17-spring-第1节

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　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　Spring



　　　　The　opening　of　large　tracts　by　the　ice…cutters　commonly　causes　a

pond　to　break　up　earlier；　for　the　water；　agitated　by　the　wind；　even

in　cold　weather；　wears　away　the　surrounding　ice。　　But　such　was　not

the　effect　on　Walden　that　year；　for　she　had　soon　got　a　thick　new

garment　to　take　the　place　of　the　old。　　This　pond　never　breaks　up　so

soon　as　the　others　in　this　neighborhood；　on　account　both　of　its

greater　depth　and　its　having　no　stream　passing　through　it　to　melt　or

wear　away　the　ice。　　I　never　knew　it　to　open　in　the　course　of　a

winter；　not　excepting　that　of　'52…3；　which　gave　the　ponds　so　severe

a　trial。　　It　commonly　opens　about　the　first　of　April；　a　week　or　ten

days　later　than　Flint's　Pond　and　Fair　Haven；　beginning　to　melt　on

the　north　side　and　in　the　shallower　parts　where　it　began　to　freeze。

It　indicates　better　than　any　water　hereabouts　the　absolute　progress

of　the　season；　being　least　affected　by　transient　changes　of

temperature。　　A　severe　cold　of　a　few　days　duration　in　March　may　very

much　retard　the　opening　of　the　former　ponds；　while　the　temperature

of　Walden　increases　almost　uninterruptedly。　　A　thermometer　thrust

into　the　middle　of　Walden　on　the　6th　of　March；　1847；　stood　at　32x；

or　freezing　point；　near　the　shore　at　33x；　in　the　middle　of　Flint's

Pond；　the　same　day；　at　32＋x；　at　a　dozen　rods　from　the　shore；　in

shallow　water；　under　ice　a　foot　thick；　at　36x。　　This　difference　of

three　and　a　half　degrees　between　the　temperature　of　the　deep　water

and　the　shallow　in　the　latter　pond；　and　the　fact　that　a　great

proportion　of　it　is　comparatively　shallow；　show　why　it　should　break

up　so　much　sooner　than　Walden。　　The　ice　in　the　shallowest　part　was

at　this　time　several　inches　thinner　than　in　the　middle。　　In

midwinter　the　middle　had　been　the　warmest　and　the　ice　thinnest

there。　　So；　also；　every　one　who　has　waded　about　the　shores　of　the

pond　in　summer　must　have　perceived　how　much　warmer　the　water　is

close　to　the　shore；　where　only　three　or　four　inches　deep；　than　a

little　distance　out；　and　on　the　surface　where　it　is　deep；　than　near

the　bottom。　　In　spring　the　sun　not　only　exerts　an　influence　through

the　increased　temperature　of　the　air　and　earth；　but　its　heat　passes

through　ice　a　foot　or　more　thick；　and　is　reflected　from　the　bottom

in　shallow　water；　and　so　also　warms　the　water　and　melts　the　under

side　of　the　ice；　at　the　same　time　that　it　is　melting　it　more

directly　above；　making　it　uneven；　and　causing　the　air　bubbles　which

it　contains　to　extend　themselves　upward　and　downward　until　it　is

completely　honeycombed；　and　at　last　disappears　suddenly　in　a　single

spring　rain。　　Ice　has　its　grain　as　well　as　wood；　and　when　a　cake

begins　to　rot　or　〃comb；〃　that　is；　assume　the　appearance　of

honeycomb；　whatever　may　be　its　position；　the　air　cells　are　at　right

angles　with　what　was　the　water　surface。　　Where　there　is　a　rock　or　a

log　rising　near　to　the　surface　the　ice　over　it　is　much　thinner；　and

is　frequently　quite　dissolved　by　this　reflected　heat；　and　I　have

been　told　that　in　the　experiment　at　Cambridge　to　freeze　water　in　a

shallow　wooden　pond；　though　the　cold　air　circulated　underneath；　and

so　had　access　to　both　sides；　the　reflection　of　the　sun　from　the

bottom　more　than　counterbalanced　this　advantage。　　When　a　warm　rain

in　the　middle　of　the　winter　melts　off　the　snow…ice　from　Walden；　and

leaves　a　hard　dark　or　transparent　ice　on　the　middle；　there　will　be　a

strip　of　rotten　though　thicker　white　ice；　a　rod　or　more　wide；　about

the　shores；　created　by　this　reflected　heat。　　Also；　as　I　have　said；

the　bubbles　themselves　within　the　ice　operate　as　burning…glasses　to

melt　the　ice　beneath。

　　　　The　phenomena　of　the　year　take　place　every　day　in　a　pond　on　a

small　scale。　　Every　morning；　generally　speaking；　the　shallow　water

is　being　warmed　more　rapidly　than　the　deep；　though　it　may　not　be

made　so　warm　after　all；　and　every　evening　it　is　being　cooled　more

rapidly　until　the　morning。　　The　day　is　an　epitome　of　the　year。　　The

night　is　the　winter；　the　morning　and　evening　are　the　spring　and

fall；　and　the　noon　is　the　summer。　　The　cracking　and　booming　of　the

ice　indicate　a　change　of　temperature。　　One　pleasant　morning　after　a

cold　night；　February　24th；　1850；　having　gone　to　Flint's　Pond　to

spend　the　day；　I　noticed　with　surprise；　that　when　I　struck　the　ice

with　the　head　of　my　axe；　it　resounded　like　a　gong　for　many　rods

around；　or　as　if　I　had　struck　on　a　tight　drum…head。　　The　pond　began

