the dominion of the air-第3部分

快捷操作: 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! 如果本书没有阅读完，想下次继续接着阅读，可使用上方 "收藏到我的浏览器" 功能 和 "加入书签" 功能！


was　experimenting　on　kindred　lines；　while　in　our　own　land　the　rival　geniuses　of　Priestley　and　Cavendish　were　clearing　the　way　to　make　with　respect　to　the　atmosphere　the　most　important　discovery　yet　dreamed　of。　　In　recording　this　dawn　of　a　new　era；　however；　we　should　certainly　not　forget　how；　across　the　Atlantic；　had　arisen　a　Rumford　and　a　Franklin；　whose　labours　were　destined　to　throw　an　all…important　sidelight　on　the　pages　of　progress　which　we　have　now　to　chronicle。



CHAPTER　II。　THE　INVENTION　OF　THE　BALLOON。


It　was　a　November　night　of　the　year　1782；　in　the　little　town　of　Annonay；　near　Lyons。　　Two　young　men；　Stephen　and　Joseph　Montgolfier；　the　representatives　of　a　firm　of　paper　makers；　were　sitting　together　over　their　parlour　fire。　　While　watching　the　smoke　curling　up　the　chimney　one　propounded　an　idea　by　way　of　a　sudden　inspiration：　　〃Why　shouldn't　smoke　be　made　to　raise　bodies　into　the　air？〃

The　world　was　waiting　for　this　utterance；　which；　it　would　seem；　was　on　the　tip　of　the　tongue　with　many　others。　Cavendish　had　already　discovered　what　he　designated　〃inflammable　air；〃　though　no　one　had　as　yet　given　it　its　later　title　of　hydrogen　gas。　　Moreover；　in　treating　of　this　gasDr。　Black　of　Edinburgh；　as　much　as　fifteen　years　before　the　date　we　have　now　arrived　at；　had　suggested　that　it　should　be　made　capable　of　raising　a　thin　bladder　in　the　air。　　With　a　shade　more　of　good　fortune；　or　maybe　with　a　modicum　more　of　leisure；　the　learned　Doctor　would　have　won　the　invention　of　the　balloon　for　his　own　country。　　Cavallo　came　almost　nearer；　and　actually　putting　the　same　idea　into　practice；　had　succeeded　in　the　spring　of　1782　in　making　soap　bubbles　blown　with　hydrogen　gas　float　upwards。　　But　he　had　accomplished　no　more　when；　as　related；　in　the　autumn　of　the　same　year　the　brothers　Montgolfier　conceived　the　notion　of　making　bodies　〃levitate〃　by　the　simpler　expedient　of　filling　them　with　smoke。

This　was　the　crude　idea；　the　application　of　which　in　their　hands　was　soon　marked　with　notable　success。　　Their　own　trade　supplied　ready　and　suitable　materials　for　a　first　experiment；　and；　making　an　oblong　bag　of　thin　paper　a　few　feet　in　length；　they　proceeded　to　introduce　a　cloud　of　smoke　into　it　by　holding　crumpled　paper　kindled　in　a　chafing　dish　beneath　the　open　mouth。　　What　a　subject　is　there　here　for　an　imaginative　painter！　　As　the　smoky　cloud　formed　within；　the　bag　distended　itself；　became　buoyant；　and　presently　floated　to　the　ceiling。　　The　simple　trial　proved　a　complete　success；　due；　as　it　appeared　to　them；　to　the　ascensive　power　of　a　cloud　of　smoke。

An　interesting　and　more　detailed　version　of　the　story　is　extant。　　While　the　experiment　was　in　progress　a　neighbour；　the　widow　of　a　tradesman　who　had　been　connected　in　business　with　the　firm；　seeing　smoke　escaping　into　the　room；　entered　and　stood　watching　the　proceedings；　which　were　not　unattended　with　difficulties。　　The　bag；　half　inflated；　was　not　easy　to　hold　in　position　over　the　chafing　dish；　and　rapidly　cooled　and　collapsed　on　being　removed　from　it。　　The　widow　noting　this；　as　also　the　perplexity　of　the　young　men；　suggested　that　they　should　try　the　result　of　tying　the　dish　on　at　the　bottom　of　the　bag。　　This　was　the　one　thing　wanted　to　secure　success；　and　that　good　lady；　whose　very　name　is　unhappily　lost；　deserves　an　honoured　place　in　history。　　It　was　unquestionably　the　adoption　of　her　idea　which　launched　the　first　balloon　into　space。

