,,laboratory ,,manual ,,( ,,glass-,,bl[+ ,mc,graw-,hill ,book ,company ,publi%]s ( ,books = ,electrical ,_w ,eng9e]+ ,record ,railway ,age ,gazette ,signal ,eng9e] ,electric ,railway ,j\rnal ,metallurgical & ,*emical ,eng9e]+ ,! ,eng9e]+ & ,m9+ ,j\rnal ,eng9e]+ ,news ,am]ican ,ma*9i/ ,am]ican ,eng9e] ,coal ,age ,p[] ,,laboratory ,,manual ,,( ,,glass-,,bl[+ ,,by ,,francis ,c4 ,,fr>y1 ,,ph4 ,d4 ,,assi/ant ,,pr(essor ,,( ,,*emi/ry ,,univ]sity ,,( ,,m9nesota ,mc,g,r,a,w-,,hill ,,book ,,company1 ,,inc4 #bci ,,we/ #ci,,? ,,/reet1 ,,new ,,york #f ,,b\v]ie ,,/reet1 ,,london1 ,e4 ,c4 #aiad ,,copyright1 #aiad1 ,,by ,,! ,mc,g,r,a,w-,,hill ,,book ,,company1 ,,inc4 ,,preface ,! purpose ( ?is little book is to provide a cle> & detail$ discussion ( ! elem5ts ( glass-bl[+4 ,_m laboratories 9 ?is c\ntry1 especially 9 ! we/1 are locat$ a long way f any pr(essional glass-bl[]1 & ! "t & money sp5t 9 %ipp+ brok5 app>atus sev]al hundr$ miles to be m5d$ c\ld (t5 be sav$ if "s ( ! laboratory =ce c\ld seal on a new /opcock1 replace a brok5 tube1 or make "s tempor>y repairs4 ,_m m5 9 physical or *emical laboratories h occasion to modify "s piece ( app>atus design$ p]haps = o!r uses1 or to design new app>atus4 ,to su* also1 ! ability to p]=m "s ( ! op]ations h]e9 describ$ may be v valuable4 ,no orig9ality is claim$ = ! me?ods "h describ$4 ,!y are ^? :i* ! au?or has f\nd mo/ suitable & conv5i5t 9 8 own "w1 & mo/ easily le>n$ by /ud5ts4 ,! aim has be5 to describe ea* op]ation 9 su* detail t a beg9n] c foll[ ! process )\t help &1 ) practice1 atta9 satisfactory results4 ,x is1 h[ev]1 mu* easi] to p]=m any ( ! op]ations describ$1 aft] see+ "s "o else p]=m x correctly2 s9ce ! temp]ature1 ! exact "t to beg9 bl[+ ! glass1 & _m o!r little details are v difficult to obta9 f a description4 ,x has n be5 ?\ght wor? :ile to describe ! process ( mak+ /opcocks1 !rmomet]s1 vacuum tubes1 etc41 z su* ?+s c be pur*as$ m *eaply & ( mu* bett] quality ?an any amateur c make unless he is will+ to sp5d a v l>ge am\nt ( "t 9 practice4 ,= simil> reasons ! manipulation ( qu>tz glass has be5 omitt$4 ,! au?or w be grateful = all sugge/ions & criticisms t5d+ to improve ! me?ods pres5t$4 ,if "s ( !m appe> to be giv5 9 excessive detail1 ! read] w rememb] t _m ?+s :i* are obvi\s to ! exp]i5c$ work] are n s to ! beg9n]1 & t x is ! little details 9 ! manipulation :i* (t5 spell success or failure 9 glass-bl[+4 ,f4 ,c4 ,f4 ,,m9neapolis1 ,,m9n41 ,janu>y1 #aiad4 ,,cont5ts ,,page ,preface v ,,*apt] ,i ,,mat]ials ,,& ,,app>atus #a ,v>ieties & defects ( glass--,devitrification--,anneal+ glass--,bl[pipe & bell[s--,light--,arrangem5t ( ex]cises4 ,,*apt] ,,ii ,,g5]al ,,op]ations #g ,cutt+1 b5d+1 con/rict+ & flang+ ! tub+--,me?ods ( rotation & bl[+4 ,,*apt] ,,iii ,,elem5t>y ,,ex]cises #af ,jo9+ two pieces ( tub+ ( ! same diamet]--,! tee tube--,jo9+ two tubes ( diff]5t diamet]s--,bl[+ bulbs4 ,,*apt] ,,iv ,,advanc$ ,,ex]cises #ce ,seal+ a tube ?r\gh ano!r tube3 ,! gas-wa%+ tube1 suction pump1 & ,kjeldahl trap4 ,,*apt] ,v ,,modifi$ ,,me?ods ,,& ,,special ,,op]ations #dc ,capill>y tub+--,glass rod--,m5d+ /opcocks--,clos$ circuits ( tub+--,spirals--,gr\nd jo9ts--,seal+ 9 plat9um wire--,seal+ vacuum tubes--,clos$ tubes = heat+ "u pressure4 ,,index #ei ,,laboratory ,,manual ,,( ,,glass-,,bl[+ ,,*apt] ,i ,,mat]ials ,,& ,,app>atus ,"o ( ! mo/ important factors 9 ! success ( any piece ( glass-bl[+ is ! glass employ$4 ,z is well kn[n1 !re are two g5]al v>ieties ( glass3 ,lead glass & soda glass4 ,=m]ly mu* app>atus 0 made ( lead glass1 b at pres5t x is v seldom met )1 except 9 ! little drops ( special glass us$ to seal plat9um wires into ! l>g] sizes ( tubes4 ,lead glass is s(t] & m readily fusible ?an soda glass1 b has ! disagreeable prop]ty ( gr[+ black 9 a few seconds unless work$ 9 a /rong oxidiz+ flame4 ,?is may be prev5t$ by us+ a hiss+ flame1 ) a l>ge excess ( air1 & work+ 9 ! extreme end ( ! flame2 or ! black lead =m$ may ?us be reoxidiz$1 & ! glass re/or$ to its orig9al cle>ness4 ,almo/ all ! s(t glass on ! m>ket is a soda glass1 al?\gh sometimes "p ( ! soda is replac$ by pota%4 ,mo/ ( ! h>d glass appe>s to be a pota% glass4 ,! foll[+ qualities are desirable 9 a glass = ord9>y work+3 7#a7 mod]ately l[ work+ temp]ature1 7#b7 fre$om f air bubbles1 /riations & irregul>ities1 7#c7 prop] composition1 s t ! glass w n devitrify or cry/allize :ile be+ h&l$ at its work+ temp]ature1 7#d7 ability to )/& rapid heat+ )\t crack+4 ,! work+ temp]ature ( diff]5t samples ( s-call$ s(t glass v>ies a good deal1 & is be/ det]m9$ by trial4 ,! glass %\ld become almo/ s(t en\gh = bl[+ 9 a flame t /ill %[s a little yell[ ne> ! tip1 s t at ! highe/ temp]ature ( ! flame x may fl[ fairly freely & ?us easily elim9ate irregul>ities 9 ?ickness4 ,if ! glass is too h>d1 ! %r9k+ ( ! glass1 collection ( mat]ial = a bulb1 & 9 fact mo/ ( ! work+ processes w be sl[]1 & ! glass w n /ay at its work+ temp]ature long en\gh aft] its removal f ! flame to p]mit x to be prop]ly bl[n4 ,air bubbles 9 ! orig9al bat* ( glass are drawn out into long hair-l tubes dur+ ! process ( manufacture4 ,:5 su* tub+ is work$1 ! walls ( ^! microscopic tubes collapse 9 spots1 & ! air ?us enclos$ w (t5 collect z a small bubble 9 ! wall1 ?us weak5+ x4 ,irregul>ities are ( v>i\s k9ds4 ,"s ( ! l>g] sizes ( ?9-wall$ tub+ (t5 h "o half ( _! walls mu* ?ick] ?an ! o!r1 & su* tub+ %\ld only be us$ = ! simple/ "w4 ,"s tub+ has occasional knots or lumps ( unfus$ mat]ial4 ,! re/ ( ! tube is usually all "r1 b (t5 ! defective "p mu/ be cut out4 ,! pres5ce ( /riations runn+ along ! tube is g5]ally an indication ( h>d1 inf]ior glass4 ,crook$ness & non-uni=mity ( diamet] are tr\blesome only :5 long pieces mu/ be us$4 ,devitrification is "o ( ! wor/ faults glass c possibly h4 ,x is especially common 9 old glass1 & 9 glass :i* has conta9$ acids4 ,x seems to be ( two sorts4 ,"o v>iety manife/s itself on ! surface ( ! glass be=e x rea*es its work+ temp]ature1 b if ! glass be heat$ to ! highe/ temp]ature ( ! flame x w disappe> except 9 ! portion at ! edge ( ! heat$ "p4 ,! glass seems to "w all "r1 b an ugly cry/alliz$ r+ is left at ! edge ( ! portion heat$4 ,?is k9d appe>s mo/ frequ5tly 9 old glass :i* 0 orig9ally ( good quality1 b has 9 "t be5 sup]ficially alt]$1 probably by ! loss ( alkalies4 ,! o!r v>iety ( devitrification does n appe> :5 ! glass is fir/ heat$2 b aft] x has be5 ma9ta9$ at or above its work+ temp]ature = a long] or %ort] "t1 x w be notic$ t ! out] surface has lo/ its smoo?ness1 & appe>s to be cov]$ ) m9ute wr9kles4 ,x w also be f\nd t ! glass has become h>d]1 s t x becomes impossible to "w x easily4 ,fur!r heat+ only makes ! matt] worse1 z does ! use ( a high] temp]ature f ! />t4 ,9 fact x w (t5 be f\nd t a piece ( comp>atively s(t glass :i* devitrifies almo/ at once 9 a hiss+ flame c be work$ )\t s]i\s difficulty if c>e be tak5 to use a flame /ill decid$ly t+$ ) yell[4 ,ev5 good glass w beg9 to devitrify 9 ?is way if heat$ too long at ! highe/ temp]ature ( ! flame1 s c>e %\ld always be tak5 7#a7 to r$uce ! "t ( heat+ ( any spot ( glass to a m9imum2 i4e41 get ! desir$ result at ! fir/ attempt1 if possible1 or at lea/ ) ! m9imum ( reheat+ & doctor+1 & 7#b7 avoid keep+ ! glass at ! highe/ temp]ature ( ! flame any long] ?an necess>y4 ,?is may be accompli%$ by do+ all heat+1 %r9k+1 etc41 ( ! glass 9 a flame m or less t+$ ) yell[1 & only rais+ ! temp]ature to ! highe/ po9t :5 ready to bl[ ! glass4 ,?is k9d ( devitrification is app>5tly due to volatilization ( ! alkalies f ! glass 9 ! flame1 & x is said t x c be p>tly rem$i$ or prev5t$ by hold+ a swab ( cotton saturat$ ) a /rong solution ( common salt 9 ! flame f "t to "t z ! glass is heat$4 ,! t\ghness ( glass1 i4e41 its ability to )/& v>iations ( temp]ature1 dep5ds on its composition & ! c>e tak5 9 its anneal+4 ,9 g5]al1 l>ge pieces ( glass %\ld be heat$ v sl[ly 9 ! smoky flame1 & ! l>g] ! diamet] ( ! tube ! great] ! l5g? :i* mu/ be kept w>m to prev5t crack+4 ,all l>ge pieces %\ld be c>efully heat$ ov] _! :ole circumf]5ce to ! po9t :]e ! soot deposit burns (f1 be=e be+ f9ally cool$4 ,aft] be+ ?us heat$ !y are cool$ 9 a l>ge smoky flame until well coat$ ) soot1 !n ! flame is gradually r$uc$ 9 size & ! object f9ally cool$ 9 ! hot air above x until x w n set fire to cotton4 ,if ?\ght necess>y1 x may !n be well wrapp$ 9 cotton & all[$ to cool 9 ! air4 ,if n prop]ly anneal$ ! place heat$ may crack spontane\sly :5 cold1 & x is q c]ta9 to crack if x is reheat$ lat]4 ,next 9 importance to ! glass are ! bl[-pipe & ! bell[s4 ,any good bla/ lamp1 su* z is ord9>ily us$ 9 a *emical laboratory = ! ignition ( precipitates1 w be satisfactory2 provid$ x gives a smoo? regul> flame ( suffici5t size = ! "w 9 h&1 & :5 turn$ d[n w give a %>p-po9t$ flame ) well-def9$ p>ts4 ,:]e gas is n available1 an ord9>y gasol9e bl[-tor* does v well = all op]ations requir+ a l>ge flame1 & a m\? bl[-pipe arrang$ to bl[ ?r\gh a k]os5e flame does well = a small flame4 ,sev]al deal]s make bl[-tor*es = oil or alcohol :i* are arrang$ to give a small well-def9$ flame1 & !y w\ld d\btless be v satisfactory = glass-"w4 ,any good bell[s w be satisfactory if x does n leak & w give a /eady supply ( air "u suffici5t pressure = ! maximum size ( flame giv5 by ! lamp us$4 ,a bell[s ) a leaky valve w give a pulsat+ flame :i* is v annoy+ & makes good "w v difficult4 ,:5 compress$ air is available x c be us$1 b if possible x %\ld be arrang$ s t ! supply c be controll$ by ! foot1 z bo? h&s are usually ne$$ to hold ! "w4 ,= ! same reason ! supply ( air is usually regulat$ by v>y+ ! rate ( op]ation ( ! bell[s1 r ?an by adju/+ ! valve ( ! bla/-lamp4 ,on ! o!r h&1 x w be f\nd be/ to always adju/ ! fl[ ( ! gas by means ( ! cock on ! lamp1 r ?an t at ! supply pipe4 ,! op]ator mu/ h complete control ov] ! flame1 & be able to *ange its size & "* at %ort notice )\t giv+ ! "w a *ance to cool1 & (t5 )\t ceas+ to support x ) bo? h&s4 ,glass-bl[+ %\ld be done 9 a good light1 b pref]ably n 9 direct sunlight4 ,! op]ator %\ld be seat$ 9 a *air or on a /ool ( su* a height t :5 work+ he may com=tably re/ "o or bo? elb[s on ! table4 ,! com=t ( ! op]ator has a decid$ influ5ce on ! "* ( 8 "w2 especially 9 ! case ( a beg9n]1 :o (t5 defeats 8 purpose by assum+ uncom=table & /ra9$ positions4 ,/ead9ess & exact control ( bo? h&s are ess5tial 9 mo/ op]ations2 any uncom=table or /ra9$ position tires ! muscles & weak5s ! control ( ! op]ator ov] !m4 ,9 ! arrangem5t ( ! ex]cises "h pres5t$1 sev]al factors h be5 consid]$4 ,x is important t ! fir/ ex]cises be simple1 al?