industrial biography-第71章

按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！



the　cost　of　planing　does　not　amount　to　more　than　three…halfpence　the

square　foot。



The　excellence　of　Mr。　Clement's　tools；　and　his　well…known　skill　in

designing　and　executing　work　requiring　unusual　accuracy　and　finish；

led　to　his　being　employed　by　Mr。　Babbage　to　make　his　celebrated

Calculating　or　Difference　Engine。　　The　contrivance　of　a　machine　that

should　work　out　complicated　sums　in　arithmetic　with　perfect

precision；　was；　as　may　readily　be　imagined；　one　of　the　most　difficult

feats　of　the　mechanical　intellect。　　To　do　this　was　in　an　especial

sense　to　stamp　matter　with　the　impress　of　mind；　and　render　it

subservient　to　the　highest　thinking　faculty。　　Attempts　had　been　made

at　an　early　period　to　perform　arithmetical　calculations　by　mechanical

aids　more　rapidly　and　precisely　than　it　was　possible　to　do　by　the

operations　of　the　individual　mind。　　The　preparation　of　arithmetical

tables　of　high　numbers　involved　a　vast　deal　of　labour；　and　even　with

the　greatest　care　errors　were　unavoidable　and　numerous。　　Thus　in　a

multipltcation…table　prepared　by　a　man　so　eminent　as　Dr。　Hutton　for

the　Board　of　Longitude；　no　fewer　than　forty　errors　were　discovered　in

a　single　page　taken　at　random。　　In　the　tables　of　the　Nautical　Almanac；

where　the　greatest　possible　precision　was　desirable　and　necessary；

more　than　five　hundred　errors　were　detected　by　one　person；　and　the

Tables　of　the　Board　of　Longitude　were　found　equally　incorrect。　　But

such　errors　were　impossible　to　be　avoided　so　long　as　the　ordinary

modes　of　calculating；　transcribing；　and　printing　continued　in　use。



The　earliest　and　simplest　form　of　calculating　apparatus　was　that

employed　by　the　schoolboys　of　ancient　Greece；　called　the　Abacus；

consisting　of　a　smooth　board　with　a　narrow　rim；　on　which　they　were

taught　to　compute　by　means　of　progressive　rows　of　pebbles；　bits　of

bone　or　ivory；　or　pieces　of　silver　coin；　used　as　counters。　　The　same

board；　strewn　over　with　sand；　was　used　for　teaching　the　rudiments　of

writing　and　the　principles　of　geometry。　　The　Romans　subsequently

adopted　the　Abacus；　dividing　it　by　means　of　perpendicular　lines　or

bars；　and　from　the　designation　of　calculus　which　they　gave　to　each

pebble　or　counter　employed　on　the　board；　we　have　derived　our　English

word　to　calculate。　　The　same　instrument　continued　to　be　employed

during　the　middle　ages；　and　the　table　used　by　the　English　Court　of

Exchequer　was　but　a　modified　form　of　the　Greek　Abacus；　the　chequered

lines　across　it　giving　the　designation　to　the　Court；　which　still

survives。　　Tallies；　from　the　French　word　tailler　to　cut；　were　another

of　the　mechanical　methods　employed　to　record　computations；　though　in

a　very　rude　way。　　Step　by　step　improvements　were　made；　the　most

important　being　that　invented　by　Napier　of　Merchiston；　the　inventor

of　logarithms；　commonly　called　Napier's　bones；　consisting　of　a　number

of　rods　divided　into　ten　equal　squares　and　numbered；　so　that　the

whole　when　placed　together　formed　the　common　multiplication　table。　　By

these　means　various　operations　in　multiplication　and　division　were

performed。　　Sir　Samuel　Morland；　Gunter；　and　Lamb　introduced　other

contrivances；　applicable　to　trigonometry；　Gunter's　scale　being　still

in　common　use。　　The　calculating　machines　of　Gersten　and　Pascal　were　of

a　different　kind；　working　out　arithmetical　calculations　by　means　of

trains　of　wheels　and　other　arrangements；　and　that　contrived　by　Lord

Stanhope　for　the　purpose　of　verifying　his　calculations　with　respect

to　the　National　Debt　was　of　like　character。　　But　none　of　these　will

bear　for　a　moment　to　be　compared　with　the　machine　designed　by　Mr。

Babbage　for　performing　arithmetical　calculations　and　mathematical

analyses；　as　well　as　for　recording　the　calculations　when　made；

thereby　getting　rid　entirely　of　individual　error　in　the　operations　of

calculation；　transcription；　and　printing。



The　French　government；　in　their　desire　to　promote　the　extension　of

