,,soap-,,bubbles  ,,& ,,!  ,,=ces ,,:i* 
,,m\ld ,,!m4  ,illu/ration3 ,exp]im5t = 
%[+ by int]mitt5t light ! app>5tly      
/ation>y drops into :i* a f\nta9 is     
brok5 up by ! action ( a musical s\nd4  
7,see page #aji47     ,,soap-,,bubbles  
,,& ,,!  ,,=ces ,,:i* ,,m\ld ,,!m4      
,,be+ ,a ,,c\rse ,,( ,,?ree ,,lectures  
,,deliv]$ ,,9 ,,! ,,!atre ,,( ,,!       
,,london ,,in/itution ,,on ,,!          
,,aft]noons ,,( ,,dec4 #cj1 #ahhi1      
,,jan4 #a ,,& #c1 #ahij1 ,,be=e ,a      
,,juv5ile ,,audi5ce4  ,,by  ,c4 ,v4     
,,boys1 ,a4,r4,s4,m41 ,f4,r4,s41        
,,assi/ant ,,pr(essor ,,( ,,physics ,,at
 ,,! ,,royal ,,college ,,( ,,sci5ce1    
,,s\? ,,k5s+ton4  ,,publi%$ ,,"u ,,!    
,,direction ,,( ,,! ,,g5]al ,,lit]ature 
,,committee4  ,,society ,,= ,,promot+   
,,*ri/ian ,,k1 ,,london3 ,,nor?umb]l&   
,,av5ue1 ,w4,c42 #dc1 ,,que5 ,,victoria 
,,/reet1 ,e4,c4 ,,brighton3 #abi1 ,,nor?
 ,,/reet4 ,new ,york3 ,e4  ,j4 ,b4 ,,"y 
,,co4 #ahif4   ,,to  ,g4 ,f4 ,,rodwell1 
,,! ,,fir/  ,,sci5ce-,,ma/] ,,appo9t$   

,,at ,,m>lbor\gh ,,college1  ,?is ,book 
is ,d$icat$  ,,by ,,! ,,au?or  ,,z ,a   
,,tok5 ,,( ,,e/eem ,,& ,,gratitude1  ,,&
 ,,9 ,,! ,,hope ,,t  ,,x ,,may ,,excite 
,,9 ,a ,,few ,,"y ,,p ,,"s ,,small      
,,fraction ,,( ,,! ,,int]e/ ,,&         
,,en?usiasm ,,:i*  ,,8 ,,adv5t ,,& ,,8  
,,lectures ,,awak5$  ,,9 ,,! ,,au?or1   
,,^u ,,:om ,,! ,,light  ,,( ,,sci5ce    
,,!n ,,%one ,,=  ,,! ,,fir/ ,,"t4       
,,preface4   ,i w\ld ask ^? read]s :o h 
gr[n up1 & :o may be dispos$ to f9d     
fault ) ?is book1 on ! gr\nd t 9 s _m   
po9ts x is incomplete1 or t mu* is s    
elem5t>y or well kn[n1 to rememb] t !   
lectures 7 meant = juv5iles1 & =        
juv5iles only4 ,^! latt] ,i w\ld urge to
 d _! be/ to repeat ! exp]im5ts         
describ$4 ,!y w f9d t 9 _m cases no     
app>atus beyond a few pieces ( glass or 
india-rubb] pipe1 or o!r simple ?+s     
easily obta9$ are requir$4 ,if !y w take
 ?is tr\ble !y w f9d !mselves well      
repaid1 & if in/ead ( be+ disc\rag$ by a
 few failures !y w p]sev]e ) ! be/ means

 at _! disposal1 !y w soon f9d m to     
int]e/ !m 9 exp]im5ts 9 :i* !y only     
succe$ aft] a little tr\ble ?an 9 ^? :i*
 g all "r at once4 ,"s are s simple t no
 help c be want$1 :ile "s w probably be 
too difficult1 ev5 ) assi/ance2 b to    
enc\rage ^? :o wi% to see = !mselves !  
exp]im5ts t ,i h describ$1 ,i h giv5 su*
 h9ts at ! end ( ! book z ,i ?\ght w\ld 
be mo/ useful4  ,i h freely made use ( !
 publi%$ "w ( _m di/+ui%$ m51 among :om 
,i may m5tion ,sav>t1 ,plateau1 ,cl]k   
,maxwell1 ,sir ,william ,?omson1 ,"l    
,rayleigh1 ,mr4 ,*i*e/] ,bell1 & ,pr(4  
,ruck]4 ,! exp]im5ts h mo/ly be5        
describ$ by !m1 "s h be5 tak5 f j\rnals1
 & ,i h devis$ or arrang$ a few4 ,i am  
also indebt$ to ,pr(4 ,ruck] = ! use (  
v>i\s pieces ( app>atus :i* _h be5      
prep>$ = 8 lectures4                    
,,soap-,,bubbles1 ,,& ,,! ,,=ces ,,:i*  
,,m\ld ,,!m4   ,i d n suppose t !re is  
any "o 9 ?is room :o has n occasionally 
bl[n a common soap-bubble1 & :ile admir+
 ! p]fection ( its =m1 & ! m>vell\s     

brilliancy ( its col\rs1 wond]$ h[ x is 
t su* a magnific5t object c be s easily 
produc$4  ,i hope t none ( y are yet    
tir$ ( play+ ) bubbles1 because1 z ,i   
hope we %all see dur+ ! week1 !re is m 9
 a common bubble ?an ^? :o h only play$ 
) !m g5]ally imag9e4  ,! wond] &        
admiration s beautifully portray$ by    
,millais 9 a picture1 copies ( :i*1     
?anks to mod]n adv]tis+ ent]prise1 "s ( 
y may possibly h se51 w1 ,i hope1 9 no  
way fall away 9 consequ5ce ( ^!         
lectures2 ,i ?9k y w f9d t x w gr[ z y\r
 k ( ! subject increases4 ,y may be     
int]e/$ to he> t we are n ! only        
juv5iles :o h play$ ) bubbles4 ,ages ago
 *ildr5 did ! same1 & ?\gh no m5tion (  
?is is made by any ( ! classical au?ors1
 we "k t !y did1 because !re is an      
,etruscan vase 9 ! ,l\vre 9 ,p>is ( !   
greate/ antiquity1 on :i* *ildr5 are    
repres5t$ bl[+ bubbles ) a pipe4 ,!re is
 h[ev]1 no means ( tell+ n[ ^: soap !y  
us$4  ,x is possible t "s ( y may l to  
"k :y ,i h *os5 soap-bubbles z my       

subject2 if s1 ,i am glad to tell y4    
,?\gh !re are _m subjects :i* might seem
 to a beg9n] to be m wond]ful1 m        
brilliant1 or m excit+1 !re are few :i* 
s directly be> ^u ! ?+s :i* we see e    
day4 ,y _c p\r wat] f a jug or tea f a  
tea-pot2 y _c ev5 d any?+ ) a liquid (  
any k9d1 )\t sett+ 9 action ! =ces to   
:i* ,i am ab\t to direct y\r att5tion4  
,y _c !n fail to be frequ5tly rem9d$ (  
:at y w he> & see 9 ?is room1 &1 :at is 
p]haps mo/ important ( all1 _m ( ! ?+s  
,i am go+ to %[ y are s simple t y w be 
able )\t any app>atus to repeat =       
y\rselves ! exp]im5ts :i* ,i h prep>$1 &
 ?is y w f9d m int]e/+ & in/ructive ?an 
m]ely li/5+ to me & wat*+ :at ,i d4     
,!re is "o m ?+ ,i %\ld l to expla91 & t
 is :y ,i am go+ to %[ exp]im5ts at all4
 ,y w at once answ] because x w\ld be s 
dreadfully dull if ,i didn't4 ,p]haps x 
w\ld4 ,b t is n ! only reason4 ,i w\ld  
rem9d y !n t :5 we want to f9d out any?+
 t we d n "k1 !re are two ways (        
proce$+4 ,we may ei!r ask somebody else 

:o does "k1 or read :at ! mo/ le>n$ m5 h
 writt5 ab\t x1 :i* is a v good plan if 
anybody happ5s to be able to answ] our  
"q2 or else we may adopt ! o!r plan1 &  
by arrang+ an exp]im5t1 try = ourselves4
 ,an exp]im5t is a "q :i* we ask (      
,nature1 :o is always ready to give a   
correct answ]1 provid$ we ask prop]ly1 t
 is1 provid$ we arrange a prop]         
exp]im5t4 ,an exp]im5t is n a conjur+   
trick1 some?+ simply to make y wond]1   
nor is x simply %[n because x is        
beautiful1 or because x s]ves to relieve
 ! monotony ( a lecture2 if any ( !     
exp]im5ts ,i %[ are beautiful1 or d s]ve
 to make ^! lectures a little less dull1
 s mu* ! bett]2 b _! *ief object is to  
enable y to see = y\rselves :at ! true  
answ]s are to que/ions t ,i %all ask4   
,illu/ration3 ,fig4 #a4  ,n[ ,i %all    
beg9 by p]=m+ an exp]im5t :i* y h all   
probably tri$ doz5s ( times4 ,i h 9 my  
h& a common camel's-hair bru%4 ,if y    
want to make ! hairs cl+ toge!r & come  
to a po9t1 y wet x1 & !n y say ! hairs  

cl+ toge!r because ! bru% is wet4 ,n[   
let u try ! exp]im5t2 b z y _c see ?is  
bru% across ! room1 ,i hold x 9 front ( 
! lant]n1 & y c see x enl>g$ ^u ! scre5 
7,fig4 #a1 left h&74 ,n[ x is dry1 & !  
hairs are sep>ately visible4 ,i am n[   
dipp+ x 9 ! wat]1 z y c see1 & on tak+ x
 out1 ! hairs1 z we expect$1 cl+ toge!r 
7,fig4 #a1 "r h&71 because !y are wet1 z
 we are 9 ! habit ( say+4 ,i %all n[    
hold ! bru% 9 ! wat]1 b !re x is evid5t 
t ! hairs d n cl+ at all 7,fig4 #a1     
middle71 & yet !y surely are wet n[1 be+
 actually 9 ! wat]4 ,x w\ld appe> !n t !
 reason :i* we always give is n exactly 
correct4 ,?is exp]im5t1 :i* requires    
no?+ m ?an a bru% & a glass ( wat]1 !n  
%[s t ! hairs ( a bru% cl+ toge!r n only
 because !y are wet1 b = "s o!r reason z
 well :i* we d n yet "k4 ,x also %[s t a
 v common belief z to op5+ our eyes "u  
wat] is n f\nd$ on fact4 ,x is v        
commonly said t if y dive into ! wat] ) 
y\r eyes %ut y _c see prop]ly :5 y op5  
!m "u wat]1 because ! wat] gums !       

eyela%es d[n ov] ! eyes2 & !re=e y mu/  
dive 9 ) y\r eyes op5 if y wi% to see "u
 wat]4 ,n[ z a matt] ( fact ?is is n !  
case at all2 x makes no diff]5ce :e!r   
y\r eyes are op5 or n :5 y dive 91 y c  
op5 !m & see j z well ei!r way4 ,9 !    
case ( ! bru% we h se5 t wat] does n    
cause ! hairs to cl+ toge!r or to any?+ 
else :5 "u ! wat]1 x is only :5 tak5 out
 t ?is is ! case4 ,?is exp]im5t1 ?\gh x 
has n expla9$ :y ! hairs cl+ toge!r1 has
 at any rate told u t ! reason always   
giv5 is n suffici5t4  ,i %all n[ try    
ano!r exp]im5t z simple z ! la/4 ,i h a 
pipe f :i* wat] is v sl[ly issu+1 b x   
does n fall away cont9u\sly2 a drop =ms 
:i* sl[ly gr[s until x has atta9$ a     
c]ta9 def9ite size1 & !n x sudd5ly falls
 away4 ,i want y to notice t e "t ?is   
happ5s ! drop is always exactly ! same  
size & %ape4 ,n[ ?is _c be m]e *ance2   
!re mu/ be "s reason = ! def9ite size1 &
 %ape4 ,:y does ! wat] rema9 at all8 ,x 
is heavy & is ready to fall1 b x does n 
fall2 x rema9s cl++ until x is a c]ta9  

size1 & !n x sudd5ly breaks away1 z if  
:atev] held x 0 n /rong en\gh to c>ry a 
great] weight4 ,mr4 ,wor?+ton has       
c>efully drawn on a magnifi$ scale !    
exact %ape ( a drop ( wat] ( diff]5t    
sizes1 & ^! y n[ see ^u ! diagram on !  
wall 7,fig4 #b74 ,^! diagrams w probably
 sugge/ ! idea t ! wat] is hang+ susp5d$
 9 an ela/ic bag1 & t ! bag breaks or is
 torn away :5 !re is too great a weight 
= x to c>ry4 ,x is true !re is no bag at
 all really1 b yet ! drops take a %ape  
:i* sugge/s an ela/ic bag4 ,to %[ y t   
?is is no fancy1 ,i h support$ by a     
tripod a l>ge r+ ( wood ov] :i* a ?9    
%eet ( india-rubb] has be5 /ret*$1 & n[ 
on all[+ wat] to p\r 9 f ?is pipe y w   
see ! rubb] sl[ly /ret*+ "u ! increas+  
weight1 &1 :at ,i especially want y to  
notice1 x always assumes a =m l ^? on ! 
diagram4 ,z ! weight ( wat] increases ! 
bag /ret*es1 & n[ t !re is ab\t a       
pailful ( wat] 9 x1 x is gett+ to a /ate
 :i* indicates t x _c la/ mu* long]2 x  
is l ! wat]-drop j be=e x falls away1 & 

n[ sudd5ly x *anges its %ape 7,fig4 #c71
 & x w\ld imm$iately te> itself away if 
x 7 n = ! fact t india-rubb] does n     
/ret* indef9itely2 aft] a "t x gets     
tight & w )/& a great] pull )\t giv+    
way4 ,y !re=e see ! great drop n[       
p]man5tly hang+ :i* is almo/ exactly !  
same 9 %ape z ! wat]-drop at ! po9t (   
rupture4 ,i %all n[ let ! wat] run out  
by means ( a syphon1 & !n ! drop sl[ly  
contracts aga94 ,n[ 9 ?is case we cle>ly
 h a heavy liquid 9 an ela/ic bag1 :]eas
 9 ! drop ( wat] we h ! same liquid b no
 bag t is visible4 ,z ! two drops behave
 9 almo/ exactly ! same way1 we %\ld    
naturally be l$ to expect t _! =m &     
movem5ts are due to ! same cause1 & t ! 
small wat]-drop has some?+ hold+ x      
toge!r l ! india-rubb] y n[ see4        
,illu/ration3 ,fig4 #b4  ,illu/ration3  
,fig4 #c4  ,let u see h[ ?is fits ! fir/
 exp]im5t ) ! bru%4 ,t %[$ t ! hairs d n
 cl+ toge!r simply because !y are wet2 x
 is necess>y also t ! bru% %\ld be tak5 
out ( ! wat]1 or 9 o!r words x is       

necess>y t ! surface or ! sk9 ( ! wat]  
%\ld be pres5t to b9d ! hairs toge!r4   
,if !n we suppose t ! surface ( wat] is 
l an ela/ic sk91 !n bo? ! exp]im5ts ) ! 
wet bru% & ) ! wat]-drop w be expla9$4  
,let u !re=e try ano!r exp]im5t to see  
:e!r 9 o!r ways wat] behaves z if x _h  
an ela/ic sk94  ,i h "h a pla9 wire     
frame fix$ to a /em ) a weight at !     
bottom1 & a holl[ glass globe fa/5$ to x
 ) seal+-wax4 ,! globe is l>ge en\gh to 
make ! :ole ?+ float 9 wat] ) ! frame up
 9 ! air4 ,i c ( c\rse press x d[n s t !
 frame t\*es ! wat]4 ,to make ! movem5t 
( ! frame m evid5t !re is fix$ to x a   
pap] flag4  ,n[ if wat] behaves z if !  
surface 7 an ela/ic sk91 !n x %\ld resi/
 ! upw>d passage ( ! frame :i* ,i am n[ 
hold+ bel[ ! surface4 ,i let g1 & in/ead
 ( bobb+ up z x w\ld d if !re 7 no su*  
action1 x rema9s te!r$ d[n by ?is sk9 ( 
! wat]4 ,if ,i di/urb ! wat] s z to let 
! frame out at "o corn]1 !n1 z y see1 x 
dances up imm$iately 7,fig4 #d74 ,y c   
see t ! sk9 ( ! wat] mu/ h be5 fairly   

/rong1 because a weight ( ab\t "o qu>t] 
( an ounce plac$ ^u ! frame is only j   
suffici5t to make ! :ole ?+ s9k4  ,?is  
app>atus :i* 0 orig9ally describ$ by    
,van d] ,m5sbrugghe ,i %all make use (  
aga9 9 a few m9utes4  ,illu/ration3     
,fig4 #d4  ,i c %[ y 9 a m /rik+ way t  
!re is ?is ela/ic lay] or sk9 on pure   
clean wat]4 ,i h a small sieve made (   
wire gauze suffici5tly co>se to all[ a  
common p9 to be put ?r\gh any ( ! holes4
 ,!re are moreov] ab\t elev5 ?\s& ( ^!  
holes 9 ! bottom ( ! sieve4 ,n[1 z y "k1
 clean wire is wett$ by wat]1 t is1 if x
 is dipp$ 9 wat] x comes out wet2 on !  
o!r h&1 "s mat]ials1 su* z p>aff9 wax1 (
 :i* p>aff9 c&les are made1 are n wett$ 
or really t\*$ by wat]1 z y may see =   
y\rselves if y w only dip a p>aff9 c&le 
into wat]4 ,i h melt$ a quantity (      
p>aff9 9 a di% & dipp$ ?is gauze into ! 
melt$ p>aff9 s z to coat ! wire all ov] 
) x1 b ,i h %ak5 x well :ile hot to     
knock ! p>aff9 out ( ! holes4 ,y c n[   
see on ! scre5 t ! holes1 all except "o 

or two1 are op51 & t a common p9 c be   
pass$ ?r\gh readily en\gh4 ,?is !n is ! 
app>atus4 ,n[ if wat] has an ela/ic sk9 
:i* x requires =ce to /ret*1 x ought n  
to run ?r\gh ^! holes v readily2 x ought
 n to be able to get ?r\gh at all unless
 =c$1 because at ea* hole ! sk9 w\ld h  
to be /ret*$ to all[ ! wat] to get to ! 
o!r side4 ,?is y und]/& is only true if 
! wat] does n wet or really t\* ! wire4 
,n[ to prev5t ! wat] t ,i am go+ to p\r 
9 f /rik+ ! bottom ) s mu* =ce z to     
drive x ?r\gh1 ,i h laid a small piece (
 pap] 9 ! sieve1 & am p\r+ ! wat] on to 
! pap]1 :i* breaks ! fall 7,fig4 #e74 ,i
 h n[ p\r$ 9 ab\t half a tumbl] ( wat]1 
& ,i might put 9 m4 ,i take away ! pap] 
b n a drop runs ?r\gh4 ,if ,i give !    
sieve a jolt !n ! wat] is driv5 to ! o!r
 side1 & 9 a mom5t x has all escap$4    
,p]haps ?is w rem9d y ( "o ( ! exploits 
( our old fri5d ,simple ,simon1      ,:o
 w5t = wat] 9 a sieve1     ,b soon x all
 ran ?r\gh4  ,b y see if y only manage !
 sieve prop]ly1 ?is is n q s absurd z p 

g5]ally suppose4  ,illu/ration3 ,fig4   
#e4  ,if n[ ,i %ake ! wat] (f ! sieve1  
,i c1 = ! same reason1 set x to float on
 wat]1 because its weight is n suffici5t
 to /ret* ! sk9 ( ! wat] ?r\gh all !    
holes4 ,! wat]1 !re=e1 rema9s on ! o!r  
side1 & x floats ev5 ?\gh1 z ,i h       
already said1 !re are elev5 ?\s& holes 9
 ! bottom1 any "o ( :i* is l>ge en\gh to
 all[ an ord9>y p9 to pass ?r\gh4 ,?is  
exp]im5t also illu/rates h[ difficult x 
is to write real & p]fect nons5se4  ,y  
may rememb] "o ( ! /ories 9 ,le>'s book 
( ,nons5se ,songs4      ,!y w5t to sea 9
 a sieve1 !y did1       ,9 a sieve !y   
w5t to sea3     ,9 spite ( all _! fri5ds
 c\ld say1     ,on a w9t]'s morn1 on a  
/ormy day1       ,9 a sieve !y w5t to   
sea4                99    99    99      
,!y sail$ away 9 a sieve1 !y did1       
,9 a sieve !y sail$ s fa/1     ,) only a
 beautiful pea-gre5 veil1     ,ti$ ) a  
rib& by way ( a sail1       ,to a small 
tobacco-pipe ma/2  ,& s on4 ,y see t x  
is q possible to g to sea 9 a sieve--t  

is1 if ! sieve is l>ge en\gh & ! wat] is
 n too r\gh--& t ! above l9es are n[    
realiz$ 9 e p>ticul> 7,fig4 #f74        
,illu/ration3 ,fig4 #f4  ,i may give "o 
m example ( ! p[] ( ?is ela/ic sk9 (    
wat]4 ,if y wi% to p\r wat] f a tumbl]  
into a n>r[-neck$ bottle1 y "k h[ if y  
p\r sl[ly x ne>ly all runs d[n ! side ( 
! glass & gets spill$ ab\t1 :]eas if y  
p\r quickly !re is no room = ! great    
quantity ( wat] to pass into ! bottle   
all at once1 & s x gets spill$ aga94 ,b 
if y take a piece ( /ick or a glass rod1
 & hold x aga9/ ! edge ( ! tumbl]1 !n ! 
wat] runs d[n ! rod & into ! bottle1 &  
none is lo/ 7,fig4 #g72 y may ev5 hold !
 rod incl9$ to "o side1 z ,i am n[ do+1 
b ! wat] runs d[n ! wet rod because ?is 
ela/ic sk9 =ms a k9d ( tube :i* prev5ts 
! wat] f escap+4 ,?is action is (t5 made
 use ( 9 ! c\ntry to c>ry ! wat] f !    
gutt]s "u ! ro( into a wat]-butt bel[4  
,a piece ( /ick does ne>ly z well z an  
iron pipe1 & x does n co/ any?+ l s mu*4
  ,illu/ration3 ,fig4 #g4  ,i ?9k !n ,i 

h n[ done en\gh to %[ t on ! surface (  
wat] !re is a k9d ( ela/ic sk94 ,i d n  
mean t !re is any?+ t is n wat] on !    
surface1 b t ! wat] :ile !re acts 9 a   
diff]5t way to :at x does inside1 & t x 
acts z if x 7 an ela/ic sk9 made (      
some?+ l v ?9 india-rubb]1 only t x is  
p]fectly & absolutely ela/ic1 :i*       
india-rubb] is n4  ,y w n[ be 9 a       
position to und]/& h[ x is t 9 n>r[     
tubes wat] does n f9d its own level1 b  
behaves 9 an unexpect$ mann]4 ,i h plac$
 9 front ( ! lant]n a di% ( wat] col\r$ 
blue s t y may ! m easily see x4 ,i %all
 n[ dip into ! wat] a v n>r[ glass pipe1
 & imm$iately ! wat] ru%es up & /&s ab\t
 half an in* above ! g5]al level4 ,!    
tube inside is wet4 ,! ela/ic sk9 ( !   
wat] is !re=e atta*$ to ! tube1 & goes  
on pull+ up ! wat] until ! weight ( !   
wat] rais$ above ! g5]al level is equal 
to ! =ce ex]t$ by ! sk94 ,if ,i take a  
tube ab\t twice z big1 !n ?is pull+     
action :i* is go+ on all r\nd ! tube w  
cause x to lift twice ! weight ( wat]1 b

