218 ASTRONOMYANDTHEBIBLE
longitude,andhecanputhisfingerdownandsaythe
shipisrightthere.
Ifhe fears thathischronometer isnotcorrect, he
cantestitbytheclockoftheuniverse.
Nowthereissuchaclock, anditkeepsGreenwich
time, even though the captain is many miles from
England;and he can lookatthe face ofthis clock
anycloudlessnight,andreadthetime,nomatterwhere
heis. Thenifhischronometerhaslostorgained,he
cancorrectitbythegreatclockoftheuniverse. What
dowemeanbyallthis?
Theface ofthisgiganticclock is in factthe face
ofthestarryheavens. Thenumbersonthedial are,
bythissamefigureofspeech,thetwinklingstars;and
thehandthatmovesover thedialisnothingbutthe
moonitself.
When thecaptain desiresto test hischronometer,
hemeasuresthedistanceofthemoon fromacertain
neighboring star. He discovers, perhaps, that the
moon is three degrees from some star; and in the
nautical almanac,he finds theGreenwich time when
themoonisthreedegreesfromthisstar. Comparing
thiswiththeindicationsofthechronometer, hefinds
therequiredcorrection.
There areotherindicationswhichcauseusto call
theuniversea clock. Onallclocks,thereareseveral
means by which weascertainthe different divisions
oftime. Thereisanhourhand,a minutehand,and
asecond hand. Onedivision measuresfive minutes
bythebighand,andonehourbythesmallhand. One
revolution ofthe dialby thebig handmeasures an