\gh n necess>ily ! simple/1 & !y %\ld tea* ! fundam5tal op]ations :i* w be us$ & amplifi$ lat]4 ,!y %\ld 9 !mselves be ?+s :i* are ( importance & commonly us$ 9 glass-"w1 & !y %\ld be s arrang$ t ! fundam5tal po9ts1 su* z ! rotation ( glass1 ! prop] temp]ature1 bl[+ & %r9k+ ! glass may be le>n$ ) a m9imum exp5diture ( "t1 glass & gas4 ,x is !re=e recomm5d$ t ! beg9n] take !m up 9 ! ord] giv51 at lea/ z f> z ,no4 #g1 & t ea* be ma/]$ be=e attempt+ ! next4 ,! beg9n] %\ld n leave ! fir/ ex]cise1 = example1 until he c jo9 toge!r two pieces ( tub+ s t !y =m "o piece ( sub/antially uni=m inn] & out] diamet]1 & )\t ?ick or ?9 spots4 ,f two to f\r practice p]iods ( two h\rs ea* %\ld suffice = ?is4 ,?is *apt] & ! foll[+ "o %\ld also be frequ5tly read ov]1 z _m ( ! po9ts discuss$ w n be und]/ood at fir/ & _m ( ! manipulations describ$ w n be necess>y 9 ! simpl] ex]cises4 ,,*apt] ,,ii ,,g5]al ,,op]ations ,cutt+ ! ,glass4--,= ?is purpose a glass-knife is pref]r$ to a file1 if ! glass is cold3 if x is hot a file mu/ always be us$1 & its edge slightly moi/5$ to prev5t draw+ ! temp]4 ,! glass-knife is simply a flat piece ( h>d /eel1 ) ! edges gr\nd %>p on an em]y :eel4 ,! bevel ( ! edge %\ld be f #cj to #fj degrees4 ,an old flat file c easily be gr\nd into a suitable knife4 ,! glass-knife makes a n>r[] scrat* ?an ! file b appe>s m likely to />t ! m9ute crack :i* is to cause ! tube to break at t po9t1 & ! break is m likely to give a good squ>e end4 ,! scrat* %\ld be made by pass+ "p ( ! knife or file once across ! glass1 nev] by saw+ ! tool back & =?4 ,?is latt] proc$ure dulls ! tool v quickly4 ,9 break+ a piece ( glass tub+1 _m p]sons =get t x is necess>y to pull ! ends ap>t1 z well z to b5d ! tube v slightly 9 su* a direction z to op5 up ! m9ute crack />t$ 9 ! scrat*4 ,c>e 9 break+ ! tube is ess5tial1 z x is impossible to d z good "w ) unev5 ends z ) squ>e ones4 ,:5 tub+ ( l>ge diamet] or ?9 wall is to be cut1 x is (t5 bett] n to attempt to break x 9 ! usual way1 b to heat a v small globule ( glass 7#a_/af to #a_/h in* diamet]7 to r$ heat1 & t\* x to ! scrat*4 ,?is w usually />t ! crack ar\nd ! tube2 if x has n proce$$ f> en\gh1 or has n gone 9 ! desir$ direction1 x may be l$ along ) a hot po9t ( glass4 ,?is is put a little beyond ! end ( ! crack1 & z ! latt] gr[s out t[>d x1 mov$ along ! pa? :]e ! crack is desir$4 ,?is po9t ( glass is also v useful 9 break+ (f v %ort ends ( tubes1 :]e !re is n room to get a firm en\gh hold & suffici5t lev]age to break ! tube 9 ! ord9>y way1 & = break+ tubes atta*$ to l>ge or heavy objects1 :i* w\ld be likely to make tr\ble if treat$ 9 ! ord9>y way4 ,ano!r way ( cutt+ l>ge tub+1 especially if x has r ?ick walls1 is to make a scrat* 9 ! usual way1 & !n turn on ! smalle/ & %>pe/ possible flame ( ! bla/ lamp4 ,! tube is next tak5 9 bo? h&s & held horizontally above ! flame s t ! scrat* is exactly ov] x4 ,! tub+ is n[ rotat$ rapidly ab\t its axis1 & l[]$ s t ! flame is j tang5t to its l[] side4 ,aft] ab\t t5 seconds ( heat+1 x is remov$ f ! flame & ! hot portion quickly brea!d ^u1 :5 x w g5]ally crack ap>t v nicely4 ,c>e mu/ be tak5 to hold ! tube at "r angles to ! flame dur+ ! heat+1 & to rotate x s t only a n>r[ /rip ( ! circumf]5ce is heat$1 & ! scrat* %\ld be 9 ! c5t] ( ?is heat$ /rip4 ,by ?is means tub+ z l>ge z two in*es 9 diamet] is readily brok54 ,griff9's glass cutt]1 :i* conta9s a h>d5$ /eel :eel1 l t on any ord9>y w9d[-glass cutt]1 & a device by :i* ?is c be made to make a true cut cle> ar\nd ! tube1 is a v h&y article1 especially = l>ge tub+1 & may be obta9$ f any deal]s 9 *emical app>atus4 ,b5d+ ,glass4--,inasmu* z ?is is "o ( ! commone/ op]ations 9 ! laboratory1 x is assum$ t ! read] kn[s h[ to p]=m x4 ,h[ev]1 x %\ld be not$ t 9 ord] to obta9 ! be/ results a broad 7fi%-tail burn]7 flame %\ld g5]ally be us$1 & ! tube rotat$ on its axis dur+ ! heat+1 & all[$ to b5d mo/ly by its own weight4 ,if l>ge tub+ is to be b5t1 "o end mu/ be /opp]$ & great c>e us$4 ,:5ev] ! tube %[s signs ( collaps+ or becom+ de=m$1 x mu/ be g5tly bl[n out into %ape1 heat+ ! desir$ spot locally if necess>y4 ,a bla/-lamp is likely to be m useful "h ?an ! fi%-tail burn]4 ,draw+ ,out a ,tube4--,mo/ /ud5ts le>n ?is ! fir/ day ( _! laboratory "w 9 *emi/ry1 b few take pa9s to d x well4 ,! tube %\ld be heat$ 9 ! flame ( a ,buns5 burn]1 or bla/ lamp 7pref]ably ! latt]7 until x is v s(t4 ,dur+ ?is "t x mu/ be cont9u\sly rotat$ ab\t its axis1 & s held t ! edges ( ! heat$ zone are %>ply def9$2 i4e41 x %\ld n be all[$ to move back & =? along its own axis4 ,:5 s hot t x _c long] be held 9 %ape1 ! tube is remov$ f ! flame1 & ! ends sl[ly & regul>ly drawn ap>t1 cont9u+ ! rotation ( ! tube ab\t its axis4 ,by regulat+ ! rate ( draw+ & ! l5g? ( tube heat$1 ! desir$ l5g? & diamet] ( capill>y may be obta9$4 ,! tube %\ld always be rotat$ & kept 9 a /raight l9e until ! glass has set1 s t ! capill>y may h ! same axis z ! ma9 tube4 ,?is capill>y or tail is (t5 a v necess>y h&le 9 glass-bl[+1 & if x is n /raight & true1 w cont9ually make tr\ble4 ,9 draw+ out v l>ge tub+1 say f "o to two in*es 9 diamet]1 x is (t5 necess>y to draw ! tube 9 ! flame1 proce$+ v sl[ly & at a l[] temp]ature ?an w\ld be us$ ) small tub+4 ,?is is p>tly on acc\nt ( ! difficulty ( heat+ l>ge tub+ uni=mly to a high temp]ature1 & p>tly 9 ord] to prev5t mak+ ! conical "p ( ! tube too ?9 = subsequ5t op]ations4 ,con/rict+ a ,tube4--,:]e a con/riction is to be made 9 a tube1 ! above me?od mu/ be modifi$1 z ! /r5g? ( ! tube mu/ be ma9ta9$1 & ! con/rict$ portion is usually %ort4 ,small tubes are (t5 con/rict$ )\t mat]ially *ang+ _! outside diamet]1 by a process ( ?ick5+ ! walls4 ,! tube is heat$ be=e ! bla/ lamp1 rotat+ x ab\t its axis z lat] describ$1 & z x s(t5s is gradually pu%$ toge!r s z to ?ick5 ! walls at ! heat$ po9t1 z 9 a1 ,fig4 #a4 ,:5 ?is op]ation has proce$$ f> en\gh1 ! tube is remov$ f ! flame1 & ! ends cauti\sly & g5tly drawn ap>t1 cont9u+ ! rotation ( ! tube ab\t its axis & tak+ c>e n to draw too rapidly at fir/4 ,! result+ tube %\ld h a uni=m ext]ior diamet]1 z %[n 9 b1 ,fig4 #a4 ,illu/ration3 ,,fig4 #a4--;,con/rict+ a tube4 ,?is me?od ( con/riction is n suit$ to tubes mu* ov] #a_/d in* 9 diamet]1 s9ce ! mass ( glass 9 ! con/rict$ "p becomes s ?ick z to be difficult to h&le :5 hot1 & likely to crack on cool+4 ,l>g] tubes are !re=e con/rict$ by heat+ 9 a n>r[ flame1 ) con/ant rotation1 & :5 s(t1 alt]nately g5tly pull+ ! ends ap>t & pu%+ !m toge!r1 ea* motion be+ s regulat$ t ! diamet] ( a %ort section ( ! tube is gradually r$uc$1 :ile ! ?ickness ( ! wall ( ! r$uc$ portion rema9s ! same z t ( ! re/ ( ! tube1 or increases only slightly4 ,?is pull+ & pu%+ ( ! glass takes place 9 ! flame1 :ile ! rotation is be+ cont9u$ regul>ly4 ,! result may appe> z indicat$ 9 c1 ,fig4 #a4 ,! /r5g? ( ! "w dep5ds ^u ! ?ickness ( ! walls ( ! con/rict$ portion1 :i* %\ld nev] be less ?an t 9 ! ma9 tube1 & usually a little great]4 ,?is op]ation is mo/ successful ) tub+ hav+ a relatively ?9 wall4 ,flang+ a ,tube4--,?is op]ation produces ! *>act]i/ic flange se5 on te/-tubes1 necks ( flasks1 etc41 ! object be+ tw(old3 to f9i% ! end neatly & to /r5g!n x s t a cork may be ins]t$ )\t break+ x4 ,?is flang+ may be done 9 sev]al ways4 ,9 any case ! fir/ op]ation is to cut ! tube to a squ>e end1 & !n heat ?is end s t ! extreme sixte5? or eigh? ( an in* ( x is s(t & beg9s to %r9k4 ,! tube is ( c\rse rotat$ dur+ ?is heat+1 :i* %\ld take place 9 a flame ( slightly great] diamet] ?an ! tube1 if possible4 ,! flange is n[ produc$ by exp&+ ?is s(t5$ "p ) "s suitable tool4 ,a cone ( *>coal has be5 recomm5d$ = ?is purpose1 & works fairly well1 if made s its height is ab\t equal to ! diamet] ( its base4 ,! tube is rotat$ & ! cone1 held 9 ! o!r h&1 is press$ into ! op5 end until ! flange is =m$4 ,a pyramid ) eight or t5 sides w\ld probably be bett] ?an ! cone4 ,illu/ration3 ,,fig4 #b4--;,flang+ tool4 ,a bett] flang+ tool is made f a triangul> piece ( copp] or brass1 ab\t #a_/af in* ?ick1 & m\nt$ 9 a suitable h&le4 ,su* a tool is %[n 9 ,fig4 #b1 be+ cut f a %eet ( copp] & provid$ ) a h&le made by wrapp+ asbe/os pap] moi/5$ ) sodium silicate solution ab\t ! %ank ( ! tool4 ,x is well to h sev]al sizes & %apes ( ^! tools1 = diff]5t sizes ( tub+4 ,! two sizes mo/ us$ w be ^? hav+ ab\t ! foll[+ dim5sions3 7#a7 a #b in*es1 b #a in*2 7#b7 a #a in*1 b #a in*4 ,:5 ! end ( ! tube is s(t5$1 ! tool is ins]t$ at an angle1 z indicat$ 9 ,fig4 #c1 & press$ aga9/ ! s(t "p1 :ile ! tube is quickly rotat$ ab\t its axis4 ,if ! flange is insuffici5t ! op]ation may be repeat$4 ,! tool %\ld always be w>m$ 9 ! flame be=e use1 & occasionally greas$ by t\*+ x to a piece ( wax or p>aff94 ,aft] ! flange is complete1 ! end mu/ be heat$ aga9 to ! s(t5+ temp]ature & cool$ sl[ly1 to prev5t x f crack+4 ,illu/ration3 ,,fig4 #c4--;,flang+ a tube ) flang+ tool4 ,illu/ration3 ,,fig4 #d4--;,flang+ a tube ) c>bon rod or wire4 ,"s glass-bl[]s use a small c>bon rod1 ab\t #c_/af in* 9 diamet]1 z a flang+ tool = tubes l>g] ?an ab\t #c_/h in* diamet]1 & a small iron wire or simil> piece ( metal = small] tubes4 ,9 ?is case ! tube is heat$ z above describ$1 & ! rod or wire ins]t$ 9 ! end at an angle & press$ aga9/ ! s(t5$ "p1 z indicat$ 9 ,fig4 #d1 :ile ! tube is rotat$ ab\t its axis4 ,= l>ge heavy tubes a l>g] c>bon w\ld be us$4 ,rotation ( ! ,tube4--,?is is ! fundam5tal manipulation 9 glass-bl[+1 & ^u x m ?an all else dep5ds ! uni=mity & f9i% ( ! "w1 & (t5 ! possibility ( accompli%+ ! "w at all4 ,directions = x w be giv5 on ! assumption t ! read] is "r-h&$2 if o!rwise1 ! position ( ! h&s is ( c\rse rev]s$4 ,! object ( rotation is to insure ev5 heat+ ( ! :ole circumf]5ce ( ! tube at ! po9t ( attack1 to equalize ! effect ( gravity on ! hot glass & prev5t x f fall+ out ( %ape :5 s(t1 & to keep ! p>ts ( ! tube on ea* side ( ! heat$ portion 9 ! same /raight l9e4 ,9 rotat+ ! tube1 bo? h&s mu/ be us$1 s t ! two ends may revolve at ! same rate & ! glass 9 ! hot "p n be twi/$4 ,! rotation is p]=m$ by ! ?umb & fir/ f+] ( ea* h&1 ! o!r f+]s s]v+ to support ! tube4 ,z x is almo/ always necess>y to foll[ rotat+ & heat+ a tube by bl[+ x1 ! h&s %\ld be s plac$ t x w be easy to br+ ! "r-h& end up to ! m\? )\t %ift+ ! hold on ! glass4 ,= ?is reason ! left h& grasps ! glass ) ! palm d[n1 & ! "r h& ) ! palm turn$ t[>d ! left4 ,if !re is any *oice1 ! long] & heavi] "p ( ! tube is usually giv5 to ! left h&1 & x is plann$ to bl[ into ! %ort] end4 ,?is is because x is easi] to support ! tube ) ! h& :i* has ! palm d[n4 ,?is support is accompli%$ by b5d+ ! h& at ! wri/ s t x po9ts slightly d[nw>d1 & !n curl+ ! second1 ?ird & little f+]s 9 "u ! tube1 :i* is held betwe5 !m & ! palm4 ,?is support %\ld be loose en\gh s t ! ?umb & fir/ f+] c easily cause ! tube to rotate regul>ly on its axis1 b firm en\gh to c>ry all ! weight ( ! tube1 leav+ ! ?umb & fir/ f+] no?