the dominion of the air-第34章
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few minutes； Mr。 Shadbolt succumbed later； and both remaining passengers sustained terrible injuries。
Few balloon mishaps； unattended with fatal results； have proved more exciting than the following。 A large party had ascended from Belfast； in a monster balloon； under the guidance of Mr。 Coxwell； on a day which was very unfit for the purpose by reason of stormy weather。 A more serious trouble than the wind； however； lay in several of the passengers themselves； who seem to have been highly excitable Irishmen； incapable at the critical moment of quietly obeying orders
The principal hero of the story； a German。 Mr。 Runge； in writing afterwards to the Ulster Observer； entirely exonerates Mr。 Coxwell from any blame； attributing his mischances solely to the reprehensible conduct of his companions。 On approaching the ground； Mr。 Coxwell gave clear instructions。 The passengers were to sit down in an unconstrained position facing each other； and be prepared for some heavy shocks。 Above all things they were to be careful to get out one by one； and on no account to leave hold of the car。 Many of the passengers； however； refused to sit down； and； according to Mr。 Runge； 〃behaved in the wildest manner； losing completely their self…control。 Seizing the valve rope themselves； they tore it away from its attachment； the stronger pushing back the weaker； and refusing to lend help when they had got out。 In consequence of this the car； relieved of their weight； tore away from the grasp of Mr。 Coxwell and those who still clung to it； and rose above the trees； with Mr。 Runge and one other passenger； Mr。 Halferty； alone within。 As the balloon came earthwards again； they shouted to the countrymen for succour； but without the slightest avail； and presently； the anchor catching； the car struck the earth with a shock which threw Mr。 Halferty out on the ground； leaving Mr。 Runge to rise again into the air； this time alone。〃 He thus continues the story：
〃The balloon moved on； very soon； in a horizontal direction straight towards the sea； which we were then rapidly nearing。 Coming to a farm； I shouted out to the people standing there。 Some women； with their quick humane instincts； were the first to perceive my danger； and exhorted the men to hurry to my assistance； they themselves running as fast as they could to tender what little help they might be able to give me。 The anchor stuck in a willow tree。 I shouted out to the people below to secure the cable and anchor by ropes； which they did。 The evening was now beautifully still； the breeze had died away； and the balloon was swinging calmly at her moorings above the farmhouse。 One of the men asked me whether I had a rope with me； and how I intended to get out。 I told them only to take care of the cable； because the balloon would settle down by herself before long。 I was congratulating myself on a speedy escape from my dangerous position。 I had not counted on the wind。 A breeze in about six or eight minutes sprang up； tossed the balloon about like a large sail； then a crash； andthe anchor was loose again。 It tore through the trees； flinging limbs and branches about like matches。 It struck the roof of the farmhouse； splintering the chimneys and tiles like glass。
〃On I went； I came near another farm； shouted out for help； and told the men to secure the anchor to the foot of a large tree close by。 The anchor was soon made fast； but this was only a momentary relief。 The breeze again filled the half…empty balloon like a sail； there was a severe strain on the cable； then a dull sound； and a severe concussion of the basketthe cable； strange fatality； had broken； and the anchor； my last and only hope； was gone。 I was now carried on in a straight direction towards the sea； which was but a short distance ahead。 The anchor being lost I gave up all hope。 I sat down resigned in the car； and prepared for the end。 All at once I discovered that a side current was drifting me towards the mountain； the car struck the ground； and was dashing along at a fearful rate； knocking down stone fences and breaking everything it came in contact with in its wild career。 By…and…by the knocks became less frequent。 We were passing over a cultivated country； and the car was； as it were skimming the surface and grazing the top of the hedges。 I saw a thick hawthorn hedge at some distance before me； and the balloon rapidly sweeping towards it。 That was my only chance。 I rushed to the edge of the car and flung myself down upon the hedge。〃
CHAPTER XXI。 THE COMING OF THE FLYING MACHINE。
In the early nineties the air ship was engaging the attention of many inventors； and was making important strides in the hands of Mr。 Maxim。 This unrivalled mechanician； in stating the case； premises that a motive power has to be discovered which can develop at least as much power in proportion to its weight as a bird is able to develop。 He asserts that a heavy bird； with relatively small wingssuch as a goosecarries about 150 lb。 to the horse power； while the albatross or the vulture； possessed of proportionately greater winged surface； can carry about 250 lbs。 per horse power。
