Evening public ledger. [volume] (Philadelphia [Pa.]) 1914-1942, 1922-11-25
E,1gland's Yard Shrinks

L ScIentlHr 'lrclcS lntelS pPcnuS" OF the
discovery that the House Of Commons
standard yard and standard pound have
changed in size and weight with the years.
The yard Is something like one ten thou.
randth Of an inch shorter than it ought to
b. and the pound is nearly three one thou.
sandth. Of n grain lighter.
1ntinitcsimnl changes. these. in popular
estimation. but vastly important from the
scientific viewpoint. \ tucuating yard or
a Huctuating pound or Il hurtunting second
or hour Is inconrri'nbIc TO the man who's.
whole III" rs science. IL d"r>n T. matter that
III" n"r.u',"n 'S "'l" ,''! ,n3iS;'h mum ~ an
inch: one tel'inillionth would be sufficient
cause for "n"nsincss: There must be- stand.
ar"H IN science ana 'hcsc STANDARDS must
be exact
TNiiE 'ntrrfero'n''"r will measure dis.
l. tan"r SO small that tho most powerful
micro>cor" could not detect a million Of
thcn. IN fact. the human mind cannot
really conceive of such infinitely tiny unit,.
Yet sc'"nr" measures them and deals witt
them in calculations.
That may seem like drawing ,hc lin.
pretty line. but it is rough work com,ared
I" the dcirnry required by some mcasmre.
ments in science. This necessity has led
l." ~" invention Of one of ,h" most mar.
Vicious OF all scientific instruments, Tho
ihtrricr"nlctrr.
let us assume that two LITTLE motor.
- hp
We neat the pXhnusts OF their engines from
a distance. There Is n peculiar phcnor,pnov
bout the sound. Every now and thcn tM
EXPLOSIONS wi occur at exactly tic ssus
| then be nearly twice as loud us ri,bcr er.
rinSlon alone.
!'rad'lall" III" sounds will separate IL
| @ @".ht OF 'imr until they arc Il half beat
! alhrI and then the sound will not h
hfHriE :" loud.
This is caused BY the fact TINT tho on.
| gin"S are slightly different in their speeds
| n minute and tho other rms 40 Tho dii.
ference. or iiity n minute win hc ,h" u"m.
! bcr cf timcs iLcv viii n., -. -. w on ~, nma
seem to explode ,orciher " '''' '"'
You will notice thr s,mo rhc,omonon
when two fnrinrv whistin, .ro r'' I hln"mS
There viii unrrar IN I,: n hcat ar nnt" "n,"s. hs.
tween ,hcm--n pul.iny NJ snunl ,h,, win
come in like "A wave and N, m,,,rh louder
| than ni,L.r y,h;.,Io ,inmn ~ ,I ' ,hn ,;l
| faI,' awuv and hc f,i"tor "t"'' ""'' '"'" VI"
Whistles rnu>" vihm'tinn, ,r ,,.o,o, IN ,b.
uir. 4 whistle thnt r,,,.cs , cor,,in mu,n.
! hey of Vibrations - second vii, ,n,rj m.
! uo,.. and onn,hcr ,hr,, i,,,, ",' ,o'h", ls,,
! or moro ,,iil .ounJ nnn,Lnr
Eui thrr. viii Ln n,n m,,i,,, ,o,.,,.r,,, /,
| rrlntj,ushln v,ith ,to J;h.,n'' l., rnmhs,
~ ,i'n 49, ~ T"'n VI" ways o' tue wv
cnr!, nthrr and mnkr ~ hi"yrr wn,r and al
| all other times mo v,',rs vii, iuIrrip,c 10
Il greater or lc.. cy,nnt ,n,Il tho rniiwa,
point whore they viii hive n tendency
almost 10 n,u,rnliyo ",r,, "thcr
J>IlE intrrfcrui,c,., d,cs ms, ,liS ver,
hin, with ,L, .Lnr,',', ,i.i, y'' .',,n. ,b.,
~, knn,. - IL ,,i '.H. '.S"' ""'r h,,,.t
tho, i, ,,,tu,j,,. ,"mI a"r i''a no,n,
,cuinst ,L" ""', .ni ',t ~ ..bast sS;
rnIc'' oi,.. -. ,I,n ,,'', m 4. "'n ~" ,ocord
h, vhir,, ,hoir ,r"'ni" "' '',itrN ,ts TSst
| "i;. -, ,h ~, ~ "n "'"r '". ~,
! nmnnu o ,''"' i''I"'''E ~ 'nn ,i n
'ir>, n @ "' is w., N,nM 'n. sios" li.os,m.
lnr,b nr en-" nr ,hc," '"u " cras,
t" tho Tho II nrxI' Nv VI '"''', "'"'''N Il N"'' ''''