+ to d b rotate x4 ,! h& mu/ be s turn$1 & ! o!r f+]s s b5t1 t ! ?umb & fir/ f+] /ret* out ne>ly to _! full l5g? to grasp ! tube com=tably4 ,! "r h& is held ) ! palm t[>d ! left1 ! f+]s except ! fir/ slightly b5t1 & ! tube held betwe5 ! fir/ f+] & ! ?umb :ile x re/s on ! second f+] & t portion ( ! h& betwe5 ! base ( ! fir/ f+] & ! ?umb4 ,rotation ( ! tube is accompli%$ by roll+ x betwe5 ! ?umbs & fir/ f+]s3 ! rotation be+ cont9u$ 9 ! same direction regul>ly1 & n rev]s$4 ,x is bett] to roll sl[ly & ev5ly1 ) a s]ies ( light t\*es1 ea* ( :i* moves ! tube a little1 ?an to attempt to turn ! tube a half a revolution or s ) ea* motion ( ! h&s4 ,! h&s mu/ be held /eady1 & ! tube mu/ be "u good control at all times1 s t bo? ends may be rotat$ at ! same angul> velocity1 ev5 ?\gh !y may be ( diff]5t diamet]s1 & ! tube be nei!r drawn ap>t nor pu%$ toge!r unless su* a motion is expressly desir$1 z x sometimes is4 ,! hot "p ( ! glass mu/ be con/antly wat*$ to see t x is uni=mly rotat$ & n twi/$1 nor pull$ out or pu%$ toge!r m ?an is desir$4 ,c>e mu/ also be tak5 to keep ! p>ts ( ! tube 9 ! same /raight l9e1 or z ne> x z possible1 dur+ ! heat+ & all o!r manipulations4 ,:5 flang+ a tube1 x is held & rotat$ ) ! left h& z above describ$1 :ile ! "r h& holds ! flang+ tool4 ,:5 "p ( ! end ( a tube mu/ be heat$1 z 9 ,ex]cise #f1 & rotation mu/ be v c>efully p]=m$ & cont9u$ dur+ ! bl[+1 bo? h&s are us$4 ,! "r h& is held z above describ$1 & ! left h& close to x & ei!r z above describ$ or else ) ! palm t[>d ! "r1 grasp+ ! tube 9 ! same way z ! "r h& does4 ,?is puts bo? h&s 9 a position :]e ! tube may be bl[n & rotat$ uni=mly :ile its axis is kept horizontal4 ,smoo?ness & exactness are ! two ?+s = :i* ! beg9n] mu/ con/antly /rive 9 glass-bl[+1 & !y are only atta9$ by a c>eful att5tion to ! details ( manipulation1 ) a /eady h& & wat*ful eye4 ,e move mu/ c\nt1 & ! ex]cise mu/ be f9i%$ ) a m9imum ( reheat+ & ret\*+1 = ! be/ results4 ,,*apt] ,,iii ,,elem5t>y ,,ex]cises ,,ex]cise ,,no4 #a ,,jo9+ ,,two ,,pieces ,,( ,,tub+1 ,,end ,,to ,,end--,,fir/ ,,me?od ,?is ex]cise is mo/ easily le>n$ on tub+ ) an ext]ior diamet] ( #a_/d in*1 or a little less1 hav+ mod]ately heavy walls4 ,a piece ( su* tub+ is heat$ be=e ! bl[-pipe at a po9t t5 or twelve in*es f ! end1 & !re drawn out to a capill>y z previ\sly describ$ 7page #i74 ,! capill>y is seal$ (f ab\t two in*es f ! ma9 tube1 & ! latt] is cut ne> ! middle4 ,c>e %\ld be tak5 to get squ>e ends :]e ! cut is made 7page #g74 ,! flame is n[ s regulat$ t x is a little broad] ?an ! diamet] ( ! tube1 ! seal$ half ( ! tube tak5 9 ! left h& & ! o!r half 9 ! "r4 ,! op5 end ( ! seal$ "p & "o ( ! ends ( ! o!r "p are n[ held 9 opposite sides ( ! flame1 incl9$ at a slight angle to "o ano!r z indicat$ 9 ,fig4 #e1 & rotat$ & heat$ until ! surfaces ( bo? ends are j s(t5$4 ,! two ends are !n c>efully & quickly br\ght toge!r 7a1 ,fig4 #f71 remov$ f ! flame & pull$ ap>t a little1 to r$uce ! lump =m$ at ! jo9t z mu* z possible1 z indicat$ 9 b4 ,! jo9t is !n te/$ by bl[+ into ! op5 end ( ! tube to see if x is tight4 ,if s1 ! flame is r$uc$ to half or less ?an half ( its =m] size1 & ! jo9t heat$ 9 x1 hold+ ! tube & cont9ually rotat+ x z direct$ 9 ! la/ *apt] 7page #ac74 ,illu/ration3 ,,fig4 #e4--,s(t5+ ends ( two pieces ( tub+4 ,illu/ration3 ,,fig4 #f4--;,jo9+ two pieces ( tub+ end to end--fir/ me?od4 ,z ! tube s(t5s & t5ds to %r9k1 ! two ends are press$ toge!r a little & ! walls all[$ to ?ick5 slightly1 z 9 c4 ,x is !n quickly remov$ f ! flame & g5tly bl[n z indicat$ 9 d1 cont9u+ ! rotation ( ! tube dur+ ! bl[+1 & at ! same "t press+ ! ends ( ! tube toge!r a little s z to make a %ort ?ick-wall$ bulb4 ,! jo9t is !n return$ to ! flame & reheat$1 rotat+ z be=e1 %r9k+ to ab\t ! %ape ( e4 ,:5 ?is /age is rea*$1 ! glass %\ld be v hot & fluid1 & ! mass ( hot glass ?ick en\gh to rema9 at its work+ temp]ature = ab\t five seconds aft] removal f ! flame4 ,! glass is n[ rebl[n z indicat$ 9 f1 to =m a bulb hav+ walls ( practically ! same ?ickness z ! orig9al tube4 ,z soon z ! bulb is bl[n1 ! tube is remov$ f ! m\?1 held horizontally 9 front ( ! work]1 & g5tly drawn out to =m "o cont9u\s tube1 z indicat$ 9 g4 ,dur+ bo? ! bl[+ & draw+ ( ?is bulb ! rotation mu/ be cont9u$1 & bo? bl[+ & draw+ mu/ be c>efully regulat$ s t ! result+ tube may h ! same int]nal & ext]nal diamet] at ! jo9t z else:]e4 ,discussion4--,9 mak+ ! orig9al jo9t1 7a1 ,fig4 #f71 c>e %\ld be tak5 t ! lump =m$ is z small z possible s t x may be entirely remov$ dur+ ! subsequ5t op]ations4 ,= ?is reason1 only ! v tip ends ( ! two pieces ( tub+ are held 9 ! flame1 & ! s(t5+ %\ld n ext5d m ?an #a_/af in* d[n ! tube4 ,z soon z ! ends are suffici5tly s(t to /ick toge!r1 !y are made to d s4 ,! fir/ draw+ ( ! tube 7b7 %\ld take place imm$iately1 & r$uce ! lump z mu* z possible )\t mak+ ! adjac5t walls ( ! tube ?94 ,! :ole purpose ( ! re/ ( ! manipulation is to absorb or iron out ! lump at ! jo9t4 ,= ?is reason1 c>e is tak5 t ?is lump is always 9 ! c5t] ( ! flame :ile ! jo9t is be+ heat$1 & a small flame is us$ s t little ( ! ma9 tube may be s(t5$4 ,dur+ ! fir/ %r9k+ ( ! jo9t 7c7 ! walls next ! lump1 be+ ?9n] ?an x is1 rea* ! s(t5+ temp]ature fir/ & are ?ick5$ by ! slight pu%+ toge!r ( ! ends1 s t !y tap] f ! lump to ! un*ang$ wall4 ,^u bl[+ ?is jo9t1 ^! ?ick5$ walls bl[ out ) ! lump1 b z !y are ?9ne/ next ! un*ang$ tube1 !y /iff5 !re fir/4 ,!n z ! ?ick] p>ts are /ill hot1 ^! bl[ out m1 & ) ! lump make a m or less uni=m wall4 ,by ?is fir/ op]ation mo/ ( ! lump w h be5 remov$1 provid$ x 0 n too l>ge at fir/1 & ! tube 0 hot en\gh :5 x 0 bl[n4 ,beg9n]s almo/ inv>iably h ! glass too cool "h1 & f9d difficulty 9 bl[+ out a satisfactory bulb4 ,"u su* circum/ances ! lump w be sc>cely affect$ by ! op]ation4 ,dur+ ! %r9k+ ( ?is bulb1 ! ?9n] p>ts ( c\rse are ! fir/ to rea* ! s(t5+ po9t1 & ?us contract m ?an ! ?ick p>ts1 s t practically all ( ! lump c be absorb$1 & a uni=mly ?ick5$ "p ( ! tube left z 9 e4 ,:5 ?is is j accompli%$1 ! second bulb mu/ be bl[n dur+ "o or two seconds1 & ! tube !n drawn out z describ$1 s z to *ange ! bulb to a tube4 ,! draw+ mu/ proce$ ) c>e3 portions ne>e/ ! un*ang$ tubes are ! fir/ to rea* ! prop] diamet]1 & mu/ be giv5 "t to j set at t po9t be=e ! c5t] ( ! bulb is f9ally drawn into %ape4 ,! draw+ is p]haps be/ done int]mitt5tly 9 a s]ies ( quick pulls1 ea* draw+ ! tube p]haps #a_/af in*1 & ea* tak+ place z ! ?umbs & fir/ f+]s grasp ! tube = a new turn 9 ! rotation4 ,if ! tube is n rotat$ dur+ ! bl[+1 ! bulbs w be lop-sid$ & x w be impossible to get a jo9t ( uni=m wall-?ickness2 if rotation is omitt$ dur+ ! draw+1 ! tube w almo/ inv>iably be q crook$4 ,if ! lump /ill %[s di/9ctly aft] ! op]ations describ$1 ! cross-section ( ! tube w be z 9 h1 & ! tube w be likely to break if ev] reheat$ at ?is po9t aft] x becomes cold4 ,! op]ations d1 e1 f1 & g may be repeat$ ^u x1 & x may be possible to get x to come out all "r4 ,c>e mu/ be tak5 n to bl[ ! bulbs d & f too ?9 z !y !n become v difficult to h&le1 & ! jo9t is usually spoil$4 ,! wall-?ickness ( ^! bulbs mu/ nev] be mu* less ?an t ( ! orig9al tube4 ,if ! jo9t z complet$ has ?9n] walls ?an ! re/ ( ! tube1 x w be m easily brok54 ,x %\ld be rememb]$ t ! l5g? ( ! f9i%$ tube mu/ be exactly ! same z t ( ! orig9al piece1 if ! walls ( ! jo9t are to be ( _! orig9al ?ickness4 ,!re=e ! pu%+ toge!r dur+ ! two op]ations c & d mu/ %ort5 ! tube j z mu* z ! f9al draw+ 7f to g7 l5g!ns x4 ,! int]val betwe5 ! removal ( ! "w f ! flame & ! beg9n+ ( ! bl[+ mu/ be made z %ort z possible1 or else ! portions next ! ma9 p>ts ( ! tube w set be=e !y c be bl[n out1 & cause irregul> %runk5 areas4 ,,ex]cise ,,no4 #b ,,jo9+ ,,two ,,tubes ,,end ,,to ,,end--,,second ,,me?od ,! me?od describ$ 9 ,ex]cise ,no4 #a is v satisfactory = jo9+ %ort l5g?s ( /raight tub+1 b becomes inconv5i5t or impossible :5 ! pieces are long or b5t1 on acc\nt ( ! difficulty 9 uni=mly rotat+ su* "w4 ,9 su* cases1 ?is second me?od is us$4 ,x does n usually give z smoo? & pretty a jo9t z ! fir/ me?od1 & takes a little long]4 ,! jo9t is begun exactly z 9 ! fir/ me?od1 & ! manipulation is ! same until aft] ! prelim9>y tight jo9t 7b1 ,fig4 #f7 is made4 ,! flame is r$uc$ z usual1 b in/ead ( rotat+ ! tube 9 ! flame1 only "o "p ( ! circumf]5ce is heat$1 & ?is is all[$ to %r9k ?or\ghly be=e bl[+4 ,x is !n bl[n g5tly s t x becomes a slight swell+ on ! tube1 & ! op]ation repeat$ on an adjo9+ "p ( ! jo9t4 ,?ree or f\r repetitions ( ! op]ation w usually cov] ! :ole circumf]5ce ( ! jo9t1 9 a small tube1 ! result be+ a swell+ r\ghly simil> to ! fir/ ?ick bulb 9 ! fir/ me?od 7d1 ,fig4 #f74 ,if all ! lumps ( ! orig9al jo9t h n be5 remov$ by ?is op]ation1 x may n[ be repeat$ ^u su* p>ts z may require x4 ,! ?ickness ( ! wall 9 ! bulb %\ld be ab\t ! same z t 9 ! orig9al tube4 ,! :ole ( ! exp&$ jo9t