a journey in other worlds-第8部分

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bridges；　tunnels；　and　electric　ferries；　while　the　city's　great
natural　advantages　have　been　enhanced　and　beautified　by　every
ingenious　device。　　No　main　avenue　in　the　newer　sections　is　less
than　two　hundred　feet　wide；　containing　shade　and　fruit　trees；　a
bridle…path；　broad　sidewalks；　and　open　spaces　for　carriages　and
bicycles。　　Several　fine　diagonal　streets　and　breathing…squares
have　also　been　provided　in　the　older　sections；　and　the　existing
parks　have　been　supplemented　by　intermediate　ones；　all　being
connected　by　parkways　to　form　continuous　chains。
　　　
〃The　hollow　masts　of　our　shipsto　glance　at　another　phase　en
passantcarry　windmills　instead　of　sails；　through　which　the　wind
performs　the　work；　of　storing　a　great　part　of　the　energy　required
to　run　them　at　sea；　while　they　are　discharging　or　loading　cargo
in　port；　and　it　can；　of　course；　work　to　better　advantage　while
they　are　stationary　than　when　they　are　running　before　it。　　These
turbines　are　made　entirely　of　light　metal；　and　fold　when　not　in
use；　so　that　only　the　frames　are　visible。　　Sometimes　these　also
fold　and　are　housed；　or　wholly　disappear　within　the　mast。　
Steam…boilers　are　also　placed　at　the　foci　of　huge　concave
mirrors；　often　a　hundred　feet　in　diameter；　the　required　heat
being　supplied　by　the　sun；　without　smoke；　instead　of　by　bulky　and
dirty　coal。　　This　discovery　gave　commercial　value　to　Sahara　and
other　tropical　deserts；　which　are　now　desirable　for　mill…sites
and　for　generating　power；　on　account　of　the　directness　with　which
they　receive　the　sun's　rays　and　their　freedom　from　clouds。　　Mile
after　mile　Africa　has　been　won　for　the　uses　of　civilization；　till
great　stretches　that　were　considered　impassible　are　as　productive
as　gardens。　　Our　condensers；　which　compress；　cool；　and　rarefy
air；　enabling　travellers　to　obtain　water　and　even　ice　from　the
atmosphere；　are　great　aids　in　desert　exploration；　removing
absolutely　the　principal　distress　of　the　ancient　caravan。　　The
erstwhile　'Dark　Continent'　has　a　larger　white　population　now　than
North　America　had　a　hundred　years　ago；　and　has　this　advantage　for
the　future；　that　it　contains　11；600；000　square　miles；　while　North
America　has　less　than　9；000；000。　　Every　part　of　the　globe　will
soon　sustain　about　as　large　and　prosperous　a　population　as　the
amount　of　energy　it　receives　from　the　sun　and　other　sources　will
warrant；　public　debts　and　the　efficiency　of　the　governments　being
the　variable　elements。
　　　
〃The　rabbits　in　Australia；　and　the　far　more　objectionable
poisonous　snakes　in　South　America　and　India；　have　been
exterminated　by　the　capture　of　a　few　dozen　of　the　creatures　in
the　infested　districts；　their　inoculation　with　the　virus　similar
to　the　murus　tiphi；　tuberculosis　or　any　other　contagious…germ
complaint　to　which　the　species　treated　was　particularly
susceptible；　and　the　release　of　these　individuals　when　the
disease　was　seen　to　be　taking　hold。　　The　rabbits　and　serpents
released　at　once　returned　to　their　old　haunts；　carrying　the
plague　far　and　wide。　　The　unfortunate　rabbits　were　greatly
commiserated　even　by　the　medicos　that　wielded　the　death…dealing
syringe；　but；　fortunately　for　themselves；　they　died　easily。　　The
reptiles；　perhaps　on　account　of　the　wider　distribution　of　the
nerve　centres；　had　more　lingering　but　not　painful　deaths；　often；
while　in　articulo　mortis；　leaving　the　holes　with　which　they
seemed　to　connect　their　discomfort；　and　making　a　final　struggle
along　the　ground；　only　to　die　more　quickly　as　a　result　of　their
exertions。　　We　have　applied　this　also　to　the　potato…bug；　locust；