Professor Langley； of Washington； working contemporaneously； but independently of Mr。 Maxim； had tried exhaustive experiments on a rotating arm （characteristically designated by Mr。 Maxim a 〃merry…go…round〃）； thirty feet long； applying screw propellers。 He used； for the most part； small planes； carrying loads of only two or three pounds； and； under these circumstances； the weight carried was at the rate of 250 lbs。 per horse power。 His important statements with regard to these trials are that one…horse power will transport a larger weight at twenty miles an hour than at ten； and a still larger at forty miles than at twenty； and so on； that 〃the sustaining pressure of the air on a plane moving at a small angle of inclination to a horizontal path is many times greater than would result from the formula implicitly given by Newton； while； whereas in land or marine transport increased speed is maintained only by a disproportionate expenditure of power within the limits of experiment； in aerial horizontal transport the higher speeds are more economical of power than the lower ones。〃
This Mr。 Maxim is evidently ready to endorse； stating； in his own words； that birds obtain the greater part of their support by moving forward with sufficient velocity so as to be constantly resting on new air； the inertia of which has not been disturbed。 Mr。 Maxim's trials were on a scale comparable with all his mechanical achievements。 He employed for his experiments a rotating arm； sweeping out a circle； the circumference of which was 200 feet。 To the end of this arm he attached a cigar…shaped apparatus； driven by a screw； and arranged in such a manner that aero…planes could be attached to it at any angle。 These planes were on a large scale； carrying weights of from 20 lbs。 to 100 lbs。 With this contrivance he found that； whatever push the screw communicated to the aero…plane； 〃the plane would lift in a vertical direction from ten to fifteen times as much as the horizontal push that it received from the screw； and which depended upon the angle at which the plane was set； and the speed at which the apparatus was travelling through the air。〃 Next； having determined by experiment the power required to perform artificial flight； Mr。 Maxim applied himself to designing the requisite motor。 〃I constructed；〃 he states； 〃two sets of compound engines of tempered steel； all the parts being made very light and strong； and a steam generator of peculiar construction； the greater part of the heating surface consisting of small and thin copper tubes。 For fuel I employed naphtha。〃
This Mr。 Maxim wrote in 1892； adding that he was then experimenting with a large machine； having a spread of over 100 feet。 Labour； skill； and money were lavishly devoted henceforward to the great task undertaken； and it was not long before the giant flying machine； the outcome of so much patient experimenting； was completed and put to a practical trial。 Its weight was 7；500 lbs。 The screw propellers were nearly 18 feet in diameter； each with two blades； while the engines were capable of being run up to 360 horse power。 The entire machine was mounted on an inner railway track of 9 feet and an outer of 35 feet gauge； while above there was a reversed rail along which the machine would begin to run so soon as with increase of speed it commenced to lift itself off the inner track。
In one of the latest experiments it was found that when a speed of 42 miles an hour was attained all the wheels were running on the upper track； and revolving in the opposite direction from those on the lower track。 However； after running about 1；000 feet； an axle tree doubled up； and immediately afterwards the upper track broke away； and the machine； becoming liberated； floated in the air； 〃giving those on board a sensation of being in a boat。〃
The experiment proved conclusively to the inventor that a machine could be made on a large scale； in which the lifting effect should be considerably greater than the weight of the machine； and this； too； when a steam engine was the motor。 When； therefore； in the years shortly following； the steam engine was for the purposes of aerial locomotion superseded by the lighter and more suitable petrol engine； the construction of a navigable air ship became vastly more practicable。 Still； in Sir H。 Maxim's opinion； lately expressed； 〃those who seek to navigate the air by machines lighter than the air have come； practically； to the end of their tether；〃 while； on the other hand； 〃those who seek to navigate the air with machines heavier than the air have not even made a start as yet； and the possibilities before them are very great indeed。〃
As to the assertion that the aerial navigators last mentioned 〃have not even made a start as yet；〃 we can only say that Sir H。 Maxim speaks with far too much modesty。 His own colossal labours in the direction of that mode of aerial flight； which he considers to be alone feasible； are of the first importance and value； and； as far as they have gone； exhaustive。 Had his experiments been simply confined to his classical investigations of the proper form of the screw propeller his name would still have been handed down as a true pioneer in aeronautics。 His work； however； covers far wider ground； and he has； in a variety of ways； furnished practical and reliable data； which must always be an indispensable guide to every future worker in the same field。
Professor Langley； in attacking the same problem； first studied the principle and behaviour of a well…known toythe model invented by Penaud； which； driven by the tension of india…rubber； sustains itself in the air for a few seconds。 He constructed over thirty modifications of this model； and spent many months in trying from these to as certain what he terms the 〃laws of balancing leading to horizontal flight。〃 His best endeavours at first； however； showed that he needed three or four feet of sustaining surface to a pound of weight； whereas he calculated that a bird could soar with a surface of less than half a foot to the pound。 He next proceeded to steam…driven models in which for a time he f