is n[ heat$ z uni=mly z may be until s(t en\gh s t x beg9s to %r9k a little1 & ! swell+ is g5tly drawn d[n to ! same diamet] z ! ma9 tube1 z 9 ! fir/ case4 ,any irregul>ities 9 ! f9i%$ jo9t may be correct$ by local reheat+1 %r9k+ or bl[+ z requir$4 ,discussion4--,9 us+ ?is me?od1 especially ) l>g] sizes ( tub+1 x is v important to keep ! :ole circumf]5ce ( ! jo9t hot en\gh dur+ ! op]ation s t x does n crack ap>t at ! "p :i* has n yet be5 work$4 ,= t reason ! fir/ heat+1 %r9k+ & bl[+ %\ld be p]=m$ z quickly z possible1 leav+ ! result+ irregul>ities to be correct$ lat]1 r ?an attempt+ to rebl[ ! same "p ( ! jo9t sev]al times 9 succession until x is satisfactory4 ,c>e mu/ be tak5 9 ?is z 9 ! fir/ me?od t ! bl[+ foll[s imm$iately ^u ! completion ( ! %r9k+ & removal ( ! object f ! flame3 delay 9 bl[+ w cause %runk5 places :]e ! jo9t meets ! orig9al tubes1 on acc\nt ( ! cool+ & sett+ ( ! glass be=e x 0 bl[n4 ,mo/ beg9n]s err 9 be+ afraid to %r9k ! "p ( ! jo9t en\gh be=e bl[+ x4 ,on small tub+1 ! %r9kage may (t5 ext5d s f> t ! inn] surface ( ! %runk5 "p rea*es ! c5t] ( ! tube4 ,insuffici5t %r9k+ results 9 failure to remove ! lump =m$ at ! orig9al jo9t4 ,x is (t5 ( advantage1 aft] bl[+ out "p ( ! jo9t1 to all[ t "p a few seconds to set be=e go+ on ) ! re/1 keep+ ! :ole jo9t w>m mean:ile 9 or ne> ! smoky flame4 ,?is helps to prev5t ! twi/+ ( ! jo9t1 or o!r di/ortion incid5t to ! h&l+ ( a piece ( "w ( awkw>d %ape4 ,9 mak+ a jo9t on a v long or heavy piece by ?is me?od1 x is (t5 advantage\s to atta* a piece ( rubb] tub+ to ! op5 end1 hold ! o!r end ( ?is tub+ 9 ! m\? dur+ ! process1 & bl[ ?r\gh x1 r ?an attempt to br+ ! end ( ! glass up to ! m\?4 ,?is enables "o to keep clos] wat* on ! jo9t1 & avoid draw+ x out or di/ort+ x 9 h&l+4 ,on ! o!r h&1 ! rubb] tube is an inconv5i5ce on acc\nt ( its weight & ! consequ5t pull on ! end ( ! app>atus1 & makes rotation difficult4 ,,ex]cise ,,no4 #c ,,! ,,tee ,,tube ,! op]ations involv$ are two3 ! bl[+ ( a %ort side tube on a piece ( tub+1 & seal+ ano!r piece ( tub+ on ?is1 by :at is ess5tially ! second me?od z j describ$4 ,illu/ration3 ,,fig4 #g4--,! tee tube4 ,! two pieces ( tub+ to be us$ ea* h "o end cut squ>e & ! o!r seal$ 9 ! usual mann]4 ,! long] ( ! two is n[ heat$ at ! po9t at :i* ! jo9t is to be made1 until x beg9s to color ! flame4 ,a small flame is us$1 & ! tube rotat$ until ! flame beg9s to be color$1 :5 ! rotation is /opp$1 & only "o spot heat$ until a spot ! diamet] ( ! tube to be seal$ on has become r$ hot & begun to %r9k4 ,?is is n[ g5tly bl[n out into a small bulb1 z 9 a1 ,fig4 #g1 & x w be not$ t ?is bulb w h walls tap]+ f ! ?ick walls ( ! tube to a v ?9 wall at ! top4 ,! sides ( ?is bulb1 bel[ ! dott$ l9e1 are to =m ! small side tube to :i* ! ma9 side tube is to be seal$4 ,! top ( ! bulb is n[ s(t5$ by direct+ a small flame directly ^u x1 & z soon z x %r9ks to ! level indicat$ by ! dott$ l9e1 x is remov$ f ! flame & quickly bl[n out to =m a ?9 bulb1 z indicat$ 9 b1 ,fig4 #g4 ,?is w usually be s v ?9 t a /roke ( ! file or glass-knife w break x (f at ! dott$ l9e1 leav+ ! side tube1 to :i* ! %ort piece ( tub+ is n[ seal$ accord+ to ! second me?od 7,ex]cise ,no #b74 ,9 do+ ?is1 c>e is tak5 to direct ! flame p>tly on ! ma9 tube 9 ! two crot*es1 s t bo? tubes bl[ out a little & give space = ! gases to turn 91 z indicat$ 9 c1 ,fig4 #g1 & at ! same "t increase ! me*anical /r5g? ( ! job4 ,on ! o!r h&1 c>e is tak5 n to de=m ! ma9 tube1 & n to produce su* a bulge or bulb at ! jo9t z w prev5t ! f9i%$ tube f ly+ flat on a table4 ,discussion4--,mo/ beg9n]s t5d to err 9 ! fir/ /eps ( ?is op]ation1 by bl[+ too h>d & too long :5 bl[+ out ! little bulb4 ,! result is a l>ge1 v ?9 bulb1 :i* breaks (f 9 su* a way z to leave a hole 9 ! ma9 tube1 occupy+ ne>ly half ! circumf]5ce ( ! tube at t po9t1 in/ead ( ! neat side tube :i* !y %\ld h4 ,x is n difficult to seal a tube on ?is side tube1 b x is v difficult to seal a tube into a hole 9 ano!r tube4 ,c>e %\ld be tak5 "h1 z 9 ! two previ\s ex]cises1 t ! lump obta9$ at ! jo9t :5 ! two tubes are put toge!r is made z small z possible1 & r$uc$ if possible by g5tly draw+ on ! side tube z soon z ! tubes h actually jo9$4 ,x is mu* easi] to prev5t ! =mation ( a lump at ! jo9t ?an x is to remove ! lump aft] x is =m$4 ,! rem>ks previ\sly made ab\t bl[+ quickly aft] remov+ ! "w f ! flame apply "h ) especial =ce4 ,a tee tube1 f its v nature1 is expos$ to a good _m /ra9s1 s c>e mu/ be tak5 t ! walls ( ! jo9t are ( uni=m ?ickness ) ! re/ ( ! tube4 ,! beg9n] w f9d x easie/ to make ?is tube out ( two pieces ( ! same tube1 ab\t #a_/d in* 9 diamet]4 ,l>g] or small] tub+ is usually m difficult4 ,if tub+ mu* m ?an #a_/d in* is us$1 ! :ole jo9t1 includ+ "p ( ! ma9 tube1 mu/ be heat$ ne>ly to ! s(t5+ po9t at ! close ( ! op]ation1 & well anneal$1 z describ$ 9 ,*apt] #a 7page #c7 or x w be almo/ c]ta9 to crack4 ,9 ! l>g] sizes ( tube x w be necess>y to heat ! :ole circumf]5ce ( ! ma9 tube frequ5tly dur+ ! op]ation1 to prev5t x f crack+4 ,9 seal+ a small tube on ! side ( a l>ge "o1 x is usually advisable1 aft] w>m+ ! spot :]e ! jo9t is to be made1 to atta* a small drop ( glass to ! tube at t po9t1 & direct ! flame ^u t1 ?us supply+ at ! same "t bo? a def9ite po9t to be heat$ & an extra supply ( glass = ! little side tube :i* is desir$4 ,9 ?is way x is also easi] to bl[ out a side tube ) a suffici5tly small diamet]4 ,if ! diamet] ( ?is tube %\ld be mu* great] ?an t ( ! small tube1 ! latt] may be enl>g$ ) a c>bon or a flang+ tool4 ,,ex]cise ,,no4 #d ,,to ,,jo9 ,,two ,,tubes ,,( ,,diff]5t ,,diamet]s ,9 ?is case ! fir/ me?od 7,ex]cise ,no4 #a7 is to be us$ :5ev] possible1 z x gives a mu* smoo!r jo9t ?an ! second me?od4 ,! directions giv5 w describe ! adaptation ( ?is me?od to ! problem3 if ! second me?od mu/ be us$ on acc\nt ( awkw>d %ape1 etc41 ( ! "w1 ! modifications requir$ w be obvi\s to any "o :o has le>n$ to make ! jo9t by ! fir/ me?od4 ,aft] seal+ or cork+ "o end ( ! l>g] tube1 ! o!r end is drawn out to =m a tail z describ$ on page #i1 tak+ c>e to h ! tube uni=mly heat$1 & to draw ! tail rapidly en\gh s t ! cone is %ort1 z indicat$ 9 a1 ,fig4 #h4 ,! tube is n[ rotat$1 a small flame direct$ aga9/ ! cone at "r angles to an elem5t ( x1 & x is all[$ to %r9k a little1 z indicat$ 9 b1 ,fig4 #h1 s t its walls w ?ick54 ,:5 ! tail is cut (f1 at ! dott$ l9e1 ! diamet] ( ! op5+ & ! ?ickness ( ! walls at t po9t %\ld correspond ) ! dim5sions ( ! tube to be seal$ on4 ,z ! glass is hot1 ! scrat* = cutt+ x mu/ be made ) a file 7moi/5 ! edge671 & x (t5 w n break squ>e across4 ,be=e proce$+ to seal on ! small tube1 any l>ge projections on ! cut end are be/ remov$1 by w>m+ ! cut surface a little1 direct+ ! small flame ^u ea* projection 9 turn & t\*+ x ) a w>m scrap ( glass4 ,x w adh]e to ?is & may !n be remov$ by rotat+ ?is scrap a little s z to w9d up ! projection on x1 & !n draw+ x (f1 :ile ! flame is /ill play+ on ! spot4 ,?is mu/ be done rapidly & c>e tak5 n to s(t5 ! ma9 "p ( ! cone4 ,illu/ration3 ,,fig4 #h4--;,jo9+ two tubes ( diff]5t diamet]s4 ,! l>ge tube is n[ tak5 9 ! left h&1 ! small "o 9 ! "r1 ! ends heat$ & jo9$ 9 ! usual mann]1 tak+ c>e n to get any l>g] lump at ! jo9t ?an necess>y4 ,a small flame is n[ direct$ on ! cone at "r angles to its elem5ts z be=e1 & ! tube rotat$ s z to heat ! :ole circumf]5ce4 ,! flame %\ld be j l>ge en\gh to heat ! :ole ( ! cone4 ,z ! latt] %r9ks1 ! lump at ! jo9t is br\ght into ! edge ( ! flame1 & x & a v little ( ! small tube all[$ to %r9k ) ! cone4 ,:5 well %runk & heat$ to bl[+ temp]ature ! jo9t is remov$ f ! flame & bl[n g5tly ) c>eful rotation1 pu%+ ! tubes toge!r a little :5 ! bl[+ is ab\t f9i%$1 s t ! cone becomes a %ort ?ick half-bulb1 z %[n 9 d1 ,fig4 #h4 ,?is corresponds to ! fir/ ?ick bulb 9 ! fir/ me?od 7d1 ,fig4 #f71 & is treat$ simil>ly4 ,x is aga9 heat$ & %runk1 tak+ c>e n to involve ei!r ! l>ge tube or ! small "o 9 ! %r9k+1 bl[n quickly to ab\t ! same %ape z be=e1 7d1 ,fig4 #h71 & !n g5tly drawn out into a smoo? cone 7e71 exactly z 9 ! fir/ ex]cise4 ,c>e %\ld be tak5 n to draw too rapidly or too f>1 z !n ! result+ cone 7f7 is weak] ?an x %\ld be1 & does n look well4 ,discussion4--,! beg9n] w f9d t ?is op]ation is be/ le>n$ on two tubes :i* are n too ne>ly ( ! same diamet]4 ,a tube ab\t #e_/h in* 9 diamet] & "o a little less ?an #a_/d in* w be suitable4 ,bo? %\ld h mod]ately heavy walls 7#a_/af in* or a trifle ov] = ! l>ge tube1 & a trifle less = ! small "o7 b ! l>ge tube %\ld n be too heavy or else x w be h>d to prev5t melt+ d[n too mu* ( ! small tube1 & gett+ ?is drawn out too ?9 dur+ ! process4 ,"o ( ! tr\blesome features ( ?is ex]cise is ! difficulty ( rotat+ two tubes ( diff]5t diamet]s ) ! same angul> velocity1 s z n to twi/ ! jo9t4 ,ano!r difficulty is f\nd 9 gett+ ! cone uni=mly heat$ to bl[+ temp]ature )\t ov]heat+ & ov]%r9k+ ! small tube4 ,! reason = ?is is obvi\sly ! mu* great] circumf]5ce ( ! cone1 especially at its l>ge end1 s t relatively mu* less ( x is be+ heat$ at any "t4 ,! beg9n] is also incl9$ to />t ) too long a cone1 or else heat s mu* ( ! l>ge tube t "p ( its glass is includ$ 9 ! cone1 ) ! result t 9 ord] to get ! "r wall-?ickness ! cone mu/ be made too long 7g1 ,fig4 #h74 ,?is does n look well1 & usually w be irregul> 9 %ape4 ,,ex]cise ,,no4 #e ,,tube ,,= ,,cond5s+ ,,sulphur ,,dioxide ,?is is useful z a te/ ( ma/]y ( ! prec$+ ex]cise4 ,a piece ( #c_/af or #g_/cb in* tub+ is jo9$ to ea* end ( a piece ( tub+ #e_/h by ab\t #e in*es1 & two con/rictions made 9 ! l>ge tube1 by ! me?od describ$ on page #aj4 ,! small tubes are !n b5t 9 ! same plane1 z %[n1 & _! ends fire-poli%$ 7,fig4 #i74 ,illu/ration3 ,,fig4 #i4--,tube = cond5s+ sulphur dioxide4 ,,ex]cise ,,no4 #f ,,bulb ,,at ,,! ,,end ,,( ,a ,,tube ,= ?is ex]cise tub+ ( #a_/d in* diamet] & mod]ately /rong walls is select$4 ,a tail is drawn out on "o end ( ! tube1 & a piece ( tub+ ab\t n9e or t5 in*es long is cut (f4 ,! tail %\ld be c>efully drawn 9 ! axis ( ! tube1 & 9 ! same /raight l9e ) x1 z x is to be us$ z a h&le 9 assembl+ ! glass = ! bulb4 ,?is tail mu/ be long en\gh