The second finger (third digit) has the most literal meaning of all. Less commonly referred to as the long or tall finger, the digitus medius manus sits in the center of the hand, right between the digitus secondus manus and the ring finger. How the middle finger became an offensive gesture is another story altogether.
To see how the pump works, look at the drawing below. The pump consists of a small diameter pipe (called the piston) inserted into a larger diameter pipe (called the cylinder). The drawing shows the pump at two points during its operation. The top drawing shows air being drawn into the pipe by pulling out the piston. The bottom drawing shows air exiting the pipe when the piston is pushed back in. At the right end of the pipe is a commercially bought one-way valve.
A wedge is cut from a cylinder by slicing with a plane that intersects the base of the cylinder. The volume of a cylindrical wedge can be found by noting that the plane cutting the cylinder passes through the three points illustrated above (with), so the three-point form of the plane gives the equation. (1). wedge is cut from a cylinder by slicing with a plane that intersects the base of the cylinder. The volume of a cylindrical wedge can be found by noting that the plane cutting the cylinder passes through the three points illustrated above (with), so the three-point form of the plane gives the equation. (1).