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me unexpectedly； and considerably unsettle the nerves of any holiday passenger。 I could tell of a 〃captive〃 that had been behaving itself creditably on a not very settled day suddenly swooping over a roadway and down into public gardens； where it lay incontinently along the ground； and then； before the astonished passengers could attempt to alight； it was seized with another mood； and； mounting once again majestically skyward； submitted to be hauled down with all becoming grace and ease。 It is owing to their vagaries and want of manageability that； as will be shown； 〃captives〃 are of uncertain use in war。 On the other hand； a free balloon is exempt from such disadvantages； and at moderate heights not the smallest feeling of nausea is ever experienced。 The only unpleasant sensation； and that not of any gravity； ever complained of； is a peculiar tension in the ears experienced in a rapid ascent； or more often； perhaps； in a descent。 The cause； which is trivial and easily removed； should be properly understood； and cannot be given in clearer language than that used by Professor Tyndall：〃Behind the tympanic membrane exists a cavitythe drum of the earin part crossed by a series of bones； and in part occupied by air。 This cavity communicates with the mouth by means of a duct called the Eustachian tube。 This tube is generally closed； the air space behind the tympanic membrane being thus cut off from the external air。 If； under these circumstances； the external air becomes denser； it will press the tympanic membrane inwards； if； on the other hand； the air on the other side becomes rarer； while the Eustachian tube becomes closed； the membrane will be pressed outwards。 Pain is felt in both cases； and partial deafness is experienced。。。。 By the act of swallowing the Eustachian tube is opened； and thus equilibrium is established between the external and internal pressure。〃
Founded on physical facts more or less correct in themselves； come a number of tales of olden days； which are at least more marvellous than credible； the following serving as an example。 The scientific truth underlying the story is the well…known expedient of placing a shrivelled apple under the receiver of an air pump。 As the air becomes rarefied the apple swells； smooths itself out； and presently becomes round and rosy as it was in the summer time。 It is recorded that on one occasion a man of mature years made an ascent； accompanied by his son； and； after reaching some height； the youth remarked on how young his father was looking。 They still continued to ascend； and the same remark was repeated more than once。 And at last； having now reached attenuated regions； the son cried in astonishment； 〃Why； dad； you ought to be at school！〃 The cause of this remark was that in the rarefied air all the wrinkles had come out of the old man's face； and his cheeks were as chubby as his son's。
This discussion of old ideas should not be closed without mention of a plausible plea for the balloon made by Wise and others on the score of its value to health。 Lofty ascents have proved a strain on even robust constitutionsthe heart may begin to suffer； or ills akin to mountain sickness may intervene before a height equal to that of our loftiest mountain is reached。 But many have spoken of an exhilaration of spirits not inferior to that of the mountaineer； which is experienced； and without fatigue； in sky voyages reasonably indulged inof a light…heartedness； a glow of health； a sharpened appetite； and the keen enjoyment of mere existence。 Nay； it has been seriously affirmed that 〃more good may be got by the invalid in an hour or two while two miles up on a fine summer's day than is to be gained in an entire voyage from New York to Madeira by sea。〃
CHAPTER X。 THE COMMENCEMENT OF A NEW ERA。
Resuming the roll of progressive aeronauts in England whose labours were devoted to the practical conquest of the air； and whose methods and mechanical achievements mark the road of advance by which the successes of to…day have been obtained； there stand out prominently two individuals； of whom one has already received mention in these pages。
The period of a single life is seldom sufficient to allow within its span the full development of any new departure in art or science； and it cannot； therefore； be wondered at if Charles Green； though reviving and re…modelling the art of ballooning in our own country； even after an exceptionally long and successful career； left that pursuit to which he had given new birth virtually still in its infancy。
The year following that in which Green conducted the famous Nassau voyage we find him experimenting in the same balloon with his chosen friend and colleague； Edward Spencer； solicitor； of Barnsbury； who； only nine years later； compiles memoranda of thirty…four ascents； made under every variety of circumstance； many being of a highly enterprising nature。 We find him writing enthusiastically of the raptures he experienced when sailing over London in night hours； of lofty ascents and extremely low temperatures； of speeding twenty…eight miles in twenty minutes； of grapnel ropes breaking； and of a cross…country race of four miles through woods and hedges。 Such was Mr。 Spencer the elder； and if further evidence were needed of his practical acquaintance with； as well as personal devotion to； his adopted profession of aeronautics； we have it in the store of working calculations and other minutiae of the craft； most carefully compiled in manuscript by his own hand； these memoranda being to this day constantly consulted by his grandsons； the present eminent aeronauts； Messrs。 Spencer Brothers； as supplying a manual of reliable data for the execution of much of the most important parts of their work。
In the terrific ordeal and risk entailed by the daring and fatal parachute descent of Cocking； Green required an assistant of exceptional nerve and reliability； and； as has been recorded； his choice at once fell on Edward Spencer。 In this choice it has already been shown that he was well justified； and in the trying circumstances that ensued Green frankly owns that it was his competent companion who was the first to recover himself。 A few years later； when a distinguished company； among whom were Albert Smith and Shirley Brooks； made a memorable ascent from Cremorne； Edward Spencer is one of the select party。
Some account of this voyage should be given； and it need not be said that no more graphic account is to be found than that given by the facile pen of Albert Smith himself。 His personal narrative also forms an instructive contrast to another which he had occasion to give to the world shortly afterwards； and which shall be duly noticed。 The enthusiastic writer first describes； with apparent pride； the company that ascended with him。 Besides Mr。 Shirley Brooks； there were Messrs。 Davidson； of the Garrick Club； Mr。 John Lee； well known in theatrical circles； Mr。 P。 Thompson； of Guy's Hospital； and othersten in all； including Charles Green as skipper； and Edward Spencer； who； sitting in the rigging； was entrusted with the all…important management of the valve rope。
〃The first sensation experienced；〃 Albert Smith continues； 〃was