the dominion of the air-第33节
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e popular appreciation。 But enthusiasm was by no means the universal attitude with which the world regarded aerial enterprise。 A remarkable and instructive instance is given to the contrary by M。 W。 de Fonvielle himself。
He records an original ballooning exploit； organised at Algiers； which one might have supposed would have caused a great sensation； and to which he himself had called public attention in the local journals。 The brothers Braguet were to make an ascent from the Mustapha Plain in a small fire balloon heated with burning straw； and this risky performance was successfully carried out by the enterprising aeronauts。 But； to the onlooker； the most striking feature of the proceeding was the fact that while the Europeans present regarded the spectacle with curiosity and pleasure； the native Mussulmans did not appear to take the slightest interest in it； 〃And this；〃 remarked de Fonvielle； 〃was not the first time that ignorant and fanatic people have been noted as manifesting complete indifference to balloon ascents。 After the taking of Cairo； when General Buonaparte wished to produce an effect upon the inhabitants； he not only made them a speech； but supplemented it with the ascent of a fire balloon。 The attempt was a complete failure； for the French alone looked up to the clouds to see what became of the balloon。〃
In the summer of 1867 an attempt was made to revive the long extinct Aeronautic Company of France； established by De Guyton。 The undertaking was worked with considerable energy。 Some forty or fifty active recruits were pressed into the service； a suitable captive balloon was obtained； thousands of spectators came to watch the evolutions； and many were found to pay the handsome fee of 100 francs for a short excursion in the air。 For all this； the effort was entirely abortive； and the ballooning corps； as such； dropped out of existence。
A little while after this de Fonvielle； on a visit to England； had a most pathetic interview with the veteran Charles Green； who was living in comfortable retirement at Upper Holloway。 The grand old man pointed to a well…filled portfolio in the corner of his room； in which； he said； were accounts of all his travels； that would require a lifetime to peruse and put in order。 Green then took his visitor to the end of the narrow court； and； opening the door of an outhouse； showed him the old Nassau balloon。 〃Here is my car；〃 he said； touching it with a kind of solemn respect； 〃which； like its old pilot； now reposes quietly after a long and active career。 Here is the guide rope which I imagined in former years； and which has been found very useful to aeronauts。。。。 Now my life has past and my time has gone by。。。。 Though my hair is white and my body too weak to help you； I can still give you my advice； and you have my hearty wishes for your future。〃
It was but shortly after this； on March 26； 1870； that Charles Green passed away in the 85th year of his age。
De Fonvielle's colleague； M。 Gaston Tissandier； was on one occasion accidentally brought to visit the resting place of the earliest among aeronauts； whose tragic death occurred while Charles Green himself was yet a boy。 In a stormy and hazardous descent Tissandier； under the guidance of M。 Duruof； landed with difficulty on the sea coast of France； when one of the first to render help was a lightkeeper of the Griz…nez lighthouse； who gave the information that on the other side of the hills； a few hundred yards from the spot where they had landed； was the tomb of Pilatre de Rozier； whose tragical death has been recorded in an early chapter。 A visit to the actual locality the next day revealed the fact that a humble stone still marked the spot。
Certain scientific facts and memoranda collected by the talented French aeronaut whom we are following are too interesting to be omitted。 In the same journey to which we have just referred the voyagers； when nearly over Calais； were witnesses from their commanding standpoint of a very striking phenomenon of mirage。 Looking in the direction of England； the far coast line was hidden by an immense veil of leaden…coloured cloud； and； following this cloud wall upward to detect where it terminated； the travellers saw above it a greenish layer like that of the surface of the sea； on which was detected a little black point suggesting a walnut shell。 Fixing their eyes on this black spot； they presently discerned it to be a ship sailing upside down upon an aerial ocean。 Soon after； a steamer blowing smoke； and then other vessels； added themselves to the illusory spectacle。
Another wonder detected； equally striking though less uncommon； was of an acoustical nature； the locality this time being over Paris。 The height of the balloon at this moment was not great； and； moreover； was diminishing as it settled down。 Suddenly there broke in upon the voyagers a sound as of a confused kind of murmur。 It was not unlike the distant breaking of waves against a sandy coast； and scarcely less monotonous。 It was the noise of Paris that reached them； as soon as they sank to within 2；600 feet of the ground； but it disappeared at once when they threw out just sufficient ballast to rise above that altitude。
It might appear to many that so strange and sudden a shutting out of a vast sound occurring abruptly in the free upper air must have been more imaginary than real； yet the phenomenon is almost precisely similar to one coming within the experience the writer； and vouched for by his son and daughter； as also by Mr。 Percival Spencer； all of whom were joint observers at the time； the main point of difference in the two cases being the fact that the 〃region of silence〃 was recorded by the French observers as occurring at a somewhat lower level。 In both cases there is little doubt that the phenomenon can be referred to a stratum of disturbed or non…homogeneous air； which may have been very far spread； and which is capable of acting as a most opaque sound barrier。
Attention has often been called in these pages to the fact that the action of the sun on an inflated balloon； even when the solar rays may be partially obscured and only operative for a few passing moments； is to give sudden and great buoyancy to the balloon。 An admirable opportunity for fairly estimating the dynamic effect of the sun's rays on a silk globe； whose fabric was half translucent； was offered to the French aeronauts when their balloon was spread on the grass under repair； and for this purpose inflated with the circumambient air by means of a simple rotatory fan。 The sun coming out； the interior of the globe quickly became suffocating； and it was found that； while the external temperature recorded 77 degrees； that of the interior was in excess of 91 degrees。
CHAPTER XVII。 ADVENTURE AND ENTERPRISE。
A balloon which has become famous in history was frequently
used in the researches of the French aeronauts mentioned in our last chapter。 This was known as 〃The Giant；〃 the creation of M。 Nadar； a progressive and practical aeronaut； who had always entertained ambitious ideas about aerial travel。
M。 Nadar had been editor of L'Aeronaut； a French journal devoted to the advancement of aerostation generally。 He had also strongly expressed his own views respecting the possibility of constructing air ships that should be subject to control and guidance when winds were blowing。 His great contention was that the dirigible air ship would； like a bird； have to be made heavier than the medium in which it was to fly。 As he put it； a balloon could never properly become a vessel。 It would only be a buoy。 In spite of any number of accessories； paddles； wings； fans； sails； it could not possibly prevent the wind from bodily carrying away the whole concern。
After this strong expression of opinion； it may appear somewhat strange that such a bold theoriser should at once have set himself to construct the largest gas balloon on record。 Such； however； was the case and the reason urged was not otherwise than plausible。 For； seeing that a vast sum of money would be needed to put his theories into practice； M。 Nadar conceived the idea of first constructing a balloon so unique and unrivalled that it should compel public attention in a way that no other balloon had done before； and so by popular exhibitions bring to his hand such sums as he required。 A proper idea of the scale of this huge machine can be easily gathered。 The largest balloons at present exhibited in this country are seldom much in excess of 50；000 cubic feet capacity。 Compared with these the 〃Great Nassau Balloon；〃 built by Charles Green； which has been already sufficiently described； was a true leviathan； while Coxwell's 〃Mammoth〃 was larger yet； possessing a content； when fully inflated； of no less than 93；000 cubic feet； and measuring over 55 feet in diameter。 This； however； as will be seen； was but a mere pigmy when compared with 〃The Giant；〃 which； measuring some 74 feet in diameter； possessed the prodigious capacity of 215；000 cubic feet。
But the huge craft possessed another novelty besides that of exceptional size。 It was provided with a subsidiary balloon； called the 〃Compensator；〃 and properly the idea of M。 L。 Godard； the function of which wa
