96 ASTRONOMYANDTHEBIBLE
thesamework,theproductsoftheexplosionmustby
some powerbe decomposed, and theatoms replaced
inthesamerelationas beforethefiringofthegun;
andthisprocessismechanicallyanalogoustothelift-
ingoffallenweightsandplacingthemuponelevated
shelves, orhangingthemfromhooks,ready todrop
againwhentheoccasionmayrequire.
"Preciselythesamething istrue oftheheatpro-
ducedbythecombustionofordinary fuel:Itisdueto
thecollapseofmolecules,forthemostpartofoxygen
on oneside,and carbonand hydrogenon theother,
whichhavebeenseparatedandbuiltupintostructures
bytheactionofsomelaboringpower.
"Thesamecanbesaidofanimalpower,forallin-
vestigationgoesto showthatin amechanical sense
thebodyof an animalis only averyingenious and
effective machine,by means of which theliving in-
habitantwhich controlsit canutilizethe energyde-
rivedfromthefoodtakenintothestomach. Thebody,
regarded as a mechanism, is onlya food engine in
whichthestomachandlungsstandforthefurnaceand
boilerofa steamengine,thenervoussystem forthe
valvegear, andthe muscles forthecylinder. How
thepersonality within, which wills and acts, is put
into relationwiththisvalve gearsoas to determine
themovements of thebody it resides in, is the in-
scrutablemysteryoflife;the factsinthecase, how-
ever,beingnolessfactsbecauseinexplicable.
"Andnow,whenwecometoinquireforthesource
oftheenergywhichliftsthewater fromtheseato
themountaintop,whichdecomposesthecarbonicacid