r cases1 tak+ c>e t ! glass is bl[n out on ea* side ( ! jo9t2 la/ly1 heat ! :ole jo9t betwe5 aa1 & bl[ x into its f9al %ape4 ,^! jo9ts are v apt to break aft] a few m9utes or h\rs if ! glass ( ,d be mu* ?ick] ?an t ( ! bulb ,a4 ,!y %\ld be wrapp$ 9 cotton wool = anneal+ z soon z possible1 z ! rate at :i* ! tube ,e cools is likely to be less rapid ?an t ( ! p>ts ( ! app>atus :i* are m freely expos$ to ! air2 !re=e all su* int]nal jo9ts require v c>eful anneal+1 & !y %\ld always be made z ?9 z is consi/5t ) ! use to :i* !y are to be put4 ,tubes may also be seal$ into ! ends or sides ( l>g] tubes by pi]c+ !m at ! po9t at :i* ! ins]t$ tube is to be introduc$1 & proce$+ z 9 ! case ( ! air-trap j describ$4 ,ozone g5]ators ( ! =m %[n on next page 7,fig4 #ai71 af=d an int]e/+ example ( ! ins]tion ( small] tubes into l>g]4 ,on acc\nt ( ! small space t may be left betwe5 ! inn] & out] tubes ( an ozone g5]ator1 & ( ! l5g? ( ! inn] tube1 its con/ruction ne$s great c>e4 ,i f9d ! foll[+ mode ( proc$ure gives good results4 ,select ! pieces ( tube = ?is in/rum5t z free f curvature z possible4 ,= ! inn] tube1 a tube #ab mm41 or r m1 9 ext]nal diamet]1 & ( r ?9 glass1 is drawn out1 z = clos+1 until only a v n>r[ tube rema9s at ,c1 ! end ( ,c is clos$ ! area r\nd ,c is c>efully bl[n into %ape1 s t by melt+ (f ,c ! tube ,a w be left ) a well-r\nd$ end4 ,a small bulb ( glass is next bl[n on ,a at ,b4 ,?is bulb mu/ be ( slightly great] diamet] ?an ! contract$ end ,e ( ! l>g] tube 7,,ii471 s t ,b w j fail to pass ?r\gh ,e4 ,! l5g? f ,b to ,c mu/ n be made great] ?an f ,e to ,g on ! outside tube4 ,! end at ,c is !n to be cut (f s z to leave a p9-hole 9 ! end ( ,a4 ,illu/ration3 ,,fig4 #ai4 ,! out] tube 7,,ii471 ^: diamet] may be #e or #f mm4 great] ?an t ( ,a1 is prep>$ by seal+ a side tube on x at ,f1 aft] previ\sly contract+ ! end ,e4 ,= ?is purpose ! end ,e %\ld be clos$ & r\nd$1 & !n re-heat$ & bl[n out till ! bulb bur/s4 ,to ensure t ! diamet] ( ! op5+ is less ?an t ( ! tube1 c>e mu/ be tak5 n to re-heat too l>ge an area ( ! end be=e bl[+ x out4 ,x is v important t ! cross section at ,e %all be 9 a plane at "r angles to ! axis ( ! tube4 ,wrap a /rip ( writ+ pap]1 "o in* 9 bread?1 closely r\nd ! end ( ,a at ,c till ! tube & pap] w only j pass easily into ! m\? ,d ( ! out] tube1 pu% ! inn] tube ,a1 ) ! pap] ^u x1 into ,d1 & :5 ! pap] is entirely )9 ,d1 )draw ,a1 & cauti\sly pu% ! pap] a little fur!r into ! out] tube4 ,ins]t ,a into ,,de ?r\gh ,e1 s t ! bulb ,b is embrac$ by ,e4 ,close ,d ) a cork4 ,asc]ta9 t ! pap] does n fit suffici5tly tightly betwe5 ! two tubes to prev5t ! free passage ( air1 by bl[+ into ! m\? ,k ( ,a4 ,air %\ld escape freely f ,e :5 ?is is done4 ,gradually br+ ! l9e ( contact ( ,b & ,e & ! surr\nd+ p>ts ( ! tube be=e a po9t$ flame1 aft] previ\sly w>m+ !m by hold+ ne> a l>g] flame1 & rotate !m be=e ! flame s t ! glass may s(t5 & adh]e4 ,!n heat ! jo9t spot by spot z usual4 ,9 bl[+ ?is jo9t1 take c>e t ! glass on ea* side ( ! actual jo9t is slightly exp&$4 ,x %\ld pres5t ! =m %[n by ! dott$ l9es 9 ,,iii4 7^! are purposely exagg]at$1 h[ev]74 ,f9ally1 heat ! :ole jo9t betwe5 ! l9es ,,ji till x s(t5s1 & simultane\sly bl[ & draw x into its f9al %ape z se5 at ,,iii4 ,! side tube ,f %\ld n be too ne> ! end ,e4 ,if1 h[ev]1 x is necess>y to h !m close toge!r1 ! jo9t ,f mu/ be v c>efully anneal$ :5 x is made2 x mu/ also be v cauti\sly w>m$ up be=e ! con/ruction ( ! jo9t at ,h is begun1 & mu/ be kept w>m by lett+ ! flame play ov] x f "t to "t dur+ ! process ( mak+ ! latt] jo9t4 ,a good jo9t may be recognis$ by its fre$om f lumps ( glass1 its regul>ity ( curve1 & by a s5sibly circul> l9e at ,h1 :]e ! two tubes are unit$4 ,:5 ! jo9t aft] anneal+ has become q cold1 ! p9-hole at ,c on ! inn] tube may be clos$1 aft] remov+ ! pap] support1 by w>m+ ! out] tube1 & !n direct+ a f9e po9t$ flame ?r\gh ,d on to ,c4 ,& ! end ,d ( ! out] tube may be clos$ 9 ! ord9>y mann]1 or a n>r[ tube may be seal$ to x4 ,z ! end ( glass at ,d w be too %ort to be held by ! f+]s :5 hot1 ano!r piece ( tube ( simil> diamet] mu/ be atta*$ to x to s]ve z a h&le 7see p4 #ce1 ,fig4 #i74 ,bl[+ a ,bulb or ,globe ( ,glass4--,= ?is purpose x is v important t ! glass tube employ$ %all be ( uni=m sub/ance4 ,! size & ?ickness ( ! tube to be employ$ dep5ds p>tly on ! dim5sions ( ! bulb desir$1 & p>tly on ! size ( neck t is requir$ = ! bulb4 ,x is easi] to bl[ l>ge bulbs on l>ge-siz$ tubes ?an on ^? ( small] size4 ,:5 x is necess>y to make a l>ge globe on a small tube1 x c be done1 h[ev]1 if great c>e be tak5 to avoid ov]heat+ t "p ( ! small tube :i* is ne>e/ to ! mass ( visc\s glass f :i* ! bulb is to be =m$4 ,= ! purpose ( bl[+ a v l>ge bulb on a small tube1 x is be/ to unite a wide tube to t :i* is to s]ve z ! neck1 z x w save "s "t 9 collect+ ! necess>y mass ( glass f :i* to =m ! globe4 ,illu/ration3 ,,fig4 #bj4 ,to bl[ a ,bulb at ! ,end ( a ,tube4--,select a good piece ( tube1 say #a4e cm4 9 diamet]1 & ab\t #cj cm4 long2 draw out "o end to a light tail 7a1 ,fig4 #bj7 ab\t #c in*es 9 l5g?4 ,!n heat up a %ort l5g? ( ! tube at b1 ) a small bru% flame1 by rotat+ ! glass 9 ! flame1 & g5tly press x toge!r :5 s(t to ?ick5 x2 bl[ into x if necess>y to pres]ve ! regul>ity ( its figure4 ,repeat ?is process on ! portion ( tube ne>e/ to t :i* has be5 fir/ ?ick5$1 & s on1 till z mu* glass has be5 heat$ & ?ick5$ z y judge w s]ve to make a bulb ( ! size desir$4 ,y %\ld h a mass ( glass some:at resembl+ t %[n at ,b 7,fig4 #bj71 b probably consi/+ ( ! results ( m successive op]ations ?an are sugge/$ 9 t diagram4 ,apply ! flame z be=e to ! n>r[] p>ts cc ( ,b1 g5tly compress & bl[ until all ! small bulbs fir/ made are br\ght toge!r into a mass /ill some:at resembl+ ! enl>g$ end ( ,b1 b m ne>ly cyl9drical1 ) ! glass z regul>ly di/ribut$ z possible1 & ( su* l5g? f d to ! contract$ "p t ! :ole ( x may easily be heat$ simultane\sly ) ! l>ge bru% flame ( y\r bl[-pipe4 ,take great c>e 9 ! =ego+ op]ations n to all[ ! sides ( ! mass ( glass to fall 9 & run toge!r1 &1 on ! o!r h&1 d n r$uce ! ?ickness ( ! glass ne$lessly by bl[+ x m ?an is necess>y to give ! glass z regul> a =m z possible4 ,:5 y are satisfi$ ) ! mass ( glass y h collect$1 melt (f ! tail a1 & remove ! po9t$ end ( glass t rema9s1 z direct$ on page #cc4 ,turn on z l>ge a bru% flame z is necess>y to envelop ! :ole mass ( glass t y h collect$1 & heat x ) con/ant rotation1 s t x may gradually run toge!r to ! =m se5 at ,c 7,fig4 #bj71 tak+ c>e t x does n get ov]heat$ ne> d1 or ! tube :i* is to =m ! neck w s(t5 & give way4 ,! position 9 :i* ! mass ( heat$ glass is to be held w dep5d ^u circum/ances2 if ! mass ( glass be n too great1 x is be/ to keep x 9 a ne>ly horizontal position4 ,if ! mass ( glass be v l>ge1 x may be necess>y to incl9e ! end ,b d[nw>ds2 b z t is apt to result 9 an excess ( glass accumulat+ t[>ds d1 avoid do+ s if possible by rotat+ ! glass /eadily & rapidly4 ,if at any "t ! glass %[s indications ( collaps+1 x mu/ be remov$ f ! flame & g5tly bl[n into %ape1 dur+ :i* op]ation x may be rotat$ 9 ! p]p5dicul> position2 inde$1 to promote a regul> di/ribution ( ! glass by all[+ x pl5ty ( "t to collect1 x is well f "t to "t to remove ! heat$ mass ( glass f ! flame1 & slightly exp& x by bl[+4 ,f9ally1 :5 a regul> mass ( glass1 su* z is %[n at ,c 7,fig4 #bj7 has be5 obta9$1 remove x f ! flame1 & bl[ x to its f9al dim5sions4 ,a succession ( g5tle puffs quickly succe$+ ea* o!r %\ld be employ$1 9 ord] t ! progress ( ! bulb may be m easily wat*$ & arre/$ at ! "r mom5t4 ,dur+ ! process ( bl[+1 ! hot glass mu/ be /eadily rotat$4 ,to collect ! glass = bl[+ a bulb ( lead glass1 employ ! flame describ$ on pp4 #ag-bb = heat+ lead glass4 ,if ! tube be held horizontally :il/ ! globe is bl[n1 its =m w mo/ ne>ly approa* t ( a true globe4 ,if x be held 9 ! p]p5dicul> position1 ) ! mass ( glass dep5d+ f x1 ! =m ( ! bulb w usually be some:at elongat$4 ,if x be held p]p5dicul>ly1 ) ! mass ( glass upw>ds1 ! result+ bulb w be flatt5$4 ,:5 a bulb is n ( a suffici5tly regul> =m1 x may sometimes be re-made by re-collect+ ! glass1 & re-bl[+ x4 ,! greate/ c>e is ne$$ at ! e>li] /ages ( re-heat+ to prev5t ! glass f collaps+ into a =mless & unworkable mass4 ,?is is to be prev5t$ 9 all su* cases by g5tly bl[+ x into %ape f "t to "t :il/ ga!r+ ! glass4 ,illu/ration3 ,,fig4 #ba4 ,to bl[ a ,bulb betwe5 two ,po9ts 7,fig #ba74--,select a piece ( suitable tube1 seal or cork "o end1 ga!r toge!r a mass ( glass at ! desir$ "p1 z direct$ = bl[+ a bulb at ! end ( a tube2 :5 a mass ( glass has be5 collect$ ( suffici5t ?ickness1 bl[ x into %ape f ! op5 end ( ! tube by a rapid succession ( %ort bla/s ( air1 till ! exp&+ glass atta9s ! desir$ dim5sions4 ,! tube mu/ be held horizontally1 & mu/ be rotat$ /eadily dur+ ! process4 ,by slightly press+ toge!r ! glass :ile bl[+1 ! bulb w be flatt5$2 by slightly draw+ ap>t ! two ends ( ! tube1 x w be elongat$4 ,a pe>-%ap$ bulb may be obta9$ by g5tly re-heat+ an elongat$ bulb1 say f a to a1 & draw+ x out4 ,x is easie/ to p]=m ?is op]ation on a bulb :i* is r ?ick 9 ! glass4 ,if ! tubes bb are to be small1 & a globe ( consid]able size is want$1 contract a tube z %[n 9 ,fig4 #bb1 tak+ c>e t ! n>r[ portions ( ! tube are ab\t ! same axis z ! wid] portions1 = if ?is be n ! case1 ! m\?s ( ! bulb w n be symmetrically plac$2 seal at ,c1 cut (f ! wid] tube at ,b1 & make ! bulb1 z previ\sly describ$1 f ! glass betwe5 ,,aa4 ,if1 z probably w be ! case1 ! contract$ portions ( ! tube be n v regul>1 !y may be cut (f1 "o at a "t1 ne> ! bulb1 & replac$ by pieces ( tube ( ! size desir$4 ,illu/ration3 ,,fig4 #bb4 ,:5 a bulb has to be bl[n ^u a v f9e tube1 = example ^u !rmomet] tub+1 ! m\? %\ld n be employ$1 = ! moi/ure introduc$ by ! brea? is extremely difficult to remove aft]w>ds4 ,a small india-rubb] bottle or res]voir1 su* z ^? :i* are us$ 9 spray-produc]s1 ,galton's :i/les1 etc41 securely atta*$ to ! op5 end ( ! tube1 %\ld be us$4 ,) ! help ( ^! bottles bulbs c be bl[n at ! clos$ ends ( f9e tubes ) ease1 ?