ABSTRACT
I have already said something to you regarding the early attempts to navigate the air: I find it will now be necessary for me to enter into further details of aeronautics, both to follow up my disquisitions on all other modes of locomotion, and also to complete the series of comparisons I have drawn between the present and the past. Moreover, it is needful that this subject should occupy us before we resume that history of the past that has been so much affected by it.