The　same　experiment　repeated　in　the　open　air　proving　a　yet　more　pronounced　success；　more　elaborate　trials　were　quickly　developed；　and　the　infant　balloon　grew　fast。　　One　worthy　of　the　name；　spherical　in　shape　and　of　some　600　cubic　feet　capacity；　was　now　made　and　treated　as　before；　with　the　result　that　ere　it　was　fully　inflated　it　broke　the　strings　that　held　it　and　sailed　away　hundreds　of　feet　into　the　air。　　The　infant　was　fast　becoming　a　prodigy。　　Encouraged　by　their　fresh　success；　the　inventors　at　once　set　about　preparations　for　the　construction　of　a　much　larger　balloon　some　thirty…five　feet　diameter　（that　is；　of　about　23；000　cubic　feet　capacity）；　to　be　made　of　linen　lined　with　paper　and　this　machine；　launched　on　a　favourable　day　in　the　following　spring；　rose　with　great　swiftness　to　fully　a　thousand　feet；　and　travelled　nearly　a　mile　from　its　starting　ground。

Enough；　the　time　was　already　ripe　for　a　public　demonstration　of　the　new　invention；　and　accordingly　the　5th　of　the　following　June　witnessed　the　ascent　of　the　same　balloon　with　due　ceremony　and　advertisement。　　Special　pains　were　taken　with　the　inflation；　which　was　conducted　over　a　pit　above　which　the　balloon　envelope　was　slung；　and　in　accordance　with　the　view　that　smoke　was　the　chief　lifting　power；　the　fuel　was　composed　of　straw　largely　mixed　with　wool。　　It　is　recorded　that　the　management　of　the　furnace　needed　the　attention　of　two　men　only；　while　eight　men　could　hardly　hold　the　impatient　balloon　in　restraint。　　The　inflation；　in　spite　of　the　fact　that　the　fuel　chosen　was　scarcely　the　best　for　the　purpose；　was　conducted　remarkable　expedition；　and　on　being　released；　the　　craft　travelled　one　and　a　half　miles　into　the　air；　attaining　a　height　estimated　at　over　6；000　feet。

From　this　time　the　tide　of　events　in　the　aeronautical　world　rolls　on　in　full　flood；　almost　every　half…year　marking　a　fresh　epoch；　until　a　new　departure　in　the　infant　art　of　ballooning　was　already　on　the　point　of　being　reached。　　It　had　been　erroneously　supposed　that　the　ascent　of　the　Montgolfier　balloon　had　been　due；　not　to　the　rarefaction　of　the　air　within　itwhich　was　its　true　causebut　to　the　evolution　of　some　light　gas　disengaged　by　the　nature　of　the　fuel　used。　　It　followed；　therefore；　almost　as　a　matter　of　course；　that　chemists；　who；　as　stated　in　the　last　chapter；　were　already　acquainted　with　so…called　〃inflammable　air；〃　or　hydrogen　gas；　grasped　the　fact　that　this　gas　would　serve　better　than　any　other　for　the　purposes　of　a　balloon。　　And　no　sooner　had　the　news　of　the　Montgolfiers'　success　reached　Paris　than　a　subscription　was　raised；　and　M。　Charles；　Professor　of　Experimental　Philosophy；　was　appointed；　with　the　assistance　of　M。　Roberts；　to　superintend　the　construction　of　a　suitable　balloon　and　its　inflation　by　the　proposed　new　method。

The　task　was　one　of　considerable　difficulty；　owing　partly　to　the　necessity　of　procuring　some　material　which　would　prevent　the　escape　of　the　lightest　and　most　subtle　gas　known；　and　no　less　by　reason　of　the　difficulty　of　preparing　under　pressure　a　sufficient　quantity　of　gas　itself。　　The　experiment；　sound　enough　in　theory；　was　eventually　carried　through　after　several　instructive　failures。　　A　suitable　material　was　found　in　〃lustring；〃　a　glossy　silk　cloth　varnished　with　a　solution　of　caoutchouc；　and　this　being　formed　into　a　balloon　only　thirteen　feet　in　diameter　and　fitted　without　other　aperture　than　a　stopcock；　was　after　several　attempts　filled　with　hydrogen　gas　prepared　in　the　usual　way　by　the　action　of　dilute　sulphuric　acid　on　scrap　iron。

