The two chief methods proposed by inventors for obtaining aerial flight are by means of aeroplanes or aerocurves, driven by screw propellers, and by wings worked as in nature.

Which of these designs will practically be best it is difficult to say. It can only be by actually trying the two methods that their merits can be compared. It may be that wings are the best, as they move a larger weight of air with less velocity than a screw propeller. The slip may on this account be less.

It may be that wings are the best, as they move a larger weight of air with less velocity than a screw propeller. The slip may on this account be less.