the dominion of the air-第15部分
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a given object。 During this frightful operation the gas was rushing in torrents from the upper and lower valve； but more particularly from the latter； as the density of the atmosphere through which we were forcing our progress pressed so heavily on the valve at the top of the balloon as to admit of but a comparatively small escape by this aperture。 At this juncture； had it not been for the application to our mouths of two pipes leading into an air bag； with which we had furnished ourselves previous to starting； we must within a minute have been suffocated； and so； but by different means； have shared the melancholy fate of our friend。 This bag was formed of silk； sufficiently capacious to contain 100 gallons of atmospheric air。 Prior to our ascent； the bag was inflated with the assistance of a pair of bellows with fifty gallons of air； so allowing for any expansion which might be produced in the upper regions。 Into the end of this bag were introduced two flexible tubes； and the moment we felt ourselves to be going up in the manner just described； Mr。 Spencer； as well as myself； placed either of them in our mouths。 By this simple contrivance we preserved ourselves from instantaneous suffocation； a result which must have ensued from the apparently endless volume of gas with which the car was enveloped。 The gas； notwithstanding all our precautions； from the violence of its operation on the human frame； almost immediately deprived us of sight； and we were both； as far as our visionary powers were concerned； in a state of total darkness for four or five minutes。〃
Messrs。 Green and Spencer eventually reached earth in safety near Maidstone； knowing nothing of the fate of their late companion。 But of this we are sufficiently informed through a Mr。 R。 Underwood； who was on horseback near Blackheath and watching the aeronauts at the moment when the parachute was separated from the balloon。 He noticed that the former descended with the utmost rapidity； at the same time swaying fearfully from side to side； until the basket and its occupant； actually parting from the parachute； fell together to earth through several hundred feet and were dashed to pieces。
It would appear that the liberation of the parachute from below the balloon had been carried out without hitch； indeed； all so far had worked well； and the wind at the time was but a gentle breeze。 The misadventure； therefore； must be entirely attributed to the faulty manner in which the parachute was constructed。 There could； of course； be only one issue to the sheer drop from such a height； which became the unfortunate Mr。 Cocking's fate； but the very interesting question will have to be discussed as to the chances in favour of the aeronaut who； within his wicker car； while still duly attached to the balloon； may meet with a precipitate descent。
We may here fitly mention an early perilous experience of Mr。 Green； due simply to the malice of someone never discovered。 It appears that while Green's balloon； previous to an ascent； was on the ground； the cords attaching the car had been partly severed in such a way as to escape detection。 So that as soon as the balloon rose the car commenced breaking away； and its occupants； Mr。 Green and Mr。 Griffiths； had to clutch at the ring； to which with difficulty they continued to cling。 Meanwhile； the car remaining suspended by one cord only； the balloon was caused to hang awry； with the result that its upper netting began giving way； allowing the balloon proper gradually to escape through the bursting meshes； thus threatening the distracted voyagers with terrible disaster。 The disaster； in fact； actually came to pass ere the party completed their descent； 〃the balloon； rushing through the opening in the net…work with a tremendous explosion； and the two passengers clinging to the rest of the gear； falling through a height said to be near a hundred feet。 Both； though only with much time and difficulty； recovered from the shock。〃
In 1840； three years after the tragic adventure connected with Mr。 Cocking's parachute trial； we find Charles Green giving his views as to the practicability of carrying out a ballooning enterprise which should far excel all others that had hitherto been attempted。 This was nothing less than the crossing of the Atlantic from America to England。 There is no shadow of doubt that the adventurous aeronaut was wholly in earnest in the readiness he expressed to embark on the undertaking should adequate funds be forthcoming； and he discusses the possibilities with singular clearness and candour。 He maintains that the actual difficulties resolve themselves into two only： first； the maintenance of the balloon in the sky for the requisite period of time； and； secondly； the adequate control of its direction in space。 With respect to the first difficulty； he points out the fact to which we have already referred； namely； that it is impossible to avoid the fluctuations of level in a balloon's course； 〃by which it constantly becomes alternately subjected to escape of gas by expansion； and consequent loss of ballast； to furnish an equivalent diminution of weight。〃 Taking his own balloon of 80；000 cubic feet by way of example； he shows that this； fully inflated on the earth； would lose 8；000 cubic feet of gas by expansion in ascending only 3；000 feet。 Moreover； the approach of night or passage through cloud or falling rain would occasion chilling of the gas or accumulation of moisture on the silk； in either case necessitating the loss of ballast； the store of which is always the true measure of the balloon's life。
To combat the above difficulty Green sanguinely relies on his favourite device of a trail or guide rope； whose function； being that of relieving the balloon of a material weight as it approaches the earth； could； he supposed； be made to act yet more efficiently when over the sea in the following manner。 Its length； suspended from the ring； being not less than 2；000 feet； it should have attached at its lower end at certain intervals a number of small； stout waterproof canvas bags； the apertures of which should be contrived to admit water； but to oppose its return。 Between these bags were to be conical floats； to support any length of the rope that might descend on the sea。 Now； should the balloon commence descending； it would simply deposit a certain portion of rope on the water until it regained equilibrium at no great decrease of altitude； and would thus continue its course until alteration of conditions should cause it to recommence rising； when the weight of water now collected in the bags would play its part in preventing the balloon from soaring up into space。 With such a contrivance Green allowed himself to imagine that he could keep a properly made balloon at practically the same altitude for a period of three months if required。
The difficulty of maintaining a due course was next discussed； and somewhat speedily disposed of。 Here Green relied on the results of his own observation； gathered during 275 ascents； and stated his conviction that there prevails a uniformity of upper wind currents that would enable him to carry out his bold projects successfully。 His contention is best given in his own words：？
〃Under whatever circumstances；〃 he says； 〃I made my ascent； however contrary the direction of the winds below； I uniformly found that at a certain elevation； varying occasionally； but always within 10；000 feet of the earth； a current from the west or rather from the north of west； invariably travailed； nor do I recollect a single instance in which a different result ensued。〃 Green's complete scheme is now sufficiently evident。 He was to cross the Atlantic practically by the sole assistance of upper currents and his guide rope； but on this latter expedient； should adverse conditions prevail； he yet further relied； for he conceived that the rope could have attached to its floating end a water drag； which would hold the balloon in check until favouring gales returned。
Funds； apparently； were not forthcoming to allow of Mr。 Green's putting his bold method to the test； but we find him still adhering with so much zeal to his project that； five years later； he made； though again unsuccessfully； a second proposal to cross the Atlantic by balloon。 He still continued to make many and most enterprising ascents； and one of a specially sensational nature must be briefly mentioned before we pass on to regard the exploits of other aeronauts。
It was in 1841 on the occasion of a fete at Cremorne House； when Mr。 Green； using his famous Nassau balloon； ascended with a Mr。 Macdonnell。 The wind was blowing with such extreme violence that Rainham； in Essex； about twenty miles distant； was reached in little more than a quarter of an hour； and here； on nearing the earth； the grapnel； finding good hold； gave a wrench to the balloon that broke the ring and jerked the car completely upside down； the aeronauts only escaping precipitation by holding hard to the ropes。 A terrific steeplechase ensued； in which the travellers were dragged through stout fencing and other obstacles till the balloon； fairly emptied of gas； finally came to rest； but not until some severe injuries had been received。
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