The verge (or crown wheel) escapement is the earliest known type of mechanical escapement, the mechanism in a mechanical clock that controls its rate by allowing the gear train to advance at regular intervals or 'ticks'.he verge (or crown wheel) escapement is the earliest known type of mechanical escapement, the mechanism in a mechanical clock that controls its rate by allowing the gear train to advance at regular intervals or 'ticks'.
You need the foci for some construction methods. Just draw radii of length a from the ends of the minor axis. Given the foci, however, you can't uniquely determine the axes. You need additional information such as the length of one axis.
A tangent is a line that just touches a curve at one point, without cutting across it. Here is a tangent to an ellipse: Here is a cool thing: the tangent line has equal angles with the two lines going to each focus! Try bringing the two focus points together (so the ellipse is a circle) ... what do you notice? Section of a Cone. You can also get an ellipse when you slice through a cone (but not too steep a slice, or you get a parabola or hyperbola). In fact the ellipse is a conic section (a section of a cone) with an eccentricity between 0 and 1. Equation By placing an ellipse on an x-y graph (with its major axis on the x-axis and minor axis on the y-axis), the equation of the curve is: