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rry out any required manoeuvre in such atmospheric conditions as generally prevail。 If； even in calm and favourable weather； more often than not motors break down； or gear carries away； what hope is there for any aerial craft which would attempt to battle with such wind currents as commonly blow aloft？
And when we turn to the balloon proper； are chances greatly improved？ The eminently practical aeronaut； John Wise； as was told in Chapter XII。； prepared a scheme for the reduction of Vera Cruz by the agency of a balloon。 Let us glance at it。 A single balloon was to suffice； measuring 100 feet in diameter； and capable of raising in the gross 30；000 lbs。 To manoeuvre this monstrous engine he calculates he would require a cable five miles long； by means of which he hoped； in some manner； to work his way directly over the fortress； and to remain poised at that point at the height of a mile in the sky。 Once granted that he could arrive and maintain himself at that position； the throwing out of combustibles would be simple； though even then the spot where they would alight after the drop of a mile would be by no means certain。 It is also obvious that a vast amount of gas would have to be sacrificed to compensate for the prodigal discharge of ballast in the form of missiles。
The idea of manoeuvring a balloon in a wind； and poising it in the manner suggested； is； of course； preposterous； and when one considers the attempt to aim bombs from a moving balloon high in air the case becomes yet more absurd。 Any such missile would partake of the motion of the balloon itself； and it would be impossible to tell where it would strike the earth。
To give an example which is often enough tried in balloon travel when the ground below is clear。 A glass bottle （presumably empty） is cast overboard and its fall watched。 It is seen not to be left behind； but to keep pace with the balloon； shrinking gradually to an object too small to be discerned； except when every now and then a ray of sunlight reflected off it reveals it for a moment as it continues to plunge downwards。 After a very few seconds the impression is that it is about to reach the earth； and the eye forms a guess at some spot which it will strike； but the spot is quickly passed； and the bottle travels far beyond across a field； over the further fence； and vastly further yet； indeed； inasmuch as to fall a mile in air a heavy body may take over twenty secondsand twenty seconds is long to those who watchit is often impossible to tell to two or three fields where it will finally settle。
All this while the risk that a balloon would run of being riddled by bullets； shrapnel； or pom…poms has not been taken into account； and as to the estimate of this risk there is some difference of opinion。 The balloon corps and the artillery apparently approach the question with different bias。 On the one hand； it is stated with perfect truth that a free balloon； which is generally either rising or falling； as well as moving across country； is a hard object to hit； and a marksman would only strike it with a chance or blundering shot； but； on the other hand let us take the following report of three years ago。
The German artillery had been testing the efficiency of a quick…firing gun when used against a balloon； and they decided that the latter would have no chance of escape except at night。 A German kite…balloon was kept moving at an altitude of 600 metres； and the guns trained upon it were distant 3；000 metres。 It was then stated that after the third discharge of the rapid firing battery the range was found； when all was at once over with the balloon； for； not only was it hit with every discharge； but it was presently set on fire and annihilated。
But； in any case； the antique mode of keeping a balloon moored at any spot as a post of observation must be abandoned in modern warfare。 Major Baden…Powell； speaking from personal experience in South Africa； has shown how dangerous； or else how useless； such a form of reconnaissance has become。 〃I remember；〃 he says； 〃at the battle of Magersfontein my company was lying down in extended order towards the left of our line。 We were perfectly safe from musketry fire； as we lay； perhaps； two miles from the Boer trenches； which were being shelled by some of our guns close by。 The enemy's artillery was practically silent。 Presently； on looking round； I descried our balloon away out behind us about two miles off。 Then she steadily rose and made several trips to a good height； but what could be seen from that distance？ When a large number of our troops were ranged up within 800 yards of the trenches； and many more at all points behind them； what useful information could be obtained by means of the balloon four miles off？〃
The same eminent authority insists on the necessity of an observing war balloon making short ascents。 The balloon； in his opinion； should be allowed to ascend rapidly to its full height； and with as little delay as possible be hauled down again。 Under these conditions it may then be well worth testing whether the primitive form of balloon； the Montgolfier； might not be the most valuable。 Instead of being made； as the war balloon is now； of fragile material； and filled with costly gas difficult to procure； and which has to be conveyed in heavy and cumbersome cylinders； a hot air balloon could be rapidly carried by hand anywhere where a few men could push their way。 It is of strong material； readily mended if torn； and could be inflated for short ascents； if not by mere brush wood； then by a portable blast furnace and petroleum。
But there is a further use for balloons in warfare not yet exploited。 The Siege of Paris showed the utility of free balloons； and occasions arise when their use might be still further extended。 The writer pointed out that it might have been very possible for an aeronaut of experience； by choosing the right weather and the right position along the British lines； to have skilfully manoeuvred a free balloon by means of upper currents； so as to convey all…important intelligence to besieged Mafeking； and he proved that it would have sufficed if the balloon could have been 〃tacked〃 across the sky to within some fifteen miles of the desired goal。
The mode of signalling which he proposed was by means of a 〃collapsing drum；〃 an instrument of occasional use in the Navy。 A modification of this instrument； as employed by the writer； consisted of a light； spherical； drum…shaped frame of large size； which； when covered with dark material and hung in the clear below the car of a lofty balloon； could be well seen either against blue sky or grey at a great distance。 The so…called drum could； by a very simple contrivance； readily worked from the car； be made to collapse into a very inconspicuous object； and thus be capable of displaying Morse Code signals。 A long pause with the drum extendedlike the long wave of a signalling flagwould denote a 〃dash；〃 and a short pause a 〃dot；〃 and these motions would be at once intelligible to anyone acquainted with the now universal Morse Code system。
Provided with an apparatus of the kind； the writer made an ascent from Newbury at a time when the military camps were lying on Salisbury Plain at a distance of nearly twenty miles to the south…west。 The ground wind up to 2；500 feet on starting was nearly due north； and would have defeated the attempt； again； the air stream blowing above that height was nearly due east； which again would have proved unsuitable。 But it was manifestly possible to utilise the two currents； and with good luck to zig…zag one's course so as to come within easy signalling distance of the various camps； and； as a matter of fact； we actually passed immediately over Bulford Camp； with which we exchanged signals； while two other camps lay close to right and left of us。 Fortune favouring us； we had actually hit our mark； though it would have been sufficient for the experiment had our course lain within ten miles right or left。
Yet a further use for the balloon in warfare remains untried in this country。 Acting under the advice of experts in the Service； the writer； in the early part of the present year； suggested to the Admiralty the desirabilit