In this instance a very slight movement at the root of the pinion, or that end of the lever directed towards the body, 1 is followed by an immense sweep of the extremity of the wing, where its elevating and propelling power is greatest - this arrangement ensuring that the large quantity of air necessary for support and propulsion shall be compressed under the most favourable conditions.
He took out patents for lamps to burn oil of tar, for the propulsion of ships at sea, for facilitating excavation, mining and sinking, for rotary steam-engines and for other purposes; and so early as 1843 he was an advocate of the employment of steam and the screw propeller in warships.
That the posterior margin of the wing yields to a slight extent during both the down and up strokes will readily be admitted, alike because of the very delicate and highly elastic properties of the posterior margins of the wing, and because of the comparatively great force employed in its propulsion; but that it does not yield to the extent stated by Marey is a matter of absolute certainty.
Human feet provide poor propulsion, so fins help move the body through the water; this is a big help when a diver is carrying equipment that creates drag.
Prior to the 19th century, wind energy was primarily used for the purposes of boat propulsion, grinding grains to make bread and other food items, and to pump water for irrigation and consumption.