s t x c be conv5i5tly held 9 ! left h&1 z describ$ on page #ac1 & rotat$ ab\t ! same axis z ! ma9 tube4 ,hold+ ! ma9 tube 9 ! "r h& & ! tail 9 ! left1 ! tube is rotat$ 9 a l>ge flame s t a piece ( x1 beg9n+ :]e ! tail /ops & ext5d+ ab\t an in* to ! "r1 may be uni=mly heat$ to ! highe/ temp]ature at :i* x c be kept 9 %ape4 ,z soon z ?is temp]ature is rea*$1 ! tube is remov$ f ! flame1 cont9u+ ! rotation & tak+ c>e n to draw out ! heat$ "p1 & g5tly bl[n4 ,! rotation is c>efully cont9u$ dur+ ! bl[+1 hold+ ! tube 9 approximately a horizontal position4 ,z soon z ! tube has exp&$ a little ! tail is pu%$ g5tly t[>d ! ma9 tube1 cont9u+ ! g5tle bl[+4 ,if ?is is prop]ly done1 ! heat$ piece ( tube w become a %ort bulb ( ab\t d\ble its orig9al diamet]1 & ab\t ! same wall ?ickness z ! orig9al tube4 ,x w h some:at ! appe>ance ( a1 ,fig4 #aj1 :5 prop]ly manipulat$4 ,illu/ration3 ,,fig4 #aj4--;,bl[+ a bulb on ! end ( a tube4 ,! tube is n[ reheat$ z be=e1 tak+ c>e ?is "t t ! heat+ ext5ds ov] all t "p ( ! bulb to ! "r ( ! dott$ l9e 9 ! figure1 z well z "p ( ! ma9 tube adjo9+4 ,if ?is heat+ has be5 prop]ly plac$1 :5 ! op]ation ( bl[+ & pu%+ toge!r is repeat$ ! result w be to l5g!n ! bulb into a uni=m cyl9d]1 z %[n 9 b1 ,fig4 #aj4 ,o!rwise ! result w be a s]ies ( bulbs1 z 9 c1 ,fig4 #aj1 sep>at$ by ?ick5$ ridges :i* w be almo/ impossible ( removal lat] & w disfigure ! f9al bulb4 ,?is op]ation ( heat+1 bl[+ & pu%+ toge!r is repeat$ sev]al times1 until ! cyl9d] becomes z long z c be conv5i5tly h&l$ 7ab\t #a-a_/d in*es to #a-a_/b in*es74 ,if m glass is ne$$ ?an is !n conta9$ 9 ! cyl9d]1 ! latt] may n[ be heat$ z a :ole1 & bl[n & pu%$ g5tly into a %ort] cyl9d] ( a slightly great] diamet]1 & m glass !n add$ z be=e4 ,:5 en\gh glass has be5 collect$ = ! bulb1 x is all well heat$ & bl[n g5tly a c\ple ( times1 pu%+ ! mass toge!r z requir$1 until a ?ick bulb l d1 ,fig4 #aj1 is obta9$4 ,! tail mu/ n[ be remov$ at ! po9t indicat$ by ! dott$ l9e4 ,to d ?is1 a v f9e flame is direct$ on ! po9t :]e ! tail jo9s ! bulb1 & ! tube well rotat$ z ! glass s(t5s at t po9t4 ,:5 suffici5tly s(t1 ! "w is rais$ a little1 s t ! flame in/ead ( /rik+ ! glass squ>ely at ! po9t indicat$ passes bel[ & tang5tial to x4 ,! tail is n[ drawn (f sl[ly1 cont9u+ ! rotation1 rais+ ! "w j out ( ! flame :5ev] ! ?read ( glass drawn (f becomes too ?91 & l[]+ x aga9 to ! po9t :]e ! flame j t\*es x :5 ! glass /iff5s a little4 ,by ?is means ! tail may be drawn (f )\t leav+ an appreciable lump beh9d1 z indicat$ 9 e & f1 ,fig4 #aj4 ,:5 z mu* ( ! extra glass has be5 remov$ z is practicable1 ! flame is br\ght to play squ>ely ^u ! little lump left1 ! la/ ( ! tail remov$1 & ! lump heat$ & g5tly bl[n to a small excresc5ce on ! ma9 bulb4 ,! :ole end ( ! latt] is n[ heat$ until x beg9s to %r9k a little1 & g5tly bl[n to make x uni=m 9 ?ickness4 ,! :ole bulb is !n heat$ 9 a flame ( ! prop] size1 s t x all may %r9k to ab\t two-?irds ( its diamet]4 ,! flame mu/ be v c>efully *os5 & direct$1 s z to %r9k all ! bulb1 "r up to ! ma9 tube1 b n s(t5 ! latt]4 ,z soon z ?is /age is rea*$1 ! bulb is remov$ f ! flame1 cont9u+ ! ev5 rotation1 & bl[n to ! desir$ size1 pref]ably by a s]ies ( g5tle puffs foll[+ "o ano!r at v %ort int]vals4 ,dur+ ! bl[+1 ! ma9 tube is held 9 a horizontal position1 & any t5d5cy ( ! bulb to fall out ( l9e is correct$ by ! rotation4 ,if ! %ape ( ! bulb or its size are n satisfactory1 x may be %runk aga9 & rebl[n4 ,su* %r9k+ %\ld beg9 9 a l>ge yell[ flame1 ) j en\gh air to give x direction4 ,! am\nt ( air may be gradually increas$ z ! bulb %r9ks & ! walls become ?ick en\gh to be> x )\t collaps+4 ,if ! bulb />ts to collapse at any "t1 x mu/ be imm$iately bl[n en\gh to rega9 its convex surface1 be=e ! %r9k+ proce$s fur!r4 ,discussion4--,9 collect+ ! glass = ! bulb1 en\gh mu/ be ga!r$ to give ! walls ! desir$ /r5g?4 ,s9ce ! area ( a sph]e is proportional to ! cube ( its diamet]1 x is evid5t t d\bl+ ! size ( a bulb dim9i%es ! ?ickness ( its walls to a v l>ge ext5t4 ,! limit ( diamet] = a /rong bulb on ord9>y #a_/d-;in* tub+1 collect+ ! glass z above1 is ab\t #a-a_/b in*es1 & ! beg9n] w d well n to bl[ 8 bulbs m ?an an in* 9 diamet]4 ,! collection ( ! glass is "o ( ! mo/ important p>ts ( ! process4 ,if ! mass ( glass be twi/$1 furr[$ or ridg$1 or lop-sid$1 x is v difficult to get a good1 ev51 sph]ical bulb1 no matt] h[ _m times x is %runk & bl[n4 ,! greate/ c>e %\ld !re=e be tak5 to get a uni=m cyl9d]1 on ! same axis z ! ma9 tube2 & to ?is end ! rotation ( ! tube mu/ be c>ri$ on v ev5ly4 ,= me?od ( hold+ ! tube1 see page #ad4 ,if a v l>ge bulb is requir$1 x w (t5 be economical to seal on ! end ( ! tube a %ort piece ( a l>ge tube1 provid$ ) ! prop] tail1 & use ! glass 9 ! l>ge tube = ! bulb in/ead ( attempt+ to collect x f ! small tube4 ,9 ?is case "p ( ! small tube w usually be includ$ 9 ! bulb1 s t ! jo9t comes 9 ! latt]1 & n :]e x jo9s ! tube4 ,z ! am\nt ( glass c>ri$ on ! end ( ! tube increases 9 weight & size ! difficulties ( heat+ x uni=mly1 keep+ x 9 ! prop] position & h&l+ x increase rapidly4 ,9 collect+ glass1 x is usually be/ n to leave ! "p ( ! cyl9d] next ! tube ) too ?ick walls4 ,?is is always ! coole/ "p dur+ ! prep>ation = bl[+ ! bulb1 consequ5tly x does n get bl[n out1 & causes an ugly ?ick5$ appe>ance on t end ( ! bulb4 ,if ! bulb gr[s too long or pe>-%ap$1 x may be easily %ort5$ by heat+ to ! bl[+ temp]ature1 & !n bl[+ g5tly ) ! ma9 tube 9 a v]tical position1 & ! bulb at ! top ( x4 ,gravity w !n %ort5 ! bulb nicely4 ,! f9i%$ bulb %\ld be a ne>ly p]fect sph]e1 ) ! axis ( ! tube pass+ ?r\gh its c5t]1 & ! portion ( ! tube adjo9+ ! bulb mu/ n be di/ort$1 twi/$1 or bl[n out4 ,9 ord] to prev5t ! di/ortion ( ! tube1 c>e mu/ be tak5 t x is nev] heat$ q to its s(t5+ po9t dur+ ! process4 ,,ex]cise ,,no4 #g ,,bl[+ ,a ,,bulb ,,9 ,a ,,tube ,! tube is select$ & "o end clos$ z 9 ! previ\s ex]cise1 b x %\ld be cut a little long]1 say ab\t twelve in*es4 ,beg9n+ at a po9t ab\t f\r in*es f ! clos$ end1 glass is collect$ & bl[n into a ?ick-wall$ bulb1 exactly z 9 ! previ\s ex]cise4 ,great] c>e mu/ be tak51 h[ev]1 t ! cyl9d] collect$ & ?is ?ick bulb are ( uni=m ?ickness & set squ>ely 9 ! axis ( ! tube4 ,in/ead ( remov+ ! tail1 ! bulb mu/ be bl[n 9 ?is case ) bo? pieces ( tub+ atta*$1 & c>e mu/ be tak5 t !y l9e up prop]ly1 i4e41 are 9 ! same /raight l9e1 & t ?is l9e passes z ne> z may be ?r\gh ! c5t] ( ! bulb4 ,! tube is held 9 approximately horizontal position dur+ ! bl[+ ( ! bulb1 z 9 ! previ\s case1 & especial c>e tak5 ) ! rotation4 ,bo? pieces ( tube mu/ ( c\rse be rotat$ at ! same rate1 & _! s(t5$ ends mu/ be kept at exactly ! prop] di/ance f ea* o!r1 s t ! bulb may be sph]ical & n elongat$4 ,if ! bl[+ ( ! bulb be quickly & accurately done1 x may usually be complet$ be=e ! glass is q set1 & ! alignm5t ( ! two tubes may !n be rectifi$ :ile look+ /raight ?r\gh ! bore ( ! tube4 ,discussion4--,! two po9ts ( greate/ importance are ! collection ( ! glass1 & ! uni=m rotation ( ! tube4 ,a l>g] tube may be seal$ 9 ! middle ( a small "o :5 a l>ge am\nt ( glass is necess>y4 ,! piece ( tub+ us$ = ! ex]cise mu/ be long en\gh s t ! f+]s may be kept on a cool "p ( ! glass )\t gett+ uncom=tably ne> ! ends ( ! tube4 ,x %\ld n be any long] ?an necess>y1 h[ev]1 z ! extra weight & l5g? make ! manipulation ( ! hot glass m difficult4 ,:5 a /r+ ( bulbs are requir$ on ! same tube1 a piece ( glass #ah in*es long may be us$ at ! />t1 & ! fir/ bulb made ne> ! clos$ end1 z describ$4 ,ea* succe$+ bulb w !n be 9 pla9 view dur+ ! bl[+1 & :5 ! op5 end becomes too %ort = com=t1 x may be dri$ out1 cut (f1 & ano!r piece jo9$ to x1 />t+ z 9 ! fir/ me?od 7,ex]cise ,no4 #a71 b in/ead ( draw+ out ! ?ick bulb to a tube1 x is made "p ( ! glass collect$ = ! next bulb4 ,if ! /r+ ( bulbs becomes awkw>d to h&le on acc\nt ( its l5g? & weight1 x may be made 9 sev]al p>ts & ^! lat] seal$ toge!r by ! second me?od1 pref]ably bl[+ ?r\gh a rubb] tube atta*$ to ! op5 end1 z describ$ on page #bb4 ,v neat small bulbs may be made on tub+ ( a diamet] ( #c_/af in* or a little less1 b ! beg9n] is advis$ to />t ) tub+ ( ab\t #a_/d in* diamet]4 ,! use ( tub+ ) too ?ick walls usually produces bulbs :i* are ?ick-wall$ at ! po9t :]e !y leave ! tube1 b incl9$ to be too ?9 at ! po9t ( maximum diamet] 7p]p5dicul> to ! axis ( ! tube7 :]e mo/ ( ! /ra9 comes & /r5g? is p>ticul>ly ne$$4 ,,*apt] ,,iv ,,advanc$ ,,ex]cises ,,ex]cise ,,no4 #h ,,seal+ ,a ,,tube ,,?r\gh ,,ano!r ,,tube ,fir/ ,me?od--,mak+ a ,gas-wa%+ ,tube ,?is fir/ me?od c be us$ :5ev] "o c "w ?r\gh an op5 end opposite to ! end ( ! tube :]e ! jo9t is to be made4 ,to illu/rate x1 take a piece ( r ?9-wall$ tub+1 ab\t #c_/d in* 9 diamet]1 & "s pieces ( r /rong tub+ a little less ?an #a_/d in* 9 diamet]4 ,draw (f ! l>ge tube 9 a %ort cone1 !n draw (f ! tail z 9 ! mak+ ( ! bulb on ! end ( ! tube1 bl[ out ! little lump slightly1 %r9k ! :ole cone a little & bl[ g5tly to =m a r\nd$ end l t on a te/-tube1 ) walls ab\t ! ?ickness ( ^? ( ! re/ ( ! tube4 ,cut ?is tube to a suitable l5g?1 say ab\t six in*es1 & provide two corks :i* w fit ! op5 end ( x4 ,n[ cut a piece ( ! small tub+ ( ! prop] l5g? to =m ! piece :i* is to be inside ! l>ge tube4 ,= practice purposes1 ?is piece %\ld be ab\t an in* %ort] ?an ! l>ge tube4 ,flange "o end ( ?is tube a little1 & anneal ! flange well 9 ! smoky flame4 ,bore "o ( ! corks s t a piece ( ! small tub+ w fit x1 & cut a c\ple ( not*es 9 ! side ( ?is cork s t air c pass betwe5 x & ! glass4 ,pass a %ort piece ( ! small tub+ ?r\gh ?is cork1 & atta* ! flang$ piece ( small tube to ?is by means ( a %ort piece ( rubb] tub+1 s t :5 ! :ole is ins]t$ 9 ! l>ge tube x is arrang$ z 9 a1 ,fig4 #aa4 ,! piece ( glass tub+ project+ out ?r\gh ! cork is n[ cut (f s z to leave an end ab\t #a_/b in* long :5 ! cork is firmly seat$ & ! inn] tube pu%$ into contact ) ! c5t] ( ! end ( ! l>ge tube1 z %[n 9 ! draw+4 ,c>e %\ld be tak5 t ! little rubb] tube :i* jo9s ! two pieces is arrang$ z 9 ! figure2 i4e41 mo/ ( x on ! piece ( tub+ :i* passes ?r\gh ! cork1 & v little on ! o!r piece1 s t :5 ! cork is remov$ aft] ! small tube has be5 seal$ ?r\gh ! l>ge "o1 ! rubb] tube may easily come ) x4 ,select a %ort piece ( ! small tub+ ( suitable l5g? = ! piece :i* is to be on ! outside ( ! l>ge tube z a cont9uation ( ! piece inside1 & ano!r piece = ! deliv]y tube4 ,a small bulb may be bl[n 9 ! latt] at a po9t ab\t #b-a_/b in*es f ! clos$ end1 & ! op5 end cut (f ab\t #a-a_/b in*es f ! bulb4 ,a cork or cork-bor+ ( suitable size to /opp] ! small tube is prep>$1 & laid ready ) ! o!r 7unbor$7 cork = ! l>ge tube4 ,illu/ration3 ,,fig4 #aa4--;,gas-wa%+ tube4 ,:5 ev]y?