 ?is w n make ! wat] rise twice z high1 
because ! l>g] tube holds s mu* m wat] =
 a giv5 l5g? ?an ! small] tube4 ,x w n  
ev5 pull x up z high z x did 9 ! case ( 
! small] tube1 because if x 7 pull$ up z
 high ! weight ( ! wat] rais$ w\ld 9 t  
case be f\r times z great1 & n only     
twice z great1 z y might at fir/ ?9k4 ,x
 w !re=e only raise ! wat] 9 ! l>g] tube
 to half ! height1 & n[ t ! two tubes   
are side by side y see ! wat] 9 ! small]
 tube /&+ twice z high z x does 9 ! l>g]
 tube4 ,9 ! same way1 if ,i 7 to take a 
tube z f9e z a hair ! wat] w\ld g up ev]
 s mu* high]4 ,x is = ?is reason t ?is  
is call$ ,capill>ity1 f ! ,lat9 ^w      
capillus1 a hair1 because ! action is s 
m>k$ 9 a tube ! size ( a hair4          
,illu/ration3 ,fig4 #h4  ,suppos+ n[ y  
_h a great numb] ( tubes ( all sizes1 & 
plac$ !m 9 a r[ ) ! smalle/ on "o side &
 all ! o!rs 9 ! ord] ( _! sizes1 !n x is
 evid5t t ! wat] w\ld rise highe/ 9 !   
smalle/ tube & less & less high 9 ea*   
tube 9 ! r[ 7,fig4 #h71 until :5 y came 

to a v l>ge tube y w\ld n be able to see
 t ! wat] 0 rais$ at all4 ,y c v easily 
obta9 ! same k9d ( effect by simply tak+
 two squ>e pieces ( w9d[ glass & plac+  
!m face to face ) a common mat* or small
 fragm5t ( any?+ to keep !m a small     
di/ance ap>t along "o edge :ile !y meet 
toge!r along ! opposite edge4 ,an       
india-rubb] r+ /ret*$ ov] !m w hold !m 9
 ?is position4 ,i n[ take ?is pair (    
plates & /& x 9 a di% ( col\r$ wat]1 & y
 at once see t ! wat] creeps up to ! top
 ( ! plates on ! edge :]e !y meet1 & z !
 di/ance betwe5 ! plates gradually      
increases1 s ! height to :i* ! wat]     
rises gradually gets less1 & ! result is
 t ! surface ( ! liquid =ms a           
beautifully regul> curve :i* is call$ by
 ma!maticians a rectangul> hyp]bola     
7,fig4 #i74 ,i %all h pres5tly to say m 
ab\t ?is & "s o!r curves1 & s ,i %all n 
d m n[ ?an /ate t ! hyp]bola is =m$     
because z ! wid? betwe5 ! plates gets   
great] ! height gets less1 or1 :at comes
 to ! same ?+1 because ! weight ( liquid

 pull$ up at any small "p ( ! curve is  
always ! same4  ,illu/ration3 ,fig4 #i4 
,if ! plates or ! tubes _h be5 made (   
mat]ial n wett$ by wat]1 !n ! effect ( !
 t5sion ( ! surface w\ld be to drag !   
liquid away f ! n>r[ spaces1 & ! m s z !
 spaces 7 n>r[]4 ,z x is n easy to %[   
?is well ) p>aff9$ glass plates or tubes
 & wat]1 ,i %all use ano!r liquid :i*   
does n wet or t\* clean glass1 namely1  
quicksilv]4 ,z x is n possible to see   
?r\gh quicksilv]1 x w n d to put a n>r[ 
tube into ?is liquid to %[ t ! level is 
l[] 9 ! tube ?an 9 ! surr\nd+ vessel1 b 
! same result may be obta9$ by hav+ a   
wide & a n>r[ tube jo9$ toge!r4 ,!n1 z y
 see ^u ! scre51 ! quicksilv] is l[] 9 !
 n>r[ ?an 9 ! wide tube1 :]eas 9 a      
simil> app>atus ! rev]se is ! case )    
wat] 7,fig4 #aj74  ,illu/ration3 ,fig4  
#aj4  ,i want y n[ to consid] :at is    
happ5+ :5 two flat plates p>tly imm]s$ 9
 wat] are held close toge!r4 ,we h se5 t
 ! wat] rises betwe5 !m4 ,^? p>ts ( ^!  
two plates1 :i* h air betwe5 !m & also  

air outside !m 7indicat$ by ! lett] a 9 
,fig4 #aa71 are ea* ( !m press$ equally 
9 opposite directions by ! pressure ( ! 
air1 & s ^! p>ts d n t5d to approa* or  
to rec$e f "o ano!r4 ,^! p>ts aga9 :i* h
 wat] on ea* side ( ea* ( !m 7z indicat$
 by ! lett] c7 are equally press$ 9     
opposite directions by ! pressure ( !   
wat]1 & s ^! p>ts d n t5d to approa* or 
to rec$e f "o ano!r4 ,b ^? p>ts ( !     
plates 7b7 :i* h wat] betwe5 !m & air   
outside w\ld1 y might ?9k1 be pu%$ ap>t 
by ! wat] betwe5 !m ) a great] =ce ?an t
 :i* c\ld be ex]t$ by ! air outside1 & s
 y might be l$ to expect t on ?is acc\nt
 a pair ( plates if free to move w\ld   
sep>ate at once4 ,b su* an idea ?\gh v  
natural is wrong1 & = ?is reason4 ,!    
wat] t is rais$ betwe5 ! plates be+     
above ! g5]al level mu/ be "u a less    
pressure1 because1 z e "o kn[s1 z y g   
d[n 9 wat] ! pressure increases1 & s z y
 g up ! pressure mu/ get less4 ,! wat]  
!n t is rais$ betwe5 ! plates is "u a   
less pressure ?an ! air outside1 & s on 

! :ole ! plates are pu%$ toge!r4 ,y c   
easily see t ?is is ! case4 ,i h two v  
light holl[ glass beads su* z are us$ to
 decorate a ,*ri/mas tree4 ,^! w float 9
 wat] if "o end is /opp$ ) seal+-wax4   
,^! are bo? wett$ by wat]1 & s ! wat]   
betwe5 !m is slightly rais$1 = !y act 9 
! same way z ! two plates1 b n s        
p[]fully4 ,h[ev]1 y w h no difficulty 9 
see+ t ! mom5t ,i leave !m alone !y ru% 
toge!r ) consid]able =ce4 ,n[ if y ref] 
to ! second figure 9 ! diagram1 :i*     
repres5ts two plates :i* are nei!r ( !m 
wett$1 ,i ?9k y w see1 )\t any          
explanation f me1 t !y %\ld be press$   
toge!r1 & ?is is made evid5t by         
exp]im5t4 ,two o!r beads :i* h be5 dipp$
 9 p>aff9 wax s t !y are nei!r ( !m     
wett$ by wat] float up to "o ano!r aga9 
:5 sep>at$ z ?\gh !y attract$ ea* o!r j 
z ! clean glass beads did4              
,illu/ration3 ,fig4 #aa4  ,if y aga9    
consid] ^! two cases1 y w see t a plate 
t is wett$ t5ds to move t[>ds ! high]   
level ( ! liquid1 :]eas "o t is n wett$ 

t5ds to move t[>ds ! l[] level1 t is if 
! level ( ! liquid on ! two sides is    
made diff]5t by capill>y action4 ,n[    
suppose "o plate wett$ & ! o!r n wett$1 
!n1 z ! diagram imp]fectly %[s1 ! level 
( ! liquid betwe5 ! plates :]e x meets !
 non-wett$ plate is high] ?an t outside1
 :ile :]e x meets ! wett$ plate x is l[]
 ?an t outside2 s ea* plate t5ds to g   
away f ! o!r1 z y c see n[ t ,i h "o    
p>aff9$ & "o clean ball float+ 9 ! same 
wat]4 ,!y appe> to repel "o ano!r4  ,y  
may also notice t ! surface ( ! liquid  
ne> a wett$ plate is curv$1 ) ! holl[ ( 
! curve upw>ds1 :ile ne> a non-wett$    
plate ! rev]se is ! case4 ,t ?is        
curvature ( ! surface is ( ! fir/       
importance ,i c %[ y by a v simple      
exp]im5t1 :i* y c repeat at home z      
easily z ! la/ t ,i h %[n4 ,i h a clean 
glass bead float+ 9 wat] 9 a clean glass
 vessel1 :i* is n q full4 ,! bead always
 goes to ! side ( ! vessel4 ,x is       
impossible to make x rema9 9 ! middle1 x
 always gets to "o side or ! o!r        

directly4 ,i %all n[ gradually add wat] 
until ! level ( ! wat] is r high] ?an t 
( ! edge ( ! vessel4 ,! surface is !n   
r\nd$ ne> ! vessel1 :ile x is holl[ ne> 
! bead1 & n[ ! bead sails away t[>ds !  
c5tre1 & c by no possibility be made to 
/op ne> ei!r side4 ,) a p>aff9$ bead !  
rev]se is ! case1 z y w\ld expect4      
,in/ead ( a p>aff9$ bead y may use a    
common ne$le1 :i* y w f9d w float on    
wat] 9 a tumbl]1 if plac$ ^u x v g5tly4 
,if ! tumbl] is n q full ! ne$le w      
always g away f ! edge1 b if r ov]-fill$
 x w "w up to "o side1 & !n possibly    
roll ov] ! edge2 any bubbles1 on ! o!r  
h&1 :i* 7 adh]+ to ! glass be=e w1 !    
in/ant t ! wat] is above ! edge ( !     
glass1 %oot away f ! edge 9 ! mo/ sudd5 
& surpris+ mann]4 ,?is sudd5 *ange c be 
mo/ easily se5 by ne>ly fill+ ! glass ) 
wat]1 & !n gradually dipp+ 9 & tak+ out 
a cork1 :i* w cause ! level to sl[ly    
*ange4  ,s f> ,i h giv5 y no idea :at   
=ce is ex]t$ by ?is ela/ic sk9 ( wat]4  
,measurem5ts made ) n>r[ tubes1 ) drops1

 & 9 o!r ways1 all %[ t x is almo/      
exactly equal to ! weight ( ?ree & a    
qu>t] gra9s to ! in*4 ,we h1 moreov]1 n 
yet se5 :e!r o!r liquids act 9 ! same   
way1 & if s :e!r 9 o!r cases ! /r5g? ( !
 ela/ic sk9 is ! same4  ,y n[ see a     
second tube id5tical ) t f :i* drops (  
wat] 7 =m$1 b 9 ?is case ! liquid is    
alcohol4 ,n[ t drops are =m+1 y see at  
once t :ile alcohol makes drops :i* h a 
def9ite size & %ape :5 !y fall away1 !  
alcohol drops are n by any means s l>ge 
z ! drops ( wat] :i* are fall+ by _!    
side4 ,two possible reasons might be    
giv5 to expla9 ?is4 ,ei!r alcohol is a  
heavi] liquid ?an wat]1 :i* w\ld acc\nt 
= ! small] drop if ! sk9 9 ea* liquid _h
 ! same /r5g?1 or else if alcohol is n  
heavi] ?an wat] its sk9 mu/ be weak] ?an
 ! sk9 ( wat]4 ,z a matt] ( fact alcohol
 is a light] liquid ?an wat]1 & s /ill m
 mu/ ! sk9 ( alcohol be weak] ?an t (   
wat]4  ,illu/ration3 ,fig4 #ab4  ,we c  
easily put ?is to ! te/ ( exp]im5t4 ,9 !
 game t is call$ ! tug-(-w> y "k well   

en\gh :i* side is ! /ronge/2 x is ! side
 :i* pulls ! o!r ov] ! l9e4 ,let u !n   
make alcohol & wat] play ! same game4 ,9
 ord] t y may see ! wat]1 x is col\r$   
blue4 ,x is ly+ z a %all[ lay] on !     
bottom ( ?is :ite di%4 ,at ! pres5t "t !
 sk9 ( ! wat] is pull+ equally 9 all    
directions1 & s no?+ happ5s2 b if ,i p\r
 a few drops ( alcohol into ! middle1 !n
 at ! l9e :i* sep>ates ! alcohol f !    
wat] we h alcohol on "o side pull+ 91   
:ile we h wat] on ! o!r side pull+ out1 
& y see ! result4 ,! wat] is victori\s2 
x ru%es away 9 all directions1 c>ry+ a  
quantity ( ! alcohol away ) x1 & leaves 
! bottom ( ! di% dry 7,fig4 #ac74       
,illu/ration3 ,fig4 #ac4  ,?is diff]5ce 
9 ! /r5g? ( ! sk9 ( alcohol & ( wat]1 or
 ( wat] conta9+ mu* or little alcohol1  
gives rise to a curi\s motion :i* y may 
see on ! side ( a w9e-glass 9 :i* !re is
 "s fairly /rong w9e1 su* z port4 ,!    
liquid is obs]v$ to climb up ! sides ( !
 glass1 !n to ga!r into drops1 & to run 
d[n aga91 & ?is goes on = a long "t4    

,?is is expla9$ z foll[s3--,! ?9 lay] ( 
w9e on ! side ( ! glass be+ expos$ to ! 
air1 loses its alcohol by evaporation m 
quickly ?an ! w9e 9 ! glass4 ,x !re=e   
becomes weak] 9 alcohol or /rong] 9 wat]
 ?an t bel[1 & = ?is reason x has a     
/rong] sk94 ,x !re=e pulls up m w9e f   
bel[1 & ?is goes on until !re is s mu* t
 drops =m1 & x runs back aga9 into !    
glass1 z y n[ see ^u ! scre5 7,fig4     
#ad74 ,!re c be no d\bt t ?is movem5t is
 ref]r$ to 9 ,prov]bs xxiii4 #ca3 ,look 
n ?\ ^u ! w9e :5 x is r$1 :5 x give? 8  
col\r 9 ! cup1 :5 x move? itself aright4
  ,if y rememb] t ?is movem5t only      
occurs ) /rong w9e1 & t x mu/ h be5 kn[n
 to e "o at ! "t t ^! words 7 writt51 & 
us$ z a te/ ( ! /r5g? ( w9e1 because 9  
^? days e "o drank w9e1 !n y w agree t  
?is explanation ( ! mean+ ( t v]se is ! 
"r "o4 ,i w\ld ask y also to consid]    
:e!r x is n probable t o!r passages :i* 
d n n[ seem to convey to u any mean+    
:atev]1 may n 9 ! same way h ref]r$ to !
 common k & cu/oms ( ! day1 ( :i* at !  

pres5t "t we happ5 to be ignorant4      
,illu/ration3 ,fig4 #ad4  ,e!r1 9 ! same
 way1 has a sk9 :i* is weak] ?an ! sk9 (
 wat]4 ,! v smalle/ quantity ( e!r on ! 
surface ( wat] w produce a p]ceptible   
effect4 ,= in/ance1 ! wire frame :i* ,i 
left "s "t ago is /ill re/+ aga9/ !     
wat]-sk94 ,! buoyancy ( ! glass bulb is 
try+ to pu% x ?r\gh1 b ! upw>d =ce is j 
n suffici5t4 ,i w h[ev] p\r a few drops 
( e!r into a glass1 & simply p\r ! vap\r
 ^u ! surface ( ! wat] 7n a drop (      
liquid is pass+ ov]71 & almo/ imm$iately
 suffici5t e!r has cond5s$ ^u ! wat] to 
r$uce ! /r5g? ( ! sk9 to su* an ext5t t 
! frame jumps up out ( ! wat]4  ,!re is 
a well-kn[n case 9 :i* ! diff]5ce betwe5
 ! /r5g? ( ! sk9s ( two liquids may be  
ei!r a s\rce ( vexation or1 if we "k h[ 
to make use ( x1 an advantage4 ,if y    
spill grease on y\r coat y c take x out 
v well ) b5z9e4 ,n[ if y apply b5z9e to 
! grease1 & !n apply fre% b5z9e to t    
already !re1 y h ?is result--!re is !n  
greasy b5z9e on ! coat to :i* y apply   

fre% b5z9e4 ,x s happ5s t greasy b5z9e  
has a /rong] sk9 ?an pure b5z9e4 ,!     
greasy b5z9e !re=e plays at tug-(-w> )  
pure b5z9e1 & be+ /rong] w9s & runs away
 9 all directions1 & ! m y apply b5z9e !
 m ! greasy b5z9e runs away c>ry+ !     
grease ) x4 ,b if y foll[ ! directions  
on ! bottle1 & fir/ make a r+ ( clean   
b5z9e r\nd ! grease-spot1 & !n apply    
b5z9e to ! grease1 y !n h ! greasy b5z9e
 runn+ away f ! pure b5z9e r+ & heap+   
itself toge!r 9 ! middle1 & escap+ into 
! fre% rag t y apply1 s t ! grease is   
all ( x remov$4  ,!re is a diff]5ce aga9
 betwe5 hot & cold grease1 z y may see1 
:5 y get home1 if y wat* a common c&le  
burn+4 ,close to ! flame ! grease is    
hott] ?an x is ne> ! outside4 ,x has    
!re=e a weak] sk91 & s a p]petual       
circulation is kept up1 & ! grease runs 
out on ! surface & back aga9 bel[1 c>ry+
 little specks ( du/ :i* make ?is       
movem5t visible1 & mak+ ! c&le burn     
regul>ly4  ,y probably "k h[ to take out
 grease-/a9s ) a hot pok] & blott+-pap]4

 ,"h aga9 ! same k9d ( action is go+ on4
  ,a piece ( light$ camphor float+ 9    
wat] is ano!r example ( movem5t set up  
by diff]5ces 9 ! /r5g? ( ! sk9 ( wat]   
ow+ to ! action ( ! camphor4  ,i w give 
only "o m example4  ,if y are pa9t+ 9   
wat]-col\rs on greasy pap] or c]ta9 %9y 
surfaces ! pa9t w n lie smoo?ly on !    
pap]1 b runs toge!r 9 ! well-kn[n way2 a
 v little ox-gall1 h[ev]1 makes x lie   
p]fectly1 because ox-gall s r$uces !    
/r5g? ( ! sk9 ( wat] t x w wet surfaces 
t pure wat] w n wet4 ,?is r$uction ( !  
surface t5sion y c see if ,i use ! same 
wire frame a ?ird "t4 ,! e!r has n[     
evaporat$1 & ,i c aga9 make x re/ aga9/ 
! surface ( ! wat]1 b v soon aft] ,i t\*
 ! wat] ) a bru% conta9+ ox-gall ! frame
 jumps up z sudd5ly z be=e4  ,x is q    
unnecess>y t ,i %\ld any fur!r insi/ ^u 
! fact t ! outside ( a liquid acts z if 
x 7 a p]fectly ela/ic sk9 /ret*$ ) a    
c]ta9 def9ite =ce4  ,suppose n[ t y take
 a small quantity ( wat]1 say z mu* z   
w\ld g into a nut-%ell1 & sudd5ly let x 

g1 :at w happ58 ,( c\rse x w fall d[n & 
be da%$ aga9/ ! gr\nd4 ,or aga91 suppose
 y take ! same quantity ( wat] & lay x  
c>efully ^u a cake ( p>aff9 wax du/$ ov]
 ) lycopodium :i* x does n wet1 :at w   
happ58 ,"h aga9 ! weight ( ! drop--t :i*
 makes x fall if n held--w squeeze x    
aga9/ ! p>aff9 & make x spread out into 
a flat cake4 ,:at w\ld happ5 if ! weight
 ( ! drop or ! =ce pull+ x d[nw>ds c\ld 
be prev5t$ f act+8 ,9 su* a case ! drop 
w\ld only feel ! effect ( ! ela/ic sk91 
:i* w\ld try to pull x into su* a =m z  
to make ! surface z small z possible4 ,x
 w\ld 9 fact rapidly become a p]fectly  
r\nd ball1 because 9 no o!r way c s     
small a surface be obta9$4 ,if1 in/ead (
 tak+ s mu* wat]1 we 7 to take a drop   
ab\t z l>ge z a p9's head1 !n ! weight  
:i* t5ds to squeeze x out or make x fall
 w\ld be f> less1 :ile ! sk9 w\ld be j z
 /rong1 & w\ld 9 reality h a great]     
m\ld+ p[]1 ?\gh :y ,i _c n[ expla94 ,we 
%\ld !re=e expect t by tak+ a           
suffici5tly small quantity ( wat] !     

m\ld+ p[] ( ! sk9 w\ld ultimately be    
able almo/ entirely to c\nt]act ! weight
 ( ! drop1 s t v small drops %\ld appe> 
l p]fect little balls4 ,if y h f\nd any 
difficulty 9 foll[+ ?is argum5t1 a v    
simple illu/ration w make x cle>4 ,_m ( 
y probably "k h[ by fold+ pap] to make  
?is little ?+ :i* ,i hold 9 my h& 7,fig4
 #ae74 ,x is call$ a cat-box1 because ( 
its p[] ( dispell+ cats :5 x is fill$ ) 
wat] & well ?r[n4 ,?is "o1 l>ge en\gh to
 hold ab\t half a p9t1 is made out ( a  
small piece ( ! ,times newspap]4 ,y may 
fill x ) wat] & c>ry x ab\t & ?r[ x )   
y\r full p[]1 & ! /r5g? ( ! pap] sk9 is 
suffici5t to hold x toge!r until x hits 
any?+1 :5 ( c\rse x bur/s & ! wat] comes
 out4 ,on ! o!r h&1 ! l>ge "o made out (
 a :ole %eet ( ! ,times is b>ely able to
 )/& ! weight ( ! wat] t x w hold4 ,x is
 only j /rong en\gh to all[ ( its be+   
fill$ & c>ri$1 & !n x may be dropp$ f a 
height1 b y _c ?r[ x4 ,9 ! same way !   
weak] sk9 ( a liquid w n make a l>ge    
quantity take ! %ape ( a ball1 b x w    

m\ld a m9ute drop s p]fectly t y _c tell
 by look+ at x t x is n p]fectly r\nd e 
way4 ,?is is mo/ easily se5 )           
quicksilv]4 ,a l>ge quantity rolls ab\t 
l a flat cake1 b ! v small drops obta9$ 
by ?r[+ "s viol5tly on ! table & s      
break+ x up appe> p]fectly r\nd4 ,y c   
see ! same diff]5ce 9 ! beads ( gold n[ 
^u ! scre5 7,fig4 #af74 ,!y are n[      
solid1 b !y 7 melt$ & !n all[$ to cool  
)\t be+ di/urb$4 ,?\gh ! l>ge bead is   
flatt5$ by its weight1 ! small "o appe>s
 p]fectly r\nd4 ,f9ally1 y may see !    
same ?+ ) wat] if y du/ a little        
lycopodium on ! table4 ,!n wat] fall+ w 
roll itself up into p]fect little balls4
 ,y may ev5 see ! same ?+ on a du/y day 
if y wat] ! road ) a wat]-pot4          
,illu/ration3 ,fig4 #ae4  ,illu/ration3 
,fig4 #af4  ,if x 7 n = ! weight (      
liquids1 t is ! =ce ) :i* !y are pull$  
d[n t[>ds ! e>?1 l>ge drops w\ld be z   
p]fectly r\nd z small ones4 ,?is 0 fir/ 
beautifully %[n by ,plateau1 ! bl9d     
exp]im5tali/1 :o plac$ "o liquid inside 

ano!r :i* is equally heavy1 & ) :i* x   
does n mix4 ,alcohol is light] ?an oil1 
:ile wat] is heavi]1 b a suitable       
mixture ( alcohol & wat] is j z heavy z 
oil1 & s oil does n ei!r t5d to rise or 
to fall :5 imm]s$ 9 su* a mixture4 ,i h 
9 front ( ! lant]n a glass box conta9+  
alcohol & wat]1 & by means ( a tube ,i  
%all sl[ly all[ oil to fl[ 94 ,y see t z
 ,i remove ! tube x becomes a p]fect    
ball z l>ge z a walnut4 ,!re are n[ two 
or ?ree ( ^! balls ( oil all p]fectly   
r\nd4 ,i want y to notice t :5 ,i hit !m
 on "o side ! l>ge balls recov] _! %ape 
sl[ly1 :ile ! small ones become r\nd    
aga9 mu* m quickly4 ,!re is a v         
beautiful effect :i* c be produc$ ) ?is 
app>atus1 & ?\gh x is n necess>y to ref]
 to x1 x is well wor? :ile n[ t !       
app>atus is set up to %[ x to y4 ,9 !   
middle ( ! box !re is an axle ) a disc  
^u x to :i* ,i c make ! oil adh]e4 ,n[  
if ,i sl[ly turn ! wire & disc ! oil w  
turn also4 ,z ,i gradually increase !   
spe$ ! oil t5ds to fly away 9 all       

directions1 b ! ela/ic sk9 reta9s x4 ,! 
result is t ! ball becomes flatt5$ at   
its poles l ! e>? itself4 ,on increas+ !
 spe$1 ! t5d5cy ( ! oil to get away is  
at la/ too mu* = ! ela/ic sk91 & a r+   
breaks away 7,fig4 #ag71 :i* almo/      
imm$iately contracts aga9 on to ! re/ ( 
! ball z ! spe$ falls4 ,if ,i turn x    
suffici5tly fa/ ! r+ breaks up into a   
s]ies ( balls :i* y n[ see4 ,"o _c help 
be+ rem9d$ ( ! heav5ly bodies by ?is    
beautiful exp]im5t ( ,plateau's1 = y see
 a c5tral body & a s]ies ( balls (      
diff]5t sizes all travell+ r\nd 9 ! same
 direction 7,fig4 #ah72 b ! =ces :i* are
 act+ 9 ! two cases are totally di/9ct1 
& :at y see has no?+ :atev] to d ) ! sun
 & ! planets4  ,illu/ration3 ,fig4 #ag4 
,illu/ration3 ,fig4 #ah4  ,we h ?us se5 
t a l>ge ball ( liquid c be m\ld$ by !  
ela/icity ( its sk9 if ! di/urb+ effect 
( its weight is neutraliz$1 z 9 ! la/   
exp]im5t4 ,?is di/urb+ effect is        
practically ( no acc\nt 9 ! case ( a    
soap-bubble1 because x is s ?9 t x h>dly

 weighs any?+4 ,y all "k1 ( c\rse1 t a  
soap-bubble is p]fectly r\nd1 & n[ y "k 
:y2 x is because ! ela/ic film1 try+ to 
become z small z x c1 mu/ take ! =m :i* 
has ! smalle/ surface = its cont5t1 & t 
=m is ! sph]e4 ,i want y to notice "h1 z
 ) ! oil1 t a l>ge bubble oscillates mu*
 m sl[ly ?an a small "o :5 knock$ out ( 
%ape ) a bat cov]$ ) baize or wool4  ,! 
*ief result t ,i h endeav\r$ to make    
cle> to-day is ?is4 ,! outside ( a      
liquid acts z if x 7 an ela/ic sk91 :i* 
w1 z f> z x is able1 s m\ld ! liquid )9 
x t x %all be z small z possible4       
,g5]ally ! weight ( liquids1 especially 
:5 !re is a l>ge quantity1 is too mu* = 
! feebly ela/ic sk91 & its p[] may n be 
notic$4 ,! di/urb+ effect ( weight is   
got rid ( by imm]s+ "o liquid 9 ano!r   
:i* is equally heavy ) :i* x does n mix1
 & x is h>dly notic$ :5 v small drops   
are exam9$1 or :5 a bubble is bl[n1 = 9 
^! cases ! weight is almo/ no?+1 :ile ! 
ela/ic p[] ( ! sk9 is j z great z ev]4  
,,lecture ,,ii4   ,i did n 9 ! la/      

lecture by any direct exp]im5t %[ t a   
soap-film or bubble is really ela/ic1 l 
a piece ( /ret*$ india-rubb]4  ,a       
soap-bubble consi/+1 z x does1 ( a ?9   
lay] ( liquid1 :i* mu/ h ( c\rse bo? an 
inside & an outside surface or sk91 mu/ 
be ela/ic1 & ?is is easily %[n 9 _m     
ways4 ,p]haps ! easie/ way is to tie a  
?read across a r+ r loosely1 & !n to dip
 ! r+ into soap wat]4 ,on tak+ x out !re
 is a film /ret*$ ov] ! r+1 9 :i* !     
?read moves ab\t q freely1 z y c see ^u 
! scre54 ,b if ,i break ! film on "o    
side1 !n imm$iately ! ?read is pull$ by 
! film on ! o!r side z f> z x c g1 & x  
is n[ tight 7,fig4 #ai74 ,y w also      
notice t x is "p ( a p]fect circle1     
because t =m makes ! space on "o side z 
great1 & !re=e on ! o!r side1 :]e ! film
 is1 z small1 z possible4 ,or aga91 9   
?is second r+ ! ?read is d\ble = a %ort 
di/ance 9 ! middle4 ,if ,i break ! film 
betwe5 ! ?reads !y are at once pull$    
ap>t1 & are pull$ into a p]fect circle  
7,fig4 #bj71 because t is ! =m :i* makes

