Let us suppose ourselves looking through a glass, eye at the eye-piece, at a balloon. It is large, gigantic, monstrous, the aërostat of to-day. Turn the glass, end for end. The balloon is reduced, and becomes a mere point, imperceptible, lost. Such is, from our point of view, the balloon of the morrow. It is well for the present to use the balloon as a supplementary sustaining instrument; but let us always keep in mind that we shall thank it as soon as possible for its services and show it the door. A hypothesis should be to the physicist simply a provisional artifice for the convenient grouping or explaining of a number of determined phenomena; and, to our view, a balloon is a similar artifice, the present uses of which may be valuable.
We had the honor some years ago of becoming acquainted with MM. de la Landelle and Ponton d'Amécourt, warm partisans and advocates of the doctrine of machines heavier than the air, which originated, according to classical traditions, with Architas. They convinced us, and we have since been their fervent disciple. We are, in fact, a persistent admirer of the simple processes employed in Nature and used in a marvelous way by birds to sustain themselves in the air and guide their flight, and specious calculations have never caused us to doubt the possibility of a solution of the problem of locomotion in the air by wholly mechanical means; and we have long regarded the solution of it as depending solely on the discovery of a powerful and light motor. How many examples does the history of natural philosophy present us of calculations that have deceived—either because their starting-point was false, or because we were mistaken in interpreting the results!
What good does it do to descant on the forms and the details of an air-machine when its most essential part, its soul we might say—its motor—has not been found? Could we give a rational theory of telephony before Bell invented his electric telephone, or of the transmission of force to great distances before the creation of the Gramme machine?
We have received numerous letters during the last twenty years from authors and inventors desiring to submit to us their projects and arrangements of propellers. "It is all very well," we have told them, "but, before sending me anything—have you a motor?" "A motor? No, sir; we have thought about it, indeed, but have depended on you for that," "If I had a motor," I would reply, "I should have no need of your apparatus; I have a thousand of them, and my only trouble is in choosing between them." The motor, in fact, is the essential thing; having that, it is a minor affair whether one prefers the aëroplane, the helicopter, or the aviator; it is a question of return—a question that must be looked into, but which is strictly subordinate to the nature of