\gh "s c>e is necess>y to produce !m ( good %ape1 z x is difficult to rotate ! hot glass prop]ly :5 work+ 9 ?is way4 ,mak+ & ,gr9d+ ,/opp]s4--,app>atus :i* is to conta9 *emicals t are likely to be affect$ by ! free admission ( air1 ne$s to h /opp]s fitt$ to x4 ,mak+ a good /opp] is a mu* less t$i\s process ?an is commonly suppos$4 ,suppose t ! tube ,i4 ( ,fig4 #bc is to be /opp]$ at ,a1 x mu/ be slightly enl>g$ by s(t5+ ! end & op5+ x ) a po9t$ cone ( *>coal2 or a conical m\? = ! /opp] may be made by slightly contract+ ! tube ne> "o end1 z at ,b1 cutt+ (f ! cyl9drical end ( ! tube at ! dott$ l9e ,c1 & !n v slightly exp&+ ! end at ,c ) a *>coal cone aft] its edges h be5 s(t5$ by heat4 ,9 ei!r case ! conical m\? %\ld be z long & regul> z possible4 ,illu/ration3 ,,fig4 #bc4 ,= ! /opp] take a piece ( r ?ick tube1 ( su* size t x w pass easily1 b n too easily1 into ,a or ,b4 ,exp& ?is tube at ,d1 z %[n 9 ,,ii41 by s(t5+ ! glass & g5tly compress+ x4 ,! configuration ( ! enl>g$ tube z %[n at ,d may be obta9$ by heat+ & compress+ two or m zones ( ! tube t are adjac5t1 "o zone be+ less exp&$ ?an ! o!r1 s z to give ! sides ( ! imp]fect /opp] z ne>ly z possible ! =m %[n at ,d1 :i*1 h[ev]1 is mu* less regul> ?an may easily be obta9$4 ,seal (f ! head ( ! tube at ,h1 & heat ! glass till x runs toge!r into a ne>ly solid mass2 compress ?is ) a pair ( iron tongs to ! flatt5$ head ,e4 ,9 mak+ ,d1 aim at giv+ x a =m :i* w z ne>ly z possible correspond to t ( ! tube into :i* x is to be gr\nd1 & make x slightly too l>ge1 s t only ! l[] "p at ,d c be introduc$ into ! m\? ( ,a or ,b4 ,be=e x is gr\nd1 ! /opp] mu/ be heat$ ne>ly to its s(t5+-po9t & anneal$4 ,moi/5 ,d ) a solution ( camphor 9 rec5tly di/ill$ turp5t9e1 & du/ ! wet surface ) f9ely-gr\nd em]y1 !n g5tly gr9d x into its place till x fits prop]ly4 ,9 ?is op]ation ! tail ,g1 :i* %\ld fit loosely into ! tube ,a1 w be ( assi/ance by prev5t+ ,d f unduly press+ 9 any direction on ,a 9 consequ5ce ( irregul> movem5ts4 ,! /opp] %\ld be completely rotat$ 9 gr9d+ x4 ,x mu/ n be work$ backw>ds & =w>ds1 or a well-fitt+ /opp] w n be produc$4 ,r5ew ! em]y & camphorat$ turp5t9e frequ5tly dur+ ! e>li] "p ( ! gr9d+2 :5 ! /opp] almo/ fits1 avoid us+ fre% em]y1 b cont9ue to remove ! /opp] frequ5tly at all /ages ( ! op]ation4 ,t add$ at ! e>li] /ages w be r$uc$ to a /ate ( v f9e division1 & w !re=e leave ! /opp] & m\? ( ,a ) smoo!r surfaces ?an fre% em]y4#aj #aj ,mr4 ,gimm+ham recomm5ds giv+ /opp]s a f9al poli% ) rott5-/one 7,proce$+s ( ! ,royal ,society1 p4 #cif1 #ahgf74 ,,note4--,! addition ( camphor to ! turp5t9e us$ = gr9d+ glass is v important4 ,not)/&+ its brittle nature1 glass w "w "u a file moi/5$ ) ?is solution almo/ z well z ! metals4 ,small quantities %\ld be made at a "t1 & ! solution %\ld be kept 9 a well-clos$ vessel1 = aft] long exposure to ! air x is n equally valuable4 ,if ! /opp] is to fit a tube contract$ l ,b1 x mu/ be con/ruct$ f a piece ( tube t w pass ?r\gh ! contraction at ,b4 ,! tail ,,gf w n d su* good s]vice z x does 9 ! case ( a tube :i* has be5 op5$ out to receive its /opp]1 b x w help to guide ! /opp]1 & %\ld be reta9$4 ,:5 ! /opp] has be5 gr\nd into its place1 melt (f ! tail at ,f4 ,! flame mu/ be appli$ v cauti\sly1 z glass :i* has be5 gr\nd is p>ticul>ly apt to crack on heat+4 ,to avoid all risk ( ?is1 ! tail may simply be cut (f1 & its edges fil$ smoo? ) a file moi/5$ freely ) camphorat$ turp5t9e4 ,! /opp]s ( bottles are n made exactly 9 ! mann] describ$ above1 ?\gh1 on occasion1 a new /opp] may be made = a bottle by foll[+ ^? directions4 ,ill-fitt+ /opp]s1 :i* are v common1 c be v easily re-gr\nd ) em]y & camphorat$ turp5t9e4 ,,*apt] ,,iv4 ,,mak+ ,,?i/le ,,funnels1 ,u-,,tubes1 ,,etc4--,,comb9+ ,,! ,,p>ts ,,( ,,complicat$ ,,app>atus--,,m]cury1 ,,& ,,o!r ,,air-,,tight ,,jo9ts--,,vacuum ,,taps--,,safety ,,taps--,,air-,,traps4 ,9 ,*apt] ,,iii4 ! simpl] op]ations us$ 9 mak+ ! sep>ate p>ts ( :i* app>atus is compos$ h be5 describ$4 ,9 ?is ,*apt] f9i%$ app>atus w be describ$1 & ! comb9ation ( ! sep>ate p>ts into ! m or less complicat$ arrangem5ts us$ 9 exp]im5ts w be s f> expla9$ z to enable ! /ud5t to set up su* app>atus z he is likely to require4 ,i h ?\ght x w\ld be useful t ,i %\ld add a %ort acc\nt ( v>i\s contrivances t h come mu* into use ( late ye>s = exp]im5t+ "u r$uc$ pressure1 su* z safety taps1 air-traps1 vacuum jo9ts1 etc4 ,illu/ration3 ,,fig4 #bd4 ,electrodes4--,on page #ch 7,fig4 #ac7 is %[n a simple =m ( electrode seal$ into a glass tube1 :i* = _m purposes answ]s v well4 ,b frequ5tly1 9 ord] t !re may be less risk ( leakage betwe5 ! glass & ! metal1 ! latt] is cov]$ = a consid]able "p ( its l5g? ) solid glass1 :i* at "o extremity is unit$ to ! app>atus4 ,9 ,fig4 #bd ,w is ! metal core ( ! electrode1 & ,g ! glass cov]+ ar\nd x4 ,! wire is fus$ into ! glass1 & ! glass is !n unit$ to ! app>atus2 a little :ite enamel %\ld be appli$ at "o end & comb9$ ) ! glass by fusion4 ,u-,tubes4--,a ,u-tube is b a p>ticul> case ( a b5t glass tube4 ,x is sc>cely possible :5 b5d+ v l>ge tubes 9 ! mann] describ$ on p4 #bi to produce regul> curves ( suffici5t /r5g?4 ,to make a ,u-tube1 or to b5d a l>ge tube1 close "o end ( ! tube select$ ) a cork1 s(t5 & compress ! glass 9 ! flame at ! "p :]e x is to be b5t till a suffici5t mass ( glass = ! b5d is collect$1 !n remove ! mass ( glass f ! flame1 let x cool a little1 & simultane\sly draw out ! ?ick5$ glass1 b5d x to ! prop] =m1 & bl[ ! b5d into %ape f ! op5 end ( ! tube4 ,small irregul>ities may be p>tly correct$ aft]w>ds4 ,to make a good ,u-tube ( l>ge size1 & ( uni=m diamet] f end to end1 requires mu* practice1 b to make a tol]ably pres5table piece ( app>atus 9 :i* ! two limbs are b5t r\nd till !y are p>allel1 )\t any consid]able con/riction at ! b5d1 c be accompli%$ )\t mu* difficulty4#aa #aa ,l>ge tubes may also be b5t by rotat+ a suffici5t l5g? ( ! tube 9 a l>ge flame till x s(t5s1 & b5d+ 9 ! same mann] z 9 ! case ( small] tubes1 & aft] fill+ !m ) s&1 clos+ "o end completely1 & ! o!r s t ! s& _c escape1 ?\gh heat$ air c d s4 ,spiral ,tubes4--,^! may be made by twi/+ a tube gradually s(t5$ by heat r\nd a metal cyl9d]4 ,spiral tubes made ( small ?9 tubes possess consid]able ela/icity1 & h be5 us$ by ,mr4 ,crookes = mak+ air-tight connections betwe5 sep>ate pieces ( app>atus :5 a rigid connection w\ld h be5 unnecess>y & inconv5i5t4 ,by ! use ( su* spiral tubes x is possible to comb9e comp>atively free movem5t ) all ! advantages atta*$ to h]metically-seal$ jo9ts4 ,to make a flexible spiral tube1 m\nt a copp] cyl9d] on a screw1 s t ! cyl9d] w travel 9 ! direction ( its axis :5 x is rotat$4 ,fix a f9e glass tube to ! cyl9d]1 & direct a flame t[>ds ! cyl9d] s z to heat & s(t5 ! glass1 :i* w !n b5d to ! =m ( ! cyl9d]4 ,gradually rotate ! cyl9d] be=e ! s\rce ( heat1 s t fre% portions ( tube are successively br\ght into position1 s(t5$1 & b5t4 ,useful spirals may also be made by h& )\t a cyl9d]4 ,z ea* l5g? ( tube is b5t1 a fre% l5g? may be unit$ to x until ! spiral is complet$4 ,! f9e tubes employ$ are prep>$ by heat+ & draw+ out l>g] tubes4 ,illu/ration3 ,,fig4 #be4 ,?i/le ,funnels 7,fig4 #be74--,seal a mod]ately ?ick piece ( small glass tube at ,a1 !n heat a wide zone ( x a little bel[ ,a by rotat+ x horizontally 9 ! bl[-pipe flame till ! glass s(t5s1 & exp& ! glass to a bulb1 z %[n at ,b ( #a2 dur+ ! op]ation ( bl[+ ?is bulb1 ! end ,a mu/ be direct$ to ! gr\nd4 ,s(t5 ! end ,a & a small portion ( ,b z be=e1 &1 hold+ ! tube horizontally f ! m\?1 bl[ out ! end ,c z at #b4 ,heat ! end ( ,c gradually1 till ! glass s(t5s & collapses to ! dott$ l9e dd1 & at once bl[ a /eady /ream ( air into ! op5 end ( ! tube1 rotat+ x /eadily1 till x is ab\t to bur/2 f9ally clean (f ! ?9 glass f r\nd ! edges ( ! funnel1 :i* %\ld h ! =m %[n at #c1 & r\nd !m4 ,an inspection ( a pur*as$ ?i/le