a journey in other worlds-第6章

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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continent；　and　in　some　cases　have　almost　superseded　irrigation。　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；　and
stationary　and　portable　motors；　for　heating　the　cables　laid　along
the　bottom　of　our　canals　to　prevent　their　freezing　in　winter；　and
for　almost　every　conceivable　purpose。　　Sometimes　a　man　has　a
windmill　on　his　roof　for　light　and　heat；　then；　the　harder　the
wintry　blasts　may　blow　the　brighter　and　warmer　becomes　the　house；
the　current　passing　through　a　storage　battery　to　make　it　more
steady。　　The　operation　of　our　ordinary　electric　railways　is　very
simple：　the　current　is　taken　from　an　overhead；　side；　or
underneath　wire；　directly　through　the　air；　without　the
intervention　of　a　trolley；　and　the　fast　cars；　for　they　are　no
longer　run　in　trains；　make　five　miles　a　minute。　　The　entire
weight　of　each　car　being　used　for　its　own　traction；　it　can　ascend
very　steep　grades；　and　can　attain　high　speed　or　stop　very
quickly。
　　　
〃Another　form　is　the　magnetic　railway；　on　which　the　cars　are
wedge…shaped　at　both　ends；　and　moved　by　huge　magnets　weighing
four　thousand　tons　each；　placed　fifty　miles　apart。　　On　passing　a
magnet；　the　nature　of　the　electricity　charging　a　car　is
automatically　changed　from　positive　to　negative；　or　vice　versa；
to　that　of　the　magnet　just　passed；　so　that　it　repels　while　the
next　attracts。　　The　successive　magnets　are　charged　oppositely；
the　sections　being　divided　halfway　between　by　insulators；　the
nature　of　the　electricity　in　each　section　being　governed　by　the
charge　in　the　magnet。　　To　prevent　one　kind　of　electricity　from
uniting　with　and　neutralizing　that　in　the　next　section　by　passing
through　the　car　at　the　moment　of　transit；　there　is　a　〃dead
stretch〃　of　fifty　yards　with　rails　not　charged　at　all　between　the
sections。　　This　change　in　the　nature　of　the　electricity　is
repeated　automatically　every　fifty　miles；　and　obviates　the
necessity　of　revolving　machinery；　the　rails　aiding　communication。

〃Magnetism　being　practically　as　instantaneous　as　gravitation；　the
only　limitations　to　speed　are　the　electrical　pressure　at　the
magnets；　the　resistance　of　the　air；　and　the　danger　of　the　wheels
bursting　from　centrifugal　force。　　The　first　can　seemingly　be
increased　without　limit；　the　atmospheric　resistance　is　about　to
be　reduced　by　running　the　cars　hermetically　sealed　through　a
partial　vacuum　in　a　steel　and　toughened　glass　tube；　while　the
third　has　been　removed　indefinitely　by　the　use　of　galvanized
aluminum；　which　bears　about　the　same　relation　to　ordinary
aluminum　that　steel　does　to　iron；　and　which　has　twice　the　tensile
strength　and　but　one　third　the　weight　of　steel。　　In　some　cases
the　rails　are　made　turned　in；　so　that　it　would　be　impossible　for
a　car　to　leave　the　track　without　the　road…bed's　being　totally
demolished；　but　in　most　cases　this　is　found　to　be　unnecessary；
for　no　through　line　has　a　curve　on　its　vast　stretches　with　a
radius　of　less　than　half　a　mile。　　Rails；　one　hundred　and　sixty
pounds　to　the　yard；　are　set　in　grooved　steel　ties；　which　in　turn
are　held　by　a　concrete　road…bed　consisting　of　broken　stone　and
cement；　making　spreading　rails　and　loose　ballast　impossible。　　A
large　increase　in　capital　was　necessary　for　these　improvements；
the　elimination　of　curves　being　the　most　laborious　part；
requiring　bridges；　cuttings；　and　embankments　that　dwarf　the
