216 ASTRONOMYANDTHEBIBLE
processbekeptupaslongasthemindcanwork. But
atnotimehavewebeenabletoconceiveofduration
asnotexisting. The mind canconceive ofduration
onlyaseternal,stretchingbackforever,andstretching
intothefutureforever,without"beginningofdays."
Butwhiledurationcannotbelimitedbyanybegin-
ningorend,itcanbemeasuredasitflows. Thatwhich
measuresduration, wecall a clock or awatch or a
chronometer, the last wordmeaning a measurer of
time. When we studythe heavens as ifthey were
somegigantic clock,we findalmostapromise ofin-
finite duration. And this idea ofthe universe as a
clockisnotamerefigureofspeech.
Acaptainis navigatinga ship, we will say, from
LiverpooltoChina. Frequentlyhemustdeterminethe
preciselocationofhisship. Ifhewereunabletodo
this, he could notfind his way across the trackless
ocean. Observationsofthesungivehimhislatitude
andtellhimhislocaltime. Afterhehasobtainedhis
localtime,inordertofindhowfarhehassailedwest,
hehasbuttofindthedifferencebetweenthelocaltime
andtheGreenwichtime, andreduce thistimeto de-
greesand divisionsofa degree. Havingturnedthe
differenceintimeinto degreesand fractionsofade-
gree, he canreadily reduce ittomiles and fractions
ofamile.
Forexample: There are 360 degrees in a circle;
hence 360 degrees measurethe entire circumference
oftheearth. Thenonedegreeisone threehundred
and sixtieth of the circumference of the earth.
Roughly, the circumference of the earth is 25,000