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s； with tremendous oscillations of the car； until the balloon is borne to earth in a torrent of rain。 We fancy that many practical balloonists will hardly endorse this description。
But we have another； relating to one of the most distinguished aeronauts； M。 Eugene Godard； who； in an ascent with local journalists； was caught in a thunderstorm。 Here we are toldpresumably by the journaliststhat 〃twice the lightning flashed within a few yards of the terror…stricken crew。〃
Once again； in an ascent at Derby； a spectator writes：〃The lightning played upon the sphere of the balloon； lighting it up and making things visible through it。〃 This； however； one must suppose； can hardly apply to the balloon when liberated。
But a graphic description of a very different character given in the 〃Quarterly Journal of the Royal Meteorological Society〃 for January； 1901； is of real value。 It appears that three lieutenants of the Prussian Balloon Corps took charge of a balloon that ascended at Berlin； and； when at a height of 2；300 feet； became enveloped in the mist； through which only occasional glimpses of earth were seen。 At this point a sharp； crackling sound was heard at the ring； like the sparking of a huge electrical machine； and； looking up； the voyagers beheld sparks apparently some half…inch thick； and over two feet in length； playing from the ring。 Thunder was heard； butand this may have significanceonly before and after the above phenomenon。
Another instructive experience is recorded of the younger Green in an ascent which he made from Frankfort…on…the…Maine。 On this occasion he relates that he encountered a thunderstorm； and at a height of 4；400 feet found himself at the level where the storm clouds were discharging themselves in a deluge。 He seems to have had no difficulty in ascending through the storm into the clear sky above； where a breeze from another quarter quickly carried him away from the storm centre。
This co…existence； or conflict of opposite currents； is held to be the common characteristic； if not the main cause； of thunderstorms； and tallies with the following personal experience。 It was in typical July weather of 1900 that the writer and his son； accompanied by Admiral Sir Edmund Fremantle and Mr。 Percival Spencer； made an evening ascent from Newbury。 It had been a day of storms； but about 5 p。m。； after what appeared to be a clearing shower； the sky brightened； and we sailed up into a cloudless heaven。 The wind； at 3；000 feet； was travelling at some thirty miles an hour； and ere the distance of ten miles had been covered a formidable thunder pack was seen approaching and coming up dead against the wind。 Nothing could be more evident than that the balloon was travelling rapidly with a lower wind； while the storm was being borne equally rapidly on an upper and diametrically opposite current。 It proved one of the most severe thunderstorms remembered in the country。 It brooded for five hours over Devizes； a few miles ahead。 A homestead on our right was struck and burned to the ground； while on our left two soldiers were killed on Salisbury Plain。 The sky immediately overhead was； of course； hidden by the large globe of the balloon； but around and beneath us the storm seemed to gather in a blue grey mist； which quickly broadened and deepened till； almost before we could realise it； we found ourselves in the very heart of the storm； the lightning playing all around us； and the sharp hail stinging our faces。
The countrymen below described the balloon as apparently enveloped by the lightning； but with ourselves； though the flashes were incessant； and on all sides； the reverberations of the thunder were not remarkable； being rather brief explosions in which they resembled the thunder claps not infrequently described by travellers on mountain heights。
The balloon was now descending from a double cause： the weight of moisture suddenly accurnulated on its surface； and the very obvious downrush of cold air that accompanied the storm of pelting hail。 With a very limited store of ballast； it seemed impossible to make a further ascent； nor was this desirable。 The signalling experiments on which we were intent could not be carried on in such weather。 The only course was to descend； and though this was not at once practicable； owing to Savernake Forest being beneath us； we effected a safe landing in the first available clearing。
As has been mentioned； Mr。 Glaisher and other observers have recorded several remarkable instances of opposite wind currents being met with at moderate altitudes。 None； however； can have been more noteworthy or surprising than the following experience Of the writer on Whit Monday of 1899。 The ascent was under an overcast sky； from the Crystal Palace at 3 p。m。； at which hour a cold drizzle was settling in with a moderate breeze from the east。 Thus； starting from the usual filling ground near the north tower； the balloon sailed over the body of the Palace； and thence over the suburbs towards the west till lost in the mist。 We then ascended through 1；500 feet of dense； wetting cloud； and； emerging in bright sunshine； continued to drift for two hours at an average altitude of some 3；000 feet； 1；000 feet below us was the ill…defined； ever changing upper surface of the dense cloud floor； and it was no longer possible to determine our course； which we therefore assumed to have remained unchanged。 At length； however； as a measure of prudence； we determined to descend through the clouds sufficiently to learn something of our whereabouts； which we reasonably expected to be somewhere in Surrey or Berks。 On emerging； however； below the cloud； the first object that loomed out of the mist irnmediately below us was a cargo vessel； in the rigging of which our trail rope was entangling itself。 Only by degrees the fact dawned upon us that we were in the estuary of the Thames； and beating up towards London once again with an cast wind。 Thus it became evident that at the higher level； unknown to ourselves； we had been headed back on our course； for two hours； by a wind diametrically opposed to that blowing on the ground。
Two recent developments of the hot…air war balloon suggest great possibilities in the near future。 One takes the form of a small captive； carrying aloft a photographic camera directed and operated electrically from the ground。 The other is a self…contained passenger balloon of large dimensions； carrying in complete safety a special petroleum burner of great power。 These new and important departures are mainly due to the mechanical genius of Mr。 J。 N。 Maskelyne； who has patented and perfected them in conjunction with the writer。
CHAPTER XXVIII。 THE CONSTITUTION OF THE AIR。
Some fair idea of the conditions prevailing in the upper air may have been gathered from the many and various observations already recorded。 Stating the case broadly； we may assert that the same atmospheric changes with which we are familiar at the level of the earth are to be found also at all accessible heights； equally extensive and equally sudden。
Standing on an open heath on a gusty day； we may often note the rhythmic buffeting of the wind； resembling the assault of rolling bi