heaviest loads, is certainly very ingenious; of its conclusiveness, we
must leave our readers to judge for themselves.

'Progression from the simple to the composite, says M. Pétin, is the
universal law. In the works of nature, the action of this law is
everywhere visible; and man, in his works, follows the path thus
consecrated by the footsteps of the Creator. Thus we find, he
continues, that the point multiplied by itself produces the line; the
line, in like manner, produces the plane; and the plane, the cube; an
ascending series, which he conceives to have its exact analogy in that
furnished by the earth, the water, and the air, considered as _media_
of locomotion. In other words, the point, or primary germ of
extension, corresponds, according to the theory of M. Pétin, with the
fulcrum, or primary condition of locomotion; the line, first and
simplest form of extension, corresponds with locomotion on the surface
of the earth, where, owing to topographic inequalities, and other
obstacles, locomotion can take place only in its first and simplest
mode--namely, in a linear direction; the plane, produced by the
movement of the line, and constituting a higher term of superficial
development, corresponds with locomotion upon the water, whose
unencumbered surface, which can be traversed in every direction,
presents a locomotive medium, the facilities of which, compared with
those offered by the surface of the earth, increase in the ratio of
the difference of extension between the line and the plane.

'The cube, product of the plane multiplied by itself, corresponds with
locomotion in the air, where the aëronaut, being surrounded on every
side by fulcra furnished by the various strata of the atmosphere,
moves at will in every direction; pressing on the higher strata in
ascending, on the lower in descending, on the lateral in turning to