funnel w g5]ally %[ t ! head ,b has be5 =m$ f a l>g] tube seal$ to ,e at f4 ,illu/ration3 ,,fig4 #bf4 ,clos+ ,tubes conta9+ ,*emicals = exp]im5ts at high temp]atures4--,tubes ( ! h>d glass us$ = organic analyses answ] be/ = ?is purpose2 ! op]ation ( draw+ out ! end ( su* a tube is practically id5tical ) :at has be5 describ$ "u ! head ( *ok+1 p4 #ce4 ,a well-seal$ tube pres5ts ! appe>ance ( t %[n by ,fig4 #bf4 ,9 ord] to secure a ?ick end to ! po9t ( ! tube a1 ab\t an in* or s ( ! tube ne> ! contract$ "p %\ld be w>m$ a little1 if x is n already w>m1 at ! mom5t ( f9ally seal+ x2 ! contraction ( ! air 9 ! tube1 9 consequ5ce ( ! cool+ ( ! w>m tube1 w !n ensure ! glass at a runn+ toge!r to a solid end :5 x is melt$ 9 ! flame4 ,if x w be necess>y to collect a gas produc$ dur+ a *emical action f su* a tube1 make ! contract$ end sev]al in*es long1 & b5d x into ! =m ( a deliv]y tube4 ,x w !n be possible to break ! tip ( ?is "u a cyl9d] 9 a tr\gh ( liquid4 ,9 ord] to expla9 ! con/ruction ( app>atus consi/+ ( sev]al p>ts1 x w be suffici5t to take z examples1 two v well-kn[n in/rum5ts1 & to describe _! con/ruction 9 detail4 ,f :at is le>n$ 9 /udy+ ^!1 ! /ud5t w ga!r ! in=mation t is want$4 ,illu/ration3 ,,fig4 #bg4 #a4 ,to make ,h(man's ,app>atus = ! electrolysis ( wat] 7,fig4 #bg74 ,take two tubes ab\t #ce cm4 9 l5g?1 & #ad mm4 9 diamet] = ,,aa1 jo9 taps ,,tt to ! end ,b ( ea* ( !m1 draw out ! o!r end1 z %[n at ,d1 aft] %eets ( plat9um foil ) wires atta*$ to !m#ab h be5 introduc$ into ! tubes1 & mov$ by %ak+ to ,,bb4 ,!n all[ ! plat9um wires to pass ?r\gh ! op5+ ,d left = ! purpose1 & seal ! glass at ,d r\nd ! plat9um z at ,e4 ,pi]ce ! tubes at ,,jj1 & jo9 !m by a %ort piece ( tube ,k1 ab\t #ad mm4 9 diamet]1 to :i* ! tube ,t1 c>ry+ ! res]voir ,r1 has be5 previ\sly unit$4 ,r may be made by bl[+ a bulb f a l>g] piece ( tube atta*$ to ! end ( ,t4 ,! m\? ,m ( ! res]voir be+ =m$ f ! o!r end ( ! wide tube aft]w>ds4 ,"o ( ! taps c be us$ = bl[+ ?r\gh at ! lat] /ages4 ,ea* jo9t1 especially ^? at ,,jj1 mu/ be anneal$ aft] x is bl[n4 ,"s op]ators might pref] to jo9 ,,aa by ! tube ,k 9 ! fir/ in/ance1 !n to introduce ! electrodes at ,e & ,d4 ,9 "s respects ?is plan w\ld be r easi] ?an ! o!r1 b1 on ! :ole1 x is bett] to make ! jo9ts at ,,jj la/ 9 ord]1 z !y are m apt to be brok5 ?an ! o!rs dur+ ! subsequ5t manipulations4 #ab ,r$-hot plat9um welds v well4 ,! wire may be jo9$ to ! %eet ( foil by plac+ ! latt] on a small piece ( fire-brick1 hold+ ! wire 9 contact ) x at ! place :]e !y are to be unit$1 direct+ a bl[-pipe flame ^u !m till !y are at an int5se heat1 & sm>tly /rik+ ! wire ) a hamm]4 ,! bl[ %\ld be sev]al times repeat$ aft] re-heat+ ! metal4 #b4 ,i h be=e me ! vacuum tube %[n by ,fig4 #bh1 9 :i* ! dott$ l9es relate to details ( manipulation only4 ,illu/ration3 ,,fig4 #bh4 ,x is usually possible to detect ! p>ts ( :i* a piece ( app>atus has be5 built up1 = ev5 ! be/-made jo9ts exhibit evid5ce ( _! exi/5ce4 ,?us1 al?\gh ,i did n make ! tube t is be=e me1 & _c !re=e pret5d to say precisely 9 :at ord] its p>ts 7 made & put toge!r1 ! evid5ce :i* x exhibits ( jo9ts at ! dott$ l9es ,a1 ,b1 ,c1 ,d1 ,e1 ,f1 enables me to give a g5]al idea ( ! processes employ$ 9 its con/ruction1 & to expla9 h[ a simil> tube might be con/ruct$4 ,i %\ld advise proce$+ z foll[s3-- ,jo9 a piece ( tube some:at l>g] ?an ,m to its end ,a1 draw out ! o!r end ( ! l>g] tube1 & bl[ a bulb ,l z direct$ on p4 #dg4 ,!n seal ! electrode ,r into ! bulb ,l 7p4 #ee74 ,bl[ a simil> b l>g] bulb ,n f a l>ge piece ( tube seal$ betwe5 two tubes ( simil> size to ,m1 z describ$ at p4 #ej4 ,cut (f "o ( ! tubes at ,b1 & jo9 ! bulb ,n to ,m at ,b4 ,=m ! bulb ,q 9 ! same mann] z 9 ! case ( ,l1 seal into x ! electrode ,r1 & add ! tube m>k$ by ! dott$ l9es at ,f4 ,seal a n>r[ tube ,p to ! end ( a l>g] tube1 & bl[ out ! tube at ! jo9t till ! glass is ?9 & regul>4 ,take a tube ,o1 ( simil> size to ,m1 slightly long] ?an ,p1 contract its m\? slightly to meet ! wide end ( ,p at ,d1 & aft] loosely support+ ,p inside ,o ) a cork1 or o!rwise1 close ! end ,n ( ,o by seal+ or cork+ x1 & jo9 ,p to ,o at ,d4 ,cut (f ,o j above ,d at ,e1 & jo9 x to ! bulb ,q1 clos+ ei!r ,o or ,f = ! purpose4 ,cut (f ! end ( ,o at ,c p>allel to ! end ( ,p1 & connect ,o to ,n1 us+ ,f = bl[+ ! jo9t at ,c4 ,f may be us$ subsequ5tly = introduc+ any gas into ! tube1 &1 :5 a vacuum has be5 e/abli%$1 may be seal$ be=e ! bl[-pipe4 ,illu/ration3 ,,fig4 #bi4 ,modes ( comb9+ ! ,p>ts ( ,heavy ,app>atus4--,x is (t5 necess>y to connect pieces ( app>atus :i* are too heavy to be freely h&l$ be=e ! bl[-pipe1 & :i*1 !re=e1 _c be weld$ toge!r z describ$ on p4 #ci1 by "s m effective me?od ?an ! ord9>y "o ( connect+ by india-rubb] tub+4 ,= example1 app>atus :i* is to be exhau/$ by a ,spr5gel air-pump mu/ be atta*$ to ! pump by a jo9t z p]fectly air-tight z c be obta9$4 ,?is1 inde$1 (t5 may be done by weld+ ! app>atus to be exhau/$ to ! air-pump be=e ! bl[-pipe4 ,b su* a me?od is op5 to ! obvi\s objection t x is v tr\blesome to connect & disconnect ! p>ts z (t5 z may be necess>y1 & t !re is "s risk ( accid5tal breakages4 ,nev]!less x may be done on occasion1 especially if !re be no objection to ! use ( ! flexible spiral tubes already allud$ to4 ,:5 ! use ( a spiral connect+-tube is n admissible ! difficulty is consid]ably increas$4 ,= example1 ! au?or has lately requir$ to atta* an ozone g5]ator1 ( ! =m %[n by ,fig4 #ai1 :i* previ\sly _h be5 cem5t$ into a heavy copp] jacket1 to a pressure-gauge rigidly fix$ to a support1 & ( consid]able size4 ,! employm5t ( a flexible spiral connection 0 prohibit$ by ! fact t x 0 necess>y t ! volume ( ! connect+-tube %\ld be b a small fraction ( t ( ! ozone g5]ator1 a condition :i* compell$ ! use ( a tube ( almo/ capill>y bore1 & ( inconsid]able l5g?4 ,at ! same "t ! frailness ( su* a connection made x necess>y to fix ! g5]ator & pressure-gauge rigidly to _! supports1 9 ord] to avoid ! possibility ( breakage by slight accid5tal movem5ts ( ei!r ( !m1 & x 0 obvi\sly necess>y to fix ! pieces ( app>atus 9 _! f9al positions be=e jo9+ !m1 le/ ! f9e tube :i* connect$ !m %\ld be fractur$ dur+ adju/m5t4 ,! possibility ( a /ra9 be+ caus$ by ! contraction t w\ld occur dur+ ! cool+ d[n ( ! jo9t la/ made _h to be provid$ = also4 ,! desir$ object 0 effect$ z foll[s4 ,9 ,fig4 #bi ,a repres5ts a section ( ! ozone g5]ator at ! po9t :]e ! tube to connect x to ! gauge 0 fix$4 ,b repres5ts ! top ( ! gauge1 ) ! side tube ,c1 :i* 0 to be connect$ ) t f ,a1 viz4 ,d4 ,! ends ( ,c & ,d 7 exp&$ z %[n at ,d 7by melt+ !m & bl[+ !m out71 s t "o ( !m1 made r small] ?an ! o!r1 c\ld be ov]lapp$ by ! l>g] "o4 ,a & ,b be+ rigidly fix$ 9 _! f9al positions1 ) ,c & ,d 9 contact1 z %[n 9 ! figure1 all op5+s 9 ! app>atus 7 clos$1 except "o1 to :i* 0 atta*$ an india-rubb] bl[+-bottle by means ( a tube ( india-rubb] long en\gh to be held 9 ! h& ( ! op]ator1 & to all[ him to obs]ve ! op]ation ( jo9+ ! tubes at ,d4 ,:5 ev]y?+ 0 9 read9ess1 a v small-po9t$ flame f a moveable bl[-pipe held 9 ! h& 0 direct$ ^u ! glass at ,d till x melt$ & ! two tubes unit$4 ,to prev5t ! f9e tube :5 melt$ f runn+ into a solid mass ( glass1 & s becom+ clos$1 a slight excess ( pressure 0 ma9ta9$ inside ! app>atus dur+ ! op]ation by =c+ air into x ) ! india-rubb] bl[] f ! mom5t at :i* ,c & ,d unit$4 ,a po9t ( *>coal 0 kept 9 read9ess to support ! s(t5$ glass at ,d 9 case x %[$ any t5d5cy to fall out ( %ape4 ,! ,v-tube at ,c s]v$ to prev5t ! subsequ5t fracture ( ! jo9t 9 consequ5ce ( any /ra9 caus$ by ! contraction ( ! glass 9 cool+4#ac #ac ,= a me?od ( jo9+ soda glass to lead glass1 see p4 #ha4 ,x is n difficult to connect sev]al pieces ( app>atus successively 9 ?is mann]1 nor is ?is me?od only useful 9 su* cases z t j describ$4 ,pieces ( app>atus ( great l5g? & weight may be jo9$ 9 a simil> mann]1 irrespective ( ! size ( ! tubes to be unit$4 ,! ends to be jo9$1 prep>$ z be=e1 s t "o slightly ov]laps ! o!r1 mu/ be held firmly 9 contact by clamps1 & heat$ 9 successive portions by a bl[-pipe held 9 ! h& ( ! op]ator1 ea* pat* ( glass be+ re-heat$ & g5tly bl[n1 aft] a r\gh jo9t has be5 made4 ,f9ally1 a l>g] flame may be us$ to heat up ! :ole jo9t = its f9al bl[+4 ,x is important to place ! app>atus s t ! op]ator has free access to x on all sides4 ,a revolv+ table might be employ$4 ,an assi/ant to "w ! bell[s is necess>y4 ,or1 bett] /ill1 air may be admitt$ to ! bl[-pipe f a l>ge gas-bag plac$ 9 "s conv5i5t position4 ,b 9 mo/ cases "o or o!r ( ! foll[+ air-tight jo9ts c be employ$1 & w be f\nd to be v conv5i5t3-- ,m]cury ,jo9ts4--,! simple/ =m ( m]cury jo9t is %[n at ,fig4 #cj4 ,a & ,b are ! two tubes :i* are to be connect$4 ,a l>g] tube or cup ,f is atta*$ to ,a by ! india-rubb] tube ,e1 & plac$ on ,a s t ! end ( ,b may be br\ght into contact ) ,a at ,c1 & connect$ to x by a well-fitt+ piece ( india-rubb] tube ,c4 ,! cup ,e is !n br\ght into ! position %[n 9 ,fig4 #cj1 & m]cury is introduc$ till ! india-rubb] tube at ,c is cov]$4 ,z m]cury & glass d n come into true contact1 h[ev]1 su* a jo9t1 ?