,libr>ies47 ,a ,,h&book ,,( ,,laboratory ,,glass-,,bl[+ ,to my ,fri5ds ,eric ,reid & ,sidney ,wilk9son ,a ,h&book ( ,laboratory ,glass-,bl[+ ,,by ,,b]n>d ,d4 ,,bolas ,,) ,,num]\s ,,diagrams ,,9 ,,! ,,text ,,by ,,naomi ,,bolas ,illu/ration ,,london ,,george ,,r\tl$ge ,,sons1 ,,ltd ,,new ,,york3 ,e4 ,p4 ,,dutton ,,co4 #aiba ,,cont5ts ,,*ap4 ,,page ,i4 ,introduction & ,prelim9>y ,rem>ks--,g5]al ,pr9ciples to be obs]v$ 9 ,glass ,work+--,*oice ( ,app>atus--,tools & ,appliances--,glass #a ,,ii4 ,easy ,examples ( ,laboratory ,glass-,bl[+--,cutt+ & ,seal+ ,tubes1 ,tubes = ,high ,temp]ature ,exp]im5ts--,!rmomet]-,bulbs1 ,bulbs ( ,special ,glass1 ,pipettes1 ,absorption-,bulbs or ,wa%+ ,bulbs--,jo9+ ,tubes1 ,bran*es1 ,exhau/ion-,bran*es1 ,bran*es ( ,dissimil> ,glass1 ,bl[+ ,bulbs1 ,a ,?i/le ,funnel1 ,crack+ & ,break+ ,glass1 ,lead+ & ,direction ( ,cracks--,use ( ,glass ,rod or ,/rips ( ,w9d[-,glass1 ,jo9+ ,rod1 ,feet & ,supports--,gripp+ ,devices = use 9 ,corrosive ,solutions--,! ,build+ up ( ,special ,=ms f ,solid ,glass #aj ,,iii4 ,int]nal ,seals1 ,air-,traps1 ,spray ,arre/]s1 ,filt]-,pumps--,sprays1 ,cond5s]s2 pla91 d\ble surface1 & sph]ical--,soxhlet ,tubes & ,fat ,extraction ,app>atus--,vacuum ,tubes1 ,electrode ,"w1 ,enclos$ ,!rmomet]s1 ,al>m ,!rmomet]s 444 ,record+ ,!rmomet]s1 ,sp9n+ ,glass #cb ,,iv4 ,glass1 its ,composition & ,*>act]i/ics--,anneal+--,drill+1 ,gr9d+1 & ,%ap+ ,glass by me?ods o!r ?an ,fusion--,/opcocks--,m>k+ ,glass--,calibration & ,graduation ( ,app>atus--,!rmomet]s--,exhau/ion ( ,app>atus--,jo9+ ,glass & ,metal--,silv]+ ,glass #ee ,v4 ,extemporis$ ,glass-,bl[+ ,app>atus--,! use ( ,oil or o!r ,fuels--,mak+ ,small ,rods & ,tubes f ,glass ,scraps--,! ,exam9ation ( ,manufactur$ ,app>atus ) a view to ,discov]+ ! ,me?ods us$ 9 ,manufacture--,summ>y ( ,conditions necess>y = ,successful ,glass-,bl[+ #hj ,index #aje ,,preface ,to cov] ! :ole field ( glass-bl[+ 9 a small h&book w\ld be impossible4 ,to attempt ev5 a complete outl9e ( ! me?ods us$ 9 mak+ comm]cial app>atus w\ld involve m ?an c\ld be und]tak5 )\t omitt+ ! ess5tial details ( manipulation t a novice ne$s4 ,i h1 !re=e1 conf9$ myself z f> z possible to su* "w z w f9d practical application 9 ! laboratory & w1 ,i hope1 prove ( value to ^? ^: int]e/s lie !re94 ,! me?od ( treatm5t & some:at disjo9t$ /yle ( writ+ h be5 *os5 solely ) ! view to economy ( space )\t ! undue sacrifice ( cle>ness4 ,,b]n>d ,d4 ,,bolas4 ,h&book ( ,laboratory ,glass-,bl[+ ,,*apt] ,i ,introduction & ,prelim9>y ,rem>ks--,g5]al ,pr9ciples to be obs]v$ 9 ,glass ,work+--,*oice ( ,app>atus--,tools & ,appliances--,glass4 ,glass-bl[+ is nei!r v easy nor v difficult2 !re are op]ations s easy t ! y\nge/ laboratory boy %\ld be able to repeat !m successfully aft] once hav+ be5 %[n ! way1 !re are op]ations s difficult t ye>s are ne$$ to tra9 eye & h& & judgm5t to c>ry !m out2 b ! great] numb] ( sci5tific ne$s lie betwe5 ^! two extremes4 ,yet a surpris+ly l>ge numb] ( sci5tific work]s fail ev5 to jo9 a glass tube or make a ,t piece t w n crack spontane\sly1 & ! fault is r "o ( und]/&+ ?an ( lack ( ability to c>ry out ! necess>y manipulation4 ,9 foll[+ ! s*eme ( in/ruction adopt$ 9 ?is h&book1 x w be well = ! /ud5t to pay p>ticul> att5tion to ! reason giv5 = ea* detail ( ! desirable proc$ure1 &1 z f> z may be1 to memorise x4 ,once hav+ ma/]$ ! und]ly+ reason1 he c evolve s*emes ( manipulation to suit 8 own p>ticul> ne$s1 al?\gh1 z a rule1 ^? giv5 9 ! foll[+ pages w be f\nd to embody ! result ( _m ye>s' exp]i5ce4 ,!re is a wide *oice ( app>atus1 f a simple m\?-bl[pipe & a c&le flame to a p[]-driv5 bl[] & a multiple-jet heat+ device4 ,all are useful1 & all h _! special applications1 b1 = ! pres5t1 we w consid] ! ord9>y types ( bell[s & bl[pipes1 su* z "o usually f9ds 9 a *emical or physical laboratory4 ,! usual1 or ,h]epa?1 type ( gas bl[pipe consi/s ( an out] tube ?r\gh :i* coal gas c be pass$ & an inn] tube ?r\gh :i* a /ream ( air may be bl[n4 ,su* a bl[pipe is %[n 9 section by ,fig4 #a4 ,x is desirable to h ! ?ree c5tr+ screws z %[n1 9 ord] to adju/ ! position ( ! air jet & obta9 a well-%ap$ flame1 b ^! screws are sometimes omitt$4 ,fig4 #a1 a & b %[ ! effects ( defective c5tr+ ( ! air jet1 c %[s ! effect ( dirt or r\ghness 9 ! inside ( ! air jet1 d %[s a satisfactory flame4 ,illu/ration3 ,fig #a ,= _m purposes1 x is an advantage to h :at is sometimes kn[n z a quick-*ange bl[pipe2 t is "o 9 :i* jets ( v>y+ size may be br\ght into position )\t /opp+ ! "w = m ?an a fraction ( a second4 ,su* a device is made by ,messrs4 ,let*]1 & is %[n by e1 & 9 section by f ,fig4 #a4 ,x is only necess>y to rotate ! desir$ jet into position 9 ord] to connect x ) bo? gas & air supplies4 ,a small bye-pass ignites ! gas1 & adju/m5t ( gas & air may be made by a p>tial rotation ( ! cyl9d] :i* c>ries ! jets4 ,= specially heavy "w1 :]e x is ne$$ to heat a l>ge mass ( glass1 a multiple bl[pipe jet ( ! patt]n inv5t$ by my fa!r1 ,?omas ,bolas1 z ! result ( a sugge/ion d]iv$ f a /udy ( ! jet us$ 9 ,griff9's gas furnace1 is ( consid]able value4 ,?is jet consi/s ( a block ( metal 9 :i* are drill$ sev5 holes1 "o be+ c5tral & ! o!r six arrang$ 9 a close circle ar\nd ! c5tral hole4 ,to ea* ( ^! holes is a communication way lead+ to ! gas supply1 & an air jet is arrang$ c5trally 9 ea*4 ,ea* hole has also an ext5sion tube fitt$ into x1 ! :ole effect be+ t ( sev5 bl[pipes4 ,9 ord] to provide a f9al adju/m5t = ! flame1 a p]=at$ plate hav+ sev5 holes :i* correspond 9 size & position to ! out] tubes is arrang$ to slide on p>allel guides 9 front ( ^! out] tubes4 ,illu/ration3 ,fig4 #b ,! next piece ( app>atus = consid]ation is ! bell[s1 ( :i* !re are ?ree or m types on ! m>ket1 al?\gh all consi/ ( two ess5tial p>ts1 ! bl[] or bell[s prop] & ! w9d *amb] or res]voir4 ,two patt]ns are %[n 9 ,fig4 #b2 a1 is ! =m :i* is commonly us$ by jewell]s & metal work]s to supply ! air bla/ necess>y = heat+ small furnaces4 ,su* a bell[s may be obta9$ at almo/ any jewell]s' supply deal] 9 ,cl]k5well1 b x n infrequ5tly happ5s t ! spr+ 9 ! w9d *amb] is too /rong = glass-bl[+1 & h5ce ! air supply t5ds to v>y 9 pressure4 ,?is c be improv$ by fitt+ a weak] spr+1 b an easi] way & "o t usually gives fairly satisfactory results1 is to place an ord9>y screw-clip on ! rubb] tube lead+ f ! bell[s to ! bl[pipe1 & to tight5 ?is until an ev5 bla/ is obta9$4 ,ano!r =m ( bell[s1 made by ,messrs4 ,flet*] & ,co41 & common 9 mo/ laboratories1 is %[n by b2 ! w9d *amb] consi/s ( a disc ( india-rubb] clamp$ "u a circul> frame or ti$ on to a circul> rim4 ,?is =m is %[n by ,fig4 #b1 b4 ,! ?ird =m1 & "o :i* my own exp]i5ce has caus$ me to pref] to any o!r1 is cyl9drical1 & /&s inside ! p$e/al ( ! bl[pipe-table4 ,a bl[pipe-table ( ?is description is made by ,enf] ( ,p>is4 ,!re is no ne$1 h[ev]1 to pur*ase an exp5sive table = laboratory use4 ,all ! "w describ$ 9 ?is book c q well be done ) a simple foot bell[s & a quick-*ange bl[pipe4 ,ne>ly all ( x c be done ) a s+le jet bl[pipe1 su* z t describ$ fir/1 or ev5 ) ! /ill simpl] app>atus m5tion$ on page #hd1 b ,i d n advise ! beg9n] to practise ) q s simple a =m at fir/1 & = t reason h po/pon$ a description ( x until ! la/ *apt]4 ,glass-bl[]s' tools & appliances are _m & v>i\s1 q a numb] ( !m are bett] reject$ ?an us$1 b !re are a few ess5tials4 ,^! are1--file1 glass-knife1 small turn-p91 l>ge turn-p91 c>bon cones1 c>bon plate1 rubb] tube ( small diamet]1 v>i\s sizes ( corks1 & an asbe/os heat reflector4 ,= ord9>y "w1 an anneal+ ov5 is n necess>y1 b "o is describ$ on page #fj 9 connection ) ! special cases :]e anneal+ is desirable4 ,fig4 #c illu/rates ! tools & appliances4 a is an end view ( ! desirable =m ( file1 & %[s ! be/ me?od ( gr9d+ ! edges 9 ord] to obta9 a highly satisfactory tool4 b is a glass knife1 %[n bo? 9 p]spective & end view1 x is made ( glass-h>d /eel & %\ld be %>p5$ on a r\gh /one1 su* z a scy!-/one1 9 ord] to give a slightly irregul> edge4 c is a small turn-p9 :i* may be made by flatt5+ & fil+ ! end ( a six-in* nail4 d is ! l>ge turn-p9 & consi/s ( a poli%$ iron spike1 ab\t five in*es long & a qu>t] ( an in* diamet] at its l>ge/ "p4 ,?is %\ld be m\nt$ 9 a wood5 h&le4 e & f are c>bon cones4 ,a ?9 rubb] tube is also useful2 x may be atta*$ to ! "w & s]ve z a bl[+ tube1 ?us obviat+ ! necessity ( mov+ ! "w to ! m\? :5 int]nal air pressure is to be appli$4 ,9 ord] to avoid undue repetition1 ! uses ( ^! tools & appliances w be describ$ z !y occur4 ,illu/ration3 ,fig4 #c ,glass1 z usually suppli$ by *emical app>atus deal]s is ( ! composition kn[n z soda-glass4 ,!y also supply h>d or combu/ion glass1 b ?is is only us$ = special purposes1 z x is too infusible = conv5i5t work+ 9 ! ord9>y bl[pipe flame4 ,soda-glass consi/s prim>ily ( silicate ( sodium ) small] quantities ( silicate ( alum9um & potassium4 ,its exact composition v>ies4 ,x is n black5$1 z lead glass is1 by exposure to ! r$uc+ gases :i* are pres5t 9 ! blue cone ( a bl[pipe flame1 & h5ce is easi] = a beg9n] to "w )\t produc+ discol\ration4 ,fur!r notes on glasses w be f\nd on page #ee1 b = ord9>y purposes soda-glass w probably be us$4 ,,*apt] ,,ii ,easy ,examples ( ,laboratory ,glass-,bl[+--,cutt+ & ,seal+ ,tubes = ,v>i\s ,purposes2 ,te/-,tubes1 ,pressure-,tubes1 ,tubes = ,high ,temp]ature ,exp]im5ts--,!rmomet]-,bulbs1 ,bulbs ( ,special ,glass1 ,pipettes1 ,absorption-,bulbs or ,wa%+-,bulbs--,jo9+ ,tubes2 ,bran*es1 ,exhau/ion-,bran*es1 ,bran*es ( ,dissimil> ,glass--,bl[+ ,bulbs2 ,a ,?i/le ,funnel2 ,crack+ & ,break+ ,glass2 ,lead+ & ,direction ( ,cracks--,use ( ,glass ,rod or ,/rips ( ,w9d[-,glass2 ,jo9+ ,rod1 ,feet & ,supports--,gripp+ ,devices = use 9 ,corrosive ,solutions--,! ,build+ ,up ( ,special ,=ms f ,solid ,glass4 ,p]haps ! mo/ common ne$ ( ! glass-bl[] ^: "w is connect$ ) t ( ! laboratory is = a seal$ tube2 & ! seal+ ( a tube is an excell5t prelim9>y ex]cise 9 glass-bl[+4 ,we w assume t ! /ud5t has adju/$ ! bl[pipe to give a flame simil> to t %[n 9 d1 ,fig4 #a1 & t he has le>n$ to ma9ta9 a /eady bla/ ( air ) ! bell[s2 fur!r1 we w assume t ! tube he wi%es to seal is ( mod]ate size1 say n m ?an half an in* 9 diamet] & ) walls ( f "o-t5? to "o-fif? ( an in* ?ick4 ,illu/ration3 ,fig4 #d ,a conv5i5t l5g? ( tube = ! fir/ trial is ab\t "o foot2 ?is %\ld be cut (f f ! long] piece1 9 :i* x is usually suppli$1 z foll[s3--lay ! tube on a flat surface & make a deep cut ) ! edge ( a file4 ,d n saw ! file to & fro ov] ! glass4 ,if ! file edge has be5 gr\nd z %[n 9 a1 ,fig4 #c1 su* a proc$ure w be q unnecess>y & only involve undue we>2 "o movem5t ) suffici5t pressure to make ! file bite w give a deep cut4 ,n[ rotate ! tube ?r\gh ab\t "o-eigh? ( a turn & make ano!r cut 9 cont9uation ( ! fir/4 ,take ! tube 9 ! h&s1 z %[n 9 a1 ,fig4 #d1 & apply pressure ) ! ?umbs1 at ! same "t /ra9+ at ! ends4 ,! tube %\ld break easily4 ,if x does n1 d n /ra9 too h>d1 z x may %att] & cause s]i\s injuries to ! h&s1 b repeat ! op]ation ) ! file & s deep5 ! orig9al cuts4 ,9 hold+ a tube = break+1 x is important to place ! h&s z %[n 9 sket*1 z ?is me?od is lea/ likely to cause %att]+ & also m9imises ! risk ( injury ev5 if ! tube %\ld %att]4 ,to cut a l>ge tube1 or "o hav+ v ?ick walls1 x is bett] to avoid /ra9+ altoge!r & to break by apply+ a small bead ( int5sely heat$ glass to ! file cut4 ,if ! walls are v ?91 a glass-bl[]'s knife %\ld be us$ in/ead ( a file4 ,! tube & glass-bl[]'s knife %\ld be held 9 ! h&1 & ! tube rotat$ aga9/ ! edge ( ! knife2 ?is w n produce a deep cut1 b is less likely to break ! tube4 ,a bead ( hot glass %\ld be us$ to complete ! "w4 ,! next op]ation is to heat ! glass tube 9 ! middle2 ?is mu/ be done gradually & ev5ly2 t is to say ! tube mu/ be rotat$ dur+ heat+ & held "s consid]able di/ance 9 front ( ! flame at fir/2 o!rwise ! out] surface ( ! glass w exp& be=e ! int]ior is affect$ & ! tube w break4 ,f two to five m9utes1 heat+ at a di/ance ( ab\t eight in*es 9 front ( ! flame w be f\nd suffici5t 9 mo/ cases1 & ano!r m9ute %\ld be tak5 9 br++ ! tube into ! flame4 ,gradual heat+ is important1 b ev5 heat+ is /ill m important & ?is c only be obta9$ by uni=m & /eady rotation4 ,until ! /ud5t c rotate a tube /eadily )\t ?9k+ ab\t x1 real progress 9 glass-bl[+ is impossible4 ,:5 ! tube is 9 ! flame x mu/ be held j 9 front ( ! blue cone & rotat$ until ! glass is s(t en\gh to p]mit ! ends to be drawn ap>t4 ,cont9ue to sep>ate ! ends &1 at ! same "t1 move ! tube v slightly along its own axis1 s t ! flame t5ds to play a little m on ! ?ick] "p ?an on ! drawn-out portion4 ,if ?is is done c>efully1 ! drawn-out portion c be sep>at$ (f1 leav+ only a slight bleb on ! portion x is desir$ to seal4 ,?is is illu/rat$ by b1 ,fig4 #d4 ,to conv]t ! seal at b1 ,fig4 #d41 into ! ord9>y =m ( te/-tube seal1 x is only necess>y to heat ! bleb a little m /rongly1 bl[ g5tly into ! tube until ! ?ick portion is slightly exp&$1 re-heat ! :ole ( ! r\nd$ end until x is beg9n+ to collapse1 & give a f9al %ap+ by c>eful bl[+ aft] x has comm5c$ to cool4 ,9 ea* case ! glass mu/ be remov$ f ! flame be=e bl[+4 ,! f9i%$ seal is %[n by c1 ,fig4 #d4 ,if desir$1 ! op5 end may n[ be f9i%$ by heat+ & rotat+ ! s(t glass aga9/ ! l>ge turn-p91 z illu/rat$ 9 d1 b ! turn-p9 mu/ n be all[$ to become too hot1 z if ?is happ5s x w /ick to ! glass4 ,aft] turn+ out ! end1 ! lip ( glass mu/ be heat$ to r$ness & all[$ to cool )\t com+ 9 contact ) any?+2 o!rwise x w be 9 a condition ( /ra9 & liable to crack spontane\sly4 ,! f9i%$ te/-tube is %[n by e4 ,:5 x is necess>y to seal a sub/ance inside a glass tube1 ! bottom ( ! tube is fir/ clos$1 z expla9$ above1 & all[$ to cool2 ! sub/ance1 if a solid1 is n[ introduc$1 b %\ld n come to )9 less ?an two in*es ( ! po9t :]e ! second seal is to be made4 ,if ! sub/ance is a liquid x c m conv5i5tly be introduc$ at a lat] /age4 ,n[ br+ ! tube into ! bl[pipe flame gradually1 & rotate x1 :ile heat+1 at ! place :]e x is to be clos$4 ,all[ ! glass to s(t5 & comm5ce to run toge!r until ! diamet] ( ! tube is r$uc$ to ab\t half its orig9al size4 ,remove f ! flame & draw ! ends ap>t1 ?is %\ld give a long1 ?ick ext5sion z %[n by f1 ,fig4 #d4 ,if any liquid is to be introduc$1 x may n[ be done by ins]t+ a ?9 rubb] or o!r tube ?r\gh ! op5+ & runn+ ! liquid 94 ,a glass tube %\ld be us$ ) caution = introduc+ ! liquid1 z any h>d sub/ance w t5d to scrat* ! inside ( ! glass & cause crack+4 ,! f9al closure is made by melt+ ! drawn-out ext5sion 9 ! bl[pipe flame2 ! f9i%$ seal be+ %[n by g1 ,fig4 #d4 ,if ! seal$ tube has to /& int]nal pressure1 x is desirable to all[ ! glass to ?ick5 some:at m be=e draw+ out1 & ! bottom seal %\ld also be made ?ick]4 ,= su* a tube1 & especially :5 x has to /& heat+1 z 9 a ,c>ius det]m9ation ( *lor9e1 ea* seal %\ld be cool$ v sl[ly by rotat+ x 9 a gas flame until ! surface is cov]$ ) a ?ick lay] ( soot1 & x %\ld !n be plac$ aside 9 a position :]e ! hot glass w n come 9 contact ) any?+1 & :]e x w be scre5$ f all draughts4 ,jo9+ ,tube4--,we w n[ consid] ! v>i\s =ms ( jo9 9 glass tub+ :i* are met ) 9 ! laboratory4 ,fir/1 z be+ easie/1 we w deal ) ! end-to-end jo9+ ( two tubes ( simil> glass4 a1 b1 & c1 ,fig4 #e1 illu/rate ?is4 ,"o end ( "o ( ! tubes %\ld be clos$1 a lip %\ld be turn$ out on ea* ( ! ends to be jo9$1 & bo? lips heat$ simultane\sly until ! glass is ?or\ghly s(t4 ,n[ br+ ! lips toge!r g5tly1 until !y are 9 contact at all po9ts & !re are no places at :i* air c escape2 remove f ! flame1 & bl[ sl[ly & v cauti\sly until ! jo9t is exp&$ z %[n 9 b1 ,fig4 #e4 ,reheat 9 ! flame until ! glass has run d[n to r less ?an ! orig9al diamet] ( ! tube1 & give a f9al %ap+ by re-bl[+4 ,! *ief factors ( success 9 mak+ su* a jo9 are1 ?or\gh heat+ ( ! glass be=e br++ ! two tubes toge!r1 & avoidance ( h>d or sudd5 bl[+ :5 exp&+ ! jo9t4 ,! f9i%$ "w is %[n by c1 ,fig4 #e4 ,illu/ration3 ,fig4 #e ,to jo9 a small glass tube to ! end ( a l>ge "o1 ! l>ge tube %\ld fir/ be seal$1 a small spot on ! extreme end ( ! seal heat$1 & air pressure us$ to exp& ! heat$ spot z %[n 9 d4 ,?is exp&$ spot is !n re-heat$ & bl[n out until x bur/s z %[n 9 e1 ! ?9 fragm5ts ( glass are remov$ & ! end ( ! small tube turn$ out z %[n 9 f4 ,aft] ?is ! proc$ure is simil> to t us$ 9 jo9t+ two tubes ( equal size4 ,:5 ^! two =ms ( jo9t h be5 ma/]$1 a ,t piece w pres5t b little difficulty4 ,x is made 9 ?ree /ages z %[n 9 ,fig4 #e1 & ! proc$ure is simil> to t us$ 9 jo9+ a l>ge & small tube4 ,c>e %\ld be tak5 to avoid s(t5+ ! top ( ! ,t too mu*1 or ! glass w b5d & di/ort ! f9i%$ "w2 al?\gh a slight b5d c be rectifi$ by re-heat+ & b5d+ back4 ,local re-heat+ is (t5 useful 9 giv+ ! jo9t its f9al %ape4 ,an exhau/ion bran* is (t5 made by a totally diff]5t me?od4 ,?is me?od is %[n by g1 h1 & i1 ,fig4 #e2 g is ! tube on :i* ! bran* is to be made4 ,! end ( a rod ( simil> glass %\ld be heat$ until a mass ( ?or\ghly liquid glass has collect$1 z %[n1 & at ! same "t a spot %\ld be heat$ on t "p ( ! tube :]e x is desir$ to make ! bran*4 ,! mass ( hot glass on ! rod is n[ br\ght 9 contact ) ! heat$ spot on ! tube & exp&$ by bl[+ z %[n by h4 ,! air pressure 9 ! tube is /ill ma9ta9$ :ile ! rod is drawn away z %[n by i4 ,?is w give a holl[ bran* :i* may be cut (f at any desir$ po9t1 & is !n ready = connection to ! vacuum pump4 ,if ! rod us$ is ( a dissimil> glass1 ! bran* %\ld be bl[n mu* ?9n]4 ,su* a bran* w (t5 s]ve z a useful basis = jo9+ two tubes ( diff]5t composition1 z ! ord9>y type ( bran* is m liable to crack :5 made ) two glasses hav+ diff]5t coeffici5ts ( expansion4 ,bl[+ ,bulbs4--,a bulb may be bl[n on a clos$ tube su* z t %[n by c1 ,fig4 #e1 by rotat+ x 9 ! bl[pipe flame until ! end is s(t5$1 remov+ x f ! flame & bl[+ cauti\sly4 ,x is desirable to cont9ue ! rotation dur+ bl[+4 ,9 ! case ( a v small tube1 x is suffici5t to melt ! end )\t previ\s seal+1 rotate x 9 ! flame until en\gh glass has collect$1 remove f ! flame & bl[ :ile keep+ ! tube 9 rotation4 ,!rmomet] ,bulbs4--,if ! !rmomet] is to be fill$ ) m]cury1 x is desirable to use a rubb] bulb = bl[+1 z moi/ure is liable to cond5se inside ! tube :5 ! m\? is us$1 & ?is moi/ure w cause ! m]cury ?read to break4 ,9 any case1 a slight pressure %\ld be ma9ta9$ inside ! !rmomet] tube :ile x is 9 ! flame2 o!rwise ! f9e capill>y tube w close & x w be v difficult to exp& ! heat$ glass into a bulb4 ,l>ge ,bulbs4--,:5 a l>ge bulb is ne$$ on a small or m$ium siz$ tube1 x is (t5 necess>y to provide m glass ?an w\ld be obta9$ if ! bulb 7 bl[n 9 ! ord9>y way4 ,"o me?od is to exp& ! tube 9 successive /ages along its axis1 z %[n by a1 ,fig4 #f4 ,^! exp&$ portions are !n re-heat$1 s t !y run toge!r into "o holl[ mass f :i* ! bulb is bl[n2 b & c1 illu/rate ?is4 ,ano!r me?od1 & "o :i* is useful = v l>ge bulbs1 is to fuse on a l5g? ( l>ge1 ?ick-wall$1 tub+4 ,! heat reflector1 g1 ,fig4 #c1 %\ld be us$1 if necess>y1 :5 mak+ l>ge bulbs4 ,x consi/s ( a %eet ( asbe/os m\nt$ 9 a foot1 & is us$ by be+ plac$ close to ! mass ( glass on ! side away f ! bl[pipe flame :ile ! glass is be+ heat$4 ,illu/ration3 ,fig4 #f ,bulbs ( ,dissimil> ,glass4--,^! may be made by ! second me?od giv5 "u ,l>ge ,bulbs1 b ! jo9t %\ld be bl[n z ?9 z possible4 ,fur!r in/ructions 9 ! use ( unlike glasses are giv5 on page #id4 ,a ,bulb 9 ! ,middle ( a ,tube4--,unless ! bulb is to be q small1 x w be necess>y to jo9 9 a piece ( ?ick glass tub+1 or to draw ! ?9 tube out f a l>g] piece1 ?us leav+ a ?ick mass 9 ! middle z %[n by d1 ,fig4 #f4 ,?is mass ( glass %\ld n[ be rotat$ 9 ! bl[pipe flame until x is q s(t & on ! po9t ( runn+ toge!r4 ,consid]able practice w be necess>y be=e ! two ends ( ! tube c be rotat$ at ! same spe$ & )\t wobbl+1 b ?is p[] mu/ be acquir$4 ,:5 ! glass is ?or\ghly hot1 remove f ! flame1 hold 9 a horizontal position1 & exp& by bl[+4 ,x is ess5tial to cont9ue ! rotation :ile ?is is done4 ,%\ld "o "p ( ! bulb t5d to exp& m ?an ! o!r1 turn ! exp&$ "p to ! bottom1 pause = ab\t a second1 bo? 9 rotat+ & bl[+1 9 ord] t ! l[] portion may be cool$ by asc5d+ air-curr5ts2 !n cont9ue bl[+ & turn+ z be=e4 ,absorption ,bulbs or ,wa%+ ,bulbs4--,^! are made by an elaboration ( ! processes giv5 9 ! la/ p>agraph1 g1 h1 & i1 ,fig4 #f1 illu/rate ?is4 ,a ,?i/le ,funnel4--,?is is made by bl[+ a fairly ?ick-wall$ bulb on a glass tube1 bur/+ a hole by heat+ & bl[+1 & enl>g+ ! bur/-out "p by heat+ & rotat+ aga9/ a turn-p94 ,b5d+ ,glass ,tube4--,small tub+ may be b5t 9 a flat flame gas burn] & (f]s no special difficulty4 ,l>ge or ?9-wall$ tub+ %\ld be heat$ 9 ! bl[pipe flame & a slight b5d made2 ano!r zone ( ! tube1 j t\*+ ! fir/ b5d1 %\ld n[ be heat$ & ano!r slight b5d made4 ,9 ?is way x is possible to avoid flatt5+ & a b5d hav+ any requir$ angle c gradually be produc$4 ,a f9al %ap+ ( ! b5d may be made by heat+ 9 a l>ge bl[pipe flame & exp&+ slightly by air pressure4 ,glass ,spirals4--,if a tube is heat$ by means ( a long1 flat-flame burn]1 ! s(t5$ tube may be w\nd on to an iron m&rel :i* has previ\sly be5 cov]$ ) asbe/os4 ,! m&rel %\ld be made slightly conical 9 ord] to facilitate )drawal4 ,x is desirable to heat ! surface ( ! asbe/os almo/ to r$ness by means ( a second burn]1 & ?us avoid undue *ill+ ( ! glass & ! consequ5t production ( int]nal /ra94 ,illu/ration3 ,fig4 #g ,a ,!rmo-,regulator = ,gas4--,fig4 #g1 a-e1 %[s an easily con/ruct$ !rmo-regulator4 ,! m]cury res]voir1 a1 & ! upp] "p1 b1 are made by jo9+ two l>g] pieces ( tub+ on to ! capill>y4 ,! gas inlet passes ?r\gh a rubb] /opp]1 9 ord] to all[ ( adju/m5t = dep? ( ins]tion1 & ! bye-pass bran*es1 d & e1 are connect$ by a piece ( rubb] tub+ :i* c be compress$ by means ( a screw clip1 ?us provid+ a means ( regulat+ ! bye-pass4 ,use ( ,glass ,rod4--,ap>t f its mo/ common laboratory use = /irr+2 glass rod may be us$ 9 build+ up su* articles z insulat+ feet = electrical app>atus or acid-resi/+ cages = *emical purposes4 ,su* a cage is %[n by f1 g & h1 ,fig4 #g4 ,fur!r1 by an elaboration ( ! me?od ( mak+ an exhau/ion bran*1 giv5 on page #ah1 bl[n articles may also be con/ruct$ f rod4 ,note ! add$ p>ts ( e1 ,fig4 #i4 ,a ,simple ,foot4--,! =m ( foot %[n by ,fig4 #g1 k1 is easy to make & has _m uses4 ,fir/ jo9 a glass rod to a l5g? ( glass tub+ z %[n 7! jo9t %\ld be exp&$ slightly by bl[+71 cut (f ! tube & heat ! piece rema9+ on ! rod until x c be turn$ out z %[n by i4 ,?is %\ld be done ) ! l>ge turn-p91 & c>e %\ld be tak5 n to heat ! support+ rod too /rongly1 o!rwise ! piece ( tube w become b5t & di/ort$2 x is bett] to comm5ce by heat+ ! edge ( ! piece ( tube & turn out a lip1 !n ext5d ! heat+ by degrees & turn out m & m until ! foot looks l t %[n by i4 ,we n[ ne$ to make ?ree projections ( glass rod4 ,^! are produc$ z foll[s3--,heat ! end ( ! glass rod until a ?or\ghly melt$ mass ( glass has accumulat$ 7! rod mu/ be rotat$ :ile ?is is be+ done1 o!rwise ! glass w drop (f72 :5 suffici5t melt$ glass has be5 obta9$1 ! edge ( ! turn$-out foot %\ld be heat$ to dull r$ness ov] ab\t "o-?ird ( its circumf]5ce1 & ! melt$ glass on ! rod %\ld be drawn along ! heat$ portion until bo? are s completely 9 contact z to =m "o mass ( semi-fluid glass4 ,! rod %\ld n[ be drawn away sl[ly1 &1 f9ally1 sep>at$ by melt+ (f1 ?us produc+ a flat projection4 ,a repetition ( ! process w give ! o!r two projections1 & ! f9i%$ foot may be adju/$ to /& upright by heat+ ! projections slightly & /&+ x on ! c>bon plate m5tion$ on page #g4 ,aft] ! foot is adju/$ x %\ld be anneal$ slightly by heat+ to j bel[ ! s(t5+ po9t ( ! glass & !n rotat+ 9 a smoky gas flame until x is cov]$ ) a deposit ( c>bon1 aft] :i* x %\ld be all[$ to cool 9 a place free f draughts & :]e ! hot glass w n come 9 contact ) any?