 ! space )9 x z great z possible1 &     
!re=e leaves ! space outside x z small z
 possible4 ,y w also notice1 t ?\gh !   
circle w n all[ itself to be pull$ out (
 %ape1 yet x c move ab\t 9 ! r+ q       
freely1 because su* a movem5t does n    
make any diff]5ce to ! space outside x4 
,illu/ration3 ,fig4 #ai4  ,illu/ration3 
,fig4 #bj4  ,illu/ration3 ,fig4 #ba4    
,illu/ration3 ,fig4 #bb4  ,i h n[ bl[n a
 bubble ^u a r+ ( wire4 ,i %all hang a  
small r+ ^u x1 & to %[ m cle>ly :at is  
happ5+1 ,i %all bl[ a little smoke into 
! bubble4 ,n[ t ,i h brok5 ! film inside
 ! l[] r+1 y w see ! smoke be+ driv5 out
 & ! r+ lift$ up1 bo? ( :i* %[ ! ela/ic 
nature ( ! film4 ,or aga91 ,i h bl[n a  
bubble on ! end ( a wide pipe2 on hold+ 
! op5 end ( ! pipe to a c&le flame1 !   
outru%+ air bl[s out ! flame at once1   
:i* %[s t ! soap-bubble is act+ l an    
ela/ic bag 7,fig4 #ba74 ,y n[ see t1 ow+
 to ! ela/ic sk9 ( a soap-bubble1 ! air 
inside is "u pressure & w get out if x  
c4 ,:i* w\ld y ?9k w\ld squeeze ! air   

inside x mo/1 a l>ge or a small bubble8 
,we w f9d out by try+1 & !n see if we c 
tell :y4 ,y n[ see two pipes ea* ) a    
tap4 ,^! are jo9$ toge!r by a ?ird pipe 
9 :i* !re is a ?ird tap4 ,i w fir/ bl[  
"o bubble & %ut x (f ) ! tap #a 7,fig4  
#bb71 & !n ! o!r1 & %ut x (f ) ! tap #b4
 ,!y are n[ ne>ly equal 9 size1 b ! air 
_c yet pass f "o to ! o!r because ! tap 
#c is turn$ (f4 ,n[ if ! pressure 9 !   
l>ge/ "o is greate/ x w bl[ air into !  
o!r :5 ,i op5 ?is tap1 until !y are     
equal 9 size2 if1 on ! o!r h&1 !        
pressure 9 ! small "o is greate/1 x w   
bl[ air into ! l>ge "o1 & w itself get  
small] until x has q disappe>$4 ,we w n[
 try ! exp]im5t4 ,y see imm$iately t ,i 
op5 ! tap #c ! small bubble %uts up &   
bl[s out ! l>ge "o1 ?us %[+ t !re is a  
great] pressure 9 a small ?an 9 a l>ge  
bubble4 ,! directions 9 :i* ! air & !   
bubble move is indicat$ 9 ! figure by   
arr[s4 ,i want y p>ticul>ly to notice & 
rememb] ?is1 because ?is is an exp]im5t 
on :i* a great deal dep5ds4 ,to impress 

?is ^u y\r memory ,i %all %[ ! same ?+ 9
 ano!r way4 ,!re is 9 front ( ! lant]n a
 little tube %ap$ l a ,u half fill$ )   
wat]4 ,"o end ( ! ,u is jo9$ to a pipe  
on :i* a bubble c be bl[n 7,fig4 #bc74  
,y w n[ be able to see h[ ! pressure    
*anges z ! bubble increases 9 size1     
because ! wat] w be displac$ m :5 !     
pressure is m1 & less :5 x is less4 ,n[ 
t !re is a v small bubble1 ! pressure z 
measur$ by ! wat] is ab\t "o qu>t] ( an 
in* on ! scale4 ,! bubble is gr[+ & !   
pressure indicat$ by ! wat] 9 ! gauge is
 fall+1 until1 :5 ! bubble is d\ble its 
=m] size1 ! pressure is only half :at x 
02 & ?is is always true1 ! small] !     
bubble ! great] ! pressure4 ,z ! film is
 always /ret*$ ) ! same =ce1 :atev] size
 ! bubble is1 x is cle> t ! pressure    
inside c only dep5d ^u ! curvature ( a  
bubble4 ,9 ! case ( l9es1 our ord9>y    
language tells u1 t ! l>g] a circle is !
 less is its curvature2 a piece ( a     
small circle is said to be a quick or a 
%>p curve1 :ile a piece ( a great circle

 is only slightly curv$2 & if y take a  
piece ( a v l>ge circle inde$1 !n y _c  
tell x f a /raight l9e1 & y say x is n  
curv$ at all4 ,) a "p ( ! surface ( a   
ball x is j ! same--! l>g] ! ball ! less
 x is curv$2 & if ! ball is v l>ge      
inde$1 say #hjjj miles across1 y _c tell
 a small piece ( x f a true plane4      
,level wat] is "p ( su* a surface1 & y  
"k t /ill wat] 9 a bas9 appe>s p]fectly 
flat1 ?\gh 9 a v l>ge lake or ! sea y c 
see t x is curv$4 ,we h se5 t 9 l>ge    
bubbles ! pressure is little & !        
curvature is little1 :ile 9 small       
bubbles ! pressure is great & !         
curvature is great4 ,! pressure & !     
curvature rise & fall toge!r4 ,we h n[  
le>nt ! lesson :i* ! exp]im5t ( ! two   
bubbles1 "o bl[n out by ! o!r1 tea*es u4
  ,illu/ration3 ,fig4 #bc4              
,illu/ration3 ,fig4 #bd4  ,a ball or    
sph]e is n ! only =m :i* y c give to a  
soap-bubble4 ,if y take a bubble betwe5 
two r+s1 y c pull x out until at la/ x  
has ! %ape ( a r\nd /raight tube or     

cyl9d] z x is call$4 ,we h spok5 ( !    
curvature ( a ball or sph]e2 n[ :at is !
 curvature ( a cyl9d]8 ,look$ at        
sideways1 ! edge ( ! wood5 cyl9d] ^u !  
table appe>s /raight1 i4 e4 n curv$ at  
all2 b look$ at f above x appe>s r\nd1 &
 is se5 to h a def9ite curvature 7,fig4 
#bd74 ,:at !n is ! curvature ( ! surface
 ( a cyl9d]8 ,we h se5 t ! pressure 9 a 
bubble dep5ds ^u ! curvature :5 !y are  
sph]es1 & ?is is true :atev] %ape !y h4 
,if1 !n1 we f9d :at siz$ sph]e w produce
 ! same pressure ^u ! air inside t a    
cyl9d] does1 !n we %all "k t ! curvature
 ( ! cyl9d] is ! same z t ( ! sph]e :i* 
balances x4 ,n[ at ea* end ( a %ort tube
 ,i %all bl[ an ord9>y bubble1 b ,i %all
 pull ! l[] bubble by means ( ano!r tube
 into ! cyl9drical =m1 & f9ally bl[ 9 m 
or less air until ! sides ( ! cyl9d] are
 p]fectly /raight4 ,t is n[ done 7,fig4 
#be71 & ! pressure 9 ! two bubbles mu/  
be exactly ! same1 z !re is a free      
passage ( air betwe5 ! two4 ,on measur+ 
!m y see t ! sph]e is exactly d\ble !   

cyl9d] 9 diamet]4 ,b ?is sph]e has only 
half ! curvature t a sph]e half its     
diamet] w\ld h4 ,!re=e ! cyl9d]1 :i* we 
"k has ! same curvature t ! l>ge sph]e  
has1 because ! two balance1 has only    
half ! curvature ( a sph]e ( its own    
diamet]1 & ! pressure 9 x is only half t
 9 a sph]e ( its own diamet]4           
,illu/ration3 ,fig4 #be4  ,i mu/ n[ make
 "o m /ep 9 expla9+ ?is "q ( curvature4 
,n[ t ! cyl9d] & sph]e are balanc$ ,i   
%all bl[ 9 m air1 mak+ ! sph]e l>g]2 :at
 w happ5 to ! cyl9d]8 ,! cyl9d] is1 z y 
see1 v %ort2 w x become bl[n out too1 or
 :at w happ58 ,n[ t ,i am bl[+ 9 air y  
see ! sph]e enl>g+1 ?us reliev+ !       
pressure2 ! cyl9d] develops a wai/1 x is
 no long] a cyl9d]1 ! sides are curv$   
inw>ds4 ,z ,i g on bl[+ & enl>g+ !      
sph]e1 !y g on fall+ inw>ds1 b n        
indef9itely4 ,if ,i 7 to bl[ ! upp]     
bubble till x 0 ( an enorm\s size !     
pressure w\ld become extremely small4   
,let u make ! pressure no?+ at all at   
once by simply break+ ! upp] bubble1 ?us

 all[+ ! air a free passage f ! inside  
to ! outside ( :at 0 ! cyl9d]4 ,let me  
repeat ?is exp]im5t on a l>g] scale4 ,i 
h two l>ge glass r+s1 betwe5 :i* ,i c   
draw out a film ( ! same k9d4 ,n only is
 ! outl9e ( ! soap-film curv$ inw>ds1 b 
x is exactly ! same z ! small] "o 9 %ape
 7,fig4 #bf74 ,z !re is n[ no pressure  
!re ought to be no curvature1 if :at ,i 
h said is correct4 ,b look at !         
soap-film4 ,:o w\ld v5ture to say t t 0 
n curv$8 & yet we _h satisfi$ ourselves 
t ! pressure & ! curvature rose & fell  
toge!r4 ,we n[ seem to h come to an     
absurd conclusion4 ,because ! pressure  
is r$uc$ to no?+ we say ! surface mu/ h 
no curvature1 & yet a glance is         
suffici5t to %[ t ! film is s f> curv$ z
 to h a mo/ elegant wai/4 ,n[ look at ! 
pla/] model on ! table1 :i* is a model (
 a ma!matical figure :i* also has a     
wai/4  ,illu/ration3 ,fig4 #bf4  ,let u 
!re=e exam9e ?is ca/ m 9 detail4 ,i h a 
disc ( c>d :i* has exactly ! same       
diamet] z ! wai/ ( ! ca/4 ,i n[ hold ?is

 edgeways aga9/ ! wai/ 7,fig4 #bg71 &   
?\gh y c see t x does n fit ! :ole      
curve1 x fits ! "p close to ! wai/      
p]fectly4 ,?is !n %[s t ?is "p ( ! ca/  
w\ld appe> curv$ inw>ds if y look$ at x 
sideways1 to ! same ext5t t x w\ld appe>
 curv$ outw>ds if y c\ld see x f above4 
,s consid]+ ! wai/ only1 x is curv$ bo? 
t[>ds ! inside & also away f ! inside   
accord+ to ! way y look at x1 & to !    
same ext5t4 ,! curvature inw>ds w\ld    
make ! pressure inside less1 & !        
curvature outw>ds w\ld make x m1 & z !y 
are equal !y j balance1 & !re is no     
pressure at all4 ,if we c\ld 9 ! same   
way exam9e ! bubble ) ! wai/1 we %\ld   
f9d t ?is 0 true n only at ! wai/ b at e
 "p ( x4 ,any curv$ surface l ?is :i* at
 e po9t is equally curv$ opposite ways1 
is call$ a surface ( no curvature1 & s  
:at seem$ an absurdity is n[ expla9$4   
,n[ ?is surface1 :i* is ! only "o ( !   
k9d symmetrical ab\t an axis1 except a  
flat surface1 is call$ a cat5oid1       
because x is l a *a91 z y w see         

directly1 &1 z y "k1 cat5a is ! ,lat9 = 
a *a94 ,i %all n[ hang a *a9 9 a loop f 
a level /ick1 & ?r[ a /rong light ^u x1 
s t y c see x well 7,fig4 #bh74 ,?is is 
exactly ! same %ape z ! side ( a bubble 
drawn out betwe5 two r+s1 & op5 at ! end
 to ! air4#a  ,illu/ration3 ,fig4 #bg4  
,illu/ration3 ,fig4 #bh4  ,footnote #a3 
,if ! read] f9ds ^! geometrical         
relations too difficult to foll[1 he or 
%e %\ld skip ! next pages1 & g on aga9  
at ,we h f\nd4444 p4 #gg4  ,let u n[    
take two r+s1 & hav+ plac$ a bubble     
betwe5 !m1 gradually alt] ! pressure4 ,y
 c tell :at ! pressure is by look+ at ! 
"p ( ! film :i* cov]s ei!r r+1 :i* ,i   
%all call ! cap4 ,?is mu/ be "p ( a     
sph]e1 & we "k t ! curvature ( ?is & !  
pressure inside rise & fall toge!r4 ,i h
 n[ adju/$ ! bubble s t x is a ne>ly    
p]fect sph]e4 ,if ,i bl[ 9 m air ! caps 
become m curv$1 %[+ an increas$         
pressure1 & ! sides bulge out ev5 m ?an 
^? ( a sph]e 7,fig4 #bi74 ,i h n[ br\ght
 ! :ole bubble back to ! sph]ical =m4 ,a

 little increas$ pressure1 z %[n by !   
increas$ curvature ( ! cap1 makes !     
sides bulge m2 a little less pressure1 z
 %[n by ! flatt5+ ( ! caps1 makes !     
sides bulge less4 ,n[ ! sides are       
/raight1 & ! cap1 z we h already se51   
=ms "p ( a sph]e ( twice ! diamet] ( !  
cyl9d]4 ,i am /ill fur!r r$uc+ !        
pressure until ! caps are plane1 t is1 n
 curv$ at all4 ,!re is n[ no pressure   
inside1 & !re=e ! sides h1 z we h       
already se51 tak5 ! =m ( a hang+ *a92 & 
n[1 f9ally1 ! pressure inside is less   
?an t outside1 z y c see by ! caps be+  
drawn inw>ds1 & ! sides h ev5 a small]  
wai/ ?an ! cat5oid4 ,we h n[ se5 sev5   
curves z we gradually r$uc$ ! pressure1 
namely--       #a4 ,outside ! sph]e4    
#b4 ,! sph]e4       #c4 ,betwe5 ! sph]e 
& ! cyl9d]4       #d4 ,! cyl9d]4        
#e4 ,betwe5 ! cyl9d] & ! cat5oid4       
#f4 ,! cat5oid4       #g4 ,inside !     
cat5oid4  ,illu/ration3 ,fig4 #bi4  ,n[ 
,i am n go+ to say mu* m ab\t all ^!    
curves1 b ,i mu/ ref] to ! v curi\s     

prop]ties t !y possess4 ,9 ! fir/ place1
 !y mu/ all ( !m h ! same curvature 9 e 
"p z ! portion ( ! sph]e :i* =ms ! cap2 
9 ! second place1 !y mu/ all be ! curves
 ( ! lea/ possible surface :i* c enclose
 ! air & jo9 ! r+s z well4 ,& f9ally1   
s9ce !y pass ins5sibly f "o to ! o!r z !
 pressure gradually *anges1 ?\gh !y are 
di/9ct curves !re mu/ be "s curi\s &    
intimate relation betwe5 !m4 ,?is ?\gh x
 is a little difficult1 ,i %all expla94 
,if ,i 7 to say t ^! curves are !       
r\lettes ( ! conic sections ,i suppose  
,i %\ld al>m y1 & at ! same "t expla9   
no?+1 s ,i %all n put x 9 t way2 b      
in/ead1 ,i %all %[ y a simple exp]im5t  
:i* w ?r[ "s light ^u ! subject1 :i* y c
 try = y\rselves at home4  ,illu/ration3
 ,fig4 #cj4  ,i h "h a common b$room    
c&le/ick ) a flat r\nd base4 ,hold !    
c&le/ick exactly upright ne> to a :ite  
wall1 !n y w see ! %ad[ ( ! base on !   
wall bel[1 & ! outl9e ( ! %ad[ is a     
symmetrical curve1 call$ a hyp]bola4    
,gradually tilt ! c&le away f ! wall1 y 

w !n notice ! sides ( ! %ad[ gradually  
bran* away less & less1 & :5 y h s f>   
tilt$ ! c&le away f ! wall t ! flame is 
exactly above ! edge ( ! base1--& y w "k
 :5 ?is is ! case1 because !n ! fall+   
grease w j fall on ! edge ( ! c&le/ick &
 spla% on to ! c>pet1--,i h x s n[1--!  
sides ( ! %ad[ ne> ! floor w be almo/   
p>allel 7,fig4 #cj71 & ! %ape ( ! %ad[ w
 h become a curve1 kn[n z a p>abola2 &  
n[ :5 ! c&le/ick is /ill m tilt$1 s t ! 
grease misses ! base altoge!r & falls 9 
a g5tle /ream ^u ! c>pet1 y w see t !   
sides ( ! %ad[ h curl$ r\nd & met on !  
wall1 & y n[ h a curve l an oval1 except
 t ! two ends are alike1 & ?is is call$ 
an ellipse4 ,if y g on tilt+ ! c&le/ick1
 !n :5 ! c&le is j level1 & ! grease    
p\r+ away1 ! %ad[ w be almo/ a circle2 x
 w\ld be an exact circle if ! flame did 
n fl>e up4 ,n[ if y g on tilt+ ! c&le1  
until at la/ ! c&le/ick is upside d[n1 !
 curves already obta9$ w be reproduc$ 9 
! rev]se ord]1 b above in/ead ( bel[ y4 
,y may well ask :at all ?is has to d ) a

 soap-bubble4 ,y w see 9 a mom5t4 ,:5 y 
light a c&le1 ! base ( ! c&le/ick ?r[s !
 space beh9d x into d>kness1 & ! =m (   
?is d>k space1 :i* is ev]y:]e r\nd l !  
base1 & gets l>g] z y get fur!r f !     
flame1 is a cone1 l ! wood5 model on !  
table4 ,! %ad[ ca/ on ! wall is ( c\rse 
! "p ( ! wall :i* is )9 ?is cone4 ,x is 
! same %ape t y w\ld f9d if y 7 to cut a
 cone ?r\gh ) a saw1 & s ^! curves :i*  
,i h %[n y are call$ conic sections4 ,y 
c see "s ( !m already made 9 ! wood5    
model on ! table4 ,if y look at !       
diagram on ! wall 7,fig4 #ca71 y w see a
 complete cone at fir/ upright 7,a71 !n 
be+ gradually tilt$ ov] into ! positions
 t ,i h specifi$4 ,! black l9e 9 ! upp] 
"p ( ! diagram %[s :]e ! cone is cut    
?r\gh1 & ! %ad$ area bel[ %[s ! true    
%ape ( ^! %ad[s1 or pieces cut (f1 :i*  
are call$ sections4 ,n[ 9 ea* ( ^!      
sections !re are ei!r "o or two po9ts1  
ea* ( :i* is call$ a focus1 & ^! are    
indicat$ by conspicu\s dots4 ,9 ! case (
 ! circle 7,d ,fig4 #ca71 ?is po9t is   

also ! c5tre4 ,n[ if ?is circle is made 
to roll l a :eel along ! /raight l9e    
drawn j bel[ x1 a p5cil at ! c5tre w    
rule ! /raight l9e :i* is dott$ 9 ! l[] 
"p ( ! figure2 b if we 7 to make :eels (
 ! %apes ( any ( ! o!r sections1 a p5cil
 at ! focus w\ld c]ta9ly n draw a       
/raight l9e4 ,:at %ape x w\ld draw is n 
at once evid5t4 ,fir/ consid] any ( !   
elliptic sections 7,c1 ,e1 or ,f7 :i* y 
see on ei!r side ( ! circle4 ,if ^! 7   
:eels1 & 7 made to roll1 ! p5cil z x    
mov$ along w\ld also move up & d[n1 & ! 
l9e x w\ld draw is %[n dott$ z be=e 9 ! 
l[] "p ( ! figure4 ,9 ! same way ! o!r  
curves1 if made to roll along a /raight 
l9e1 w\ld cause p5cils at _! focal po9ts
 to draw ! o!r dott$ l9es4              
,illu/ration3 ,fig4 #ca4  ,we are n[    
almo/ able to see :at ! conic section   
has to d ) a soap-bubble4 ,:5 a         
soap-bubble 0 bl[n betwe5 two r+s1 & !  
pressure inside 0 v>i$1 its outl9e w5t  
?r\gh a s]ies ( =ms1 "s ( :i* are       
repres5t$ by ! dott$ l9es 9 ! l[] "p ( !

 figure1 b 9 e case !y c\ld h be5       
accurately drawn by a p5cil at ! focus (
 a suitable conic section made to roll  
on a /raight l9e4 ,i call$ "o ( ! bubble
 =ms1 if y rememb]1 by its "n1 cat5oid2 
?is is produc$ :5 !re is no pressure4 ,!
 dott$ curve 9 ! second figure ,b is ?is
 "o2 & to %[ t ?is cat5>y c be s drawn1 
,i %all roll ^u a /raight edge a bo>d   
made into ! =m ( ! correspond+ section1 
:i* is call$ a p>abola1 & let ! *alk at 
its focus draw its curve ^u ! black     
bo>d4 ,!re is ! curve1 & x is z ,i said1
 exactly ! curve t a *a9 makes :5 hung  
by its two ends4 ,n[ t a *a9 is s hung y
 see t x exactly lies ov] ! *alk l9e4   
,all ?is is r difficult to und]/&1 b z  
^! =ms :i* a soap-bubble takes af=d a   
beautiful example ( ! mo/ important     
pr9ciple ( cont9uity1 ,i ?\ght x w\ld be
 a pity to pass x by4 ,x may be put 9   
?is way4 ,a s]ies ( bubbles may be bl[n 
betwe5 a pair ( r+s4 ,if ! pressures are
 diff]5t ! curves mu/ be diff]5t4 ,9    
bl[+ !m ! pressures sl[ly & cont9u\sly  