\gh said to give good results 9 practice1 is n !oretically air-tight1 = air might gradually f9d its way betwe5 ! liquid & ! glass4 ,by cov]+ ! m]cury ) a little sulphuric acid or glyc]9e ! risk ( ?is occurr+ may be remov$4 ,! same result may be atta9$ by ! use ( glyc]9e 9 place ( ! m]cury 9 ! cup ,f2 b glyc]9e is less pleasant to "w ) ?an m]cury4#ad #ad ,if ! india-rubb] tube ,c be secur$ by wires1 iron wire1 n copp] wire1 %\ld be employ$4 ,illu/ration3 ,,fig4 #cj4 ,:5 sulphuric acid is to be employ$ 9 su* a jo9t1 or :5 = any o!r reason ! use ( an india-rubb] tube is undesirable1 ! jo9t may consi/ ( a holl[ /opp] ,b 7,fig4 #ca71 made ( glass tube1 & gr\nd to fit ! neck ( a ?i/le funnel ,a4 ,a & ,b are jo9$ respectively to ! pieces ( app>atus to be connect$1 & connection is made by plac+ ,b 9 position 9 ! neck ( ,a2 ! jo9t is made air-tight by introduc+ m]cury ) /rong sulphuric acid above x into ! cup ,a4 ,! jo9t may be r5d]$ air-tight by introduc+ sulphuric acid only into ! cup4 ,b ?is plan mu/ n be adopt$ if ! int]ior ( ! app>atus is to be exhau/$1 z sulphuric acid is easily =c$ betwe5 ! gr\nd glass surfaces by ext]nal pressure4 ,m]cury1 h[ev]1 w n pass betwe5 well-gr\nd glass surfaces1 & is !re=e to be employ$ = connect+ app>atus :i* is to be exhau/$1 &1 if necess>y1 protect$ by a lay] ( /rong sulphuric acid to completely exclude air4 ,illu/ration3 ,,fig4 #ca4 ,tubes plac$ horizontally may be jo9$ by a glyc]9e or m]cury jo9t su* z is %[n 9 ,fig4 #cb4 ,! two tubes ,a & ,b are jo9$ z be=e by an india-rubb] connection ,c1 or "o may be gr\nd to fit ! o!r1 & ! jo9t is !n enclos$ )9 a l>g] jacket+-tube ,d1 ) a m\? at ,f1 :i* is fill$ ) glyc]9e or m]cury4 ,d is easily made by draw+ out bo? ends ( a piece ( tube1 leav+ !m l>ge en\gh to pass ov] ! connection at ,c1 h[ev]1 & pi]c+ "o side at ,f4 ,illu/ration3 ,,fig4 #cb4 ,vacuum ,taps4--,x is n necess>y to ent] into a description ( ! con/ruction ( ord9>y glass taps1 :i* c be pur*as$ at v reasonable prices4 ,x may be rem>k$ "h1 h[ev]1 z a great _m ( !m are v imp]fectly gr\nd by ! mak]s1 t !y may easily be made air-tight by h&-gr9d+ ) camphorat$ turp5t9e & f9e em]y1 f9i%+ ) rott5-/one4 ,a well-gr\nd tap1 :i* is well lubricat$1 %\ld be practically air-tight "u greatly r$uc$ pressure = a %ort p]iod2 b :5 x is necess>y to h a tap :i* absolutely =bids ! entrance ( air into app>atus1 "o ( ! foll[+ may be employ$3-- ,illu/ration3 ,,fig4 #cc4 ,illu/ration3 ,,fig4 #cd4 7#a47 ,mr4 ,cetti's ,vacuum ,tap 7,fig4 #cd73 ,?is tap is cupp$ at ,a & seal$ at ,b1 & ! cup ,a is fill$ ) m]cury :5 ! tap is 9 use1 s t if1 = example1 ! end ,c be atta*$ to a flask1 & ,d to an app>atus = exhau/+ ! flask1 x w be possible to close ! flask by turn+ (f ! tap ,e1 & if no air be all[$ access ?r\gh ,d1 ! vacuum produc$ 9 ! flask at ,c _c be affect$ by air leak+ ?r\gh ! tap at ,a or ,b4 ,a passage ,f mu/ be drill$ f ! bottom ( ! plug ,e to meet ,g1 9 ord] t :5 ! plug is 9 position no residue ( air %all be conf9$ )9 ,b1 :5ce x might gradually leak into any app>atus connect$ to x4 ,x is obvi\s1 h[ev]1 t ?is tap does n protect a flask seal$ to ,c f ! entrance ( air ?r\gh ,d1 :i*1 9 fact1 is ! direction 9 :i* air is mo/ likely to effect an entrance4 ,:5 us+ "o ( ^! taps z "p ( an app>atus = supply+ pure oxyg51 ,i h gu>d$ aga9/ ?is by atta*+ a trap 7,fig4 #cc7 to ! end ,d1 ,c be+ jo9$ to ! deliv]y tube f ! gas-hold]4 ,! /ructure & mode ( action ( ! trap are z foll[s3-- ,a n>r[ tube ,g is jo9$ to ,d ( ,fig4 #cd1 & t]m9ates 9 ! wide tube ,i1 :i* is connect$ above to ,h1 & bel[ to ! air-trap ,j4 ,j is connect$ at ,k1 by a piece ( flexible tube1 to a res]voir ( m]cury1 f :i* m]cury ent]s ! air-trap1 & pass+ !nce to ,i1 c be employ$ = fill+ ! ,v-trap ,,hlg4 ,! air-trap ,j is 9 ! fir/ in/ance fill$ ) m]cury1 & !n s]ves to int]cept any /ray bubbles ( air t ! m]cury may c>ry ) x4 ,! p>ticul> =m ( ! trap %[n at ,,hlg 0 adopt$ because ) x ! arm ,,lg is m readily empti$ ( m]cury ?an ) any o!r =m ( trap made ( small tube t ,i h tri$4 ,x has be5 us$ 9 my app>atus 9 ! foll[+ mann]3--,h 0 connect$ ) a vessel to be fill$ ) pure oxyg51 ! tap ,e clos$1 & ! rise ( m]cury above ,l prev5t$ by a clamp on ! flexible tube2 ! vessel to be fill$ & ! trap 7 !n exhau/$ by a ,spr5gel pump1 & oxyg5 all[$ to fl[ into ! exhau/$ space by op5+ ,e1 ! op]ation ( exhau/+ ! tubes & admitt+ oxyg5 be+ repeat$ z (t5 z necess>y4 ,to prev5t access ( air to ,e on disconnect+ ! vessel at ,h1 ! m]cury 0 all[$ to fl[ into ! trap till x rea*$ to ,,mm4 ,e 0 !n clos$1 & ,h expos$ )\t dang] ( air rea*+ ,e1 ! l5g? ( ! arms ( ! trap be+ suffici5t to provide aga9/ ! effects ( any *anges ( temp]ature & pressure t c\ld occur4 ,a deliv]y tube may be connect$ to ,h & fill$ ) m]cury1 by clos+ ,e & rais+ ! m]cury res]voir4 ,all air be+ 9 t way expell$ f ! deliv]y tube1 & ! supply ( m]cury cut (f by clamp+ ! tube f ! res]voir1 oxyg5 c be deliv]$ f ! tube by op5+ ,e1 :5 x w s5d =w>d ! m]cury1 & pass into a tube plac$ to receive x )\t any risk ( air be+ d]iv$ f ! deliv]y tube4 ,illu/ration3 ,,fig4 #ce4 7#b47 ,gimm+ham's ,vacuum ,tap1#ae %[n 9 ,fig4 #ce1 consi/s ( ?ree p>ts4 ,a tube ,a is gr\nd to fit ! neck ( ,b4 ,b is clos$ at its l[] end1 & has a hole d drill$ ?r\gh x2 :5 ,b is fitt$ to ,c1 d c be made to co9cide ) ! slit e4 ,:5 ,a1 ,b1 ,c are fitt$ toge!r1 if d meet e1 !re is communication betwe5 any vessels atta*$ to ,a & any o!r vessel atta*$ to ,c1 entrance ( ext]nal air be+ prev5t$ by m]cury be+ plac$ 9 ! cups ( ,c & ,b4 ,! tap may be op5$ & clos$ at pleasure by rotat+ ,b4 #ae ,f ,proce$+s ( ,royal ,society1 vol4 ,,xxv4 p4 #cif4 ,if ,a has to be remov$1 ,c may be conv]t$ into a m]cury jo9t pro tem4 by lett+ a little m]cury f ! upp] cup fall into ! tube & cov] d1 ! tap be+ clos$4 ,?is m]cury mu/ be remov$ by a f9e pipette 9 ord] to use ! tap aga94 ,x %\ld be not$1 h[ev]1 t ?\gh ext]nal air _c ent] by way ( ! gr\nd glass jo9ts1 !re is no absolute protection aga9/ ! passage ( air betwe5 ,a & ,c1 or vessels jo9$ to ,a & ,c1 ev5 :5 ! tap is clos$4 ,! passage ( air f ,a to ,c dep5ds ^u ! gr9d+ & lubrication ( ! jo9t at ,c4 ,lubricat+ ,taps4--,= g5]al purposes res9 c]ate answ]s v well4 ,9 special cases burnt india-rubb]1 or a mixture ( burnt india-rubb] & vasel9e w answ] well1 or vasel9e may be us$ alone4 ,sulphuric acid & glyc]9e are too fluid4 ,:5 a lubricant is want$ t w )/& ! action ( e!r1 ! tap may be lubricat$ by spr9kl+ phosphorus p5toxide ^u x1 & expos+ x to air till ! oxide becomes gummy4 ,! jo9t mu/ !n be protect$ f ! fur!r action ( ! air if possible4 ,= example1 if a safety tap be us$ ! cup may be fill$ ) m]cury4 ,air-,traps4--,9 ,fig4 #cc1 p4 #ff1 an air-trap 7,j7 is %[n4 ,an air-trap is a device = prev5t+ ! m]cury suppli$ to ,spr5gel pumps1 etc41 f c>ry+ air into spaces t are exhau/$1 or are = any reason to be kept free f air4 ,figs4 #cf & #cg give examples ( air-traps4 ,9 ! simpl] ( ! two 7,fig4 #cf7 m]cury fl[+ upw>ds f ,c t may c>ry bubbles ( air ) x passes ?r\gh ! bulb ,a1 :i* is fill$ ) m]cury be=e use4#af ,any air :i* accompanies ! m]cury w collect at a1 ! m]cury w fl[ on ?r\gh b4 ,s long z ! level ( ! m]cury 9 ,a is above b1 ! trap rema9s effective4 #af ,?is may be done by clamp+ ! tube :i* supplies m]cury bel[ ,c1 exhau/+ ,a1 & !n op5+ ! clamp$ tube & all[+ ! m]cury to rise4 ,illu/ration3 ,,fig4 #cf4 ,illu/ration3 ,,fig4 #cg4 ,9 ! trap %[n by ,fig4 #cg1 ! tube d1 :i* corresponds to b 9 ,fig4 #cf1 is protect$ at its end by ! cup ,e4 ,e prev5ts ! direct passage ( m9ute bubbles ( air ?r\gh d4 ,?is trap1 l ! o!r1 mu/ be fill$ ) m]cury be=e x is us$1 & x w !n rema9 effective = "s "t4 ,,*apt] ,v4 ,,graduat+ ,,& ,,calibrat+ ,,glass ,,app>atus4 ,al?