+ is 9 read9ess1 ! r\nd$ end ( ! l>ge tube is sl[ly heat$ until x s(t5s & jo9s firmly to ! small tube inside4 ,aft] x has %runk d[n well1 x is bl[n out to its orig9al size1 plac+ ! :ole end ( ! l>ge tube1 cork & all1 9 ! m\?4 ,n[ ) a f9e-po9t$ flame ! glass cov]+ ! end ( ! small tube is heat$ to ! s(t5+ temp]ature1 & !n is bl[n out to an excresc5ce by bl[+ on ! end ( ! small tube :i* passes ?r\gh ! cork4 ,! end ( ?is excresc5ce is heat$ & bl[n (f 9 ! usual way1 s z to leave ! small tube seal$ on ! inside ( ! l>ge "o & op5+ ?r\gh x into ?is %ort tube :i* has be5 bl[n out4 ,! end ( ! small tube :i* passes ?r\gh ! cork is n[ clos$ ) ! cork prep>$ = x1 & ! %ort out] tube is jo9$ to ! tube t has j be5 bl[n out1 s t ! jo9t appe>s l b1 ,fig4 #aa4 ,use ! fir/ me?od 7,ex]cise ,no4 #a7 = ?is jo9t4 ,reheat ! :ole ( ! end ( ! tube ne>ly to ! s(t5+ temp]ature1 anneal x a little1 & all[ to cool a few seconds until well set4 ,n[ remove ! cork1 %ort glass tube & rubb] tube f ! op5 end ( ! l>ge tube & ins]t ! solid cork 9 _! place4 ,w>m ! jo9t & ! :ole ( t end ( ! tube aga9 c>efully up to ab\t ! s(t5+ po9t1 !n seal on ! side tube = ! deliv]y ( ! gas 9 ! usual way1 tak+ c>e t ! :ole ( ! end & ! jo9t are kept w>m mean:ile4 ,:5 ?or\ghly seal$1 ! deliv]y tube is b5t up p>allel to ! tube ?r\gh :i* ! gas ent]s1 & !n out at "r angles to x1 z %[n 9 c4 ,! :ole ( ! end ( ! tube is n[ cauti\sly reheat$ & !n cool$ sl[ly to anneal x4 ,! cork may n[ be remov$ f ! op5 end ( ! l>ge tube1 ?is end heat$ 9 a l>ge flame1 caught toge!r ) a scrap ( glass tub+ & drawn (f into a cone s t ! base ( ! cone is ab\t opposite ! end ( ! inn] tube4 ,! lump ( glass is drawn (f ! po9t ( ?is cone & x is rebl[n to =m a r\nd$ end1 z previ\sly describ$4 ,aft] ?is cools1 ! tube ?r\gh :i* ! gas ent]s may be heat$ at ! prop] po9t & b5t at "r angles to =m ! f9i%$ app>atus z %[n 9 d4 ,! ends ( ! small tube are cut (f squ>e & fire-poli%$4 ,discussion4--,aft] ! jo9t has once be5 made1 great c>e mu/ be tak5 t x is kept hot dur+ all ! subsequ5t manipulations1 & if x becomes some:at cool at any "t x mu/ be reheat$ v sl[ly4 ,x is obvi\s t ! rate ( heat+ & cool+ ( ! inn] tube w be sl[] ?an t ( ! out] tube1 & ?is w readily produce /resses :i* t5d to crack ! tube at ! jo9t4 ,! am\nt ( heat+ & cool+ :i* su* a jo9t w /& dep5ds ^u its =m4 ,! beg9n] %\ld exam9e su* a jo9t on regul> factory-made app>atus1 & note ! uni=mity ( wall-?ickness & ! clean-cut appe>ance ( ! jo9t1 z a model = 8 imitation4 ,a ragg$ jo9t1 :]e ! l9e ( jo9+ ( ! inn] & out] tubes wav]s in/ead ( go+ squ>ely ar\nd ! tube1 is almo/ sure to crack dur+ ! cool+ & heat+ unless extra precautions are tak5 ) x4 ,! pres5ce ( a small lump ( glass at any po9t on ! jo9t af=ds an excell5t />t+ place = a crack1 z d also ! po9ts on a ragg$ jo9t :]e ! inn] tube comes f>!r d[n on ! out] tube ?an at o!r po9ts4 ,9 ord] to insure a jo9t :i* is squ>e & n ragg$1 x is ess5tial t ! angle betwe5 ! inn] & out] tubes at ! jo9t be v ne>ly a "r angle4 ,= ?is reason ! two tubes %\ld n be ( too ne> ! same size1 or if ?is _c be avoid$1 a small bulb %\ld be bl[n on ! end :]e ! jo9t is to be made4 ,if ?is bulb be made ) ! same wall-?ickness z ! re/ ( ! tube1 & some:at pe>-%ap$1 x may be drawn out to ! same size z ! re/ ( ! tube1 if necess>y1 aft] ! jo9t has be5 made4 ,?is me?od is us$ :]ev] possible 9 pref]5ce to ! second me?od 7,ex]cise ,no4 #i71 z x is easi] to get a good jo9t ) x4 ,x may also be us$ :]e x is desir$ to seal ! tube ?r\gh ! side ( a tube1 or = a tube seal$ ?r\gh ! wall ( a bulb1 z 9 a ,geissl] pota% bulb or simil> app>atus4 ,:]e !re is n space to jo9 ! inn] tube to ! bl[+ tube by a rubb] tube1 ?is jo9t may be made ) a small piece ( gumm$ pap]1 :i* c readily be brok5 :5 desir$4 ,,ex]cise ,,no4 #i ,,seal+ ,a ,,tube ,,?r\gh ,,ano!r ,,tube ,second ,me?od--,mak+ a ,suction ,pump ,select a piece ( tub+ #c_/h to #a_/b in* 9 diamet]1 ) walls ab\t #a_/af in* or a little less 9 ?ickness1 heat a place ab\t #d in*es f "o end & draw x out s t :5 cut (f at ! prop] po9t x w look l a1 ,fig4 #ab2 ! op5 end ( ! drawn out "p be+ small en\gh to slip inside ano!r piece ( ! orig9al tube4 ,a small ?ick-wall$ bulb is n[ bl[n z indicat$ by ! dott$ l9es1 & anneal$4 ,a piece ( ! orig9al tub+ is n[ prep>$1 #g or #h in*es long1 ) "o end cut squ>e (f & ! o!r clos$4 ,a piece ( #a_/d-;9 tub+ ab\t #b in*es long1 & drawn out at "o end to a tail sev]al in*es long is also prep>$1 to =m ! inlet tube = ! air4 ,ano!r piece ( ! #c_/h-;in* tube is prep>$1 ab\t #d in*es long1 & provid$ ) a tail drawn out z indicat$ 9 b1 s t :5 cut (f at ab\t #b-a_/b or #c in*es f ! ma9 tube its inn] diamet] may be slightly less ?an t ( ! n>r[e/ po9t ( ! tube a4 ,a small ?ick-wall$ bulb is bl[n at ! po9t indicat$ by ! dott$ l9es1 & anneal$4 ,c>e mu/ be tak5 9 draw+ ! capill>y & bl[+ ! bulb 9 bo? a & b t ! capill>y tubes are 9 ! axis ( ! ma9 tube1 & 9 ! same /raight l9e ) x4 ,illu/ration3 ,,fig4 #ab4--,suction pump4 ,! op5 end ( ! #h-;in* piece ( tube & ! bulb ( ! piece a are n[ w>m$ toge!r1 ! end ( ! tube only mod]ately & ! bulb to ab\t its s(t5+ temp]ature4 ,! tube a is n[ ins]t$ 9 ! op5 end ( ! l>ge tube1 & ! bulb s(t5$ ) a suitable flame & press$ into good contact ) ! tube4 ,x is !n reheat$1 includ+ ! jo9t1 bl[n a little & pull$ out to =m a /raight tube 9 l9e ) ! ma9 tube4 ,by w>m+ ! jo9t a little1 & prop] rotation1 ! capill>y may be br\ght into ! same /raight l9e ) ! re/ ( ! tube4 ,keep+ ?is jo9t hot1 a place ab\t an in* f x on ! tube a is w>m$1 & ! piece ( #a_/d-;in* tub+ previ\sly prep>$ is seal$ on at t po9t4 ,! jo9t is !n well anneal$ & all[$ to cool4 ,! tube a is n[ cut at su* a place t :5 b is ins]t$ 9 ! op5 end ! po9t w come ne> ! end ( ! con/riction ( a1 z %[n 9 c4 ,c>e is tak5 to get a clean squ>e cut4 ,! side tube is n[ cut (f ab\t an in* f ! ma9 tube & cork$4 ,tube b is seal$ into ! op5 end ( a1 9 ! same way z a 0 seal$ into ! l>ge tube1 & ! jo9t c>efully anneal$4 ,discussion4--,z 9 ! fir/ me?od1 ! secret ( success lies 9 gett+ a squ>e jo9t1 & hav+ ! inn] tube leave ! out] "o at ne>ly "r angles4 ,all ! rem>ks ab\t anneal+1 lumps1 etc41 made "u ! previ\s me?od apply "h4 ,?is me?od may be appli$ 9 seal+ a small tube into ! end ( a l>ge "o1 ! latt] be+ ei!r drawn to a cone & cut (f at ! desir$ diamet]1 or else giv5 a r\nd$ end l a te/-tube & a hole ! prop] size bl[n 9 ! c5t] ( x4 ,a suitable ?ick-wall$ bulb is to be bl[n on ! small tube1 z 9 ! case describ$ above4 ,?is me?od is also us$ 9 mak+ ! ,kjeldahl trap 7a1 ,fig4 #ac71 ! small tube to be ins]t$ be+ fir/ drawn1 ! ?ick bulb bl[n at its po9t ( union ) ! ma9 tube1 & !n ! small tube b5t & cut4 ,! l>ge bulb is be/ made ) r heavy wall1 be+ ei!r bl[n 9 ! middle ( a tube1 & "o piece ( ! tube drawn or cut (f1 or else made on ! end ( a tube4 ,9 ! latt] case a drop ( glass mu/ be put on ! po9t :]e ! jo9t is to be1 s z to get a hole ( ! prop] size ) en\gh glass ar\nd x to prev5t x f gr[+ l>g] :5 x is heat$4 ,! au?or pref]s to bl[ ! bulb 9 ! middle ( ! tube1 draw (f "o end ( ! bulb1 & bl[ out ! desir$ hole :]e ! tube 0 drawn (f4 ,! :ole bulb mu/ g5]ally be reheat$ & bl[n a little at ! end ( ! process1 & well anneal$4 ,illu/ration3 ,,fig4 #ac4--;a1 ,kjeldahl trap2 b1 suction pump on small] tub+4 ,! suction pump c also be made on #a_/d-;in* tub+1 & "o jo9t sav$ if desir$1 by con/rict+ ! tube to =m ! raceway = ! wat] & air1 z %[n 9 b1 ,fig4 #ac4 7,see page #aj = me?od47 ,b x is m difficult to make a squ>e jo9t on su* small tub+4 ,,*apt] ,v ,,modifi$ ,,me?ods ,,& ,,special ,,op]ations ,,capill>y ,,tub+ ,?is is commonly us$ 9 _m =ms ( app>atus = gas analysis1 & "o is (t5 call$ ^u to jo9 two pieces or to make a tee on x4 ,! me?ods are ne>ly ! same z ) o!r tub+1 except t m c>e & pati5ce are requir$4 ,! "w mu/ be done mu* m sl[ly on acc\nt ( ! ?ickness ( ! walls1 & op5 ends ( ! tube mu/ always be enl>g$ be=e jo9+ !m to any?+4 ,?is is be/ done by c>efully seal+ ! end & !n bl[+1 ) sev]al suitable reheat+s1 to =m a pe>-%ap$ bulb z 9 a1 ,fig4 #ad4 ,! end ( ?is is !n heat$ & bl[n (f1 & ! piece is ready to be jo9$ to ano!r simil> end1 or to a piece ( ord9>y tub+ if desir$4 ,! jo9ts are be/ n bl[n too mu*1 z ?ick walls %r9k v sl[ly4 ,mu* may be done by g5tly pu%+ ! tube toge!r or pull+ x ap>t 9 ! flame1 to remove lumps & irregul>ities4 ,x is necess>y t ! bore ( ! jo9t be approximately t ( ! ma9 tube1 & c>e mu/ be tak5 t ! latt] is n con/rict$ at ! po9t :]e ! jo9t beg9s4 ,illu/ration3 ,,fig4 #ad4--;,capill>y tub+4 ,especial c>e mu/ be tak5 to w>m ! tube sl[ly :5 />t+ & cool x sl[ly :5 ?r\gh1 z ! ?ick walls frequ5tly crack if n c>efully h&l$4 ,= ?is reason ! :ole neighborhood ( ! jo9t mu/ be heat$ some:at s t !re may n be /resses set up betwe5 ! heat$ & unheat$ portions4 ,9 mak+ ! tee 7b1 ,fig4 #ad7 ! inability to bl[ ! jo9t makes itself decid$ly felt1 b if ! side tube is prop]ly enl>g$ z previ\sly describ$1 a good jo9t c be made by alt]nately pull+ & pu%+ on ! end ( ! side tube1 & %r9k+ well4 ,v f9e capill>y tub+ %\ld be bl[n ) a rubb] bulb in/ead ( ! m\?1 s z n to get moi/ure into ! tube4 ,! rubb] bulb may also be us$ to advantage on "s ( ! co>s] capill>y tub+4 ,:5 a bulb is to be jo9$ to a piece ( capill>y tub+1 ! jo9t is pref]ably made be=e bl[+ ! bulb1 & w !n be tak5 up a little way on ! bulb dur+ ! process4 ,c>e mu/ ( c\rse be tak5 n to con/rict ! capill>y2 ! pe>-%ap$ bulb bl[n on ! end 7a1 ,fig4 #ad7 may well ext5d back a little fur!r ?an usual into ! tube s z to prev5t ?is4 ,if a bulb is requir$ 9 ! middle ( a capill>y tube1 ! latt] is