to　boom　about　an　hour　after　sunrise；　when　it　felt　the　influence　of

the　sun's　rays　slanted　upon　it　from　over　the　hills；　it　stretched

itself　and　yawned　like　a　waking　man　with　a　gradually　increasing

tumult；　which　was　kept　up　three　or　four　hours。　　It　took　a　short

siesta　at　noon；　and　boomed　once　more　toward　night；　as　the　sun　was

withdrawing　his　influence。　　In　the　right　stage　of　the　weather　a　pond

fires　its　evening　gun　with　great　regularity。　　But　in　the　middle　of

the　day；　being　full　of　cracks；　and　the　air　also　being　less　elastic；

it　had　completely　lost　its　resonance；　and　probably　fishes　and

muskrats　could　not　then　have　been　stunned　by　a　blow　on　it。　　The

fishermen　say　that　the　〃thundering　of　the　pond〃　scares　the　fishes

and　prevents　their　biting。　　The　pond　does　not　thunder　every　evening；

and　I　cannot　tell　surely　when　to　expect　its　thundering；　but　though　I

may　perceive　no　difference　in　the　weather；　it　does。　　Who　would　have

suspected　so　large　and　cold　and　thick…skinned　a　thing　to　be　so

sensitive？　　Yet　it　has　its　law　to　which　it　thunders　obedience　when

it　should　as　surely　as　the　buds　expand　in　the　spring。　　The　earth　is

all　alive　and　covered　with　papillae。　　The　largest　pond　is　as

sensitive　to　atmospheric　changes　as　the　globule　of　mercury　in　its

tube。

　　　　One　attraction　in　coming　to　the　woods　to　live　was　that　I　should

have　leisure　and　opportunity　to　see　the　Spring　come　in。　　The　ice　in

the　pond　at　length　begins　to　be　honeycombed；　and　I　can　set　my　heel

in　it　as　I　walk。　　Fogs　and　rains　and　warmer　suns　are　gradually

melting　the　snow；　the　days　have　grown　sensibly　longer；　and　I　see　how

I　shall　get　through　the　winter　without　adding　to　my　wood…pile；　for

large　fires　are　no　longer　necessary。　　I　am　on　the　alert　for　the

first　signs　of　spring；　to　hear　the　chance　note　of　some　arriving

bird；　or　the　striped　squirrel's　chirp；　for　his　stores　must　be　now

nearly　exhausted；　or　see　the　woodchuck　venture　out　of　his　winter

quarters。　　On　the　13th　of　March；　after　I　had　heard　the　bluebird；

song　sparrow；　and　red…wing；　the　ice　was　still　nearly　a　foot　thick。

As　the　weather　grew　warmer　it　was　not　sensibly　worn　away　by　the

water；　nor　broken　up　and　floated　off　as　in　rivers；　but；　though　it

was　completely　melted　for　half　a　rod　in　width　about　the　shore；　the

middle　was　merely　honeycombed　and　saturated　with　water；　so　that　you

could　put　your　foot　through　it　when　six　inches　thick；　but　by　the

next　day　evening；　perhaps；　after　a　warm　rain　followed　by　fog；　it

would　have　wholly　disappeared；　all　gone　off　with　the　fog；　spirited

away。　　One　year　I　went　across　the　middle　only　five　days　before　it

disappeared　entirely。　　In　1845　Walden　was　first　completely　open　on

the　1st　of　April；　in　'46；　the　25th　of　March；　in　'47；　the　8th　of

April；　in　'51；　the　28th　of　March；　in　'52；　the　18th　of　April；　in　'53；

the　23d　of　March；　in　'54；　about　the　7th　of　April。

　　　　Every　incident　connected　with　the　breaking　up　of　the　rivers　and

ponds　and　the　settling　of　the　weather　is　particularly　interesting　to

us　who　live　in　a　climate　of　so　great　extremes。　　When　the　warmer　days

come；　they　who　dwell　near　the　river　hear　the　ice　crack　at　night　with

a　startling　whoop　as　loud　as　artillery；　as　if　its　icy　fetters　were

rent　from　end　to　end；　and　within　a　few　days　see　it　rapidly　going

out。　　So　the　alligator　comes　out　of　the　mud　with　quakings　of　the

earth。　　One　old　man；　who　has　been　a　close　observer　of　Nature；　and

seems　as　thoroughly　wise　in　regard　to　all　her　operations　as　if　she

had　been　put　upon　the　stocks　when　he　was　a　boy；　and　he　had　helped　to

lay　her　keel　　who　has　come　to　his　growth；　and　can　hardly　acquire

more　of　natural　lore　if　he　should　live　to　the　age　of　Methuselah　

told　me　　and　I　was　surprised　to　hear　him　express　wonder　at　any　of

Nature's　operations；　for　I　thought　that　there　were　no　secrets

between　them　　that　one　spring　day　he　took　his　gun　and　boat；　and

thought　that　he　would　have　a　little　sport　with　the　ducks。　　There　was

ice　still　on　the　meadows；　but　it　was　all　gone　out　of　the　river；　and

he　dropped　down　without　obstruction　from　Sudbury；　where　he　lived；　to

Fair　Haven　Pond；　which　he　found；　unexpectedly；　covered　for　the　most

part　with　a　firm　field　of　ice。　　It　was　a　warm　day；　and　he　was

surprised　to　see　so　great　a　body　of　ice　remaining。　　Not　seeing　any

ducks；　he　hid　his　boat　on　the　north　or　back　side　of　an　island　in　the

pond；　and　then　concealed　himself　in　the　bushes　on　the　south　side；　to

await　them。　　The　ice　was　melted　for　three　or　four　rods　from　the

shore；　and　there　was　a　smooth　and　wa