\gh ! subjects to :i* ?is conclud+ *apt] is devot$ d n1 prop]ly speak+1 consi/ ( op]ations 9 glass-bl[+1 !y are s alli$ to ! subject1 & ( su* great importance1 t ,i ?9k a brief acc\nt ( !m may advantage\sly be includ$4 ,graduat+ ,tubes1 etc4--,x 0 =m]ly ! cu/om to graduate ! app>atus int5d$ = use 9 quantitative "w into p>ts ( equal capacity2 = example1 into cubic c5timetres & fractions ( cubic c5timetres4 ,= ! op]ations ( volumetric analysis by liquids ?is is /ill done4 ,b = mo/ purposes x is bett] to employ a scale ( equal divisions by l5g?1 usually ( millimetres1 & to det]m9e ! relative values ( ! divisions aft]w>ds1 z describ$ "u calibration4 ,x r>ely happ5s t ! tube ( :i* a burette or eudiomet] is made has equal divisions ( its l5g? ( exactly equal capacities ?r\gh\t its entire l5g?1 & inde$1 ev5 = ord9>y volumetric "w1 no burette %\ld be employ$ be=e its accuracy has be5 v]ifi$4 ,an excell5t me?od = graduat+ glass tubes by h&#ag has be5 describ$ 9 ,watts's ,diction>y ( ,*emi/ry1 & else:]e4 ,ano!r excell5t plan1 :i* ,i h p]mission to describe1 has be5 employ$ by ,pr(essor ,w4 ,ramsay4 ,x w be suffici5t if ,i expla9 its application to ! op]ation ( graduat+ a tube or /rip ( glass 9 millimetre divisions4 #ag ,orig9ally sugge/$ by ,buns54 ,! app>atus requir$ consi/s ( a /&>d metre measure1#ah divid$ into millimetres along ea* ( its edges1 ) c5timetre divisions betwe5 !m1 a rul] adapt$ to ! /&>d metre1 z subsequ5tly expla9$1 & a /yle ) a f9e po9t = m>k+ wax$ surfaces4 #ah ,su* measures c be obta9$ ( /eel = ab\t fifte5 %ill+s ea*4 ,!y are made by ,mr4 ,*e/]man ( ,%effield4 ,!y c be obta9$ also f o!r mak]s ( philosophical in/rum5ts1 at prices dep5d+ ^u _! delicacy4 ,^? ( ! greate/ accuracy are some:at co/ly4 ,illu/ration3 ,,fig4 #ch4 ,fig4 #ch repres5ts ! /&>d measure1 & ! rul]4 ,at ,,aa are ! millimetre divisions on ! edges ( ! measure1 ! long] transv]se l9es at ,,bb are plac$ at int]vals ( five millimetres & ( c5timetres4 ,! rul] is 9 ! =m ( a "r-angl$ triangle2 x is %[n1 by ! dott$ l9es1 9 position on ! /&>d metre measure at ,i2 & aga91 ) its "u surface upw>ds1 9 ! small] figure at #b4 ,x consi/s ( a p]fectly flat %eet ( metal1 ab\t t5 c5timetres 9 l5g? f ,c to ,c1 suffici5tly ?ick to be rigid1 & has a l$ge1 ,,dd 9 ea* figure1 :i* is press$ aga9/ ! side ( ! measure :5 us+ x1 to ensure t ! successive positions ( ! edge 7,,ll7 %all be p>allel to ea* o!r4 ,at ,,gg are two small holes1 into :i* fit small screws ) f9e po9ts4 ,^! mu/ be 9 a l9e p>allel to ! edge 7,,ll71 s t :5 ! rul] is 9 position on ! scale1 ! po9ts ( ! two screws1 :i* project slightly1 %all fall into correspond+ cuts on ! divid$ scales 7,,aa74 ,to graduate a /rip ( glass1 or a glass tube 7,,hh71 ! surface to be m>k$ mu/ fir/ be coat$ ) wax1 :i* %\ld be mix$ ) a little turp5t9e1 & be appli$ to ! surface ( ! glass1 previ\sly made w>m & dry1 by means ( a f9e bru%1 s z to completely cov] x ) a ?91 closely-adh]5t1 & ev5ly-di/ribut$ coat ( wax1 :i* mu/ be all[$ to cool4 ,fix ,,hh firmly on a table1 & fix ! /&>d measure by ! side ( ,,hh4 ,if ! ?ickness ( ,,hh be ab\t equal to1 b n great] ?an t ( ! /&>d measure1 ?is may be done by l>ge draw+-p9s4 ,if1 h[ev]1 a l>ge tube or ?ick %eet ( glass is to be graduat$1 fix x 9 position by two /rips ( wood screw$ to ! table on ea* side ( x4 ,"o ( ^! wood5 /rips1 on :i* ! measure may be plac$1 may be ab\t z broad z ! /&>d measure1 & ( su* ?ickness t :5 ! measure lies ^u x beside ! tube to be graduat$1 ! rul]1 :5 mov$ along ! measure1 w move freely above ! tube1 b w n be elevat$ m ?an is necess>y to secure free movem5t4 ,! second /rip ( wood may be n>r[]1 & ( ! same ?ickness z ! broad] piece on :i* ! /&>d measure re/s4 ,9 any case1 let ! /&>d measure & ! object to be graduat$ be v firmly secur$ 9 _! places4 ,br+ ! rul] into position at any desir$ "p ( ! tube by plac+ ! po9ts ( ! screws 7,,gg7 9 correspond+ divisions ( ! scales 7,,aa74 ,) ! /yle1 :i* may be a ne$le m\nt$ 9 a h&le1 make a scrat* 9 ! wax along ! edge ( ! rul] at ,f1 move ! rul] s t ! screws re/ 9 ! next divisions1 & repeat ! op]ation till ! requir$ numb] ( l9es has be5 rul$4 ,long] m>ks may be made at int]vals ( five & t5 millimetres4 ,great c>e mu/ be tak5 to hold ! ne$le p]p5dicul>ly1 & to press x /eadily aga9/ ! edge 7,,ll7 ( ! rul] 9 scrat*+ ! divisions4#ai ,! l5g? ( ! l9es m>k+ ! millimetre divisions %\ld n be too long2 ab\t #a mm4 is a good l5g?4 ,if !y are long] ?an ?is1 ! app>5t di/ance betwe5 !m is dim9i%$1 & x is less easy to read fractions ( millimetres4 ,be=e remov+ ! scale to et* ! glass1 c>efully exam9e x to see t no mi/akes h be5 made4 ,if x is f\nd t any l9es h be5 omitt$1 or t long l9es h be5 scrat*$ 9 ! place ( %ort ones1 remelt ! wax by means ( a heat$ wire1 & make new m>ks4 ,f9ally1 m>k ! numb]s on ! scale ) a ne$le-po9t1 or bett]1 ) a f9e /eel p54 #ai ,to avoid v>iations ( ! position 9 :i* ! ne$le is held :5 m>k+ ! divisions1 ! edge 7,,ll7 %\ld n be bevell$2 & an upright support may be plac$ ^u ! rul]1 ) a r+ ?r\gh :i* ! h&le ( ! ne$le passes1 !reby secur+ t ! angle =m$ by ! ne$le & surface ( ! rul] is con/ant1 & t equal divisions are m>k$4 ,! m>ks on ! wax %\ld cut ?r\gh x4 ,:5 !y are satisfactory1 !y may be et*$ by "o ( ! foll[+ processes3-- 7#a47 ,by moi/5+ "s cotton wool1 ti$ to a /ick1 ) solution ( hydr(luoric acid1 & g5tly rubb+ ?is ov] ! scrat*$ surface = a m9ute or s2 !n wa%+ away ! acid ) wat]1 & clean+ (f ! wax4 ,?is is ! simple/ me?od1 b ! m>ks made are g5]ally transp>5t1 & !re=e n v easy to read4 ,! simplicity ( ?is me?od is a great recomm5dation1 h[ev]4 7#b47 ,expose ! tube to ! fumes ( hydr(luoric acid g5]at$ f a mixture ( p[d]$ fluor-sp> & /rong sulphuric acid1 9 a lead5 tr\gh4 ,! m>ks produc$ 9 ?is way are usually opaque1 & are !re=e v visible1 & easily read4 ,aft] ! above detail$ acc\nt x w only be necess>y to give an outl9e ( ! o!r process ( graduat+ tubes4 ,illu/ration3 ,,fig4 #ci4 ,! /&>d scale to be copi$1 ,a1 :i* may 9 ?is case be ano!r graduat$ tube1 or ev5 a pap] scale1 & ! object to be rul$1 ,b1 are securely fix$1 end to end1 a little di/ance ap>t1 9 a groove made 9 a bo>d or 9 ! top ( a table4 ,a /iff b> ( wood1 ,c1 has a po9t fix$ at ,d1 & a knife edge at ,e1 ,d is plac$ 9 any division ( ,a1 ,c is held firmly at ,e & ,d1 & a cut is made by ! knife ?r\gh ! wax on ,b1 ! po9t ,d is !n mov$ into ! next division1 & ! op]ation is repeat$4 ,to regulate ! l5g? & position ( ! cuts1 ,b is usually held 9 position by two %eets ( brass project+ ov] ! edges ( ! groove 9 :i* x lies2 ! metal %eets h not*es cut into !m at ! int]vals at :i* long] m>ks are to be made4 ,:5 ! scale is complet$1 ! equality ( ! divisions 9 v>i\s p>ts ( x may be1 to "s ext5t1 v]ifi$ z foll[s3--,adju/ a compass s t its po9ts fall into two divisions #e1 #aj1 or #bj mm4 ap>t4 ,!n apply ! po9ts ( ! compass to v>i\s p>ts ( ! scale4 ,9 e "p ! l5g? ( a giv5 numb] ( divisions %\ld be exactly ! same4 ,! individual divisions %\ld also be c>efully inspect$ by ! eye2 !y %\ld be s5sibly equal4 ,if badly rul$1 long & %ort divisions w be f\nd on ! scale4 ,v (t5 a long & a %ort division w be adjac5t1 & w be ! m easily obs]v$ 9 consequ5ce4 ,to ,divide a ,giv5 ,l9e into ,equal ,p>ts4--,occasionally x is necess>y to divide a l9e ( giv5 l5g? into x equal p>ts4 ,= in/ance1 to divide ! /em ( a !rmomet] f ! freez+-po9t to ! boil+-po9t into "o hundr$ degrees4 ,! foll[+ outl9e w expla9 h[ a l9e may be s divid$4 ,suppose ! l9e ,,ab 7,fig4 #dj7 is to be divid$ into n9e equal p>ts4 ,adju/ a h+$ rule s t ! po9ts ,a & ,b co9cide ) ! inside edges ( ! limbs1 "o ( !m1 ,a1 be+ at ! n9? division 7e4g4 ! n9? in*7 ( ,,ce4 ,!n if l9es p>allel to ,,ed be drawn f ea* division ( ! scale to meet ,,ab1 ,,ab w be divid$ into n9e equal p>ts4 ,illu/ration3 ,,fig4 #dj4 ,a v conv5i5t & simple arrangem5t on ?is pr9ciple = divid+ a l9e into any numb] ( equal p>ts ) consid]able accuracy1 is describ$ by ,miss ,s4 ,m>ks 9 ! ,proce$+s ( ! ,physical ,society1 ,july #ahhe4bj ,"o limb ( a h+$ rule ,d is made to slide ^u a pla9 rule fix$ to x2 ! pla9 rule c>ries ne$les on its "u surface :i* hold ! pap] 9 position4 ,! position ( ! divid$ rule & l9e to be divid$ be+ adju/$1 ! h+$ rule is g5tly pu%$ =w>ds1 z indicat$ by ! arr[ 9 ,fig4 #dj1 till division eight co9cides ) ! l9e ,,ab4 ,a m>k is made at ! po9t ( co9cid5ce1 & division sev5 on ! scale is simil>ly br\ght to ! l9e ,,ab1 & s on4 ,! inn] edge ( ,,ec %\ld h ! divisions m>k$ ^u x1 t _! co9cid5ce ) ,,ab maybe m accurately not$4 ,! jo9t ,e mu/ be a v /iff "o4 #bj ,s9ce ?is 0 pr9t$ ,i h obs]v$ t ! above me?od is n id5tical ) t describ$ by ,miss ,m>ks1 b = ord9>y purposes ,i d n ?9k x w be f\nd to be inf]ior4 ,a l9e drawn ( giv5 l5g? or a piece ( pap] may be divid$ into any giv5 numb] ( equal p>ts1 & w !n s]ve z ! scale ,a ( ,fig4 #ci1 p4 #gd1 ! !rmomet] or o!r object to be graduat$ tak+ ! place ( ,b4 ,scales c>efully divid$ accord+ to any ( ! me?ods describ$ w be fairly accurate if tru/wor?y in/rum5ts h be5 employ$ z /&>ds4 ,x w be f\nd possible :5 obs]v+ ! volume ( a gas ov] m]cury1 or ! height ( a column ( m]cury 9 a tube1 to measure diff]5ces ( "o-six? to "o-eigh? ( a millimetre ) a consid]able degree ( accuracy4 ,to obta9 m delicate measurem5ts a v]ni]#ba mu/ be employ$4 #ba ,= ! nature & use ( ! v]ni]1 a treatise on ,physics or ,physical ,measurem5ts may be consult$4 ,to ,calibrate ,app>atus4--,! glass tubes ( :i* graduat$ app>atus is made are1 z already /at$1 v r>ely truly cyl9drical ?r\gh\t _! entire l5g?s4 ,x foll[s t ! capacities ( equal l5g?s ( a tube w usually be unequal1 & !re=e x is necess>y to asc]ta9 by exp]im5t ! true values ( equal l9e> divisions ( a tube at v>i\s p>ts ( x4 ,a burette may be calibrat$ by fill+ x ) di/ill$ wat]1 draw+ (f portions1 say ( #e c4c4 9 succession1 into a weigh+ bottle ( kn[n weight1 & weigh+ !m4 ,great c>e mu/ be tak5 9 read+ ! level ( ! liquid at ea* obs]vation4 ,! be/ plan is to hold a piece ( :ite pap] beh9d ! burette1 & to read f ! l[] edge ( ! black l9e t w be se54 ,ea* op]ation %\ld be repeat$ two or ?ree