*ange1 & s ! curves _c be altoge!r      
diff]5t 9 k9d4 ,?\gh !y may be diff]5t  
curves1 !y also mu/ pass sl[ly &        
cont9u\sly "o into ! o!r4 ,we f9d !     
bubble curves c be drawn by roll+ :eels 
made 9 ! %ape ( ! conic sections on a   
/raight l9e1 & s ! conic sections1 ?\gh 
di/9ct curves1 mu/ pass sl[ly &         
cont9u\sly "o into ! o!r4 ,?is we saw 0 
! case1 because z ! c&le 0 sl[ly tilt$ !
 curves did z a fact sl[ly & ins5sibly  
*ange f "o to ! o!r4 ,!re 0 only "o     
p>abola1 & t 0 =m$ :5 ! side ( ! cone 0 
p>allel to ! plane ( section1 t is :5 ! 
fall+ grease j t\*$ ! edge ( ! c&le/ick2
 !re is only "o bubble ) no pressure1 ! 
cat5oid1 & ?is is drawn by roll+ !      
p>abola4 ,z ! cone is gradually incl9$  
m1 s ! sections become at fir/ long     
ellipses1 :i* gradually become m & m    
r\nd until a circle is rea*$1 aft] :i*  
!y become m & m n>r[ until a l9e is     
rea*$4 ,! correspond+ bubble curves are 
produc$ by a gradually increas+         
pressure1 &1 z ! diagram %[s1 ^! bubble 

curves are at fir/ wavy 7,c71 !n !y     
become /raight :5 a cyl9d] is =m$ 7,d71 
!n !y become wavy aga9 7,e & ,f71 & at  
la/1 :5 ! cutt+ plane1 i4 e4 ! black l9e
 9 ! upp] figure1 passes ?r\gh ! v]tex (
 ! cone ! waves become a s]ies (        
semicircles1 indicat+ ! ord9>y sph]ical 
soap-bubble4 ,n[ if ! cone is incl9$ ev]
 s little m a new %ape ( section is se5 
7,g71 & ?is be+ roll$1 draws a curi\s   
curve ) a loop 9 x2 b h[ ?is is s x w\ld
 take too long to expla94 ,x w\ld also  
take too long to trace ! fur!r positions
 ( ! cone1 & to trace ! correspond+     
sections & bubble curves got by roll+   
!m4 ,c>eful inspection ( ! diagram may  
be suffici5t to enable y to "w out =    
y\rselves :at w happ5 9 all cases4 ,i   
%\ld expla9 t ! bubble surfaces are     
obta9$ by sp9n+ ! dott$ l9es ab\t !     
/raight l9e 9 ! l[] "p ( ,fig4 #ca z an 
axis4  ,z y w soon f9d out if y try1 y  
_c make ) a soap-bubble a great l5g? (  
any ( ^! curves at "o "t1 b y may get   
pieces ( any ( !m ) no m app>atus ?an a 

few wire r+s1 a pipe1 & a little soap & 
wat]4 ,y c ev5 see ! :ole ( "o ( ! loops
 ( ! dott$ curve ( ! fir/ figure 7,a71  
:i* is call$ a nodoid1 n a complete r+1 
= t is un/able1 b a "p ( su* a r+4 ,take
 a piece ( wire or a mat*1 & fa/5 "o end
 to a piece ( lead1 s t x w /& upright 9
 a di% ( soap wat]1 & project half an   
in* or s4 ,hold ) "o h& a %eet ( glass  
re/+ on ! mat* 9 middle1 & bl[ a bubble 
9 ! wat] aga9/ ! mat*4 ,z soon z x t\*es
 ! glass plate1 :i* %\ld be wett$ ) !   
soap solution1 x w become a cyl9d]1 :i* 
w meet ! glass plate 9 a true circle4   
,n[ v sl[ly incl9e ! plate4 ,! bubble w 
at once "w r\nd to ! l[e/ side1 & try to
 pull itself away f ! mat* /ick1 & 9 do+
 s x w develop a loop ( ! nodoid1 :i*   
w\ld be exactly true 9 =m if ! mat* or  
wire 7 slightly b5t1 s z to meet bo? !  
glass & ! surface ( ! soap wat] at a "r 
angle4 ,i h describ$ ?is 9 detail1      
because x is n g5]ally kn[n t a complete
 loop ( ! nodoid c be made ) a          
soap-bubble4  ,illu/ration3 ,fig4 #cb4  

,illu/ration3 ,fig4 #cc4  ,we h f\nd t !
 pressure 9 a %ort cyl9d] gets less if x
 beg9s to develop a wai/1 & great] if x 
beg9s to bulge4 ,let u !re=e try &      
balance "o ) a bulge aga9/ ano!r ) a    
wai/4 ,imm$iately t ,i op5 ! tap & let !
 air pass1 ! "o ) a bulge bl[s air r\nd 
to ! "o ) a wai/ & !y bo? become        
/raight4 ,9 ,fig4 #cb ! direction ( !   
movem5t ( ! air & ( ! sides ( ! bubble  
is indicat$ by arr[s4 ,let u next try ! 
same exp]im5t ) a pair ( r long]        
cyl9d]s1 say ab\t twice z long z !y are 
wide4 ,!y are n[ ready1 "o ) a bulge &  
"o ) a wai/4 ,directly ,i op5 ! tap1 &  
let ! air pass f "o to ! o!r1 ! "o ) a  
wai/ bl[s out ! o!r /ill m 7,fig4 #cc71 
until at la/ x has %ut itself up4 ,x    
!re=e behaves exactly 9 ! opposite way t
 ! %ort cyl9d] did4 ,if y try pairs (   
cyl9d]s ( diff]5t l5g?s y w f9d t !     
*ange occurs :5 !y are j ov] "o & a half
 times z long z !y are wide4 ,n[ if y   
imag9e "o ( ^! tubes jo9$ on to ! end ( 
! o!r1 y w see t a cyl9d] m ?an ab\t    

?ree times z long z x is wide _c la/ m  
?an a mom5t2 because if "o end 7 to     
contract ev] s little ! pressure !re    
w\ld increase1 & ! n>r[ end w\ld bl[ air
 into ! wid] end 7,fig4 #cd71 until !   
sides ( ! n>r[ end met "o ano!r4 ,!     
exact l5g? ( ! longe/ cyl9d] t is /able1
 is a little m ?an ?ree diamet]s4 ,!    
cyl9d] j becomes un/able :5 its l5g? is 
equal to its circumf]5ce1 & ?is is      
#c-a_/g diamet]s almo/ exactly4         
,illu/ration3 ,fig4 #cd4  ,i w gradually
 sep>ate ^! r+s1 keep+ up a supply (    
air1 & y w see t :5 ! tube gets ne>ly   
?ree times z long z x is wide x is gett+
 v difficult to manage1 & !n sudd5ly x  
gr[s a wai/ ne>] "o end ?an ! o!r1 &    
breaks (f =m+ a pair ( sep>ate & unequal
 bubbles4  ,if n[ y h a cyl9d] ( liquid 
( great l5g? sudd5ly =m$ & left to      
itself1 x cle>ly _c reta9 t =m4 ,x mu/  
break up into a s]ies ( drops4          
,un=tunately ! *anges g on s quickly 9 a
 fall+ /ream ( wat] t no "o by m]ely    
look+ at x c\ld foll[ ! movem5ts ( !    

sep>ate drops1 b ,i hope to be able to  
%[ to y 9 two or ?ree ways exactly :at  
is happ5+4 ,y may rememb] t we 7 able to
 make a l>ge drop ( "o liquid 9 ano!r1  
because 9 ?is way ! effect ( ! weight 0 
neutraliz$1 & z l>ge drops oscillate or 
*ange _! %ape mu* m sl[ly ?an small1 x  
is m easy to see :at is happ5+4 ,i h 9  
?is glass box wat] col\r$ blue on :i* is
 float+ p>aff91 made heavi] by mix+ ) x 
a bad-smell+ & dang]\s liquid call$     
bisulphide ( c>bon4  ,sid5ote3 ,see     
,diagram at ! end ( ! ,book4  ,fig4 #ce4
  ,! wat] is only a v little heavi] ?an 
! mixture4 ,if ,i n[ dip a pipe into !  
wat] & let x fill1 ,i c !n raise x &    
all[ drops to sl[ly =m4 ,drops z l>ge z 
a %ill+ are n[ =m+1 & :5 ea* "o has     
rea*$ its full size1 a neck =ms above x1
 :i* is drawn out by ! fall+ drop into a
 little cyl9d]4 ,y w notice t ! liquid (
 ! neck has ga!r$ itself into a little  
drop :i* falls away j aft] ! l>ge drop4 
,! action is n[ go+ on s sl[ly t y c    
foll[ x4 ,fig4 #ce conta9s =ty-?ree     

consecutive views ( ! gr[? & fall ( !   
drop tak5 photographically at int]vals (
 "o-tw5tie? ( a second4 ,= ! use to :i* 
?is figure is to be put1 see page #adi4 
,if ,i aga9 fill ! pipe ) wat]1 & ?is "t
 draw x rapidly out ( ! liquid1 ,i %all 
leave beh9d a cyl9d] :i* w break up into
 balls1 z y c easily see 7,fig4 #cf74 ,i
 %\ld l n[ to %[ y1 z ,i h ?is app>atus 
9 its place1 t y c bl[ bubbles ( wat]   
conta9+ p>aff9 9 ! p>aff9 mixture1 & y w
 see "s :i* h o!r bubbles & drops ( "o  
or o!r liquid inside aga94 ,"o ( ^!     
comp\nd bubble drops is n[ re/+ /ation>y
 on a heavi] lay] ( liquid1 s t y c see 
x all ! bett] 7,fig4 #cg74 ,if ,i       
rapidly draw ! pipe out ( ! box ,i %all 
leave a long cyl9drical bubble ( wat]   
conta9+ p>aff91 & ?is1 z 0 ! case ) !   
wat]-cyl9d]1 sl[ly breaks up into       
sph]ical bubbles4  ,illu/ration3 ,fig4  
#cf4  ,illu/ration3 ,fig4 #cg4          
,illu/ration3 ,fig4 #ch4  ,hav+ n[ %[n t
 a v l>ge liquid cyl9d] breaks up       
regul>ly into drops1 ,i %all next g !   

o!r extreme1 & take z an example an     
excessively f9e cyl9d]4 ,y see a        
photograph ( a spid] on h] geometrical  
web 7,fig4 #ch74 ,if ,i _h "t ,i %\ld l 
to tell y h[ ! spid] goes to "w to make 
?is beautiful /ructure1 & a great deal  
ab\t ^! wond]ful creatures1 b ,i mu/ d  
no m ?an %[ y t !re are two k9ds (      
web--^? t po9t outw>ds1 :i* are h>d &   
smoo?1 & ^? t g r\nd & r\nd1 :i* are v  
ela/ic1 & :i* are cov]$ ) beads ( a     
/icky liquid4 ,n[ !re are 9 a good web  
ov] a qu>t] ( a million ( ^! beads :i*  
cat* ! flies = ! spid]'s d9n]4 ,a spid] 
makes a :ole web 9 an h\r1 & g5]ally has
 to make a new "o e day4 ,%e w\ld n be  
able to g r\nd & /ick all ^! 9 place1   
ev5 if %e knew h[1 because %e w\ld n h  
"t4 ,in/ead ( ?is %e makes use ( ! way t
 a liquid cyl9d] breaks up into beads z 
foll[s4 ,%e sp9s a ?read1 & at ! same "t
 wets x ) a /icky liquid1 :i* ( c\rse is
 at fir/ a cyl9d]4 ,?is _c rema9 a      
cyl9d]1 b breaks up into beads1 z !     
photograph tak5 ) a microscope f a real 

web beautifully %[s 7,fig4 #ci74 ,y see 
! alt]nate l>ge & small drops1 &        
sometimes y ev5 see extra small drops   
betwe5 ^! aga94 ,9 ord] t y may see     
exactly h[ l>ge ^! beads really are1 ,i 
h plac$ alongside a scale ( ?\s&?s ( an 
in*1 :i* 0 photograph$ at ! same "t4 ,to
 prove to y t ?is is :at happ5s1 ,i %all
 n[ %[ y a web t ,i h made myself by    
/rok+ a qu>tz fibre ) a /raw dipp$ 9    
ca/or-oil4 ,! same alt]nate l>ge & small
 beads are aga9 visible j z p]fect z !y 
7 9 ! spid]'s web4 ,9 fact x is         
impossible to di/+ui% betwe5 "o ( my    
bead$ webs & a spid]'s by look+ at !m4  
,& !re is ?is additional simil>ity--my  
webs are j z good z a spid]'s = cat*+   
flies4 ,y might say t a l>ge cyl9d] (   
wat] 9 oil1 or a microscopic cyl9d] on a
 ?read1 is n ! same z an ord9>y jet (   
wat]1 & t y w\ld l to see if x behaves z
 ,i h describ$4 ,! next photograph      
7,fig4 #dj71 tak5 by ! light ( an       
in/antane\s electric sp>k1 & magnifi$   
?ree & a qu>t] times1 %[s a f9e column (

 wat] fall+ f a jet4 ,y w n[ see t x is 
at fir/ a cyl9d]1 t z x goes d[n necks &
 bulges beg9 to =m1 & at la/ beads      
sep>ate1 & y c see ! little drops z     
well4 ,! beads also vibrate1 becom+     
alt]nately long & wide1 & !re c be no   
d\bt t ! sp>kl+ portion ( a jet1 ?\gh x 
appe>s cont9u\s1 is really made up (    
beads :i* pass s rapidly be=e ! eye t x 
is impossible to foll[ !m4 7,i %\ld     
expla9 t = a reason :i* w appe> lat]1 ,i
 made a l\d note by :i/l+ into a key at 
! "t t ?is photograph 0 tak547          
,illu/ration3 ,fig4 #ci4  ,illu/ration3 
,fig4 #dj4  ,"l ,rayleigh has %[n t 9 a 
/ream ( wat] "o tw5ty-fif? ( an in* 9   
diamet]1 necks impress$ ^u ! /ream1 ev5 
?\gh imp]ceptible1 develop a ?\s&fold 9 
dep? e =tie? ( a second1 & ?us x is n   
difficult to und]/& t 9 su* a /ream !   
wat] is already brok5 ?r\gh be=e x has  
fall5 _m in*es4 ,he has also %[n t free 
wat] drops vibrate at a rate :i* may be 
f\nd z foll[s4 ,a drop two in*es 9      
diamet] makes "o complete vibration 9 "o

 second4 ,if ! diamet] is r$uc$ to "o   
qu>t] ( its am\nt1 ! "t ( vibration w be
 r$uc$ to "o-eigh?1 or if ! diamet] is  
r$uc$ to "o-hundr$?1 ! "t w be r$uc$ to 
"o-?\s&?1 & s on4 ,! same relation      
betwe5 ! diamet] & ! "t ( break+ up     
applies also to cyl9d]s4 ,we c at once  
see h[ fa/ a bead ( wat] ! size ( "o (  
^? 9 ! spid]'s web w\ld vibrate if pull$
 out ( %ape1 & let g sudd5ly4 ,if we    
take ! diamet] z be+ "o eight-hundr$? ( 
an in*1 & x is really ev5 f9]1 !n ! bead
 w\ld h a diamet] ( "o sixte5-hundr$? ( 
a two-in* bead1 :i* makes "o vibration 9
 "o second4 ,x w !re=e vibrate sixty-f\r
 ?\s& times z fa/1 or sixty-f\r ?\s&    
times a second4 ,wat]-drops ! size ( !  
little beads1 ) a diamet] ( r less ?an  
"o ?ree-?\s&? ( an in*1 w\ld vibrate    
half a million times a second1 "u ! sole
 influ5ce ( ! feebly ela/ic sk9 ( wat]6 
,we ?us see h[ p[]ful is ! influ5ce ( ! 
feebly ela/ic wat]-sk9 on drops ( wat] t
 are suffici5tly small4  ,i %all n[     
cause a small f\nta9 to play1 & %all    

all[ ! wat] z x falls to patt] ^u a %eet
 ( pap]4 ,y c see bo? ! f\nta9 itself & 
its %ad[ ^u ! scre54 ,y w notice t !    
wat] comes out ( ! nozzle z a smoo?     
cyl9d]1 t x pres5tly beg9s to glitt]1 & 
t ! sep>ate drops scatt] ov] a great    
space 7,fig4 #da74 ,n[ :y %\ld ! drops  
scatt]8 ,all ! wat] comes out ( ! jet at
 ! same rate & />ts 9 ! same direction1 
& yet aft] a %ort way ! sep>ate drops by
 no means foll[ ! same pa?s4 ,n[ in/ead 
( expla9+ ?is1 & !n %[+ exp]im5ts to te/
 ! tru? ( ! explanation1 ,i %all rev]se 
! usual ord]1 & %[ "o or two exp]im5ts  
fir/1 :i* ,i ?9k y w all agree are s l  
magic1 s wond]ful are !y & yet s simple1
 t if !y _h be5 p]=m$ a few hundr$ ye>s 
ago1 ! ra% p]son :o %[$ !m might h run a
 s]i\s risk ( be+ burnt alive4          
,illu/ration3 ,fig4 #da4  ,illu/ration3 
,fig4 #db4  ,y n[ see ! wat] ( ! jet    
scatt]+ 9 all directions1 & y he> x mak+
 a patt]+ s\nd on ! pap] on :i* x falls4
 ,i take out ( my pocket a /ick (       
seal+-wax & in/antly all is *ang$1 ev5  

?\gh ,i am "s way (f & c t\* no?+4 ,!   
wat] ceases to scatt]2 x travels 9 "o   
cont9u\s l9e 7,fig4 #db71 & falls ^u !  
pap] mak+ a l\d rattl+ noise :i* mu/    
rem9d y ( ! ra9 ( a ?und]-/orm4 ,i come 
a little ne>] to ! f\nta9 & ! wat]      
scatt]s aga91 b ?is "t 9 q a diff]5t    
way4 ,! fall+ drops are mu* l>g] ?an !y 
7 be=e4 ,directly ,i hide ! seal+-wax ! 
jet ( wat] recov]s its old appe>ance1 & 
z soon z ! seal+-wax is tak5 out x      
travels 9 a s+le l9e aga94  ,n[ in/ead (
 ! seal+-wax ,i %all take a smoky flame 
easily made by dipp+ "s cotton-wool on !
 end ( a /ick into b5z9e1 & light+ x4 ,z
 long z ! flame is held away f ! f\nta9 
x produces no effect1 b ! in/ant t ,i   
br+ x ne> s t ! wat] passes ?r\gh !     
flame1 ! f\nta9 ceases to scatt]2 x all 
runs 9 "o l9e & falls 9 a dirty black   
/ream ^u ! pap]4 ,ev] s little oil f$   
into ! jet f a tube z f9e z a hair does 
exactly ! same ?+4  ,illu/ration3 ,fig4 
#dc4  ,i %all n[ set a tun+-=k s\nd+ at 
! o!r side ( ! table4 ,! f\nta9 has n   

alt]$ 9 appe>ance4 ,i n[ t\* ! /& ( !   
tun+-=k ) a long /ick :i* re/s aga9/ !  
nozzle4 ,aga9 ! wat] ga!rs itself toge!r
 ev5 m p]fectly ?an be=e1 & ! pap] ^u   
:i* x falls is humm+ out a note :i* is !
 same z t produc$ by ! tun+-=k4 ,if ,i  
alt] ! rate at :i* ! wat] fl[s y w see t
 ! appe>ance is *ang$ aga91 b x is nev] 
l a jet :i* is n act$ ^u by a musical   
s\nd4 ,sometimes ! f\nta9 breaks up into
 two or ?ree & sometimes _m m di/9ct    
l9es1 z ?\gh x came out ( z _m tubes (  
diff]5t sizes & po9t+ 9 slightly diff]5t
 directions 7,fig4 #dc74 ,! effect (    
diff]5t notes c\ld be v easily %[n if   
any "o 7 to s+ to ! piece ( wood by :i* 
! jet is held4 ,i c make noises (       
diff]5t pit*es1 :i* = ?is purpose are   
p]haps bett] ?an musical notes1 & y c   
see t ) e new noise ! f\nta9 puts on a  
diff]5t appe>ance4 ,y may well wond] h[ 
^! trifl+ influ5ces--seal+-wax1 ! smoky 
flame1 or ! m or less musical           
noise--%\ld produce ?is my/]i\s result1 
b ! explanation is n s difficult z y    

might expect4  ,i hope to make ?is cle> 
:5 we meet aga94     ,,lecture ,,iii4   
,at ! conclusion ( ! la/ lecture ,i %[$ 
y "s curi\s exp]im5ts ) a f\nta9 ( wat]1
 :i* ,i h n[ to expla94 ,consid] :at ,i 
h said ab\t a liquid cyl9d]4 ,if x is a 
little m ?an ?ree times z long z x is   
wide1 x _c reta9 its =m2 if x is made v 
mu* m ?an ?ree times z long1 x w break  
up into a s]ies ( beads4 ,n[1 if 9 any  
way a s]ies ( necks c\ld be develop$ ^u 
a cyl9d] :i* 7 less ?an ?ree diamet]s   
ap>t1 "s ( !m w\ld t5d to heal up1      
because a piece ( a cyl9d] less ?an ?ree
 diamet]s long is /able4 ,if !y 7 ab\t  
?ree diamet]s ap>t1 ! =m be+ !n un/able1
 ! necks w\ld get m pron\nc$ 9 "t1 &    
w\ld at la/ break ?r\gh1 s t beads w\ld 
be =m$4 ,if necks 7 made at di/ances m  
?an ?ree diamet]s ap>t1 !n ! cyl9d] w\ld
 g on break+ up by ! n>r[+ ( ^! necks1 &
 x w\ld mo/ easily break up into drops  
:5 ! necks 7 j f\r & a half diamet]s    
ap>t4 ,9 o!r words1 if a f\nta9 7 to    
issue f a nozzle held p]fectly /ill1 !  

wat] w\ld mo/ easily break into beads at
 ! di/ance ( f\r & a half diamet]s ap>t1
 b x w\ld break up into a great] numb]  
clos] toge!r1 or a small] numb] fur!r   
ap>t1 if by slight di/urbances ( ! jet v
 slight wai/s 7 impress$ ^u ! issu+     
cyl9d] ( wat]4 ,:5 y make a f\nta9 play 
f a jet :i* y hold z /ill z possible1   
!re are /ill accid5tal tremors ( all    
k9ds1 :i* impress ^u ! issu+ cyl9d]     
slightly n>r[ & wide places at irregul> 
di/ances1 & s ! cyl9d] breaks up        
irregul>ly into drops ( diff]5t sizes & 
at diff]5t di/ances ap>t4 ,n[ ^! drops1 
z !y are 9 ! act ( sep>at+ f "o ano!r1 &
 are draw+ out ! wai/1 z y h se51 are   
be+ pull$ = ! mom5t t[>ds "o ano!r by ! 
ela/icity ( ! sk9 ( ! wai/2 &1 z !y are 
free 9 ! air to move z !y w1 ?is w cause
 ! h9d] "o to hurry on1 & ! m =w>d "o to
 lag beh9d1 s t unless !y are all       
exactly alike bo? 9 size & di/ance ap>t 
!y w _m ( !m b\nce toge!r be=e long4 ,y 
w\ld expect :5 !y hit "o ano!r aft]w>ds 
t !y w\ld jo91 b ,i %all be able to %[ y

 9 a mom5t t !y d n2 !y act l two       
india-rubb] balls1 & b\nce away aga94   
,n[ x is n difficult to see t if y h a  
s]ies ( drops ( diff]5t sizes & at      
irregul> di/ances b\nc+ aga9/ "o ano!r  
frequ5tly1 !y w t5d to sep>ate & to     
fall1 z we h se51 on all p>ts ( ! pap]  
d[n bel[4 ,:at did ! seal+-wax or !     
smoky flame d8 & :at c ! musical s\nd d 
to /op ?is f happ5+8 ,let me fir/ take !
 seal+-wax4 ,a piece ( seal+-wax rubb$  
on y\r coat is electrifi$1 & w attract  
light bits ( pap] up to x4 ,! seal+-wax 
acts electrically on ! diff]5t          
wat]-drops1 caus+ !m to attract "o      
ano!r1 feebly1 x is true1 b ) suffici5t 
p[] :]e !y meet to make !m break ?r\gh !
 air-film betwe5 !m & jo94 ,to %[ t ?is 
is no fancy1 ,i h n[ 9 front ( ! lant]n 
two f\nta9s ( clean wat] com+ f sep>ate 
bottles1 & y c see t !y b\nce ap>t      
p]fectly 7,fig4 #dd74 ,to %[ t !y d     
really b\nce1 ,i h col\r$ ! wat] 9 ! two
 bottles diff]5tly4 ,! seal+-wax is n[ 9
 my pocket2 ,i %all retire to ! o!r side