+4 ,! f9i%$ foot is %[n by k1 ,fig4 #g4 ,build+ up f ,glass ,rod4--,a glass skeleton-"w c be con/ruct$ f rod )\t mu* difficulty1 & is sometimes useful z a conta9] = a sub/ance :i* has to be treat$ ) acid1 or = simil> purposes4 ,! me?od is almo/ suffici5tly expla9$ by ! illu/ration 9 ,fig4 #g2 f %[s ! initial /age1 g ! me?od ( con/ruction ( ! net-"w1 & h ! f9i%$ conta9]4 ,x is conv5i5t to introduce ! sub/ance at ! /age indicat$ by g4 ,! important po9ts to obs]ve 9 mak+ ?is contrivance are t ! glass rod mu/ be kept hot by work+ :ile x is actually 9 ! flame1 & t ! skeleton mu/ be made z ?9 z possible ) ! avoidance ( heavy masses ( glass at any place4 ,if ^! details are neglect$ x w be almo/ c]ta9 to crack4 ,/irr]s4--,^! are usually made f glass rod1 & no special in/ructions are necess>y = _! con/ruction1 except t ! glass %\ld be 9 a ?or\ghly fus$ condition be=e mak+ any jo9s & ! f9i%$ jo9 %\ld be anneal$ slightly by cov]+ ) a deposit ( soot1 z expla9$ on page #af4 ,! flat ends %[n 9 a1 ,fig4 #h1 are made by squeez+ ! s(t glass rod betwe5 two pieces ( c>bon1 & %\ld be re-heat$ to dull r$ness aft] %ap+4 ,fig4 #h also %[s v>i\s =ms ( /irr]4 ,9 ord] to c>ry out /irr+ op]ations 9 ! pres5ce ( a gas or mixture ( gases o!r ?an air1 "s =m ( gl& or seal may be necess>y :]e ! /irr] passes ?r\gh ! be>+ 9 :i* x runs4 ,a flask to :i* is fitt$ a /irr] & gas seal is %[n 9 section by b1 ,fig4 #h4 ,! liquid us$ 9 ?is seal may be m]cury1 petroleum1 or any o!r t ! exp]im5tal conditions indicate4 ,illu/ration3 ,fig4 #h ,if ! be>+ = a /irr] is made ( glass tube1 x is desirable to lubricate r freely2 o!rwise heat w be produc$ by ! friction ( ! /irr] & ! tube w probably crack4 ,su* lubrication may be suppli$ by turn+ out ! top ( ! be>+ tube & fill+ ! turn$-out portion ) petroleum jelly mix$ ) a small quantity ( f9ely gr\nd or1 bett]1 colloidal graphite1 & ! be>+ %\ld also be lubricat$ ) ! same composition4 ,c>e %\ld be tak5 n to employ s s(t a lubricant or s l>ge an excess z to cause x to run d[n ! /irr] into ! liquid :i* is be+ /irr$4 ,lead+ a ,crack4--,x sometimes happ5s t a l>ge bulb or specially ?9-wall$ tube has to be divid$4 ,9 su* a case x is sc>cely practicable to use ! me?od recomm5d$ = small tubes on page #ab1 b x is q easy to lead a crack 9 any desir$ direction4 ,a conv5i5t />t+ po9t is a file cut2 ?is is t\*$ ) hot glass until a crack is initiat$4 ,a small flame or a bead ( hot glass is n[ us$ to heat ! article at a po9t ab\t a qu>t] ( an in* f ! end ( ! crack & 9 :atev] direction x has to be l$4 ,! crack w n[ ext5d t[>ds ! s\rce ( heat1 :i* %\ld be mov$ f>!r away z ! crack advances4 ,9 ?is mann] a crack may be caus$ to take any desir$ pa? & c be l$ r\nd a l>ge bulb4 ,cutt+ ,glass ) ! ,diamond4--,slips ( w9d[-glass c be us$ 9 place ( glass rod = "s purposes1 & z cutt+ !m involves ! use ( ! glazi]s' diamond or a :eel-cutt]1 !y may well be m5tion$ "u ?is head+4 ,9 cutt+ a %eet ( glass ) ! diamond1 "o ne$s a flat surface on :i* to re/ ! glass1 & a rule aga9/ :i* to guide ! diamond4 ,! diamond %\ld be held 9 an almo/ v]tical position1 & drawn ov] ! surface ( ! glass ) slight pressure4 ,:ile ?is is be+ done ! angle ( ! diamond %\ld be *ang$ by br++ ! top ( ! h&le =w>d until ! s\nd *anges f "o ( scrat*+ to a cle> s++ note4 ,:5 ?is happ5s ! diamond is cutt+4 ,a few trials w tea* ! /ud5t ! correct angle = ! diamond ) :i* he works1 & ! glass1 if prop]ly cut1 w break easily4 ,if ! cut fails x is bett] to turn ! glass ov] & make a correspond+ cut on ! o!r side r ?an make any attempt to improve ! orig9al cut4 ,! diamond is seldom us$ = cutt+ small glass tubes4 ,! use ( ! :eel-cutt] calls = no special m5tion z x w cut at any angle1 al?\gh ! pressure requir$ is some:at great] ?an t ne$$ by mo/ diamonds4 ,,*apt] ,,iii ,int]nal ,seals1 ,air-,traps1 ,spray ,arre/]s1 ,filt]-,pumps--,sprays1 ,cond5s]s2 ,pla91 ,d\ble ,surface1 & ,sph]ical--,soxhlet ,tubes & ,fat ,extraction ,app>atus--,vacuum ,tubes1 ,electrode ,"w1 ,enclos$ ,!rmomet]s1 ,al>m ,!rmomet]s1 ,record+ ,!rmomet]s1 ,sp9n+ ,glass4 ,int]nal ,seals4--,x is conv5i5t to class ^? cases 9 :i* a glass tube passes ?r\gh ! wall ( ano!r tube or bulb "u ! head+ ( ,int]nal ,seals4 ,^! are met ) 9 b>omet]s1 spray arre/]s1 & filt] pumps1 9 cond5s]s & "s =ms ( vacuum tube4 ,! two pr9cipal me?ods ( mak+ su* seals w be consid]$ fir/ & _! special application aft]w>ds4 ,an ,air ,trap on a ,b>omet] ,tube4--,?is involves ! use ( ! fir/ me?od1 & is p]haps ! simple/ example t c be giv54 ,fig4 #i1 a1 a#a & a#b1 %[ ! /ages by :i* ?is =m ( int]nal seal is made4 ,= ! fir/ trials1 x is well to "w ) fairly ?ick-wall$ tub+1 :i* %\ld be cut into two pieces1 ea* be+ ab\t eight in*es long4 ,illu/ration3 ,fig4 #i ,fir/ seal ! end ( "o tube z describ$ on page #ac1 heat ! seal$ end & exp& to a ?ick wall$ bulb4 ,fuse ! end ( ! o!r tube1 atta* a piece ( glass rod to s]ve z a h&le1 & draw out2 cut (f ! drawn-out portion3 leav+ an end l a4 ,n[ heat a small spot at ! end ( ! bulb1 bl[1 bur/ out1 & remove ! ?9 fragm5ts ( glass4 ,heat a zone on ! o!r tube at ! po9t :]e ! drawn-out portion comm5ces & exp& z %[n by a#a4 ,! next /age is to jo9 ! tubes4 ,heat ! ragg$ edges ( ! bur/-out portion until !y are ?or\ghly r\nd$4 ,at ! same "t heat ! drawn-out tube to j bel[ s(t5+ po9t4 ,!n1 :ile ! r\nd$ edges ( ! bur/-out portion are /ill s(t1 ins]t ! o!r tube2 rotate ! jo9 9 ! bl[pipe flame until x is q s(t1 & exp& by bl[+4 ,if necess>y1 re-heat & exp& aga94 ,! f9i%$ seal1 :i* %\ld be slightly anneal$ by smok+ 9 a sooty flame1 is %[n by a#b4 ,a ,spray ,arre/]4--,?is is made by ! second me?od1 9 :i* ! piece ( tube :i* projects inside ! bulb is fus$ 9 position fir/ & ! out] tube is !n jo9$ on4 ,! v>i\s /ages ( mak+ are illu/rat$ by b1 b#a & b#b1 ,fig4 #i4 ,a bulb is bl[n betwe5 two tubes by ! me?od giv5 on page #bb1 ! l>g] tube is !n cut (f & ! small piece ( tube introduc$ into ! bulb aft] hav+ be5 %ap$ z %[n 9 by b1 ,fig4 #i4 ,! op5+ 9 ! bulb is seal$ z %[n by b#a4 ,! seal$ "p is n[ heat$ & ! bulb incl9$ d[nw>ds until ! inn] tube comes 9 contact ) ! seal & is fus$ 9 position4 ,?is op]ation requires "s practice 9 ord] to prev5t ! inn] tube ei!r fall+ ?r\gh ! s(t glass or becom+ unsymmetrical4 ,! end ( ! bulb1 :]e ! inn] tube comes 9 contact ) x1 is n[ p]=at$ by heat+ & bl[+1 ?us giv+ ! =m %[n by b#b1 & ! out] tube is jo9$ on4 ,! f9i%$ spray arre/] is %[n by b#c4 ,practice alone w give ! p[] to produce a symmetrical & /able piece ( "w4 ,two ,=ms ( ,filt] ,pump4--,t illu/rat$ by d1 ,fig4 #i1 is made by ! me?od expla9$ "u ,an ,air ,trap on a ,b>omet] ,tube4 ,t illu/rat$ by c is made by ! me?od expla9$ "u ,a ,spray ,arre/]4 ,no new manipulation is involv$1 & ! con/ruction %\ld be cle> f a /udy ( ! draw+s4 ,multiple & ,bran*$ ,int]nal ,seals4--,a full] consid]ation ( ^! w be f\nd on page #ci1 b "o g5]al pr9ciple may well be borne 9 m9d2 t1 z f> z is possible1 a tube hav+ bo? ends fa/5$ inside ano!r tube or bulb %\ld be curv$ or h a spiral or bulb at "s po9t 9 its l5g?1 o!rwise any expansion or contraction w put great /ra9 on ! jo9ts4 ,sprays4--,a spray :i* is easy to make1 easy to adju/1 & easy to clean aft] use is %[n by e1 ,fig4 #i4 ,! op5+ on ! top ( ! bulb is made by melt+ on a bead ( glass1 exp&+1 bur/+1 & fus+ ! ragg$ edges4 ,! two bran*es :i* =m ! spray produc+ junction are made by ! me?od us$ = an exhau/ion bran* & describ$ on page #ah4 ,a spray :i* c be introduc$ ?r\gh ! neck ( a bottle is %[n by h1 ,fig4 #i4 ,! v>i\s /ages 9 mak+ ?is are illu/rat$ by f1 & g4 ,if ! inn] tube is made by draw+ out f a l>g] piece ( glass s t two support+ pieces are left on ea* side ( ! place :]e x is int5d$ to make ! f9al b5d1 t b5d c be made 9 a flat-flame gas burn] )\t caus+ ! inn] tube to come 9 contact ) ! walls ( ! out] tube4 ,c>e mu/ be tak5 :5 jo9+ on ! side piece t ! inn] tube is n heat$ en\gh to fuse x4 ,! small hole 9 ! side ( ! out] tube is produc$ by heat+ & bur/+4 ,a ,liebig's ,cond5s]4--,?is consi/s ( a /raight glass tube pass+ ?r\gh an out] cool+ jacket4 ,9 practice x is bett] to make ! jacket z a sep>ate piece1 & to effect a wat]-tight junction by means ( two %ort rubb] tubes4 ,x may1 h[ev]1 be made ) two int]nal seals ( ! class describ$ "u ,a ,spray ,arre/]4 ,!re is mu* less risk ( ^! seals crack+ if ! inn] tube is made 9 ! =m ( a spiral or has a numb] ( bulbs bl[n on x 9 ord] to give a c]ta9 am\nt ( ela/icity4 ,a ,d\ble-,surface ,cond5s]4--,fig4 #aj %[s a cond5s] ( ?is nature :i* is suppli$ by ,messrs4 ,baird & ,tatlock4 ,x may be built up 9 /ages z %[n by a1 b1 & c1 b ! "w involv$ requires consid]able skill1 & ! majority ( laboratory work]s w f9d x *eap] to buy ?an to make4 ,illu/ration3 ,fig4 #aj ,a ,sph]ical ,cond5s]4--,su* a cond5s] z t %[n by f1 ,fig #aj1 involves a me?od :i* may f9d application 9 a numb] ( cases4 ,! out] bulb is bl[n f a ?ick piece ( tub+ :i* has be5 ins]t$ 9 a small] piece 7see d1 ,fig4 #f72 !n ! inn] bulb by simil> me?od4 ,x is n[ necess>y to introduce ! small] bulb into ! l>g]1 & = ?is purpose ! l>g] bulb mu/ be cut into halves4 ,a small b deep cut is made ) ! file or glass-bl[]s' knife 9 ! middle ( ! l>g] bulb1 & at "r angles to ! axis ( ! tube on :i* x is bl[n4 ,a m9ute bead ( int5sely heat$ glass is n[ br\ght 9 contact ) ! cut 9 ord] to />t a crack4 ,?is crack may n[ be l$ r\nd ! bulb z describ$ on page #cj4 ,if ! "w is c>ri$ out ) c>e1 x is possible to obta9 ! bulb 9 two halves z %[n by d1 & ^! two halves w correspond s exactly t :5 ! cut edges are plac$ 9 contact !y w be almo/ air-tight4 ,! two tubes f ! small] bulb %\ld be cut to su* a l5g? t !y w j re/ inside ! l>g]1 & ! ends %\ld be exp&$4 ,place ! inn] bulb 9 position & fit ! two halves ( ! out] bulb toge!r1 tak+ great c>e n to *ip ! edges4 ,if ! l5g? ( ! tubes on ! inn] bulb has be5 adju/$ prop]ly1 ! inn] bulb w be support$ 9 position by _! contact ) ! tubes on ! out] bulb4 ,n[ rotate ! crack$ portion ( ! out] bulb 9 front ( a bl[pipe flame & press ! halves toge!r v g5tly z ! glass s(t5s4 ,exp& slightly by bl[+ if necess>y4 ,if a small p9-hole develops at ! jo9t x is sometimes possible to close ?is ) a bead ( hot glass2 b if ! bulb has be5 cut prop]ly !re %\ld be no p9-holes =m$4 ,! cond5s] is f9i%$ by jo9+ on ! side tubes & seal+ ! inn] tube ?r\gh by ! me?ods already giv54 ,9 ord] to bl[ bulbs l>ge en\gh to make a useful cond5s]1 x w be conv5i5t to employ ! multiple-jet bl[pipe describ$ on page #d4 ,a ,soxhlet-,tube or ,extraction ,app>atus4--,?is involves ! con/ruction ( a re-entrant jo9 :]e ! syphon fl[s into ! l[] tube4 ,x is ( consid]able value z an ex]cise & ! complete app>atus is easy to make4 ,a l>ge tube is seal$ at ! bottom & ! top is lipp$1 z 9 mak+ a te/-tube4 ,a small] tube is !n jo9$ on by a me?od simil> to t giv5 on page #ah1 b )\t mak+ a p]=ation 9 ! bottom ( ! l>ge tube4 ,heat+ & exp&+ by air pressure1 fir/ ?r\gh ! l>ge tube1 !n ?r\gh ! small] tube & !n aga9 ?r\gh ! l>ge tube1 w give a satisfactory f9i% to ?is "p ( ! "w4 ,illu/ration3 ,fig4 #aa ,! syphon tube is n[ jo9$ on to ! l>ge tube z %[n by a1 ,fig4 #aa1 c>e be+ tak5 to seal ! o!r end ( ! syphon tube be=e jo9+4 ,! details ( ! f9al & re-entrant jo9t ( ! syphon tube are %[n at ! l[] "p ( a4 ,?is jo9 is made by exp&+ ! seal$ end ( ! syphon tube into a small1 ?ick-wall$ bulb1 & ! bottom ( ?is bulb is bur/ out by local heat+ & bl[+2 ! fragm5ts ( glass are remov$ & ! edges made smoo? by melt+4 ,a simil> op]ation is c>ri$ out on ! side ( ! tube to :i* ! syphon tube is to be jo9$4 ,?is /age is %[n by a4 ,n[ heat ! syphon tube at ! upp] b5d until x is flexible1 & press ! bulb at its end into ! op5+ on ! side ( ! o!r tube4 ,hold ! glass ?us until ! syphon is no long] flexible4 ,! f9al jo9 is made by heat+ ! two contact+ surfaces1 if necess>y press+ ! edges 9 contact ) ! end ( a turn-p91 fus+ toge!r & exp&+4 ,! f9i%$ app>atus is %[n by c4 ,electrodes4--,a ?9 plat9um wire may be seal$ into a capill>y tube )\t any special precautions be+ necess>y4 ,! capill>y tube may be drawn out f ! side ( a l>g] tube by heat+ a spot on ! glass1 t\*+ ) a glass rod & draw+ ! rod away2 or ! exhau/ion bran* describ$ on page #ah may be us$ = ! introduction ( an electrode4 ,x is conv5i5t sometimes to c>ry out ! exhau/ion ?r\gh ! same tube t w aft]w>ds s]ve = ! electrode4 ,! electrode wire is laid inside ! bran* be=e connect+ to ! exhau/ion pump4 ,:5 exhau/ion is complet$ ! tube is heat$ until ! s(t glass fl[s r\nd ! plat9um & makes ! seal air-tight4 ,! bran* is n[ cut (f close to ! seal on ! pump side1 a loop is made 9 ! project+ end ( ! plat9um wire1 & ! seal is f9i%$ by melt+ ! cut-(f end4 ,plat9um is usually employ$ = su* "w1 b if c>e is tak5 to avoid oxidation x is n impossible to make fairly satisfactory seals ) clean iron or nickel wire4 ,h>d rods ( f9e graphite1 su* z are us$ 9 "s p5cils1 may also be seal$ into glass1 b x seems probable t air w\ld diffuse ?r\gh ! graphite 9 ! c\rse ( "t4 ,ano!r me?od = ! introduction ( an electrode is illu/rat$ by d1 e1 f & g1 ,fig4 #aa4 ,9 ?is case ! bulb or ?9-wall$ tube into :i* ! electrode is to be seal$ is p]=at$ by a quick /ab ) an int5sely heat$ wire--pref]ably ( plat9um--:i* is !n )drawn be=e ! glass has _h "t to h>d51 & ?us a m9ute circul> hole is made4 ,! electrode is coat$ ) a lay] ( simil> glass1 or ( ! specially made enamel :i* is sold = ?is purpose1 ins]t$ into ! bulb or tube by any conv5i5t op5+1 & adju/$ by c>eful %ak+ until ! plat9um wire projects ?r\gh ! small hole4 ,! bulb or tube is !n fus$ to ! coat+ ( ! electrode & ! :ole spot exp&$ slightly by bl[+4 ,! appe>ance ( ! f9i%$ seal is %[n by g4 ,x is well to anneal slightly by smok+4 ,!rmomet]s4--,ap>t f ! notes on page #bj ) respect to ! bl[+ ( a suitable bulb on capill>y tub+ !re is little to say 9 connection ) ! glass work+ ne$$ 9 mak+ a pla9 !rmomet]4 ,! size desirable = ! bulb w be det]m9$ by ! bore ( ! capill>y tube1 ! coeffici5t ( expansion ( ! liquid us$ = fill+1 & ! range ( temp]ature = :i* ! !rmomet] is int5d$4 ,fill+ may be c>ri$ out z foll[s3--,fit a small funnel to ! op5 end ( ! capill>y by means ( a rubb] tube1 & p\r into ! funnel r m ?an en\gh ( ! liquid to be us$ ?an is requir$ to fill ! bulb4 ,m]cury or alcohol w be us$ 9 practice1 mo/ probably4 ,w>m ! bulb until a few air bubbles h escap$ ?r\gh ! liquid & !n all[ to cool4 ,?is w suck a c]ta9 am\nt ( liquid into ! bulb4 ,n[ heat ! bulb aga91 & at ! same "t heat ! capill>y tube ov] a second burn]4 ,! liquid w boil & sweep out ! residual air1 b x is necess>y to heat ! capill>y tube z well 9 ord] to prev5t cond5sation4 ,all[ ! bulb & tube to cool1 !n repeat ! heat+ once m4 ,by ?is "t ! bulb & tube %\ld be free f air1 & cool+ %\ld give a completely fill$ !rmomet]4 ,remove ! funnel & heat ! !rmomet] to a few degrees above ! maximum temp]ature = :i* x is to be us$2 ! m]cury or o!r fill+ liquid w ov]fl[ f ! top1 &1 z ! temp]ature falls1 w rec$e1 ?us all[+ ! end ( ! capill>y to be drawn out4 ,reheat aga9 until ! liquid rises to ! top ( ! tube1 !n seal by means ( ! bl[pipe flame4 ,! !rmomet] is n[ f9i%$ except = graduation2 ?is is dealt ) on page #ge4 ,an ,al>m ,!rmomet]4--,a !rmomet] :i* w complete an electric circuit :5 a c]ta9 temp]ature is rea*$ may be made by seal+ an electrode 9 ! bulb & introduc+ a wire into ! top1 :i* 9 ?is case is n seal$4 ,naturally1 ?is !rmomet] w be fill$ ) m]cury4 ,!re is consid]able difficulty 9 fill+ su* a bulb )\t caus+ x to crack4 ,sev]al elaborations ( ?is =m are made1 9 :i* electrodes are seal$ ?r\gh ! walls ( ! capill>y tube1 ?us mak+ x possible to detect electrically ! v>iation ( temp]ature :5 x exce$s any giv5 limits4 ,an ,enclos$ or ,float+ ,!rmomet]4--,! con/ruction ( ?is type ( !rmomet] is %[n by h & i1 ,fig #aa4 ,x is made 9 ! foll[+ /ages3--,a bulb is bl[n on ! drawn-out end ( a ?9-wall$ tube z %[n by h4 ,a small bulb is bl[n on ! end ( a capill>y tube1 bur/1 & turn$ out to =m a lip :i* w re/ 9 ! drawn-out "p ( ! ?9-wall$ tube b is j too l>ge to ent] ! bulb4 ,! capill>y tube is introduc$ & seal$ 9 position1 c>e be+ tak5 to exp& ! jo9t a little4 ,! !rmomet] is fill$ & ! top ( ! capill>y tube clos$ by ! use ( a small bl[pipe flame4 ,a pap] scale hav+ ! necess>y graduations is ins]t$1 & ! top ( ! out] tube is clos$ z %[n by i4 ,a ,maximum & ,m9imum ,!rmomet]4--,if a small dumb-bell-%ap$ rod ( glass or metal is introduc$ into ! capill>y tube ( a horizontally plac$1 m]cury-fill$ !rmomet] 9 su* a position t ! ris+ m]cury column w come 9 contact ) x1 ! rod w be pu%$ =w>d4 ,:5 ! m]cury falls aga9 ! rod w be left beh9d & ?us indicate ! maximum temp]ature atta9$4 ,if a simil> dumb-bell-%ap$ rod is introduc$ into an alcohol-fill$ !rmomet] & pu%$ d[n until x is )9 ! alcohol column1 x w be drawn d[n by surface t5sion z ! column falls2 b ! ris+ column w fl[ pass$ x )\t caus+ any displacem5t2 ?us ! m9imum temp]ature w be record$4 ,six's comb9$ maximum & m9imum !rmomet] is %[n by b1 ,fig4 #aa4 ,9 ?is case bo? maximum & m9imum records are obta9$ f a m]cury column1 al?\gh ! !rmomet] bulb is fill$ ) alcohol4 ,x is an advantage to make ! dumb-bell-%ap$ rods ( iron1 z ! !rmomet] c !n be reset by ! use ( a small magnet1 ano!r advantage consequ5t on ! use ( metal be+ t ! rods c be easily adju/$1 by slight b5d+1 s z to rema9 /ation>y 9 ! tubes :5 ! !rmomet] is hang+ v]tically1 & yet to move ) suffici5t fre$om to yield to ! pressure ( ! record+ column4 ,! !rmomet] may be fill$ by ! foll[+ me?od3--,:5 ! /raight tube has be5 made ! fir/ dumb-bell is introduc$ & %ak5 d[n well t[>ds ! l[] bulb1 ! tube is n[ b5t to its f9al %ape & ! :ole !rmomet] fill$ ) alcohol z describ$ on page #dd4 ,n[ heat ! !rmomet] to a little above ! maximum temp]ature t x is int5d$ to record1 & p\r clean m]cury into ! op5 bulb :ile hold+ ! !rmomet] v]tically4 ,all[ to cool1 & ! m]cury w be suck$ d[n4 ,! second dumb-bell is n[ introduc$1 suffici5t alcohol be+ all[$ to rema9 9 ! op5 bulb to ab\t half fill x1 & ! alcohol 9 ?is bulb is boil$ to expel air4 ,! tube ?r\gh :i* ! bulb 0 fill$ 9 n[ seal$4 ,cl9ical ,!rmomet]s4--,! cl9ical !rmomet] is a maximum !rmomet] ( a diff]5t type4 ,9 ?is case !re is a con/riction ( ! bore at a po9t j above ! bulb4 ,:5 ! m]cury 9 ! bulb comm5ces to contract1 ! m]cury column breaks at ! con/riction & rema9s /ation>y 9 ! tube1 ?us %[+ ! maximum temp]ature to :i* x has ris54 ,vacuum ,tubes4--,!re are s _m =ms ( ^! t x is sc>cely practicable or desirable to give detail$ in/ructions = mak+ !m2 b an application ( ! v>i\s me?ods ( glass-work+ :i* h already be5 expla9$ %\ld enable ! /ud5t to con/ruct mo/ ( ! simpl] v>ieties4 ,an int]e/+ vacuum tube is made :i* has no electrodes1 b conta9s a quantity ( m]cury4 ,:5 ! tube is rock$ s z to cause friction betwe5 ! m]cury & ! glass suffici5t *>ge is produc$ to cause ! tube to gl[4 ,a ,spr5gel ,pump4--,?is1 9 its simple/ =m1 is illu/rat$ by a1 ,fig4 #ab4 ,su* a =m1 al?\gh highly satisfactory 9 action1 ne$s con/ant wat*+ :ile 9 action1 z %\ld ! m]cury funnel become empty air w ent] ! exhau/$ vessel4 ,obvi\sly1 ! fall-tube mu/ be made n less ?an ?irty in*es long2 ! measurem5t be+ tak5 f ! junction ( ! exhau/ion bran* ) ! fall-tube to ! top ( ! turn$-up end4 ,illu/ration3 ,fig4 #ab ,a ,macleod ,pump4--,"o =m ( ?is is illu/rat$ by b1 ,fig4 #ab4 ,x has ! advantage t ! m]cury res]voir may be all[$ to become empty )\t affect+ ! vacuum 9 ! vessel be+ exhau/$4 ,sp9n+ ,glass4--,by ! use ( suitable appliances1 x is q possible to draw out a cont9u\s ?read ( glass1 :i* is s ?9 z to h almo/ ! flexibility & app>5t s(tness ( wooll5 fibre2 a mass ( su* ?reads con/itutes ! glass wool ( comm]ce4 ,! appliances necess>y are3--a bl[pipe capable ( giv+ a well-=m$ flame ( ab\t six or eight in*es 9 l5g?1 a :eel ( f eighte5 in*es to ?ree feet 9 diamet] & hav+ a flat rim ( ab\t ?ree in*es wide1 & a device = rotat+ ! :eel at a spe$ ( ab\t ?ree hundr$ revolutions p] m9ute4 ,a v satisfactory arrangem5t may be made f an old bicycle2 ! back :eel hav+ ! tyre remov$ & a flat rim ( t9 fa/5$ on 9 its place4 ,! *a9 drive %\ld be reta9$1 b "o ( ! cranks remov$ & a h&le sub/itut$ = ! rema9+ p$al4 ,! :ole device is %[n by ,fig4 #ac4 ,illu/ration3 ,fig4 #ac ,! proc$ure 9 sp9n+ glass is z foll[s3--,fir/ melt ! end ( a glass rod & obta9 a l>ge mass ( ?or\ghly s(t5$ glass1 n[ sp9 ! :eel at su* a spe$ t its own mom5tum w keep x sp9n+ = sev]al seconds4 ,t\* ! end ( ! melt$ rod ) ano!r piece ( glass &1 )\t )draw+ ! orig9al rod f ! bl[pipe flame1 draw out a ?read ( molt5 glass & twi/ x r\nd ! sp9n+ :eel4 ,if ?is is done prop]ly1 ! ?read ( glass w grip on ! flat rim1 & by cont9u+ to turn ! :eel by h& x is possible to draw out a cont9u\s ?read f ! melt$ rod1 :i* mu/ be advanc$ 9 ! bl[pipe flame z x is drawn on ! :eel4 ,if ! rod is n advanc$ suffici5tly ! ?read w melt (f1 if x is advanc$ too mu*1 s z to heat ! ?ick "p & all[ ! glass to become too cool at ! po9t ( draw+ out1 !n ! ?read w become too ?ick1 b x is easy aft] a little practice to obta9 ! "r conditions4 ,practice is necess>y also 9 ord] to f9d ! "r spe$ = ! :eel4 ,:5 suffici5t glass has be5 spun1 ! :ole hank ( ?9 ?read may be remov$ by draw+ ! ?umb-nail across ! :eel at any po9t on its flat rim1 ?us break+ ! ?reads1 & all[+ ! hank to op54 ,bru%es = ,use ) ,/rong ,acids4--,glass wool1 if ( f9e en\gh texture to be highly flexible1 c be us$ to make acid-resi/+ bru%es4 ,a conv5i5t me?od = m\nt+ ! spun glass is to melt ! ends ( ! ?reads toge!r into a bead1 & !n to fuse ! bead on to a rod2 ?us giv+ a bru%4 ,if a po9t$ bru% is necess>y1 ! po9t may be gr\nd on an ord9>y gr9d/one or c>borundum :eel by press+ ! loose end ( ! spun glass aga9/ ! gr9d+ :eel ) a ?9 piece ( c>dbo>d4 ,:5 us+ bru%es ( ?is description1 x is well to be> 9 m9d ! fact t !re is always a liability ( a few ?reads ( glass break+ (f dur+ use4 ,,*apt] ,,iv ,glass1 ,its ,composition & ,*>act]i/ics4 ,anneal+4 ,drill+1 ,gr9d+1 & ,%ap+ ,glass by me?ods o!r ?an ,fusion4 ,/opcocks4 ,m>k+ ,glass4 ,calibration & ,graduation ( ,app>atus4 ,!rmomet]s4 ,exhau/ion ( ,app>atus4 ,jo9+ ,glass & ,metal4 ,silv]+ ,glass4 ,!re are ?ree k9ds ( glass rod & tub+ :i* are easily obta9able2 ^! are soda-glass1 :i* is t usually suppli$ by *emical app>atus deal]s :5 no p>ticul> glass is specifi$2 combu/ion-glass1 :i* is suppli$ = "w requir+ a glass t does n s easily s(t5 or fuse z soda-glass2 & lead-glass1 :i* is less common4 ,!re are also resi/ance-glass1 made = use :]e v slight solubility 9 wat] or o!r solutions is desirable1 & a numb] ( o!r special glasses2 b ( ^! soda-glass1 combu/ion-glass1 lead-glass1 & resi/ance-glass are ! mo/ important to ! glass-bl[] ^: "w is connect$ ) laboratory ne$s4 ,soda-,glass4--,consi/s *iefly ( sodium silicate1 b conta9s small] quantities ( alum9um silicate1 & (t5 ( calcium silicate2 !re may also be traces ( sev]al o!r comp\nds4 ,! ord9>y soda-glass tub+ melts easily 9 ! bl[pipe flame1 x has n a long int]m$iate or visc\s /age dur+ fusion1 b becomes highly fluid r sudd5ly2 x does n black5 9 ! r$uc+ flame4 ,bad soda-glass or t :i* has be5 kept = _m ye>s1 t5ds to devitrify :5 work$4 ,t is to say ! glass becomes m or less cry/all9e & infusible :ile x is 9 ! flame2 & 9 ?is case x is (t5 impossible to d good "w ) t p>ticul> sample ( glass2 al?