times1 & ! mean ( ! results1 :i* %\ld diff] b slightly1 may be tak5 z ! value ( ! portion ( ! tube "u exam9ation4 ,if ! weights ( wat] deliv]$ f equal divisions ( ! tube are f\nd to be equal1 ! burette is an accurate "o1 b if1 z is m likely1 diff]5t values are obta9$1 a table ( results %\ld be drawn up 9 ! laboratory book %[+ ! volume ( liquid deliv]$ f ea* portion ( ! tube exam9$4 ,& subsequ5tly :5 ! burette is us$1 ! volumes read f ! scale on ! burette mu/ be correct$4 ,suppose1 = example1 t a burette deliv]$ ! foll[+ weights ( wat] f ea* division ( #e c4c4 respectively3-- ,c4,c4 ,grams4 #j to #e gave #d4ij #e #aj #d4ia #aj #ae #d4ib #ae #bj #d4ic #bj #be #d4id #be #cj #d4ie #cj #ce #d4if #ce #dj #d4ig #dj #de #d4ih #de #ej #d4ii & t 9 two exp]im5ts #bj c4c4 & #de c4c4 respectively ( a liquid re-ag5t 7 employ$4 ,! true volumes calculat$ f ! table w\ld be z #ai4ff to #dd4df4 ,if ! temp]ature rema9$ con/ant ?r\gh\t ! above s]ies ( exp]im5ts1 & if ! temp]ature select$ 7 #d deg4 ,c41 ! weights ( wat] f\nd1 tak5 9 grams1 give ! volumes 9 cubic c5timetres1 = "o gram ( wat] at #d deg4 ,c4 has a volume ( "o cubic c5timetre4 ,if ! temp]ature at :i* ! exp]im5ts 7 made 0 o!r ?an #d deg4 ,c41 & if great accuracy be desir$1 a table ( d5sities mu/ be consult$1 ) ! help ( :i* ! volume ( any weight ( wat] at a kn[n temp]ature c be readily calculat$4 ,pipettes :i* are to be us$ z measur+ in/rum5ts %\ld also h ! relation "o to ano!r ( ! volumes ( liquid :i* !y deliv] det]m9$1 & also ! proportions ^! be> to ! values f\nd = ! divisions ( ! burettes 9 conjunction ) :i* !y w be employ$4 ,to ,calibrate ,tubes = ,measur+ ,gases4--,prep>e a small glass tube seal$ at "o end & gr\nd at ! o!r to a plate ( glass4 ,! tube %\ld hold ab\t z mu* m]cury z w fill #aj mm4 divisions ( ! graduat$ tube4 ,fill ?is tube ) m]cury1 remov+ all bubbles ( air t adh]e to ! sides by clos+ ! op5 end ( ! tube ) ! ?umb1 & wa%+ !m away ) a l>ge air-bubble left = ! purpose4 ,if any p]si/5tly rema91 remove !m by means ( a f9e piece ( bone or wood4 ,!n completely fill ! tube ) m]cury1 remov+ any bubbles t may be introduc$ 9 ! op]ation1 & remove ! excess ( m]cury by plac+ ! gr\nd-glass plate on ! m\? ( ! tube1 & press+ x s z to =ce out all excess ( m]cury betwe5 ! two surfaces4 ,clean ! outside ( ! tube1 & place x on a small /& 7?is may be a small wide-m\!d glass bottle71 ) :i* x has be5 previ\sly weigh$ :5 empty1 & re-weigh4 ,repeat ?is op]ation sev]al times4 ,f ! mean ( ! results1 :i* %\ld diff] "o f ano!r b v slightly1 ! capacity ( ! tube c be calculat$4 ,! pure/ m]cury obta9able %\ld be us$4 ,s9ce ! d5sity ( pure m]cury at #j deg4 ,c4 is #ac4eif1 ! weight ( m]cury requir$ to fill ! tube at #j deg4 ,c41 tak5 9 grams1 :5 divid$ by #ac4eif1 w give ! capacity ( ! tube at #j deg4 ,c4 9 cubic c5timetres4 ,if ! exp]im5t be n made at #j deg4 ,c41 & if a v exact det]m9ation ( ! capacity ( ! tube be requir$1 ! d5sity ( m]cury mu/ be correct$ = expansion or contraction4 ,hav+ n[ a vessel ( kn[n capacity1 x c be employ$ = asc]ta9+ ! capacities ( ! divisions ( a graduat$ tube 9 ! foll[+ mann]3--,! graduat$ tube is fix$ p]p5dicul>ly1 m\? upw>ds1 9 a secure position4 ,! small tube ( kn[n capacity is fill$ ) m]cury z previ\sly describ$1 & its cont5ts are transf]r$ to ! divid$ tube4 ,! numb] ( divisions :i* ! kn[n volume ( m]cury occupies is not$ aft] all air-bubbles h be5 remov$4 ,?is process is repeat$ until ! divid$ tube is fill$4 ,a table ( results is prep>$1 %[+ ! numb] ( divisions occupi$ by ea* kn[n volume ( m]cury introduc$4 ,9 subsequ5tly us+ ! tube ! volumes ( ! gases measur$ 9 x mu/ be asc]ta9$ f ! table ( values ?us prep>$4 ,9 obs]v+ ! level ( ! m]cury1 unless a ca!tomet] is available1 a slip ( mirror %\ld be held beh9d ! m]cury close to ! tube1 9 su* a position t ! pupil :i* is visible on ! look+-glass is divid$ into two p>ts by ! surface ( ! m]cury4 ,a correction mu/ be introduc$ = ! error caus$ by ! m5iscus ( ! m]cury4 ,z ! clos$ end ( ! tube 0 d[nw>ds :5 ea* measur$ volume ( m]cury 0 introduc$1 & z ! surface ( m]cury is convex1 ! volume ( m]cury 9 ! tube :5 x is fill$ to any division l 7,fig4 #da7 is repres5t$ by ,a ( #a4 ,b 9 subsequ5tly measur+ a gas ov] m]cury 9 ! same tube1 :5 ! m]cury /&s at ! same division l1 ! volume ( ! gas w be z repres5t$ by ,b ( #b1 :i* is evid5tly some:at great] ?an ,a4 ,?is w be se5 /ill m cle>ly 9 #c1 :]e a repres5ts ! b\nd>y ( ! m]cury1 & b ! b\nd>y ( ! air1 :5 ! tube is fill$ to ! m>k l ) m]cury or a gas ov] m]cury respectively4 ,illu/ration3 ,,fig4 #da4 ,x is pla9 t :5 ! level ( ! m]cury 9 measur+ a gas is read at l1 ! volume ( ! gas is great] ?an ! volume ( ! m]cury record$1 by twice ! diff]5ce betwe5 ! volume ,a ( m]cury measur$1 & t :i* w\ld fill ! tube to ! level l1 if its surface 7 plane4 ,! usual mode ( f9d+ ! true volume ( a gas collect$ ov] m]cury is z foll[s3-- ,place ! graduat$ tube m\? upw>ds1 introduce "s m]cury1 &1 aft] remov+ all bubbles1 note ! division at :i* x /&s4 ,!n add a few drops ( solution ( m]curic *loride2 ! surface ( ! m]cury w become level1 read & record its new position4 ,!n1 9 any measurem5t1 hav+ obs]v$ t ! m]cury /&s at n divisions ( ! tube1 add twice ! diff]5ce betwe5 ! two positions ( ! m]cury to n1 & asc]ta9 ! volume :i* corresponds to ?is read+ f ! table ( capacities4 ,to ,calibrate ! ,tube ( a ,!rmomet]4--,deta* a ?read ( m]cury f half an in* to "o in* 9 l5g? f ! body ( ! m]cury4 ,move x f po9t to po9t ?r\gh\t ! l5g? ( ! tube1 & note its l5g? 9 ea* position4 ,if 9 "o "p x occupies a l5g? ( tube correspond+ to eight degrees1 & at ano!r only sev5 degrees1 !n at ! =m] po9t ! value ( ea* division is only sev5-eigh?s ( ^? at ! latt] position4 ,f ! results obta9$1 a table ( corrections = ! !rmomet] %\ld be prep>$4 ,x is sometimes necess>y to jo9 soda glass to lead glass4 ,9 ?is case ! edge ( ! lead glass tube may be bord]$ ) :ite enamel be=e mak+ ! jo9t4 ,en\gh enamel mu/ be us$ to prev5t ! lead & soda glasses f m+l+ at any po9t4 ,! enamel is easily r$uc$1 & mu/ be heat$ 9 ! oxidis+ flame4 ,dr4 ,eb]t recomm5ds ,v]re d'urane = ?is purpose4 ,x is suppli$ by ,h]r ,goetze ( ,leipzig 7,liebig/rasse74 ,,*apt] ,,vi4 ,,glass ,,tub+4 ,! diagrams giv5 bel[ %[ ! sizes & ?ickness ( ! glass tubes mo/ frequ5tly requir$4 ,9 ord]+1 ! numb]s ( ^! diagrams may be quot$1 or ! exact dim5sions desir$ may be /at$4 ,glass tubes are usually sold by weight1 & !re=e ! weight ( tube ( ea* size t is wi%$ = %\ld be indicat$1 & also :e!r x is to be ( lead or soda glass4 ,illu/ration ,illu/ration ,,*apt] ,,vii4 ,,vitre\s ,,silica4 ,introductory4--,vitre\s ,silica 0 made 9 f9e ?reads by ,m4 ,gaud9 9 #ahci1bb & small tubes ( x 7 made 9 #ahfi by ,m4 ,a4 ,gauti]1 b its rem>kable qualities 7 n really recognis$ till #ahhi1 :5 ,pr(essor ,c4 ,v4 ,boys r$iscov]$ ! process ( mak+ small pieces ( app>atus ( ?is sub/ance1 & us$ ! torsion ( qu>tz fibres = measur+ small =ces4 ,m rec5tly ! au?or ( ?is book has devis$ a process = prev5t+ ! spl9t]+ ( qu>tz :i* gave s mu* tr\ble to ! e>li] work]s1 & jo9tly ) ,mr4 ,h4 ,g4 ,lacell1 has produc$ a v>iety ( app>atus ( mu* l>g] dim5sions ?an _h be5 attempt$ previ\sly4 ,at ! "t ( writ+ we c produce by ! processes describ$ 9 ! foll[+ pages tubes #a to #a4e cm4 9 diamet] & ab\t #gej cm4 9 l5g?1 globes or flasks capable ( conta9+ ab\t #ej cc41 masses ( vitre\s silica weigh+ #ajj grams or m1 & a v>iety ( o!r app>atus4 #bb ,a brief summ>y ( ! hi/ory ( ?is subject w be f\nd 9 ,nature1 ,vol4 #fb1 & 9 ! ,proce$+s ( ! ,royal ,in/itution1 #aija4 ,prop]ties ( ,vitre\s ,silica4--,= ! conv5i5ce ( ^? :o are n famili> ) ! lit]ature ( ?is subject1 ,i may comm5ce ?is *apt] ) a brief acc\nt ( ! prop]ties & applications ( vitre\s silica1 z f> z !y are at pres5t asc]ta9$4 ,vitre\s silica is less h>d ?an *alc$ony1 b h>d] ?an felsp>4 ,tubes & rods ( x c be cut ) a file or ) a piece ( %>p5$ & h>d5$ /eel1 & c aft]w>ds be brok5 l simil> articles ( glass4 ,its conduct+ p[] is l[1 & ,mr4 ,boys has %[n t f9e fibres ( silica insulate rem>kably well1 ev5 9 an atmosph]e saturat$ ) moi/ure4 ,! insulat+ qualities ( tubes or rods ( l>ge cross sections h n yet be5 fully te/$2 "o w\ld expect !m to give good results provid$ t !y are kept scrupul\sly clean4 ,a silica rod :i* _h be5 mu* h&l$ w\ld probably insulate no bett] ?an "o ( glass 9 a simil> condition4 ,! d5sity ( vitre\s silica is v ne> to t ( ord9>y amorph\s silica4 ,9 ! case ( a small rod n absolutely free f m9ute bubbles x 0 f\nd to be #b4ba4 ,vitre\s silica is optically inactive1 :5 homog5e\s1 & is highly transp>5t to ultraviolet radiations4 ,! melt+ po9t ( vitre\s silica _c be def9itely /at$4 ,x is pla/ic ov] a consid]able range ( temp]ature4 ,pr(essor ,call5d> has succe$$ 9 measur+ ! rate ( contraction ( f9e rods 9 cool+ f #abjj deg4 to #aejj deg4 ,c41 s t its pla/icity mu/ be v slight bel[ ! latt] temp]ature4 ,if a plat9um wire emb$d$ 9 a ?ick silica tube be heat$ f )\t by an