 ( ! room1 & ! in/ant x appe>s ! jets ( 
wat] coalesce 7,fig4 #de74 ,?is may be  
repeat$ z (t5 z y l1 & x nev] fails4 ,^!
 two b\nc+ jets are 9 fact "o ( ! mo/   
delicate te/s = ! pres5ce ( electricity 
t exi/4 ,y are n[ able to und]/& ! fir/ 
exp]im5t4 ,! sep>ate drops :i* b\nc$    
away f "o ano!r1 & scatt]$ 9 all        
directions1 are unable to b\nce :5 !    
seal+-wax is held up1 because ( its     
electrical action4 ,!y !re=e unite1 & ! 
result is1 t in/ead ( a great numb] (   
little drops fall+ all ov] ! pap]1 !    
/ream p\rs 9 a s+le l9e1 & great drops1 
su* z y see 9 a ?und]-/orm1 fall on !   
top ( "o ano!r4 ,!re c be no d\bt t x is
 = ?is reason t ! drops ( ra9 9 a       
?und]-/orm are s l>ge4 ,?is exp]im5t &  
its explanation are due to ,"l          
,rayleigh4  ,illu/ration3 ,fig4 #dd4    
,illu/ration3 ,fig4 #de4  ,! smoky      
flame1 z lately %[n by ,mr4 ,bidwell1   
does ! same ?+4 ,! reason probably is t 
! dirt breaks ?r\gh ! air-film1 j z du/ 
9 ! air w make ! two f\nta9s jo9 z !y   

did :5 !y 7 electrifi$4 ,h[ev]1 x is    
possible t oily matt] cond5s$ on ! wat] 
may h some?+ to d ) ! effect obs]v$1    
because oil alone acts q z well z a     
flame1 b ! action ( oil 9 ?is case1 z :5
 x smoo?s a /ormy sea1 is n by any means
 s easily und]/ood4  ,:5 ,i held !      
seal+-wax clos]1 ! drops coalesc$ 9 !   
same way2 b !y 7 !n s mu* m electrifi$ t
 !y repell$ "o ano!r z simil>ly         
electrifi$ bodies are kn[n to d1 & s !  
electrical scatt]+ 0 produc$4  ,y       
possibly already see :y ! tun+-=k made !
 drops foll[ 9 "o l9e1 b ,i %all expla94
 ,a musical note is1 z is well kn[n1    
caus$ by a rapid vibration2 ! m rapid ! 
vibration ! high] is ! pit* ( ! note4 ,=
 in/ance1 ,i h a too?-:eel :i* ,i c turn
 r\nd v rapidly if ,i wi%4 ,n[ t x is   
turn+ sl[ly y c he> ! sep>ate tee?      
knock+ aga9/ a c>d t ,i am hold+ 9 ! o!r
 h&4 ,i am n[ turn+ fa/]1 & ! c>d is    
giv+ out a note ( a l[ pit*4 ,z ,i make 
! :eel turn fa/] & fa/]1 ! pit* ( ! note
 gradually rises1 & x w\ld1 if ,i c\ld  

only turn fa/ en\gh1 give s high a note 
t we %\ld n be able to he> x4 ,a tun+-=k
 vibrates at a c]ta9 def9ite rate1 &    
!re=e gives a def9ite note4 ,! =k n[    
s\nd+ vibrates #abh times 9 e second4 ,!
 nozzle1 !re=e1 is made to vibrate1 b   
almo/ imp]ceptibly1 #abh times a second1
 & to impress ^u ! issu+ cyl9d] ( wat]  
#abh imp]ceptible wai/s e second4 ,n[ x 
j dep5ds :at size ! jet is1 & h[ fa/ !  
wat] is issu+1 :e!r ^! wai/s are ab\t   
f\r & a half diamet]s ap>t 9 ! cyl9d]4  
,if ! jet is l>g]1 ! wat] mu/ pass m    
quickly1 or "u a great] pressure1 = ?is 
to be ! case2 if ! jet is f9]1 a small] 
spe$ w be suffici5t4 ,if x %\ld happ5 t 
! wai/s s made are any:]e ab\t f\r      
diamet]s ap>t1 !n ev5 ?\gh !y are s     
slightly develop$ t if y _h an exact    
draw+ ( !m1 y w\ld n be able to detect !
 slighte/ *ange ( diamet]1 !y w gr[ at a
 great spe$1 & !re=e ! wat] column w    
break up regul>ly1 e drop w be l ! "o   
beh9d x1 & l ! "o 9 front ( x1 & n all  
diff]5t1 z is ! case :5 ! break+ ( !    

wat] m]ely dep5ds ^u accid5tal tremors4 
,if ! drops !n are all alike 9 e        
respect1 ( c\rse !y all foll[ ! same    
pa?1 & s appe> to fall 9 a cont9u\s     
/ream4 ,if ! wai/s are ab\t f\r & a half
 diamet]s ap>t1 !n ! jet w break up mo/ 
easily2 b x w1 z ,i h said1 break up "u 
! influ5ce ( a consid]able range (      
notes1 :i* cause ! wai/s to be =m$ at   
o!r di/ances1 provid$ !y are m ?an ?ree 
diamet]s ap>t4 ,if two notes are s\nd$  
at ! same "t1 !n v (t5 ea* w produce its
 own effect1 & ! result is ! alt]nate   
=mation ( drops ( diff]5t sizes1 :i* !n 
make ! jet divide into two sep>ate      
/reams4 ,9 ?is way1 ?ree1 f\r1 or ev5 _m
 m di/9ct /reams may be produc$4        
,illu/ration3 ,fig4 #df4  ,i c n[ %[ y  
photographs ( "s ( ^! musical f\nta9s1  
tak5 by ! in/antane\s fla% ( an electric
 sp>k1 & y c see ! sep>ate pa?s describ$
 by ! drops ( diff]5t sizes 7,fig4 #df74
 ,9 "o photograph !re are eight di/9ct  
f\nta9s all break+ f ! same jet1 b      
foll[+ q di/9ct pa?s1 ea* ( :i* is      

cle>ly m>k$ out by a p]fectly regul>    
s]ies ( drops4 ,y c also 9 ^!           
photographs see drops actually 9 ! act (
 b\nc+ aga9/ "o ano!r1 & flatt5$ :5 !y  
meet1 z if !y 7 india-rubb] balls4 ,9 ! 
photograph n[ ^u ! scre5 ! effect ( ?is 
reb\nd1 :i* occurs at ! place m>k$ ) a  
cross1 is to hurry on ! upp] & m =w>d   
drop1 & to ret>d ! o!r "o1 & s to make  
!m travel ) slightly diff]5t velocities 
& directions4 ,x is = ?is reason t !y   
aft]w>ds foll[ di/9ct pa?s4 ,! small]   
drops _h no d\bt be5 act$ on 9 a simil> 
way1 b ! "p ( ! f\nta9 :]e ?is happ5$ 0 
j outside ! photographic plate1 & s !re 
is no record ( :at occurr$4 ,! v little 
drops ( :i* ,i h s (t5 spok5 are g5]ally
 ?r[n out f ! side ( a f\nta9 ( wat] "u 
! influ5ce ( a musical s\nd1 aft] :i* !y
 describe regul> little curves ( _! own1
 q di/9ct f ! ma9 /ream4 ,!y1 ( c\rse1 c
 only get out sideways aft] "o or two   
b\nc+s f ! regul> drops 9 front & beh9d4
 ,y c easily %[ t !y are really =m$ bel[
 ! place :]e !y fir/ appe>1 by tak+ a   

piece ( electrifi$ seal+-wax & hold+ x  
ne> ! /ream close to ! nozzle &         
gradually rais+ x4 ,:5 x comes opposite 
to ! place :]e ! little drops are really
 =m$1 x w act on !m m p[]fully ?an on ! 
l>ge drops1 & imm$iately pull !m out f a
 place :]e ! mom5t be=e none seem$ to   
exi/4 ,!y w !n circulate 9 p]fect little
 orbits r\nd ! seal+-wax1 j z ! planets 
d r\nd ! sun2 b 9 ?is case1 be+ met by !
 resi/ance ( ! air1 ! orbits are        
spirals1 & ! little drops aft] _m       
revolutions ultimately fall ^u ! wax1 j 
z ! planets w\ld fall into ! sun aft] _m
 revolutions1 if _! motion ?r\gh space 7
 int]f]$ ) by friction ( any k9d4  ,!re 
is only "o ?+ ne$$ to make !            
demon/ration ( ! behavi\r ( a musical   
jet complete1 & t is1 t y %\ld y\rselves
 see ^! drops 9 _! diff]5t positions 9  
an actual f\nta9 ( wat]4 ,n[ if ,i 7 to 
produce a p[]ful electric sp>k1 !n x is 
true t "s ( y might = an in/ant cat*    
sight ( ! drops1 b ,i d n ?9k t mo/ w\ld
 see any?+ at all4 ,b if1 in/ead ( mak+ 

m]ely "o fla%1 ,i 7 to make ano!r :5 ea*
 drop _h j travell$ to ! position :i* ! 
"o 9 front ( x occupi$ be=e1 & !n ano!r 
:5 ea* drop _h mov$ on "o place aga91 & 
s on1 !n all ! drops1 at ! mom5ts t !   
fla%es ( light fell ^u !m1 w\ld occupy !
 same positions1 & ?us all ^! drops w\ld
 appe> fix$ 9 ! air1 ?\gh ( c\rse !y    
really are travell+ fa/ en\gh4 ,if1     
h[ev]1 ,i d n q succe$ 9 keep+ exact "t 
) my fla%es ( light1 !n a curi\s        
appe>ance w be produc$4 ,suppose1 =     
in/ance1 t ! fla%es ( light foll[ "o    
ano!r r too quickly1 !n ea* drop w n h  
_h q "t en\gh to get to its prop] place 
at ea* fla%1 & ?us at ! second fla% all 
! drops w be se5 9 positions :i* are j  
beh9d ^? :i* !y occupi$ at ! fir/ fla%1 
& 9 ! same way at ! ?ird fla% !y w be   
se5 /ill fur!r beh9d _! =m] places1 & s 
on1 & !re=e !y w appe> to be mov+ sl[ly 
backw>ds2 :]eas if my fla%es d n foll[ q
 quickly en\gh1 !n ! drops w1 e "t t !re
 is a fla%1 h travell$ j a little too   
f>1 & s !y w all appe> to be mov+ sl[ly 

=w>ds4 ,n[ let u try ! exp]im5t4 ,!re is
 ! electric lant]n s5d+ a p[]ful beam ( 
light on to ! scre54 ,?is ,i br+ to a   
focus ) a l5s1 & !n let x pass ?r\gh a  
small hole 9 a piece ( c>d4 ,! light !n 
spreads out & falls ^u ! scre54 ,!      
f\nta9 ( wat] is betwe5 ! c>d & ! scre51
 & s a %ad[ is ca/ :i* is conspicu\s    
en\gh4 ,n[ ,i place j beh9d ! c>d a     
little electric motor1 :i* w make a disc
 ( c>d :i* has six holes ne> ! edge sp9 
r\nd v fa/4 ,! holes come "o aft] ! o!r 
opposite ! hole 9 ! fix$ c>d1 & s at e  
turn six fla%es ( light are produc$4 ,:5
 ! c>d is turn+ ab\t #ba-a_/b times a   
second1 !n ! fla%es w foll[ "o ano!r at 
! "r rate4 ,i h n[ />t$ ! motor1 & aft] 
a mom5t or two ,i %all h obta9$ ! "r    
spe$1 & ?is ,i "k by bl[+ ?r\gh ! holes1
 :5 a musical note w be produc$1 high]  
?an ! =k if ! spe$ is too high1 & l[]   
?an ! =k if ! spe$ is too l[1 & exactly 
! same z ! =k if x is "r4  ,to make x   
/ill m evid5t :5 ! spe$ is exactly "r1  
,i h plac$ ! tun+-=k also betwe5 ! light

 & ! scre51 s t y may see x illum9at$1 &
 its %ad[ ^u ! scre54 ,i h n yet all[$ !
 wat] to fl[1 b ,i want y to look at !  
=k4 ,= a mom5t ,i h /opp$ ! motor1 s t !
 light may be /eady1 & y c see t ! =k is
 9 motion because its legs appe> blurr$ 
at ! ends1 :]e ( c\rse ! motion is mo/  
rapid4 ,n[ ! motor is />t$1 & almo/ at  
once ! =k appe>s q diff]5t4 ,x n[ looks 
l a piece ( india-rubb]1 sl[ly op5+ &   
%utt+1 & n[ x appe>s q /ill1 b ! noise x
 is mak+ %[s t x is n /ill by any means4
 ,! legs ( ! =k are vibrat+1 b ! light  
only falls ^u !m at regul> int]vals1 :i*
 correspond ) _! movem5t1 & s1 z ,i     
expla9$ 9 ! case ( ! wat]-drops1 ! =k   
appe>s p]fectly /ill4 ,n[ ! spe$ is     
slightly alt]$1 &1 z ,i h expla9$1 ea*  
new fla% ( light1 com+ j too soon or j  
too late1 %[s ! =k 9 a position :i* is j
 be=e or j beh9d t made visible by !    
previ\s fla%4 ,y ?us see ! =k sl[ly go+ 
?r\gh its evolutions1 ?\gh ( c\rse 9    
reality ! legs are mov+ backw>ds & =w>ds
 #abh times a second4 ,by look+ at ! =k 

or its %ad[1 y w !re=e be able to tell  
:e!r ! light is keep+ exact "t ) !      
vibrations1 & !re=e ) ! wat]-drops4  ,n[
 ! wat] is runn+1 & y see all ! sep>ate 
drops app>5tly /ation>y1 /rung l pe>ls  
or beads ( silv] ^u an invisible wire   
7see ,frontispiece74 ,if ,i make ! c>d  
turn ev] s little m sl[ly1 !n all !     
drops w appe> to sl[ly m>* onw>ds1 & :at
 is s beautiful1--b ,i am afraid few w  
see ?is1--ea* little drop may be se5 to 
gradually break (f1 pull+ out a wai/ :i*
 becomes a little drop1 & !n :5 ! ma9   
drop is free x sl[ly oscillates1 becom+ 
wide & long1 or turn+ ov] & ov]1 z x    
goes on its way4 ,if x s happ5s t a     
d\ble or multiple jet is be+ produc$1 !n
 y c see ! little drops mov+ up to "o   
ano!r1 squeez+ ea* o!r :]e !y meet &    
b\nc+ away aga94 ,n[ ! c>d is turn+ a   
little too fa/ & ! drops appe> to be    
mov+ backw>ds1 s t x seems z if ! wat]  
is com+ up out ( ! tank on ! floor1     
quietly go+ ov] my head1 d[n into !     
nozzle1 & s back to ! wat]-supply ( !   

place4 ,( c\rse ?is is n happ5+ at all1 
z y "k v well1 & z y w see if ,i simply 
try & place my f+] betwe5 two ( ^!      
drops4 ,! spla%+ ( ! wat] 9 all         
directions %[s t x is n mov+ q s quietly
 z x appe>s4 ,!re is "o m ?+ t ,i w\ld  
m5tion ab\t ?is exp]im5t4 ,e "t t !     
fla%+ light ga9s or loses "o complete   
fla%1 ^u ! motion ( ! tun+-=k1 x w appe>
 to make "o complete oscillation1 & !   
wat]-drops w appe> to move back or on "o
 place4  ,i mu/ n[ come to "o ( ! mo/   
beautiful applications ( ^! musical jets
 to practical purposes :i* x is possible
 to imag9e1 & :at ,i %all n[ %[ are a   
few out ( a great numb] ( ! exp]im5ts ( 
,mr4 ,*i*e/] ,bell1 c\s9 ( ,mr4 ,graham 
,bell1 ! inv5tor ( ! telephone4  ,to    
beg9 ) ,i h a v small jet ( wat] =c$    
?r\gh ! nozzle at a great pressure1 z y 
c see if ,i po9t x t[>ds ! ceil+1 z !   
wat] rises eight or t5 feet4 ,if ,i all[
 ?is /ream ( wat] to fall ^u an         
india-rubb] %eet1 /ret*$ ov] ! end ( a  
tube z big z my little f+]1 !n ! little 

%eet w be depress$ by ! wat]1 & ! m s if
 ! /ream is /rong4 ,n[ if ,i hold ! jet 
close to ! %eet ! smoo? column ( liquid 
w press ! %eet /eadily1 & x w rema9     
quiet2 b if ,i gradually take ! jet     
fur!r away f ! %eet1 !n any wai/s t may 
h be5 =m$ 9 ! liquid column1 :i* gr[ z  
!y travel1 w make _! exi/5ce p]fectly   
evid5t4 ,:5 a wide "p ( ! column /rikes 
! %eet x w be depress$ r m ?an usual1 & 
:5 a n>r[ "p foll[s1 ! depression w be  
less4 ,9 o!r words1 any v slight        
vibration imp>t$ to ! jet w be magnifi$ 
by ! gr[? ( wai/s1 & ! %eet (           
india-rubb] w reproduce ! vibration1 b  
on a magnifi$ scale4 ,n[ if y rememb] t 
s\nd consi/s ( vibrations1 !n y w und]/&
 t a jet is a ma*9e = magnify+ s\nd4 ,to
 %[ t ?is is ! case ,i am n[ direct+ !  
jet on to ! %eet1 & y c he> no?+2 b ,i  
%all hold a piece ( wood aga9/ ! nozzle1
 & n[1 if on ! :ole ! jet t5ds to break 
up at any "o rate r ?an at any o!r1 or  
if ! wood or ! %eet ( rubb] w vibrate at
 any rate mo/ easily1 !n ! fir/ few     

vibrations :i* correspond to ?is rate w 
be imp>t$ to ! wood1 :i* w impress !m ^u
 ! nozzle & s ^u ! cyl9d] ( liquid1 :]e 
!y w become magnifi$2 ! result is t !   
jet imm$iately beg9s to s+ ( its own    
accord1 giv+ out a l\d note 7,fig4 #dg74
  ,i w n[ remove ! piece ( wood4 ,on    
plac+ aga9/ ! nozzle an ord9>y lev]     
wat*1 ! jolt :i* is imp>t$ to ! case at 
e tick1 ?\gh x is s small t y _c detect 
x1 jolts ! nozzle also1 & ?us causes a  
neck to =m 9 ! jet ( wat] :i* w gr[ z x 
travels1 & s produce a l\d tick1 audible
 9 e "p ( ?is l>ge room 7,fig4 #dh74 ,n[
 ,i want y to notice h[ ! vibration is  
magnifi$ by ! action ,i h describ$4 ,i  
n[ hold ! nozzle close to ! rubb] %eet1 
& y c he> no?+4 ,z ,i gradually raise x 
a fa9t e*o is produc$1 :i* gradually    
gets l\d] & l\d]1 until at la/ x is m l 
a hamm] /rik+ an anvil ?an ! tick ( a   
wat*4  ,illu/ration3 ,fig4 #dg4         
,illu/ration3 ,fig4 #dh4  ,i %all n[    
*ange ?is wat* = ano!r :i*1 ?anks to a  
fri5d1 ,i am able to use4 ,?is wat* is a

 repeat]1 t is1 if y press ^u a nob x w 
/rike1 fir/ ! h\r1 !n ! qu>t]s1 & !n !  
m9utes4 ,i ?9k ! wat]-jet w enable y all
 to he> :at "t x is4 ,li/56 "o1 two1    
?ree1 f\r2444 t+-tang1 t+-tang2444 "o1  
two1 ?ree1 f\r1 five1 six4 ,six m9utes  
aft] half-pa/ f\r4 ,y notice t n only   
did y he> ! numb] ( /rokes1 b ! jet     
fai?fully reproduc$ ! musical notes1 s t
 y c\ld di/+ui% "o note f ! o!rs4  ,i c 
9 ! same way make ! jet play a tune by  
simply mak+ ! nozzle re/ aga9/ a long   
/ick1 :i* is press$ ^u a musical-box4 ,!
 musical-box is c>efully %ut up 9 a     
d\ble box ( ?ick felt1 & y c h>dly he>  
any?+2 b ! mom5t t ! nozzle is made to  
re/ aga9/ ! /ick & ! wat] is direct$ ^u 
! india-rubb] %eet1 ! s\nd ( ! box is   
l\dly he>d1 ,i hope1 9 e "p ( ! room4 ,x
 is usual to describe a f\nta9 z play+1 
b x is n[ evid5t t a f\nta9 c ev5 play a
 tune4 ,!re is1 h[ev]1 "o peculi>ity :i*
 is p]fectly evid5t4 ,! jet breaks up at
 c]ta9 rates m easily ?an at o!rs1 or1 9
 o!r words1 x w respond to c]ta9 s\nds 9

 pref]5ce to o!rs4 ,y c he> t z !       
musical-box plays1 c]ta9 notes are      
emphasiz$ 9 a curi\s way1 produc+ mu* ! 
same effect t foll[s if y lay a p5ny ^u 
! upp] /r+s ( a horizontal piano4       
,illu/ration3 ,fig4 #di4  ,n[1 on       
return+ to our soap-bubbles1 y may      
rememb] t ,i /at$ t ! cat5oid & ! plane 
7 ! only figures ( revolution :i* _h no 
curvature1 & :i* !re=e produc$ no       
pressure4 ,!re are pl5ty ( o!r surfaces 
:i* are app>5tly curv$ 9 all directions 
& yet h no curvature1 & :i* !re=e       
produce no pressure2 b ^! are n figures 
( revolution1 t is1 !y _c be obta9$ by  
simply sp9n+ a curv$ l9e ab\t an axis4  
,^! may be produc$ 9 any quantity by    
mak+ wire frames ( v>i\s %apes & dipp+  
!m 9 soap & wat]4 ,on tak+ !m out a     
wond]ful v>iety ( surfaces ( no         
curvature w be se54 ,"o su* surface is t
 kn[n z ! screw-surface4 ,to produce ?is
 x is only necess>y to take a piece (   
wire w\nd a few times 9 an op5 helix    
7commonly call$ spiral71 & to b5d ! two 

ends s z to meet a second wire pass+ d[n
 ! c5tre4 ,! screw-surface develop$ by  
dipp+ ?is frame 9 soap-wat] is well wor?
 see+ 7,fig4 #di74 ,x is impossible to  
give any idea ( ! p]fection ( ! =m 9 a  
figure1 b =tunately ?is is an exp]im5t  
:i* any "o c easily p]=m4  ,illu/ration3
 ,fig4 #ej4  ,!n aga91 if a wire frame  
is made 9 ! %ape ( ! edges ( any ( !    
regul> geometrical solids1 v beautiful  
figures w be f\nd ^u !m aft] !y h be5   
dipp$ 9 soap-wat]4 ,9 ! case ( !        
triangul> prism ^! surfaces are all     
flat1 & at ! edges :]e ^! planes meet "o
 ano!r !re are always ?ree meet+ ea* o!r
 at equal angles 7,fig4 #ej74 ,?is1 ow+ 
to ! fact t ! frame is ?ree-sid$1 is n  
surpris+4 ,aft] look+ at ?is ?ree-sid$  
frame ) ?ree films meet+ d[n ! c5tral   
l9e1 y might expect t ) a f\r-sid$ or   
squ>e frame !re w\ld be f\r films meet+ 
ea* o!r 9 a l9e d[n ! middle4 ,b x is a 
curi\s ?+ t x does n matt] h[ irregul> !
 frame may be1 or h[ complicat$ a mass (
 fro? may be1 !re c nev] be m ?an ?ree  