and　other　insect　pests；　no　victim　being　too　small　for　the
ubiquitous；　subtle　germ；　which；　properly　cultivated　and　utilized；
has　become　one　of　man's　best　friends。
　　　
〃We　have　microbe　tests　that　show　us　as　unmistakably　whether　the
germs　of　any　particular　diseaselike　malaria；　typhoid；　or
scarlet　feverare　present　in　the　air；　as　litmus…paper　shows
alkalinity　of　a　solution。　　We　also　inoculate　as　a　preventive
against　these　and　almost　all　other　germ　diseases；　with　the　same
success　that　we　vaccinate　for　smallpox。
　　　
〃The　medicinal　properties　of　all　articles　of　food　are　so　well
understood　also；　that　most　cures　are　brought　about　simply　by
dieting。　　This；　reminds　me　of　the　mistakes　perpetrated　on　a
friend　of　mine　who　called　in　Dr。　Grave…Powders；　one　of　the
old…school　physicians；　to　be　treated　for　insomnia　and　dyspepsia。　
This　old　numskull　restricted　his　diet；　gave　him　huge　doses　of
medicine；　and　decided　most　learnedly　that　he　was　daily　growing
worse。　　Concluding　that　he　had　but　a　short　time　to　live；　my
friend　threw　away　the　nauseating　medicines；　ate　whatever　he　had　a
natural　desire　for；　and　was　soon　as　well　as　everthe　obvious
moral　of　which　is；　that　we　can　get　whatever　treatment　we　need
most　beneficially　from　our　food。　　Our　physicians　are　most　serious
and　thoughtful　men。　　They　never　claim　to　be　infallible；　but　study
scientifically　to　increase　their　knowledge　and　improve　the
methods　of　treatment。　　As　a　result　of　this；　fresh　air；　regular
exercise　for　both　sexes；　with　better　conditions；　and　the
preservation　of　the　lives　of　children　that　formerly　died　by
thousands　from　preventable　causes；　the　physique；　especially　of
women；　is　wonderfully　improved；　and　the　average　longevity　is
already　over　sixty。
　　　
〃Our　social　structure；　to　be　brief；　is　based　on　science；　or　the
conservation　of　energy；　as　the　Greek　philosophers　predicted。　　It
was　known　to　them　that　a　certain　amount　of　power　would　produce
only　a　certain　amount　of　workthat　is；　the　weight　of　a　clock　in
descending　or　a　spring　in　uncoiling　returns　theoretically　the
amount　of　work　expended　in　raising　or　coiling　it；　and　in　no
possible　way　can　it　do　more。　　In　practice；　on　account　of
friction；　etc。；　we　know　it　does　less。　　This　law；　being
invariable；　of　course　limits　us；　as　it　did　Archimedes　and
Pythagoras；　we　have　simply　utilized　sources　of　power　that　their
clumsy　workmen　allowed　to　escape。　　Of　the　four　principal
sourcesfood；　fuel；　wind；　and　tideincluding　harnessed
waterfalls；　the　last　two　do　by　far　the　most　work。　　Much　of　the
electrical　energy　in　every　thunderstorm　is　also　captured　and
condensed　in　our　capacious　storage　batteries；　as　natural　hygeia
in　the　form　of　rain　was　and　is　still　caught　in　our　country
cisterns。　　Every　exposed　place　is　crowned　by　a　cluster　of　huge
windmills　that　lift　water　to　some　pond　or　reservoir　placed　as
high　as　possible。　　Every　stiff　breeze；　therefore；　raises　millions
of　tons　of　water　which　　operate　hydraulic　turbines　as　required。　
Incidentally　these　storage　reservoirs；　by　increasing　the　surface
exposed　to　evaporation　and　the　consequent　rainfall；　have　a　very
beneficial　effect　on　the　dry　regions　in　the　interior　of　the
continent；　and　in　some　cases　have　almost　superseded　irrigation。　
The　windmill　and　dynamo　thus　utilize　bleak　mountain…tops　that；
till　their　discovery；　seemed　to　be　but　indifferent　successes　in
Dame　Nature's　domain。　　The　electricity　generated　by　these；　in
connection　with　that　obtained　by　waterfalls；　tidal　dynamos；
thunderstorms；　chemical　action；　and　slow…moving
quadruple…expansion　steam　engines；　provides　the　power　required　to
run　our　electric　ships　and　water…spiders；　railways；