\gh ! devitrification may sometimes be rem$i$ by heat+ ! devitrifi$ glass to a high] temp]ature4 ,! pres5ce ( alum9um comp\nds appe>s to h "s influ5ce on ! t5d5cy ( ! glass to resi/ devitrification4 ,soda-glass1 z a rule1 is m liable to crack by sudd5 heat+ ?an lead-glass1 & articles made f soda-glass (t5 t5d to crack spontane\sly if badly made or1 9 ! case ( heavi] & ?ick] articles1 if insuffici5tly anneal$4 ,combu/ion-,glass4--,is usually a glass conta9+ m calcium silicate & potassium silicate ?an ! ord9>y s(t soda-glass4 ,x is mu* less fusible ?an ord9>y soda-glass1 & passes ?r\gh a long] int]m$iate or visc\s /age :5 heat$4 ,su* a glass is n v suitable = use ) ! bl[pipe ow+ to ! difficulty exp]i5c$ 9 obta9+ a suffici5tly high temp]ature4 ,if1 h[ev]1 a c]ta9 am\nt ( oxyg5 is mix$ ) ! air us$ 9 produc+ ! bl[pipe flame ?is difficulty is m9imis$4 ,resi/ance-,glass4--,may conta9 z9c1 magnesium1 & o!r sub/ances4 ,z a rule x is h>d] ?an ord9>y soda-glass1 & less suitable = work+ 9 ! bl[pipe flame4 ,x %\ld h v little t5d5cy to dissolve 9 wat]1 & h5ce is us$ :5 traces ( alkali or silicates w\ld prove injuri\s 9 ! solutions = :i* ! glass vessels are to be us$4 ,lead-,glass4--,?is1 or fl9t glass z x is (t5 call$ f ! fact t silica 9 ! =m ( cru%$ & calc9$ fl9t 0 (t5 us$ 9 mak+ ! ,engli% lead-glasses1 conta9s a consid]able proportion ( lead silicate4 ,su* a glass has1 usually1 a p>ticul>ly bright appe>ance1 a high refractive index1 & is specially suitable = ! production ( ! heavy cut-glass w>e4 ,lead-glass tub+ is easy to "w 9 ! bl[pipe flame1 melts easily1 b does n become fluid q s sudd5ly z mo/ soda-glasses2 articles made f x are rem>kably /able & free f t5d5cy to spontane\s crack+1 al?\gh1 z is ess5tial = all ! heavy or glass-h\se "w1 ! massive articles ne$ anneal+ 9 ! ov54 ,! two *ief disadvantages ( lead-glass = laboratory "w are t x is black5$ by ! r$uc+ gases if held too ne> to ! blue cone ( ! bl[pipe flame1 & t x is r easily attack$ by *emical reag5ts2 ?us ammonium sulphide w cause black5+4 ,! effect ( ! r$uc+ flame on lead is n altoge!r a disadvantage1 h[ev]2 because a little c>e 9 adju/+ ! bl[pipe & a little c>e 9 hold+ ! glass 9 ! "r position w enable ! /ud5t to "w lead-glass )\t produc+ ! fa9te/ trace ( black5+4 ,?is1 9 addition to be+ a valuable ex]cise 9 manipulation1 w tea* him to keep 8 bl[pipe 9 good ord]1 & prove a useful aid 9 8 e>ly ef=ts to judge z to ! condition ( ! flame4 ,x prev5ts disc\ragem5t if ! /ud5t does 8 prelim9>y "w ) ! soda-glass1 b he %\ld c]ta9ly make exp]im5ts ) lead-glass z soon z he has acquir$ reasonable dext]ity ) soda-glass4 ,anneal+4--,anneal+ is a process by :i* any condition ( /ra9 :i* has be5 set up 9 a glass article1 ei!r by rapid cool+ ( "o "p :ile ano!r "p /ill rema9s hot1 or by ! application ( me*anical /ress aft] cool+ is reliev$4 ,anneal+ is c>ri$ out by subject+ ! article to a temp]ature j bel[ ! s(t5+ po9t ( ! glass1 ma9ta9+ t temp]ature until ! :ole article has become heat$ ?r\gh ! ?ick] "p1 & !n r$uc+ ! temp]ature v gradually2 ?us avoid+ any m>k$ cool+ ( ! ?9n] & out] p>ts fir/4 ,= ?9 glass app>atus ( ! lamp-bl[n or bl[pipe-made v>iety 9 :i* !re are no m>k$ diff]5ce ( ?ickness1 su* z jo9s on tubes1 ord9>y seals1 bulbs1 etc41 !re is little ne$ = anneal+2 & ev5 ^? hav+ r m>k$ *anges ( ?ickness1 su* z filt] pumps1 c be anneal$ suffici5tly by tak+ c>e t ! la/ /ep 9 mak+ is heat+ to j bel[ visible r$ness 9 ! bl[pipe flame & !n rotat+ 9 a sooty gas flame until cov]$ ) a deposit ( c>bon4 ,! article %\ld !n be all[$ to cool 9 a place free f draughts & :]e ! hot glass w n come 9 contact ) any?+4 ,a few ( ! bl[pipe-made articles1 su*1 = example1 z glass /opcocks1 ne$ m c>eful anneal+1 & = ?is purpose a small %eet-iron ov5 :i* c be heat$ to dull r$ness ov] a collection ( gas burn]s w s]ve4 ,bett] /ill1 a small clay muffle c be us$4 ,9 ei!r case1 ! article to be anneal$ %\ld be laid on a clean1 smoo?1 fireclay surface1 ! temp]ature %\ld be ma9ta9$ at a v dull r$ = two or ?ree h\rs & !n r$uc$ /eadily until ! ov5 is cold4 ,?is cool+ %\ld take any?+ f ?ree to twelve h\rs1 accord+ to ! nature ( ! article to be anneal$4 ,a ?ick article1 or "o hav+ great irregul>ities 9 ?ickness w ne$ mu* long] anneal+ ?an "o ?9n] or m regul>4 ,z a rule1 soda-glass w ne$ m anneal+ ?an lead-glass4 ,drill+ ,glass4--,small holes may be drill$ 9 glass by means ( a rod ( h>d /eel :i* has be5 brok5 (f1 ?us giv+ a m or less irregul> & cry/all9e end4 ,!re are sev]al conditions necess>y to enable ! drill+ ( small holes to be c>ri$ out successfully3--! fir/ ( ^! is t ! drill %\ld be driv5 at a high spe$4 ,?is may be done by means ( a ge>$ h&-drill su* z ! ,am]ican patt]n drill1 al?\gh a some:at high] spe$ ?an ?is w give is ev5 m satisfactory4 ,! second condition is t ! pressure on ! drill is nei!r too light nor too heavy2 ?is is conv5i5tly regulat$ by h&4 ,! ?ird condition is t ! drill be prev5t$ f /ray+ ov] ! surface ( ! glass2 = ?is purpose a small metal guide is useful4 ,! f\r? condition is t a suitable lubricant be us$2 a /rong solution ( camphor 9 oil ( turp5t9e is p]haps ! mo/ suitable4 ,= comm]cial "w1 a diamond drill is (t5 us$1 b ?is is sc>cely necess>y = ! occasional "w ( a laboratory4 ,l>g] ,holes 9 ,glass4--,! me?od ( drill+ ) a h>d /eel rod is n highly satisfactory = any?+ b small holes4 ,:5 a l>g] hole1 say "o ( an eigh? ( an in* or m1 is ne$$ x is bett] to use a copp] or brass tube4 ,?is tube may be held 9 an ,am]ican h&-drill1 b a mixture ( c>borundum or em]y & wat] is suppli$ to ! rotat+ end4 ,tube or drill mu/ be lift$ at frequ5t int]vals 9 ord] to all[ a fre% supply ( ! gr9d+ mat]ial to rea* ! end4 ,9 ?is case1 also1 a guide is q ess5tial 9 ! e>ly /ages ( drill+2 o!rwise ! end ( ! tube w /ray4 ,! spe$ ( cutt+ may be increas$ slightly by mak+ a numb] ( radial slots 9 ! end ( ! tube2 ^! s]ve to hold a supply ( ! gr9d+ mat]ial4 ,gr9d+ ,l5ses4--,?is is sc>cely )9 ! scope ( a book on glass-bl[+ = laboratory purposes1 b x may be said t ! l5s may be gr\nd by means ( a p]mutat+ m\ld ( h>d lead or type-metal4 ,! r\gh %ap+ is done ) co>se c>borundum or em]y1 & successive /ages are c>ri$ on ) f9] & f9] mat]ial4 ,! la/ poli%+ is by ! use ( jewell]s' r\ge on ! m\ld1 n[ l9$ ) a f9e textile4 ,fil+ ,glass4--,if a new file1 ?or\ghly lubricat$ ) a solution ( camphor 9 oil ( turp5t9e1 is us$1 !re is b little difficulty 9 fil+ ! s(t] glasses4 ,a sl[ movem5t ( ! file1 )\t excessive pressure b )\t all[+ ! file to slip1 is desirable4 ,aft] a "t ! cutt+ edges ( ! file tee? w we> d[n & x w be necess>y to replace ! file by ano!r4 ,gr9d+ ,/opp]s4--,?is is1 p]haps1 ! mo/ common =m ( gr9d+ t ! laboratory work] w ne$ to p]=m1 & = t reason1 r full details ( ! proc$ure are desirable4 ,a v crude =m ( gr\nd-9 /opp] may be made by draw+ out ! neck & ! mass ( glass :i* is int5d$ to =m ! /opp] to approximately correspond+ angles1 wett+ ! surfaces ) a mixture ( ! abrasive mat]ial & wat]1 & gr9d+ ! /opp] 9 by h&4 ,frequ5t lift+ ( ! /opp] is necess>y dur+ gr9d+1 9 ord] to all[ fre% supplies ( abrasive mat]ial to rea* ! contacts4 ,:5 an approximate fit is obta9$1 ! co>se abrasive %\ld be wa%$ (f1 c>e be+ tak5 t ! wa%+ is complete1 & a f9] abrasive sub/itut$4 ,aft] a :ile1 ?is is replac$ 9 its turn by a /ill f9] gr9d+ mat]ial4 ,su* a me?od ( gr9d+ may give a satisfactory /opp]+ if ! angles ( ! plug & socket correspond v closely be=e gr9d+ is comm5c$2 b if !re is a wide diff]5ce 9 ! orig9al angles1 !n no am\nt ( gr9d+ by ?is me?od w produce a good result4 ,! reason = ?is is t ! plug w become s worn 9 ! prelim9>y gr9d+ z to assume ! =m ( a highly truncat$ cone2 ! socket w assume a rev]se =m1 & ! end result w be a loose-fitt+ plug & socket4 ,satisfactory gr9d+ may be c>ri$ out by ! use ( copp] or type-metal cones = ! prelim9>y %ap+4 ,su* cones %\ld be m\nt$ on a m&rel :i* w fit into ! *uck ( ! ,am]ican h&-drill & turn$ on ! la! to ! desirable angle = /opp]+4 ,a numb] ( ^! cones w be necess>y4 ,a numb] ( simil> m\lds1 t is to say blocks ( type-metal or h>d lead 9 :i* is a hole correspond+ 9 size & angle to ! plug desir$1 %\ld be made also4 ,^! mu/ be rotat$1 ei!r 9 ! la! or by o!r means1 & are us$ = ! prelim9>y %ap+ ( ! plug4 ,if b few plugs are to be gr\nd x is unnecess>y to provide a means ( rotat+ ! m\lds1 z ! plug may be held 9 ! h& & gr\nd into ! m\ld 9 a mann] simil> to t us$ 9 ! fir/ me?od ( /opp]+4 ,illu/ration3 ,fig4 #ad ,:5 ! socket & plug h be5 gr\nd1 by ! successive use ( cones & m\lds1 to ! desir$ angle1 s t !y correspond almo/ exactly1 ! plug is giv5 its f9al fitt+ into ! socket by gr9d+-9 ) a f9e abrasive1 9 ! mann] fir/ describ$4 ,/opcocks4--,al?