Pyramids　and　would　have　made　the　ancient　Pharaohs　open　their
eyes；　but　with　the　low　rate　of　interest　on　bonds；　the　slight　cost
of　power；　and　great　increase　in　business；　the　venture　was　a
success；　and　we　are　now　in　sight　of　further　advances　that　will
enable　a　traveller　in　a　high　latitude　moving　west　to　keep　pace
with　the　sun；　and；　should　he　wish　it；　to　have　unending　day。〃



　　　　　　　　　　　　　　　　　　　　　　　　　　　CHAPTER　V。

　　　　　　　　　　　　　　　DR。　CORTLANDT'S　HISTORY　CONTINUED。
　　
〃In　marine　transportation　we　have　two　methods；　one　for　freight
and　another　for　passengers。　　The　old…fashioned　deeply　immersed
ship　has　not　changed　radically　from　the　steam　and　sailing　vessels
of　the　last　century；　except　that　electricity　has　superseded　all
other　motive　powers。　　Steamers　gradually　passed　through　the　five
hundred…；　six　hundred…；　and　seven　hundred…foot…long　class；　with
other　dimensions　in　proportion；　till　their　length　exceeded　one
thousand　feet。　　These　were　very　fast　ships；　crossing　the　Atlantic
in　four　and　a　half　days；　and　were　almost　as　steady　as　houses；　in
even　the　roughest　weather。
　　　
〃Ships　at　this　period　of　their　development　had　also　passed
through　the　twin　and　triple　screw　stage　to　the　quadruple；　all
four　together　developing　one　hundred　and　forty　thousand　indicated
horse…power；　and　being　driven　by　steam。　　This；　of　course；
involved　sacrificing　the　best　part　of　the　ship　to　her　engines；
and　a　very　heavy　idle　investment　while　in　port。　　Storage
batteries；　with　plates　composed　of　lead　or　iron；　constantly
increasing　in　size；　had　reached　a　fair　state　of　development　by
the　close　of　the　nineteenth　century。
　　　
〃During　the　second　decade　of　the　twentieth　century　the　engineers
decided　to　try　the　plan　of　running　half　of　a　transatlantic
liner's　screws　by　electricity　generated　by　the　engines　for
driving　the　others　while　the　ship　was　in　port；　this　having　been　a
success　already　on　a　smaller　scale。　　For　a　time　this　plan　gave
great　satisfaction；　since　it　diminished　the　amount　of　coal　to　be
carried　and　the　consequent　change　of　displacement　at　sea；　and
enabled　the　ship　to　be　worked　with　a　smaller　number　of　men。　　The
batteries　could　also；　of　course；　be　distributed　along　the　entire
length；　and　placed　where　space　was　least　valuable。
　　　
〃The　construction　of　such　huge　vessels　called　for　much
governmental　river　and　harbour　dredging；　and　a　ship　drawing
thirty…five　feet　can　now　enter　New　York　at　any　state　of　the　tide。　
For　ocean　bars；　the　old　system　of　taking　the　material　out　to　sea
and　discharging　it　still　survives；　though　a　jet　of　water　from
force…pumps　directed　against　the　obstruction　is　also　often
employed　with　quick　results。　　For　river　work　we　have　discovered　a
better　method。　　All　the　mud　is　run　back；　sometimes　over　a　mile
from　the　river　bank；　where　it　is　used　as　a　fertilizer；　by　means
of　wire　railways　strung　from　poles。　　These　wire　cables　combine　in
themselves　the　functions　of　trolley　wire　and　steel　rail；　and
carry　the　suspended　cars；　which　empty　themselves　and　return
around　the　loop　for　another　load。　　Often　the　removed　material
entirely　fills　small；　saucer…shaped　valleys　or　low　places；　in
which　case　it　cannot　wash　back。　　This　improvement　has　ended　the
necessity　of　building　jetties。
　　　
〃The　next　improvement　in　sea　travelling　was　the　'marine　spider。'　
As　the　name　shows；　this　is　built　on　the　principle　of　an　insect。　
It　is　well　known　that　a　body　can　be　carried　over　the　water　much
