men of invention and industry-第13节

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at　Glasgow；　on　the　subject。　　In　a　letter　from　Watt　to　Small；

dated　the　30th　September；　1770；　the　former；　after　speaking　of　the

condenser；　and　saying　that　it　cannot　be　dispensed　with；　proceeds：

〃Have　you　ever　considered　a　spiral　oar　for　that　purpose

＇propulsion　of　canal　boats＇；　or　are　you　for　two　wheels？〃　　Watt

added　a　pen…and…ink　drawing　of　his　spiral　oar；　greatly　resembling

the　form　of　screw　afterwards　patented。　　Nothing；　however；　was

actually　done；　and　the　idea　slept。



It　was　revived　again　in　1785；　by　Joseph　Bramah；　a　wonderful

projector　and　inventor。＇5＇　　He　took　out　a　patent；　which　included

a　rotatory　steam…engine；　and　a　mode　of　propelling　vessels　by

means　either　of　a　paddle…wheel　or　a　〃screw　propeller。〃　　This

propeller　was　〃similar　to　the　fly　of　a　smoke…jack〃；　but　there　is

no　account　of　Bramah　having　practically　tried　this　method　of

propulsion。



Austria；　also；　claims　the　honour　of　the　invention　of　the　screw

steamer。　　At　Trieste　and　Vienna　are　statues　erected　to　Joseph

Ressel；　on　whose　behalf　his　countrymen　lay　claim　to　the

invention；　and　patents　for　some　sort　of　a　screw　date　back　as　far

as　1794。



Patents　were　also　taken　out　in　England　and　Americaby　W。

Lyttleton　in　1794；　by　E。　Shorter　in　1799；　by　J。　C。　Stevens；　of

New　Jersey；　in　1804；　by　Henry　James　in　1811but　nothing

practical　was　accomplished。　　Richard　Trevethick；　the　anticipator

of　many　things；　also　took　out　a　patent　in　1815；　and　in　it　he

describes　the　screw　propeller　with　considerable　minuteness。　

Millington；　Whytock；　Perkins；　Marestier；　and　Brown　followed；　with

no　better　results。



The　late　Dr。　Birkbeck；　in　a　letter　addressed　to　the　'Mechanics'