\gh x w\ld be m /rictly 9 keep+ ) ! =m ( ?is book to divide ! mak+ ( /opcocks into two p>ts2 %ap+ by heat & gr9d+1 we w consid] ! :ole op]ation "h1 & take = our example a simple /opcock su* z t illu/rat$ by ,fig4 #ad4 ,! blank1 f1 t is ! socket be=e gr9d+1 is made by draw+ out a piece ( fairly ?ick-wall$ tub+ into ! =m %[n by a4 ,two zones on ?is tube are !n heat$ by means ( a small1 po9t$ flame1 & ! tube is compress$ along its axis1 ?us produc+ two rais$ r+s z %[n by b4 ,two zones1 slightly t[>ds ! out] sides ( ^! two rais$ r+s are heat$ & ! tube is drawn :ile air pressure is ma9ta9$ )94 ,?is produces two ?9-wall$ bulbs or ext5sions simil> to ^? %[n by c4 ,"o ( ^! ext5sions is n[ brok5 (f by means ( a %>p bl[ ) ! edge ( a file or o!r piece ( metal1 & ! edges ( ! brok5 glass are r\nd$ 9 ! flame4 ,! o!r ext5sion is left to s]ve z a h&le4 ,we h n[ a piece ( glass l t %[n by d4 ,n[ heat a spot on ! side ( ?is1 m$ially betwe5 ! rais$ r+s1 until ! glass is on ! po9t ( becom+ de=m$1 & br+ ! int5sely heat$ end ( a small] tube 9 contact ) ! heat$ spot4 ,)\t di/urb+ ! relative positions ( ! two tubes1 press ! small] tube d[n on a ?9 /eel wire1 s t ! wire passes along ! tube & ent]s ! s(t glass2 ?us =m+ a projection inside ! sockets z %[n by e4 ,! wire mu/ be )drawn1 aga9 imm$iately4 ,:5 ! wire has be5 )drawn1 heat ! place :]e x ent]$ to dull r$ness1 9 ord] to relieve any /ra92 break (f ! ?9 ext5sion1 :i* up to ! pres5t has s]v$ z a h&le1 r\nd (f ! brok5 edges 9 ! flame1 & jo9 on & ind5t a simil> piece ( small tub+ to ! opposite side ( ! socket2 ! socket at ?is /age be+ %[n by f4 ,! blank = ! socket is n[ complet$1 b x mu/ be heat$ to dull r$ness 9 ord] to relieve /ra9 & be plac$ 9 an anneal+ ov51 :]e x %\ld be anneal$ = "s h\rs4 ,! blank = ! plug (f]s no special difficulty2 x is made by heat+ a glass rod & compress+ x axially until a mass hav+ ! =m %[n by g1 ,fig4 #ad1 is produc$2 ! end ( ?is is heat$ int5sely & br\ght 9 contact ) ! r less heat$ side ( a glass tube :i* has be5 drawn to ! %ape desir$ = ! h&le2 :5 contact is made a slight air pressure is ma9ta9$ 9 ! glass tube1 ?us produc+ a holl[ jo94 ,! ends ( ! tube are seal$ & ! bottom ( ! plug is drawn (f1 ?us giv+ ! f9i%$ blank z %[n by h4 ,?is blank is n[ held 9 a pair ( asbe/os-cov]$ tongs1 heat$ to dull r$ness all ov]1 & transf]r$ to ! anneal+ ov54 ,:5 cold1 ! socket is gr\nd out by ! second me?od giv5 "u ,gr9d+ ,/opp]s2 t is to say1 by means ( type-metal or copp] cone1 & ! plug is gr\nd to fit 9 a correspond+ m\ld4 ,:5 ! fit is almo/ p]fect1 ! transv]se hole is drill$ 9 ! plug1 & ! f9al f9i%+ is made ) f9e abrasive p[d]4 ,great c>e mu/ be tak5 9 ! f9al gr9d+ t !re is no accumulation ( abrasive mat]ial 9 ! transv]se hole ( ! plug2 if ?is is all[$ to occur !re w be a r+ gr\nd out ( ! socket :]e ! holes move1 & ! tightness ( ! f9i%$ /opcock w be lo/4 ,m>k+ ,glass4--,z a prelim9>y to a consid]ation ( ! me?ods ( graduat+ & calibrat+ glass app>atus1 x is conv5i5t to consid] ! v>i\s me?ods :i* are available = m>k+ glass4 ,among ^! are1 ! writ+ diamond1 ! c>borundum or abrasive p5cil1 ! cutt+-:eel1 & et*+ by means ( hydr(luoric acid4 ,ea* produces a diff]5t class ( m>k+ & ea* is wor?y ( indep5d5t consid]ation4 ,! ,writ+ ,diamond4--,?is is ! "n giv5 to a small irregul> fragm5t ( bort :i* is usually m\nt$ 9 a ?9 brass rod4 ,su* a diamond1 if prop]ly select$1 has none ( ! *>act]i/ics ( a cutt+ diamond2 al?\gh "o occasionally f9ds s-call$ writ+ diamonds :i* w produce a def9ite cut4 ,^! %\ld be reject$4 ,! writ+ diamond is us$ 9 mu* ! same way z a p5cil1 b is held m p]p5dicul>ly to ! object1 & a c]ta9 am\nt ( pressure is necess>y4 ,! m>k produc$ is a ?9 scrat* :i*1 al?\gh fairly def9ite1 lacks bread?1 & ?is is a disadvantage :]e ! m>k+ has to be read at a di/ance4 ,?is disadvantage may to "s ext5t be ov]come by mak+ a numb] ( p>allel scrat*es4 ,! ,abrasive ,p5cil4--,a rod ( c>borundum composition may be gr\nd or fil$ to a po9t1 & ?is =ms a v useful p5cil = g5]al "w4 ,! m>k+ produc$ is r less def9ite ?an t produc$ by a writ+ diamond1 b has ! advantage ( be+ broad]4 ,! ,cutt+ ,:eel4--,cutt+ 9 ?is case is sc>cely ! ideal expression1 x %\ld r be gr9d+1 b cutt+ is m commonly us$4 ,exce$+ly good graduations may be made by ! edge ( a small1 ?91 abrasive :eel :i* is m\nt$ on ! end ( a small m&rel & driv5 by a flexible %aft f an electric motor or any o!r conv5i5t s\rce ( p[]4 ,! dep? ( ! m>k c be controll$1 & v light pressure w suffice4 ,et*+4--,?is is (t5 ! quicke/ & easie/ way ( m>k+ glass app>atus4 ,! object to be m>k$ %\ld fir/ be w>m$ & coat$ v ?or\ghly ) a ?9 film ( p>aff9 wax4 ,:5 cold1 ! m>k+ is made ?r\gh ! p>aff9 wax by means ( a ne$le po9t1 & ! object is !n expos$ to ! action ( hydr(luoric acid4 ,if a %all[ b cle>ly visible m>k+ is desir$1 x is well to use ! vap\r ( ! acid2 ?is may be done by b5d+ up a %eet-lead tr\gh on :i* ! object c re/ ) ! m>k$ surface d[nw>ds4 ,a little ( ! comm]cial hydr(luoric acid1 or a mixture ( a fluoride & sulphuric acid1 is di/ribut$ ov] ! bottom ( ! tr\gh1 & ! :ole arrangem5t is all[$ to /& = ab\t an h\r4 ,! object is wa%$ ?or\ghly & ! p>aff9 wax remov$1 ei!r by melt+ & wip+ (f or by ! use ( a solv5t1 & ! m>k+ is f9i%$4 ,if a deep m>k+ is desir$1 9 ord] t x may aft]w>ds be fill$ ) "s pigm5t1 a bett] result is obta9$ by ! use ( liquid comm]cial hydr(luoric acid1 :i* is a solution ( hydrog5 fluoride 9 wat]4 ,! acid is mopp$ on to ! object aft] ! m>k+s h be5 made on ! p>aff9 wax film1 & all[$ to rema9 9 contact = a few m9utes4 ,x is advantage\s to repeat ! mopp+-on process at int]vals dur+ ! et*+4 ,9 all cases :]e hydr(luoric acid is us$1 or /or$1 x is ( great importance to keep x well away f any optical in/rum5ts1 z ! mo/ m9ute trace ( vap\r 9 ! air w produce a highly de/ructive corrosion ( any glass surfaces4 ,me?ods ( ,calibration4--,9 ! case ( app>atus = volumetric "w1 ?is is usually c>ri$ out by weigh+1 al?\gh "s ( ! small] subdivisions are (t5 made by measurem5t4 ,:5 ! subdivisions are made 9 ?is way x is ( importance to see t ! walls ( ! tube or vessel to be calibrat$ are p>allel4 ,great errors arise 9 "s ( ! comm]cial app>atus f neglect ( ?is precaution4 ,a conv5i5t me?od ( te/+ = p>allelism1 9 ! case ( a wide tube1 is to close "o end & to weigh 9 successive quantities ( m]cury4 ,an obs]vation ( ! l5g? occupi$ by ea* successive quantity w indicate any *ange 9 ! bore4 ,9 ! case ( capill>y tubes1 x is conv5i5t to introduce an unweigh$ quantity ( m]cury1 measure its l5g? accurately1 & !n to move x along ! tube 9 /ages1 ei!r by tilt+ ! tube or by ! application ( air pressure4 ,a measurem5t ( ! l5g? at ea* /age w indicate :e!r ! bore is approximately p>allel or n4 ,nei!r ( ^! me?ods is to be reli$ on )\t a c>eful exam9ation ( ! tube1 z x may happ5 t !re are local irregul>ities 9 ! bore :i* comp5sate = ea* o!r1 & d n1 !re=e1 affect ! volume ( a giv5 l5g?4 ,obvi\sly1 ! small] ! quantity ( m]cury ) :i* ! te/ is c>ri$ out & ! great] ! numb] ( obs]vations made1 ! less risk w !re be ( su* an error4 ,a liquid1 su* z wat] or alcohol1 :i* wets ! glass is n suitable = su* a te/1 unless special precautions are tak54 ,:51 h[ev]1 a pipette or burette has to be calibrat$ to deliv] a c]ta9 volume ( wat]1 ! f9al calibration mu/ be made ) ?is liquid4 ,?us1 ! burette w\ld fir/ be calibrat$ by weigh+ 9 def9ite quantities ( m]cury ( say #ac4ed grammes 7#a cc at #ae;,c471 ea* ( ! #a cc divisions %\ld be m>k$ by "s tempor>y m>k+4 ,! burette is n[ fill$ ) a solution ( potassium bi*romate & sulphuric acid & all[$ to soak = "s "t2 ! bi*romate is wa%$ out & di/ill$ wat] is put 94 ,successive quantities ( wat] are run out ( ! jet1 a fix$ "t be+ all[$ = dra9+1 & ! weights ( ! quantities deliv]$ are not$4 ,?is proc$ure w give ! necess>y data = alt]+ ! m>k+ s t x may correspond to #a cc deliv]$4 ,ea* #a cc division is n[ divid$ into t5?s by ! me?od describ$ bel[4 ,a f9al v]ification ( ! m>k+s %\ld be made :5 ! subdivision is complet$4 ,subdivision ( ,graduations4--,m>k out ! spaces to be subdivid$ on a %eet ( pap]4 ,take a reliable rul] on :i* any conv5i5t l5g? is divid$ into ! desir$ numb] & place x across ! l9es at su* an angle t ! limits not$ on ! rule exactly bridge ! gap4 ,n[ draw p>allel l9es ?r\gh ! m>k+s4 ,copy+ a ,scale4--,:5 a scale has be5 prep>$ on pap] & x is necess>y to copy t scale on ! wax$-glass surface = et*+1 a conv5i5t me?od is to employ a long wood5 b> hav+ a %>p ne$le pass+ ?r\gh x at ei!r end4 ,! scale & object to be m>k$ are fa/5$ 9 l9e ) "o ano!r1 & ! calip] b> is us$ f /ep to /ep4 ,! m>k is made by mov+ ! b> ?r\gh a m9ute portion ( a circle1 :i* provid$ t ! b> is two or ?ree feet 9 l5g?1 w n introduce any p]ceptible error 9 a scale ( say a qu>t] ( an in* 9 wid?4 ,! arrangem5t is %[n by ,fig4 #ae4 ,illu/ration3 ,fig4 #ae ,graduat+ a ,!rmomet]4--,assum+ t ! !rmomet] has be5 made ( c>efully select$ tub+ 9 :i* ! bore is p>allel & free f any small irregul>ities1 we h only to fix ! freez+ po9t & boil+ po9t4 ,! int]v5+ space may !n be divid$ into #ajj 7if ! !rmomet] is to be ,c5tigrade7 or #ahj 7if ,fahr5heit74 ,?is division may be c>ri$ out by ! me?od giv5 "u ,subdivisions ( ,graduations4 ,a !rmomet] %\ld n be calibrat$ until "s weeks aft] mak+1 z ! glass bulb t5ds to contract4 ,jo9+ ,glass & ,metal4--,x sometimes happ5s t "o ne$s to make a m p]man5t & less flexible jo9t betwe5 a glass & metal tube ?an c be obta9$ by means ( a rubb] tube4 ,to ?is end1 any "o ( ?ree slightly diff]5t me?ods may be employ$4 ,9 ! me?od ( ,*ateli] "o fir/ coats ! glass ) plat9um or silv]1 :i* may be done by moi/5+ ! glass ) plat9um *loride or silv] nitrate & !n heat+ to r$ness2 a lay] ( copp] is !n deposit$ electrolytically on ! treat$ surface ( ! glass1 & sold]+ is c>ri$ out 9 ! usual mann]4 ,mc,kelvy & ,taylor call att5tion to two o!r me?ods 9 ! ,j\rnal ( ! ,*emical ,society = ,septemb]1 #aibj4 ,9 "o ( ^! me?ods ! glass is coat$ ) plat9um by cov]+ x ) a susp5sion ( plat9um *loride 9 oil ( lav5d] & heat+ until ! oil is burnt (f4 ,! metal tube is !n t9n$ on its inn] side & sold]$ to ! prep>$ glass1 slightly acid z9c *loride be+ us$ z a flux4 ,9 ! second me?od1 a jo9t is made by means ( ! ,kraus flux1 :i* consi/s ( equal weights ( z9c oxide1 borax1 & p[d]$ soda-glass fus$ toge!r4 ,?is is coat$ on ! inn] surface ( ! metal tube1 & ! hot glass tube1 :i* has _h ! end slightly flang$ to give support1 is ins]t$4 ,fusion ( ! flux is complet$ by heat+ ! outside ( metal tube4 ,silv]+ ,glass4--,9 all cases :]e x is int5d$ to deposit a silv] mirror on a glass surface1 ?or\gh clean+ is ess5tial4 ,prolong$ soak+ 9 a hot solution ( potassium bi*romate :i* has be5 acidifi$ ) sulphuric acid w (t5 prove useful4 ,! glass %\ld !n be wa%$ ?or\ghly1 r9s$ 9 di/ill$ wat]1 & ! solution %\ld !n be us$4 ,!re are _m =mul = ! silv]+ solution1 b t us$ 9 ,m>t9's me?od may be giv53-- ,a--,nitrate ( ,silv] #dj grammes ,di/ill$ ,wat] #ajjj c4 cm4 ,b--,nitrate ( ,ammonium #fj grammes ,di/ill$ ,wat] #ajjj c4 cm4 ,c--,pure ,cau/ic ,pota% #ajj grammes ,di/ill$ ,wat] #ajjj c4 cm4 ,d--,pure ,sug> ,c&y #ajj grammes ,di/ill$ ,wat] #ajjj c4 cm4 ,dissolve & add3-- ,t>t>ic ,acid #bc grammes ,boil = t5 m9utes1 & :5 cool add3-- ,alcohol #bjj c4 cm4 ,di/ill$ ,wat] to #bjjj c4 cm4 ,= use take equal p>ts ( ,a & ,b4 ,mix toge!r also equal p>ts ( ,c & ,d 9 ano!r vessel4 ,!n mix bo? liquids toge!r 9 ! silv]+ vessel & susp5d ! glass to be silv]$ face d[nw>ds 9 ! solution4 ,or if a vessel has to be silv]$ on ! inside1 ! solution is p\r$ 94 ,9 ?is case1 ! deposition ( silv] may be ha/5$ by imm]s+ ! vessel to be silv]$ 9 w>m wat]4 ,9 work+ ) a silv] solution conta9+ ammonia or ammonium salts !re is sometimes ! possibility ( =m+ an explosive silv] comp\nd4 ,x is well1 !re=e1 to avoid keep+ su* solutions long] ?an is necess>y1 & to be> 9 m9d t any deposit =m$ by solutions conta9+ bo? silv] & ammonia may h explosive prop]ties1 especially :5 dry4 ,,*apt] ,v ,extemporis$ ,glass-,bl[+ ,app>atus--,! ,use ( ,oil or o!r ,fuels--,mak+ ,small ,rods & ,tubes f ,glass ,scrap--,! ,exam9ation ( ,manufactur$ ,app>atus ) ! ,view to ,discov]+ ! ,me?ods ,us$ 9 ,manufacture--,summ>y ( ,conditions ,necess>y = ,successful ,glass-,bl[+4 ,if1 9 ! e>ly /ages ( 8 /udy ( glass-bl[+1 ! /ud5t %\ld attempt to "w ) ! v simple/ appliances1 x is probable t 8 progress w be h9d]$2 ! use ( ! app>atus w require an undue am\nt ( c>e & 8 att5tion w be di/ract$ f ! actual manipulation ( ! glass4 ,! case is widely diff]5t aft] he has acquir$ a c]ta9 facility 9 glass-bl[+4 ,a ,simple ,=m ( ,bl[pipe4--,al?