oxy-hydrog5 flame ! metal may be melt$ at temp]atures at :i* ! silica tube w reta9 its =m = a mod]ate l5g? ( "t1 b silica s(t5s to a m>k$ ext5t at temp]atures a little above ! melt+ po9t ( plat9um4 ,x has be5 obs]v$ by ,boys1 ,call5d>1 & o!rs t f9e rods ( silica1 & also ! s-call$ qu>tz fibres1 are apt to become brittle aft] !y h be5 heat$ to r$ness4 ,b ,i h n obs]v$ ?is defect 9 ! case ( m massive objects1 su* z ?ick rods or tubes2 & z ,i h repeat$ly obs]v$ t m]e traces ( basic matt]1 su* z may be convey$ by contact ) ! h&1 s]i\sly injure ! surface ( silica1 & h f\nd t silica quickly becomes rott5 :5 x is heat$ to ab\t #ajjj deg4 9 contact ) an infusible base su* z lime1 ,i am dispos$ to ascribe ! above-m5tion$ ph5om5on to *emical r ?an to purely physical causes4#bc ,x is c]ta91 h[ev]1 t silica app>atus mu/ nev] be too /rongly heat$ 9 contact ) basic sub/ances4 ,silica is easily attack$ by alkalis & by lime1 less readily by copp] oxide1 & /ill less by iron oxide4 #bc ,9 a rec5t communication ,pr(essor ,call5d> tells me t ! devitrification comm5ces at ! outside & is ha/5$ by p>ticles ( =eign matt]4 ,! rate ( expansion ( vitre\s silica has be5 /udi$ by ,h4 le ,*ateli]1 & m rec5tly by ,call5d>4 ,! =m] f\nd its mean coeffici5t ( expansion to be #j4jjjjjjg betwe5 #j deg4 & #ajjjj deg41#bd & t x contract$ :5 heat$ above #gjj deg44 #bd ,! silica blocks us$ 7 prep>$ by fusion 9 an electric furnace2 x is !re=e probable t !y 7 n q pure4 ,pr(essor ,call5d> us$ rods ( silica prep>$ by ! au?or f ,brazil cry/al2 ^! 7 drawn 9 ! oxy-gas flame & _h nev] be5 heat$ 9 contact ) solid =eign matt]1 s t !y consi/$1 presumably1 ( v pure silica4 ,8 results diff] 9 "s respects f ^? obta9$ by ,le ,*ateli]1 = he f9ds ! mean coeffici5t ( expansion to be only #j4jjjjjjei1 i4e4 ab\t "o sev5te5? z great z t ( plat9um4 ,call5d> f\nd ! rods ( silica exp&$ v regul>ly up to #ajjj deg4 b less regul>ly above t temp]ature4 ,above #abjj deg4 !y contract$ :5 heat$4 ,! behavi\r ( vitre\s silica "u sudd5 *anges ( temp]ature is mo/ rem>kable4 ,l>ge masses ( x may be plung$ sudd5ly :5 cold into ! oxy-gas flame1 & tubes or rods at a :ite heat may be ?ru/ into cold wat]1 or ev5 into liquid air1 ) impunity4 ,z a consequ5ce ( ?is1 x is 9 "o respect mu* m easily work$ 9 ! flame ?an any =m ( glass4 ,difficult jo9ts c be ?ru/ sudd5ly into ! flame1 or remov$ f x1 at any /age1 & !y may be heat$ unequally 9 diff]5t p>ts ) impunity4 ,x is safe to say t jo9ts1 etc41 9 silica nev] crack :il/ "o is mak+ !m nor dur+ ! subsequ5t cool+4 ,!y may be set aside 9 an unf9i%$ /ate & tak5 up aga9 )\t any precautions4 ,!re=e x is possible = an amateur to con/ruct app>atus 9 silica :i* he w\ld be q unable to produce f glass4 ,! behavi\r ( vitre\s silica ) solv5ts has n yet be5 fully inve/igat$1 b ,mr4 ,h4 ,g4 ,lacell has ?is subject 9 h&4 ,if x behaves l ! o!r =ms ( anhydr\s silica x w )/& ! action ( all acids except hydr(luoric acid4 ,x is1 ( c\rse1 v readily act$ ^u by solutions ( alkalis & alkal9e salts4 ,z reg>ds ! use ( silica 9 exp]im5ts ) gases1 x mu/ be rem>k$ t vitre\s silica1 l plat9um1 is slightly p]meable to hydrog5 :5 /rongly heat$4 ,"o consequ5ce ( ?is is t traces ( moi/ure are almo/ always to be f\nd inside rec5tly-made silica tubes & bulbs1 h[ev] c>efully we may h dri$ ! air =c$ into !m dur+ ! process ( con/ruction4 ,ow+ to ! v l[ coeffici5t ( expansion ( silica1 x is n possible to seal plat9um wires into silica tubes4 ,nor c plat9um be cem5t$ into ! silica by means ( ars5ic enamel1 nor by any ( ! s(t] glasses us$ = su* purposes4 ,i h come ne> to success by us+ kaol91 b ! results ) ?is mat]ial d n af=d a real solution ( ! problem1 ?\gh !y may p]haps po9t to a hopeful l9e ( attack4 ,possibly plat9um wires might be sold]$ into ! tubes 7see ,laboratory ,arts1 ,r4 ,?relfall71 b ?is also is unc]ta94 ,! process ( prep>+ silica tubes1 etc41 f ,lumps ( ,brazil ,cry/al may be describ$ conv5i5tly "u ! foll[+ head+s4 ,i describe ! v>i\s processes fully 9 ^! pages1 z ^? :o are int]e/$ 9 ! matt] w probably wi% to try e "p ( ! process 9 ! fir/ in/ance4 ,b ,i may say t 9 practice ,i ?9k almo/ e "o w f9d x advantage\s to />t ) pur*as$ silica tubes1 j z a glass-work] />ts ) a supply ( pur*as$ glass tubes4 ,! manufactur] c obta9 8 oxyg5 at a l[] price ?an ! retail pur*as]1 & a workman :o gives mu* "t to su* "w c turn out silica tube s mu* m quickly ?an an amateur1 t ,i ?9k x w be f\nd t bo? "t & money c be sav$ by pur*as+ ! tube4 ,at ! same "t ! beg9n] w f9d x wor? :ile to le>n & practise ea* /age ( ! process at fir/1 z e "p ( ! "w describ$ may be useful 9 ! production ( f9i%$ app>atus f silica tubes4 ,?is be+ s1 ,i am glad to be able to add t a lead+ firm ( deal]s 9 app>atus#be has comm5c$ mak+ silica goods on a comm]cial scale1 s t ! new mat]ial is n[ available = all ^? :o ne$ x or wi% to exam9e its prop]ties4 #be ,messrs4 ,baird & ,tatlock4 ,prep>+ non-spl9t]+ ,silica f ,brazil ,pebble4--,! be/ v>iety ( native ,silica is ,brazil ,pebble1 :i* may be obta9$ 9 *ips or l>g] masses4 ,^! %\ld be ?or\ghly clean$1 heat$ 9 boil+ wat]1 & dropp$ into cold wat]1 ! treatm5t be+ repeat$ till ! masses h crack$ to su* an ext5t t !y may be brok5 easily by bl[s f a clean /eel pe/le or hamm]4 ,! fragm5ts ?us produc$ mu/ be h&-pick$1 & ^? :i* are n p]fectly free f =eign matt] %\ld be reject$4 ,! pure & transp>5t pieces mu/ !n be heat$ to a yell[-r$ heat 9 a cov]$ plat9um di% 9 a muffle or rev]b]atory furnace & quickly plung$ into a deep clean vessel conta9+ clean di/ill$ wat]2 ?is process be+ repeat$1 if necess>y1 till ! product consi/s ( semi-opaque friable masses1 v mu* l a :ite enamel 9 appe>ance4 ,aft] ^! h be5 wa%$ ) di/ill$ wat]1 well dra9$ & dri$1 !y may be br\ght into ! hotte/ "p ( an oxy-gas flame safely1 or press$ sudd5ly aga9/ masses ( :ite hot silica )\t any prelim9>y heat+1 su* z is necess>y 9 ! case ( natural qu>tz4 ,qu>tz :i* has n be5 submitt$ to ! above prep>atory process1 spl9t]s on contact ) ! flame to su* an ext5t t v few w\ld c>e to face ! tr\ble & exp5se ( work+ ) s refractory a mat]ial4 ,b aft] ! above treatm5t1 :i* really gives little tr\ble1 all ! difficulties :i* hamp]$ ! pione] work]s 9 silica disappe> z if by magic4 ,app>atus4--,v little special app>atus ne$ be provid$ = work+ ) silica1 b x is absolutely ess5tial to protect ! eyes ) v d>k glasses4 ,^! %\ld be s d>k z to r5d] x a little difficult to "w ) !m at fir/4 ,if long spells ( "w are und]tak51 two pairs ( spectacles %\ld be provid$1 = ! glasses quickly become hot en\gh to cause great inconv5i5ce & ev5 injury to ! eyes4 ,almo/ any ( ! available oxy-gas burn]s may be us$1 b !y v>y consid]ably 9 effici5cy1 & x is economical to obta9 a v effici5t burn]4 ,! 'bl[-?r\gh' burn]s are lea/ satisfactory1 & ,i h long s9ce ab&on$ ! use ( !m4 ,"s ( ! safety 'mix$-gas jets' h an inconv5i5t trick ( burn+-back1 ) %>p explosions1 :i* are highly disconc]t+1 if ! "w be br\ght too ne> ! nozzle ( ! burn]4 ,i h f\nd ! pat5t burn] ( ,mr4 ,jackson 7,br9's ,oxyg5 ,company1 ,man*e/]7 mo/ satisfactory1 & x (f]s ! advantage t sev]al jets c be comb9$ 9 a gr\p easily & inexp5sively = "w on l>ge app>atus4 ,! l>ge ro>+ flames su* z are us$1 ,i und]/&1 = weld+ /eel are v exp5sive1 & n v effici5t = ! "w "h describ$4 ,! me?od ( mak+ ,silica ,tubes4--,be=e comm5c+ to make a tube a supply ( vitre\s silica 9 rods ab\t "o or two millimetres 9 diamet] mu/ be prep>$4 ,to make "o ( ^!1 hold a fragm5t ( ! non-spl9t]+ silica describ$ above 9 ! oxy-gas flame by means ( =ceps tipp$ ) plat9um s z to melt "o ( its corn]s1 press a small fragm5t ( ! same mat]ial aga9/ ! melt$ "p till ! two adh]e & heat x f bel[ upw>ds1#bf till x becomes cle> & vitre\s1 add a ?ird fragm5t 9 a simil> mann]1 !n a f\r?1 & s on till an irregul> rod has be5 =m$4 ,f9ally re-heat ?is rod 9 sections & draw x out :il/ pla/ic into rods or co>se ?reads ( ! desir$ dim5sions4 ,if "o works c>efully ! =ceps d n suff] mu*4 ,i h _h "o pair 9 almo/ con/ant use = sev]al ye>s2 !y h be5 us$ 9 ! tra9+ ( five beg9n]s & are /ill practically un9jur$4 #bf ,?is is to avoid bubbles 9 ! f9i%$ glass4 ,! beg9n] %\ld "w ) a gauge & regulator on ! bottle ( oxyg51 & %\ld wat* ! consumption ( oxyg5 closely4 ,a l>ge exp5diture ( oxyg5 does n by any means necess>ily imply a correspond+ output ( silica1 ev5 by "o :o has ma/]$ ! initial difficulties4 ,:5 a supply ( ! small rods ( vitre\s silica has be5 provid$1 b9d a few ( !m r\nd a rod ( plat9um 7diamet] say1 #a mm47 by means ( plat9um wires at ! two ends & heat ! silica gradually1 beg9n+ at "o end aft] slightly )draw+ ! plat9um core f t end1 till a r\gh tube ab\t f\r or five c5timetres 9 l5g? has be5 =m$4 ,close "o end ( ?is1 exp& x1 by bl[+1 into a small bulb1 atta* a silica rod to ! remote end ( ! bulb1 re-heat ! bulb & draw x out into a f9e tube4 ,bl[ a fre% bulb on "o end ( ?is & aga9 draw x out1 proce$+ 9 ?is way till y h a tube ab\t six or eight c5timetres 9 l5g?4 ,all