the dominion of the air-第17节
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He could then do no more； and presently subsiding to earth again； he acquired the welcome knowledge that even in such precarious circumstances a balloon may make a long fall with safety to its freight。
Mr。 Wise's zeal and indomitable spirit of enterprise led to speedy developments of the art which he had espoused； the road to success being frequently pointed out by failure or mishap。 He quickly discarded the linen balloon for one of silk on which he tried a new varnish composed of linseed oil and india…rubber； and； dressing several gores with this； he rolled them up and left them through a night in a drying loft； with the result that the next day they were disintegrated and on the point of bursting into flame by spontaneous combustion。 Fresh silk and other varnish were then tried； but with indifferent success。 Next he endeavoured to dispense with sewing； and united the gores of yet another balloon by the mere adhesiveness of the varnish and application of a hot iron。 This led to a gaping seam developing at the moment of an ascent； and then there followed a hasty and hazardous descent on a house…top and an exciting rescue by a gentleman who appeared opportunely at a third storey window。 Further； another balloon had been destroyed； and Wise badly burned； at a descent； owing to a naked light having been brought near the escaping gas。 It is then without wonder that we find him after this temporarily bankrupt； and resorting to his skill in instrument…making to recover his fortunes。 Only； however； for a few months； after which he is before the public once more as a professional aeronaut。 He now adopts coal gas for inflation； and incidents of an impressive nature crowd into his career； forcing important facts upon him。 The special characteristics of his own country present peculiar difficulties； broad rivers and vast forests become serious obstacles。 He is caught in the embrace of a whirlwind； he narrowly escapes falling into a forest fire； he is precipitated； but harmlessly； into a pine wood。 Among other experiments； he makes a small copy of Mr。 Cocking's parachute； and drops it to earth with a cat as passenger； proving thereby that that unfortunate gentleman's principle was really less in fault than the actual slenderness of the material used in his machine。
We now approach one of Wise's boldest； and at the same time most valuable； experiments。 It was the summer of 1839； and once again the old trouble of spontaneous combustion had destroyed a silk balloon which was to have ascended at Easton； Pa。 Undeterred； however； Wise resolutely advertised a fresh attempt； and； with only a clear month before the engagement； determined on hastily rigging up a cambric muslin balloon； soaking it in linseed oil and essaying the best exhibition that this improvised experiment could afford。 It was intended to become a memorable one； inasmuch as； should he meet with no hindrance； his determination was nothing less than that of bursting this balloon at a great height； having firmly convinced himself that the machine in these circumstances would form itself into a natural parachute； and bring him to earth with every chance in favour of safety。 In his own words； 〃Scientific calculations were on his side with a certainty as great and principles as comprehensive as that a pocket…handkerchief will not fall as rapidly to the ground when thrown out of a third storey window as will a brick。〃
His balloon was specially contrived for the experiment in hand； having cords sewn to the upper parts of its seams； and then led down through the neck； where they were secured within reach； their office being that of rending the whole head of the balloon should this be desired。 On this occasion a cat and a dog were taken up； one of these being let fall from a height of 2；000 feet in a Cocking's parachute； and landing in safety； the other being similarly dismissed at an altitude of 4；000 feet in an oiled silk balloon made in the form of a collapsed balloon； which； after falling a little distance； expanded sufficiently to allow of its descending with a safe though somewhat vibratory motion。 Its behaviour； at any rate； fully determined Wise on carrying out his own experiment。
Being constructed entirely for the main object in view； the balloon had no true opening in the neck beyond an orifice of about an inch； and by the time a height of 13；000 feet had been reached the gas was streaming violently through this small hole； the entire globe being expanded nearly to bursting point； and the cords designed for rending the balloon very tense。 At this critical period Wise owns to having experienced considerable nervous excitement； and observing far down a thunderstorm in progress he began to waver in his mind； and inclined towards relieving the balloon of its strain； and so abandoning his experiment； at least for the present。 He remembers pulling out his watch to make a note of the hour； and； while thus occupied； the straining cords； growing tenser every moment； suddenly took charge of the experiment and burst the balloon of their own accord。 The gas now rushed from the huge rent above tumultuously and in some ten seconds had entirely escaped； causing the balloon to descend rapidly； until the lower part of the muslin； doubling in upwards； formed a species of parachute after the manner intended。 The balloon now came down with zig…zag descent； and finally the car； striking the earth obliquely； tossed its occupant out into a field unharmed。 Shortly after this Wise experimented with further success with an exploded balloon。
It is not a little remarkable that this pioneer of aeronautics in Americana contemporary of Charles Green in England； but working and investigating single…handed on perfectly independent linesshould have arrived at the same conclusions as did Green himself as to the possibility； which； in his opinion； amounted to a certainty； of being able to cross the Atlantic by balloon if only adequate funds were forth…coming。 So intent was he on his bold scheme that； in the summer of 1843； he handed to the Lancaster Intelligencer a proclamation； which he desired might be conveyed to all publishers of newspapers on the globe。 It contained； among other clauses； the following：
〃Having from a long experience in aeronautics been convinced that a constant and regular current of air is blowing at all times from west to east； with a velocity of from twenty to forty and even sixty miles per hour； according to its height from the earth； and having discovered a composition which renders silk or muslin impervious to hydrogen gas； so that a balloon may be kept afloat for many weeks； I feel confident with these advantages that a trip across the Atlantic will not be attended with as much real danger as by the common mode of transition。 The balloon is to be 100 feet in diameter； giving it a net ascending power of 25；000 lbs。〃 It was further stated that the crew would consist of three persons； including a sea navigator； and a scientific landsman。 The specifications for the transatlantic vessel were also to include a seaworthy boat in place of the ordinary car。 The sum requisite for this enterprise was； at the time； not realised； but it should be mentioned that several years later a sufficient sum of money was actually subscribed。 In the summer of 1873 the proprietors of the New York Daily Graphic provided for the construction of a balloon of no less than 400；000 cubic feet capacity； and calculated to lift 14；000 lbs。 It was； however； made of bad material； and； becoming torn in inflation； Wise condemned and declined to use it。 A few months later； when it had been repaired； one Donaldson and two other adventurers； attempting a voyage with this ill…formed monster； ascended from New York； and were fortunate in coming down safely； though not without peril； somewhere in Connecticut。
Failing in his grand endeavour； Wise continued to follow the career of a professional aeronaut for some years longer； of which he has left a full record； terminating with the spring of 1848。 His ascents were always marked by carefulness of detail； and a coolness and courage in trying circumstances that secured him uniform success and universal regard。 He was； moreover； always a close and intelligent observer； and many of his memoranda are of scientific value。
His description of an encounter with a storm…cloud in the June of 1843 has an interest of its own； and may not be considered overdrawn。 It was an ascent from Carlisle； Pa。； to celebrate the anniversary of Bunker's Hill； and Wise was anxious to gratify the large concourse of people assembled； and thus was tempted； soon after leaving the ground； to dive up into a huge black cloud of peculiarly forbidding aspect。 This cloud appeared to remain stationary while he swept beneath it； and； having reached its central position； he observed that its under surface was concave towards the earth； and at that moment he became swept upwards in a vortex that set his balloon spinning and swinging violently； while he himself was afflicted with violent nausea and a feeling of suffocation。 The cold experienced now became intense； and the cordage became glazed with ice； yet this had no effect in checking the upward whirling of the balloon。 Sun