\gh !re are ev5 m simple =ms ?an t describ$ "h1 we are n conc]n$ ) !m4 ,! =m describ$ is ! simple/ ) :i* any consid]able am\nt ( glass-bl[+ c be c>ri$ out ) c]ta9ty4 ,?is =m consi/s ( a tube ?r\gh :i* air may be bl[n ) ! m\?1 a cond5sation *amb] 9 :i* any moi/ure f ! brea? c cond5se1 a bl[pipe jet1 a support+ piece & a s\rce ( flame4 ,! tube1 cond5sation *amb]1 & jet are comb9$ 9 ! ord9>y ,black's bl[pipe1 su* z is us$ = bl[pipe te/s 9 qualitative analysis2 x consi/s ( a conical t9 tube hav+ a m\?piece at ! small end & a side tube :i* c>ries a brass jet4 ,a support = su* a bl[pipe may be cut out ( a piece ( brass or t9-plate1 & %\ld be fa/5$ to a small1 flat1 wood5 bo>d4 ,a s\rce ( flame may consi/ ( an ord9>y brass elb[1 su* z is us$ on gas fitt+s1 & into :i* a piece ( ?9 brass tube 7! body ( a fi%-tail burn] f :i* ! p]=at$ non-metallic plug has be5 remov$ w s]ve q well7 has be5 fitt$4 ,x is an advantage to flatt5 ! brass tube some:at & to file ! flatt5$ end to a slope :i* corresponds ) ! angle at :i* ! bl[pipe jet ent]s ! burn]4 ,! :ole s\rce ( ! flame %\ld be m\nt$ on a sep>ate base1 9 ord] t x may be mov$ :ile adju/+ ! app>atus to ! be/ relative positions ( flame & bl[pipe jet4 ,! complete app>atus is %[n by a1 ,fig4 #af4 ,illu/ration3 ,fig4 #af ,9 ord] to take full advantage ( ?is bl[pipe1 x is desirable t ! /ud5t %\ld le>n to ma9ta9 a /eady /eam ( air ) 8 m\? &1 at ! same "t1 be able to brea!4 ,?is requires a little practice4 ,z a fir/ ex]cise 9 brea?+1 be=e try+ to brea! :ile us+ ! m\? bl[pipe1 ! /ud5t %\ld close 8 m\? & inflate 8 *eeks ) air2 n[1 /ill keep+ 8 *eeks tightly inflat$1 he %\ld attempt to brea! ?r\gh ! nose4 ,at fir/1 ?is may be f\nd r difficult1 b x becomes rem>kably easy aft] a little practice4 ,:5 he has ma/]$ ?is1 ! /ud5t may practise ! same op]ation1 b ) ! bl[pipe4 ,x is important to be> 9 m9d t ! *eeks1 n ! lungs1 =m ! res]voir = air us$ 9 ma9ta9+ ! bl[pipe flame4 ,aft] a :ile1 ! /ud5t w f9d t he c ma9ta9 a /eady air pressure & yet brea! ) complete com=t4 ,9 adju/+ ! flame1 c>e %\ld be tak5 n to bl[ s h>d z to produce a ragg$ & noisy cone ( fire4 ,a small jet1 su* z t commonly us$ on a m\? bl[pipe1 w ) c>e give a po9t$ & quiet flame1 hav+ an appe>ance simil> to t %[n 9 ! illu/ration4 ,) a bl[pipe l ?is1 x is q easy to seal glass tubes up to an in* 9 diamet]1 to jo9 tubes up to half an in* 9 diamet]1 to b5d tubes1 to bl[ small bulbs1 & to make ! simpl] =ms ( int]nal seal2 b ! provision = cond5sation ( moi/ure is n ideal1 & prolong$ use ( su* a bl[pipe also t5ds to produce undue fatigue4 ,a ,m\? ,bl[pipe ,) an ,exp&+ ,res]voir4--,?is =m ( bl[pipe c be made to give mo/ excell5t results2 x is highly portable1 & does n produce ne>ly s mu* fatigue :5 us$ cont9u\sly z ! bl[pipe describ$ 9 ! la/ section4 ,v>i\s slight modifications h be5 made 9 its con/ruction dur+ ! la/ eighty ye>s1 b t describ$ bel[ w be f\nd q satisfactory4 ,! app>atus consi/s ( a tube ?r\gh :i* air is bl[n f ! m\?1 a valve ?r\gh :i* ! air passes into an exp&+ res]voir1 & a bl[pipe jet 9 communication ) ! res]voir4 ,9 mak+ ! valve1 sev]al ess5tials h to be rememb]$2 x mu/ all[ a free passage ( air into ! res]voir1 x mu/ op5 easily1 & mu/ close quickly4 ,a satisfactory =m ( valve is t %[n by b1 ,fig4 #af4 ,! mov+ "p consi/s ( a light glass bulb ( ab\t ?ree-eights ( an in* diamet] & hav+ a glass /em ( r "u "o-eigh? diamet] & ab\t an in* & a half long4 ,?is /em re/s 9 a guide at ! end ( a brass tube1 ! bulb contact+ aga9/ ! o!r end :i* is approximately %ap$4 ,! bulb & its seat+ are gr\nd air-tight4 ,a v light spr+ holds ! bulb 9 position4 ,?is valve is fitt$ into a metal or glass ,t piece1 "o limb ( :i* leads to ! air res]voir & ! o!r limb leads to ! bl[pipe jet2 ! limb conta9+ ! valve leads to ! tube ?r\gh :i* ! air is bl[n 94 ,a conv5i5t res]voir may be made f a fairly l>ge football bladd]4 ,a network ( /r+ %\ld be fitt$ ov] ! outside ( ! bladd] & ! /r+s %\ld t]m9ate 9 a hook on :i* a weight c be hung1 9 ord] to provide a means ( adju/+ ! pressure at :i* ! air is deliv]$ to ! jet4 ,?is bladd] %\ld be wa%$ out & all[$ to dra9 aft] use4 ,! air tube :i* passes f ! valve to ! m\? may conv5i5tly be made ( brass1 b1 9 ord] to avoid ! cont9u$ contact ( metal ) ! lips ( ! op]ator1 x %\ld be fitt$ ) a non-metallic m\?piece4 ,x is an advantage f ! po9t ( view ( portability to h ! air tube easily deta*able f ! ,t piece conta9+ ! valve4 ,! bl[pipe jets1 ( :i* !re may be sev]al ) advantage1 may be made ( glass tub+1 b5t to ! mo/ conv5i5t angle & hav+ an enl>gem5t or bulb at "s po9t 9 ! tube4 ,?is bulb s]ves z a f9al cond5s+ place = any traces ( moi/ure t may escape f ! l>g] res]voir4 ,! :ole device1 bl[+ tube1 res]voir1 & ,t piece may be fa/5$ to a clamp1 s t x c be secur$ on ! edge ( any table :]e bl[pipe "w is to be c>ri$ out4 ,if ! bl[pipe is to be us$ ) gas1 ! =m ( burn] describ$ "u4 ,a ,simple ,=m ( ,bl[pipe w be f\nd q satisfactory4 ,! ,use ( ,oil1 or ,o!r ,non-,gase\s ,fuels4--,al?\gh gas1 :5 available1 is usually pref]r$ on acc\nt ( its conv5i5ce1 !re are sev]al o!r fuels :i* give a hott] flame4 ,!y h1 also1 ! additional advantage ( n requir+ any connect+ pipes2 b ea* has its own disadvantage4 ,"o liquid fuel des]ves special m5tion z be+ r less desirable ?an ! o!rs2 ?is is alcohol4 ,al?\gh v conv5i5t 9 use1 x has ! disadvantage ( be+ r too highly inflammable & capable ( burn+ )\t a wick1 ?us involv+ a c]ta9 fire risk2 ! flame is sc>cely visible 9 a bright light1 & ! heat giv5 by ei!r ! ord9>y flame or ! bl[pipe flame produc$ f alcohol is consid]ably less ?an t f a simil> flame 9 :i* coal gas is us$4 ,= small "w1 h[ev]1 ! facility ) :i* a _s lamp may be light$ may m ?an c\nt]balance ^! disadvantages at times4 ,p>aff9 ,wax4--,:]e !re is no coal gas available & ! bl[pipe is only requir$ at int]vals1 & especially :]e high portability is requir$1 !re are few fuels s conv5i5t z p>aff9 wax4 ,?is may be obta9$ 9 pieces ( a satisfactory size by cutt+ p>aff9 c&les1 f :i* ! wick has be5 )drawn1 into l5g?s ( ab\t half an in*4 ,^! cut pieces h ! advantage ov] any oily fuel1 su* z colza oil1 t !y c be wrapp$ 9 pap] or c>ri$ 9 a c>dbo>d box2 fur!r !y w keep indef9itely1 ev5 9 ! pres5ce ( air1 )\t und]go+ any p]ceptible *ange4 ,=ms ( ,lamp = ,p>aff9 ,wax4--,probably1 ! be/ =m is t devis$ by ,?omas ,bolas1 & describ$ by him 9 ! ,j\rnal ( ! ,society ( ,arts1 ,decemb] #bnd1 #ahih4 ,?is lamp consi/s ( a small op5 tray ( iron1 ?r\gh :i* pass ?ree or m flat tubes1 & betwe5 ^! tubes are plac$ small flat pieces ( wick1 ! fit be+ su* t ! pieces ( wick may be adju/$ easily by means ( a pair ( po9t$ tweez]s4 ,! flame ?us obta9$1 in/ead ( hav+ "o l>ge holl[1 is brok5 or divid$ s t ! combu/ion is conc5trat$ into a small] area1 & ! air bla/1 :i* is direct$ across ! flame1 c>ries ! flame ) x 9 a m complete mann] ?an is ! case ) ! ord9>y flame2 a m ?or\gh combu/ion be+ realis$ by ?is arrangem5t4 ,ano!r advantage is ! ease ) :i* ! wick may be *ang$ & a l>g] or small] wick ins]t$ to suit ! flame to any size ( air jet4 ,?is =m ( lamp may be us$ = oily fuel1 al?\gh x is specially suitable = p>aff9 wax4 ,two small pieces ( b5t t9-plate may be us$ z side cov]s1 & ^! s]ve to adju/ ! flame )9 c]ta9 limits4 ,a t9-plate cov] :i* fits easily ov] ! :ole lamp s]ves z an ext+ui%]4 ,! complete lamp is %[n by d1 ,fig4 #af1 & ?is figure %[s also a quick-*ange air-jet device1 ! :ole arrangem5t =m+ a bl[pipe = use :]e a non-gase\s fuel is to be employ$4 ,al?\gh ! lamp j describ$ is desirable :5 complete control ov] ! size ( ! flame is necess>y1 & if ! ideal conditions & maximum heat are to be obta9$1 yet a simpl] =m ( lamp w be f\nd to give v good results4 ,su* a lamp may consi/ ( a flat t9 tray1 hav+ a diamet] ( ab\t ?ree & a half in*es & a dep? ( ab\t "o in*4 ,9 ?is tray is a t9 support = ! wick1 & ! wick itself may consi/ ( a bundle ( s(t cotton1 = example1 a loosely roll$ piece ( cotton clo?1 b 9 ei!r case ! top ( ! wick %\ld be cut to approximately ! same angle z t at :i* ! bl[pipe jet meets ! flame4 ,9 us+ p>aff9 wax z a fuel1 x is necess>y to see t suffici5t wax rea*es ! wick to prev5t *>r+ dur+ ! fir/ few m9utes be=e ! bulk ( ! wax is melt$4 ,animal & ,vegetable ,oils4--,almo/ any oil may be us$ z a fuel1 b _m t5d to become h>d & gummy if all[$ to /& 9 ! air = any consid]able "t4 ,:5 ?is happ5s1 ! wick becomes clogg$ & x is impossible to obta9 a good flame4 ,a numb] ( ! oils t5d1 also1 to produce r /rongly smell+ smoke4 ,a ,flame-,gu>d = ,use ,) ,non-,gase\s ,fuels4--,9 ord] to avoid ! eye-/ra9 produc$ by ! lum9\s base ( ! flame f a wick burn+ p>aff9 wax or oil1 x is (t5 advantage\s to make a small tunnel ( t9-plate1 :i* c be re/$ on ! sides ( ! lamp & rises ov] ! top ( ! wick4 ,su* a flame gu>d is %[n by e1 ,fig4 #af4 ,small ,rods & ,tubes f ,glass ,scrap3--,x is sc>cely practicable to make small quantities ( good glass ) ! bl[pipe flame z ! only s\rce ( heat1 b x is less difficult to make small rods or tubes f glass scrap1 & ! ability to d ?is is sometimes ( consid]able value :5 a small tube has to be jo9$ on to "s special piece ( app>atus made ( glass ( unkn[n composition4 ,x may be possible to obta9 "s fragm5ts ( simil> glass1 ei!r f a brok5 "p ( ! app>atus or f a simil> piece1 & f ^! fragm5ts small tubes or rods c be made4 ,! fragm5ts ( glass may be melt$ toge!r on ! end ( a clay pipe-/em1 c>e be+ tak5 to avoid trapp+ air bubbles z fre% fragm5ts are add$ to ! molt5 mass4 ,:5 a suffici5t quantity ( glass has be5 accumulat$1 ! visc\s mass may be drawn out into a rod by br++ ano!r pipe-/em into contact ) ! hot mass1 rotat+ bo? pipe-/ems /eadily1 & sep>at+ !m until a rod ( ! desir$ size has be5 obta9$4 ,if1 on ! o!r h&1 x is desir$ to produce a tube f ! mass ( heat$ glass1 ! mass %\ld be bl[n holl[ be=e ! pipe-/ems support+ x are sep>at$4 ,me?ods ( ,manufacture4--,:5 ! /ud5t has famili>is$ himself ) ! m common op]ations & processes us$ 9 glass-bl[+1 he w be 9 a position to increase 8 skill & k ( special me?ods by a critical exam9ation ( v>i\s examples ( comm]cial "w4 ,!re are few ex]cises m valuable ?an su* an exam9ation1 comb9$ ) an attempt to recon/ruct ! /ages & ! me?ods by :i* ! article *os5 = exam9ation 0 made4 ,obvi\sly1 x is impossible to give full details ( all con/ructions 9 a small text-book2 b x is easy to give an example ( ! con/ructional me?ods employ$ 9 ! mak+ ( almo/ any piece ( light bl[n-glass app>atus1 & ^! me?ods %\ld prove ( special value :5 app>atus ( a new patt]n has to be evolv$ = ! purposes ( rese>*4 ,t is to say1 "o designs ! app>atus requir$1 applies kn[n me?ods ( con/ruction z f> z possible1 &1 by ! exam9ation ( comm]cial app>atus hav+ simil> features1 evolves ! new me?ods requir$4 ,= an ex]cise 9 su* a process ( recon/ruction we may well take an ord9>y comm]cial vacuum tube1 su* z t %[n by a1 ,fig4 #ag4 ,illu/ration3 ,fig4 #ag ,9 ! tube f :i* ?is draw+ 0 made1 x 0 f\nd t ! spiral 9 ! middle bulb 0 ( a slightly yell[i% col\r & gave a gre5 fluoresc5ce :5 ! electric dis*>ge 0 pass$ ?r\gh ! tube2 t is to say1 ! spiral is made ( uranium-glass1 :i* is usually a soda-glass conta9+ trace ( uranium1 & h5ce diff]+ slightly 9 composition f ! ord9>y glasses4 ,! two enclos$ tubes :i* are b5t into a s]ies ( ,s b5ds gave a p9k fluoresc5ce1 :i* indicates lead-glass2 & ! rema9d] ( ! tube fluoresc$ ) an apple-gre5 col\r2 ?is sugge/s ord9>y soda-glass4 ,we h1 !re=e1 a piece ( app>atus 9 :i* ?ree dissimil> glasses are jo9$1 :ile1 at ! same "t1 t app>atus conta9s a numb] ( int]nal seals1 & x is n probable t ! dissimil> glasses w h _! coeffici5ts ( expansion s ne>ly alike z to p]mit ( a /able int]nal seal be+ made if "o "p ( ! seal consi/s ( a glass diff]+ f t ( ! o!r "p4 ,^! consid]ations lead u to a clos] exam9ation ( ! jo9s :]e ! dissimil> glasses are introduc$1 & we f9d t 9 no case is ! int]nal seal made betwe5 dissimil> glasses1 b t a soda-glass ext5sion is jo9$ on to bo? ! uranium-glass tube & ! lead-glass