films meet+ 9 an edge1 or m ?an f\r     
edges1 or six films1 meet+ 9 a po9t4    
,moreov] ! films & edges c only meet "o 
ano!r at equal angles4 ,if = a mom5t by 
any accid5t f\r films d meet 9 ! same   
edge1 or if ! angles are n exactly      
equal1 !n ! =m1 :atev] x may be1 is     
un/able2 x _c la/1 b ! films slide ov]  
"o ano!r & nev] re/ until !y h settl$   
d[n into a position 9 :i* ! conditions (
 /ability are fulfill$4 ,?is may be     
illu/rat$ by a v simple exp]im5t :i* y c
 easily try at home1 & :i* y c n[ see   
project$ ^u ! scre54 ,!re are two pieces
 ( w9d[-glass ab\t half an in* ap>t1 :i*
 =m ! sides ( a sort ( box into :i* "s  
soap & wat] h be5 p\r$4 ,on bl[+ ?r\gh a
 pipe :i* is imm]s$ 9 ! wat]1 a great   
numb] ( bubbles are =m$ betwe5 ! plates4
 ,if ! bubbles are all l>ge en\gh to    
rea* across f "o plate to ! o!r1 y w at 
once see t !re are n[h]e m ?an ?ree     
films meet+ "o ano!r1 & :]e !y meet !   
angles are all equal4 ,! curvature ( !  
bubbles makes x difficult to see at fir/

 t ! angles really are all alike1 b if y
 only look at a v %ort piece close to   
:]e !y meet1 & s avoid be+ bewild]$ by !
 curvature1 y w see t :at ,i h said is  
true4 ,y w also see1 if y are quick1 t  
:5 ! bubbles are bl[n1 sometimes f\r = a
 mom5t d meet1 b t !n ! films at once   
slide ov] "o ano!r & settle d[n into _! 
only possible position ( re/ 7,fig4     
#ea74  ,! air inside a bubble is g5]ally
 "u pressure1 :i* is produc$ by its     
ela/icity & curvature4 ,if ! bubble w\ld
 let ! air pass ?r\gh x f "o side to !  
o!r ( c\rse x w\ld soon %ut up1 z x did 
:5 a r+ 0 hung ^u "o1 & ! film )9 ! r+ 0
 brok54 ,b !re are no holes 9 a bubble1 
& s y w\ld expect t a gas l air c\ld n  
pass ?r\gh to ! o!r side4 ,nev]!less x  
is a fact t gases c sl[ly get ?r\gh to !
 o!r side1 & 9 ! case ( c]ta9 vap\rs !  
process is f> m rapid ?an any "o w\ld   
?9k possible4  ,illu/ration3 ,fig4 #ea4 
,illu/ration3 ,fig4 #eb4  ,e!r produces 
a vap\r :i* is v heavy1 & :i* also burns
 v easily4 ,?is vap\r c get to ! o!r    

side ( a bubble almo/ at once4 ,i %all  
p\r a little e!r ^u blott+-pap] 9 ?is   
bell j>1 & fill ! j> ) its heavy vap\r4 
,y c see t ! j> is fill$ ) some?+1 n by 
look+ at x1 = x appe>s empty1 b by look+
 at its %ad[ on ! scre54 ,n[ ,i tilt x  
g5tly to "o side1 & y see some?+ p\r+   
out ( x1 :i* is ! vap\r ( e!r4 ,x is    
easy to %[ t ?is is heavy2 x is only    
necess>y to drop into ! j> a bubble1 & s
 soon z ! bubble meets ! heavy vap\r x  
/ops fall+ & rema9s float+ ^u ! surface 
z a cork does ^u wat] 7,fig4 #eb74 ,n[  
let me te/ ! bubble & see :e!r any ( !  
vap\r has pass$ to ! inside4 ,i pick x  
up out ( ! j> ) a wire r+ & c>ry x to a 
light1 & at once !re is a bur/ ( flame4 
,b ?is is n suffici5t to %[ t ! e!r     
vap\r has pass$ to ! inside1 because x  
might h cond5s$ 9 suffici5t quantity ^u 
! bubble to make x inflammable4 ,y      
rememb] t :5 ,i p\r$ "s ( ?is vap\r ^u  
wat] 9 ! fir/ lecture1 suffici5t cond5s$
 to s weak5 ! wat]-sk9 t ! frame ( wire 
c\ld get ?r\gh to ! o!r side4 ,h[ev]1 ,i

 c see :e!r ?is is ! true explanation or
 n by bl[+ a bubble on a wide pipe1 &   
hold+ x 9 ! vap\r = a mom5t4 ,n[ on     
remov+ x y notice t ! bubble hangs l a  
heavy drop2 x has lo/ ! p]fect r\ndness 
t x _h at fir/1 & ?is looks z if ! vap\r
 _h f\nd its way 91 b ?is is made c]ta9 
by br++ a light to ! m\? ( ! tube1 :5 ! 
vap\r1 =c$ out by ! ela/icity ( !       
bubble1 cat*es fire & burns ) a flame   
five or six in*es long 7,fig4 #ec74 ,y  
might also h notic$ t :5 ! bubble 0     
remov$1 ! vap\r inside x began to pass  
out aga9 & fell away 9 a heavy /ream1 b 
?is y c\ld only see by look+ at ! %ad[  
^u ! scre54  ,illu/ration3 ,fig4 #ec  ,y
 may h notic$ :5 ,i made ! drops ( oil 9
 ! mixture ( alcohol & wat]1 t :5 !y 7  
br\ght toge!r !y did n at once unite2 !y
 press$ aga9/ "o ano!r & pu%$ ea* o!r   
away if all[$1 j z ! wat]-drops did 9 ! 
f\nta9 ( :i* ,i %[$ y a photograph4 ,y  
also may h notic$ t ! drops ( wat] 9 !  
p>aff9 mixture b\nc$ aga9/ "o ano!r1 or 
if fill$ ) ! p>aff91 =m$ bubbles 9 :i*  

(t5 o!r small drops1 bo? ( wat] &       
p>aff91 rema9$ float+4  ,9 all ^! cases 
!re 0 a ?9 film ( some?+ betwe5 ! drops 
:i* !y 7 unable to squeeze out1 namely1 
wat]1 p>aff91 or air1 z ! case might be4
 ,w two soap-bubbles also :5 knock$     
toge!r be unable to squeeze out ! air   
betwe5 !m8 ,?is y c try at home j z well
 z ,i c "h1 b ,i w p]=m ! exp]im5t at   
once4 ,i h bl[n a pair ( bubbles1 & n[  
:5 ,i hit !m toge!r !y rema9 di/9ct &   
sep>ate 7,fig4 #ed74  ,illu/ration3     
,fig4 #ed4  ,i %all next place a bubble 
on a r+1 :i* x is j too l>ge to get     
?r\gh4 ,9 my h& ,i hold a r+1 on :i* ,i 
h a flat film1 made by plac+ a bubble ^u
 x & break+ x on "o side4 ,if ,i g5tly  
press ! bubble ) ! flat film1 ,i c pu% x
 ?r\gh ! r+ to ! o!r side 7,fig4 #ee71 &
 yet ! two h n really t\*$ "o ano!r at  
all4 ,! bubble c be pu%$ backw>ds &     
=w>ds 9 ?is way _m times4  ,illu/ration3
 ,fig4 #ee4  ,i h n[ bl[n a bubble &    
hung x bel[ a r+4 ,to ?is bubble ,i c   
hang ano!r r+ ( ?9 wire1 :i* pulls x a  

little out ( %ape4 ,s9ce ! pressure     
inside is less ?an t correspond+ to a   
complete sph]e1 & s9ce x is great] ?an t
 outside1 & ?is we c tell by look+ at ! 
caps1 ! curve is "p ( "o ( ^? repres5t$ 
by ! dott$ l9es 9 ,c or ,e1 ,fig4 #ca4  
,h[ev]1 )\t consid]+ ! curve any m1 ,i  
%all pu% ! end ( ! pipe inside1 & bl[   
ano!r bubble !re1 & let x g4 ,x falls   
g5tly until x re/s ^u ! out] bubble2 n  
at ! bottom1 because ! heavy r+ keeps t 
"p out ( rea*1 b along a circul> l9e    
high] up 7,fig4 #ef74 ,i c n[ dra9 away 
! heavy drops ( liquid f bel[ ! bubbles 
) a pipe1 & leave !m clean & smoo? all  
ov]4 ,i c n[ pull ! l[] r+ d[n1 squeez+ 
! inn] bubble into a %ape l an egg      
7,fig4 #eg71 or sw+ x r\nd & r\nd1 & !n 
) a little c>e peel away ! r+ f (f !    
bubble1 & leave !m bo? p]fectly r\nd e  
way 7,fig4 #eh74 ,i c draw out ! air f !
 out] bubble till y c h>dly see betwe5  
!m1 & !n bl[ 91 & ! h>d] ,i bl[1 ! m is 
x evid5t t ! two bubbles are n t\*+ at  
all2 ! inn] "o is n[ sp9n+ r\nd & r\nd 9

 ! v c5tre ( ! l>ge bubble1 & f9ally1 on
 break+ ! out] "o ! inn] floats away1   
none ! worse = its v unusual treatm5t4  
,illu/ration3 ,fig4 #ef4  ,illu/ration3 
,fig4 #eg4  ,illu/ration3 ,fig4 #eh4    
,!re is a pretty v>iation ( ! la/       
exp]im5t1 :i*1 h[ev]1 requires t a      
little gre5 dye call$ fluoresc9e1 or    
bett]1 uran9e1 %\ld be dissolv$ 9 a     
sep>ate di% ( ! soap-wat]4 ,!n y c bl[ !
 out] bubble ) clean soap-wat]1 & ! inn]
 "o ) ! col\r$ wat]4 ,!n if y look at ! 
two bubbles by ord9>y light1 y w h>dly  
notice any diff]5ce2 b if y all[        
sunlight1 or electric light f an arc    
lamp1 to %9e ^u !m1 ! inn] "o w appe> a 
brilliant gre51 :ile ! out] "o w rema9  
cle> z be=e4 ,!y w n mix at all1 %[+ t  
?\gh ! inn] "o is app>5tly re/+ aga9/ ! 
out] "o1 !re is 9 reality a ?9 cu%ion ( 
air betwe54  ,n[ y "k t coal-gas is     
light] ?an air1 & s a soap-bubble bl[n )
 gas1 :5 let g1 floats up to ! ceil+ at 
once4 ,i %all bl[ a bubble on a r+ )    
coal-gas4 ,x is soon evid5t t x is pull+

 upw>ds4 ,i %all g on fe$+ x ) gas1 & ,i
 want y to notice ! v beautiful %apes t 
x takes 7,fig4 #ei1 b imag9e ! globe    
inside remov$74 ,^! are all exactly !   
curves t a wat]-drop assumes :5 hang+ f 
a pipe1 except t !y are ! o!r way up4 ,!
 /r5g? ( ! sk9 is n[ b>ely able to )/& !
 pull1 & n[ ! bubble breaks away j z !  
drop ( wat] did4  ,illu/ration3 ,fig4   
#ei4  ,i %all next place a bubble bl[n )
 air ^u a r+1 & bl[ inside x a bubble   
bl[n ) a mixture ( air & gas4 ,x ( c\rse
 floats up & re/s aga9/ ! top ( ! out]  
bubble 7,fig4 #fj74 ,n[ ,i %all let a   
little gas into ! out] "o1 until !      
surr\nd+ gas is ab\t z heavy z ! inn]   
bubble4 ,x n[ no long] re/s aga9/ ! top1
 b floats ab\t 9 ! c5tre ( ! l>ge bubble
 7,fig4 #fa71 j z ! drop ( oil did 9 !  
mixture ( alcohol & wat]4 ,y c see t !  
inn] bubble is really light] ?an air1   
because if ,i break ! out] "o1 ! inn] "o
 rises rapidly to ! ceil+4              
,illu/ration3 ,fig4 #fj4  ,in/ead ( bl[+
 ! fir/ bubble on a heavy fix$ r+1 ,i   

%all n[ bl[ "o on a light r+1 made ( v  
?9 wire4 ,?is bubble conta9s only air4  
,if ,i bl[ inside ?is a bubble )        
coal-gas1 !n ! gas-bubble w try & rise1 
& w press aga9/ ! top ( ! out] "o ) su* 
=ce z to make x c>ry up ! wire r+ & a   
y>d ( cotton1 & "s pap] to :i* ! cotton 
is ti$ 7,fig4 #fb72 & all ?is "t1 ?\gh x
 is ! inn] "o only :i* t5ds to rise1 !  
two bubbles are n really t\*+ "o ano!r  
at all4  ,illu/ration3 ,fig4 #fa4       
,illu/ration3 ,fig4 #fb4  ,i h n[ bl[n  
an air-bubble on ! fix$ r+1 & pu%$ up   
inside x a wire ) a r+ on ! end4 ,i %all
 n[ bl[ ano!r air-bubble on ?is inn] r+4
 ,! next bubble t ,i %all bl[ is "o     
conta9+ gas1 & ?is is inside ! o!r two1 
& :5 let g x re/s aga9/ ! top ( ! second
 bubble4 ,i next make ! second bubble a 
little light] by bl[+ a little gas into 
x1 & !n make ! out] "o l>g] ) air4 ,i c 
n[ peel (f ! inn] r+ & take x away1     
leav+ ! two inn] bubbles free1 inside ! 
out] "o 7,fig4 #fc74 ,& n[ ! multiple   
reflections ( ! brilliant col\rs ( !    

diff]5t bubbles f "o to ! o!r1 set (f by
 ! beautiful =ms :i* ! bubbles !mselves 
assume1 give to ! :ole a degree (       
symmetry & spl5d\r :i* y may g f> to see
 equall$ 9 any o!r way4 ,i h only to bl[
 a f\r? bubble 9 real contact ) ! out]  
bubble & ! r+1 to enable x to peel (f & 
float away ) ! o!r two inside4          
,illu/ration3 ,fig4 #fc4  ,we h se5 t   
bubbles & drops behave 9 v mu* ! same   
way4 ,let u see if electricity w produce
 ! same effect t x did on drops4 ,y     
rememb] t a piece ( electrifi$ seal+-wax
 prev5t$ a f\nta9 ( wat] f scatt]+1     
because :]e two drops met1 in/ead (     
b\nc+1 !y jo9$ toge!r4 ,n[ !re are on ^!
 two r+s bubbles :i* are j re/+ aga9/ "o
 ano!r1 b n really t\*+ 7,fig4 #fd74 ,! 
in/ant t ,i take out ! seal+-wax y see  
!y jo9 toge!r & become "o 7,fig4 #fe74  
,two soap-bubbles1 !re=e1 enable u to   
detect electricity1 ev5 :5 pres5t 9     
m9ute quantity1 j z two wat] f\nta9s    
did4  ,illu/ration3 ,fig4 #fd4          
,illu/ration3 ,fig4 #fe4  ,we c use a   

pair ( bubbles to prove ! tru? ( "o ( ! 
well-kn[n actions ( electricity4 ,inside
 an electrical conductor x is impossible
 to feel any influ5ce ( electricity     
outside1 h[ev] mu* !re may be1 or h[ev] 
ne> y g to ! surface4 ,let u1 !re=e1    
take ! two bubbles %[n 9 ,fig4 #ef1 &   
br+ an electrifi$ /ick ( seal+-wax ne>4 
,! out] bubble is a conductor2 !re is1  
!re=e1 no electrical action inside1 &   
?is y c see because1 ?\gh ! seal+-wax is
 s ne> ! bubble t x pulls x all to "o   
side1 & ?\gh ! inn] "o is s close to !  
out] "o t y _c see betwe5 !m1 yet ! two 
bubbles rema9 sep>ate4 ,_h !re be5 !    
slighte/ electrical influ5ce inside1 ev5
 to a dep? ( a hundr$-?\s&? ( an in*1 ! 
two bubbles w\ld h in/antly come toge!r4
  ,illu/ration3 ,fig4 #ff4  ,!re is "o m
 exp]im5t :i* ,i mu/ %[1 & ?is w be !   
la/2 x is a comb9ation ( ! la/ two1 & x 
beautifully %[s ! diff]5ce betwe5 an    
inside & an outside bubble4 ,i h n[ a   
pla9 bubble re/+ aga9/ ! side ( ! pair t
 ,i h j be5 us+4 ,! in/ant t ,i take out

 ! seal+-wax ! two out] bubbles jo91    
:ile ! inn] "o unh>m$ & ! heavy r+ slide
 d[n to ! bottom ( ! n[ s+le out] bubble
 7,fig4 #ff74  ,& n[ t our "t has drawn 
to a close ,i mu/ ask y :e!r t          
admiration & wond] :i* we all feel :5 we
 play ) soap-bubbles has be5 de/roy$ by 
^! lectures2 or :e!r n[ t y "k m ab\t !m
 x is n increas$4 ,i hope y w all agree 
) me t ! actions ^u :i* su* common &    
e-day ph5om5a z drops & bubbles dep5d1  
actions :i* h occupi$ ! att5tion ( !    
greate/ philosoph]s f ! "t ( ,newton to 
! pres5t day1 are n s trivial z to be   
unwor?y ( ! att5tion ( ord9>y p l       
ourselves4     ,,practical ,,h9ts4   ,i 
hope t ! foll[+ practical h9ts may be   
f\nd useful by ^? :o wi% !mselves to    
successfully p]=m ! exp]im5ts already   
describ$4   ,drop ) ,india-rubb]        
,surface4  ,a %eet ( ?9 india-rubb]1    
ab\t ! ?ickness ( t us$ 9 air-balls1 z x
 appe>s be=e !y h be5 bl[n out1 mu/ be  
/ret*$ ov] a r+ ( wood or metal eighte5 
in*es 9 diamet]1 & securely wir$ r\nd ! 

edge4 ,! wire w hold ! india-rubb] bett]
 if ! edge is groov$4 ,?is does n succe$
 if tri$ on a small] scale4 ,?is        
exp]im5t 0 %[n by ,sir ,w4 ,?omson at ! 
,royal ,in/itution4   ,jump+ ,frame4    
,?is is easily made by tak+ a light     
glass globe ab\t two in*es 9 diamet]1   
su*1 = in/ance1 z a silv]$ ball us$ to  
ornam5t a ,*ri/mas-tree or ! bulb ( a   
pipette1 :i* is :at ,i us$4 ,pass ?r\gh 
! op5 necks ( ! bulb a piece ( wire ab\t
 "o-tw5tie? ( an in* 9 diamet]1 & fix x 
p]man5tly & wat]-tight ^u ! wire by     
work+ into ! necks melt$ seal+-wax4 ,an 
in* or two above ! globe1 fa/5 a flat   
frame ( ?9 wire by sold]+1 or if ?is is 
too difficult1 by ty+ & seal+-wax4 ,a   
lump ( lead mu/ !n be fa/5$ or hung on  
to ! l[] end1 & gradually scrap$ away   
until ! wire frame w j be unable to =ce 
its way ?r\gh ! surface ( ! wat]4 ,none 
( ! dim5sions or mat]ials m5tion$ are ( 
importance4   ,p>aff9$ ,sieve4  ,obta9 a
 piece ( copp] wire gauze ) ab\t tw5ty  
wires to ! in*1 & cut out f x a r\nd    

piece ab\t eight in*es 9 diamet]4 ,lay x
 on a r\nd block1 ( su* a size t x      
projects ab\t "o in* all r\nd4 ,!n g5tly
 g r\nd & r\nd ) ! h&s press+ ! edge d[n
 & keep+ x flat above1 until ! sides are
 ev5ly turn$ d[n all r\nd4 ,?is is q    
easy1 because ! wires c all[ ( ! k9d (  
di/ortion necess>y4 ,!n w9d r\nd !      
turn$-up edge a few turns ( ?ick wire to
 make ! sides /iff4 ,?is ought to be    
sold]$ 9 position1 b probably c>eful    
wir+ w be good en\gh4  ,melt "s p>aff9  
wax or "o or two p>aff9 c&les ( ! be/   
quality 9 a clean flat di%1 n ov] !     
fire1 :i* w\ld be dang]\s1 b on a hot   
plate4 ,:5 melt$ & cle> l wat]1 dip !   
sieve 91 & :5 all is hot quickly take x 
out & knock x once or twice on ! table  
to %ake ! p>aff9 out ( ! holes4 ,leave  
upside d[n until cold1 & !n be c>eful n 
to scrat* or rub (f ! p>aff94 ,?is _h   
be/ be done 9 a place :]e a mess is ( no
 consequ5ce4  ,!re is no difficulty 9   
fill+ x or 9 sett+ x to float ^u wat]4  
,n>r[ ,tubes & ,capill>ity4  ,get "s    

quill-glass tube f a *emi/1 t is1 tube  
ab\t ! size ( a p54 ,if x is m ?an1 say1
 a foot long1 cut (f a piece by fir/    
mak+ a firm scrat* 9 "o place ) a       
?ree-corn]$ file1 :5 x w break at !     
place easily4 ,to make v n>r[ tube f    
?is1 hold x ne> ! ends 9 ! two h&s v    
lightly1 s t ! middle "p is high up 9 ! 
brighte/ "p ( an ord9>y bright & flat   
gas flame4 ,keep x turn+ until at la/ x 
becomes s s(t t x is difficult to hold x
 /raight4 ,x c !n be b5t into any %ape1 
b if x is want$ to be drawn out x mu/ be
 held /ill long] until ! black smoke ^u 
x beg9s to crack & peel up4 ,!n quickly 
take x out ( ! flame1 & pull ! two ends 
ap>t1 :5 a long n>r[ tube w be =m$      
betwe54 ,?is c be made f9] or co>s] by  
regulat+ ! heat & ! mann] 9 :i* x is    
pull$ out4 ,no directions w tell any "o 
s mu* z a v little practice4 ,= draw+   
out tubes ! flame ( a ,buns5 burn] or ( 
a bl[-pipe is m conv5i5t2 b = b5d+ tubes
 no?+ is s good z ! flat gas flame4 ,d n
 clean (f smoke till ! tubes are cold1 &

 d n hurry _! cool+ by wett+ or bl[+ ^u 
!m4 ,9 ! c\ntry :]e gas is n to be _h1 !
 flame ( a l>ge _s-lamp c be made to d1 
b x is n s good z a gas-flame4 ,! n>r[] 
^! tubes are1 ! high] w clean wat] be   
obs]v$ to rise 9 !m4 ,to col\r ! wat]1  
pa9ts f a col\r-box mu/ n be us$4 ,!y   
are n liquid1 & w clog ! v f9e tubes4   
,"s dye t w q dissolve 7z sug> does7 mu/
 be us$4 ,an anil9e dye1 call$ soluble  
blue1 does v well4 ,a little v9eg> add$ 
may make ! col\r la/ bett]4             
,capill>ity betwe5 ,plates4  ,two plates
 ( flat glass1 say ?ree to five in*es   
squ>e1 are requir$4 ,provid$ !y are q   
clean & well wett$ !re is no difficulty4
 ,a little soap & hot wat] w probably be
 suffici5t to clean !m4   ,te>s ( ,w9e4 
,^! are be/ se5 at dess]t 9 a glass ab\t
 half fill$ ) port4 ,a mixture ( f two  
to ?ree p>ts ( wat]1 & "o "p ( spirits (
 w9e conta9+ a v little rosanil9e 7a r$ 
anil9e dye71 to give x a nice col\r1 may
 be us$1 if port is n available4 ,a     
piece ( ! dye ab\t z l>ge z a mu/>d-se$ 

w be en\gh = a l>ge w9e-glass4 ,! sides 
( ! glass %\ld be wett$ ) ! w9e4        
,cat-,boxes4  ,e s*ool-boy kn[s h[ to   
make ^!4 ,!y are n ! boxes made by cutt+
 slits 9 pap]4 ,!y are simply made by   
fold+1 & are !n bl[n out l ! frog1 :i*  
is also made ( fold$ pap]4   ,liquid    
,beads4  ,in/ead ( melt+ gold1 wat]     
roll$ on to a table ?ickly du/$ )       
lycopodium1 or o!r f9e du/1 or          
quicksilv] roll$ or ?r[n ^u a smoo?     
table1 w %[ ! diff]5ce 9 ! %ape ( l>ge &
 small beads p]fectly4 ,a magnify+-glass
 w make ! diff]5ce m evid5t4 ,9 us+     
quicksilv]1 be c>eful t none ( x falls  
on gold or silv] co9s1 or jewell]y1 or  
plate1 or on ! ornam5tal gild+ on       
book-cov]s4 ,x w d s]i\s damage4        
,plateau's ,exp]im5t4  ,to p]=m ?is ) v 
great p]fection requires mu* c>e &      
tr\ble4 ,x is easy to succe$ up to a    
c]ta9 po9t4 ,p\r into a clean bottle    
ab\t a table-spoonful ( salad-oil1 & p\r
 ^u x a mixture ( n9e p>ts by volume    
spirits ( w9e 7n me?ylat$ spirits71 &   

