He turned, and was off up the stairs, propelling his bewildered wife before him.
The oblique line referred to as running diagonally across the wing virtually divides the wing into an active and a passive part, the former elevating and propelling, the latter sustaining.
A, Large aeroplane; b, Small aeroplane; c, Propelling screws.
When the wind acts on the surface of the sea it drives before it the particles of the surface layer of water, and, as these cannot be parted from those immediately beneath, the internal friction of the fluid causes the propelling impulse to act through a considerable depth, and if the wind continued long enough it would ultimately set the whole mass of the ocean in motion 'right down to the bottom.
Of the energy exerted by the powder in exploding will be employed in propelling the ball, and ih in producing the recoil of the gun, provided the gun up to the instant of the balls quitting the muzzle meets with no resistance to its recoil except the friction of the ball.