Register；'　in　the　year　1824；　claimed　that　John　Swan；　of　82；

Mansfield　Street；　Kingsland　Road；　London；　was　the　practical

inventor　of　the　screw　propeller。　　John　Swan　was　a　native　of

Coldingham；　Berwickshire。　　He　had　removed　to　London；　and　entered

the　employment　of　Messrs。　Gordon；　of　Deptford。　　Swan　fitted　up　a

boat　with　his　propeller；　and　tried　it　on　a　sheet　of　water　in　the

grounds　of　Charles　Gordon；　Esq。；　of　Dulwich　Hill。　　〃The　velocity

and　steadiness　of　the　motion；〃　said　Dr。　Birkbeck　in　his　letter；

〃so　far　exceeded　that　of　the　same　model　when　impelled　by

paddle…wheels　driven　by　the　same　spring；　that　I　could　not　doubt

its　superiority；　and　the　stillness　of　the　water　was　such　as　to

give　the　vessel　the　appearance　of　being　moved　by　some　magical

power。〃



Then　comes　another　claimantMr。　Robert　Wilson；　then　of　Dunbar

（not　far　from　Coldingham）；　but　afterwards　of　the　Bridgewater

Foundry；　Patricroft。　　In　his　pamphlet；　published　a　few　years　ago；

he　states　that　he　had　long　considered　the　subject；　and　in　1827　he

made　a　small　model；　fitted　with　〃revolving　skulls；〃　which　he

tried　on　a　sheet　of　water　in　the　presence　of　the　Hon。　Capt。

Anthony　Maitland；　son　of　the　Earl　of　Lauderdale。　　The　experiment

was　successfulso　successful；　that　when　the　〃stern　paddles〃　were

in　1828　used　at　Leith　in　a　boat　twenty…five　feet　long；　with　two

men　to　work　the　machinery；　the　boat　was　propelled　at　an　average

speed　of　about　ten　miles　an　hour；　and　the　Society　of　Arts

afterwards；　in　October；　1882；　awarded　Mr。　Wilson　their　silver

medal　for　the　〃description；　drawing；　and　models　of　stern　paddles

for　propelling　steamboats；　invented　by　him。〃　　The　subject　was；　in

1833；　brought　by　Sir　John　Sinclair　under　the　consideration　of　the

Board　of　Admiralty；　but　the　report　of　the　officials　（Oliver　Lang；

Abethell；　Lloyd；　and　Kingston）　was　to　the　effect　that　〃the　plan

proposed　（independent　of　practical　difficulties）　is

objectionable；　as　it　involves　a　greater　loss　of　power　than　the

common　mode　of　applying　the　wheels　to　the　side。〃　　And　here　ended

the　experiment；　so　far　as　Mr。　Wilson's　〃stern　paddles〃　were

concerned。



It　will　be　observed；　from　what　has　been　said；　that　the　idea　of　a

screw　propeller　is　a　very　old　one。　　Watt；　Bramah；　Trevethick；　and

many　more；　had　given　descriptions　of　the　screw。　　Trevethick

schemed　a　number　of　its　forms　and　applications；　which　have　been

the　subject　of　many　subsequent　patents。　　It　has　been　so　with　many

inventions。　　It　is　not　the　man　who　gives　the　first　idea　of　a

machine　who　is　entitled　to　the　merit　of　its　introduction；　or　the

man　who　repeats　the　idea；　and　re…repeats　it；　but　the　man　who　is

so　deeply　impressed　with　the　importance　of　the　discovery；　that　he

insists　upon　its　adoption；　will　take　no　denial；　and　at　the　risk

of　fame　and　fortune；　pushes　through　all　opposition；　and　is

determined　that　what　he　thinks　he　has　discovered　shall　not　perish

for　want　of　a　fair　trial。　　And　that　this　was　the　case　with　the

practical　introducer　of　the　screw　propeller　will　be　obvious　from

the　following　statement。



Francis　Pettit　Smith　was　born　at　Hythe；　in　the　county　of　Kent；　in

1808。　　His　father　was　postmaster　of　the　town；　and　a　person　of

much　zeal　and　integrity。　　The　boy　was　sent　to　school　at　Ashford；

and　there　received　a　fair　amount　of　education；　under　the　Rev。

Alexander　Power。　　Young　Smith　displayed　no　special　characteristic

except　a　passion　for　constructing　models　of　boats。　　When　he

reached　manhood；　he　adopted　the　business　of　a　grazing　farmer　on

Romney　Marsh。　　He　afterwards　removed　to　Hendon；　north　of　London；

where　he　had　plenty　of　water　on　which　to　try　his　model　boats。　

The　reservoir　of　the　Old　Welsh　Harp　was　close　at　handa　place

famous　for　its　water…birds　and　wild　fowl。



Smith　made　many　models　of　boats；　his　experiments　extending　over

many　years。　　In　1834；　he　constructed　a　boat　propelled　by　a　wooden

screw　driven　by　a　spring；　the　performance　of　which　was　thought

extraordinary。　　Where　he　had　got　his　original　idea　is　not　known。　

It　was　floating　about　in　many　minds；　and　was　no　special　secret。　

Smith；　however；　arrived　at　the　conclusion　that　his　method　of

propelling　steam　vessels　by　means　of　a　screw　was　much　superior　to

paddlesat　that　time　exclusively　employed。　　In　the　following

year；　1835；　he　constructed　a　superior　model；　with　which　he

performed　a　number　of　experiments　at　Hendon。　　In　May　1836；　he

took　out　a　patent　for　propelling　vessels　by　means　of　a　screw

revolving　beneath　the　water　at　the　stern。　　He　then　openly

exhibited　his　invention　at　the　Adelaide　Gallery　in　London。　　Sir

John　Barrow；　Secretary　to　the　Admiralty；　inspected　the　model；　and

was　much　impressed　by　its　action。　　During　the　time　it　was

publicly　exhibited；　an　offer　was　made　to　purchase　the　invention

for　the　Pacha　of　Egypt；　but　the　offer　was　declined。



At　this　stage　of　his　operations；　Smith　was　joined　by　Mr。　Wright；

banker；　and　Mr。　C。　A。　Caldwell；　who　had　the　penetration　to

perceive　that　the　invention　was　one　of　much　promise；　and　were

desirous　of　helping　its　introduction　to　general　use。　　They

furnished　Smith　with　the　means　of　constructing　a　more　complete

model。　　In　the　autumn　of　1836；　a　small　steam　vessel　of　10　tons

burthen　and　six　horse…power　was　built；　further　to　test　the

advantages　of　the　invention。　　This　boat　was　fitted　with　a　wooden

screw　of　two　whole　turns。　　On　the　1st　of　November　the　vessel　was

exhibited　to　the　public　on　the　Paddington　Canal；　as　well　as　on

the　Thames；　where　she　continued　to　ply　until　the　month　of

September　1837。



During　the　trips　upon　the　Thames；　a　happy　accident　occurred；

which　first　suggested　the　advantage　of　reducing　the　length　of　the

screw。　　The　propeller　having　struck　upon　some　obstacle　in　the

water；　about　one…half　of　the　length　of　the　screw　was　broken　off；

and　it　was　found　that；　the　vessel　immediately　shot　ahead　and

attained　a　much　greater　speed　than　before。　　In　consequence　of

this　discovery；　a　new　screw　of　a　single　turn　was　fitted　to　her；

after　which　she　was　found　to　work　much　better。



Having　satisfied　himself　as　to　the　eligibility　of　the　propeller

in　smooth　water；　Mr。　Smith　then　resolved　to　take　his　little

vessel　to　the　open　sea；　and　breast　the　winds　and　the　waves。　

Accordingly；　one　Saturday　in　the　month　of　September　1837；　he

proceeded　in　his　miniature　boat；　down　the　river；　from　Blackwall

to　Gravesend。　　There　he　took　a　pilot　on　board；　and　went　on　to

Ramsgate。　　He　passed　through　the　Downs；　and　reached　Dover　in

safety。　　A　trial　of　the　vessel's　performance　was　made　there　in

the　presence　of　Mr。　Wright；　the　banker；　and　Mr。　Peake；　the　civil

engineer。　　From　Dover　the　vessel　went　on　to　Folkestone　and　Hythe；

encountering　severe　weather。　　Nevertheless；　the　boat　behaved

admirably；　and　attained　a　speed　of　over　seven　miles　an　hour。



Though　the　weather　had　become　stormy　and　boisterous；　the　little

vessel　nevertheless　set　out　on　her　return　voyage　to　London。　

Crowds　of　people　assembled　to　witness　her　departure；　and　many

nautical　men　watched　her　progress　with　solicitude　as　she　steamed

through　the　waves　under　the　steep　cliffs　of　the　South　Foreland。　

The　courage　of　the　undertaking；　and　the　unexpected　good

performance　of　the　little　vessel；　rendered　her　an　object　of　great

interest　and　excitement　as　she　〃screwed〃　her　way　along　the　coast。



The　tiny　vessel　reach