l>g] tubes & vessels are produc$ by develop+ ?is f9e tube suitably4 ,precautions4--,! foll[+ po9ts mu/ be c>efully kept 9 m9d1 bo? dur+ ! mak+ ( ! fir/ tube & aft]w>ds3-- 7#a7 ,! hotte/ spot 9 ! oxy-gas flame is at a po9t v ne> ! tip ( ! inn] cone ( ! flame1 & silica c be s(t5$ be/ at ?is hot spot4 ,! excell5ce ( a burn] does n dep5d on ! size ( its flame1 s mu* z on ! temp]ature ( its hot spot1 & ! success ( ! work] dep5ds on 8 skill 9 br++ 8 "w exactly to ?is "p ( ! flame4 ,comp>atively l>ge masses ( silica may be s(t5$ 9 a comp>atively small jet if ! hot spot is prop]ly utilis$4 7#b7 ,silica is v apt to exhibit a ph5om5on resembl+ devitrification dur+ work+4 ,x becomes cov]$ ) a :ite incru/ation1 :i* seems to be comp>atively ri* 9 alkali4#bg ,?is incru/ation is v easily remov$ by re-heat+ ! :it5$ surface1 provid$ t ! mat]ial has be5 kept scrupul\sly clean4 ,if ! silica has be5 br\ght into ! flame :5 du/y1 or ev5 aft] mu* contact ) ! h&s ( ! op]ator1 its surface is v apt to be p]man5tly injur$4 ,too mu* att5tion _c be giv5 to cleanl9ess by ! workman4 #bg ,! rock cry/al exhibits a yell[ flame :5 fir/ heat$ 9 ! oxy-gas flame1 & mo/ samples conta9 spectroscopic quantities ( li?ium4 7#c7 ,:5 a heat$ tube or bulb ( silica is to be exp&$ by bl[+1 x is be/ n to remove x f ! flame1 = if t is done x w lose its pla/icity quickly unless x be l>ge4 ,! bett] plan is to move x slightly f ! hot spot into ! surr\nd+ p>ts ( ! flame at ! mom5t ( bl[+4 ,x is be/ to bl[ ! bulb ?r\gh an india-rubb] tube atta*$ to ! op5 end ( ! silica tube4 ,at fir/ "o frequ5tly bur/s ! bulbs :5 do+ ?is1 b holes are easily repair$ by /opp+ !m ) pla/ic silica appli$ by ! s(t5$ end ( a f9e rod ( silica & exp&+ ! lump1 aft] re-heat+ x1 by bl[+4 ,aft] a few h\rs' practice ^! mi%aps gradually become r>e4 ,i f9d x a good plan to int]pose a glass tube pack$ ) granulat$ pota% betwe5 ! m\? & ! silica tube4 ,?is prev5ts ! int]ior ( ! tube f be+ soil$4 ,! purify+ mat]ial mu/ n be pack$ s closely 9 ! tube z to prev5t air f pass+ freely ?r\gh x "u a v l[ pressure4 ,x may be m5tion$ "h t a f9i%$ tube usually conta9s a little moi/ure1 & a recognisable quantity ( nitric p]oxide4 ,^! may be remov$ by heat+ ! tube & draw+ filt]$ air ?r\gh x1 b n by wa%+1 z x is difficult to obta9 wat] :i* leaves no residue on ! silica4 ,mak+ l>g] tubes & o!r app>atus ( ,silica4--,9 ord] to conv]t a small bulb ( silica into a l>g] "o or into a l>ge tube1 proce$ z foll[s3--,heat "o end ( a f9e rod ( silica & apply x to ! bulb s z to =m a r+ z %[n 9 ! figure4 ,!n heat ! r+ & ! end ( ! bulb till x s(t5s1 & exp& ! end by bl[+4 ,if ?is process is repeat$1 ! bulb fir/ becomes ovate & !n =ms a %ort tube :i* c be l5g!n$ at w1 b ! mo/ conv5i5t way to obta9 a v long tube is to make sev]al %ort] tubes ( ! requir$ diamet]1 & say #bjj to #bej mm4 9 l5g?1 & to jo9 ^! end to end4 ,x does n answ] to add lumps ( silica to ! end ( ! bulb1 = ! sides ( ! tube made 9 ?is way become too ?91 & bl[-holes are con/antly =m$ dur+ ! mak+ ( !m4 ,^! c be m5d$1 x is true1 b !y spoil ! appe>ance ( ! "w4 ,illu/ration ,tubes made 9 ! mann] describ$ above are ?ick5$ by add+ r+s ( silica & bl[+ !m :5 hot to spread ! silica4 ,if a comb9ation ( sev]al jets is employ$1 v l>ge tubes c be con/ruct$ 9 ?is way4 ,"o ( ,messrs4 ,baird & ,tatlock's workm5 lately blew a bulb ab\t #e cm4 9 diamet]1 & x 0 cle> t he c\ld h conv]t$ x into a long cyl9drical tube ( equal diamet] _h x be5 necess>y to d s4 ,v ?9 tubes ( #a4e cm4 diamet]1 & tubes ( consid]able ?ickness & ( equal size1 are easily made aft] "s practice1 & f9e capilli>ies & millimetre tube c be made ) ab\t equal read9ess4 ,if a v f9e tube ( ev5 bore is requir$1 x may be drawn f a small ?ick cyl9d] aft] a little practice4 ,:5 a tube becomes s l>ge t x _c be heat$ uni=mly on all sides by rotat+ x 9 ! flame1 x is conv5i5t to place a %eet ( silica 9 front ( ! flame a little beyond ! object to be heat$1 9 ord] t ! =m] may ?r[ back ! flame on ^? p>ts ( ! tube :i* are mo/ remote f ! jet4 ,a suitable plate may be made by /ick+ toge!r small lumps ( silica r5d]$ pla/ic by heat4 ,! silica tubes ?us made c be cut & brok5 l glass1 !y c be jo9$ toge!r be=e ! flame1 & !y c also be drawn into small] tubes :5 s(t5$ by heat4 ,9 ord] to make a side connection z 9 a ,t piece1 a r+ ( silica %\ld be appli$ to ! tube 9 ! position fix$ ^u = ! jo9t4 ,?is r+ mu/ !n be slightly exp&$1 a new r+ add$1 & s on1 till a %ort side tube is =m$4 ,to ?is x is easy to seal a long] tube ( ! requir$ dim5sions4 ,x is ?us possible to produce ,geissl] tubes1 small di/ill+ flasks1 etc4 ,solid rods ( silica are easily made by press+ toge!r ! s(t5$ ends ( ! f9e rods or ?reads previ\sly m5tion$4 ,su* rods & small masses c be gr\nd & poli%$ )\t anneal+ !m4 ,qu>tz ,fibres4--,^! 7 introduc$ into physical "w by ,mr4 ,boys 9 #ahhi4 ,!y may be made by atta*+ a f9e rod ( vitrifi$ qu>tz to ! tail ( a small /raw arr[ provid$ ) a ne$le-po9t2 plac+ ! arr[ 9 position on a cross-b[1 heat+ ! rod ( silica till x is ?or\ghly s(t5$ & !n lett+ ! arr[ fly f ! b[1 :5 x w c>ry ) x an extremely f9e ?read ( silica4 ,a little practice is necess>y to ensure success1 b a good op]ator c produce ?reads ( great t5acity & great uni=mity4 ,full] acc\nts ( ! process & ( ! v>i\s prop]ties & uses ( qu>tz fibres w be f\nd 9 ,mr4 ,boys' lectures 7,roy4 ,in/4 ,proc4 #ahhi1 & ,proc4 ,brit4 ,assn4 #ahij71 & 9 ,mr4 ,?relfall's ,laboratory ,arts4 ,,index4 ,air-traps1 #fi4 ,anneal+1 #bc4 ,app>atus ne$$ = ,glass-work+1 #aa4 ,app5dix1 #hb4 ,beg9n]s1 ,failures (1 #bb4 ,bell[s1 ,position (1 #c4 ---- ,v>i\s =ms (1 #g4 ,see also ,bl[]4 ,b5d+ ,glass ,tubes1 #bh4 ,bl[]1 ,automatic1 #h4 ,bl[-pipe1 ,*eap =m (1 #d4 ---- ,dim5sions (1 #d-e4 ---- ,flet*]'s ,automaton1 #f4 ---- ,flet*]'s ,comp\nd1 #f4 ---- ,gimm+ham's1 #f4 ---- ,h]apa?'s1 #f4 ---- ,jets = !1 #g4 ---- ,use ( !1 #h4 ,see also ,flames4 ,bl[-pipes1 ,use ( sev]al 9 comb9ation1 #ba4 ,bru% ,flame1 #i4 ---- ,oxidis+1 #bj4 ,bulbs1 ,me?ods ( bl[+1 #dg4 ,calibrat+ ,app>atus1 #gf-ha4 ,camphorat$ ,turp5t9e1 #aa4 ,cetti's ,vacuum ,tap1 #ff4 ,*>coal ,pa/ils1 #aa4 ,*ok+ or ,contract+ ! ,bores ( ,tubes1 #ce4 ,comb9+ ! ,p>ts ( ,complicat$ ,app>atus1 #fa4 ,combu/ion ,tube1 h[ to "w x1 #be4 ,contract+ ! ,bore ( a ,tube1 #ce4 ,cotton ,wool = ,anneal+1 #bd4 ,cutt+ ,glass ,tubes1 #bf1 #bg1 #bh4 ,divid+ a ,l9e into ,equal ,p>ts1 #ge4 ,electrodes1 #ch1 #ee4 ,electrolysis1 ,mak+ ,app>atus =1 #ei4 ,files = ,cutt+ ,glass1 #bg4 ,flame1 ! ,po9t$1 #h4 ---- ! ,bru%1 #i4 ---- ! ,oxidis+ ,bru%1 #bj4 ---- ! ,smoky1 #aj4 ,flet*]'s ,automaton ,bl[-pipe1 #f4 ,flet*]'s ,comp\nd ,bl[-pipe1 #f4 ,funnels1 ,?i/le-head$1 #eg4 ,gimm+ham's ,bl[-pipe1 #f4 ,gimm+ham's ,vacuum ,tap1 #fh4 ,glass1 ,anneal+1 #bc4 ---- ,devitrification (1 #ae4 ---- ,me?od ( ,work+ ) ,lead1 #ag4 ---- ,me?od ( ,work+ ) ,soda1 #bb4 ---- ,nature (1 #ab4 ---- ,pres5t+ to ! ,flame1 #af4 ,glass ,tubes1 ,b5d+1 #bh4 ---- ,bord]+1 #ca4 ---- ,*>act]s ( good1 #ad4 ---- ,*ok+1 #ce4 ---- ,clean+1 #ae4 ,glass ,tubes1 ,cutt+1 #bf1 #bg1 #bh4 ---- ,pi]c+1 #cg4 ---- ,pur*ase (1 #ab4 ---- ,seal+1 #cb4 ---- ,seal+ ,h]metically1 #eh4 ---- ,sizes (1 #hb4 ---- ,weld+ or ,sold]+1 #ci1 #fb4 ---- ,wid5+ ! ,ends (1 #cf4 ,graduat+ ,app>atus1 #gj4 ,gr9d+ ,/opp]s1 #ea4 ,h]apa?'s ,bl[-pipe1 #f4 ,h(man's ,app>atus = ,electrolysis1 #ei4 ,inside ,jo9ts1 #dc4 ,jets = ,bl[-pipes1 #g4 ,jo9ts1 ,air-tight1 #fd4 ,lead ,glass1 ,me?od ( ,work+ )1 #ag4 ,lead ,glass1 ,black5+ (1 #ag4 ,light1 ,effect (1 9 ,work+1 #c4 ,l9e1 to ,divide into ,equal ,p>ts1 #ge4 ,m]cury ,jo9ts1 ,v>i\s1 #fd4 ,non-spl9t]+ ,silica1 ,prep>ation (1 f ,qu>tz1 #hh4 ,ozone ,g5]ator1 ,to ,make an1 #dd4 ,pa/ils ( ,*>coal1 #aa4 ,pi]c+ ,tubes1 etc41 #cg4 ,plat9um ,electrodes1 ,seal+ 91 #ch1 #ee4 ,po9t$ ,flame1 !1 #i4 ,qu>tz ,fibres1 #id4 ,r\nd+ ,ends ( ,tubes1 #ca4 ,seal+ or ,clos+ ,op5+s 9 ,tubes1 #cb4 ,side-tubes1 ,fix+1 #da4 ,smoky ,flame1 #aj4 ,soda ,glass1 ,me?od ( ,work+1 #bb4 ,sold]+ or ,weld+1 #ci1 #fb4 ,spiral ,tubes1 #ef4 ,/opp]s1 ,mak+ & ,gr9d+1 #ea4 ,table = ,glass-bl[]1 #c4 ,taps1 ,vacuum1 #fe4 ,?i/le-head$ ,funnels1 #eg4 ,traps1 ,air1 #fi4 ,tube1 ,combu/ion1 h[ to "w x1 #be4 ,tubes4 ,see ,glass ,tubes4 ---- ,t-1 #da4 ---- ,u-1 #ef4 ,turp5t9e1 ,camphorat$1 = ,gr9d+1 #aa4 ,u-,tubes1 #ef4 ,vacuum ,taps1 #fe-fh4 ---- ,tube1 ,to ,make a1 #fj4 ,vitre\s ,silica1 ,app>atus requir$ = ,mak+1 #hi4 ---- ,behavi\r "u sudd5 *anges ( ,temp]ature1 #hg4 ---- ,bulbs1 etc41 ,mak+ ,jo9ts on1 #ic4 ---- ,expansion (1 #hf4 ---- ,h>dness (1 #he4 ---- ,insulat+ ,p[] (1 #he4 ---- ,melt+ ,po9t (1 #he4 ---- ,p]meability to ,gases1 #hg4 ---- ,prop]ties (1 #hd4 ---- ,rods1 ,mak+ ,jo9ts on1 #id4 ---- ,tubes1 ,me?od ( ,mak+1 #ij4 ---- ,tubes1 ,mak+ ,jo9ts on1 #id4 ,weld+ or ,sold]+ ,tubes toge!r1 #ci1 #fb4 ,:ite ,enamel1 ,uses (1 #ci1 #ef4 ,wid5+ ! ,ends ( ,tubes1 #cf4 ,work+-place1 #b4 ,pr9t$ by ,t4 & ,a4 ,,con/able1 ,pr9t]s to ,8 ,maje/y at ! ,ed9burgh ,univ]sity ,press1 ,scotl&