faster　than　through　it。　　With　this　in　mind；　builders　at　first
constructed　light　framework　decks　on　large　water…tight　wheels　or
drums；　having　paddles　on　their　circumferences　to　provide　a　hold
on　the　water。　　These　they　caused　to　revolve　by　means　of　machinery
on　the　deck；　but　soon　found　that　the　resistance　offered　to　the
barrel　wheels　themselves　was　too　great。　　They　therefore　made　them
more　like　centipeds　with　large；　bell…shaped　feet；　connected　with
a　superstructural　deck　by　ankle…jointed　pipes；　through　which；
when　necessary；　a　pressure　of　air　can　be　forced　down　upon　the
enclosed　surface　of　water。　　Ordinarily；　however；　they　go　at　great
speed　without　this；　the　weight　of　the　water　displaced　by　the　bell
feet　being　as　great　as　that　resting　upon　them。　　Thus　they　swing
along　like　a　pacing　horse；　except　that　there　are　four　rows　of
feet　instead　of　two；　each　foot　being　taken　out　of　the　water　as　it
is　swung　forward；　the　first　and　fourth　and　second　and　third　rows
being　worked　together。　　Although；　on　account　of　their　size；　which
covers　several　acres；　they　can　go　in　any　water；　they　give　the
best　results　on　Mediterraneans　and　lakes　that　are　free　from　ocean
rollers；　and；　under　favourable　conditions；　make　better　speed　than
the　nineteenth…century　express　trains；　and；　of　course；　going
straight　as　the　crow　flies；　and　without　stopping；　they　reach　a
destination　in　considerably　shorter　time。
　　　
Some　passengers　and　express　packages　still　cross　the　Atlantic　on
'spiders；'　but　most　of　these　light　cargoes　go　in　a　far　pleasanter
and　more　rapid　way。　　The　deep…displacement　vessels；　for　heavy
freight；　make　little　better　speed　than　was　made　by　the　same　class
a　hundred　years　ago。　　But　they　are　also　run　entirely　by
electricity；　largely　supplied　by　wind；　and　by　the　tide　turning
their　motors；　which　become　dynamos　while　at　anchor　in　any　stream。　
They　therefore　need　no　bulky　boilers；　engines；　sails；　or
coal…bunkers；　and　consequently　can　carry　unprecedentedly　large
cargoes　with　comparatively　small　crews。　　The　officers　on　the
bridge　and　the　men　in　the　crow's　nestthe　way　to　which　is　by　a
ladder　INSIDE　the　mast；　to　protect　the　climber　from　the
weatherare　about　all　that　is　needed；　while　disablement　is　made
practically　impossible；　by　having　four　screws；　each　with　its　own
set　of　automatically　lubricating　motors。
　　　
〃This　change；　like　other　labour…saving　appliances；　at　first
resulted　in　laying　off　a　good　many　men；　the　least　satisfactory
being　the　first　to　go；　but　the　increase　in　business　was　so　great
that　the　intelligent　men　were　soon　reemployed　as　officers　at
higher　rates　of　pay　and　more　interesting　work　than　before；　while
they　as　consumers　were　benefited　as　much　as　any　one　else　by　the
decreased　cost　of　production　and　transportation。
　　　
〃With　a　view　to　facilitating　interchange　still　further；　our
Government　has　gradually　completed　the　double　coast…line　that
Nature　gave　us　in　part。　　This　was　done　by　connecting　islands
separated　from　shore　by　navigable　water；　and　leaving　openings　for
ingress　and　exit　but　a　few　hundred　yards　wide。　　The　breakwaters
required　to　do　this　were　built　with　cribbing　of　incorrodible
metal；　affixed　to　deeply　driven　metallic　piles；　and　filled　with
stones　along　coasts　where　they　were　found　in　abundance　or　excess。　
This；　while　clearing　many　fields　and　improving　them　for
cultivation；　provided　just　the　needed　material；　since　irregular
stones　bind　together　firmly；　and；　while　also　insoluble；　combine
considerable　bulk　with　weight。　　Sou