the dominion of the air-第56章
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ed and practical method of employing Montgolfier reconnoitring balloons； portable； readily inflated； and especially suited to the war in South Africa。 Perhaps the last letters of a private nature penned by Mr。 Coxwell were to the writer and his daughter； full of friendly and valuable suggestion； and more particularly commenting on a recent scientific aerial voyage； which proved to be not only sensational； but established a record in English ballooning。
The great train of the November meteors； known as the Leonids； which at regular periods of thirty…three years had in the past encountered the earth's atmosphere； was due； and over…due。 The cause of this； and of their finally eluding observation； need only be very briefly touched on here。 The actual meteoric train is known to travel in an elongated ellipse； the far end of which lies near the confines of the solar system； while at a point near the hither end the earth's orbit runs slantingly athwart it； forming； as it were； a level crossing common to the two orbits； the earth taking some five or six hours in transit。 Calculation shows that the meteor train is to be expected at this crossing every thirty…three and a third years； while the train is extended to such an enormous lengthtaking more than a year to draw clearthat the earth must needs encounter it ere it gets by； possibly even two years running。 There could be no absolute certainty about the exact year； nor the exact night when the earth and the meteors would foregather； owing to the uncertain disturbance which the latter must suffer from the pull of the planetary bodies in the long journey out and home again among them。 As is now known； this disturbing effect had actually dispersed the train。
The shower； which was well seen in 1866； was pretty confidently expected in 1899； and to guard against the mischance of cloudy weather； it was arranged that the writer should； on behalf of the Times newspaper； make an ascent on the right night to secure observations。 Moreover； it was arranged that he should have； as chief assistant； his own daughter； an enthusiastic lady aeronaut； who had also taken part in previous astronomical work。
Unfortunately there were two nights； those of November 14th and 15th； when the expected shower seemed equally probable； and； taking counsel with the best authorities in the astronomical world； it seemed that the only course to avoid disappointment would be to have a balloon filled and moored in readiness for an immediate start； either on the first night or on the second。
This settled the matter from the astronomical side； but there was the aeronautical side also to be considered。 A balloon of 56；000 cubic feet capacity was the largest available for the occasion； and a night ascent with three passengers and instruments would need plenty of lifting power to meet chance emergencies。 Thus it seemed that a possible delay of forty…eight hours might entail a greater leakage of gas than could be afforded。
The leakage might be expected chiefly to occur at the valve in the head of the balloon； it being extremely difficult to render any form of mechanical valve gas tight； however carefully its joints be stopped with luting。 On this account； therefore； it was determined that the balloon should be fitted with what is known as a solid or rending valve； consisting simply of balloon fabric tied hard and fast over the entire upper outlet； after the fashion of a jam pot cover。 The outlet itself was a gaping hole of over 2 feet across； but by the time its covering had been carefully varnished over all leakage was sufficiently prevented； the one drawback to this method being the fact that the liberation of gas now admitted of no regulation。 Pulling the valve line would simply mean opening the entire wide aperture； which could in no way be closed again。
The management of such a valve consists in allowing the balloon to sink spontaneously earthwards； and when it has settled near the ground； having chosen a desirable landing place； to tear open the so…called valve once and for all。
This expedient； dictated by necessity； seeming sufficient for the purpose at hand； preparations were proceeded with； and； under the management of Mr。 Stanley Spencer； who agreed to act as aeronaut； a large balloon； with solid valve； was brought down to Newbury gas works on November 14th； and； being inflated during the afternoon； was full and made snug by sundown。 But as the meteor radiant would not be well above the horizon till after midnight； the aeronautical party retired for refreshment； and subsequently for rest； when； as the night wore on； it became evident that； though the sky remained clear； there would be no meteor display that night。 The next day was overcast； and by nightfall hopelessly so； the clouds ever thickening； with absence of wind or any indication which might give promise of a change。 Thus by midnight it became impossible to tell whether any display were in progress or not。 Under these circumstances； it might have been difficult to decide when to make the start with the best show of reason。 Clearly too early a start could not subsequently be rectified； the balloon； once off； could not come back again； while； once liberated； it would be highly unwise for it to remain aloft and hidden by clouds for more than some two hours； lest it should be carried out to sea。
Happily the right decision under these circumstances was perfectly clear。 Other things being equal； the best time would be about 4 a。m。； by which period the moon； then near the full； would be getting low； and the two hours of darkness left would afford the best seeing。 Leaving； then； an efficient outlook on the balloon ground； the party enjoyed for some hours the entertainment offered them by the Newbury Guildhall Club； and at 4 a。m。 taking their seats in the car； sailed up into the calm chilly air of the November night。
But the chilliness did not last for long。 A height of 1；500 feet was read by the Davy lamp； and then we entered fogwarm； wetting fog； through which the balloon would make no progress in spite of a prodigal discharge of sand。 The fact was that the balloon； which had become chilled through the night hours； was gathering a great weight of moisture from condensation on its surface； and when； at last； the whole depth of the cloud； 1；500 feet； had been penetrated； the chill of the upper air crippled the balloon and sent her plunging down again into the mist； necessitating yet further expenditure of sand； which by this time had amounted to no less than 3 1/2 cwt。 in twenty minutes。 And then at last we reached our level； a region on the upper margin of the cloud floor； where evaporation reduced the temperature； that had recently been that of greenhouse warmth； to intense cold。
That evaporation was going on around us on a gigantic scale was made very manifest。 The surface of the vast cloud floor below us was in a perfect turmoil； like that of a troubled sea。 If the cloud surface could be compared to anything on earth it most resembled sea where waves are running mountains high。 At one moment we should be sailing over a trough； wide and deep below us； the next a mighty billow would toss itself aloft and vanish utterly into space。 Everywhere wreaths of mist with ragged fringes were withering away into empty air； and； more remarkable yet； was the conflict of wind which sent the cloud wrack flying simply in all directions。
For two hours now there was opportunity for observing at leisure all that could be made of the falling meteors。 There were a few； and these； owing to our clear； elevated region； were exceptionally bright。 The majority； too； were true Leonids； issuing from the radiant point in the 〃Sickle；〃 but these were not more numerous than may be counted on that night in any year； and served to emphasise the fact that no real display was in progress。 The outlook was maintained； and careful notes made for two hours； at the end of which time the dawn began to break； the stars went in； and we were ready to pack up and come down。
But the point was that we were not coming down。 We were at that time； 6 a。m。； 4；000 feet high； and it needs no pointing out that at such an altitude it would have been madness to tear