usually be/ cut & a piece ( ord9>y tub+ ( suitable size seal$ 9 to provide mat]ial = ! bulb4 ,,glass ,,rod ,jo9ts1 tees1 etc41 9 glass rod are made on ! same pr9ciple z 9 tub+1 except t ( c\rse !y _c be bl[n1 & regul>ity mu/ be obta9$ by accumulat+ a small mass ( uni=mly heat$ glass1 & !n draw+ x to a suitable rod1 on ! same pr9ciple z ,ex]cise ,no4 #a4 ,great c>e mu/ be tak5 9 heat+ & cool+ ?is1 z 9 ! case ( ! capill>y tub+1 & = ! same reasons4 ,by jo9+ pieces side by side1 press+ ) c>bon plates or a plate & a rod1 & o!r suitable manipulations1 /irr]s1 spatulas1 & o!r objects may easily be made f rod1 & its manipulation is relatively easy on acc\nt ( ! fact t "o does n h to worry ab\t ! bore ( ! tube4 ,b ! same g5]al rule ab\t n hav+ ?ick & ?9 spots 9 contact1 & mak+ all *anges 9 diamet] on a tap] if possible in/ead ( abruptly1 applies "h4 ,?ick pieces w cool & contract at diff]5t rates f ?9 ones1 & cracks are likely to develop :]e !y jo94 ,"w :i* has be5 =m$ ) any tool mu/ always be heat$ to ! s(t5+ po9t aft]w>d be=e all[+ x to cool 9 ord] to remove ! /resses caus$ by ! contact ( ! tool ) ! hot glass4 ,:5 x is necess>y to jo9 a piece ( rod to ! side ( a piece ( tub+1 ! end ( ! rod is made v hot :ile ! wall ( ! tube at ! spot desir$ is heat$ to j bel[ ! s(t5+ temp]ature4 ,! rod c !n be press$ into firm union ) ! tube & drawn a little to remove ! excess ( glass )\t de=m+ ! tube4 ,,m5d+ ,,/opcocks ,m5d+ ! ,plug4--,! plug ( ! /opcock occasionally falls out & is brok54 ,if ! break is 9 ! ma9 "p ( ! plug1 no?+ c be done except to se>* = a sp>e plug ( suitable size & gr9d x to fit1 z describ$ bel[4 ,if only ! little cross-piece at ! end is brok5 (f1 x c easily be replac$4 ,9 mo/ ord9>y /opcocks ! plug is solid1 b ! little h&le is holl[4 ,:at has be5 said above reg>d+ c>e 9 heat+ & cool+ glass rod applies ) especial =ce "h4 ,x is usually be/ to w9d ! :ole ( ! plug ) sev]al ?icknesses ( asbe/os cord1 leav+ b>e only ! end :]e ! h&le is to be jo9$4 ,?is dim9i%es ! dang] ( crack+ ! plug by too rapid heat+1 & also makes x m com=table to hold4 ,a piece ( r ?ick-wall$ tub+ ( suitable diamet] is *os51 drawn out s z to h a suitable tap] 7tak+ c>e to heat en\gh ( ! tube s t ! capill>y tail has good wall-?ickness & /r5g?71 & !n a correspond+ tap] is drawn to =m ! o!r side ( ! h&le4 ,! result is %[n 9 ,fig4 #ae1 a4 ,! capill>y tail is n[ heat$ & b5t back to =m a h&le :i* w be 9 ! same /raight l9e z ! axis ( ! plug 7b1 ,fig4 #ae7 & ! ma9 "p ( ! tube drawn (f at ! dott$ l9e1 mak+ a neat seal at t po9t4 ,! brok5 end ( ! plug is n[ sl[ly w>m$ 9 ! smoky flame1 ! heat gradually increas$ by a g5tle /ream ( air f ! bell[s1 & ! po9t at :i* ?is h&le is to be atta*$ f9ally br\ght to ! temp]ature at :i* ! glass fl[s freely4 ,9 ! mean "t1 ! little h&le has be5 w>m$ almo/ to ! s(t5+ po9t4 ,x is n[ quickly pu%$ into place 7c1 ,fig4 #ae71 tak+ c>e t its axis is p>allel to ! hole 9 ! plug1 & !n drawn away f ! plug j en\gh to make a graceful neck in/ead ( ! bulg+ "o indicat$ by ! arr[ 9 ! figure4 ,) a f9e po9t$ flame ! little tail is n[ drawn (f at ! po9t indicat$ by ! dott$ l9e 7c1 ,fig4 #ae7 & ! :ole c>efully anneal$4 ,if necess>y1 ! h&le c be bl[n a little be=e ! tail is remov$4 ,local heat+ & bl[+ at ! po9t :]e ! h&le jo9s ! plug is (t5 necess>y 9 ord] to make a smoo? job4 ,illu/ration3 ,,fig4 #ae4--,/opcock plug4 ,regr9d+4--,?is is sometimes necess>y to make /opcocks tight1 :5 ! gr9d+ has n be5 prop]ly done 9 ! factory4 ,= ?is1 a v little f9e fl\r ( em]y or c>borundum is ! be/ & quicke/4 ,if ?is is n at h&1 "s clean s& may be gr\nd 9 an agate mort>1 & if possible siev$4 ,only mat]ial :i* passes ! #ajj-me% sieve %\ld be us$4 ,x w be gr\nd /ill f9] 9 ! process4 ,= ! f9al poli%+1 a little infusorial e>? or ev5 kaol9 w d4 ,! surface to be gr\nd is moi/5$ ) wat] & du/$ ov] ) a little ( ! abrasive4 ,! plug is n[ ins]t$ 9 ! /opcock1 & turn$ ) a g5tle pressure4 ,?is turn+ %\ld be 9 ! same direction = sev]al revolutions1 !n 9 ! opposite direction = sev]al m revolutions1 etc4 ,z ! abrasive becomes f9] dur+ ! gr9d+1 a little m may be add$ if necess>y4 ,9 g5]al1 only a little gr9d+ w be requir$1 & "o small p9* ( c>borundum or em]y w be ample4 ,! beg9n] usually gr9ds too mu*1 & ) too co>se mat]ial4 ,z ! gr9d+ surface becomes dry1 wat] is add$ drop by drop1 & ! gr9d+ cont9u$ until ! abrasive seems to be r$uc$ to an impalpable p[d]1 mo/ ( :i* has be5 squeez$ out ( ! /opcock4 ,! two surfaces 9 ! /opcock are usually gr9d+ ^u ea* o!r at ?is /age1 & inspection w %[ :e!r ! contact betwe5 !m is uni=mly good4 ,if n1 ! gr9d+ mu/ be cont9u$ ) a little fre% abrasive4 ,if contact appe>s to be good1 ! surfaces are gr\nd toge!r = a little ) practically no abrasive1 s z to poli% !m1 & ! jo9t is !n wa%$ out & te/$4 ,9 gr9d+ 9 a new plug to replace a brok5 "o1 ! plug select$ %\ld h practically ! same tap] z ! seat into :i* x is to be gr\nd1 & %\ld be a v little too l>ge4 ,c>e mu/ be tak5 to s di/ribute ! abrasive mat]ial z to gr9d mo/ly on ! places :]e ! plug fits tightly4 ,seal+ on a ,new ,tube4--,x frequ5tly happ5s t "o ( ! tubes ( ! /opcock is brok5 (f close to ! cock itself1 & a new "o mu/ be jo9$ to ! /ub ( ! old "o4 ,) c>e1 ?is may (t5 be successfully done ev5 :]e ! break is )9 #a_/d in* ( ! /opcock4 ,! fir/ /ep is to clean & dry ! /opcock1 remove ! plug1 cork ! op5 ends ( ! /opcock sleeve & ! o!r tube1 & w9d a c\ple ( lay]s ( asbe/os cord c>efully ov] ! sleeve & ! mo/ ( ! corks :i* close x4 ,a suitable tube1 hav+ z ne> z possible ! same diamet] & wall /r5g? z ! "o brok5 (f1 is select$ & a piece ! desir$ l5g? cut (f4 ,! brok5 end ( ! tube on ! /opcock is n[ squ>$ (f z well z possible1 by cutt+ or by heat+ & draw+ (f ! projections1 & ! new tube seal$ on1 usually ) ! fir/ me?od 7,ex]cise ,no4 #a74 ,if ! break is v close to ! /opcock1 v little reheat+ & bl[+ c be done1 on acc\nt ( ! dang] ( gett+ ! /opcock sleeve out ( %ape1 & ! "w mu/ be heat$ v sl[ly to prev5t crack+4 ,! ma9 reliance is !n plac$ on mak+ a good jo9t :5 ! tubes are br\ght toge!r1 & !n draw+ out ?is jo9t a little1 at once1 to get an ev5 wall4 ,,clos$ ,,circuits ,,( ,,tub+4 ,9 "s pieces ( app>atus clos$ circuits ( circul> or rectangul> %ape are requir$4 ,a simil> problem is involv$ 9 app>atus l ! ord9>y ,soxhlet extractor1 :]e a small tube is jo9$ to ! side ( a l>ge "o1 b5t to =m a siphon1 & atta*$ aga9 to a cont9uation ( ! orig9al l>ge tube4 ,! difficulty 9 all su* cases is to provide = ! contraction tak+ place z ! la/ jo9t cools4 ,if "p ( ! circuit has ! %ape ( ! lett] ,s1 or is a spiral1 ! natural spr+9ess ( ! glass w take c>e ( ?is4 ,if n1 ! side ( ! circuit opposite to ! jo9t & p>allel to x mu/ be heat$ also1 ! two be+ f9ally heat$ toge!r to ! s(t5+ po9t aft] ! jo9t is complet$1 & !n all[$ to cool toge!r4 ,to make ! la/ jo9t1 ! re/ ( ! tube is made 9 approximately ! desir$ =m1 ! two pieces :i* are to be jo9$ to make ! la/ jo9t be+ j en\gh out ( ! desir$ position to all[ !m to pass "o ano!r4 ,! f9al jo9t is pref]ably made 9 ! middle ( a /raight piece ( tube1 n at a tee4 ,! two pieces :i* are to be jo9$ are b5t s z to j pass ea* o!r1 m>k$ at ! "r po9t ) ! glass-knife1 & cut !re1 pref]ably ) a small bead ( hot glass4 ,"o or bo? ( ^! tubes are n[ w>m$ to ! s(t5+ po9t 9 su* a place t ! tubes c be made to meet prop]ly1 & ! two cut ends press$ toge!r4 ,!y are n[ w>m$ 9 ! flame1 & jo9$ toge!r1 ei!r by simultane\sly w>m+ ! opposite side ( ! circuit or "s o!r suitable "p1 s z to all[ ! two ends to be pu%$ toge!r aga9 aft] !y are s(t5$1 or by g5tly t\*+ ! places t d n unite ) a hot bead ( glass1 & us+ ! glass to fill up ! crack :]e ! ends d n q meet4 ,c>e mu/ be tak5 n to leave knots or lumps ( glass 9 ! f9i%$ jo9t1 & ! latt] %\ld be well rebl[n1 & if necess>y left z a small bulb or enl>gem5t1 r ?an h x h too ?ick walls4 ,,spirals ,spirals ( glass tub+ are probably be/ made free-h& be=e ! bl[-pipe1 unless "o has a great _m ( !m to make1 & extreme accuracy is desir$4 ,to beg9 )1 a piece ( tub+ ( ! desir$ size 7say #c_/af in* 9 diamet]7 & a conv5i5t l5g? 7ab\t two feet7 is select$1 "o end clos$1 & a "r-angle b5d made ab\t six in*es f ! clos$ end4 ,hold+ ! clos$ end 9 ! left h& & ! long op5 "o 9 ! "r1 ! spiral is begun4 ,! %ort clos$ end is to be p>allel to ! axis ( ! spiral1 & pref]ably 9 t axis4 ,us+ a mod]ate-siz$ flame1 ( some:at yell[ color1 & tak+ c>e to heat ! :ole circumf]5ce ( ! tube1 ! long op5 end is w\nd little by little into a spiral hav+ ! %ort end a 7,fig4 #af7 z an axis4 ,! b5d at b1 :]e ! tube *anges f ! radius to ! circumf]5ce ( ! circle1 mu/ be r %ort1 b ! tube mu/ n be flatt5$ or con/rict$ "h4 ,especial pa9s is to be tak5 ) ! fir/ turn ( ! spiral 7b to c1 ,fig4 #af71 z ! %ape ( ?is det]m9es ! diamet] ( ! :ole spiral1 & s]ves z a guide = ! re/ ( ! turns4 ,! w9d+ ( ! tube is be/ accompli%$1 aft] a portion has be5 s(t5$1 by sl[ly turn+ ! %ort end a a little ab\t its own axis1 :ile ! long op5 end rema9s :]e x 04 ,?is w9ds ! tube into a spiral1 j z if !re 7 a solid cyl9d] 9 ! c5t] ( x1 & ?is cyl9d] 0 be+ turn$ ab\t its axis1 & 0 w9d+ up ! s(t glass ^u its circumf]5ce4 ,z ! cyl9d] is n actually !re1 ! curve ( ! turns mu/ be c>efully e/imat$ by ! eye1 s t ! spiral may be uni=m & mod]ately smoo?4 ,:5 ! orig9al piece ( tube has be5 us$ up1 ano!r piece is seal$ on to ! op5 end1 & ! op]ation cont9u$ z f> z may be requir$4 ,illu/ration3 ,,fig4 #af4--,mak+ a spiral4 ,,gr\nd ,,jo9ts ,x is sometimes requir$ to jo9 two pieces ( tub+ end to end1 by means ( a gr\nd jo9t4 ,:5ev] possible1 a regul> seal$ jo9t %\ld be us$ in/ead ( ?is gr\nd jo9t1 z x is quick] to make1 & m c]ta9 to be tight4 ,:]e a gr\nd jo9t is necess>y1 h[ev]1 x is be/ made 9 ! conical =m %[n 9 c1 ,fig4 #ag4 ,if ! wall ( ! tube to be us$ is n v ?ick1 x is ?ick5$ by collect+ glass z = a bulb on ! ends ( two tubes 7,ex]cise ,no4 #f71 & draw+ to =m cones ( suitable %ape 7a & b1 ,fig4 #ag7 & ( su* relative sizes t a w slip ab\t half way into b4 ,9 ord] to make a /raight & give x ! prop] angle1 x may be roll$ :5 hot1 ^u a hot plate ( c>bon4 ,bl[+ dur+ ?is roll+ is (t5 