The　preparations　completed；　one　last　and　all…important　mistake　was　made　by　closing　the　stop…cock　before　the　balloon　was　dismissed；　the　disastrous　and　unavoidable　result　of　this　being　at　the　time　overlooked。

On　August　25；　1783；　the　balloon　was　liberated　on　the　Champ　de　Mars　before　an　enormous　concourse；　and　in　less　than　two　minutes　had　reached　an　elevation　of　half　a　mile；　when　it　was　temporarily　lost　in　cloud；　through　which；　however；　it　penetrated；　climbing　into　yet　higher　cloud；　when；　disappearing　from　sight；　it　presently　burst　and　descended　to　earth　after　remaining　in　the　air　some　three…quarters　of　an　hour。

The　bursting　of　this　little　craft　taught　the　future　balloonist　his　first　great　lesson；　namely；　that　on　leaving　earth　he　must　open　the　neck　of　his　balloon；　and　the　reason　of　this　is　obvious。　　While　yet　on　earth　the　imprisoned　gas　of　a　properly　filled　balloon　distends　the　silk　by　virtue　of　its　expansive　force；　and　in　spite　of　the　enormous　outside　pressure　which　the　weight　of　air　exerts　upon　it。　　Then；　as　the　balloon　rises　high　in　the　air　and　the　outside　pressure　grows　less；　the　struggling　gas　within；　if　allowed　no　vent；　stretches　the　balloon　more　and　more　until　the　slender　fabric　bursts　under　the　strain。

At　the　risk　of　being　tedious；　we　have　dwelt　at　some　length　on　the　initial　experiments　which　in　less　than　a　single　year　had　led　to　the　discovery　and　development　of　two　distinct　methodsstill　employed　and　in　competition　with　each　otherof　dismissing　balloons　into　the　heavens。　　We　are　now　prepared　to　enter　fully　into　the　romantic　history　of　our　subject　which　from　this　point　rapidly　unfolds　itself。

Some　eleven　months　only　after　the　two　Montgolfiers　were　discovered　toying　with　their　inflated　paper　bag；　the　younger　of　the　two　brothers　was　engaged　to　make　an　exhibition　of　his　new　art　before　the　King　at　Versailles；　and　this　was　destined　to　be　the　first　occasion　when　a　balloon　was　to　carry　a　living　freight　into　the　sky。　　The　stately　structure；　which　was　gorgeously　decorated；　towered　some　seventy　feet　into　the　air；　and　was　furnished　with　a　wicker　car　in　which　the　passengers　were　duly　installed。　　These　were　three　in　number；　a　sheep；　a　cock；　and　a　duck；　and　amid　the　acclamations　of　the　multitude；　rose　a　few　hundred　feet　and　descended　half　a　mile　away。　　The　cock　was　found　to　have　sustained　an　unexplained　mishap：　　its　leg　was　broken；　but　the　sheep　was　feeding　complacently；　and　the　duck　was　quacking　with　much　apparent　satisfaction。

Now；　who　among　mortals　will　come　forward　and　win　the　honour　of　being　the　first　to　sail　the　skies？　　M。　Pilitre　de　Rozier　at　once　volunteered；　and　by　the　month　of　November　a　new　air　ship　was　built；　74　feet　high；　48　feet　in　largest　diameter；　and　15　feet　across　the　neck；　outside　which　a　wicker　gallery　was　constructed；　while　an　iron　brazier　was　slung　below　all。　　But　to　trim　the　boat　properly　two　passengers　were　needed；　and　de　Rozier　found　a　ready　colleague　in　the　Marquis　d'Arlandes。　　By　way　of　precaution；　de　Rozier　made　a　few　preliminary　ascents　with　the　balloon　held　captive；　and　then　the　two　intrepid　Frenchmen　took　their　stand　on　opposite　sides　of　the　gallery；　each　furnished　with　bundles　of　fuel　to　feed　the　furnace；　each　also　carrying　a　large　wet　sponge　with　which　to　extinguish　the　flames　whenever　the　machine　might　catch　fire。　　On　casting　off　the　balloon