sev5 p>ts ( wat]4 ,%ake up & leave = a  
day if necess>y1 :5 x w be f\nd t ! oil 
has settl$ toge!r by itself4 ,fill a    
tumbl] ) ! same mixture ( _s & wat]1 &  
!n ) a f9e glass pipe1 dipp+ ab\t       
half-way d[n1 sl[ly introduce a v little
 wat]4 ,?is w make ! liquid bel[ a      
little heavi]4 ,dip into ! oil a pipe & 
take out a little by clos+ ! upp] end ) 
! f+]1 & c>efully drop ?is into !       
tumbl]4 ,if x goes to ! bottom1 a little
 m wat] is requir$ 9 ! l[] half ( !     
tumbl]4 ,if by *ance x w n s9k at all1 a
 little m _s is want$ 9 ! upp] half4 ,at
 la/ ! oil w j float 9 ! middle ( !     
mixture4 ,m c !n be add$1 tak+ c>e to   
prev5t x f t\*+ ! sides4 ,if ! liquid   
bel[ is ev] s little heavi]1 & ! liquid 
above ev] s little light] ?an oil1 !    
drop ( oil p]haps z l>ge z a halfp5ny w 
be almo/ p]fectly r\nd4 ,x w n appe>    
r\nd if se5 ?r\gh ! glass1 because !    
glass magnifies x sideways1 b n up &    
d[n1 z may be se5 by hold+ a co9 9 !    
liquid j above x4 ,to see ! drop 9 its  

true %ape ! vessel mu/ ei!r be a globe1 
or "o side mu/ be made ( flat glass4    
,sp9n+ ! oil s z to ?r[ (f a r+ is n    
mat]ial1 b if ! read] c contrive to fix 
a disc ab\t ! size ( a ?reep5ny-piece ^u
 a /raight wire1 & sp9 x r\nd )\t %ak+  
x1 !n he w see ! r+ break (f1 & ei!r    
return if ! rotation is quickly /opp$1  
or else break up into ?ree or f\r p]fect
 little balls4 ,! disc %\ld be wett$ )  
oil be=e be+ dipp$ into ! mixture ( _s &
 wat]4   ,a ,good ,mixture =            
,soap-,bubbles4  ,common yell[ soap is  
f> bett] ?an mo/ ( ! fancy soaps1 :i*   
g5]ally conta9 a little soap & a lot (  
rubbi%4 ,ca/ille soap is v good1 & ?is  
may be obta9$ f any *emi/4  ,bubbles    
bl[n ) soap & wat] alone d n la/ long   
en\gh = _m ( ! exp]im5ts describ$1 ?\gh 
!y may sometimes be made to succe$4     
,plateau add$ glyc]9e1 :i* greatly      
improves ! la/+ quality4 ,! glyc]9e %\ld
 be pure2 common glyc]9e is n good1 b   
,price's answ]s p]fectly4 ,! wat] %\ld  
be pure di/ill$ wat]1 b if ?is is n     

available1 clean ra9-wat] w d4 ,d n     
*oose ! fir/ t runs f a ro( aft] a spell
 ( dry wea!r1 b wait till x has ra9$ =  
"s "t1 ! wat] t !n runs (f is v good1   
especially if ! ro( is blue slate or    
glass4 ,if fre% ra9-wat] is n to be _h1 
! s(te/ wat] %\ld be employ$ t c be     
obta9$4 ,in/ead ( ,ca/ille soap1        
,plateau f\nd t a pure soap prep>$ f    
olive-oil is /ill bett]4 ,?is is call$  
oleate ( soda4 ,x %\ld be obta9$ fre%ly 
prep>$ f a manufactur+ *emi/4 ,old1 dry 
/uff t has be5 kept a long "t is n s    
good4 ,i h always us$ a modification (  
,plateau's =mula1 :i* ,pr(essors ,re9old
 & ,ruck] f\nd to answ] s well4 ,!y us$ 
less glyc]9e ?an ,plateau4 ,x is be/    
made z foll[s4 ,fill a clean /opp]$     
bottle ?ree-qu>t]s full ( wat]4 ,add    
"o-=tie? "p ( its weight ( oleate (     
soda1 :i* w probably float on ! wat]4   
,leave x = a day1 :5 ! oleate ( soda w  
be dissolv$4 ,ne>ly fill up ! bottle )  
,price's glyc]9e & %ake well1 or p\r x  
into ano!r clean bottle & back aga9     

sev]al times4 ,leave ! bottle1 /opp]$ ( 
c\rse1 = ab\t a week 9 a d>k place4 ,!n 
) a syphon1 t is1 a b5t glass tube :i* w
 rea* to ! bottom inside & /ill fur!r   
outside1 draw (f ! cle> liquid f ! scum 
:i* w h collect$ at ! top4 ,add "o or   
two drops ( /rong liquid ammonia to e   
p9t ( ! liquid4 ,!n c>efully keep x 9 a 
/opp]$ bottle 9 a d>k place4 ,d n get   
out ?is /ock bottle e "t a bubble is to 
be bl[n1 b h a small work+ bottle4 ,nev]
 put any back into ! /ock4 ,9 mak+ !    
liquid d n w>m or filt] x4 ,ei!r w spoil
 x4 ,nev] leave ! /opp]s out ( ! bottles
 or all[ ! liquid to be expos$ to ! air 
m ?an is necess>y4 ,?is liquid is /ill  
p]fectly good aft] two ye>s' keep+4 ,i h
 giv5 ^! directions v fully1 n because  
,i feel sure t all ! details are        
ess5tial1 b because x exactly describes 
! way ,i happ5 to make x1 & because ,i h
 nev] f\nd any o!r solution s good4     
,ca/ille soap1 ,price's glyc]9e1 &      
ra9-wat] w almo/ c]ta9ly answ] e        
purpose1 & ! same proportions w probably

 be f\nd to "w well4   ,r+s = ,bubbles4 
,^! may be made ( any k9d ( wire4 ,i h  
us$ t9n$ iron ab\t "o-tw5tie? ( an in* 9
 diamet]4 ,! jo9t %\ld be smoo?ly sold]$
 )\t lumps4 ,if sold]+ is a difficulty1 
!n use ! ?9ne/ wire t is /iff en\gh to  
support ! bubbles /eadily1 & make ! jo9t
 by twi/+ ! end ( ! wire r\nd two or    
?ree times4 ,r+s two in*es 9 diamet] are
 conv5i5t4 ,i h se5 t dipp+ ! r+s 9     
melt$ p>aff9 is recomm5d$1 b ,i h n f\nd
 any advantage f ?is4 ,! nice/ mat]ial =
 ! light r+s is ?9 alum9ium wire1 ab\t z
 ?ick z a f9e p9 7,no4 #bf to #cj1 ,b4  
,w4 ,g471 & z ?is _c be sold]$1 ! ends  
mu/ be twi/$4 ,if ?is is n to be _h1 v  
f9e wire1 ne>ly z f9e z a hair 7,no4    
#cf1 ,b4 ,w4 ,g471 ( copp] or ( any o!r 
metal1 w answ]4 ,! r+s %\ld be wett$ ) !
 soap mixture be=e a bubble is plac$ ^u 
!m1 & mu/ always be well wa%$ & dri$ :5 
done )4   ,?reads 9 ,r+4  ,!re is no    
difficulty 9 %[+ ^! exp]im5ts4 ,! r+ ) !
 ?read may be dipp$ 9 ! soap solution1  
or /rok$ across ) ! edge ( a piece (    

pap] or india-rubb] %eet t has be5 dipp$
 9 ! liquid1 s z to =m a film on bo?    
sides ( ! ?read4 ,a ne$le t has also be5
 wett$ ) ! soap may be us$ to %[ t !    
?reads are loose4 ,! same ne$le held = a
 mom5t 9 a c&le-flame supplies a        
conv5i5t means ( break+ ! film4   ,bl[  
out ,c&le ) ,soap-,bubble4  ,= ?is1 !   
bubble %\ld be bl[n on ! end ( a %ort   
wide pipe1 spread out at "o end to give 
a bett] hold = ! bubble4 ,! t9 funnel   
suppli$ ) an ord9>y gazog5e answ]s      
p]fectly4 ,?is %\ld be wa%$ be=e x is   
us$ aga9 = fill+ ! gazog5e4   ,bubbles  
balanc$ aga9/ "o ano!r4  ,^! exp]im5ts  
are mo/ conv5i5tly made on a small      
scale4 ,pieces ( ?9 brass tube1         
?ree-eigh?s or half an in* 9 diamet]1   
are suitable4 ,x is be/ to h pieces (   
app>atus1 specially prep>$ ) taps1 =    
easily & quickly /opp+ ! air f leav+    
ei!r bubble1 & = putt+ ! two bubbles    
into communication :5 requir$4 ,x %\ld n
 be difficult to contrive to p]=m !     
exp]im5ts1 us+ india-rubb] connect+     

tubes1 p9*$ ) spr+ clips to take ! place
 ( taps4 ,!re is "o little detail :i* j 
makes ! diff]5ce betwe5 success &       
failure4 ,?is is to supply a m\?-piece =
 bl[+ ! bubble1 made ( glass tube1 :i*  
has be5 drawn out s f9e t ^! little     
bubbles _c be bl[n out sudd5ly by       
accid5t4 ,x is v difficult1 o!rwise1 to 
adju/ ! quantity ( air 9 su* small      
bubbles ) any accuracy4 ,9 balanc+ a    
sph]ical aga9/ a cyl9drical bubble1 !   
%ort piece ( tube1 into :i* ! air is    
suppli$1 mu/ be made s t x c be easily  
mov$ to or f a fix$ piece ( ! same size 
clos$ at ! o!r end4 ,!n ! two ends ( !  
%ort tube mu/ h a film spread ov] !m ) a
 piece ( pap]1 or india-rubb]1 b !re mu/
 be no film /ret*$ across ! end ( ! fix$
 tube4 ,! two tubes mu/ at fir/ be ne>  
toge!r1 until ! sph]ical bubble has be5 
=m$4 ,!y may !n be sep>at$ gradually m &
 m1 & air bl[n 9 s z to keep ! sides ( !
 cyl9d] /raight1 until ! cyl9d] is      
suffici5tly long to be ne>ly un/able4 ,x
 w !n f> m evid5tly %[1 by its *ange (  

=m1 ?an x w\ld if x 7 %ort1 :5 !        
pressure due to ! sph]ical bubble       
exactly balances t due to a cyl9drical  
"o4 ,if ! %ad[ ( ! bubbles1 or an image 
=m$ by a l5s on a scre51 is !n measur$1 
x w be f\nd t ! sph]e has a diamet] :i* 
is v accurately d\ble t ( ! cyl9d]4     
,?aumatrope = %[+ ! ,=mation &          
,oscillations ( ,drops4  ,! exp]im5t %[+
 ! =mation ( wat]-drops c be v p]fectly 
imitat$1 & ! movem5ts actually made     
visible1 )\t any necessity = us+ liquids
 at all1 by simply conv]t+ ,fig4 #ce 7at
 end ( book7 into ! old-fa%ion$ in/rum5t
 call$ a ?aumatrope4 ,:at w !n be se5 is
 a true repres5tation1 because ! =ms 9 !
 figure are copies ( a s]ies (          
photographs tak5 f ! mov+ drops at !    
rate ( =ty-?ree photographs 9 two       
seconds4#b  ,footnote #b3 ,= p>ticul>s  
see ,philosophical ,magaz9e1 ,septemb]  
#ahij4  ,obta9 a piece ( good c>d-bo>d z
 l>ge z ! figure1 & hav+ bru%$ x all ov]
 on "o side ) ?9 pa/e1 lay ! figure ^u  
x1 & press x d[n ev5ly4 ,place x ^u a   

table1 & cov] x ) a few ?icknesses (    
blott+-pap]1 & lay ov] all a flat piece 
( bo>d l>ge en\gh to cov] x4 ,weights   
suffici5t to keep x all flat may be     
add$4 ,?is mu/ be left all night at     
lea/1 until ! c>d is q dry1 or else x w 
curl up & be useless4 ,n[ ) a %>p *isel 
or knife1 b a *isel if possible1 cut out
 ! =ty-?ree slits ne> ! edge1 accurately
 foll[+ ! outl9e indicat$ 9 black &     
:ite1 & keep+ ! slits z n>r[ z possible4
 ,!n cut a hole 9 ! middle1 s z to fit !
 project+ "p ( a sew+-ma*9e cotton-reel1
 & fa/5 ! cotton-reel on ! side away f !
 figure ) glue or small nails4 ,x mu/ be
 fix$ exactly 9 ! middle4 ,! edge %\ld (
 c\rse be cut d[n to ! outside ( ! black
 rim4  ,n[ hav+ f\nd a p5cil or o!r rod 
on :i* ! cotton-reel w freely turn1 use 
?is z an axle1 & hold+ ! disc up 9 front
 ( a look+-glass1 & 9 a good light1     
sl[ly & /eadily make x turn r\nd4 ,!    
image ( ! disc se5 ?r\gh ! slit 9 !     
look+-glass w !n p]fectly repres5t e    
feature ( ! gr[+ & fall+ drop4 ,z ! drop

 gr[s x w gradually become too heavy to 
be support$1 a wai/ w !n beg9 to =m :i* 
w rapidly get n>r[]1 until ! drop at la/
 breaks away4 ,x w be se5 to cont9ue its
 fall until x has disappe>$ 9 ! liquid  
bel[1 b x has n mix$ ) ?is1 & s x w     
pres5tly appe> aga91 hav+ b\nc$ out ( ! 
liquid4 ,z x falls x w be se5 to vibrate
 z ! result ( ! sudd5 release f !       
"o-sid$ pull4 ,! neck :i* 0 drawn out w 
mean:ile h ga!r$ itself 9 ! =m ( a      
little drop1 :i* w !n be viol5tly hit by
 ! oscillations ( ! rema9+ p5dant drop  
above1 & driv5 d[n4 ,! p5dant drop w be 
se5 to vibrate & gr[ at ! same "t1 until
 x aga9 breaks away z be=e1 & s !       
ph5om5a are repeat$4  ,9 ord] to        
p]fectly reproduce ! exp]im5t1 ! axle   
%\ld be firmly held ^u a /&1 & ! spe$   
%\ld n exce$ "o turn 9 two seconds4  ,! 
effect is /ill m real if a scre5 is     
plac$ betwe5 ! disc & ! mirror1 :i* w   
only all[ "o ( ! drops to be se54       
,wat]-drops 9 ,p>aff9 & ,bisulphide (   
,c>bon4  ,all t 0 said 9 describ+ !     

,plateau exp]im5t applies "h4 ,p]fectly 
sph]ical & l>ge drops ( wat] c be =m$ 9 
a mixture s made t ! l[] p>ts are v     
little heavi]1 & ! upp] p>ts v little   
light]1 ?an wat]4 ,! addition (         
bisulphide ( c>bon makes ! mixture      
heavi]4 ,?is liquid--bisulphide (       
c>bon--is v dang]\s1 & has a mo/        
dreadful smell1 s t x _h bett] n be     
br\ght into ! h\se4 ,! =m ( a hang+     
drop1 & ! way 9 :i* x breaks (f1 c be   
se5 if wat] is us$ 9 p>aff9 alone1 b x  
is mu* m evid5t if a little bisulphide (
 c>bon is mix$ ) ! p>aff91 s t wat] w   
s9k sl[ly 9 ! mixture4 ,pieces ( glass  
tube1 op5 at bo? ends f half an in* to  
"o in* 9 diamet]1 %[ ! action be/4 ,hav+
 p\r$ "s wat] col\r$ blue into a glass  
vessel1 & cov]$ x to a dep? ( sev]al    
in*es ) p>aff91 or ! p>aff9 mixture1 dip
 ! pipe d[n into ! wat]1 hav+ fir/ clos$
 ! upp] end ) ! ?umb or ! palm ( ! h&4  
,on !n remov+ ! h&1 ! wat] w ru% up     
inside ! tube4 ,aga9 close ! upp] end z 
be=e1 & raise ! tube until ! l[] end is 

well above ! wat]1 ?\gh /ill imm]s$ 9 ! 
p>aff94 ,!n all[ air to ent] ! pipe v   
sl[ly by j roll+ ! ?umb ! lea/ bit to "o
 side4 ,! wat] w escape sl[ly & =m a    
l>ge gr[+ drop1 ! size ( :i*1 be=e x    
breaks away1 w dep5d on ! d5sity ( !    
mixture & ! size ( ! tube4  ,to =m a    
wat] cyl9d] 9 ! p>aff9 ! tube mu/ be    
fill$ ) wat] z be=e1 b ! upp] end mu/ n[
 be left op54 ,!n :5 all is quiet ! tube
 is to be r rapidly )drawn 9 ! direction
 ( its own l5g?1 :5 ! wat] :i* 0 )9 x w 
be left beh9d 9 =m ( a cyl9d]1 surr\nd$ 
by ! p>aff94 ,x w !n break up into      
sph]es s sl[ly1 9 ! case ( a l>ge tube1 
t ! op]ation c be wat*$4 ,! dep? (      
p>aff9 %\ld be q t5 times ! diamet] ( ! 
tube4  ,to make bubbles ( wat] 9 !      
p>aff91 ! tube mu/ be dipp$ d[n into !  
wat] ) ! upp] end op5 all ! "t1 s t !   
tube is mo/ly fill$ ) p>aff94 ,x mu/ !n 
be clos$ = a mom5t above & rais$ till ! 
end is completely out ( ! wat]4 ,!n if  
air is all[$ to ent] sl[ly1 & ! tube is 
g5tly rais$1 bubbles ( wat] fill$ )     

p>aff9 w be =m$ :i* c be made to sep>ate
 f ! pipe1 l soap-bubbles f a *ur*w>d51 
by a suitable sudd5 movem5t4 ,if a numb]
 ( wat]-drops are float+ 9 ! p>aff9 9 ! 
pipe1 & ?is c be easily arrang$1 !n !   
bubbles made w conta9 possibly a numb] (
 o!r drops1 or ev5 o!r bubbles4 ,a v    
little bisulphide ( c>bon p\r$ c>efully 
d[n a pipe w =m a heavy lay] above !    
wat]1 on :i* ^! comp\nd bubbles w rema9 
float+4  ,cyl9drical bubbles ( wat] 9   
p>aff9 may be made by dipp+ ! pipe d[n  
into ! wat] & )draw+ x quickly )\t ev]  
clos+ ! top at all4 ,^! break up into   
sph]ical bubbles 9 ! same way t ! cyl9d]
 ( liquid broke up into sph]es ( liquid4
   ,bead$ ,spid]-webs4  ,^! are f\nd 9 !
 spiral "p ( ! webs ( all ! geometrical 
spid]s4 ,! beautiful geometrical webs   
may be f\nd out ( doors 9 abundance 9 ! 
autumn1 or 9 gre5-h\ses at almo/ any "t 
( ! ye>4 ,to m\nt ^! webs s t ! beads   
may be se51 take a small flat r+ ( any  
mat]ial1 or a piece ( c>d-bo>d ) a hole 
cut out ) a gun-wad cutt]1 or o!rwise4  

,sme> ! face ( ! r+1 or ! c>d1 ) a v    
little /rong gum4 ,*oose a fre%ly-made  
web1 & !n pass ! r+1 or ! c>d1 across ! 
web s t "s ( ! spiral web 7n ! c5tral "p
 ( ! web7 rema9s /ret*$ across ! hole4  
,?is mu/ be done )\t t\*+ or damag+ !   
pieces t are /ret*$ across1 except at _!
 ends4 ,! beads are too small to be se5 
) ! nak$ eye4 ,a /rong magnify+-glass1  
or a l[ p[] microscope1 w %[ ! beads &  
_! m>vell\s regul>ity4 ,! beads on !    
webs ( v "y spid]s are n s regul> z ^?  
on spid]s t are fully gr[n4 ,^?         
beautiful beads1 easily visible to !    
nak$ eye1 on spid] l9es 9 ! e>ly morn+ (
 an autumn day1 are n made by ! spid]1 b
 are simply dew4 ,!y v p]fectly %[ !    
sph]ical =m ( small wat]-drops4         
,photographs ( ,wat]-jets4  ,^! are     
easily tak5 by ! me?od describ$ by ,mr4 
,*i*e/] ,bell4 ,! fla% ( light is       
produc$ by a %ort sp>k f a few          
,leyd5-j>s4 ,! f\nta91 or jet1 %\ld be  
five or six feet away f ! sp>k1 & !     
photographic plate %\ld be held z close 

to ! /ream ( wat] z is possible )\t     
t\*+4 ,! %ad[ is !n s def9ite t !       
photograph1 :5 tak51 may be exam9$ ) a  
p[]ful l5s1 & w /ill appe> %>p4 ,any    
rapid dry plate w d4 ,! room1 ( c\rse1  
mu/ be q d>k :5 ! plate is plac$ 9      
position1 & ! sp>k !n made4 ,! regul>   
break+ up ( ! jet may be effect$ by s\nd
 produc$ 9 almo/ any way4 ,! /raight    
jet1 ( :i* ,fig4 #da is a repres5tation1
 magnifi$ ab\t ?ree & a qu>t] times1 0  
regul>ly brok5 up by simply :i/l+ to x )
 a key4 ,! f\nta9s 7 brok5 up regul>ly  
by fa/5+ ! nozzle to "o end ( a long    
piece ( wood clamp$ at ! end to ! /& ( a
 tun+-=k1 :i* 0 kept s\nd+ by electrical
 means4 ,an ord9>y tun+-=k1 made to re/ 
:5 s\nd+ aga9/ ! wood5 support ( !      
nozzle1 w answ] q z well1 b is n q s    
conv5i5t4 ,! jet w break up be/ to c]ta9
 notes1 b x may be tun$ to a great ext5t
 by alt]+ ! size ( ! orifice or !       
pressure ( ! wat]1 or bo?4   ,f\nta9 &  
,seal+-wax4  ,x is almo/ impossible to  
fail ov] ?is v /rik+ yet simple         

exp]im5t4 ,a f\nta9 ( almo/ any size1 at
 any rate betwe5 "o-fiftie? & a qu>t] ( 
an in* 9 ! smoo? "p1 & up to eight feet 
high1 w cease to scatt] :5 ! seal+-wax  
is rubb$ ) flannel & held a few feet    
away4 ,a suitable size ( f\nta9 is "o   
ab\t f\r feet high1 com+ f an orifice   
any:]e ne> "o-sixte5? ( an in* 9        
diamet]4 ,! nozzle %\ld be incl9$ s t ! 
wat] falls slightly on "o side4 ,!      
seal+-wax may be electrifi$ by be+ rubb$
 on ! coat-sleeve1 or on a piece ( fur  
or flannel :i* is dry4 ,x w !n make     
little pieces ( pap] or cork dance1 b x 
w /ill act on ! f\nta9 :5 x has ceas$ to
 produce any visible effect on pieces ( 
pap]1 or ev5 on a delicate gold-leaf    
electroscope4   ,b\nc+ ,wat]-jets4  ,?is
 beautiful exp]im5t ( ,"l ,rayleigh's   
requires a little managem5t to make x "w
 9 a satisfactory mann]4 ,take a piece (
 quill-glass tube & draw x out to a v   
slight ext5t 7see a =m] note71 s z to   
make a neck ab\t "o-eigh? ( an in* 9    
diamet] at ! n>r[e/ "p4 ,break ! tube j 

at ?is place1 aft] fir/ nick+ x !re ) a 
file4 ,connect ea* ( ^! tubes by means (
 an india-rubb] pipe1 or o!rwise1 ) a   
supply ( wat] 9 a bottle1 & p9* ! tubes 
) a screw-clip until two equal jets (   
wat] are =m$4 ,s hold ! nozzles t ^!    
meet 9 _! smoo? portions at e small     
angle4 ,!y w !n = a %ort "t b\nce away f
 "o ano!r )\t mix+4 ,if ! air is v du/y1
 if ! wat] is n clean1 or if air-bubbles
 are c>ri$ along 9 ! pipes1 ! two jets w
 at once jo9 toge!r4 ,9 ! arrangem5t t  
,i us$ 9 ! lant]n1 ! two nozzles 7 ne>ly
 horizontal1 "o 0 ab\t half an in* above
 ! o!r1 & !y 7 v slightly conv]g+4 ,!y 7
 fa/5$ 9 _! position by melt+ ^u !m a   
little seal+-wax4 ,india-rubb] pipes    
connect$ !m ) two bottles ab\t six in*es
 above !m1 & screw-clips 7 us$ to       
regulate ! supply4 ,"o ( ! bottles 0    
made to /& on ?ree pieces ( seal+-wax to
 electrically insulate x1 & !           
correspond+ nozzle 0 only held by its   
seal+-wax fa/5+4 ,! wat] 9 ! bottles _h 
be5 filt]$1 & "o 0 col\r$ blue4 ,if ^!  