helpful to remove depressions4 ,aft] b has be5 drawn to ne>ly ! prop] size & %ape1 x may be smoo!d by ! use ( a small c>bon rod1 held inside x at a slight angle1 or bett] by ! use ( a truncat$ hexagonal pyramid ( c>bon1 ^: edges h ! prop] slant to make ! inside ( ! cone "r4 ,! prop] tap] = bo? ^! cones is ! same z t us$ 9 /opcocks ( simil> size4 ,! hexagonal c>bon c easily be made by c>efully fil+ d[n an electric light c>bon1 & f9ally impregnat+ x ) p>aff9 or beeswax1 & is extremely useful :]ev] a conical surface has to be =m$ f ! inside ( a tube4 ,illu/ration3 ,,fig4 #ag4--;,gr\nd jo9t4 ,! tail is all[$ to rema9 on piece a1 z a sort ( guide 9 gr9d+1 & %\ld !re=e be 9 ! axis ( ! tube & h r ?ick walls4 ,gr9d ) em]y or c>borundum1 z describ$ "u a previ\s head4 7,regr9d+ plug = /opcock47 ,if _m su* jo9ts are to be made1 x w pay to h a little sleeve ( brass made ) ! prop] tap]1 & r\gh d[n ! plug a 9 x to ab\t ! prop] size1 :ile b is r\gh$ d[n by means ( a brass or iron plug hav+ ! same tap]4 ,?is prev5ts excessive gr9d+ ( "o-half ( ! jo9t 9 ord] to remove a defect 9 ! o!r half1 & is ! me?od comm]cially us$ 9 mak+ /opcocks4 ,,seal+ ,,9 ,,plat9um ,,wire ,v (t5 x is necess>y to seal plat9um wire into ! wall ( a tube4 ,pr(essional glass-bl[]s usually use a special sort ( glass 7,e9s*melzglas7 :i* is usually a lead glass1 & is made ( su* composition t x has ! same or practically ! same coeffici5t ( expansion z plat9um4 ,a little globule ( ?is glass is seal$ into ! tube 9 su* a way t x jo9s ! plat9um to ! glass ( ! tube4 ,to d ?is1 ! small globule ( special glass is fus$ on ! plat9um wire at ! prop] po9t & ! tube into :i* ! wire is to be seal$ is heat$ & a small tail drawn out at ! po9t :]e ! wire is to be ins]t$4 ,! lump ( ! special glass %\ld be f #c_/cb to #a_/h in* 9 diamet]1 & ! tail drawn on ! tube %\ld h a slightly less diamet] at ! po9t 7ab\t #a_/h in* or less f ! tube7 :]e x is cut (f4 ,!re are n[ two ways ( seal+ 9 ! wire4 7#a7 ,! wire ) ! globule ( glass is plac$ inside ! tube & ! latt] revolv$ until ! end ( ! wire /icks out ( ! cut tail 7a1 ,fig4 #ah74 ,! latt] is n[ g5tly heat$1 & ! two glass surfaces fus$ toge!r1 tak+ c>e to use only ! end ( ! hiss+ flame1 if ! special glass conta9s lead4 7,see ,*apt] ,i1 page #a47 ,! :ole circumf]5ce ( ! tube is !n heat$ & anneal$ c>efully4 7#b7 ,! end ( ! wire :i* is to be outside ! tube is atta*$ to ! end ( a ?9 scrap ( glass1 by heat+ ! glass & ?ru/+ ! wire into x a v little way4 ,us+ ?is piece ( glass z a h&le1 ! wire is ins]t$ 9 ! cut tail 7b1 ,fig4 #ah7 & ! globule br\ght ne> to ! end ( ! tail4 7,if ! ma9 tube is cold1 x mu/ ( c\rse fir/ be w>m$47 ,) ! end ( ! hiss+ flame1 z 9 ! fir/ me?od1 ! globule ( glass is melt$ & ! end ( ! tail s(t5$4 ,! wire is n[ pu%$ into place1 ! h&le remov$ by heat+ ! end & )draw+ x1 & ! tail reheat$ a little if necess>y to make x %r9k back into l9e ) ! walls ( ! tube4 ,! :ole circumf]5ce ( ! tube is heat$ at t po9t & anneal$ z usual4 ,illu/ration3 ,,fig4 #ah4 ,! use ( ?is special glass is n absolutely necess>y if ! plat9um wire is small 7#a_/d millimet] or less 9 diamet]71 & 9 fact x is (t5 bett] 9 su* cases n to use x1 unless ! app>atus is to be subject$ to a v high vacuum4 ,on small tubes1 especially1 x is undesirable to use ! special glass1 z a lump ( x w usually cause ! tube to crack on cool+4 ,:5 su* glass is n at h& or is n to be us$1 ! proc$ure is alt]$ some:at4 ,! tail :i* is drawn out is v f9e1 hav+ only a suffici5t diamet] s t :5 x is cut (f ! wire c be ins]t$ 9 x4 ,su* a f9e tail is readily made by heat+ a small spot on ! tube1 t\*+ x ) a w>m plat9um wire1 remov+ f ! flame & draw+ out ! tail ) ! wire4 ,aft] cutt+ (f ! tail ! wire is ins]t$ 9 x1 be+ held on a scrap ( glass z 9 ! previ\s case1 & ! wire & tail heat$ until ! latt] %r9ks back into l9e ) ! walls ( ! tube4 ,if too great %r9kage occurs1 ! place may be bl[n out g5tly aft] reheat+4 ,?us ! wire is seal$ ?r\gh ! wall ( ! tube )\t *ang+ ! ?ickness ( ! latt]1 & consequ5tly )\t develop+ undue /resses at t po9t4 ,su* a jo9t mu/ ( c\rse be c>efully reheat$ & anneal$4 ,) f9e plat9um wire !re is v little risk ( ! tube crack+ if c>e is tak5 to avoid =mation ( any lump & to reheat ! :ole circumf]5ce ( ! tube at t po9t4 ,any glass adh]+ to ! end ( ! plat9um wire1 :]e ! scrap ( glass 0 seal$ on = a h&le1 may be remov$ :5 ! glass has cool$ by cru%+ x c>efully ) a pair ( pli]s4 ,,seal+ ,,vacuum ,,tubes ,tubes :i* h be5 evacuat$ usually are seal$ (f :ile !y are /ill connect$ to ! vacuum pump4 ,! connection %\ld be ?r\gh a small1 r ?ick-wall$ tube4 ,:5 ?is is to be seal$1 x is sl[ly heat$ t[>d ! s(t5+ po9t4 ,z ! glass j beg9s to s(t51 ! air-pressure w =ce x 91 & c>e mu/ be tak5 t ! s(t5+ is uni=m ov] ! :ole circumf]5ce ( ! tube4 ,z ! %r9k+ goes on1 ! tube is g5tly drawn out to make a ?ick-wall$ cone at t place1 & ! end is drawn (f z soon z ! tube is seal$4 ,! pr9cipal po9t to be gu>d$ is ! ?ickness ( ! walls ( ! cone1 & uni=m heat+4 ,a ?9 place or a hot place w give way "u ! air-pressure & be suck$ into ! tube4 ,,clos$ ,,tubes ,,= ,,heat+ ,,"u ,,pressure 7,c>ius me?od = det]m9ation ( ! halog5s & sulphur47 ,9 ?is case ! tub+ us$ mu/ h ?ick walls 7usually ab\t #c_/cb in*7 to )/& ! pressure4 ,its ext]nal diamet] is usually ab\t #c_/d in*4 ,"o l5g? w usually make two tubes ( /&>d l5g? = ! cannon furnace4 ,especial c>e mu/ be tak5 9 heat+ & cool+ x on acc\nt ( ! ?ick walls4 ,a l5g? is gradually w>m$ 9 ! c5t]1 f9ally heat$ at t po9t until s(t1 drawn out1 cut ap>t & anneal$4 ,tak+ "o ( ! pieces1 ! cone is c>efully heat$ & %runk1 z 9 ,ex]cise #d1 until its walls are z ?ick z ^? ( ! ma9 tube4 ,a flame ) a little t+e ( yell[ %\ld be us$ = ?is op]ation to prev5t devitrification 7page #b71 z ! ?ick glass %r9ks sl[ly4 ,! tail is n[ drawn (f & ! :ole end heat$ & g5tly bl[n sev]al times to make a r\nd$ end1 l a te/-tube1 ) walls z ?ick z ^? ( ! ma9 tube4 ,?is mu/ be c>efully anneal$4 ,x is m important t ! walls be ?ick ?an t ! end be nicely r\nd$3 x may inde$ be left some:at conical 9 %ape4 ,at a po9t ab\t two in*es f ! op5 end ( ! tube1 x is sl[ly w>m$ & f9ally heat$ to ! s(t5+ po9t4 ,grasp+ ! op5 end ) a pair ( crucible tongs1 x is cauti\sly pull$ out1 a little at a "t1 usually dur+ rotation 9 ! flame1 to make a con/riction ( mod]ate wall-?ickness1 b ( suffici5t int]nal diamet] to admit ! tube conta9+ ! sub/ance4 ,aft] anneal+ ?is1 cool+ & clean+ ! tube1 ! acid & salt are introduc$ 7! =m] by means ( a long-/emm$ funnel7 & ! tube is incl9$ & rotat$ ab\t its axis s t ! acid wets its surface ab\t half way up f ! bottom4 ,! sub/ance is n[ weigh$ out 9 a piece ( ?9-wall$ glass tub+1 clos$ at "o end1 & ab\t two in*es long4 ,incl9+ ! l>ge tube at a suitable angle1 ! small "o is introduc$1 clos$ end fir/1 & all[$ to slide d[n ! walls ( ! l>ge tube until x rea*es ! place :]e ! acid has wet ! tube4 ,"h x w /op1 & if ! tube is kept incl9$ dur+ ! re/ ( ! op]ation x w roll ar\nd inside ! tube at ?is po9t & ?us n get d[n :]e any acid is likely to get into x & produce any pressure by decompos+ x be=e ! op5 end ( ! tube is seal$4 ,n[ ! tube is held 9 an incl9$ position1 tak+ c>e t ! acid does n rea* up to ! sub/ance1 ! con/rict$ portion cauti\sly w>m$ & %runk4 ,x is f9ally %runk & drawn out into a some:at elongat$ cone1 ) walls z ?ick z ! re/ ( ! tube1 & :5 ?is is accompli%$ ! end ( ! cone is seal$ & ! wa/e piece drawn (f4 ,anneal ) great c>e1 & cool 9 su* a position t ! acid _c rea* ! hot glass4 ,! %r9k+ ( ?is cone takes a good deal ( pati5ce1 & is "o ( ! mo/ important p>ts ( ! process4 ,if ! walls are left too ?91 ! tube may bur/ :5 heat$1 & ! :ole labor is lo/4 ,if c>e is tak51 ! same tube c be us$ = a numb] ( det]m9ations1 until x becomes q %ort4 ,,index ,anneal+ glass1 #d1 #bd ,bell[s1 #d ,b5d+ glass1 #h ,bl[+ glass1 #ac1 #ai1 #bj1 #ba1 #bd1 #bi1 #ca ) a rubb] tube1 #bb ,bl[pipe1 #d ,bulb at end ( tube1 #bh 9 middle ( tube1 #cb v l>ge1 #cb ,bulbs1 /r+ (1 #cc ,capill>y tube1 draw+ on l>g] tube1 #i1 #ed tub+1 work+1 #dc ,c>ius me?od1 tubes =1 #ee ,clos$ circuits ( tub+1 #dh tubes1 = heat+ "u pressure1 #ee ,collect+ glass = bulb1 #bi1 #ca1 #cb ,con/rict+ a tube1 #aj ,cry/allization ( glass1 see ,devitrification4 ,cutt+ glass1 #g1 #be ,devitrification1 #a1 #b ,draw+ out a tube1 #i1 #ah1 #ai1 #bg ,flang+ a tube1 #aa1 #ad tool1 #aa ,gas-wa%+ tube1 #ce ,glass1 anneal+1 #d1 #bd ,glass1 b5d+1 #h bl[+1 #ac1 #ai1 #bj1 #ba1 #bd1 #bi1 #ca collect+ = bulb1 #bi1 #ca1 #cb cutt+1 #g defects1 #b gr9d+1 #dg h>d1 #a knife1 #g lead1 #a qualities desir$1 #a rod & tube1 jo9+1 #de rod1 work+1 #dd %r9k+1 #ah1 #ai1 #bb1 #bf s(t1 #a work+ temp]ature1 #a1 #ac1 #ai1 #bg ,gr9d+ /opcock or jo9t1 #dg ,gr\nd jo9ts1 #ea ,h&le on /opcock1 m5d+1 #de ,h>d glass1 #a ,hold+ tube1 #ac1 #ad ,ins]tion ( tube ?r\gh ano!r1 see ,seal+ a tube ?r\gh ano!r tube4 ,jo9ts1 gr\nd1 #ea ,jo9+ rod & tube1 #de tub+ end to end3 fir/ me?od1 #af second me?od1 #bj ,jo9+ tubes ( diff]5t diamet]s1 #be a new tube to a /opcock1 #dh ,kjeldahl trap1 #da ,lead glass1 #a ,lump ( glass1 remov$1 #ah1 #ai1 #bj1 #ba1 #bd1 #bf1 #cj1 #ch ,plat9um wires1 seal$ into glass1 #a1 #eb ,position = glass-work+1 #e ,pressure1 tubes = heat+ "u1 #ee ,quality ( glass1 #a ,rod1 glass1 work+1 #dd ,rotation ( ! tube1 #ac1 #ai ,r\nd$ end ( tube1 #ce1 #ch ,rubb] tube us$ = bl[+1 #bb ,seal+ a tube ?r\gh ano!r tube1 #ce1 #ci ,seal+ vacuum tubes1 #ee ,%r9k+ glass1 #ah1 #ai1 #bb1 #bf1 #ca ,side tube1 bl[+1 #bb1 #be ,soda glass1 #a ,s(t glass1 #a ,spirals1 mak+1 #ej ,/opcocks1 m5d+1 #de ,suction pump1 #ci1 #db ,sulphur dioxide tube1 #bh ,tail ( glass1 draw+ out1 #i1 #ed remov$1 #cj1 #ce ,tubes1 clos$1 = heat+ "u pressure1 #ee ,tee tube1 #bb on capill>y tub+1 #dc small side tube on a l>ge tube1 #bd ,vacuum tubes1 seal+1 #ee ,work+ temp]ature ( glass1 #a1 #ac1 #ai1 #bg ---------------------------------------- ------------------------------ ,transcrib]'s note3- ,words 9 italics are indicat$ by ! use ( und]scores & words 9 bold by ! use ( equals signs z %[n4 ---------------------------------------- ------------------------------