the age of invention-第31节

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ned　unto　themselves　wings；　but；　though　some　of　them　might　glide　earthward；　none　could　rise　upon　the　wind。

While　the　principle　by　which　the　balloon；　father　of　the　dirigible；　soars　and　floats　could　be　deduced　by　men　of　natural　powers　of　observation　and　little　science　from　the　action　of　clouds　and　smoke；　the　airplane；　the　Winged　Victory　of　our　day；　waited　upon　two　thingsthe　scientific　analysis　of　the　anatomy　of　bird　wings　and　the　internal　combustion　engine。

These　two　things　necessary　to　convert　man　into　a　rival　of　the　albatross　did　not　come　at　once　and　together。　Not　the　dream　of　flying　but　the　need　for　quantity　and　speed　in　production　to　take　care　of　the　wants　of　a　modern　civilization　compelled　the　invention　of　the　internal　combustion　engine。　Before　it　appeared　in　the　realm　of　mechanics；　experimenters　were　applying　in　the　construction　of　flying　models　the　knowledge　supplied　by　Cayley　in　1796；　who　made　an　instrument　of　whalebone；　corks；　and　feathers；　which　by　the　action　of　two　screws　of　quill　feathers；　rotating　in　opposite　directions；　would　rise　to　the　ceiling；　and　the　full　revelation　of　the　structure　and　action　of　bird　wings　set　forth　by　Pettigrew　in　1867。

〃The　wing；　both　when　at　rest　and　when　in　motion；〃　Pettigrew　declared；　〃may　not　inaptly　be　compared　to　the　blade　of　an　ordinary　screw　propeller　as　employed　in　navigation。　Thus　the　general　outline　of　the　wing　corresponds　closely　with　the　outline　of　the　propeller；　and　the　track　described　by　the　wing　in　space　IS　TWISTED　UPON　ITSELF　propeller　fashion。〃　Numerous　attempts　to　apply　the　newly　discovered　principles　to　artificial　birds　failed；　yet　came　so　close　to　success　that　they　fed　instead　of　killing　the　hope　that　a　solution　of　the　problem　would　one　day　ere　long　be　reached。


〃Nature　has　solved　it；　and　why　not　man？〃

From　his　boyhood　days　Samuel　Pierpont　Langley；　so　he　tells　us；　had　asked　himself　that　question；　which　he　was　later　to　answer。　Langley；　born　in　Roxbury；　Massachusetts；　in　1834；　was　another　link　in　the　chain　of　distinguished　inventors　who　first　saw　the　light　of　day　in　Puritan　New　England。　And；　like　many　of　those　other　inventors；　he　numbered　among　his　ancestors　for　generations　two　types　of　menon　the　one　hand；　a　line　of　skilled　artisans　and　mechanics；　on　the　other；　the　most　intellectual　men　of　their　time　such　as　clergymen　and　schoolmasters；　one　of　them　being　Increase　Mather。　We　see　in　Langley；　as　in　some　of　his　brother　New　England　inventors；　the　later　flowering　of　the　Puritan　ideal　stripped　of　its　husk　of　superstition　and　harshnessa　high　sense　of　duty　and　of　integrity；　an　intense　conviction　that　the　reason　for　a　man's　life　here　is　that　he　may　give　service；　a　reserved　deportment　which　did　not　mask　from　discerning　eyes　the　man's　gentle　qualities　of　heart　and　his　keen　love　of　beauty　in　art　and　Nature。

Langley　first　chose　as　his　profession　civil　engineering　and　architecture　and　the　years　between　1857　and　1864　were　chiefly　spent　in　prosecuting　these　callings　in　St。　Louis　and　Chicago。　Then　he　abandoned　them；　for　the　bent　of　his　mind　was　definitely　towards　scientific　inquiry。　In　1867　he　was　appointed　director　of　the　Allegheny　Observatory　at　Pittsburgh。　Here　he　remained　until　1887；　when；　having　made　for　himself　a　world…wide　reputation　as　an　astronomer；　he　became　Secretary　of　the　Smithsonian　Institution　at　Washington。

It　was　about　this　time　that　he　began　his　experiments　in　〃aerodynamics。〃　But　the　problem　of　flight　had　long　been　a　subject　of　interested　speculation　with　him。　Ten　years　later　he　wrote：

〃Nature　has　made　her　flying…machine　in　the　bird；　which　is　nearly　a　thousand　times　as　heavy　as　the　air　its　bulk　displaces；　and　only　those　who　have　tried　to　rival　it　know　how　inimitable　her　work　is；　for　the　〃way　of　a　bird　in　the　air〃　remains　as　wonderful　to　us　as　it　was　to　Solomon；　and　the　sight　of　the　bird　has　constantly　held　this　wonder　before　men's　minds；　and　kept　the　flame　of　hope　from　utter　extinction；　in　spite　of　long　disappointment。　I　well　remember　how；　as　a　child；　when　lying　in　a　New　England　pasture；　h　watched　a　hawk　soaring　far　up　in　the　blue；　and　sailing　for　a　long　time　without　any　motion　of　its　wings；　as　though　it　needed　no　work　to　sustain　it；　but　was　kept　up　there　by　some　miracle。　But；　however　sustained；　I　saw　it　sweep　in　a　few　seconds　of　its　leisurely　flight；　over　a　distance　that　to　me　was　encumbered　with　every　sort　of　obstacle；　which　did　not　exist　for　it　。　。　。　。　How　wonderfully　easy；　too；　was　its　flight！　There　was　not　a　flutter　of　its　pinions　as　it　swept　over　the　field；　in　a　motion　which　seemed　as　effortless　as　that　of　its　shadow。　After　many　years　and　in　mature　life；　I　was　brought　to　think　of　these　things　again；　and　to。　ask　myself　whether　the　problem　of　artificial　flight　was　as　hopeless　and　as　absurd　as　it　was　then　thought　to　be〃。。。　In　three　or　four　years　Langley　made　nearly　forty　models。　〃The　primary　difficulty　lay　in　making　the　model　light　enough　and　sufficiently　strong　to　support　its　power；〃　he　says。　〃This　difficulty　continued　to　be　fundamental　through　every　later　form；　but；　beside　this；　the　adjustment　of　the　center　of　gravity　to　the　center　of　pressure　of　the　wings；　the　disposition　of　the　wings　themselves；　the　size　of　the　propellers；　the　inclination　and　number　of　the　blades；　and　a　great　number　of　other　details；　presented　themselves　for　examination。〃

By　1891　Langley　had　a　model　light　enough　to　fly；　but　proper　balancing　had　not　been　attained。　He　set　himself　anew　to　find　the　practical　conditions　of　equilibrium　and　of　horizontal　flight。　His　experiments　convinced　him　that　〃mechanical　sustenation　of　heavy　bodies　in　the　air；　combined　with　very　great　speeds；　is　not　only　possible；　but　within　the　reach　of　mechanical　means　we　actually　possess。〃

After　many　experiments　with　new　models　Langley　at　length　fashioned　a　steam…driven　machine　which　would　fly　horizontally。　It　weighed　about　thirty　pounds；　it　was　some　sixteen　feet　in　length；　with　two　sets　of　wings；　the　pair　in　front　measuring　forty　feet　from　tip　to　tip。　On　May　6；　1896；　this　model　was　launched　over　the　Potomac　River。　It　flew　half　a　mile　in　a　minute　and　a　half。　When　its　fuel　and　water　gave　out；　it　descended　gently　to　the　river's　surface。　In　November　Langley　launched　another　model　which　flew　for　three…quarters　of　a　mile　at　a　speed　of　thirty　miles　an　hour。　These　tests　demonstrated　the　practicability　of　artificial　flight。

The　Spanish…American　War　found　the　military　observation　balloon　doing　the　limited　work　which　it　had　done　ever　since　the　days　of　Franklin。　President　McKinley　was　keenly　interested　in　Langley's　design　to　build　a　power…driven　flying　machine　which　would　have　innumerable　advantages　over　the　balloon。　The　Government　provided　the　funds　and　Langley　took　up　the　problem　of　a　flying　machine　large　enough　to　carry　a　man。　His　initial　difficulty　was　the　engine。　It　was　plain　at　once　that　new　principles　of　engine　construction　must　be　adopted　before　a　motor　could　be　designed　of　high　power　yet　light　enough　to　be　borne　in　the　slender　body　of　an　airplane。　The　internal　combustion　engine　had　now　come　into　use。　Langley　went　to　Europe　in　1900；　seeking　his　motor；　only　to　be　told　that　what　he　sought　was　impossible。

His　assistant；　Charles　M。　Manly；　meanwhile　found　a　builder　of　engines　in　America　who　was　willing　to　make　the　attempt。　But；　after　two　years　of　waiting　for　it；　the　engine　proved　a　failure。　Manly　then　had　the　several　parts　of　it；　which　he　deemed　hopeful；　transported　to　Washington；　and　there　at　the　Smithsonian　Institution　he　labored　and　experimented　until　he　evolved　a　light　and　powerful　gasoline　motor。　In　October；　1903；　the　test　was　made；　with　Manly　aboard　of　the　machine。　The　failure　which　resulted　was　due　solely　to　the　clumsy　launching　apparatus。　The　airplane　was　damaged　as　it　rushed　forward　before　beginning　to　soar；　and；　as　it　rose；　it　turned　over　and　plunged　into　the　river。　The　loyal　and　enthusiastic　Manly；　who　was　fortunately　a　good　diver　and　swimmer；　hastily　dried　himself　and　gave　out　a　reassuring　statement　to　the　representatives　of　the　press　and　to　the　officers　of　the　Board　of　Ordnance　gathered　to　witness　the　flight。

A　second　failure　in　December　convinced　spectators　that　man　was　never　intended　to　fly。　The　newspapers　let　loose　such　a　storm　of　ridicule　upon　Langley　and　his　machine；　with　charges　as　to　the　waste　of　public　funds；　that　the　Government　refused　to　assist　him　further。　Langley；　at　that　time　sixty…nine　years　of　age；　took　this　defeat　so　keenly　to　heart　that　it　hastened　his　death；　which　occurred　three　years　later。　〃Failure　in　the　aerodrome　itself；〃　he　wrote；　〃or　its　engines　there　has　been　none；　and　it　is　believed　that　it　is　at　the　moment　of　success；　and　when　the　engineering　problems　have　been　solved；　that　a　lack　of　means　has　prevented　a　continuance　of　the　work。〃


It　was　truly　〃at　the　moment　of　success〃　that　Langley's　work　was　stopped。　On　December　17；　1903；　the　Wright　brothers　made　the　first　successful　experiment　in　which　a　machine　carrying　a　man　rose　by　its　own　power；　flew　naturally　and　at　even　speed；　and　descended　without　damage。　These　brothers；　Wilbur　and　Orville；　who　at　last　opened　the　long　besieged　lanes　of　the　air；　were　born　in　Dayton；　Ohio。　Their　father；　a　clergyman　and　later　a　bishop；　spent　his　leisure　in　scientific　reading　and　in　the　invention　of　a　typewriter　which；　however；　he　never　perfected。