the dominion of the air-第24章
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In after years Coxwell referred to his first sensations in characteristic language； contrasting them with the experiences of the mountaineer。 〃In Alpine travels；〃 he says； 〃the process is so slow； and contact with the crust of the earth so palpable； that the traveller is gradually prepared for each successive phase of view as it presents itself。 But in the balloon survey； cities； villages； and vast tracts for observation spring almost magically before the eye； and change in aspect and size so pleasingly that bewilderment first and then unbounded admiration is sure to follow。〃
The ice was now fairly broken； and； not suffering professional duties to be any hindrance； Coxwell began to make a series of ascents under the leadership of two rival balloonists； Gale and Gypson。 One voyage made with the latter he describes as leading to the most perilous descent in the annals of aerostation。 This was the occasion； given above； on which Albert Smith was a passenger； and which that talented writer describes in his own fashion。 He does not； however； add the fact； worthy of being chronicled； that exactly a week after the appalling adventure Gypson and Coxwell； accompanied by a Captain whose name does not transpire； and loaded with twice the previous weight of fireworks； made a perfectly successful night ascent and descent in the same balloon。
It is very shortly after this that we find Coxwell seduced into undertaking for its owners the actual management of a balloon； the property of Gale； and now to be known as the 〃Sylph。〃 With this craft he practically began his career as a professional balloonist； and after a few preliminary ascents made in England； was told off to carry on engagements in Belgium。
A long series of ascents was now made on the Continent； and in the troubled state of affairs some stirring scenes were visited； not without some real adventure。 One occasion attended with imminent risk occurred at Berlin in 1851。 Coxwell relates that a Prussian labourer whom he had dismissed for bad conduct； and who almost too manifestly harboured revenge； nevertheless begged hard for a re…engagement； which； as the man was a handy fellow； Coxwell at length assented to。 He took up three passengers beside himself； and at an elevation of some 3；000 feet found it necessary to open the valve； when； on pulling the cord； one of the top shutters broke and remained open； leaving a free aperture of 26 inches by 12 inches； and occasioning such a copious discharge of gas that nothing short of a providential landing could save disaster。 But the providential landing came； the party falling into the embrace of a fruit tree in an orchard。 It transpired afterwards that the labourer had been seen to tamper with the valve； the connecting lines of which he had partially severed。
Returning to England in 1852 Coxwell； through the accidents inseparable from his profession； found himself virtually in possession of the field。 Green； now advanced in years； was retiring from the public life in which he had won so much fame and honour。 Gale was dead； killed in an ascent at Bordeaux。 Only one aspirant contested the place of public aeronautone Goulston； who had been Gale's patron。 Before many months； however； he too met with a balloonist's death； being dashed against some stone walls when ascending near Manchester。
It will not be difficult to form an estimate of how entirely the popularity of the balloon was now reestablished in England； from the mere fact that before the expiration of the year Coxwell had been called upon to make thirty…six voyages。 Some of these were from Glasgow； and here a certain coincidence took place which is too curious to be omitted。 A descent effected near Milngavie took place in the same field in which Sadler； twenty…nine years before； had also descended； and the same man who caught the rope of Mr。 Sadler's balloon performed the same service once again for a fresh visitor from the skies。
The following autumn Coxwell； in fulfilling one out of many engagements； found himself in a dilemma which bore resemblance in a slight degree to a far more serious predicament in which the writer became involved； and which must be told in due place。 The preparations for the ascent； which was from the Mile End Road； had been hurried； and after finally getting away at a late hour in the evening； it was found that the valve line had got caught in a fold of the silk； and could not be operated。 In consequence； the balloon was； of necessity； left to take its own chance through the night； and； after rising to a considerable height； it slowly lost buoyancy during the chilly hours； and； gradually settling； came to earth near Basingstoke； where the voyager； failing to get help or shelter； made his bed within his own car； lying in an open field； as other aeronauts have had to do in like circumstances。
Coxwell tells of a striking phenomenon seen during that voyage。 〃A splendid meteor was below the car； and apparently about 600 feet distant。 It was blue and yellow； moving rapidly in a N。E。 direction； and became extinguished without noise or sparks。〃
CHAPTER XI。 THE BALLOON IN THE SERVICE OF SCIENCE。
At this point we must； for a brief while； drop the history of the famous aeronaut whose early career we have been briefly sketching in the last chapter； and turn our attention to a new feature of English ballooning。 We have； at last； to record some genuinely scientific ascents； which our country now； all too tardily； instituted。 It was the British Association that took the initiative； and the two men they chose for their purpose were both exceptionally qualified for the task they had in hand。 The practical balloonist was none other than the veteran Charles Green； now in his sixty…seventh year； but destined yet to enjoy nearly twenty years more of life。 The scientific expert was Mr。 John Welsh； well fitted for the projected work by long training at Kew Observatory。 The balloon which they used is itself worthy of mention； being the great Nassau Balloon of olden fame。
Welsh was quick to realise more clearly than any former experimentalist that on account of the absence of breeze in a free balloon； as also on account of great solar radiation； the indications of thermometers would； without special precautions； be falsified。 He therefore invented a form of aspirating thermometer； the earliest to be met with； and far in advance of any that were subsequently used by other scientists。 It consisted of a polished tube； in which thermometers were enclosed； and through which a stream of air was forced by bellows。
The difficulty of obtaining really accurate readings where thermometers are being quickly transported through varying temperatures is generally not duly appreciated。 In the case of instruments carried m a balloon it should be remembered that the balloon itself conveys； clinging about it； no inconsiderable quantity of air； brought from other levels； while the temperature of its own mass will be liable to affect any thermometer in close neighbourhood。 Moreover； any ordinary form of thermometer is necessarily sluggish in action； as may be readily noticed。 If； for example； one be carried from a warm room to a cold passage； or vice versa it will be seen that the column moves very deliberately； and quite a long interval will elapse before it reaches its final position； the cause being that the entire instrument； with any stand or mounting that it may have； will have to adapt itself to the change of temperature before a true record will be obtained。 This difficulty applies unavoidably to all thermometers in some degree； and the skill of instrument makers has been taxed to reduce the errors to a minimum。 It is necessary； in any case； that a constant stream of surrounding air should play upon the instrument； and though this is most readily effected when instruments are carried aloft by kites； yet even thus it is thought that an interval of some minutes has to elapse before any form of thermometer will faithfully record any definite change of temperature。 It is on this account that some allowance must be made for observations which will； in due place； be recorded of scientific explorers； the point to be borne in mind being that；
