One word more. It is possible, if not likely, that some of those friends of the narrator, for whom the account was evidently written, may still be living, and that these pages may meet their eyes. If so, they may be able to solve the few problems that have entirely baffled me, and to explain, if they so choose, the secrets to which, intentionally or through the destruction of its introductory portion, the manuscript affords no clue.
I must add that these volumes contain only the first section of the MS. record. The rest, relating the incidents of a second voyage and describing another world, remains in my hands; and, should this part of the work excite general attention, the conclusion will, by myself or by my executors, be given to the public. Otherwise, on my death, it will be placed in the library of some national or scientific institution.
... For obvious reasons, those who possessed the secret of the Apergy  had never dreamed of applying it in the manner I proposed. It had seemed to them little more than a curious secret of nature, perhaps hardly so much, since the existence of a repulsive force in the atomic sphere had been long suspected and of late certainly ascertained, and its preponderance is held to be the characteristic of the gaseous as distinguished from the liquid or solid state of matter. Till lately, no means of generating or collecting this force in large quantity had been found. The progress of electrical science had solved this difficulty; and when the secret was communicated to me, it possessed a value which had never before belonged to it.
Ever since, in childhood, I learnt that the planets were worlds, a visit to one or more of the nearest of them had been my favourite day-dream. Treasuring every hint afforded by science or fancy that bore upon the subject, I felt confident that such a voyage would be one day achieved. Helped by one or two really ingenious romances on this theme, I had dreamed out my dream, realised every difficulty, ascertained every factor in the problem. I had satisfied myself that only one thing needful was as yet wholly beyond the reach and even the proximate hopes of science. Human invention could furnish as yet no motive power that could fulfil the main requirement of the problem—uniform or constantly increasing motion in vacuo—motion through a region affording no resisting medium. This must be a repulsive energy capable of acting through an utter void. Man, animals, birds, fishes move by repulsion applied at every moment. In air or water, paddles, oars, sails, fins, wings act by repulsion exerted on the fluid element in which they work. But in space there is no such resisting element on which repulsion can operate. I needed a repulsion which would act like gravitation through an indefinite distance and in a void—act upon a remote fulcrum, such as might be the Earth