precautions are tak51 ! jets w rema9    
di/9ct q long en\gh1 b are in/antly     
caus$ to recomb9e by a piece (          
electrifi$ seal+-wax six or eight feet  
away4 ,!y may be sep>at$ aga9 by t\*+ ! 
wat] issu+ ne> "o nozzle ) ! f+]1 :i*   
deflects x2 on quietly remov+ ! f+] !   
jet takes up its old position & b\nces  
(f ! o!r z be=e4 ,!y c ?us be sep>at$ & 
made to comb9e t5 or a doz5 times 9 a   
m9ute4   ,f\nta9 & ,int]mitt5t ,light4  
,?is c be successfully %[n to a l>ge    
numb] ( p at once only by us+ an        
electric arc1 b !re is no occasion to   
produce ?is light if n m ?an "o p]son at
 a "t wi%es to see ! evolution ( !      
drops4 ,x is !n m]ely necess>y to make !
 f\nta9 play 9 front ( a bright         
backgr\nd su* z ! sky1 to break x up ) a
 tun+-=k or o!r musical s\nd z describ$1
 & !n to look at x ?r\gh a c>d disc     
equally divid$ ne> ! edge into spaces   
ab\t two or ?ree in*es wide1 ) a hole   
ab\t "o-eigh? ( an in* 9 diamet] betwe5 
ea* pair ( spaces4 ,a disc ( c>d five   

in*es 9 diamet]1 ) six equidi/ant holes 
half an in* f ! edge1 answ]s well4 ,!   
disc mu/ be made to sp9 by any means v  
regul>ly at su* a spe$ t ! tun+-=k1 or  
/ret*$ /r+ if ?is be us$1 :5 look$ at   
?r\gh ! holes1 appe>s quiet1 or ne>ly   
quiet1 :5 made to vibrate4 ,! sep>ate   
drops w !n be se51 & ev]y?+ describ$ 9 !
 prec$+ pages1 & a great deal m1 w be   
evid5t4 ,?is is "o ( ! mo/ fasc9at+     
exp]im5ts1 & x is well wor? :ile to make
 an ef=t to succe$4 ,! little motor t ,i
 us$ is "o ( ,cuttriss & ,co4's ,p4 #a4 
motors1 :i* are v conv5i5t = exp]im5ts (
 ?is k9d4 ,x 0 driv5 by f\r ,grove's    
cells4 ,^! make x rotate too fa/1 b !   
spe$ c be r$uc$ by mov+ ! bru%es        
slightly t[>ds ! position us$ = rev]s+ !
 motor1 until ! spe$ is almo/ exactly   
"r4 ,x is be/ to arrange t x goes only j
 too fa/1 !n ! spe$ c be p]fectly       
regulat$ by a v light pressure ( ! f+]  
on ! end ( ! axle4   ,mr4 ,*i*e/]       
,bell's ,s++ ,wat]-jet4  ,= ^! exp]im5ts
 a v f9e hole ab\t "o sev5ty-fif? ( an  

in* 9 diamet] is mo/ suitable4 ,to obta9
 ?is1 ,mr4 ,bell holds ! end ( a        
quill-glass tube 9 a bl[-pipe flame1 &  
con/antly turns x r\nd & r\nd until !   
end is almo/ entirely clos$ up4 ,he !n  
sudd5ly & =cibly bl[s into ! pipe4 ,out 
( sev]al nozzles made 9 ?is way1 "s are 
sure to d well4 ,"l ,rayleigh makes     
nozzles g5]ally by cem5t+ to ! end ( a  
glass 7or metal7 pipe a piece ( ?9 %eet 
metal 9 :i* a hole ( ! requir$ size has 
be5 made4 ,! wat] pressure %\ld be      
produc$ by a head ( ab\t fifte5 feet4 ,!
 wat] mu/ be q free f du/ & f           
air-bubbles4 ,?is may be effect$ by mak+
 x pass ?r\gh a piece ( tube /uff$ full 
( flannel1 or cotton-wool1 or some?+ ( !
 k9d to act z a filt]4 ,!re %\ld be a   
y>d or s ( good black india-rubb] tube1 
ab\t "o-eigh? ( an in* 9 diamet] inside1
 betwe5 ! filt] & ! nozzle4 ,x is be/ n 
to take ! wat] direct f ! wat]-ma91 b f 
a ci/]n ab\t fifte5 feet above ! nozzle4
 ,if no ci/]n is available1 a pail (    
wat] tak5 up-/airs1 ) a pipe com+ d[n1  

is an excell5t sub/itute1 & ?is has !   
fur!r advantage t ! head ( wat] c be    
easily *ang$ s z to arrive at ! be/     
result4  ,! re/ ( ! app>atus is v       
simple4 ,x is m]ely necess>y to /ret* & 
tie ov] ! end ( a tube ab\t half an in* 
9 diamet] a piece ( ?9 india-rubb] %eet1
 cut f an air-ball t has n be5 bl[n out4
 ,! tube1 :i* may be ( metal or ( glass1
 may ei!r be fa/5$ to a heavy foot1 9   
:i* case a side tube mu/ be jo9$ to x1 z
 9 ,fig4 #dg1 or x may be op5 at bo?    
ends & be held 9 a clamp4 ,x is well to 
put a cone ( c>d-bo>d on ! op5 end      
7,fig4 #dh71 if ! s\nd is to be he>d by 
_m at a "t4 ,if ! exp]im5t] alone wi%es 
to he> z well z possible :5 fa9t s\nds  
are produc$1 he %\ld c>ry a piece (     
smoo? india-rubb] tube ab\t half an in* 
9 diamet] f ! op5 end to 8 e>4 ,?is1    
h[ev]1 w\ld ne>ly deaf5 him ) su* l\d   
noises z ! tick ( a wat*4   ,bubbles &  
,e!r4  ,exp]im5ts ) e!r mu/ be p]=m$ )  
great c>e1 because1 l ! bisulphide (    
c>bon1 x is dang]\sly inflammable4 ,!   

bottle ( e!r mu/ nev] be br\ght ne> a   
light4 ,if a l>ge quantity is spill$1 ! 
heavy vap\r is apt to run along ! floor 
& ignite at a fire1 ev5 on ! o!r side ( 
a room4 ,any vessel may be fill$ ) !    
vap\r ( e!r by m]ely p\r+ ! liquid ^u a 
piece ( blott+-pap] rea*+ up to ! level 
( ! edge4 ,v little is requir$1 say half
 a w9e-glassful1 = a bas9 t w\ld hold a 
gallon or m4 ,9 a draughty place ! vap\r
 w be lo/ 9 a %ort "t4 ,bubbles c be set
 to float ^u ! vap\r )\t any difficulty4
 ,!y may be remov$ 9 five or t5 seconds 
by means ( "o ( ! small light r+s ) a   
h&le1 provid$ t ! r+ is wett$ ) ! soap  
solution & has no film /ret*$ across x4 
,if tak5 to a light at a safe di/ance ! 
bubble w imm$iately bur/ into a blaze4  
,if a neighb\r+ light is n close d[n to 
! table1 b well up above ! j> on a /&1 x
 may be ne> ) b little risk4 ,to %[ !   
burn+ vap\r1 ! same wide tube t 0 us$ to
 bl[ out ! c&le w answ] well4 ,! pe>    
%ape ( ! bubble1 ow+ to its increas$    
weight aft] be+ held 9 ! vap\r = t5 or  

fifte5 seconds1 is evid5t en\gh on its  
removal1 b ! fall+ /ream ( heavy vap\r1 
:i* comes out aga9 aft]w>ds1 c only be  
%[n if its %ad[ is ca/ ^u a scre5 by    
means ( a bright light4   ,exp]im5t )   
,int]nal ,bubbles4  ,= ^! exp]im5ts1    
next to a good solution1 ! pipe is ( !  
greate/ importance4 ,a *ur*w>d5 is no   
use4 ,a glass pipe #e_/af in* 9 diamet] 
at ! m\? is be/4 ,if ?is is m]ely a tube
 b5t ne> ! end ?r\gh a "r angle1 moi/ure
 cond5s$ 9 ! tube w 9 "t run d[n &      
de/roy ! bubble occasionally1 :i* is v  
annoy+ 9 a difficult exp]im5t4 ,i h made
 = myself ! pipe ( :i* ,fig4 #fg is a   
full size repres5tation1 & ,i d n ?9k t 
x is possible to improve ^u ?is4 ,^? :o 
are n glass-bl[]s w be able1 ) ! help ( 
cork1 to make a pipe ) a trap z %[n 9   
,fig4 #fh1 :i* is z good1 except 9      
appe>ance & h&9ess4  ,9 knock+ bubbles  
toge!r to %[ t !y d n t\*1 c>e mu/ be   
tak5 to avoid lett+ ei!r bubble meet any
 projection 9 ! o!r1 su* z ! wire r+1 or
 a heavy drop ( liquid4 ,ei!r w in/antly

 de/roy ! two bubbles4 ,!re is also a   
limit to ! viol5ce :i* may be us$1 :i*  
exp]i5ce w soon indicate4  ,9 pu%+ a    
bubble ?r\gh a r+ small] ?an itself1 by 
means ( a flat film on ano!r r+1 x is   
important t ! bubble %\ld n be too l>ge2
 b a l>g] bubble c be pu%$ ?r\gh ?an    
w\ld be expect$4 ,x is n s easy to pu% x
 up z d[n because ( ! heavy drop (      
liquid1 :i* x is difficult to completely
 dra9 away4  ,illu/ration3 ,fig4 #fg4   
,l5g? ( ,/em #i ,in*es  ,illu/ration3   
,fig4 #fh4 ,l5g? ( ,/em #i ,in*es  ,to  
bl[ "o bubble inside ano!r1 ! fir/1 z   
l>ge z an av]age orange1 %\ld be bl[n on
 ! l[] side ( a horizontal r+4 ,a light 
wire r+ %\ld !n be hung on to ?is bubble
 to slightly pull x out ( %ape4 ,= ?is  
purpose ?9 alum9ium r+s are h>dly heavy 
en\gh1 & s ei!r a heavi] metal %\ld be  
us$1 or a small weight %\ld be fa/5$ to 
! h&le ( ! r+4 ,! r+ %\ld be s heavy t !
 sides ( ! bubble make an angle ( ?irty 
or =ty degrees ) ! v]tical1 :]e !y meet 
! r+ z indicat$ 9 ,fig4 #ef4 ,! wett$   

end ( ! pipe is n[ to be ins]t$ ?r\gh ! 
top ( ! bubble1 until x has p5etrat$ a  
cle> half in* or s4 ,a new bubble c n[  
be bl[n any size almo/ t may be desir$4 
,to remove ! pipe a sl[ motion w be     
fatal1 because x w raise ! inn] bubble  
until x & ! out] "o bo? meet ! pipe at !
 same place4 ,?is w br+ !m into true    
contact4 ,on ! o!r h&1 a viol5t j]k w   
almo/ c]ta9ly produce too great a       
di/urbance4 ,a r rapid motion1 or a     
slight j]k1 is all t is requir$4 ,x is  
advisable be=e pass+ ! pipe up ?r\gh !  
l[] r+1 s z to t\* ! inn] bubble1 & s   
dra9 away ! heavy drop1 to /eady ?is ) !
 o!r h&4 ,! sup]flu\s liquid c !n be    
dra9$ f bo? bubbles simultane\sly4 ,c>e 
mu/ be tak5 aft] ?is t ! inn] bubble is 
n all[$ to come aga9/ ei!r wire r+1 nor 
mu/ ! pipe be pass$ ?r\gh ! side :]e !  
two bubbles are v close toge!r4 ,to peel
 (f ! l[] r+ x %\ld be pull$ d[n a v    
little way & !n incl9$ to "o side4 ,!   
peel+ w !n />t m readily1 b z soon z x  
has begun ! r+ %\ld be rais$ s z n to   

make ! peel+ too rapid1 o!rwise ! f9al  
j]k1 :5 x leaves ! l[] r+1 w be too mu* 
= ! bubbles to )/&4  ,bubbles col\r$ )  
fluoresc9e1 or uran9e1 d n %[ _!        
brilliant fluoresc5ce unless sunlight or
 electric light is conc5trat$ ^u !m ) a 
l5s or mirror4 ,! quantity ( dye requir$
 is s small t x may be difficult to take
 little en\gh4 ,z mu* z c be pick$ up on
 ! la/ eigh? ( an in* ( a po9t$ p5-knife
 w be1 r\ghly speak+1 en\gh = a         
w9e-glassful ( ! soap solution4 ,if !   
quantity is increas$ beyond some?+ l !  
proportion /at$1 ! fluoresc5ce becomes  
less & v soon disappe>s4 ,! be/ quantity
 c be f\nd 9 a few m9utes by trial4  ,to
 bl[ bubbles conta9+ ei!r coal-gas or   
air1 or a mixture ( ! two1 ! mo/        
conv5i5t plan is to h a small ,t-%ap$   
glass tube :i* c be jo9$ by "o arm ( !  
,t to ! bl[-pipe by means ( a %ort piece
 ( india-rubb] tube1 & be connect$ by   
its v]tical limb ) a suffici5t l5g? (   
india-rubb] pipe1 "o-eigh? ( an in* 9   
diamet] inside1 to rea* to ! floor1 aft]

 :i* x may be connect$ by any k9d ( pipe
 ) ! gas supply4 ,! gas c be /opp$ ei!r 
by p9*+ ! india-rubb] tube ) ! left h&1 
if t is at lib]ty1 or by tread+ on x if 
bo? h&s are occupi$4 ,mean:ile air c be 
bl[n 9 by ! o!r arm ( ! ,t1 & ! end     
clos$ by ! tongue :5 gas alone is       
requir$4 ,?is end ( ! tube %\ld be      
slightly spread out :5 hot by rapidly   
pu%+ into x ! cold tang ( a file1 &     
twi/+ x at ! same "t1 s t x may be      
lightly held by ! tee? )\t fe> ( slipp+4
  ,if a light ,t-piece or s great a l5g?
 ( small india-rubb] tube _c be obta9$1 
!n ! m\? mu/ be remov$ f ! pipe & !     
india-rubb] tube slipp$ 9 :5 air is to  
be *ang$ = gas4 ,?is makes !            
manipulation m difficult1 b all !       
exp]im5ts1 except ! "o ) ?ree bubbles1 c
 be s c>ri$ out4  ,! pipe mu/ 9 e case  
be made to ent] ! highe/ po9t ( a bubble
 9 ord] to />t an int]nal "o4 ,if x is  
pu%$ horizontally ?r\gh ! side1 ! inn]  
bubble is sure to break4 ,if ! inn]     
bubble is be+ bl[n ) gas1 x w soon t5d  

to rise4 ,! pipe mu/ !n be turn$ ov] 9  
su* a mann] t ! inn] bubble does n creep
 along x1 & s meet ! out] "o :]e        
p5etrat$ by ! pipe4 ,a few trials w %[  
:at is meant4 ,! inn] bubble may !n be  
all[$ to re/ aga9/ ! top ( ! out] "o    
:ile be+ enl>g$4 ,:5 x is desir$ aft]   
)draw+ ! pipe to bl[ m air or gas into  
ei!r ! inn] or ! out] bubble1 x is n    
safe aft] ins]t+ ! pipe aga9 to beg9 to 
bl[ at once2 ! film :i* is n[ /ret*$    
across ! m\? ( ! pipe w probably become 
a ?ird bubble1 & ?is1 "u ! circum/ances1
 is almo/ c]ta9 to cause a failure4 ,an 
in/antane\s )drawal ( ! air de/roys ?is 
film by draw+ x into ! pipe4 ,air or gas
 may !n be bl[n )\t dang]4  ,if ! same  
exp]im5t is p]=m$ ^u a light r+ ) cotton
 & pap] atta*$1 ! left h& w be occupi$ 9
 hold+ ?is r+1 & !n ! gas mu/ be        
controll$ by ! foot1 or by a fri5d4 ,!  
light r+ %\ld be q two in*es 9 diamet]4 
,if1 :5 ! inn] bubble has begun to c>ry 
away ! r+1 c41 ! pap] is caught hold (1 
x is possible1 by a judici\s pull1 to   

cause ! two bubbles to leave ! r+ & s   
escape into ! air "o inside ! o!r4 ,=   
?is purpose ! smalle/ r+ t w c>ry ! pap]
 %\ld be us$4 ,) l>g] r+s ! same effect 
may be produc$ by incl9+ ! r+1 & s all[+
 ! out] bubble to peel (f1 or by plac+ !
 m\? ( ! pipe aga9/ ! r+ & bl[+ a ?ird  
bubble 9 real contact ) ! r+ & ! out]   
bubble4 ,?is w assi/ ! peel+ process4   
,to bl[ ?ree bubbles1 "o inside ! o!r   
two1 is m difficult4 ,! foll[+ plan ,i h
 f\nd to be fairly c]ta94 ,fir/ bl[     
above ! r+ a bubble ! size ( a l>ge     
orange4 ,!n take a small r+ ab\t an in* 
9 diamet]1 ) a /raight wire com+ d[n f  
"o side to act z a h&le1 & aft] wett+ x 
) ! solution1 pass x c>efully up ?r\gh !
 fix$ r+ s t ! small r+ is held well    
inside ! bubble4 ,n[ pass ! pipe1 fre%ly
 dipp$ 9 ! solution1 into ! out] or ,no4
 #a bubble until x is q close to ! small
 r+1 & beg9 to bl[ ! ,no4 #b bubble4    
,?is mu/ be />t$ ) ! pipe almo/ 9       
contact ) ! inn] r+1 z ! film on ?is r+ 
w\ld de/roy a bubble t _h atta9$ any    

size4 ,)draw ! pipe1 dip x into !       
liquid1 & ins]t x into ! inn] bubble1   
tak+ c>e to keep ^! two bubbles f meet+ 
any:]e4 ,n[ bl[ a l>ge gas-bubble1 :i*  
may re/ aga9/ ! top ( ,no4 #b :ile x is 
gr[+4 ,no4 #b may n[ re/ aga9/ ! top (  
,no4 #a )\t dang]4 ,remove pipe f ,no4  
#c by g5tly l[]+ x1 & let "s gas into   
,no4 #b to make x light]1 & at ! same "t
 dim9i% ! pressure betwe5 ,nos4 #b & #c4
 ,pres5tly ! small r+ c be peel$ (f ,no4
 #b & remov$ altoge!r4 ,b if !re is a   
difficulty 9 accompli%+ ?is1 )draw !    
pipe f ,no4 #b & bl[ air into ,no4 #a to
 enl>ge x1 :i* w make ! process easi]4  
,!n remove ! pipe f ,no4 #a4 ,! ?ree    
bubbles are n[ re/+ "o inside ! o!r4 ,by
 bl[+ a f\r? bubble1 z describ$ above1  
aga9/ ! fix$ r+1 ,no4 #a bubble w peel  
(f1 & ! ?ree w float away4 ,no4 #a c1   
:ile peel+1 be transf]r$ to a light wire
 r+ f :i* pap]1 c4 are susp5d$4 ,?is    
description s\nds complicat$1 b aft] a  
little practice ! process c be c>ri$ out
 almo/ ) c]ta9ty 9 f> less "t ?an x     

takes to describe x2 9 fact1 s quickly c
 x be done1 & s simple does x appe>1 t  
no "o w\ld suppose t s _m details _h to 
be att5d$ to4   ,bubbles & ,electricity4
  ,^! exp]im5ts are on ! :ole ! mo/     
difficult to p]=m successfully4 ,!      
foll[+ details %\ld be suffici5t to     
prev5t failure4 ,two r+s are =m$ at !   
end ( a pair ( wires ab\t six in*es long
 9 ! /raight "p4 ,ab\t "o in* at !      
opposite end f ! r+ is turn$ d[n at a "r
 angle4 ,^! turn$-d[n ends re/ 9 two    
holes drill$ v]tically 9 a non-conductor
 su* z ebonite1 ab\t two or ?ree in*es  
ap>t4 ,!n if all is "r ! two r+s are    
horizontal & at ! same level1 & !y may  
be mov$ t[>ds or away f "o ano!r4       
,sep>ate !m a few in*es1 & bl[ a bubble 
above or bel[ ea*1 mak+ !m ne>ly ! same 
size4 ,!n br+ ! two r+s ne>] toge!r     
until ! bubbles j1 & only j1 re/ aga9/  
"o ano!r4 ,?\gh !y may be hamm]$ toge!r 
)\t jo9+1 !y w n rema9 long re/+ 9 ?is  
position1 z ! convex surfaces c readily 
squeeze out ! air4 ,! ebonite %\ld n be 

p]fectly w>m & dry1 = x is !n sure to be
 electrifi$1 & ?is w give tr\ble4 ,x mu/
 n be wet1 because !n x w conduct1 & !  
seal+-wax w produce no result4 ,if x has
 be5 us$ z ! support = ! r+s = "s ( !   
previ\s exp]im5ts1 x w h be5 suffici5tly
 spla%$ by ! bur/+ ( bubbles to be 9 !  
be/ condition4 ,x mu/1 h[ev]1 be well   
wip$ occasionally4  ,a /ick ( seal+-wax 
%\ld be held 9 read9ess "u ! arm1 9 a   
fold or two ( dry flannel or fur4 ,if ! 
wax is v /rongly electrifi$1 x is apt to
 be f> too p[]ful1 & to cause ! bubbles1
 :5 x is pres5t$ to !m1 to de/roy ea*   
o!r4 ,a feeble electrification is       
suffici5t2 !n ! in/ant x is expos$ !    
bubbles coalesce4 ,! wax may be br\ght s
 ne> "o bubble 9 :i* ano!r "o is re/+1 t
 x pulls !m to "o side1 b ! inn] "o is  
scre5$ f electrical action by ! out] "o4
 ,x is important n to br+ ! wax v ne>1 z
 9 t case ! bubble w be pull$ s f> z to 
t\* x1 & s be brok54 ,! wett+ ( ! wax w 
make fur!r electrification v unc]ta94 ,9
 %[+ ! diff]5ce betwe5 an inn] & an out]

 bubble1 ! same rem>ks ) reg>d to undue 
pressure1 electrification1 or loss ( "t 
apply4 ,i h g5]ally f\nd t x is         
advisable 9 ?is exp]im5t n to dra9 !    
drops f bo? ! bubbles1 z _! weight seems
 to /eady !m2 ! ext]nal bubble may be   
dra9$1 & if x is n too l>ge1 ! process (
 electrically jo9+ ! out] bubbles1 )\t  
injury to ! inn] "o1 may be repeat$ _m  
times4 ,i once caus$ eight or n9e s+le  
bubbles to unite ) ! out] "o ( a pair 9 
succession be=e x became too unwieldy = 
m accessions to be possible4         99 
99       99       99       99  ,x w\ld  
be go+ outside my subject to say any?+  
ab\t ! managem5t ( lant]ns4 ,i may1     
h[ev]1 /ate t :ile ! exp]im5ts ) ! small
 bubbles are be/ project$ ) a l5s ^u !  
scre51 ! l>g] bubbles describ$ 9 ! la/  
lecture c only be project$ by _! %ad[s4 
,= ?is purpose ! cond5s+ l5s is remov$1 
& ! b>e light alone made use (4 ,an     
electric arc is f> pref]able to a       
lime-light1 bo? because ! %ad[s are     
%>p]1 & because ! col\rs are s mu* m    

brilliant4 ,no oil lamp w\ld answ]1 ev5 
if ! light 7 suffici5t 9 quantity1      
because ! flame w\ld be f> too l>ge to  
ca/ a %>p %ad[4  ,9 ^! h9ts1 :i* h 9    
!mselves requir$ a r =midable *apt]1 ,i 
h giv5 all ! details1 s f> z ,i am able1
 :i* a consid]able exp]i5ce has %[n to  
be necess>y = ! successful p]=mance or !
 exp]im5ts 9 public4 ,! h9ts w ,i hope  
mat]ially assi/ ^? :o are n 9 ! habit ( 
c>ry+ out exp]im5ts1 b :o may wi% to    
p]=m !m = _! own satisfaction4 ,?\gh p  
:o are n exp]im5tali/s may consid] t !  
h9ts are ov]burd5$ ) detail1 x is       
probable t 9 repeat+ ! exp]im5ts !y w   
f9d "h & !re1 9 spite ( all my c>e to   
provide aga9/ un=ese5 difficulties1 t m 
detail w\ld h be5 desirable4  ,?\gh x is
 unusual to conclude su* a book z ?is ) 
! fulle/ directions = c>ry+ out !       
exp]im5ts describ$1 ,i believe t !      
innovation 9 ! pres5t in/ance is good1 m
 especially because _m ( ! exp]im5ts    
require none ( ! elaborate app>atus :i* 
s (t5 is necess>y4   ,,! ,,end4  ,ri*>d 

,clay  ,sons1 ,limit$1 ,london  ,bungay4
  ,illu/ration3 ,fig4 #ce  ,,?aumatrope 
= %[+ ! =mation & oscillation ( drops4