the　decimal　system；　had　ordered　the　construction　of　logarithmical

tables　of　vast　extent；　but　the　great　labour　and　expense　involved　in

the　undertaking　prevented　the　design　from　being　carried　out。　　It　was

reserved　for　Mr。　Babbage　to　develope　the　idea　by　means　of　a　machine

which　he　called　the　Difference　Engine。　　This　machine　is　of　so

complicated　a　character　that　it　would　be　impossible　for　us　to　give

any　intelligible　description　of　it　in　words　。　　Although　Dr。　Lardner

was　unrivalled　in　the　art　of　describing　mechanism；　he　occupied

twenty…five　pages　of　the　'Edinburgh　Review'　（vol。59）　in　endeavouring

to　describe　its　action；　and　there　were　several　features　in　it　which

he　gave　up　as　hopeless。　　Some　parts　of　the　apparatus　and　modes　of

action　are　indeed　extraordinary　and　perhaps　none　more　so　than　that

for　ensuring　accuracy　in　the　calculated　results；the　machine

actually　correcting　itself；　and　rubbing　itself　back　into　accuracy；

when　the　disposition　to　err　occurs；　by　the　friction　of　the　adjacent

machinery！　　When　an　error　is　made；　the　wheels　become　locked　and　refuse

to　proceed；　thus　the　machine　must　go　rightly　or　not　at　all；an

arrangement　as　nearly　resembling　volition　as　anything　that　brass　and

steel　are　likely　to　accomplish。



This　intricate　subject　was　taken　up　by　Mr。　Babbage　in　1821；　when　he

undertook　to　superintend　for　the　British　government　the　construction

of　a　machine　for　calculating　and　printing　mathematical　and

astronomical　tables。　　The　model　first　constructed　to　illustrate　the

nature　of　his　invention　produced　figures　at　the　rate　of　44　a　minute。

In　1823　the　Royal　Society　was　requested　to　report　upon　the　invention；

and　after　full　inquiry　the　committee　recommended　it　as　one　highly

deserving　of　public　encouragement。　　A　sum　of　1500L。　was　then　placed　at

Mr。　Babbage's　disposal　by　the　Lords　of　the　Treasury　for　the　purpose

of　enabling　him　to　perfect　his　invention。　　It　was　at　this　time　that　he

engaged　Mr。　Clement　as　draughtsman　and　mechanic　to　embody　his　ideas

in　a　working　machine。　　Numerous　tools　were　expressly　contrived　by　the

latter　for　executing　the　several　parts；　and　workmen　were　specially

educated　for　the　purpose　of　using　them。　　Some　idea　of　the　elaborate

character　of　the　drawings　may　be　formed　from　the　fact　that　those

required　for　the　calculating　machinery　alonenot　to　mention　the

printing　machinery；　which　was　almost　equally　elaboratecovered　not

less　than　four　hundred　square　feet　of　surface！　　The　cost　of　executing

the　calculating　machine　was　of　course　very　great；　and　the　progress　of

the　work　was　necessarily　slow。　　The　consequence　was　that　the

government　first　became　impatient；　and　then　began　to　grumble　at　the

expense。　　At　the　end　of　seven　years　the　engineer's　bills　alone　were

found　to　amount　to　nearly　7200L。；　and　Mr。　Babbage's　costs　out　of

pocket　to　7000L。　more。　　In　order　to　make　more　satisfactory　progress；

it　was　determined　to　remove　the　works　to　the　neighbourhood　of　Mr。

Babbage's　own　residence；　but　as　Clement's　claims　for　conducting　the

operations　in　the　new　premises　were　thought　exorbitant；　and　as　he

himself　considered　that　the　work　did　not　yield　him　the　average　profit

of　ordinary　employment　in　his　own　trade；　he　eventually　withdrew　from

the　enterprise；　taking　with　him　the　tools　which　he　had　constructed

for　executing　the　machine。　　The　government　also　shortly　after　withdrew

from　it；　and　from　that　time　the　scheme　was　suspended；　the　Calculating

Engine　remaining　a　beautiful　but　unfinished　fragment　of　a　great　work。

Though　originally　intended　to　go　as　far　as　twenty　figures；　it　was

only　completed　to　the　extent　of　being　capable　of　calculating　to　the

depth　of　five　figures；　and　two　orders　of　differences；　and　only　a

small　part　of　the　proposed　printing　machinery　was　ever　made。　　The

engine　was　placed　in　the　museum　of　King's　College　in　1843；　enclosed

in　a　glass　case；　until　the　year　1862；　when　it　was　removed　for　a　time

to　the　Great　Exhibition；　where　it　formed　perhaps　the　most　remarkable

and　beautifully　executed　piece　of　mechanism　the　combined　result　of

intellectual　and　mecha