tubes at a po9t ab\t half an in* be=e ! int]nal seal comm5ces4 ,c>eful exam9ation ( ^! jo9s %[s t ! *ange f "o glass to ano!r is n abrupt b gradual4 ,su* a transitional jo9t may be made by tak+ a l5g? ( soda-glass tub+1 seal+ ! end & fus+ a m9ute bead ( ! o!r glass on to ! seal$ end1 ! end is !n exp&$ & ano!r bead ( ! o!r glass add$1 ?is bead is exp&$ & ! op]ation is repeat$1 ?us build+ up a tube1 &1 f9ally1 ! tube ( ! o!r glass is jo9$ on to ! end ( ?is4 ,we are n[ conc]n$ ) ! "q ( ! ins]tion ( ! uranium-glass spiral into ! bulb 7see p4 #ch74 ,obvi\sly ! spiral is too l>ge to pass ?r\gh ! necks ( ! bulb1 & x is difficult to imag9e t ! spiral 0 obta9$ by ! ins]tion ( a l5g? ( /raight tub+ :i* 0 b5t aft] ent]+ ! bulb2 !re=e1 ! only rema9+ me?od is t ! spiral 0 made fir/ & ! soda-glass ext5sions fa/5$ on1 & t ! bulb 0 bl[n1 cut 9 halves & ! spiral ins]t$1 & ! two halves 7 !n rejo9$4 ,t ?is 0 actually ! case is confirm$ by traces ( a jo9 :i* are j visible r\nd ! middle ( ! bulb4 ,! ins]tion ( ! spiral & ! mak+ ( ! fir/ int]nal seal are %[n by b1 & c4 ,!re is "o detail 9 mak+ ! second jo9 ( ! spiral to ! bulb :i* calls = att5tion1 & ! small bran*1 simil> to an exhau/ion bran*1 at ! side ( ! bulb provides a clue to ?is4 ,if an attempt 7 made to complete ! second int]nal seal ?r\gh a clos$ bulb x w\ld be impossible to obta9 a good result1 z ! air-pressure 9 ! bulb w\ld n be "u control :5 once union 0 effect$1 & fur!r heat+ ( ! air 9 ! bulb w\ld cause expansion & p]=ate ! wall ne> ! second int]nal seal2 we !re=e make a small bran* :i* c be left op5 & ?r\gh :i* su* air-pressure z may be f\nd necess>y c be ma9ta9$4 ,! ?ird jo91 by :i* ! lead-glass tube is jo9$ to ! soda-glass is made 9 /ages simil> to ^? 9 :i* ! soda-glass & uranium-glass 7 jo9$2 b ! int]nal seal is mo/ conv5i5tly made by slid+ a l5g? ( tub+ ov] ! lead-glass & fus+ ?is tub+ to ! l>ge diamet] soda-glass tube to :i* ! lead-glass is already jo9$4 ,! fir/ /age ( ?is op]ation is illu/rat$ by d4 ,:5 ?is seal is complet$1 ! end ( ! soda-glass tube is drawn (f & seal$ z %[n 9 e1 & at ?is /age a side tube or bran* is jo9$ on4 ,! seal$ end ( ! out] & l>ge diamet] soda-glass tube is heat$ until x contracts & fuses to ! enl>gem5t t has previ\sly be5 jo9$ to ! lead-glass tube1 & ! end is bur/ out z %[n 9 f4 ,ano!r l5g? ( soda-glass is !n jo9$ on to ! bur/-out end1 & ?is l5g? ( soda-glass tub+ is drawn out to a ?9-wall$ contraction2 ! non-contract$ "p is exp&$ to =m ! bulb1 & a small exhau/ion bran* made on ! side1 ! drawn-out portion be+ cut (f1 & an electrode1 previ\sly prep>$ by coat+ a "p ( its l5g? ) a suitable enamel1 is introduc$4 ,! tube is tilt$ to keep ! electrode away f ! drawn-out end1 :i* is melt$ (f & seal$4 ,a small p]=ation is made ) a hot plat9um or iron wire 9 ! seal$ end1 ! electrode is %ak5 into position1 & ! seal+ is complet$ z expla9$ on page #db4 ,! rema9d] ( ! tube1 t is to say ! lead-glass tube & ! bulb on ! o!r side ( ! middle bulb1 is complet$ 9 a simil> mann]4 ,,summ>y ,,( ,,conditions ,,necess>y ,,= ,,success ,,9 ,,glass-,,bl[+4 ,= ! conv5i5ce ( ! /ud5t1 x may be well to summ>ise ! *ief ess5tials = success 9 glass-bl[+1 & at ! same "t to add su* brief notes on ! v>i\s me?ods z may seem desirable4 ,adju/m5t ( ,bl[pipe4--,! air jet %\ld be clean int]nally1 & s c5t]$ z to give a flame hav+ a well-def9$ blue portion1 ! tip ( ! flame %\ld n be only slightly lum9\s b purple 9 col\r4 ,9 ! case ( a bl[pipe burn+ oil or wax fuel ! flame may be a trifle m ragg$ )\t disadvantage4 ,bell[s & ,bl[+4--,! bell[s %\ld be adju/$ to deliv] air at con/ant pressure1 ei!r by ins]tion ( a tap or1 bett]1 by att5tion to ! w9d res]voir if necess>y4 ,! movem5t ( ! foot 9 bl[+ %\ld be /eady1 n j]ky4 ,heat+ ,glass4--,! tube or rod %\ld be heat$ cauti\sly until x has rea*$ its s(t5+ po9t 9 its ?icke/ "p4 ,/eady rotation ( ! glass dur+ ! heat+ is almo/ ess5tial4 ,bl[+ a ,bulb or ,exp&+ a ,jo94--,prolong$ heat+ is necess>y 9 ord] t ! ?ick p>ts may be heat$ completely ?r\gh4 ,bl[+ %\ld take place by /ages1 9 ord] t ! ?9 p>ts1 :i* t5d to exp& fir/1 h "t to cool4 ,! ?ick p>ts c !n be exp&$ by fur!r bl[+ & ?us a bulb or expansion ( ev5 ?ickness c be obta9$4 ,cutt+ ,glass4--,! mo/ useful me?od = g5]al use is by means ( ! file or glass-bl[]s' knife4 ,ei!r file or knife mu/ be kept %>p by gr9d+4 ,nei!r file nor knife %\ld be us$ on hot glass4 ,! diamond & :eel cutt] are useful = cutt+ %eet-glass1 & :5 ! diamond is employ$ a s++ noise is an indication ( a satisfactory cut4 ,lead+ a ,crack4--,a crack may be l$ 9 any desir$ direction by means ( a bead ( hot glass or a small gas flame4 ,! glass :i* x is desir$ to crack %\ld be heat$ at a po9t slightly 9 advance ( ! crack1 :i* w ext5d 9 ! direction ( ! s\rce ( ! heat4 ,turn+ ,out ! ,end ( a ,tube4--,?is is done by heat+ ! end ( ! tube & rotat+ x aga9/ an iron rod4 ,! rod mu/ be kept poli%$ & free f ru/1 & x mu/ n be all[$ to become too hot :ile 9 use1 o!rwise ! glass w /ick to x4 ,jo9+ ,unlike ,glasses4--,jo9ts betwe5 unlike glasses are (t5 un/able4 ,:5 su* jo9ts are made x is desirable to bl[ !m z ?9 z possible1 & to avoid ! junction ( unlike glasses 9 any complex jo9t1 su* z an int]nal seal4 ,a transitional portion ( tub+ may be built up by ! successive addition & int]fusion ( beads ( "o ( ! glasses to ! end ( a seal$ tube consi/+ ( ! o!r glass4 ,jo9+ a ,tube to a ,v ,?9 ,bulb4--,! bulb may be ?ick5$ at ! po9t ( union by fus+ on a bead ( glass & exp&+ ?is slightly4 ,a small c5tral portion ( ! exp&$ "p may !n be p]=at$ by bur/+ & ! tube jo9$ on4 ,ins]tion ( ,"o ,bulb ,)9 ,ano!r4--,a bulb may be divid$ into two halves by lead+ a crack r\nd x & ! inn] bulb is !n introduc$4 ,! two halves ( ! out] bulb may be fitt$ toge!r 7c>e be+ tak5 to avoid any damage to ! edges71 & ! bulb may be complet$ by rotat+ ! contact+ edges be=e ! bl[pipe until !y are s(t1 & !n exp&+ slightly by means ( air-pressure4 ,anneal+4--,= mo/ purposes1 9 ! case ( ?91 bl[pipe-made or lamp-bl[n glass app>atus1 x is suffici5t to cool sl[ly by rotat+ ! f9i%$ article ov] a smoky flame & sett+ x aside 9 a place free f draughts1 & :]e ! hot glass w n come 9 contact ) any?+4 ,simple bulbs & jo9ts d n ev5 ne$ ?is smok+2 b ?ick articles1 & especially ^? t are to be subject$ to ! /ress ( gr9d+1 ne$ m prolong$ anneal+ 9 a special ov54 ,use ( ,lead-,glass4--,:5 lead-glass is to be us$1 ! bl[pipe flame %\ld be 9 good adju/m5t & ! glass %\ld n be all[$ to approa* s ne> to ! blue cone z to be black5$4 ,slight black5+ may (t5 be remov$ by heat+ ! glass 9 ! extreme end ( ! flame4 ,lead-glass articles t5d to be r m /able ?an simil> articles ( soda-glass4 ,combu/ion-,glass4--,?is may be work$ m easily if a small p]c5tage ( oxyg5 is introduc$ into ! air ) :i* ! bl[pipe flame is produc$4 ,if ! air is replac$ entirely by oxyg5 !re is a risk ( damag+ ! bl[pipe jet1 unless a special bl[pipe is employ$4 ,int]nal ,seal4--,!re are two ways ( mak+ ^!1 "o1 9 :i* ! inn] portion ( ! tube is fus$ on to ! inside ( ! bulb or tube ?r\gh :i* x is to pass1 an op5+ is made by bur/+ & ! out] tube is jo9$ on4 ,?is is a quick & 9 "s ways m satisfactory me?od ?an ! o!r1 9 :i* !re is no sep>ate inn] piece4 ,rubb] ,bl[+ ,tube4--,9 complicat$ "w x is (t5 conv5i5t to use a ?9 rubb] bl[+-tube :i* is connect$ ) ! "w ei!r by a cork & piece ( glass tub+ or by fitt+ ov] a drawn-out end4 ,! use ( su* a bl[+-tube avoids ! inconv5i5ce ( rais+ ! "w to ! m\? :5 int]nal air-pressure is requir$4 ,"o end ( ! rubb] tube is reta9$ 9 ! m\? dur+ "w4 ,g5]al ,notes4--,a l>ge am\nt ( glass-bl[+ is spoil$ ?r\gh c>elessness 9 arrang+ ! "w be=eh&4 ,! /ud5t %\ld h e detail ( 8 manipulation cle>ly 9 m9d be=e he comm5ces ! "w2 he %\ld n tru/ to evolv+ ! me?od dur+ ! actual manipulation4 ,undue ha/e is ano!r fruitful s\rce ( failure4 ,practically e op]ation 9 glass-bl[+ c be c>ri$ out 9 a p]fectly leisurely mann]1 & x is bett] to err r on ! side ( delib]ation ?an on ! side ( ha/e4 ,if1 z w d\btless happ5 at times1 a piece ( "w gives tr\ble & x is necess>y to pause & consid] ! :ole "q1 or if = any o!r reason x is necess>y to /op dur+ ! con/ruction ( a p>tially f9i%$ jo9 or o!r op]ation1 great c>e %\ld be tak5 n to all[ ! "w to cool4 ,a l>ge1 bru%-l flame may be produc$ by increas+ ! am\nt ( gas admitt$ to ! bl[pipe1 & ! "w %\ld be held j 9 front ( ! curr5t ( hot air produc$ by su* a flame4 ,x w !n be possible to cont9ue "w on ?is )\t caus+ x to crack :5 fur!r heat is appli$4 ,z "t goes on1 ! /ud5t w f9d an increas+ confid5ce 9 8 ability to manipulate ! s(t glass1 & ) increas+ confid5ce w come rapidly increas+ p[] ( manipulation4 ,p]haps ! greate/ ob/acle to success 9 glass-bl[+ is undue ha/e 9 manipulation4 ,,index ,absorption bulbs1 #ba1 #bc4 ,airtube1 flexible1 #h1 #ajb4 ,al>m !rmomet]1 #de4 ,anneal+1 #g1 #fj4 ,bell[s1 adju/+ pressure (1 #e1 #f4 ,bell[s1 foot1 #e1 #f4 ,b5d+ tubes1 #bc4 ,black5+1 #eh1 #aja4 ,bran*+1 #ah1 #ai4 ,bru%es ( spun glass1 #ec4 ,bl[pipe flame1 quality (1 #c4 ,bl[pipe = m\? bla/1 #hj1 #hb1 #hd4 ,bl[pipe1 = p>aff9 wax1 #hb1 #hh4 ,bl[pipe1 ,h]epa?'s1 #b4 ,bl[pipe jet1 c5tr+1 #c1 #ih4 ,bl[pipe jet1 dirt 91 #c4 ,bl[pipe jet1 multiple1 #d1 #dj4 ,bl[pipe1 ,let*]'s1 *ange1 #d4 ,bl[pipe1 simple =m (1 #hj4 ,bulb1 m$ially on tube1 #bb4 ,bulbs1 #ai1 #bj1 #bb1 #ch1 #ih4 ,bulbs1 absorption1 7,liebig's71 #ba1 #bc4 ,bulbs1 divid+1 #ci1 #ie4 ,bulbs f rod1 #be4 ,bulbs1 int]nal1 #ch4 ,bulbs1 ?ick1 #ba4 ,cages1 f glass rod1 #bd1 #be1 #bg4 ,calibration1 #gb4 ,c>ius tubes1 #af4 ,cond5s]1 ,liebig's1 #cg4 ,cond5s]s1 v>i\s1 #cg1 #ch4 ,cone1 c>bon1 #h4 ,crack1 lead+1 #cj1 #ii4 ,crack+1 subv]sive1 #ajc4 ,cutt+ glass ) diamond1 #cj4 ,cutt+ tubes1 #aa1 #ii4 ,diamond 7glazi]'s71 use (1 #cj4 ,dissimil> glass1 jo9+ (1 #bb1 #id4 ,drill+1 #fa4 ,electrodes1 seal+ 91 #db1 #ig4 ,et*+ glass1 #gj4 ,extemporis$ appliances1 #hj4 ,exam9ation ( app>atus1 #ic4 ,failure1 ,ha/e *ief ,s\rce (1 #ajc4 ,failures1 ,notes z to1 #ig4 ,file1 ) oblique gr\nd edge1 #g4 ,fil+ glass1 #fc4 ,filt] pumps1 #ce ,foot1 #be ,fuels v>i\s1 #hb1 #hf1 #hg1 #hi4 ,funnel1 ?i/le1 #bc4 ,g5]al pr9ciples & precautions1 #a1 #ig ,glass1 v>ieties (1 #i1 #ee1 #ia-ig4 ,graduation1 #gb-gf ,ha/e1 ,s\rce ( ,failure1 #ajc ,heat reflector1 asbe/os1 #g4 ,heat+1 int5sive1 #g1 #eg4 ,heat+ precautions1 #ab1 #ih ,jo9+ dissimil> glass1 #bb4 ,jo9+ glass to metal1 #gf4 ,jo9+ tubes1 #af1 #id1 #ajj4 ,knife1 ,glass bl[]'s1 #g1 #ii4 ,l5ses1 gr9d+1 #fc4 ,m>k+ glass1 #fi4 ,me?ods1 analytic /udy (1 #ia1 #ic4 ,oxyg5 = int5sive heat+1 #eg1 #aja4 ,precautions & ,g5]al ,pr9ciples1 #a1 #ig4 ,pumps1 ,filt]1 #ce4 ,pumps1 ,spr5gel1 #di1 #ej4 ,re-ent]+ bran*1 #dj4 ,reflector ( heat1 asbe/os1 #g4 ,rod1 uses & articles f1 #ag1 #be1 #bg1 #bh4 ,rod1 bl[+ to holl[1 #ag1 #be1 #bf1 #ia4 ,scrap glass1 work+1 #ij4 ,seal+ tubes1 #ab1 #ac1 #ad4 ,seal$ tubes = pressure1 #ae1 #af4 ,seal+ 9 ( ,electrodes1 #db1 #ig4 ,seals1 int]nal 7airtraps71 #cb1 #ajb4 ,silv]+ glass1 #gg4 ,sold]+ glass1 #gf4 ,soxhlet-tube1 #dj4 ,spirals1 #bc1 #ie4 ,spray arre/]1 #cd4 ,spray produc]s1 #cf4 ,spr5gel pumps1 #di1 #ej4 ,sp9n+ glass1 #ea4 ,/opcocks1 #fj1 #ff4 ,/opp]+1 #fc4 ,/irr]s1 #bh1 #bi4 ,summ>y z to precautions & failures1 #ig4 ,taps1 #fj1 #ff4 ,!rmomet]s1 ,v>i\s1 #dd-di4 ,!rmo-regulator1 #bd4 ,?i/le ,funnel1 #bc4 ,tools1 ,v>i\s small1 #g4 ,turn-p9s1 #g1 #h1 #ii4 ,turn+ out op5 ends1 #ad1 #ii4 ,,pr9t$ ,,9 ,,great ,,brita9 ,,by ,w4 ,,jolly ,,sons1 ,,ltd41 ,,pr9t]s1 ,,ab]de54