rizontal_ movement; while, in the wings of the air-ship, the axis
of inclination--the pivot on which they turn--is _horizontal_,
creating _vertical_ movement. Were there but one pair of screws,
acting upon one set of inclined wings, a slight retrograde horizontal
movement would be produced in addition to the vertical movement, as
the current of blast from the screw would react upon the screw itself
with a force greater than that with which it would impinge upon the
wings, where a part of the blast will inevitably be wasted. But there
being two pairs of screws, acting in opposite directions, they will
neutralise each other's horizontal movement, while combining in the
production of vertical movement. So, at least, reasons our inventor;
but however ingenious this expedient, its efficiency may well be
doubted, when we remember the immense amount of resistance, offered by
the surface of the balloons, which would have to be overcome.

'To obtain lateral movement, the action of one pair of screws is
suspended, leaving the other pair in motion: the ship, according to
the calculation of M. Petin, will immediately describe a curve, and
turn.

'Such is the air-ship constructed by M. Petin; but, unhappily for the
demonstration of his views, the French government, either from fear of
accident, or from some other motive, has interdicted its ascension;
and the vessel which, three months ago, was ready--crew, captain, and
machinery--to attempt its advertised flight round the walls of Paris,
is still reposing, in inglorious idleness, upon its stocks in the
Chantier Marbeuf (Champs Elysees), to the woful disappointment of its
enthusiastic inventor, who, however, consoles himself with the hope of
coming over to London for the purpose of testing his invention, as
soon as the return of fine weather shall render it prudent to make the
trial journey. In justice to M. Petin, we would observe, that the sole
point which he hopes to prove with this vessel is, _the possibility of
obtaining a fulcrum in the air_, justly considering that if the
question of _steering_ were affirmatively settled, the necessary
means, pecuniary and other, would soon be forthcoming to enable him to
improve upon, or to change the original construction, and to build the
mammoth vessels, containing closed apartments, warmed and fitted up
with every provision for comfort, in which he hopes to transport
several thousands of passengers at a time, and at a speed which it
al